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Merge branch 'linus' into irq/genirq

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Ingo Molnar
2009-01-16 17:46:22 +01:00
parent efdc64f0c7 7cb36b6ccd
commit 5a2dd72abd
8824 changed files with 1017204 additions and 239449 deletions
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1
.mailmap
View File

@ -32,6 +32,7 @@ Christoph Hellwig <hch@lst.de>
Corey Minyard <minyard@acm.org>
David Brownell <david-b@pacbell.net>
David Woodhouse <dwmw2@shinybook.infradead.org>
Dmitry Eremin-Solenikov <dbaryshkov@gmail.com>
Domen Puncer <domen@coderock.org>
Douglas Gilbert <dougg@torque.net>
Ed L. Cashin <ecashin@coraid.com>

38
CREDITS
View File

@ -369,10 +369,10 @@ P: 1024/8462A731 4C 55 86 34 44 59 A7 99 2B 97 88 4A 88 9A 0D 97
D: sun4 port, Sparc hacker
N: Hugh Blemings
E: hugh@misc.nu
W: http://misc.nu/hugh/
D: Author and maintainer of the Keyspan USB to Serial drivers
S: Po Box 234
E: hugh@blemings.org
W: http://blemings.org/hugh
D: Original author of the Keyspan USB to serial drivers, random PowerPC hacker
S: PO Box 234
S: Belconnen ACT 2616
S: Australia
@ -464,6 +464,11 @@ S: 1200 Goldenrod Dr.
S: Nampa, Idaho 83686
S: USA
N: Dirk J. Brandewie
E: dirk.j.brandewie@intel.com
E: linux-wimax@intel.com
D: Intel Wireless WiMAX Connection 2400 SDIO driver
N: Derrick J. Brashear
E: shadow@dementia.org
W: http://www.dementia.org/~shadow
@ -1681,7 +1686,7 @@ E: ajoshi@shell.unixbox.com
D: fbdev hacking
N: Jesper Juhl
E: jesper.juhl@gmail.com
E: jj@chaosbits.net
D: Various fixes, cleanups and minor features all over the tree.
D: Wrote initial version of the hdaps driver (since passed on to others).
S: Lemnosvej 1, 3.tv
@ -2119,6 +2124,11 @@ N: H.J. Lu
E: hjl@gnu.ai.mit.edu
D: GCC + libraries hacker
N: Yanir Lubetkin
E: yanirx.lubatkin@intel.com
E: linux-wimax@intel.com
D: Intel Wireless WiMAX Connection 2400 driver
N: Michal Ludvig
E: michal@logix.cz
E: michal.ludvig@asterisk.co.nz
@ -2693,6 +2703,13 @@ S: RR #5, 497 Pole Line Road
S: Thunder Bay, Ontario
S: CANADA P7C 5M9
N: Inaky Perez-Gonzalez
E: inaky.perez-gonzalez@intel.com
E: linux-wimax@intel.com
E: inakypg@yahoo.com
D: WiMAX stack
D: Intel Wireless WiMAX Connection 2400 driver
N: Yuri Per
E: yuri@pts.mipt.ru
D: Some smbfs fixes
@ -3769,14 +3786,11 @@ S: The Netherlands
N: David Woodhouse
E: dwmw2@infradead.org
D: ARCnet stuff, Applicom board driver, SO_BINDTODEVICE,
D: some Alpha platform porting from 2.0, Memory Technology Devices,
D: Acquire watchdog timer, PC speaker driver maintenance,
D: JFFS2 file system, Memory Technology Device subsystem,
D: various other stuff that annoyed me by not working.
S: c/o Red Hat Engineering
S: Rustat House
S: 60 Clifton Road
S: Cambridge. CB1 7EG
S: c/o Intel Corporation
S: Pipers Way
S: Swindon. SN3 1RJ
S: England
N: Chris Wright

136
Documentation/ABI/testing/sysfs-class-regulator
View File

@ -3,8 +3,9 @@ Date: April 2008
KernelVersion: 2.6.26
Contact: Liam Girdwood <lrg@slimlogic.co.uk>
Description:
Each regulator directory will contain a field called
state. This holds the regulator output state.
Some regulator directories will contain a field called
state. This reports the regulator enable status, for
regulators which can report that value.
This will be one of the following strings:
@ -18,7 +19,8 @@ Description:
'disabled' means the regulator output is OFF and is not
supplying power to the system..
'unknown' means software cannot determine the state.
'unknown' means software cannot determine the state, or
the reported state is invalid.
NOTE: this field can be used in conjunction with microvolts
and microamps to determine regulator output levels.
@ -53,9 +55,10 @@ Date: April 2008
KernelVersion: 2.6.26
Contact: Liam Girdwood <lrg@slimlogic.co.uk>
Description:
Each regulator directory will contain a field called
Some regulator directories will contain a field called
microvolts. This holds the regulator output voltage setting
measured in microvolts (i.e. E-6 Volts).
measured in microvolts (i.e. E-6 Volts), for regulators
which can report that voltage.
NOTE: This value should not be used to determine the regulator
output voltage level as this value is the same regardless of
@ -67,9 +70,10 @@ Date: April 2008
KernelVersion: 2.6.26
Contact: Liam Girdwood <lrg@slimlogic.co.uk>
Description:
Each regulator directory will contain a field called
Some regulator directories will contain a field called
microamps. This holds the regulator output current limit
setting measured in microamps (i.e. E-6 Amps).
setting measured in microamps (i.e. E-6 Amps), for regulators
which can report that current.
NOTE: This value should not be used to determine the regulator
output current level as this value is the same regardless of
@ -81,8 +85,9 @@ Date: April 2008
KernelVersion: 2.6.26
Contact: Liam Girdwood <lrg@slimlogic.co.uk>
Description:
Each regulator directory will contain a field called
opmode. This holds the regulator operating mode setting.
Some regulator directories will contain a field called
opmode. This holds the current regulator operating mode,
for regulators which can report it.
The opmode value can be one of the following strings:
@ -92,7 +97,7 @@ Description:
'standby'
'unknown'
The modes are described in include/linux/regulator/regulator.h
The modes are described in include/linux/regulator/consumer.h
NOTE: This value should not be used to determine the regulator
output operating mode as this value is the same regardless of
@ -104,9 +109,10 @@ Date: April 2008
KernelVersion: 2.6.26
Contact: Liam Girdwood <lrg@slimlogic.co.uk>
Description:
Each regulator directory will contain a field called
Some regulator directories will contain a field called
min_microvolts. This holds the minimum safe working regulator
output voltage setting for this domain measured in microvolts.
output voltage setting for this domain measured in microvolts,
for regulators which support voltage constraints.
NOTE: this will return the string 'constraint not defined' if
the power domain has no min microvolts constraint defined by
@ -118,9 +124,10 @@ Date: April 2008
KernelVersion: 2.6.26
Contact: Liam Girdwood <lrg@slimlogic.co.uk>
Description:
Each regulator directory will contain a field called
Some regulator directories will contain a field called
max_microvolts. This holds the maximum safe working regulator
output voltage setting for this domain measured in microvolts.
output voltage setting for this domain measured in microvolts,
for regulators which support voltage constraints.
NOTE: this will return the string 'constraint not defined' if
the power domain has no max microvolts constraint defined by
@ -132,10 +139,10 @@ Date: April 2008
KernelVersion: 2.6.26
Contact: Liam Girdwood <lrg@slimlogic.co.uk>
Description:
Each regulator directory will contain a field called
Some regulator directories will contain a field called
min_microamps. This holds the minimum safe working regulator
output current limit setting for this domain measured in
microamps.
microamps, for regulators which support current constraints.
NOTE: this will return the string 'constraint not defined' if
the power domain has no min microamps constraint defined by
@ -147,10 +154,10 @@ Date: April 2008
KernelVersion: 2.6.26
Contact: Liam Girdwood <lrg@slimlogic.co.uk>
Description:
Each regulator directory will contain a field called
Some regulator directories will contain a field called
max_microamps. This holds the maximum safe working regulator
output current limit setting for this domain measured in
microamps.
microamps, for regulators which support current constraints.
NOTE: this will return the string 'constraint not defined' if
the power domain has no max microamps constraint defined by
@ -185,7 +192,7 @@ Date: April 2008
KernelVersion: 2.6.26
Contact: Liam Girdwood <lrg@slimlogic.co.uk>
Description:
Each regulator directory will contain a field called
Some regulator directories will contain a field called
requested_microamps. This holds the total requested load
current in microamps for this regulator from all its consumer
devices.
@ -204,125 +211,102 @@ Date: May 2008
KernelVersion: 2.6.26
Contact: Liam Girdwood <lrg@slimlogic.co.uk>
Description:
Each regulator directory will contain a field called
Some regulator directories will contain a field called
suspend_mem_microvolts. This holds the regulator output
voltage setting for this domain measured in microvolts when
the system is suspended to memory.
NOTE: this will return the string 'not defined' if
the power domain has no suspend to memory voltage defined by
platform code.
the system is suspended to memory, for voltage regulators
implementing suspend voltage configuration constraints.
What: /sys/class/regulator/.../suspend_disk_microvolts
Date: May 2008
KernelVersion: 2.6.26
Contact: Liam Girdwood <lrg@slimlogic.co.uk>
Description:
Each regulator directory will contain a field called
Some regulator directories will contain a field called
suspend_disk_microvolts. This holds the regulator output
voltage setting for this domain measured in microvolts when
the system is suspended to disk.
NOTE: this will return the string 'not defined' if
the power domain has no suspend to disk voltage defined by
platform code.
the system is suspended to disk, for voltage regulators
implementing suspend voltage configuration constraints.
What: /sys/class/regulator/.../suspend_standby_microvolts
Date: May 2008
KernelVersion: 2.6.26
Contact: Liam Girdwood <lrg@slimlogic.co.uk>
Description:
Each regulator directory will contain a field called
Some regulator directories will contain a field called
suspend_standby_microvolts. This holds the regulator output
voltage setting for this domain measured in microvolts when
the system is suspended to standby.
NOTE: this will return the string 'not defined' if
the power domain has no suspend to standby voltage defined by
platform code.
the system is suspended to standby, for voltage regulators
implementing suspend voltage configuration constraints.
What: /sys/class/regulator/.../suspend_mem_mode
Date: May 2008
KernelVersion: 2.6.26
Contact: Liam Girdwood <lrg@slimlogic.co.uk>
Description:
Each regulator directory will contain a field called
Some regulator directories will contain a field called
suspend_mem_mode. This holds the regulator operating mode
setting for this domain when the system is suspended to
memory.
NOTE: this will return the string 'not defined' if
the power domain has no suspend to memory mode defined by
platform code.
memory, for regulators implementing suspend mode
configuration constraints.
What: /sys/class/regulator/.../suspend_disk_mode
Date: May 2008
KernelVersion: 2.6.26
Contact: Liam Girdwood <lrg@slimlogic.co.uk>
Description:
Each regulator directory will contain a field called
Some regulator directories will contain a field called
suspend_disk_mode. This holds the regulator operating mode
setting for this domain when the system is suspended to disk.
NOTE: this will return the string 'not defined' if
the power domain has no suspend to disk mode defined by
platform code.
setting for this domain when the system is suspended to disk,
for regulators implementing suspend mode configuration
constraints.
What: /sys/class/regulator/.../suspend_standby_mode
Date: May 2008
KernelVersion: 2.6.26
Contact: Liam Girdwood <lrg@slimlogic.co.uk>
Description:
Each regulator directory will contain a field called
Some regulator directories will contain a field called
suspend_standby_mode. This holds the regulator operating mode
setting for this domain when the system is suspended to
standby.
NOTE: this will return the string 'not defined' if
the power domain has no suspend to standby mode defined by
platform code.
standby, for regulators implementing suspend mode
configuration constraints.
What: /sys/class/regulator/.../suspend_mem_state
Date: May 2008
KernelVersion: 2.6.26
Contact: Liam Girdwood <lrg@slimlogic.co.uk>
Description:
Each regulator directory will contain a field called
Some regulator directories will contain a field called
suspend_mem_state. This holds the regulator operating state
when suspended to memory.
when suspended to memory, for regulators implementing suspend
configuration constraints.
This will be one of the following strings:
'enabled'
'disabled'
'not defined'
This will be one of the same strings reported by
the "state" attribute.
What: /sys/class/regulator/.../suspend_disk_state
Date: May 2008
KernelVersion: 2.6.26
Contact: Liam Girdwood <lrg@slimlogic.co.uk>
Description:
Each regulator directory will contain a field called
Some regulator directories will contain a field called
suspend_disk_state. This holds the regulator operating state
when suspended to disk.
when suspended to disk, for regulators implementing
suspend configuration constraints.
This will be one of the following strings:
'enabled'
'disabled'
'not defined'
This will be one of the same strings reported by
the "state" attribute.
What: /sys/class/regulator/.../suspend_standby_state
Date: May 2008
KernelVersion: 2.6.26
Contact: Liam Girdwood <lrg@slimlogic.co.uk>
Description:
Each regulator directory will contain a field called
Some regulator directories will contain a field called
suspend_standby_state. This holds the regulator operating
state when suspended to standby.
state when suspended to standby, for regulators implementing
suspend configuration constraints.
This will be one of the following strings:
'enabled'
'disabled'
'not defined'
This will be one of the same strings reported by
the "state" attribute.

14
Documentation/ABI/testing/sysfs-class-uwb_rc
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@ -32,14 +32,16 @@ Contact: linux-usb@vger.kernel.org
Description:
Write:
<channel> [<bpst offset>]
<channel>
to start beaconing on a specific channel, or stop
beaconing if <channel> is -1. Valid channels depends
on the radio controller's supported band groups.
to force a specific channel to be used when beaconing,
or, if <channel> is -1, to prohibit beaconing. If
<channel> is 0, then the default channel selection
algorithm will be used. Valid channels depends on the
radio controller's supported band groups.
<bpst offset> may be used to try and join a specific
beacon group if more than one was found during a scan.
Reading returns the currently active channel, or -1 if
the radio controller is not beaconing.
What: /sys/class/uwb_rc/uwbN/scan
Date: July 2008

53
Documentation/ABI/testing/sysfs-devices-memory
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@ -6,7 +6,6 @@ Description:
internal state of the kernel memory blocks. Files could be
added or removed dynamically to represent hot-add/remove
operations.
Users: hotplug memory add/remove tools
https://w3.opensource.ibm.com/projects/powerpc-utils/
@ -19,6 +18,56 @@ Description:
This is useful for a user-level agent to determine
identify removable sections of the memory before attempting
potentially expensive hot-remove memory operation
Users: hotplug memory remove tools
https://w3.opensource.ibm.com/projects/powerpc-utils/
What: /sys/devices/system/memory/memoryX/phys_device
Date: September 2008
Contact: Badari Pulavarty <pbadari@us.ibm.com>
Description:
The file /sys/devices/system/memory/memoryX/phys_device
is read-only and is designed to show the name of physical
memory device. Implementation is currently incomplete.
What: /sys/devices/system/memory/memoryX/phys_index
Date: September 2008
Contact: Badari Pulavarty <pbadari@us.ibm.com>
Description:
The file /sys/devices/system/memory/memoryX/phys_index
is read-only and contains the section ID in hexadecimal
which is equivalent to decimal X contained in the
memory section directory name.
What: /sys/devices/system/memory/memoryX/state
Date: September 2008
Contact: Badari Pulavarty <pbadari@us.ibm.com>
Description:
The file /sys/devices/system/memory/memoryX/state
is read-write. When read, it's contents show the
online/offline state of the memory section. When written,
root can toggle the the online/offline state of a removable
memory section (see removable file description above)
using the following commands.
# echo online > /sys/devices/system/memory/memoryX/state
# echo offline > /sys/devices/system/memory/memoryX/state
For example, if /sys/devices/system/memory/memory22/removable
contains a value of 1 and
/sys/devices/system/memory/memory22/state contains the
string "online" the following command can be executed by
by root to offline that section.
# echo offline > /sys/devices/system/memory/memory22/state
Users: hotplug memory remove tools
https://w3.opensource.ibm.com/projects/powerpc-utils/
What: /sys/devices/system/node/nodeX/memoryY
Date: September 2008
Contact: Gary Hade <garyhade@us.ibm.com>
Description:
When CONFIG_NUMA is enabled
/sys/devices/system/node/nodeX/memoryY is a symbolic link that
points to the corresponding /sys/devices/system/memory/memoryY
memory section directory. For example, the following symbolic
link is created for memory section 9 on node0.
/sys/devices/system/node/node0/memory9 -> ../../memory/memory9

9
Documentation/DMA-API.txt
View File

@ -170,16 +170,15 @@ Returns: 0 if successful and a negative error if not.
u64
dma_get_required_mask(struct device *dev)
After setting the mask with dma_set_mask(), this API returns the
actual mask (within that already set) that the platform actually
requires to operate efficiently. Usually this means the returned mask
This API returns the mask that the platform requires to
operate efficiently. Usually this means the returned mask
is the minimum required to cover all of memory. Examining the
required mask gives drivers with variable descriptor sizes the
opportunity to use smaller descriptors as necessary.
Requesting the required mask does not alter the current mask. If you
wish to take advantage of it, you should issue another dma_set_mask()
call to lower the mask again.
wish to take advantage of it, you should issue a dma_set_mask()
call to set the mask to the value returned.
Part Id - Streaming DMA mappings

2
Documentation/DMA-mapping.txt
View File

@ -26,7 +26,7 @@ mapped only for the time they are actually used and unmapped after the DMA
transfer.
The following API will work of course even on platforms where no such
hardware exists, see e.g. include/asm-i386/pci.h for how it is implemented on
hardware exists, see e.g. arch/x86/include/asm/pci.h for how it is implemented on
top of the virt_to_bus interface.
First of all, you should make sure

4
Documentation/DocBook/Makefile
View File

@ -6,13 +6,13 @@
# To add a new book the only step required is to add the book to the
# list of DOCBOOKS.
DOCBOOKS := wanbook.xml z8530book.xml mcabook.xml \
DOCBOOKS := z8530book.xml mcabook.xml \
kernel-hacking.xml kernel-locking.xml deviceiobook.xml \
procfs-guide.xml writing_usb_driver.xml networking.xml \
kernel-api.xml filesystems.xml lsm.xml usb.xml kgdb.xml \
gadget.xml libata.xml mtdnand.xml librs.xml rapidio.xml \
genericirq.xml s390-drivers.xml uio-howto.xml scsi.xml \
mac80211.xml debugobjects.xml sh.xml
mac80211.xml debugobjects.xml sh.xml regulator.xml
###
# The build process is as follows (targets):

11
Documentation/DocBook/networking.tmpl
View File

@ -74,6 +74,14 @@
!Enet/sunrpc/rpcb_clnt.c
!Enet/sunrpc/clnt.c
</sect1>
<sect1><title>WiMAX</title>
!Enet/wimax/op-msg.c
!Enet/wimax/op-reset.c
!Enet/wimax/op-rfkill.c
!Enet/wimax/stack.c
!Iinclude/net/wimax.h
!Iinclude/linux/wimax.h
</sect1>
</chapter>
<chapter id="netdev">
@ -98,9 +106,6 @@
X!Enet/core/wireless.c
</sect1>
-->
<sect1><title>Synchronous PPP</title>
!Edrivers/net/wan/syncppp.c
</sect1>
</chapter>
</book>

304
Documentation/DocBook/regulator.tmpl Normal file
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@ -0,0 +1,304 @@
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.1.2//EN"
"http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd" []>
<book id="regulator-api">
<bookinfo>
<title>Voltage and current regulator API</title>
<authorgroup>
<author>
<firstname>Liam</firstname>
<surname>Girdwood</surname>
<affiliation>
<address>
<email>lrg@slimlogic.co.uk</email>
</address>
</affiliation>
</author>
<author>
<firstname>Mark</firstname>
<surname>Brown</surname>
<affiliation>
<orgname>Wolfson Microelectronics</orgname>
<address>
<email>broonie@opensource.wolfsonmicro.com</email>
</address>
</affiliation>
</author>
</authorgroup>
<copyright>
<year>2007-2008</year>
<holder>Wolfson Microelectronics</holder>
</copyright>
<copyright>
<year>2008</year>
<holder>Liam Girdwood</holder>
</copyright>
<legalnotice>
<para>
This documentation is free software; you can redistribute
it and/or modify it under the terms of the GNU General Public
License version 2 as published by the Free Software Foundation.
</para>
<para>
This program is distributed in the hope that it will be
useful, but WITHOUT ANY WARRANTY; without even the implied
warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
See the GNU General Public License for more details.
</para>
<para>
You should have received a copy of the GNU General Public
License along with this program; if not, write to the Free
Software Foundation, Inc., 59 Temple Place, Suite 330, Boston,
MA 02111-1307 USA
</para>
<para>
For more details see the file COPYING in the source
distribution of Linux.
</para>
</legalnotice>
</bookinfo>
<toc></toc>
<chapter id="intro">
<title>Introduction</title>
<para>
This framework is designed to provide a standard kernel
interface to control voltage and current regulators.
</para>
<para>
The intention is to allow systems to dynamically control
regulator power output in order to save power and prolong
battery life. This applies to both voltage regulators (where
voltage output is controllable) and current sinks (where current
limit is controllable).
</para>
<para>
Note that additional (and currently more complete) documentation
is available in the Linux kernel source under
<filename>Documentation/power/regulator</filename>.
</para>
<sect1 id="glossary">
<title>Glossary</title>
<para>
The regulator API uses a number of terms which may not be
familiar:
</para>
<glossary>
<glossentry>
<glossterm>Regulator</glossterm>
<glossdef>
<para>
Electronic device that supplies power to other devices. Most
regulators can enable and disable their output and some can also
control their output voltage or current.
</para>
</glossdef>
</glossentry>
<glossentry>
<glossterm>Consumer</glossterm>
<glossdef>
<para>
Electronic device which consumes power provided by a regulator.
These may either be static, requiring only a fixed supply, or
dynamic, requiring active management of the regulator at
runtime.
</para>
</glossdef>
</glossentry>
<glossentry>
<glossterm>Power Domain</glossterm>
<glossdef>
<para>
The electronic circuit supplied by a given regulator, including
the regulator and all consumer devices. The configuration of
the regulator is shared between all the components in the
circuit.
</para>
</glossdef>
</glossentry>
<glossentry>
<glossterm>Power Management Integrated Circuit</glossterm>
<acronym>PMIC</acronym>
<glossdef>
<para>
An IC which contains numerous regulators and often also other
subsystems. In an embedded system the primary PMIC is often
equivalent to a combination of the PSU and southbridge in a
desktop system.
</para>
</glossdef>
</glossentry>
</glossary>
</sect1>
</chapter>
<chapter id="consumer">
<title>Consumer driver interface</title>
<para>
This offers a similar API to the kernel clock framework.
Consumer drivers use <link
linkend='API-regulator-get'>get</link> and <link
linkend='API-regulator-put'>put</link> operations to acquire and
release regulators. Functions are
provided to <link linkend='API-regulator-enable'>enable</link>
and <link linkend='API-regulator-disable'>disable</link> the
reguator and to get and set the runtime parameters of the
regulator.
</para>
<para>
When requesting regulators consumers use symbolic names for their
supplies, such as "Vcc", which are mapped into actual regulator
devices by the machine interface.
</para>
<para>
A stub version of this API is provided when the regulator
framework is not in use in order to minimise the need to use
ifdefs.
</para>
<sect1 id="consumer-enable">
<title>Enabling and disabling</title>
<para>
The regulator API provides reference counted enabling and
disabling of regulators. Consumer devices use the <function><link
linkend='API-regulator-enable'>regulator_enable</link></function>
and <function><link
linkend='API-regulator-disable'>regulator_disable</link>
</function> functions to enable and disable regulators. Calls
to the two functions must be balanced.
</para>
<para>
Note that since multiple consumers may be using a regulator and
machine constraints may not allow the regulator to be disabled
there is no guarantee that calling
<function>regulator_disable</function> will actually cause the
supply provided by the regulator to be disabled. Consumer
drivers should assume that the regulator may be enabled at all
times.
</para>
</sect1>
<sect1 id="consumer-config">
<title>Configuration</title>
<para>
Some consumer devices may need to be able to dynamically
configure their supplies. For example, MMC drivers may need to
select the correct operating voltage for their cards. This may
be done while the regulator is enabled or disabled.
</para>
<para>
The <function><link
linkend='API-regulator-set-voltage'>regulator_set_voltage</link>
</function> and <function><link
linkend='API-regulator-set-current-limit'
>regulator_set_current_limit</link>
</function> functions provide the primary interface for this.
Both take ranges of voltages and currents, supporting drivers
that do not require a specific value (eg, CPU frequency scaling
normally permits the CPU to use a wider range of supply
voltages at lower frequencies but does not require that the
supply voltage be lowered). Where an exact value is required
both minimum and maximum values should be identical.
</para>
</sect1>
<sect1 id="consumer-callback">
<title>Callbacks</title>
<para>
Callbacks may also be <link
linkend='API-regulator-register-notifier'>registered</link>
for events such as regulation failures.
</para>
</sect1>
</chapter>
<chapter id="driver">
<title>Regulator driver interface</title>
<para>
Drivers for regulator chips <link
linkend='API-regulator-register'>register</link> the regulators
with the regulator core, providing operations structures to the
core. A <link
linkend='API-regulator-notifier-call-chain'>notifier</link> interface
allows error conditions to be reported to the core.
</para>
<para>
Registration should be triggered by explicit setup done by the
platform, supplying a <link
linkend='API-struct-regulator-init-data'>struct
regulator_init_data</link> for the regulator containing
<link linkend='machine-constraint'>constraint</link> and
<link linkend='machine-supply'>supply</link> information.
</para>
</chapter>
<chapter id="machine">
<title>Machine interface</title>
<para>
This interface provides a way to define how regulators are
connected to consumers on a given system and what the valid
operating parameters are for the system.
</para>
<sect1 id="machine-supply">
<title>Supplies</title>
<para>
Regulator supplies are specified using <link
linkend='API-struct-regulator-consumer-supply'>struct
regulator_consumer_supply</link>. This is done at
<link linkend='driver'>driver registration
time</link> as part of the machine constraints.
</para>
</sect1>
<sect1 id="machine-constraint">
<title>Constraints</title>
<para>
As well as definining the connections the machine interface
also provides constraints definining the operations that
clients are allowed to perform and the parameters that may be
set. This is required since generally regulator devices will
offer more flexibility than it is safe to use on a given
system, for example supporting higher supply voltages than the
consumers are rated for.
</para>
<para>
This is done at <link linkend='driver'>driver
registration time</link> by providing a <link
linkend='API-struct-regulation-constraints'>struct
regulation_constraints</link>.
</para>
<para>
The constraints may also specify an initial configuration for the
regulator in the constraints, which is particularly useful for
use with static consumers.
</para>
</sect1>
</chapter>
<chapter id="api">
<title>API reference</title>
<para>
Due to limitations of the kernel documentation framework and the
existing layout of the source code the entire regulator API is
documented here.
</para>
!Iinclude/linux/regulator/consumer.h
!Iinclude/linux/regulator/machine.h
!Iinclude/linux/regulator/driver.h
!Edrivers/regulator/core.c
</chapter>
</book>

101
Documentation/DocBook/uio-howto.tmpl
View File

@ -41,6 +41,12 @@ GPL version 2.
</abstract>
<revhistory>
<revision>
<revnumber>0.6</revnumber>
<date>2008-12-05</date>
<authorinitials>hjk</authorinitials>
<revremark>Added description of portio sysfs attributes.</revremark>
</revision>
<revision>
<revnumber>0.5</revnumber>
<date>2008-05-22</date>
@ -318,6 +324,54 @@ interested in translating it, please email me
offset = N * getpagesize();
</programlisting>
<para>
Sometimes there is hardware with memory-like regions that can not be
mapped with the technique described here, but there are still ways to
access them from userspace. The most common example are x86 ioports.
On x86 systems, userspace can access these ioports using
<function>ioperm()</function>, <function>iopl()</function>,
<function>inb()</function>, <function>outb()</function>, and similar
functions.
</para>
<para>
Since these ioport regions can not be mapped, they will not appear under
<filename>/sys/class/uio/uioX/maps/</filename> like the normal memory
described above. Without information about the port regions a hardware
has to offer, it becomes difficult for the userspace part of the
driver to find out which ports belong to which UIO device.
</para>
<para>
To address this situation, the new directory
<filename>/sys/class/uio/uioX/portio/</filename> was added. It only
exists if the driver wants to pass information about one or more port
regions to userspace. If that is the case, subdirectories named
<filename>port0</filename>, <filename>port1</filename>, and so on,
will appear underneath
<filename>/sys/class/uio/uioX/portio/</filename>.
</para>
<para>
Each <filename>portX/</filename> directory contains three read-only
files that show start, size, and type of the port region:
</para>
<itemizedlist>
<listitem>
<para>
<filename>start</filename>: The first port of this region.
</para>
</listitem>
<listitem>
<para>
<filename>size</filename>: The number of ports in this region.
</para>
</listitem>
<listitem>
<para>
<filename>porttype</filename>: A string describing the type of port.
</para>
</listitem>
</itemizedlist>
</sect1>
</chapter>
@ -339,12 +393,12 @@ offset = N * getpagesize();
<itemizedlist>
<listitem><para>
<varname>char *name</varname>: Required. The name of your driver as
<varname>const char *name</varname>: Required. The name of your driver as
it will appear in sysfs. I recommend using the name of your module for this.
</para></listitem>
<listitem><para>
<varname>char *version</varname>: Required. This string appears in
<varname>const char *version</varname>: Required. This string appears in
<filename>/sys/class/uio/uioX/version</filename>.
</para></listitem>
@ -355,6 +409,13 @@ mapping you need to fill one of the <varname>uio_mem</varname> structures.
See the description below for details.
</para></listitem>
<listitem><para>
<varname>struct uio_port port[ MAX_UIO_PORTS_REGIONS ]</varname>: Required
if you want to pass information about ioports to userspace. For each port
region you need to fill one of the <varname>uio_port</varname> structures.
See the description below for details.
</para></listitem>
<listitem><para>
<varname>long irq</varname>: Required. If your hardware generates an
interrupt, it's your modules task to determine the irq number during
@ -448,6 +509,42 @@ Please do not touch the <varname>kobj</varname> element of
<varname>struct uio_mem</varname>! It is used by the UIO framework
to set up sysfs files for this mapping. Simply leave it alone.
</para>
<para>
Sometimes, your device can have one or more port regions which can not be
mapped to userspace. But if there are other possibilities for userspace to
access these ports, it makes sense to make information about the ports
available in sysfs. For each region, you have to set up a
<varname>struct uio_port</varname> in the <varname>port[]</varname> array.
Here's a description of the fields of <varname>struct uio_port</varname>:
</para>
<itemizedlist>
<listitem><para>
<varname>char *porttype</varname>: Required. Set this to one of the predefined
constants. Use <varname>UIO_PORT_X86</varname> for the ioports found in x86
architectures.
</para></listitem>
<listitem><para>
<varname>unsigned long start</varname>: Required if the port region is used.
Fill in the number of the first port of this region.
</para></listitem>
<listitem><para>
<varname>unsigned long size</varname>: Fill in the number of ports in this
region. If <varname>size</varname> is zero, the region is considered unused.
Note that you <emphasis>must</emphasis> initialize <varname>size</varname>
with zero for all unused regions.
</para></listitem>
</itemizedlist>
<para>
Please do not touch the <varname>portio</varname> element of
<varname>struct uio_port</varname>! It is used internally by the UIO
framework to set up sysfs files for this region. Simply leave it alone.
</para>
</sect1>
<sect1 id="adding_irq_handler">

99
Documentation/DocBook/wanbook.tmpl
View File

@ -1,99 +0,0 @@
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.1.2//EN"
"http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd" []>
<book id="WANGuide">
<bookinfo>
<title>Synchronous PPP and Cisco HDLC Programming Guide</title>
<authorgroup>
<author>
<firstname>Alan</firstname>
<surname>Cox</surname>
<affiliation>
<address>
<email>alan@lxorguk.ukuu.org.uk</email>
</address>
</affiliation>
</author>
</authorgroup>
<copyright>
<year>2000</year>
<holder>Alan Cox</holder>
</copyright>
<legalnotice>
<para>
This documentation is free software; you can redistribute
it and/or modify it under the terms of the GNU General Public
License as published by the Free Software Foundation; either
version 2 of the License, or (at your option) any later
version.
</para>
<para>
This program is distributed in the hope that it will be
useful, but WITHOUT ANY WARRANTY; without even the implied
warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
See the GNU General Public License for more details.
</para>
<para>
You should have received a copy of the GNU General Public
License along with this program; if not, write to the Free
Software Foundation, Inc., 59 Temple Place, Suite 330, Boston,
MA 02111-1307 USA
</para>
<para>
For more details see the file COPYING in the source
distribution of Linux.
</para>
</legalnotice>
</bookinfo>
<toc></toc>
<chapter id="intro">
<title>Introduction</title>
<para>
The syncppp drivers in Linux provide a fairly complete
implementation of Cisco HDLC and a minimal implementation of
PPP. The longer term goal is to switch the PPP layer to the
generic PPP interface that is new in Linux 2.3.x. The API should
remain unchanged when this is done, but support will then be
available for IPX, compression and other PPP features
</para>
</chapter>
<chapter id="bugs">
<title>Known Bugs And Assumptions</title>
<para>
<variablelist>
<varlistentry><term>PPP is minimal</term>
<listitem>
<para>
The current PPP implementation is very basic, although sufficient
for most wan usages.
</para>
</listitem></varlistentry>
<varlistentry><term>Cisco HDLC Quirks</term>
<listitem>
<para>
Currently we do not end all packets with the correct Cisco multicast
or unicast flags. Nothing appears to mind too much but this should
be corrected.
</para>
</listitem></varlistentry>
</variablelist>
</para>
</chapter>
<chapter id="pubfunctions">
<title>Public Functions Provided</title>
!Edrivers/net/wan/syncppp.c
</chapter>
</book>

3
Documentation/PCI/pci.txt
View File

@ -294,7 +294,8 @@ NOTE: pci_enable_device() can fail! Check the return value.
pci_set_master() will enable DMA by setting the bus master bit
in the PCI_COMMAND register. It also fixes the latency timer value if
it's set to something bogus by the BIOS.
it's set to something bogus by the BIOS. pci_clear_master() will
disable DMA by clearing the bus master bit.
If the PCI device can use the PCI Memory-Write-Invalidate transaction,
call pci_set_mwi(). This enables the PCI_COMMAND bit for Mem-Wr-Inval

4
Documentation/RCU/00-INDEX
View File

@ -12,10 +12,14 @@ rcuref.txt
- Reference-count design for elements of lists/arrays protected by RCU
rcu.txt
- RCU Concepts
rcubarrier.txt
- Unloading modules that use RCU callbacks
RTFP.txt
- List of RCU papers (bibliography) going back to 1980.
torture.txt
- RCU Torture Test Operation (CONFIG_RCU_TORTURE_TEST)
trace.txt
- CONFIG_RCU_TRACE debugfs files and formats
UP.txt
- RCU on Uniprocessor Systems
whatisRCU.txt

304
Documentation/RCU/rcubarrier.txt Normal file
View File

@ -0,0 +1,304 @@
RCU and Unloadable Modules
[Originally published in LWN Jan. 14, 2007: http://lwn.net/Articles/217484/]
RCU (read-copy update) is a synchronization mechanism that can be thought
of as a replacement for read-writer locking (among other things), but with
very low-overhead readers that are immune to deadlock, priority inversion,
and unbounded latency. RCU read-side critical sections are delimited
by rcu_read_lock() and rcu_read_unlock(), which, in non-CONFIG_PREEMPT
kernels, generate no code whatsoever.
This means that RCU writers are unaware of the presence of concurrent
readers, so that RCU updates to shared data must be undertaken quite
carefully, leaving an old version of the data structure in place until all
pre-existing readers have finished. These old versions are needed because
such readers might hold a reference to them. RCU updates can therefore be
rather expensive, and RCU is thus best suited for read-mostly situations.
How can an RCU writer possibly determine when all readers are finished,
given that readers might well leave absolutely no trace of their
presence? There is a synchronize_rcu() primitive that blocks until all
pre-existing readers have completed. An updater wishing to delete an
element p from a linked list might do the following, while holding an
appropriate lock, of course:
list_del_rcu(p);
synchronize_rcu();
kfree(p);
But the above code cannot be used in IRQ context -- the call_rcu()
primitive must be used instead. This primitive takes a pointer to an
rcu_head struct placed within the RCU-protected data structure and
another pointer to a function that may be invoked later to free that
structure. Code to delete an element p from the linked list from IRQ
context might then be as follows:
list_del_rcu(p);
call_rcu(&p->rcu, p_callback);
Since call_rcu() never blocks, this code can safely be used from within
IRQ context. The function p_callback() might be defined as follows:
static void p_callback(struct rcu_head *rp)
{
struct pstruct *p = container_of(rp, struct pstruct, rcu);
kfree(p);
}
Unloading Modules That Use call_rcu()
But what if p_callback is defined in an unloadable module?
If we unload the module while some RCU callbacks are pending,
the CPUs executing these callbacks are going to be severely
disappointed when they are later invoked, as fancifully depicted at
http://lwn.net/images/ns/kernel/rcu-drop.jpg.
We could try placing a synchronize_rcu() in the module-exit code path,
but this is not sufficient. Although synchronize_rcu() does wait for a
grace period to elapse, it does not wait for the callbacks to complete.
One might be tempted to try several back-to-back synchronize_rcu()
calls, but this is still not guaranteed to work. If there is a very
heavy RCU-callback load, then some of the callbacks might be deferred
in order to allow other processing to proceed. Such deferral is required
in realtime kernels in order to avoid excessive scheduling latencies.
rcu_barrier()
We instead need the rcu_barrier() primitive. This primitive is similar
to synchronize_rcu(), but instead of waiting solely for a grace
period to elapse, it also waits for all outstanding RCU callbacks to
complete. Pseudo-code using rcu_barrier() is as follows:
1. Prevent any new RCU callbacks from being posted.
2. Execute rcu_barrier().
3. Allow the module to be unloaded.
Quick Quiz #1: Why is there no srcu_barrier()?
The rcutorture module makes use of rcu_barrier in its exit function
as follows:
1 static void
2 rcu_torture_cleanup(void)
3 {
4 int i;
5
6 fullstop = 1;
7 if (shuffler_task != NULL) {
8 VERBOSE_PRINTK_STRING("Stopping rcu_torture_shuffle task");
9 kthread_stop(shuffler_task);
10 }
11 shuffler_task = NULL;
12
13 if (writer_task != NULL) {
14 VERBOSE_PRINTK_STRING("Stopping rcu_torture_writer task");
15 kthread_stop(writer_task);
16 }
17 writer_task = NULL;
18
19 if (reader_tasks != NULL) {
20 for (i = 0; i < nrealreaders; i++) {
21 if (reader_tasks[i] != NULL) {
22 VERBOSE_PRINTK_STRING(
23 "Stopping rcu_torture_reader task");
24 kthread_stop(reader_tasks[i]);
25 }
26 reader_tasks[i] = NULL;
27 }
28 kfree(reader_tasks);
29 reader_tasks = NULL;
30 }
31 rcu_torture_current = NULL;
32
33 if (fakewriter_tasks != NULL) {
34 for (i = 0; i < nfakewriters; i++) {
35 if (fakewriter_tasks[i] != NULL) {
36 VERBOSE_PRINTK_STRING(
37 "Stopping rcu_torture_fakewriter task");
38 kthread_stop(fakewriter_tasks[i]);
39 }
40 fakewriter_tasks[i] = NULL;
41 }
42 kfree(fakewriter_tasks);
43 fakewriter_tasks = NULL;
44 }
45
46 if (stats_task != NULL) {
47 VERBOSE_PRINTK_STRING("Stopping rcu_torture_stats task");
48 kthread_stop(stats_task);
49 }
50 stats_task = NULL;
51
52 /* Wait for all RCU callbacks to fire. */
53 rcu_barrier();
54
55 rcu_torture_stats_print(); /* -After- the stats thread is stopped! */
56
57 if (cur_ops->cleanup != NULL)
58 cur_ops->cleanup();
59 if (atomic_read(&n_rcu_torture_error))
60 rcu_torture_print_module_parms("End of test: FAILURE");
61 else
62 rcu_torture_print_module_parms("End of test: SUCCESS");
63 }
Line 6 sets a global variable that prevents any RCU callbacks from
re-posting themselves. This will not be necessary in most cases, since
RCU callbacks rarely include calls to call_rcu(). However, the rcutorture
module is an exception to this rule, and therefore needs to set this
global variable.
Lines 7-50 stop all the kernel tasks associated with the rcutorture
module. Therefore, once execution reaches line 53, no more rcutorture
RCU callbacks will be posted. The rcu_barrier() call on line 53 waits
for any pre-existing callbacks to complete.
Then lines 55-62 print status and do operation-specific cleanup, and
then return, permitting the module-unload operation to be completed.
Quick Quiz #2: Is there any other situation where rcu_barrier() might
be required?
Your module might have additional complications. For example, if your
module invokes call_rcu() from timers, you will need to first cancel all
the timers, and only then invoke rcu_barrier() to wait for any remaining
RCU callbacks to complete.
Implementing rcu_barrier()
Dipankar Sarma's implementation of rcu_barrier() makes use of the fact
that RCU callbacks are never reordered once queued on one of the per-CPU
queues. His implementation queues an RCU callback on each of the per-CPU
callback queues, and then waits until they have all started executing, at
which point, all earlier RCU callbacks are guaranteed to have completed.
The original code for rcu_barrier() was as follows:
1 void rcu_barrier(void)
2 {
3 BUG_ON(in_interrupt());
4 /* Take cpucontrol mutex to protect against CPU hotplug */
5 mutex_lock(&rcu_barrier_mutex);
6 init_completion(&rcu_barrier_completion);
7 atomic_set(&rcu_barrier_cpu_count, 0);
8 on_each_cpu(rcu_barrier_func, NULL, 0, 1);
9 wait_for_completion(&rcu_barrier_completion);
10 mutex_unlock(&rcu_barrier_mutex);
11 }
Line 3 verifies that the caller is in process context, and lines 5 and 10
use rcu_barrier_mutex to ensure that only one rcu_barrier() is using the
global completion and counters at a time, which are initialized on lines
6 and 7. Line 8 causes each CPU to invoke rcu_barrier_func(), which is
shown below. Note that the final "1" in on_each_cpu()'s argument list
ensures that all the calls to rcu_barrier_func() will have completed
before on_each_cpu() returns. Line 9 then waits for the completion.
This code was rewritten in 2008 to support rcu_barrier_bh() and
rcu_barrier_sched() in addition to the original rcu_barrier().
The rcu_barrier_func() runs on each CPU, where it invokes call_rcu()
to post an RCU callback, as follows:
1 static void rcu_barrier_func(void *notused)
2 {
3 int cpu = smp_processor_id();
4 struct rcu_data *rdp = &per_cpu(rcu_data, cpu);
5 struct rcu_head *head;
6
7 head = &rdp->barrier;
8 atomic_inc(&rcu_barrier_cpu_count);
9 call_rcu(head, rcu_barrier_callback);
10 }
Lines 3 and 4 locate RCU's internal per-CPU rcu_data structure,
which contains the struct rcu_head that needed for the later call to
call_rcu(). Line 7 picks up a pointer to this struct rcu_head, and line
8 increments a global counter. This counter will later be decremented
by the callback. Line 9 then registers the rcu_barrier_callback() on
the current CPU's queue.
The rcu_barrier_callback() function simply atomically decrements the
rcu_barrier_cpu_count variable and finalizes the completion when it
reaches zero, as follows:
1 static void rcu_barrier_callback(struct rcu_head *notused)
2 {
3 if (atomic_dec_and_test(&rcu_barrier_cpu_count))
4 complete(&rcu_barrier_completion);
5 }
Quick Quiz #3: What happens if CPU 0's rcu_barrier_func() executes
immediately (thus incrementing rcu_barrier_cpu_count to the
value one), but the other CPU's rcu_barrier_func() invocations
are delayed for a full grace period? Couldn't this result in
rcu_barrier() returning prematurely?
rcu_barrier() Summary
The rcu_barrier() primitive has seen relatively little use, since most
code using RCU is in the core kernel rather than in modules. However, if
you are using RCU from an unloadable module, you need to use rcu_barrier()
so that your module may be safely unloaded.
Answers to Quick Quizzes
Quick Quiz #1: Why is there no srcu_barrier()?
Answer: Since there is no call_srcu(), there can be no outstanding SRCU
callbacks. Therefore, there is no need to wait for them.
Quick Quiz #2: Is there any other situation where rcu_barrier() might
be required?
Answer: Interestingly enough, rcu_barrier() was not originally
implemented for module unloading. Nikita Danilov was using
RCU in a filesystem, which resulted in a similar situation at
filesystem-unmount time. Dipankar Sarma coded up rcu_barrier()
in response, so that Nikita could invoke it during the
filesystem-unmount process.
Much later, yours truly hit the RCU module-unload problem when
implementing rcutorture, and found that rcu_barrier() solves
this problem as well.
Quick Quiz #3: What happens if CPU 0's rcu_barrier_func() executes
immediately (thus incrementing rcu_barrier_cpu_count to the
value one), but the other CPU's rcu_barrier_func() invocations
are delayed for a full grace period? Couldn't this result in
rcu_barrier() returning prematurely?
Answer: This cannot happen. The reason is that on_each_cpu() has its last
argument, the wait flag, set to "1". This flag is passed through
to smp_call_function() and further to smp_call_function_on_cpu(),
causing this latter to spin until the cross-CPU invocation of
rcu_barrier_func() has completed. This by itself would prevent
a grace period from completing on non-CONFIG_PREEMPT kernels,
since each CPU must undergo a context switch (or other quiescent
state) before the grace period can complete. However, this is
of no use in CONFIG_PREEMPT kernels.
Therefore, on_each_cpu() disables preemption across its call
to smp_call_function() and also across the local call to
rcu_barrier_func(). This prevents the local CPU from context
switching, again preventing grace periods from completing. This
means that all CPUs have executed rcu_barrier_func() before
the first rcu_barrier_callback() can possibly execute, in turn
preventing rcu_barrier_cpu_count from prematurely reaching zero.
Currently, -rt implementations of RCU keep but a single global
queue for RCU callbacks, and thus do not suffer from this
problem. However, when the -rt RCU eventually does have per-CPU
callback queues, things will have to change. One simple change
is to add an rcu_read_lock() before line 8 of rcu_barrier()
and an rcu_read_unlock() after line 8 of this same function. If
you can think of a better change, please let me know!

167
Documentation/RCU/rculist_nulls.txt Normal file
View File

@ -0,0 +1,167 @@
Using hlist_nulls to protect read-mostly linked lists and
objects using SLAB_DESTROY_BY_RCU allocations.
Please read the basics in Documentation/RCU/listRCU.txt
Using special makers (called 'nulls') is a convenient way
to solve following problem :
A typical RCU linked list managing objects which are
allocated with SLAB_DESTROY_BY_RCU kmem_cache can
use following algos :
1) Lookup algo
--------------
rcu_read_lock()
begin:
obj = lockless_lookup(key);
if (obj) {
if (!try_get_ref(obj)) // might fail for free objects
goto begin;
/*
* Because a writer could delete object, and a writer could
* reuse these object before the RCU grace period, we
* must check key after geting the reference on object
*/
if (obj->key != key) { // not the object we expected
put_ref(obj);
goto begin;
}
}
rcu_read_unlock();
Beware that lockless_lookup(key) cannot use traditional hlist_for_each_entry_rcu()
but a version with an additional memory barrier (smp_rmb())
lockless_lookup(key)
{
struct hlist_node *node, *next;
for (pos = rcu_dereference((head)->first);
pos && ({ next = pos->next; smp_rmb(); prefetch(next); 1; }) &&
({ tpos = hlist_entry(pos, typeof(*tpos), member); 1; });
pos = rcu_dereference(next))
if (obj->key == key)
return obj;
return NULL;
And note the traditional hlist_for_each_entry_rcu() misses this smp_rmb() :
struct hlist_node *node;
for (pos = rcu_dereference((head)->first);
pos && ({ prefetch(pos->next); 1; }) &&
({ tpos = hlist_entry(pos, typeof(*tpos), member); 1; });
pos = rcu_dereference(pos->next))
if (obj->key == key)
return obj;
return NULL;
}
Quoting Corey Minyard :
"If the object is moved from one list to another list in-between the
time the hash is calculated and the next field is accessed, and the
object has moved to the end of a new list, the traversal will not
complete properly on the list it should have, since the object will
be on the end of the new list and there's not a way to tell it's on a
new list and restart the list traversal. I think that this can be
solved by pre-fetching the "next" field (with proper barriers) before
checking the key."
2) Insert algo :
----------------
We need to make sure a reader cannot read the new 'obj->obj_next' value
and previous value of 'obj->key'. Or else, an item could be deleted
from a chain, and inserted into another chain. If new chain was empty
before the move, 'next' pointer is NULL, and lockless reader can
not detect it missed following items in original chain.
/*
* Please note that new inserts are done at the head of list,
* not in the middle or end.
*/
obj = kmem_cache_alloc(...);
lock_chain(); // typically a spin_lock()
obj->key = key;
atomic_inc(&obj->refcnt);
/*
* we need to make sure obj->key is updated before obj->next
*/
smp_wmb();
hlist_add_head_rcu(&obj->obj_node, list);
unlock_chain(); // typically a spin_unlock()
3) Remove algo
--------------
Nothing special here, we can use a standard RCU hlist deletion.
But thanks to SLAB_DESTROY_BY_RCU, beware a deleted object can be reused
very very fast (before the end of RCU grace period)
if (put_last_reference_on(obj) {
lock_chain(); // typically a spin_lock()
hlist_del_init_rcu(&obj->obj_node);
unlock_chain(); // typically a spin_unlock()
kmem_cache_free(cachep, obj);
}
--------------------------------------------------------------------------
With hlist_nulls we can avoid extra smp_rmb() in lockless_lookup()
and extra smp_wmb() in insert function.
For example, if we choose to store the slot number as the 'nulls'
end-of-list marker for each slot of the hash table, we can detect
a race (some writer did a delete and/or a move of an object
to another chain) checking the final 'nulls' value if
the lookup met the end of chain. If final 'nulls' value
is not the slot number, then we must restart the lookup at
the begining. If the object was moved to same chain,
then the reader doesnt care : It might eventually
scan the list again without harm.
1) lookup algo
head = &table[slot];
rcu_read_lock();
begin:
hlist_nulls_for_each_entry_rcu(obj, node, head, member) {
if (obj->key == key) {
if (!try_get_ref(obj)) // might fail for free objects
goto begin;
if (obj->key != key) { // not the object we expected
put_ref(obj);
goto begin;
}
goto out;
}
/*
* if the nulls value we got at the end of this lookup is
* not the expected one, we must restart lookup.
* We probably met an item that was moved to another chain.
*/
if (get_nulls_value(node) != slot)
goto begin;
obj = NULL;
out:
rcu_read_unlock();
2) Insert function :
--------------------
/*
* Please note that new inserts are done at the head of list,
* not in the middle or end.
*/
obj = kmem_cache_alloc(cachep);
lock_chain(); // typically a spin_lock()
obj->key = key;
atomic_set(&obj->refcnt, 1);
/*
* insert obj in RCU way (readers might be traversing chain)
*/
hlist_nulls_add_head_rcu(&obj->obj_node, list);
unlock_chain(); // typically a spin_unlock()

413
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CONFIG_RCU_TRACE debugfs Files and Formats
The rcupreempt and rcutree implementations of RCU provide debugfs trace
output that summarizes counters and state. This information is useful for
debugging RCU itself, and can sometimes also help to debug abuses of RCU.
Note that the rcuclassic implementation of RCU does not provide debugfs
trace output.
The following sections describe the debugfs files and formats for
preemptable RCU (rcupreempt) and hierarchical RCU (rcutree).
Preemptable RCU debugfs Files and Formats
This implementation of RCU provides three debugfs files under the
top-level directory RCU: rcu/rcuctrs (which displays the per-CPU
counters used by preemptable RCU) rcu/rcugp (which displays grace-period
counters), and rcu/rcustats (which internal counters for debugging RCU).
The output of "cat rcu/rcuctrs" looks as follows:
CPU last cur F M
0 5 -5 0 0
1 -1 0 0 0
2 0 1 0 0
3 0 1 0 0
4 0 1 0 0
5 0 1 0 0
6 0 2 0 0
7 0 -1 0 0
8 0 1 0 0
ggp = 26226, state = waitzero
The per-CPU fields are as follows:
o "CPU" gives the CPU number. Offline CPUs are not displayed.
o "last" gives the value of the counter that is being decremented
for the current grace period phase. In the example above,
the counters sum to 4, indicating that there are still four
RCU read-side critical sections still running that started
before the last counter flip.
o "cur" gives the value of the counter that is currently being
both incremented (by rcu_read_lock()) and decremented (by
rcu_read_unlock()). In the example above, the counters sum to
1, indicating that there is only one RCU read-side critical section
still running that started after the last counter flip.
o "F" indicates whether RCU is waiting for this CPU to acknowledge
a counter flip. In the above example, RCU is not waiting on any,
which is consistent with the state being "waitzero" rather than
"waitack".
o "M" indicates whether RCU is waiting for this CPU to execute a
memory barrier. In the above example, RCU is not waiting on any,
which is consistent with the state being "waitzero" rather than
"waitmb".
o "ggp" is the global grace-period counter.
o "state" is the RCU state, which can be one of the following:
o "idle": there is no grace period in progress.
o "waitack": RCU just incremented the global grace-period
counter, which has the effect of reversing the roles of
the "last" and "cur" counters above, and is waiting for
all the CPUs to acknowledge the flip. Once the flip has
been acknowledged, CPUs will no longer be incrementing
what are now the "last" counters, so that their sum will
decrease monotonically down to zero.
o "waitzero": RCU is waiting for the sum of the "last" counters
to decrease to zero.
o "waitmb": RCU is waiting for each CPU to execute a memory
barrier, which ensures that instructions from a given CPU's
last RCU read-side critical section cannot be reordered
with instructions following the memory-barrier instruction.
The output of "cat rcu/rcugp" looks as follows:
oldggp=48870 newggp=48873
Note that reading from this file provokes a synchronize_rcu(). The
"oldggp" value is that of "ggp" from rcu/rcuctrs above, taken before
executing the synchronize_rcu(), and the "newggp" value is also the
"ggp" value, but taken after the synchronize_rcu() command returns.
The output of "cat rcu/rcugp" looks as follows:
na=1337955 nl=40 wa=1337915 wl=44 da=1337871 dl=0 dr=1337871 di=1337871
1=50989 e1=6138 i1=49722 ie1=82 g1=49640 a1=315203 ae1=265563 a2=49640
z1=1401244 ze1=1351605 z2=49639 m1=5661253 me1=5611614 m2=49639
These are counters tracking internal preemptable-RCU events, however,
some of them may be useful for debugging algorithms using RCU. In
particular, the "nl", "wl", and "dl" values track the number of RCU
callbacks in various states. The fields are as follows:
o "na" is the total number of RCU callbacks that have been enqueued
since boot.
o "nl" is the number of RCU callbacks waiting for the previous
grace period to end so that they can start waiting on the next
grace period.
o "wa" is the total number of RCU callbacks that have started waiting
for a grace period since boot. "na" should be roughly equal to
"nl" plus "wa".
o "wl" is the number of RCU callbacks currently waiting for their
grace period to end.
o "da" is the total number of RCU callbacks whose grace periods
have completed since boot. "wa" should be roughly equal to
"wl" plus "da".
o "dr" is the total number of RCU callbacks that have been removed
from the list of callbacks ready to invoke. "dr" should be roughly
equal to "da".
o "di" is the total number of RCU callbacks that have been invoked
since boot. "di" should be roughly equal to "da", though some
early versions of preemptable RCU had a bug so that only the
last CPU's count of invocations was displayed, rather than the
sum of all CPU's counts.
o "1" is the number of calls to rcu_try_flip(). This should be
roughly equal to the sum of "e1", "i1", "a1", "z1", and "m1"
described below. In other words, the number of times that
the state machine is visited should be equal to the sum of the
number of times that each state is visited plus the number of
times that the state-machine lock acquisition failed.
o "e1" is the number of times that rcu_try_flip() was unable to
acquire the fliplock.
o "i1" is the number of calls to rcu_try_flip_idle().
o "ie1" is the number of times rcu_try_flip_idle() exited early
due to the calling CPU having no work for RCU.
o "g1" is the number of times that rcu_try_flip_idle() decided
to start a new grace period. "i1" should be roughly equal to
"ie1" plus "g1".
o "a1" is the number of calls to rcu_try_flip_waitack().
o "ae1" is the number of times that rcu_try_flip_waitack() found
that at least one CPU had not yet acknowledge the new grace period
(AKA "counter flip").
o "a2" is the number of time rcu_try_flip_waitack() found that
all CPUs had acknowledged. "a1" should be roughly equal to
"ae1" plus "a2". (This particular output was collected on
a 128-CPU machine, hence the smaller-than-usual fraction of
calls to rcu_try_flip_waitack() finding all CPUs having already
acknowledged.)
o "z1" is the number of calls to rcu_try_flip_waitzero().
o "ze1" is the number of times that rcu_try_flip_waitzero() found
that not all of the old RCU read-side critical sections had
completed.
o "z2" is the number of times that rcu_try_flip_waitzero() finds
the sum of the counters equal to zero, in other words, that
all of the old RCU read-side critical sections had completed.
The value of "z1" should be roughly equal to "ze1" plus
"z2".
o "m1" is the number of calls to rcu_try_flip_waitmb().
o "me1" is the number of times that rcu_try_flip_waitmb() finds
that at least one CPU has not yet executed a memory barrier.
o "m2" is the number of times that rcu_try_flip_waitmb() finds that
all CPUs have executed a memory barrier.
Hierarchical RCU debugfs Files and Formats
This implementation of RCU provides three debugfs files under the
top-level directory RCU: rcu/rcudata (which displays fields in struct
rcu_data), rcu/rcugp (which displays grace-period counters), and
rcu/rcuhier (which displays the struct rcu_node hierarchy).
The output of "cat rcu/rcudata" looks as follows:
rcu:
0 c=4011 g=4012 pq=1 pqc=4011 qp=0 rpfq=1 rp=3c2a dt=23301/73 dn=2 df=1882 of=0 ri=2126 ql=2 b=10
1 c=4011 g=4012 pq=1 pqc=4011 qp=0 rpfq=3 rp=39a6 dt=78073/1 dn=2 df=1402 of=0 ri=1875 ql=46 b=10
2 c=4010 g=4010 pq=1 pqc=4010 qp=0 rpfq=-5 rp=1d12 dt=16646/0 dn=2 df=3140 of=0 ri=2080 ql=0 b=10
3 c=4012 g=4013 pq=1 pqc=4012 qp=1 rpfq=3 rp=2b50 dt=21159/1 dn=2 df=2230 of=0 ri=1923 ql=72 b=10
4 c=4012 g=4013 pq=1 pqc=4012 qp=1 rpfq=3 rp=1644 dt=5783/1 dn=2 df=3348 of=0 ri=2805 ql=7 b=10
5 c=4012 g=4013 pq=0 pqc=4011 qp=1 rpfq=3 rp=1aac dt=5879/1 dn=2 df=3140 of=0 ri=2066 ql=10 b=10
6 c=4012 g=4013 pq=1 pqc=4012 qp=1 rpfq=3 rp=ed8 dt=5847/1 dn=2 df=3797 of=0 ri=1266 ql=10 b=10
7 c=4012 g=4013 pq=1 pqc=4012 qp=1 rpfq=3 rp=1fa2 dt=6199/1 dn=2 df=2795 of=0 ri=2162 ql=28 b=10
rcu_bh:
0 c=-268 g=-268 pq=1 pqc=-268 qp=0 rpfq=-145 rp=21d6 dt=23301/73 dn=2 df=0 of=0 ri=0 ql=0 b=10
1 c=-268 g=-268 pq=1 pqc=-268 qp=1 rpfq=-170 rp=20ce dt=78073/1 dn=2 df=26 of=0 ri=5 ql=0 b=10
2 c=-268 g=-268 pq=1 pqc=-268 qp=1 rpfq=-83 rp=fbd dt=16646/0 dn=2 df=28 of=0 ri=4 ql=0 b=10
3 c=-268 g=-268 pq=1 pqc=-268 qp=0 rpfq=-105 rp=178c dt=21159/1 dn=2 df=28 of=0 ri=2 ql=0 b=10
4 c=-268 g=-268 pq=1 pqc=-268 qp=1 rpfq=-30 rp=b54 dt=5783/1 dn=2 df=32 of=0 ri=0 ql=0 b=10
5 c=-268 g=-268 pq=1 pqc=-268 qp=1 rpfq=-29 rp=df5 dt=5879/1 dn=2 df=30 of=0 ri=3 ql=0 b=10
6 c=-268 g=-268 pq=1 pqc=-268 qp=1 rpfq=-28 rp=788 dt=5847/1 dn=2 df=32 of=0 ri=0 ql=0 b=10
7 c=-268 g=-268 pq=1 pqc=-268 qp=1 rpfq=-53 rp=1098 dt=6199/1 dn=2 df=30 of=0 ri=3 ql=0 b=10
The first section lists the rcu_data structures for rcu, the second for
rcu_bh. Each section has one line per CPU, or eight for this 8-CPU system.
The fields are as follows:
o The number at the beginning of each line is the CPU number.
CPUs numbers followed by an exclamation mark are offline,
but have been online at least once since boot. There will be
no output for CPUs that have never been online, which can be
a good thing in the surprisingly common case where NR_CPUS is
substantially larger than the number of actual CPUs.
o "c" is the count of grace periods that this CPU believes have
completed. CPUs in dynticks idle mode may lag quite a ways
behind, for example, CPU 4 under "rcu" above, which has slept
through the past 25 RCU grace periods. It is not unusual to
see CPUs lagging by thousands of grace periods.
o "g" is the count of grace periods that this CPU believes have
started. Again, CPUs in dynticks idle mode may lag behind.
If the "c" and "g" values are equal, this CPU has already
reported a quiescent state for the last RCU grace period that
it is aware of, otherwise, the CPU believes that it owes RCU a
quiescent state.
o "pq" indicates that this CPU has passed through a quiescent state
for the current grace period. It is possible for "pq" to be
"1" and "c" different than "g", which indicates that although
the CPU has passed through a quiescent state, either (1) this
CPU has not yet reported that fact, (2) some other CPU has not
yet reported for this grace period, or (3) both.
o "pqc" indicates which grace period the last-observed quiescent
state for this CPU corresponds to. This is important for handling
the race between CPU 0 reporting an extended dynticks-idle
quiescent state for CPU 1 and CPU 1 suddenly waking up and
reporting its own quiescent state. If CPU 1 was the last CPU
for the current grace period, then the CPU that loses this race
will attempt to incorrectly mark CPU 1 as having checked in for
the next grace period!
o "qp" indicates that RCU still expects a quiescent state from
this CPU.
o "rpfq" is the number of rcu_pending() calls on this CPU required
to induce this CPU to invoke force_quiescent_state().
o "rp" is low-order four hex digits of the count of how many times
rcu_pending() has been invoked on this CPU.
o "dt" is the current value of the dyntick counter that is incremented
when entering or leaving dynticks idle state, either by the
scheduler or by irq. The number after the "/" is the interrupt
nesting depth when in dyntick-idle state, or one greater than
the interrupt-nesting depth otherwise.
This field is displayed only for CONFIG_NO_HZ kernels.
o "dn" is the current value of the dyntick counter that is incremented
when entering or leaving dynticks idle state via NMI. If both
the "dt" and "dn" values are even, then this CPU is in dynticks
idle mode and may be ignored by RCU. If either of these two
counters is odd, then RCU must be alert to the possibility of
an RCU read-side critical section running on this CPU.
This field is displayed only for CONFIG_NO_HZ kernels.
o "df" is the number of times that some other CPU has forced a
quiescent state on behalf of this CPU due to this CPU being in
dynticks-idle state.
This field is displayed only for CONFIG_NO_HZ kernels.
o "of" is the number of times that some other CPU has forced a
quiescent state on behalf of this CPU due to this CPU being
offline. In a perfect world, this might neve happen, but it
turns out that offlining and onlining a CPU can take several grace
periods, and so there is likely to be an extended period of time
when RCU believes that the CPU is online when it really is not.
Please note that erring in the other direction (RCU believing a
CPU is offline when it is really alive and kicking) is a fatal
error, so it makes sense to err conservatively.
o "ri" is the number of times that RCU has seen fit to send a
reschedule IPI to this CPU in order to get it to report a
quiescent state.
o "ql" is the number of RCU callbacks currently residing on
this CPU. This is the total number of callbacks, regardless
of what state they are in (new, waiting for grace period to
start, waiting for grace period to end, ready to invoke).
o "b" is the batch limit for this CPU. If more than this number
of RCU callbacks is ready to invoke, then the remainder will
be deferred.
The output of "cat rcu/rcugp" looks as follows:
rcu: completed=33062 gpnum=33063
rcu_bh: completed=464 gpnum=464
Again, this output is for both "rcu" and "rcu_bh". The fields are
taken from the rcu_state structure, and are as follows:
o "completed" is the number of grace periods that have completed.
It is comparable to the "c" field from rcu/rcudata in that a
CPU whose "c" field matches the value of "completed" is aware
that the corresponding RCU grace period has completed.
o "gpnum" is the number of grace periods that have started. It is
comparable to the "g" field from rcu/rcudata in that a CPU
whose "g" field matches the value of "gpnum" is aware that the
corresponding RCU grace period has started.
If these two fields are equal (as they are for "rcu_bh" above),
then there is no grace period in progress, in other words, RCU
is idle. On the other hand, if the two fields differ (as they
do for "rcu" above), then an RCU grace period is in progress.
The output of "cat rcu/rcuhier" looks as follows, with very long lines:
c=6902 g=6903 s=2 jfq=3 j=72c7 nfqs=13142/nfqsng=0(13142) fqlh=6
1/1 0:127 ^0
3/3 0:35 ^0 0/0 36:71 ^1 0/0 72:107 ^2 0/0 108:127 ^3
3/3f 0:5 ^0 2/3 6:11 ^1 0/0 12:17 ^2 0/0 18:23 ^3 0/0 24:29 ^4 0/0 30:35 ^5 0/0 36:41 ^0 0/0 42:47 ^1 0/0 48:53 ^2 0/0 54:59 ^3 0/0 60:65 ^4 0/0 66:71 ^5 0/0 72:77 ^0 0/0 78:83 ^1 0/0 84:89 ^2 0/0 90:95 ^3 0/0 96:101 ^4 0/0 102:107 ^5 0/0 108:113 ^0 0/0 114:119 ^1 0/0 120:125 ^2 0/0 126:127 ^3
rcu_bh:
c=-226 g=-226 s=1 jfq=-5701 j=72c7 nfqs=88/nfqsng=0(88) fqlh=0
0/1 0:127 ^0
0/3 0:35 ^0 0/0 36:71 ^1 0/0 72:107 ^2 0/0 108:127 ^3
0/3f 0:5 ^0 0/3 6:11 ^1 0/0 12:17 ^2 0/0 18:23 ^3 0/0 24:29 ^4 0/0 30:35 ^5 0/0 36:41 ^0 0/0 42:47 ^1 0/0 48:53 ^2 0/0 54:59 ^3 0/0 60:65 ^4 0/0 66:71 ^5 0/0 72:77 ^0 0/0 78:83 ^1 0/0 84:89 ^2 0/0 90:95 ^3 0/0 96:101 ^4 0/0 102:107 ^5 0/0 108:113 ^0 0/0 114:119 ^1 0/0 120:125 ^2 0/0 126:127 ^3
This is once again split into "rcu" and "rcu_bh" portions. The fields are
as follows:
o "c" is exactly the same as "completed" under rcu/rcugp.
o "g" is exactly the same as "gpnum" under rcu/rcugp.
o "s" is the "signaled" state that drives force_quiescent_state()'s
state machine.
o "jfq" is the number of jiffies remaining for this grace period
before force_quiescent_state() is invoked to help push things
along. Note that CPUs in dyntick-idle mode thoughout the grace
period will not report on their own, but rather must be check by
some other CPU via force_quiescent_state().
o "j" is the low-order four hex digits of the jiffies counter.
Yes, Paul did run into a number of problems that turned out to
be due to the jiffies counter no longer counting. Why do you ask?
o "nfqs" is the number of calls to force_quiescent_state() since
boot.
o "nfqsng" is the number of useless calls to force_quiescent_state(),
where there wasn't actually a grace period active. This can
happen due to races. The number in parentheses is the difference
between "nfqs" and "nfqsng", or the number of times that
force_quiescent_state() actually did some real work.
o "fqlh" is the number of calls to force_quiescent_state() that
exited immediately (without even being counted in nfqs above)
due to contention on ->fqslock.
o Each element of the form "1/1 0:127 ^0" represents one struct
rcu_node. Each line represents one level of the hierarchy, from
root to leaves. It is best to think of the rcu_data structures
as forming yet another level after the leaves. Note that there
might be either one, two, or three levels of rcu_node structures,
depending on the relationship between CONFIG_RCU_FANOUT and
CONFIG_NR_CPUS.
o The numbers separated by the "/" are the qsmask followed
by the qsmaskinit. The qsmask will have one bit
set for each entity in the next lower level that
has not yet checked in for the current grace period.
The qsmaskinit will have one bit for each entity that is
currently expected to check in during each grace period.
The value of qsmaskinit is assigned to that of qsmask
at the beginning of each grace period.
For example, for "rcu", the qsmask of the first entry
of the lowest level is 0x14, meaning that we are still
waiting for CPUs 2 and 4 to check in for the current
grace period.
o The numbers separated by the ":" are the range of CPUs
served by this struct rcu_node. This can be helpful
in working out how the hierarchy is wired together.
For example, the first entry at the lowest level shows
"0:5", indicating that it covers CPUs 0 through 5.
o The number after the "^" indicates the bit in the
next higher level rcu_node structure that this
rcu_node structure corresponds to.
For example, the first entry at the lowest level shows
"^0", indicating that it corresponds to bit zero in
the first entry at the middle level.

4
Documentation/accounting/getdelays.c
View File

@ -392,6 +392,10 @@ int main(int argc, char *argv[])
goto err;
}
}
if (!maskset && !tid && !containerset) {
usage();
goto err;
}
do {
int i;

286
Documentation/arm/pxa/mfp.txt Normal file
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@ -0,0 +1,286 @@
MFP Configuration for PXA2xx/PXA3xx Processors
Eric Miao <eric.miao@marvell.com>
MFP stands for Multi-Function Pin, which is the pin-mux logic on PXA3xx and
later PXA series processors. This document describes the existing MFP API,
and how board/platform driver authors could make use of it.
Basic Concept
===============
Unlike the GPIO alternate function settings on PXA25x and PXA27x, a new MFP
mechanism is introduced from PXA3xx to completely move the pin-mux functions
out of the GPIO controller. In addition to pin-mux configurations, the MFP
also controls the low power state, driving strength, pull-up/down and event
detection of each pin. Below is a diagram of internal connections between
the MFP logic and the remaining SoC peripherals:
+--------+
| |--(GPIO19)--+
| GPIO | |
| |--(GPIO...) |
+--------+ |
| +---------+
+--------+ +------>| |
| PWM2 |--(PWM_OUT)-------->| MFP |
+--------+ +------>| |-------> to external PAD
| +---->| |
+--------+ | | +-->| |
| SSP2 |---(TXD)----+ | | +---------+
+--------+ | |
| |
+--------+ | |
| Keypad |--(MKOUT4)----+ |
+--------+ |
|
+--------+ |
| UART2 |---(TXD)--------+
+--------+
NOTE: the external pad is named as MFP_PIN_GPIO19, it doesn't necessarily
mean it's dedicated for GPIO19, only as a hint that internally this pin
can be routed from GPIO19 of the GPIO controller.
To better understand the change from PXA25x/PXA27x GPIO alternate function
to this new MFP mechanism, here are several key points:
1. GPIO controller on PXA3xx is now a dedicated controller, same as other
internal controllers like PWM, SSP and UART, with 128 internal signals
which can be routed to external through one or more MFPs (e.g. GPIO<0>
can be routed through either MFP_PIN_GPIO0 as well as MFP_PIN_GPIO0_2,
see arch/arm/mach-pxa/mach/include/mfp-pxa300.h)
2. Alternate function configuration is removed from this GPIO controller,
the remaining functions are pure GPIO-specific, i.e.
- GPIO signal level control
- GPIO direction control
- GPIO level change detection
3. Low power state for each pin is now controlled by MFP, this means the
PGSRx registers on PXA2xx are now useless on PXA3xx
4. Wakeup detection is now controlled by MFP, PWER does not control the
wakeup from GPIO(s) any more, depending on the sleeping state, ADxER
(as defined in pxa3xx-regs.h) controls the wakeup from MFP
NOTE: with such a clear separation of MFP and GPIO, by GPIO<xx> we normally
mean it is a GPIO signal, and by MFP<xxx> or pin xxx, we mean a physical
pad (or ball).
MFP API Usage
===============
For board code writers, here are some guidelines:
1. include ONE of the following header files in your <board>.c:
- #include <mach/mfp-pxa25x.h>
- #include <mach/mfp-pxa27x.h>
- #include <mach/mfp-pxa300.h>
- #include <mach/mfp-pxa320.h>
- #include <mach/mfp-pxa930.h>
NOTE: only one file in your <board>.c, depending on the processors used,
because pin configuration definitions may conflict in these file (i.e.
same name, different meaning and settings on different processors). E.g.
for zylonite platform, which support both PXA300/PXA310 and PXA320, two
separate files are introduced: zylonite_pxa300.c and zylonite_pxa320.c
(in addition to handle MFP configuration differences, they also handle
the other differences between the two combinations).
NOTE: PXA300 and PXA310 are almost identical in pin configurations (with
PXA310 supporting some additional ones), thus the difference is actually
covered in a single mfp-pxa300.h.
2. prepare an array for the initial pin configurations, e.g.:
static unsigned long mainstone_pin_config[] __initdata = {
/* Chip Select */
GPIO15_nCS_1,
/* LCD - 16bpp Active TFT */
GPIOxx_TFT_LCD_16BPP,
GPIO16_PWM0_OUT, /* Backlight */
/* MMC */
GPIO32_MMC_CLK,
GPIO112_MMC_CMD,
GPIO92_MMC_DAT_0,
GPIO109_MMC_DAT_1,
GPIO110_MMC_DAT_2,
GPIO111_MMC_DAT_3,
...
/* GPIO */
GPIO1_GPIO | WAKEUP_ON_EDGE_BOTH,
};
a) once the pin configurations are passed to pxa{2xx,3xx}_mfp_config(),
and written to the actual registers, they are useless and may discard,
adding '__initdata' will help save some additional bytes here.
b) when there is only one possible pin configurations for a component,
some simplified definitions can be used, e.g. GPIOxx_TFT_LCD_16BPP on
PXA25x and PXA27x processors
c) if by board design, a pin can be configured to wake up the system
from low power state, it can be 'OR'ed with any of:
WAKEUP_ON_EDGE_BOTH
WAKEUP_ON_EDGE_RISE
WAKEUP_ON_EDGE_FALL
WAKEUP_ON_LEVEL_HIGH - specifically for enabling of keypad GPIOs,
to indicate that this pin has the capability of wake-up the system,
and on which edge(s). This, however, doesn't necessarily mean the
pin _will_ wakeup the system, it will only when set_irq_wake() is
invoked with the corresponding GPIO IRQ (GPIO_IRQ(xx) or gpio_to_irq())
and eventually calls gpio_set_wake() for the actual register setting.
d) although PXA3xx MFP supports edge detection on each pin, the
internal logic will only wakeup the system when those specific bits
in ADxER registers are set, which can be well mapped to the
corresponding peripheral, thus set_irq_wake() can be called with
the peripheral IRQ to enable the wakeup.
MFP on PXA3xx
===============
Every external I/O pad on PXA3xx (excluding those for special purpose) has
one MFP logic associated, and is controlled by one MFP register (MFPR).
The MFPR has the following bit definitions (for PXA300/PXA310/PXA320):
31 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
+-------------------------+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
| RESERVED |PS|PU|PD| DRIVE |SS|SD|SO|EC|EF|ER|--| AF_SEL |
+-------------------------+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
Bit 3: RESERVED
Bit 4: EDGE_RISE_EN - enable detection of rising edge on this pin
Bit 5: EDGE_FALL_EN - enable detection of falling edge on this pin
Bit 6: EDGE_CLEAR - disable edge detection on this pin
Bit 7: SLEEP_OE_N - enable outputs during low power modes
Bit 8: SLEEP_DATA - output data on the pin during low power modes
Bit 9: SLEEP_SEL - selection control for low power modes signals
Bit 13: PULLDOWN_EN - enable the internal pull-down resistor on this pin
Bit 14: PULLUP_EN - enable the internal pull-up resistor on this pin
Bit 15: PULL_SEL - pull state controlled by selected alternate function
(0) or by PULL{UP,DOWN}_EN bits (1)
Bit 0 - 2: AF_SEL - alternate function selection, 8 possibilities, from 0-7
Bit 10-12: DRIVE - drive strength and slew rate
0b000 - fast 1mA
0b001 - fast 2mA
0b002 - fast 3mA
0b003 - fast 4mA
0b004 - slow 6mA
0b005 - fast 6mA
0b006 - slow 10mA
0b007 - fast 10mA
MFP Design for PXA2xx/PXA3xx
==============================
Due to the difference of pin-mux handling between PXA2xx and PXA3xx, a unified
MFP API is introduced to cover both series of processors.
The basic idea of this design is to introduce definitions for all possible pin
configurations, these definitions are processor and platform independent, and
the actual API invoked to convert these definitions into register settings and
make them effective there-after.
Files Involved
--------------
- arch/arm/mach-pxa/include/mach/mfp.h
for
1. Unified pin definitions - enum constants for all configurable pins
2. processor-neutral bit definitions for a possible MFP configuration
- arch/arm/mach-pxa/include/mach/mfp-pxa3xx.h
for PXA3xx specific MFPR register bit definitions and PXA3xx common pin
configurations
- arch/arm/mach-pxa/include/mach/mfp-pxa2xx.h
for PXA2xx specific definitions and PXA25x/PXA27x common pin configurations
- arch/arm/mach-pxa/include/mach/mfp-pxa25x.h
arch/arm/mach-pxa/include/mach/mfp-pxa27x.h
arch/arm/mach-pxa/include/mach/mfp-pxa300.h
arch/arm/mach-pxa/include/mach/mfp-pxa320.h
arch/arm/mach-pxa/include/mach/mfp-pxa930.h
for processor specific definitions
- arch/arm/mach-pxa/mfp-pxa3xx.c
- arch/arm/mach-pxa/mfp-pxa2xx.c
for implementation of the pin configuration to take effect for the actual
processor.
Pin Configuration
-----------------
The following comments are copied from mfp.h (see the actual source code
for most updated info)
/*
* a possible MFP configuration is represented by a 32-bit integer
*
* bit 0.. 9 - MFP Pin Number (1024 Pins Maximum)
* bit 10..12 - Alternate Function Selection
* bit 13..15 - Drive Strength
* bit 16..18 - Low Power Mode State
* bit 19..20 - Low Power Mode Edge Detection
* bit 21..22 - Run Mode Pull State
*
* to facilitate the definition, the following macros are provided
*
* MFP_CFG_DEFAULT - default MFP configuration value, with
* alternate function = 0,
* drive strength = fast 3mA (MFP_DS03X)
* low power mode = default
* edge detection = none
*
* MFP_CFG - default MFPR value with alternate function
* MFP_CFG_DRV - default MFPR value with alternate function and
* pin drive strength
* MFP_CFG_LPM - default MFPR value with alternate function and
* low power mode
* MFP_CFG_X - default MFPR value with alternate function,
* pin drive strength and low power mode
*/
Examples of pin configurations are:
#define GPIO94_SSP3_RXD MFP_CFG_X(GPIO94, AF1, DS08X, FLOAT)
which reads GPIO94 can be configured as SSP3_RXD, with alternate function
selection of 1, driving strength of 0b101, and a float state in low power
modes.
NOTE: this is the default setting of this pin being configured as SSP3_RXD
which can be modified a bit in board code, though it is not recommended to
do so, simply because this default setting is usually carefully encoded,
and is supposed to work in most cases.
Register Settings
-----------------
Register settings on PXA3xx for a pin configuration is actually very
straight-forward, most bits can be converted directly into MFPR value
in a easier way. Two sets of MFPR values are calculated: the run-time
ones and the low power mode ones, to allow different settings.
The conversion from a generic pin configuration to the actual register
settings on PXA2xx is a bit complicated: many registers are involved,
including GAFRx, GPDRx, PGSRx, PWER, PKWR, PFER and PRER. Please see
mfp-pxa2xx.c for how the conversion is made.

45
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@ -0,0 +1,45 @@
March 2008
Jan-Simon Moeller, dl9pf@gmx.de
How to deal with bad memory e.g. reported by memtest86+ ?
#########################################################
There are three possibilities I know of:
1) Reinsert/swap the memory modules
2) Buy new modules (best!) or try to exchange the memory
if you have spare-parts
3) Use BadRAM or memmap
This Howto is about number 3) .
BadRAM
######
BadRAM is the actively developed and available as kernel-patch
here: http://rick.vanrein.org/linux/badram/
For more details see the BadRAM documentation.
memmap
######
memmap is already in the kernel and usable as kernel-parameter at
boot-time. Its syntax is slightly strange and you may need to
calculate the values by yourself!
Syntax to exclude a memory area (see kernel-parameters.txt for details):
memmap=<size>$<address>
Example: memtest86+ reported here errors at address 0x18691458, 0x18698424 and
some others. All had 0x1869xxxx in common, so I chose a pattern of
0x18690000,0xffff0000.
With the numbers of the example above:
memmap=64K$0x18690000
or
memmap=0x10000$0x18690000

3
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@ -9,3 +9,6 @@ cachefeatures.txt
Filesystems
- Requirements for mounting the root file system.
bfin-gpio-note.txt
- Notes in developing/using bfin-gpio driver.

71
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@ -0,0 +1,71 @@
/*
* File: Documentation/blackfin/bfin-gpio-note.txt
* Based on:
* Author:
*
* Created: $Id: bfin-gpio-note.txt 2008-11-24 16:42 grafyang $
* Description: This file contains the notes in developing/using bfin-gpio.
*
*
* Rev:
*
* Modified:
* Copyright 2004-2008 Analog Devices Inc.
*
* Bugs: Enter bugs at http://blackfin.uclinux.org/
*
*/
1. Blackfin GPIO introduction
There are many GPIO pins on Blackfin. Most of these pins are muxed to
multi-functions. They can be configured as peripheral, or just as GPIO,
configured to input with interrupt enabled, or output.
For detailed information, please see "arch/blackfin/kernel/bfin_gpio.c",
or the relevant HRM.
2. Avoiding resource conflict
Followed function groups are used to avoiding resource conflict,
- Use the pin as peripheral,
int peripheral_request(unsigned short per, const char *label);
int peripheral_request_list(const unsigned short per[], const char *label);
void peripheral_free(unsigned short per);
void peripheral_free_list(const unsigned short per[]);
- Use the pin as GPIO,
int bfin_gpio_request(unsigned gpio, const char *label);
void bfin_gpio_free(unsigned gpio);
- Use the pin as GPIO interrupt,
int bfin_gpio_irq_request(unsigned gpio, const char *label);
void bfin_gpio_irq_free(unsigned gpio);
The request functions will record the function state for a certain pin,
the free functions will clear it's function state.
Once a pin is requested, it can't be requested again before it is freed by
previous caller, otherwise kernel will dump stacks, and the request
function fail.
These functions are wrapped by other functions, most of the users need not
care.
3. But there are some exceptions
- Kernel permit the identical GPIO be requested both as GPIO and GPIO
interrut.
Some drivers, like gpio-keys, need this behavior. Kernel only print out
warning messages like,
bfin-gpio: GPIO 24 is already reserved by gpio-keys: BTN0, and you are
configuring it as IRQ!
Note: Consider the case that, if there are two drivers need the
identical GPIO, one of them use it as GPIO, the other use it as
GPIO interrupt. This will really cause resource conflict. So if
there is any abnormal driver behavior, please check the bfin-gpio
warning messages.
- Kernel permit the identical GPIO be requested from the same driver twice.

6
Documentation/block/biodoc.txt
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@ -914,7 +914,7 @@ I/O scheduler, a.k.a. elevator, is implemented in two layers. Generic dispatch
queue and specific I/O schedulers. Unless stated otherwise, elevator is used
to refer to both parts and I/O scheduler to specific I/O schedulers.
Block layer implements generic dispatch queue in ll_rw_blk.c and elevator.c.
Block layer implements generic dispatch queue in block/*.c.
The generic dispatch queue is responsible for properly ordering barrier
requests, requeueing, handling non-fs requests and all other subtleties.
@ -926,8 +926,8 @@ be built inside the kernel. Each queue can choose different one and can also
change to another one dynamically.
A block layer call to the i/o scheduler follows the convention elv_xxx(). This
calls elevator_xxx_fn in the elevator switch (drivers/block/elevator.c). Oh,
xxx and xxx might not match exactly, but use your imagination. If an elevator
calls elevator_xxx_fn in the elevator switch (block/elevator.c). Oh, xxx
and xxx might not match exactly, but use your imagination. If an elevator
doesn't implement a function, the switch does nothing or some minimal house
keeping work.

14
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@ -1,7 +1,8 @@
CGROUPS
-------
Written by Paul Menage <menage@google.com> based on Documentation/cpusets.txt
Written by Paul Menage <menage@google.com> based on
Documentation/cgroups/cpusets.txt
Original copyright statements from cpusets.txt:
Portions Copyright (C) 2004 BULL SA.
@ -68,7 +69,7 @@ On their own, the only use for cgroups is for simple job
tracking. The intention is that other subsystems hook into the generic
cgroup support to provide new attributes for cgroups, such as
accounting/limiting the resources which processes in a cgroup can
access. For example, cpusets (see Documentation/cpusets.txt) allows
access. For example, cpusets (see Documentation/cgroups/cpusets.txt) allows
you to associate a set of CPUs and a set of memory nodes with the
tasks in each cgroup.
@ -227,7 +228,6 @@ Each cgroup is represented by a directory in the cgroup file system
containing the following files describing that cgroup:
- tasks: list of tasks (by pid) attached to that cgroup
- releasable flag: cgroup currently removeable?
- notify_on_release flag: run the release agent on exit?
- release_agent: the path to use for release notifications (this file
exists in the top cgroup only)
@ -360,7 +360,7 @@ Now you want to do something with this cgroup.
In this directory you can find several files:
# ls
notify_on_release releasable tasks
notify_on_release tasks
(plus whatever files added by the attached subsystems)
Now attach your shell to this cgroup:
@ -479,7 +479,6 @@ newly-created cgroup if an error occurs after this subsystem's
create() method has been called for the new cgroup).
void pre_destroy(struct cgroup_subsys *ss, struct cgroup *cgrp);
(cgroup_mutex held by caller)
Called before checking the reference count on each subsystem. This may
be useful for subsystems which have some extra references even if
@ -498,6 +497,7 @@ remain valid while the caller holds cgroup_mutex.
void attach(struct cgroup_subsys *ss, struct cgroup *cgrp,
struct cgroup *old_cgrp, struct task_struct *task)
(cgroup_mutex held by caller)
Called after the task has been attached to the cgroup, to allow any
post-attachment activity that requires memory allocations or blocking.
@ -511,6 +511,7 @@ void exit(struct cgroup_subsys *ss, struct task_struct *task)
Called during task exit.
int populate(struct cgroup_subsys *ss, struct cgroup *cgrp)
(cgroup_mutex held by caller)
Called after creation of a cgroup to allow a subsystem to populate
the cgroup directory with file entries. The subsystem should make
@ -520,6 +521,7 @@ method can return an error code, the error code is currently not
always handled well.
void post_clone(struct cgroup_subsys *ss, struct cgroup *cgrp)
(cgroup_mutex held by caller)
Called at the end of cgroup_clone() to do any paramater
initialization which might be required before a task could attach. For
@ -527,7 +529,7 @@ example in cpusets, no task may attach before 'cpus' and 'mems' are set
up.
void bind(struct cgroup_subsys *ss, struct cgroup *root)
(cgroup_mutex held by caller)
(cgroup_mutex and ss->hierarchy_mutex held by caller)
Called when a cgroup subsystem is rebound to a different hierarchy
and root cgroup. Currently this will only involve movement between

32
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@ -0,0 +1,32 @@
CPU Accounting Controller
-------------------------
The CPU accounting controller is used to group tasks using cgroups and
account the CPU usage of these groups of tasks.
The CPU accounting controller supports multi-hierarchy groups. An accounting
group accumulates the CPU usage of all of its child groups and the tasks
directly present in its group.
Accounting groups can be created by first mounting the cgroup filesystem.
# mkdir /cgroups
# mount -t cgroup -ocpuacct none /cgroups
With the above step, the initial or the parent accounting group
becomes visible at /cgroups. At bootup, this group includes all the
tasks in the system. /cgroups/tasks lists the tasks in this cgroup.
/cgroups/cpuacct.usage gives the CPU time (in nanoseconds) obtained by
this group which is essentially the CPU time obtained by all the tasks
in the system.
New accounting groups can be created under the parent group /cgroups.
# cd /cgroups
# mkdir g1
# echo $$ > g1
The above steps create a new group g1 and move the current shell
process (bash) into it. CPU time consumed by this bash and its children
can be obtained from g1/cpuacct.usage and the same is accumulated in
/cgroups/cpuacct.usage also.

0
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0
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@ -0,0 +1,342 @@
Memory Resource Controller(Memcg) Implementation Memo.
Last Updated: 2008/12/15
Base Kernel Version: based on 2.6.28-rc8-mm.
Because VM is getting complex (one of reasons is memcg...), memcg's behavior
is complex. This is a document for memcg's internal behavior.
Please note that implementation details can be changed.
(*) Topics on API should be in Documentation/cgroups/memory.txt)
0. How to record usage ?
2 objects are used.
page_cgroup ....an object per page.
Allocated at boot or memory hotplug. Freed at memory hot removal.
swap_cgroup ... an entry per swp_entry.
Allocated at swapon(). Freed at swapoff().
The page_cgroup has USED bit and double count against a page_cgroup never
occurs. swap_cgroup is used only when a charged page is swapped-out.
1. Charge
a page/swp_entry may be charged (usage += PAGE_SIZE) at
mem_cgroup_newpage_charge()
Called at new page fault and Copy-On-Write.
mem_cgroup_try_charge_swapin()
Called at do_swap_page() (page fault on swap entry) and swapoff.
Followed by charge-commit-cancel protocol. (With swap accounting)
At commit, a charge recorded in swap_cgroup is removed.
mem_cgroup_cache_charge()
Called at add_to_page_cache()
mem_cgroup_cache_charge_swapin()
Called at shmem's swapin.
mem_cgroup_prepare_migration()
Called before migration. "extra" charge is done and followed by
charge-commit-cancel protocol.
At commit, charge against oldpage or newpage will be committed.
2. Uncharge
a page/swp_entry may be uncharged (usage -= PAGE_SIZE) by
mem_cgroup_uncharge_page()
Called when an anonymous page is fully unmapped. I.e., mapcount goes
to 0. If the page is SwapCache, uncharge is delayed until
mem_cgroup_uncharge_swapcache().
mem_cgroup_uncharge_cache_page()
Called when a page-cache is deleted from radix-tree. If the page is
SwapCache, uncharge is delayed until mem_cgroup_uncharge_swapcache().
mem_cgroup_uncharge_swapcache()
Called when SwapCache is removed from radix-tree. The charge itself
is moved to swap_cgroup. (If mem+swap controller is disabled, no
charge to swap occurs.)
mem_cgroup_uncharge_swap()
Called when swp_entry's refcnt goes down to 0. A charge against swap
disappears.
mem_cgroup_end_migration(old, new)
At success of migration old is uncharged (if necessary), a charge
to new page is committed. At failure, charge to old page is committed.
3. charge-commit-cancel
In some case, we can't know this "charge" is valid or not at charging
(because of races).
To handle such case, there are charge-commit-cancel functions.
mem_cgroup_try_charge_XXX
mem_cgroup_commit_charge_XXX
mem_cgroup_cancel_charge_XXX
these are used in swap-in and migration.
At try_charge(), there are no flags to say "this page is charged".
at this point, usage += PAGE_SIZE.
At commit(), the function checks the page should be charged or not
and set flags or avoid charging.(usage -= PAGE_SIZE)
At cancel(), simply usage -= PAGE_SIZE.
Under below explanation, we assume CONFIG_MEM_RES_CTRL_SWAP=y.
4. Anonymous
Anonymous page is newly allocated at
- page fault into MAP_ANONYMOUS mapping.
- Copy-On-Write.
It is charged right after it's allocated before doing any page table
related operations. Of course, it's uncharged when another page is used
for the fault address.
At freeing anonymous page (by exit() or munmap()), zap_pte() is called
and pages for ptes are freed one by one.(see mm/memory.c). Uncharges
are done at page_remove_rmap() when page_mapcount() goes down to 0.
Another page freeing is by page-reclaim (vmscan.c) and anonymous
pages are swapped out. In this case, the page is marked as
PageSwapCache(). uncharge() routine doesn't uncharge the page marked
as SwapCache(). It's delayed until __delete_from_swap_cache().
4.1 Swap-in.
At swap-in, the page is taken from swap-cache. There are 2 cases.
(a) If the SwapCache is newly allocated and read, it has no charges.
(b) If the SwapCache has been mapped by processes, it has been
charged already.
This swap-in is one of the most complicated work. In do_swap_page(),
following events occur when pte is unchanged.
(1) the page (SwapCache) is looked up.
(2) lock_page()
(3) try_charge_swapin()
(4) reuse_swap_page() (may call delete_swap_cache())
(5) commit_charge_swapin()
(6) swap_free().
Considering following situation for example.
(A) The page has not been charged before (2) and reuse_swap_page()
doesn't call delete_from_swap_cache().
(B) The page has not been charged before (2) and reuse_swap_page()
calls delete_from_swap_cache().
(C) The page has been charged before (2) and reuse_swap_page() doesn't
call delete_from_swap_cache().
(D) The page has been charged before (2) and reuse_swap_page() calls
delete_from_swap_cache().
memory.usage/memsw.usage changes to this page/swp_entry will be
Case (A) (B) (C) (D)
Event
Before (2) 0/ 1 0/ 1 1/ 1 1/ 1
===========================================
(3) +1/+1 +1/+1 +1/+1 +1/+1
(4) - 0/ 0 - -1/ 0
(5) 0/-1 0/ 0 -1/-1 0/ 0
(6) - 0/-1 - 0/-1
===========================================
Result 1/ 1 1/ 1 1/ 1 1/ 1
In any cases, charges to this page should be 1/ 1.
4.2 Swap-out.
At swap-out, typical state transition is below.
(a) add to swap cache. (marked as SwapCache)
swp_entry's refcnt += 1.
(b) fully unmapped.
swp_entry's refcnt += # of ptes.
(c) write back to swap.
(d) delete from swap cache. (remove from SwapCache)
swp_entry's refcnt -= 1.
At (b), the page is marked as SwapCache and not uncharged.
At (d), the page is removed from SwapCache and a charge in page_cgroup
is moved to swap_cgroup.
Finally, at task exit,
(e) zap_pte() is called and swp_entry's refcnt -=1 -> 0.
Here, a charge in swap_cgroup disappears.
5. Page Cache
Page Cache is charged at
- add_to_page_cache_locked().
uncharged at
- __remove_from_page_cache().
The logic is very clear. (About migration, see below)
Note: __remove_from_page_cache() is called by remove_from_page_cache()
and __remove_mapping().
6. Shmem(tmpfs) Page Cache
Memcg's charge/uncharge have special handlers of shmem. The best way
to understand shmem's page state transition is to read mm/shmem.c.
But brief explanation of the behavior of memcg around shmem will be
helpful to understand the logic.
Shmem's page (just leaf page, not direct/indirect block) can be on
- radix-tree of shmem's inode.
- SwapCache.
- Both on radix-tree and SwapCache. This happens at swap-in
and swap-out,
It's charged when...
- A new page is added to shmem's radix-tree.
- A swp page is read. (move a charge from swap_cgroup to page_cgroup)
It's uncharged when
- A page is removed from radix-tree and not SwapCache.
- When SwapCache is removed, a charge is moved to swap_cgroup.
- When swp_entry's refcnt goes down to 0, a charge in swap_cgroup
disappears.
7. Page Migration
One of the most complicated functions is page-migration-handler.
Memcg has 2 routines. Assume that we are migrating a page's contents
from OLDPAGE to NEWPAGE.
Usual migration logic is..
(a) remove the page from LRU.
(b) allocate NEWPAGE (migration target)
(c) lock by lock_page().
(d) unmap all mappings.
(e-1) If necessary, replace entry in radix-tree.
(e-2) move contents of a page.
(f) map all mappings again.
(g) pushback the page to LRU.
(-) OLDPAGE will be freed.
Before (g), memcg should complete all necessary charge/uncharge to
NEWPAGE/OLDPAGE.
The point is....
- If OLDPAGE is anonymous, all charges will be dropped at (d) because
try_to_unmap() drops all mapcount and the page will not be
SwapCache.
- If OLDPAGE is SwapCache, charges will be kept at (g) because
__delete_from_swap_cache() isn't called at (e-1)
- If OLDPAGE is page-cache, charges will be kept at (g) because
remove_from_swap_cache() isn't called at (e-1)
memcg provides following hooks.
- mem_cgroup_prepare_migration(OLDPAGE)
Called after (b) to account a charge (usage += PAGE_SIZE) against
memcg which OLDPAGE belongs to.
- mem_cgroup_end_migration(OLDPAGE, NEWPAGE)
Called after (f) before (g).
If OLDPAGE is used, commit OLDPAGE again. If OLDPAGE is already
charged, a charge by prepare_migration() is automatically canceled.
If NEWPAGE is used, commit NEWPAGE and uncharge OLDPAGE.
But zap_pte() (by exit or munmap) can be called while migration,
we have to check if OLDPAGE/NEWPAGE is a valid page after commit().
8. LRU
Each memcg has its own private LRU. Now, it's handling is under global
VM's control (means that it's handled under global zone->lru_lock).
Almost all routines around memcg's LRU is called by global LRU's
list management functions under zone->lru_lock().
A special function is mem_cgroup_isolate_pages(). This scans
memcg's private LRU and call __isolate_lru_page() to extract a page
from LRU.
(By __isolate_lru_page(), the page is removed from both of global and
private LRU.)
9. Typical Tests.
Tests for racy cases.
9.1 Small limit to memcg.
When you do test to do racy case, it's good test to set memcg's limit
to be very small rather than GB. Many races found in the test under
xKB or xxMB limits.
(Memory behavior under GB and Memory behavior under MB shows very
different situation.)
9.2 Shmem
Historically, memcg's shmem handling was poor and we saw some amount
of troubles here. This is because shmem is page-cache but can be
SwapCache. Test with shmem/tmpfs is always good test.
9.3 Migration
For NUMA, migration is an another special case. To do easy test, cpuset
is useful. Following is a sample script to do migration.
mount -t cgroup -o cpuset none /opt/cpuset
mkdir /opt/cpuset/01
echo 1 > /opt/cpuset/01/cpuset.cpus
echo 0 > /opt/cpuset/01/cpuset.mems
echo 1 > /opt/cpuset/01/cpuset.memory_migrate
mkdir /opt/cpuset/02
echo 1 > /opt/cpuset/02/cpuset.cpus
echo 1 > /opt/cpuset/02/cpuset.mems
echo 1 > /opt/cpuset/02/cpuset.memory_migrate
In above set, when you moves a task from 01 to 02, page migration to
node 0 to node 1 will occur. Following is a script to migrate all
under cpuset.
--
move_task()
{
for pid in $1
do
/bin/echo $pid >$2/tasks 2>/dev/null
echo -n $pid
echo -n " "
done
echo END
}
G1_TASK=`cat ${G1}/tasks`
G2_TASK=`cat ${G2}/tasks`
move_task "${G1_TASK}" ${G2} &
--
9.4 Memory hotplug.
memory hotplug test is one of good test.
to offline memory, do following.
# echo offline > /sys/devices/system/memory/memoryXXX/state
(XXX is the place of memory)
This is an easy way to test page migration, too.
9.5 mkdir/rmdir
When using hierarchy, mkdir/rmdir test should be done.
Use tests like the following.
echo 1 >/opt/cgroup/01/memory/use_hierarchy
mkdir /opt/cgroup/01/child_a
mkdir /opt/cgroup/01/child_b
set limit to 01.
add limit to 01/child_b
run jobs under child_a and child_b
create/delete following groups at random while jobs are running.
/opt/cgroup/01/child_a/child_aa
/opt/cgroup/01/child_b/child_bb
/opt/cgroup/01/child_c
running new jobs in new group is also good.
9.6 Mount with other subsystems.
Mounting with other subsystems is a good test because there is a
race and lock dependency with other cgroup subsystems.
example)
# mount -t cgroup none /cgroup -t cpuset,memory,cpu,devices
and do task move, mkdir, rmdir etc...under this.

135
Documentation/controllers/memory.txt → Documentation/cgroups/memory.txt
View File

@ -137,7 +137,32 @@ behind this approach is that a cgroup that aggressively uses a shared
page will eventually get charged for it (once it is uncharged from
the cgroup that brought it in -- this will happen on memory pressure).
2.4 Reclaim
Exception: If CONFIG_CGROUP_CGROUP_MEM_RES_CTLR_SWAP is not used..
When you do swapoff and make swapped-out pages of shmem(tmpfs) to
be backed into memory in force, charges for pages are accounted against the
caller of swapoff rather than the users of shmem.
2.4 Swap Extension (CONFIG_CGROUP_MEM_RES_CTLR_SWAP)
Swap Extension allows you to record charge for swap. A swapped-in page is
charged back to original page allocator if possible.
When swap is accounted, following files are added.
- memory.memsw.usage_in_bytes.
- memory.memsw.limit_in_bytes.
usage of mem+swap is limited by memsw.limit_in_bytes.
Note: why 'mem+swap' rather than swap.
The global LRU(kswapd) can swap out arbitrary pages. Swap-out means
to move account from memory to swap...there is no change in usage of
mem+swap.
In other words, when we want to limit the usage of swap without affecting
global LRU, mem+swap limit is better than just limiting swap from OS point
of view.
2.5 Reclaim
Each cgroup maintains a per cgroup LRU that consists of an active
and inactive list. When a cgroup goes over its limit, we first try
@ -207,12 +232,6 @@ exceeded.
The memory.stat file gives accounting information. Now, the number of
caches, RSS and Active pages/Inactive pages are shown.
The memory.force_empty gives an interface to drop *all* charges by force.
# echo 1 > memory.force_empty
will drop all charges in cgroup. Currently, this is maintained for test.
4. Testing
Balbir posted lmbench, AIM9, LTP and vmmstress results [10] and [11].
@ -242,10 +261,106 @@ reclaimed.
A cgroup can be removed by rmdir, but as discussed in sections 4.1 and 4.2, a
cgroup might have some charge associated with it, even though all
tasks have migrated away from it. Such charges are automatically dropped at
rmdir() if there are no tasks.
tasks have migrated away from it.
Such charges are freed(at default) or moved to its parent. When moved,
both of RSS and CACHES are moved to parent.
If both of them are busy, rmdir() returns -EBUSY. See 5.1 Also.
5. TODO
Charges recorded in swap information is not updated at removal of cgroup.
Recorded information is discarded and a cgroup which uses swap (swapcache)
will be charged as a new owner of it.
5. Misc. interfaces.
5.1 force_empty
memory.force_empty interface is provided to make cgroup's memory usage empty.
You can use this interface only when the cgroup has no tasks.
When writing anything to this
# echo 0 > memory.force_empty
Almost all pages tracked by this memcg will be unmapped and freed. Some of
pages cannot be freed because it's locked or in-use. Such pages are moved
to parent and this cgroup will be empty. But this may return -EBUSY in
some too busy case.
Typical use case of this interface is that calling this before rmdir().
Because rmdir() moves all pages to parent, some out-of-use page caches can be
moved to the parent. If you want to avoid that, force_empty will be useful.
5.2 stat file
memory.stat file includes following statistics (now)
cache - # of pages from page-cache and shmem.
rss - # of pages from anonymous memory.
pgpgin - # of event of charging
pgpgout - # of event of uncharging
active_anon - # of pages on active lru of anon, shmem.
inactive_anon - # of pages on active lru of anon, shmem
active_file - # of pages on active lru of file-cache
inactive_file - # of pages on inactive lru of file cache
unevictable - # of pages cannot be reclaimed.(mlocked etc)
Below is depend on CONFIG_DEBUG_VM.
inactive_ratio - VM inernal parameter. (see mm/page_alloc.c)
recent_rotated_anon - VM internal parameter. (see mm/vmscan.c)
recent_rotated_file - VM internal parameter. (see mm/vmscan.c)
recent_scanned_anon - VM internal parameter. (see mm/vmscan.c)
recent_scanned_file - VM internal parameter. (see mm/vmscan.c)
Memo:
recent_rotated means recent frequency of lru rotation.
recent_scanned means recent # of scans to lru.
showing for better debug please see the code for meanings.
5.3 swappiness
Similar to /proc/sys/vm/swappiness, but affecting a hierarchy of groups only.
Following cgroup's swapiness can't be changed.
- root cgroup (uses /proc/sys/vm/swappiness).
- a cgroup which uses hierarchy and it has child cgroup.
- a cgroup which uses hierarchy and not the root of hierarchy.
6. Hierarchy support
The memory controller supports a deep hierarchy and hierarchical accounting.
The hierarchy is created by creating the appropriate cgroups in the
cgroup filesystem. Consider for example, the following cgroup filesystem
hierarchy
root
/ | \
/ | \
a b c
| \
| \
d e
In the diagram above, with hierarchical accounting enabled, all memory
usage of e, is accounted to its ancestors up until the root (i.e, c and root),
that has memory.use_hierarchy enabled. If one of the ancestors goes over its
limit, the reclaim algorithm reclaims from the tasks in the ancestor and the
children of the ancestor.
6.1 Enabling hierarchical accounting and reclaim
The memory controller by default disables the hierarchy feature. Support
can be enabled by writing 1 to memory.use_hierarchy file of the root cgroup
# echo 1 > memory.use_hierarchy
The feature can be disabled by
# echo 0 > memory.use_hierarchy
NOTE1: Enabling/disabling will fail if the cgroup already has other
cgroups created below it.
NOTE2: This feature can be enabled/disabled per subtree.
7. TODO
1. Add support for accounting huge pages (as a separate controller)
2. Make per-cgroup scanner reclaim not-shared pages first

0
Documentation/controllers/resource_counter.txt → Documentation/cgroups/resource_counter.txt
View File

6
Documentation/cpu-freq/user-guide.txt
View File

@ -93,10 +93,8 @@ Several "PowerBook" and "iBook2" notebooks are supported.
1.5 SuperH
----------
The following SuperH processors are supported by cpufreq:
SH-3
SH-4
All SuperH processors supporting rate rounding through the clock
framework are supported by cpufreq.
1.6 Blackfin
------------

17
Documentation/cpu-hotplug.txt
View File

@ -50,16 +50,17 @@ additional_cpus=n (*) Use this to limit hotpluggable cpus. This option sets
cpu_possible_map = cpu_present_map + additional_cpus
(*) Option valid only for following architectures
- x86_64, ia64
- ia64
ia64 and x86_64 use the number of disabled local apics in ACPI tables MADT
to determine the number of potentially hot-pluggable cpus. The implementation
should only rely on this to count the # of cpus, but *MUST* not rely on the
apicid values in those tables for disabled apics. In the event BIOS doesn't
mark such hot-pluggable cpus as disabled entries, one could use this
parameter "additional_cpus=x" to represent those cpus in the cpu_possible_map.
ia64 uses the number of disabled local apics in ACPI tables MADT to
determine the number of potentially hot-pluggable cpus. The implementation
should only rely on this to count the # of cpus, but *MUST* not rely
on the apicid values in those tables for disabled apics. In the event
BIOS doesn't mark such hot-pluggable cpus as disabled entries, one could
use this parameter "additional_cpus=x" to represent those cpus in the
cpu_possible_map.
possible_cpus=n [s390 only] use this to set hotpluggable cpus.
possible_cpus=n [s390,x86_64] use this to set hotpluggable cpus.
This option sets possible_cpus bits in
cpu_possible_map. Thus keeping the numbers of bits set
constant even if the machine gets rebooted.

48
Documentation/cputopology.txt
View File

@ -31,3 +31,51 @@ not defined by include/asm-XXX/topology.h:
2) core_id: 0
3) thread_siblings: just the given CPU
4) core_siblings: just the given CPU
Additionally, cpu topology information is provided under
/sys/devices/system/cpu and includes these files. The internal
source for the output is in brackets ("[]").
kernel_max: the maximum cpu index allowed by the kernel configuration.
[NR_CPUS-1]
offline: cpus that are not online because they have been
HOTPLUGGED off (see cpu-hotplug.txt) or exceed the limit
of cpus allowed by the kernel configuration (kernel_max
above). [~cpu_online_mask + cpus >= NR_CPUS]
online: cpus that are online and being scheduled [cpu_online_mask]
possible: cpus that have been allocated resources and can be
brought online if they are present. [cpu_possible_mask]
present: cpus that have been identified as being present in the
system. [cpu_present_mask]
The format for the above output is compatible with cpulist_parse()
[see <linux/cpumask.h>]. Some examples follow.
In this example, there are 64 cpus in the system but cpus 32-63 exceed
the kernel max which is limited to 0..31 by the NR_CPUS config option
being 32. Note also that cpus 2 and 4-31 are not online but could be
brought online as they are both present and possible.
kernel_max: 31
offline: 2,4-31,32-63
online: 0-1,3
possible: 0-31
present: 0-31
In this example, the NR_CPUS config option is 128, but the kernel was
started with possible_cpus=144. There are 4 cpus in the system and cpu2
was manually taken offline (and is the only cpu that can be brought
online.)
kernel_max: 127
offline: 2,4-127,128-143
online: 0-1,3
possible: 0-127
present: 0-3
See cpu-hotplug.txt for the possible_cpus=NUM kernel start parameter
as well as more information on the various cpumask's.

582
Documentation/credentials.txt Normal file
View File

@ -0,0 +1,582 @@
====================
CREDENTIALS IN LINUX
====================
By: David Howells <dhowells@redhat.com>
Contents:
(*) Overview.
(*) Types of credentials.
(*) File markings.
(*) Task credentials.
- Immutable credentials.
- Accessing task credentials.
- Accessing another task's credentials.
- Altering credentials.
- Managing credentials.
(*) Open file credentials.
(*) Overriding the VFS's use of credentials.
========
OVERVIEW
========
There are several parts to the security check performed by Linux when one
object acts upon another:
(1) Objects.
Objects are things in the system that may be acted upon directly by
userspace programs. Linux has a variety of actionable objects, including:
- Tasks
- Files/inodes
- Sockets
- Message queues
- Shared memory segments
- Semaphores
- Keys
As a part of the description of all these objects there is a set of
credentials. What's in the set depends on the type of object.
(2) Object ownership.
Amongst the credentials of most objects, there will be a subset that
indicates the ownership of that object. This is used for resource
accounting and limitation (disk quotas and task rlimits for example).
In a standard UNIX filesystem, for instance, this will be defined by the
UID marked on the inode.
(3) The objective context.
Also amongst the credentials of those objects, there will be a subset that
indicates the 'objective context' of that object. This may or may not be
the same set as in (2) - in standard UNIX files, for instance, this is the
defined by the UID and the GID marked on the inode.
The objective context is used as part of the security calculation that is
carried out when an object is acted upon.
(4) Subjects.
A subject is an object that is acting upon another object.
Most of the objects in the system are inactive: they don't act on other
objects within the system. Processes/tasks are the obvious exception:
they do stuff; they access and manipulate things.
Objects other than tasks may under some circumstances also be subjects.
For instance an open file may send SIGIO to a task using the UID and EUID
given to it by a task that called fcntl(F_SETOWN) upon it. In this case,
the file struct will have a subjective context too.
(5) The subjective context.
A subject has an additional interpretation of its credentials. A subset
of its credentials forms the 'subjective context'. The subjective context
is used as part of the security calculation that is carried out when a
subject acts.
A Linux task, for example, has the FSUID, FSGID and the supplementary
group list for when it is acting upon a file - which are quite separate
from the real UID and GID that normally form the objective context of the
task.
(6) Actions.
Linux has a number of actions available that a subject may perform upon an
object. The set of actions available depends on the nature of the subject
and the object.
Actions include reading, writing, creating and deleting files; forking or
signalling and tracing tasks.
(7) Rules, access control lists and security calculations.
When a subject acts upon an object, a security calculation is made. This
involves taking the subjective context, the objective context and the
action, and searching one or more sets of rules to see whether the subject
is granted or denied permission to act in the desired manner on the
object, given those contexts.
There are two main sources of rules:
(a) Discretionary access control (DAC):
Sometimes the object will include sets of rules as part of its
description. This is an 'Access Control List' or 'ACL'. A Linux
file may supply more than one ACL.
A traditional UNIX file, for example, includes a permissions mask that
is an abbreviated ACL with three fixed classes of subject ('user',
'group' and 'other'), each of which may be granted certain privileges
('read', 'write' and 'execute' - whatever those map to for the object
in question). UNIX file permissions do not allow the arbitrary
specification of subjects, however, and so are of limited use.
A Linux file might also sport a POSIX ACL. This is a list of rules
that grants various permissions to arbitrary subjects.
(b) Mandatory access control (MAC):
The system as a whole may have one or more sets of rules that get
applied to all subjects and objects, regardless of their source.
SELinux and Smack are examples of this.
In the case of SELinux and Smack, each object is given a label as part
of its credentials. When an action is requested, they take the
subject label, the object label and the action and look for a rule
that says that this action is either granted or denied.
====================
TYPES OF CREDENTIALS
====================
The Linux kernel supports the following types of credentials:
(1) Traditional UNIX credentials.
Real User ID
Real Group ID
The UID and GID are carried by most, if not all, Linux objects, even if in
some cases it has to be invented (FAT or CIFS files for example, which are
derived from Windows). These (mostly) define the objective context of
that object, with tasks being slightly different in some cases.
Effective, Saved and FS User ID
Effective, Saved and FS Group ID
Supplementary groups
These are additional credentials used by tasks only. Usually, an
EUID/EGID/GROUPS will be used as the subjective context, and real UID/GID
will be used as the objective. For tasks, it should be noted that this is
not always true.
(2) Capabilities.
Set of permitted capabilities
Set of inheritable capabilities
Set of effective capabilities
Capability bounding set
These are only carried by tasks. They indicate superior capabilities
granted piecemeal to a task that an ordinary task wouldn't otherwise have.
These are manipulated implicitly by changes to the traditional UNIX
credentials, but can also be manipulated directly by the capset() system
call.
The permitted capabilities are those caps that the process might grant
itself to its effective or permitted sets through capset(). This
inheritable set might also be so constrained.
The effective capabilities are the ones that a task is actually allowed to
make use of itself.
The inheritable capabilities are the ones that may get passed across
execve().
The bounding set limits the capabilities that may be inherited across
execve(), especially when a binary is executed that will execute as UID 0.
(3) Secure management flags (securebits).
These are only carried by tasks. These govern the way the above
credentials are manipulated and inherited over certain operations such as
execve(). They aren't used directly as objective or subjective
credentials.
(4) Keys and keyrings.
These are only carried by tasks. They carry and cache security tokens
that don't fit into the other standard UNIX credentials. They are for
making such things as network filesystem keys available to the file
accesses performed by processes, without the necessity of ordinary
programs having to know about security details involved.
Keyrings are a special type of key. They carry sets of other keys and can
be searched for the desired key. Each process may subscribe to a number
of keyrings:
Per-thread keying
Per-process keyring
Per-session keyring
When a process accesses a key, if not already present, it will normally be
cached on one of these keyrings for future accesses to find.
For more information on using keys, see Documentation/keys.txt.
(5) LSM
The Linux Security Module allows extra controls to be placed over the
operations that a task may do. Currently Linux supports two main
alternate LSM options: SELinux and Smack.
Both work by labelling the objects in a system and then applying sets of
rules (policies) that say what operations a task with one label may do to
an object with another label.
(6) AF_KEY
This is a socket-based approach to credential management for networking
stacks [RFC 2367]. It isn't discussed by this document as it doesn't
interact directly with task and file credentials; rather it keeps system
level credentials.
When a file is opened, part of the opening task's subjective context is
recorded in the file struct created. This allows operations using that file
struct to use those credentials instead of the subjective context of the task
that issued the operation. An example of this would be a file opened on a
network filesystem where the credentials of the opened file should be presented
to the server, regardless of who is actually doing a read or a write upon it.
=============
FILE MARKINGS
=============
Files on disk or obtained over the network may have annotations that form the
objective security context of that file. Depending on the type of filesystem,
this may include one or more of the following:
(*) UNIX UID, GID, mode;
(*) Windows user ID;
(*) Access control list;
(*) LSM security label;
(*) UNIX exec privilege escalation bits (SUID/SGID);
(*) File capabilities exec privilege escalation bits.
These are compared to the task's subjective security context, and certain
operations allowed or disallowed as a result. In the case of execve(), the
privilege escalation bits come into play, and may allow the resulting process
extra privileges, based on the annotations on the executable file.
================
TASK CREDENTIALS
================
In Linux, all of a task's credentials are held in (uid, gid) or through
(groups, keys, LSM security) a refcounted structure of type 'struct cred'.
Each task points to its credentials by a pointer called 'cred' in its
task_struct.
Once a set of credentials has been prepared and committed, it may not be
changed, barring the following exceptions:
(1) its reference count may be changed;
(2) the reference count on the group_info struct it points to may be changed;
(3) the reference count on the security data it points to may be changed;
(4) the reference count on any keyrings it points to may be changed;
(5) any keyrings it points to may be revoked, expired or have their security
attributes changed; and
(6) the contents of any keyrings to which it points may be changed (the whole
point of keyrings being a shared set of credentials, modifiable by anyone
with appropriate access).
To alter anything in the cred struct, the copy-and-replace principle must be
adhered to. First take a copy, then alter the copy and then use RCU to change
the task pointer to make it point to the new copy. There are wrappers to aid
with this (see below).
A task may only alter its _own_ credentials; it is no longer permitted for a
task to alter another's credentials. This means the capset() system call is no
longer permitted to take any PID other than the one of the current process.
Also keyctl_instantiate() and keyctl_negate() functions no longer permit
attachment to process-specific keyrings in the requesting process as the
instantiating process may need to create them.
IMMUTABLE CREDENTIALS
---------------------
Once a set of credentials has been made public (by calling commit_creds() for
example), it must be considered immutable, barring two exceptions:
(1) The reference count may be altered.
(2) Whilst the keyring subscriptions of a set of credentials may not be
changed, the keyrings subscribed to may have their contents altered.
To catch accidental credential alteration at compile time, struct task_struct
has _const_ pointers to its credential sets, as does struct file. Furthermore,
certain functions such as get_cred() and put_cred() operate on const pointers,
thus rendering casts unnecessary, but require to temporarily ditch the const
qualification to be able to alter the reference count.
ACCESSING TASK CREDENTIALS
--------------------------
A task being able to alter only its own credentials permits the current process
to read or replace its own credentials without the need for any form of locking
- which simplifies things greatly. It can just call:
const struct cred *current_cred()
to get a pointer to its credentials structure, and it doesn't have to release
it afterwards.
There are convenience wrappers for retrieving specific aspects of a task's
credentials (the value is simply returned in each case):
uid_t current_uid(void) Current's real UID
gid_t current_gid(void) Current's real GID
uid_t current_euid(void) Current's effective UID
gid_t current_egid(void) Current's effective GID
uid_t current_fsuid(void) Current's file access UID
gid_t current_fsgid(void) Current's file access GID
kernel_cap_t current_cap(void) Current's effective capabilities
void *current_security(void) Current's LSM security pointer
struct user_struct *current_user(void) Current's user account
There are also convenience wrappers for retrieving specific associated pairs of
a task's credentials:
void current_uid_gid(uid_t *, gid_t *);
void current_euid_egid(uid_t *, gid_t *);
void current_fsuid_fsgid(uid_t *, gid_t *);
which return these pairs of values through their arguments after retrieving
them from the current task's credentials.
In addition, there is a function for obtaining a reference on the current
process's current set of credentials:
const struct cred *get_current_cred(void);
and functions for getting references to one of the credentials that don't
actually live in struct cred:
struct user_struct *get_current_user(void);
struct group_info *get_current_groups(void);
which get references to the current process's user accounting structure and
supplementary groups list respectively.
Once a reference has been obtained, it must be released with put_cred(),
free_uid() or put_group_info() as appropriate.
ACCESSING ANOTHER TASK'S CREDENTIALS
------------------------------------
Whilst a task may access its own credentials without the need for locking, the
same is not true of a task wanting to access another task's credentials. It
must use the RCU read lock and rcu_dereference().
The rcu_dereference() is wrapped by:
const struct cred *__task_cred(struct task_struct *task);
This should be used inside the RCU read lock, as in the following example:
void foo(struct task_struct *t, struct foo_data *f)
{
const struct cred *tcred;
...
rcu_read_lock();
tcred = __task_cred(t);
f->uid = tcred->uid;
f->gid = tcred->gid;
f->groups = get_group_info(tcred->groups);
rcu_read_unlock();
...
}
A function need not get RCU read lock to use __task_cred() if it is holding a
spinlock at the time as this implicitly holds the RCU read lock.
Should it be necessary to hold another task's credentials for a long period of
time, and possibly to sleep whilst doing so, then the caller should get a
reference on them using:
const struct cred *get_task_cred(struct task_struct *task);
This does all the RCU magic inside of it. The caller must call put_cred() on
the credentials so obtained when they're finished with.
There are a couple of convenience functions to access bits of another task's
credentials, hiding the RCU magic from the caller:
uid_t task_uid(task) Task's real UID
uid_t task_euid(task) Task's effective UID
If the caller is holding a spinlock or the RCU read lock at the time anyway,
then:
__task_cred(task)->uid
__task_cred(task)->euid
should be used instead. Similarly, if multiple aspects of a task's credentials
need to be accessed, RCU read lock or a spinlock should be used, __task_cred()
called, the result stored in a temporary pointer and then the credential
aspects called from that before dropping the lock. This prevents the
potentially expensive RCU magic from being invoked multiple times.
Should some other single aspect of another task's credentials need to be
accessed, then this can be used:
task_cred_xxx(task, member)
where 'member' is a non-pointer member of the cred struct. For instance:
uid_t task_cred_xxx(task, suid);
will retrieve 'struct cred::suid' from the task, doing the appropriate RCU
magic. This may not be used for pointer members as what they point to may
disappear the moment the RCU read lock is dropped.
ALTERING CREDENTIALS
--------------------
As previously mentioned, a task may only alter its own credentials, and may not
alter those of another task. This means that it doesn't need to use any
locking to alter its own credentials.
To alter the current process's credentials, a function should first prepare a
new set of credentials by calling:
struct cred *prepare_creds(void);
this locks current->cred_replace_mutex and then allocates and constructs a
duplicate of the current process's credentials, returning with the mutex still
held if successful. It returns NULL if not successful (out of memory).
The mutex prevents ptrace() from altering the ptrace state of a process whilst
security checks on credentials construction and changing is taking place as
the ptrace state may alter the outcome, particularly in the case of execve().
The new credentials set should be altered appropriately, and any security
checks and hooks done. Both the current and the proposed sets of credentials
are available for this purpose as current_cred() will return the current set
still at this point.
When the credential set is ready, it should be committed to the current process
by calling:
int commit_creds(struct cred *new);
This will alter various aspects of the credentials and the process, giving the
LSM a chance to do likewise, then it will use rcu_assign_pointer() to actually
commit the new credentials to current->cred, it will release
current->cred_replace_mutex to allow ptrace() to take place, and it will notify
the scheduler and others of the changes.
This function is guaranteed to return 0, so that it can be tail-called at the
end of such functions as sys_setresuid().
Note that this function consumes the caller's reference to the new credentials.
The caller should _not_ call put_cred() on the new credentials afterwards.
Furthermore, once this function has been called on a new set of credentials,
those credentials may _not_ be changed further.
Should the security checks fail or some other error occur after prepare_creds()
has been called, then the following function should be invoked:
void abort_creds(struct cred *new);
This releases the lock on current->cred_replace_mutex that prepare_creds() got
and then releases the new credentials.
A typical credentials alteration function would look something like this:
int alter_suid(uid_t suid)
{
struct cred *new;
int ret;
new = prepare_creds();
if (!new)
return -ENOMEM;
new->suid = suid;
ret = security_alter_suid(new);
if (ret < 0) {
abort_creds(new);
return ret;
}
return commit_creds(new);
}
MANAGING CREDENTIALS
--------------------
There are some functions to help manage credentials:
(*) void put_cred(const struct cred *cred);
This releases a reference to the given set of credentials. If the
reference count reaches zero, the credentials will be scheduled for
destruction by the RCU system.
(*) const struct cred *get_cred(const struct cred *cred);
This gets a reference on a live set of credentials, returning a pointer to
that set of credentials.
(*) struct cred *get_new_cred(struct cred *cred);
This gets a reference on a set of credentials that is under construction
and is thus still mutable, returning a pointer to that set of credentials.
=====================
OPEN FILE CREDENTIALS
=====================
When a new file is opened, a reference is obtained on the opening task's
credentials and this is attached to the file struct as 'f_cred' in place of
'f_uid' and 'f_gid'. Code that used to access file->f_uid and file->f_gid
should now access file->f_cred->fsuid and file->f_cred->fsgid.
It is safe to access f_cred without the use of RCU or locking because the
pointer will not change over the lifetime of the file struct, and nor will the
contents of the cred struct pointed to, barring the exceptions listed above
(see the Task Credentials section).
=======================================
OVERRIDING THE VFS'S USE OF CREDENTIALS
=======================================
Under some circumstances it is desirable to override the credentials used by
the VFS, and that can be done by calling into such as vfs_mkdir() with a
different set of credentials. This is done in the following places:
(*) sys_faccessat().
(*) do_coredump().
(*) nfs4recover.c.

86
Documentation/crypto/async-tx-api.txt
View File

@ -13,9 +13,9 @@
3.6 Constraints
3.7 Example
4 DRIVER DEVELOPER NOTES
4 DMAENGINE DRIVER DEVELOPER NOTES
4.1 Conformance points
4.2 "My application needs finer control of hardware channels"
4.2 "My application needs exclusive control of hardware channels"
5 SOURCE
@ -150,6 +150,7 @@ ops_run_* and ops_complete_* routines in drivers/md/raid5.c for more
implementation examples.
4 DRIVER DEVELOPMENT NOTES
4.1 Conformance points:
There are a few conformance points required in dmaengine drivers to
accommodate assumptions made by applications using the async_tx API:
@ -158,58 +159,49 @@ accommodate assumptions made by applications using the async_tx API:
3/ Use async_tx_run_dependencies() in the descriptor clean up path to
handle submission of dependent operations
4.2 "My application needs finer control of hardware channels"
This requirement seems to arise from cases where a DMA engine driver is
trying to support device-to-memory DMA. The dmaengine and async_tx
implementations were designed for offloading memory-to-memory
operations; however, there are some capabilities of the dmaengine layer
that can be used for platform-specific channel management.
Platform-specific constraints can be handled by registering the
application as a 'dma_client' and implementing a 'dma_event_callback' to
apply a filter to the available channels in the system. Before showing
how to implement a custom dma_event callback some background of
dmaengine's client support is required.
4.2 "My application needs exclusive control of hardware channels"
Primarily this requirement arises from cases where a DMA engine driver
is being used to support device-to-memory operations. A channel that is
performing these operations cannot, for many platform specific reasons,
be shared. For these cases the dma_request_channel() interface is
provided.
The following routines in dmaengine support multiple clients requesting
use of a channel:
- dma_async_client_register(struct dma_client *client)
- dma_async_client_chan_request(struct dma_client *client)
The interface is:
struct dma_chan *dma_request_channel(dma_cap_mask_t mask,
dma_filter_fn filter_fn,
void *filter_param);
dma_async_client_register takes a pointer to an initialized dma_client
structure. It expects that the 'event_callback' and 'cap_mask' fields
are already initialized.
Where dma_filter_fn is defined as:
typedef bool (*dma_filter_fn)(struct dma_chan *chan, void *filter_param);
dma_async_client_chan_request triggers dmaengine to notify the client of
all channels that satisfy the capability mask. It is up to the client's
event_callback routine to track how many channels the client needs and
how many it is currently using. The dma_event_callback routine returns a
dma_state_client code to let dmaengine know the status of the
allocation.
When the optional 'filter_fn' parameter is set to NULL
dma_request_channel simply returns the first channel that satisfies the
capability mask. Otherwise, when the mask parameter is insufficient for
specifying the necessary channel, the filter_fn routine can be used to
disposition the available channels in the system. The filter_fn routine
is called once for each free channel in the system. Upon seeing a
suitable channel filter_fn returns DMA_ACK which flags that channel to
be the return value from dma_request_channel. A channel allocated via
this interface is exclusive to the caller, until dma_release_channel()
is called.
Below is the example of how to extend this functionality for
platform-specific filtering of the available channels beyond the
standard capability mask:
The DMA_PRIVATE capability flag is used to tag dma devices that should
not be used by the general-purpose allocator. It can be set at
initialization time if it is known that a channel will always be
private. Alternatively, it is set when dma_request_channel() finds an
unused "public" channel.
static enum dma_state_client
my_dma_client_callback(struct dma_client *client,
struct dma_chan *chan, enum dma_state state)
{
struct dma_device *dma_dev;
struct my_platform_specific_dma *plat_dma_dev;
dma_dev = chan->device;
plat_dma_dev = container_of(dma_dev,
struct my_platform_specific_dma,
dma_dev);
if (!plat_dma_dev->platform_specific_capability)
return DMA_DUP;
. . .
}
A couple caveats to note when implementing a driver and consumer:
1/ Once a channel has been privately allocated it will no longer be
considered by the general-purpose allocator even after a call to
dma_release_channel().
2/ Since capabilities are specified at the device level a dma_device
with multiple channels will either have all channels public, or all
channels private.
5 SOURCE
include/linux/dmaengine.h: core header file for DMA drivers and clients
include/linux/dmaengine.h: core header file for DMA drivers and api users
drivers/dma/dmaengine.c: offload engine channel management routines
drivers/dma/: location for offload engine drivers
include/linux/async_tx.h: core header file for the async_tx api

4
Documentation/dell_rbu.txt
View File

@ -81,8 +81,8 @@ Until this step is completed the driver cannot be unloaded.
Also echoing either mono ,packet or init in to image_type will free up the
memory allocated by the driver.
If an user by accident executes steps 1 and 3 above without executing step 2;
it will make the /sys/class/firmware/dell_rbu/ entries to disappear.
If a user by accident executes steps 1 and 3 above without executing step 2;
it will make the /sys/class/firmware/dell_rbu/ entries disappear.
The entries can be recreated by doing the following
echo init > /sys/devices/platform/dell_rbu/image_type
NOTE: echoing init in image_type does not change it original value.

6
Documentation/development-process/4.Coding
View File

@ -375,10 +375,10 @@ say, this can be a large job, so it is best to be sure that the
justification is solid.
When making an incompatible API change, one should, whenever possible,
ensure that code which has not been updated is caught by the compiler.
ensure that code which has not been updated is caught by the compiler.
This will help you to be sure that you have found all in-tree uses of that
interface. It will also alert developers of out-of-tree code that there is
a change that they need to respond to. Supporting out-of-tree code is not
something that kernel developers need to be worried about, but we also do
not have to make life harder for out-of-tree developers than it it needs to
be.
not have to make life harder for out-of-tree developers than it needs to
be.

1
Documentation/dmaengine.txt Normal file
View File

@ -0,0 +1 @@
See Documentation/crypto/async-tx-api.txt

69
Documentation/dvb/technisat.txt Normal file
View File

@ -0,0 +1,69 @@
How to set up the Technisat devices
===================================
1) Find out what device you have
================================
First start your linux box with a shipped kernel:
lspci -vvv for a PCI device (lsusb -vvv for an USB device) will show you for example:
02:0b.0 Network controller: Techsan Electronics Co Ltd B2C2 FlexCopII DVB chip / Technisat SkyStar2 DVB card (rev 02)
dmesg | grep frontend may show you for example:
DVB: registering frontend 0 (Conexant CX24123/CX24109)...
2) Kernel compilation:
======================
If the Technisat is the only TV device in your box get rid of unnecessary modules and check this one:
"Multimedia devices" => "Customise analog and hybrid tuner modules to build"
In this directory uncheck every driver which is activated there.
Then please activate:
2a) Main module part:
a.)"Multimedia devices" => "DVB/ATSC adapters" => "Technisat/B2C2 FlexcopII(b) and FlexCopIII adapters"
b.)"Multimedia devices" => "DVB/ATSC adapters" => "Technisat/B2C2 FlexcopII(b) and FlexCopIII adapters" => "Technisat/B2C2 Air/Sky/Cable2PC PCI" in case of a PCI card OR
c.)"Multimedia devices" => "DVB/ATSC adapters" => "Technisat/B2C2 FlexcopII(b) and FlexCopIII adapters" => "Technisat/B2C2 Air/Sky/Cable2PC USB" in case of an USB 1.1 adapter
d.)"Multimedia devices" => "DVB/ATSC adapters" => "Technisat/B2C2 FlexcopII(b) and FlexCopIII adapters" => "Enable debug for the B2C2 FlexCop drivers"
Notice: d.) is helpful for troubleshooting
2b) Frontend module part:
1.) Revision 2.3:
a.)"Multimedia devices" => "Customise DVB frontends" => "Customise the frontend modules to build"
b.)"Multimedia devices" => "Customise DVB frontends" => "Zarlink VP310/MT312/ZL10313 based"
2.) Revision 2.6:
a.)"Multimedia devices" => "Customise DVB frontends" => "Customise the frontend modules to build"
b.)"Multimedia devices" => "Customise DVB frontends" => "ST STV0299 based"
3.) Revision 2.7:
a.)"Multimedia devices" => "Customise DVB frontends" => "Customise the frontend modules to build"
b.)"Multimedia devices" => "Customise DVB frontends" => "Samsung S5H1420 based"
c.)"Multimedia devices" => "Customise DVB frontends" => "Integrant ITD1000 Zero IF tuner for DVB-S/DSS"
d.)"Multimedia devices" => "Customise DVB frontends" => "ISL6421 SEC controller"
4.) Revision 2.8:
a.)"Multimedia devices" => "Customise DVB frontends" => "Customise the frontend modules to build"
b.)"Multimedia devices" => "Customise DVB frontends" => "Conexant CX24113/CX24128 tuner for DVB-S/DSS"
c.)"Multimedia devices" => "Customise DVB frontends" => "Conexant CX24123 based"
d.)"Multimedia devices" => "Customise DVB frontends" => "ISL6421 SEC controller"
5.) DVB-T card:
a.)"Multimedia devices" => "Customise DVB frontends" => "Customise the frontend modules to build"
b.)"Multimedia devices" => "Customise DVB frontends" => "Zarlink MT352 based"
6.) DVB-C card:
a.)"Multimedia devices" => "Customise DVB frontends" => "Customise the frontend modules to build"
b.)"Multimedia devices" => "Customise DVB frontends" => "ST STV0297 based"
7.) ATSC card 1st generation:
a.)"Multimedia devices" => "Customise DVB frontends" => "Customise the frontend modules to build"
b.)"Multimedia devices" => "Customise DVB frontends" => "Broadcom BCM3510"
8.) ATSC card 2nd generation:
a.)"Multimedia devices" => "Customise DVB frontends" => "Customise the frontend modules to build"
b.)"Multimedia devices" => "Customise DVB frontends" => "NxtWave Communications NXT2002/NXT2004 based"
c.)"Multimedia devices" => "Customise DVB frontends" => "LG Electronics LGDT3302/LGDT3303 based"
Author: Uwe Bugla <uwe.bugla@gmx.de> December 2008

92
Documentation/fb/pxafb.txt
View File

@ -5,9 +5,13 @@ The driver supports the following options, either via
options=<OPTIONS> when modular or video=pxafb:<OPTIONS> when built in.
For example:
modprobe pxafb options=mode:640x480-8,passive
modprobe pxafb options=vmem:2M,mode:640x480-8,passive
or on the kernel command line
video=pxafb:mode:640x480-8,passive
video=pxafb:vmem:2M,mode:640x480-8,passive
vmem: VIDEO_MEM_SIZE
Amount of video memory to allocate (can be suffixed with K or M
for kilobytes or megabytes)
mode:XRESxYRES[-BPP]
XRES == LCCR1_PPL + 1
@ -52,3 +56,87 @@ outputen:POLARITY
pixclockpol:POLARITY
pixel clock polarity
0 => falling edge, 1 => rising edge
Overlay Support for PXA27x and later LCD controllers
====================================================
PXA27x and later processors support overlay1 and overlay2 on-top of the
base framebuffer (although under-neath the base is also possible). They
support palette and no-palette RGB formats, as well as YUV formats (only
available on overlay2). These overlays have dedicated DMA channels and
behave in a similar way as a framebuffer.
However, there are some differences between these overlay framebuffers
and normal framebuffers, as listed below:
1. overlay can start at a 32-bit word aligned position within the base
framebuffer, which means they have a start (x, y). This information
is encoded into var->nonstd (no, var->xoffset and var->yoffset are
not for such purpose).
2. overlay framebuffer is allocated dynamically according to specified
'struct fb_var_screeninfo', the amount is decided by:
var->xres_virtual * var->yres_virtual * bpp
bpp = 16 -- for RGB565 or RGBT555
= 24 -- for YUV444 packed
= 24 -- for YUV444 planar
= 16 -- for YUV422 planar (1 pixel = 1 Y + 1/2 Cb + 1/2 Cr)
= 12 -- for YUV420 planar (1 pixel = 1 Y + 1/4 Cb + 1/4 Cr)
NOTE:
a. overlay does not support panning in x-direction, thus
var->xres_virtual will always be equal to var->xres
b. line length of overlay(s) must be on a 32-bit word boundary,
for YUV planar modes, it is a requirement for the component
with minimum bits per pixel, e.g. for YUV420, Cr component
for one pixel is actually 2-bits, it means the line length
should be a multiple of 16-pixels
c. starting horizontal position (XPOS) should start on a 32-bit
word boundary, otherwise the fb_check_var() will just fail.
d. the rectangle of the overlay should be within the base plane,
otherwise fail
Applications should follow the sequence below to operate an overlay
framebuffer:
a. open("/dev/fb[1-2]", ...)
b. ioctl(fd, FBIOGET_VSCREENINFO, ...)
c. modify 'var' with desired parameters:
1) var->xres and var->yres
2) larger var->yres_virtual if more memory is required,
usually for double-buffering
3) var->nonstd for starting (x, y) and color format
4) var->{red, green, blue, transp} if RGB mode is to be used
d. ioctl(fd, FBIOPUT_VSCREENINFO, ...)
e. ioctl(fd, FBIOGET_FSCREENINFO, ...)
f. mmap
g. ...
3. for YUV planar formats, these are actually not supported within the
framebuffer framework, application has to take care of the offsets
and lengths of each component within the framebuffer.
4. var->nonstd is used to pass starting (x, y) position and color format,
the detailed bit fields are shown below:
31 23 20 10 0
+-----------------+---+----------+----------+
| ... unused ... |FOR| XPOS | YPOS |
+-----------------+---+----------+----------+
FOR - color format, as defined by OVERLAY_FORMAT_* in pxafb.h
0 - RGB
1 - YUV444 PACKED
2 - YUV444 PLANAR
3 - YUV422 PLANAR
4 - YUR420 PLANAR
XPOS - starting horizontal position
YPOS - starting vertical position

48
Documentation/feature-removal-schedule.txt
View File

@ -120,13 +120,6 @@ Who: Christoph Hellwig <hch@lst.de>
---------------------------
What: eepro100 network driver
When: January 2007
Why: replaced by the e100 driver
Who: Adrian Bunk <bunk@stusta.de>
---------------------------
What: Unused EXPORT_SYMBOL/EXPORT_SYMBOL_GPL exports
(temporary transition config option provided until then)
The transition config option will also be removed at the same time.
@ -244,18 +237,6 @@ Who: Michael Buesch <mb@bu3sch.de>
---------------------------
What: init_mm export
When: 2.6.26
Why: Not used in-tree. The current out-of-tree users used it to
work around problems in the CPA code which should be resolved
by now. One usecase was described to provide verification code
of the CPA operation. That's a good idea in general, but such
code / infrastructure should be in the kernel and not in some
out-of-tree driver.
Who: Thomas Gleixner <tglx@linutronix.de>
----------------------------
What: usedac i386 kernel parameter
When: 2.6.27
Why: replaced by allowdac and no dac combination
@ -329,17 +310,28 @@ Who: Krzysztof Piotr Oledzki <ole@ans.pl>
---------------------------
What: ide-scsi (BLK_DEV_IDESCSI)
When: 2.6.29
Why: The 2.6 kernel supports direct writing to ide CD drives, which
eliminates the need for ide-scsi. The new method is more
efficient in every way.
Who: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
---------------------------
What: i2c_attach_client(), i2c_detach_client(), i2c_driver->detach_client()
When: 2.6.29 (ideally) or 2.6.30 (more likely)
Why: Deprecated by the new (standard) device driver binding model. Use
i2c_driver->probe() and ->remove() instead.
Who: Jean Delvare <khali@linux-fr.org>
---------------------------
What: fscher and fscpos drivers
When: June 2009
Why: Deprecated by the new fschmd driver.
Who: Hans de Goede <hdegoede@redhat.com>
Jean Delvare <khali@linux-fr.org>
---------------------------
What: SELinux "compat_net" functionality
When: 2.6.30 at the earliest
Why: In 2.6.18 the Secmark concept was introduced to replace the "compat_net"
network access control functionality of SELinux. Secmark offers both
better performance and greater flexibility than the "compat_net"
mechanism. Now that the major Linux distributions have moved to
Secmark, it is time to deprecate the older mechanism and start the
process of removing the old code.
Who: Paul Moore <paul.moore@hp.com>

12
Documentation/filesystems/Locking
View File

@ -97,8 +97,8 @@ prototypes:
void (*put_super) (struct super_block *);
void (*write_super) (struct super_block *);
int (*sync_fs)(struct super_block *sb, int wait);
void (*write_super_lockfs) (struct super_block *);
void (*unlockfs) (struct super_block *);
int (*freeze_fs) (struct super_block *);
int (*unfreeze_fs) (struct super_block *);
int (*statfs) (struct dentry *, struct kstatfs *);
int (*remount_fs) (struct super_block *, int *, char *);
void (*clear_inode) (struct inode *);
@ -119,8 +119,8 @@ delete_inode: no
put_super: yes yes no
write_super: no yes read
sync_fs: no no read
write_super_lockfs: ?
unlockfs: ?
freeze_fs: ?
unfreeze_fs: ?
statfs: no no no
remount_fs: yes yes maybe (see below)
clear_inode: no
@ -394,11 +394,10 @@ prototypes:
unsigned long (*get_unmapped_area)(struct file *, unsigned long,
unsigned long, unsigned long, unsigned long);
int (*check_flags)(int);
int (*dir_notify)(struct file *, unsigned long);
};
locking rules:
All except ->poll() may block.
All may block.
BKL
llseek: no (see below)
read: no
@ -424,7 +423,6 @@ sendfile: no
sendpage: no
get_unmapped_area: no
check_flags: no
dir_notify: no
->llseek() locking has moved from llseek to the individual llseek
implementations. If your fs is not using generic_file_llseek, you

91
Documentation/filesystems/btrfs.txt Normal file
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@ -0,0 +1,91 @@
BTRFS
=====
Btrfs is a new copy on write filesystem for Linux aimed at
implementing advanced features while focusing on fault tolerance,
repair and easy administration. Initially developed by Oracle, Btrfs
is licensed under the GPL and open for contribution from anyone.
Linux has a wealth of filesystems to choose from, but we are facing a
number of challenges with scaling to the large storage subsystems that
are becoming common in today's data centers. Filesystems need to scale
in their ability to address and manage large storage, and also in
their ability to detect, repair and tolerate errors in the data stored
on disk. Btrfs is under heavy development, and is not suitable for
any uses other than benchmarking and review. The Btrfs disk format is
not yet finalized.
The main Btrfs features include:
* Extent based file storage (2^64 max file size)
* Space efficient packing of small files
* Space efficient indexed directories
* Dynamic inode allocation
* Writable snapshots
* Subvolumes (separate internal filesystem roots)
* Object level mirroring and striping
* Checksums on data and metadata (multiple algorithms available)
* Compression
* Integrated multiple device support, with several raid algorithms
* Online filesystem check (not yet implemented)
* Very fast offline filesystem check
* Efficient incremental backup and FS mirroring (not yet implemented)
* Online filesystem defragmentation
MAILING LIST
============
There is a Btrfs mailing list hosted on vger.kernel.org. You can
find details on how to subscribe here:
http://vger.kernel.org/vger-lists.html#linux-btrfs
Mailing list archives are available from gmane:
http://dir.gmane.org/gmane.comp.file-systems.btrfs
IRC
===
Discussion of Btrfs also occurs on the #btrfs channel of the Freenode
IRC network.
UTILITIES
=========
Userspace tools for creating and manipulating Btrfs file systems are
available from the git repository at the following location:
http://git.kernel.org/?p=linux/kernel/git/mason/btrfs-progs-unstable.git
git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-progs-unstable.git
These include the following tools:
mkfs.btrfs: create a filesystem
btrfsctl: control program to create snapshots and subvolumes:
mount /dev/sda2 /mnt
btrfsctl -s new_subvol_name /mnt
btrfsctl -s snapshot_of_default /mnt/default
btrfsctl -s snapshot_of_new_subvol /mnt/new_subvol_name
btrfsctl -s snapshot_of_a_snapshot /mnt/snapshot_of_new_subvol
ls /mnt
default snapshot_of_a_snapshot snapshot_of_new_subvol
new_subvol_name snapshot_of_default
Snapshots and subvolumes cannot be deleted right now, but you can
rm -rf all the files and directories inside them.
btrfsck: do a limited check of the FS extent trees.
btrfs-debug-tree: print all of the FS metadata in text form. Example:
btrfs-debug-tree /dev/sda2 >& big_output_file

132
Documentation/filesystems/devpts.txt Normal file
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@ -0,0 +1,132 @@
To support containers, we now allow multiple instances of devpts filesystem,
such that indices of ptys allocated in one instance are independent of indices
allocated in other instances of devpts.
To preserve backward compatibility, this support for multiple instances is
enabled only if:
- CONFIG_DEVPTS_MULTIPLE_INSTANCES=y, and
- '-o newinstance' mount option is specified while mounting devpts
IOW, devpts now supports both single-instance and multi-instance semantics.
If CONFIG_DEVPTS_MULTIPLE_INSTANCES=n, there is no change in behavior and
this referred to as the "legacy" mode. In this mode, the new mount options
(-o newinstance and -o ptmxmode) will be ignored with a 'bogus option' message
on console.
If CONFIG_DEVPTS_MULTIPLE_INSTANCES=y and devpts is mounted without the
'newinstance' option (as in current start-up scripts) the new mount binds
to the initial kernel mount of devpts. This mode is referred to as the
'single-instance' mode and the current, single-instance semantics are
preserved, i.e PTYs are common across the system.
The only difference between this single-instance mode and the legacy mode
is the presence of new, '/dev/pts/ptmx' node with permissions 0000, which
can safely be ignored.
If CONFIG_DEVPTS_MULTIPLE_INSTANCES=y and 'newinstance' option is specified,
the mount is considered to be in the multi-instance mode and a new instance
of the devpts fs is created. Any ptys created in this instance are independent
of ptys in other instances of devpts. Like in the single-instance mode, the
/dev/pts/ptmx node is present. To effectively use the multi-instance mode,
open of /dev/ptmx must be a redirected to '/dev/pts/ptmx' using a symlink or
bind-mount.
Eg: A container startup script could do the following:
$ chmod 0666 /dev/pts/ptmx
$ rm /dev/ptmx
$ ln -s pts/ptmx /dev/ptmx
$ ns_exec -cm /bin/bash
# We are now in new container
$ umount /dev/pts
$ mount -t devpts -o newinstance lxcpts /dev/pts
$ sshd -p 1234
where 'ns_exec -cm /bin/bash' calls clone() with CLONE_NEWNS flag and execs
/bin/bash in the child process. A pty created by the sshd is not visible in
the original mount of /dev/pts.
User-space changes
------------------
In multi-instance mode (i.e '-o newinstance' mount option is specified at least
once), following user-space issues should be noted.
1. If -o newinstance mount option is never used, /dev/pts/ptmx can be ignored
and no change is needed to system-startup scripts.
2. To effectively use multi-instance mode (i.e -o newinstance is specified)
administrators or startup scripts should "redirect" open of /dev/ptmx to
/dev/pts/ptmx using either a bind mount or symlink.
$ mount -t devpts -o newinstance devpts /dev/pts
followed by either
$ rm /dev/ptmx
$ ln -s pts/ptmx /dev/ptmx
$ chmod 666 /dev/pts/ptmx
or
$ mount -o bind /dev/pts/ptmx /dev/ptmx
3. The '/dev/ptmx -> pts/ptmx' symlink is the preferred method since it
enables better error-reporting and treats both single-instance and
multi-instance mounts similarly.
But this method requires that system-startup scripts set the mode of
/dev/pts/ptmx correctly (default mode is 0000). The scripts can set the
mode by, either
- adding ptmxmode mount option to devpts entry in /etc/fstab, or
- using 'chmod 0666 /dev/pts/ptmx'
4. If multi-instance mode mount is needed for containers, but the system
startup scripts have not yet been updated, container-startup scripts
should bind mount /dev/ptmx to /dev/pts/ptmx to avoid breaking single-
instance mounts.
Or, in general, container-startup scripts should use:
mount -t devpts -o newinstance -o ptmxmode=0666 devpts /dev/pts
if [ ! -L /dev/ptmx ]; then
mount -o bind /dev/pts/ptmx /dev/ptmx
fi
When all devpts mounts are multi-instance, /dev/ptmx can permanently be
a symlink to pts/ptmx and the bind mount can be ignored.
5. A multi-instance mount that is not accompanied by the /dev/ptmx to
/dev/pts/ptmx redirection would result in an unusable/unreachable pty.
mount -t devpts -o newinstance lxcpts /dev/pts
immediately followed by:
open("/dev/ptmx")
would create a pty, say /dev/pts/7, in the initial kernel mount.
But /dev/pts/7 would be invisible in the new mount.
6. The permissions for /dev/pts/ptmx node should be specified when mounting
/dev/pts, using the '-o ptmxmode=%o' mount option (default is 0000).
mount -t devpts -o newinstance -o ptmxmode=0644 devpts /dev/pts
The permissions can be later be changed as usual with 'chmod'.
chmod 666 /dev/pts/ptmx
7. A mount of devpts without the 'newinstance' option results in binding to
initial kernel mount. This behavior while preserving legacy semantics,
does not provide strict isolation in a container environment. i.e by
mounting devpts without the 'newinstance' option, a container could
get visibility into the 'host' or root container's devpts.
To workaround this and have strict isolation, all mounts of devpts,
including the mount in the root container, should use the newinstance
option.

85
Documentation/filesystems/ext4.txt
View File

@ -58,13 +58,22 @@ Note: More extensive information for getting started with ext4 can be
# mount -t ext4 /dev/hda1 /wherever
- When comparing performance with other filesystems, remember that
ext3/4 by default offers higher data integrity guarantees than most.
So when comparing with a metadata-only journalling filesystem, such
as ext3, use `mount -o data=writeback'. And you might as well use
`mount -o nobh' too along with it. Making the journal larger than
the mke2fs default often helps performance with metadata-intensive
workloads.
- When comparing performance with other filesystems, it's always
important to try multiple workloads; very often a subtle change in a
workload parameter can completely change the ranking of which
filesystems do well compared to others. When comparing versus ext3,
note that ext4 enables write barriers by default, while ext3 does
not enable write barriers by default. So it is useful to use
explicitly specify whether barriers are enabled or not when via the
'-o barriers=[0|1]' mount option for both ext3 and ext4 filesystems
for a fair comparison. When tuning ext3 for best benchmark numbers,
it is often worthwhile to try changing the data journaling mode; '-o
data=writeback,nobh' can be faster for some workloads. (Note
however that running mounted with data=writeback can potentially
leave stale data exposed in recently written files in case of an
unclean shutdown, which could be a security exposure in some
situations.) Configuring the filesystem with a large journal can
also be helpful for metadata-intensive workloads.
2. Features
===========
@ -74,7 +83,7 @@ Note: More extensive information for getting started with ext4 can be
* ability to use filesystems > 16TB (e2fsprogs support not available yet)
* extent format reduces metadata overhead (RAM, IO for access, transactions)
* extent format more robust in face of on-disk corruption due to magics,
* internal redunancy in tree
* internal redundancy in tree
* improved file allocation (multi-block alloc)
* fix 32000 subdirectory limit
* nsec timestamps for mtime, atime, ctime, create time
@ -116,10 +125,11 @@ grouping of bitmaps and inode tables. Some test results available here:
When mounting an ext4 filesystem, the following option are accepted:
(*) == default
extents (*) ext4 will use extents to address file data. The
file system will no longer be mountable by ext3.
noextents ext4 will not use extents for newly created files
ro Mount filesystem read only. Note that ext4 will
replay the journal (and thus write to the
partition) even when mounted "read only". The
mount options "ro,noload" can be used to prevent
writes to the filesystem.
journal_checksum Enable checksumming of the journal transactions.
This will allow the recovery code in e2fsck and the
@ -134,17 +144,17 @@ journal_async_commit Commit block can be written to disk without waiting
journal=update Update the ext4 file system's journal to the current
format.
journal=inum When a journal already exists, this option is ignored.
Otherwise, it specifies the number of the inode which
will represent the ext4 file system's journal file.
journal_dev=devnum When the external journal device's major/minor numbers
have changed, this option allows the user to specify
the new journal location. The journal device is
identified through its new major/minor numbers encoded
in devnum.
noload Don't load the journal on mounting.
noload Don't load the journal on mounting. Note that
if the filesystem was not unmounted cleanly,
skipping the journal replay will lead to the
filesystem containing inconsistencies that can
lead to any number of problems.
data=journal All data are committed into the journal prior to being
written into the main file system.
@ -219,9 +229,12 @@ minixdf Make 'df' act like Minix.
debug Extra debugging information is sent to syslog.
errors=remount-ro(*) Remount the filesystem read-only on an error.
errors=remount-ro Remount the filesystem read-only on an error.
errors=continue Keep going on a filesystem error.
errors=panic Panic and halt the machine if an error occurs.
(These mount options override the errors behavior
specified in the superblock, which can be configured
using tune2fs)
data_err=ignore(*) Just print an error message if an error occurs
in a file data buffer in ordered mode.
@ -261,6 +274,42 @@ delalloc (*) Deferring block allocation until write-out time.
nodelalloc Disable delayed allocation. Blocks are allocation
when data is copied from user to page cache.
max_batch_time=usec Maximum amount of time ext4 should wait for
additional filesystem operations to be batch
together with a synchronous write operation.
Since a synchronous write operation is going to
force a commit and then a wait for the I/O
complete, it doesn't cost much, and can be a
huge throughput win, we wait for a small amount
of time to see if any other transactions can
piggyback on the synchronous write. The
algorithm used is designed to automatically tune
for the speed of the disk, by measuring the
amount of time (on average) that it takes to
finish committing a transaction. Call this time
the "commit time". If the time that the
transactoin has been running is less than the
commit time, ext4 will try sleeping for the
commit time to see if other operations will join
the transaction. The commit time is capped by
the max_batch_time, which defaults to 15000us
(15ms). This optimization can be turned off
entirely by setting max_batch_time to 0.
min_batch_time=usec This parameter sets the commit time (as
described above) to be at least min_batch_time.
It defaults to zero microseconds. Increasing
this parameter may improve the throughput of
multi-threaded, synchronous workloads on very
fast disks, at the cost of increasing latency.
journal_ioprio=prio The I/O priority (from 0 to 7, where 0 is the
highest priorty) which should be used for I/O
operations submitted by kjournald2 during a
commit operation. This defaults to 3, which is
a slightly higher priority than the default I/O
priority.
Data Mode
=========
There are 3 different data modes:

6
Documentation/filesystems/files.txt
View File

@ -76,13 +76,13 @@ the fdtable structure -
5. Handling of the file structures is special. Since the look-up
of the fd (fget()/fget_light()) are lock-free, it is possible
that look-up may race with the last put() operation on the
file structure. This is avoided using atomic_inc_not_zero()
file structure. This is avoided using atomic_long_inc_not_zero()
on ->f_count :
rcu_read_lock();
file = fcheck_files(files, fd);
if (file) {
if (atomic_inc_not_zero(&file->f_count))
if (atomic_long_inc_not_zero(&file->f_count))
*fput_needed = 1;
else
/* Didn't get the reference, someone's freed */
@ -92,7 +92,7 @@ the fdtable structure -
....
return file;
atomic_inc_not_zero() detects if refcounts is already zero or
atomic_long_inc_not_zero() detects if refcounts is already zero or
goes to zero during increment. If it does, we fail
fget()/fget_light().

3
Documentation/filesystems/ocfs2.txt
View File

@ -31,7 +31,6 @@ Features which OCFS2 does not support yet:
- quotas
- Directory change notification (F_NOTIFY)
- Distributed Caching (F_SETLEASE/F_GETLEASE/break_lease)
- POSIX ACLs
Mount options
=============
@ -79,3 +78,5 @@ inode64 Indicates that Ocfs2 is allowed to create inodes at
bits of significance.
user_xattr (*) Enables Extended User Attributes.
nouser_xattr Disables Extended User Attributes.
acl Enables POSIX Access Control Lists support.
noacl (*) Disables POSIX Access Control Lists support.

274
Documentation/filesystems/proc.txt
View File

@ -140,6 +140,7 @@ Table 1-1: Process specific entries in /proc
statm Process memory status information
status Process status in human readable form
wchan If CONFIG_KALLSYMS is set, a pre-decoded wchan
stack Report full stack trace, enable via CONFIG_STACKTRACE
smaps Extension based on maps, the rss size for each mapped file
..............................................................................
@ -1339,10 +1340,13 @@ nmi_watchdog
Enables/Disables the NMI watchdog on x86 systems. When the value is non-zero
the NMI watchdog is enabled and will continuously test all online cpus to
determine whether or not they are still functioning properly.
determine whether or not they are still functioning properly. Currently,
passing "nmi_watchdog=" parameter at boot time is required for this function
to work.
Because the NMI watchdog shares registers with oprofile, by disabling the NMI
watchdog, oprofile may have more registers to utilize.
If LAPIC NMI watchdog method is in use (nmi_watchdog=2 kernel parameter), the
NMI watchdog shares registers with oprofile. By disabling the NMI watchdog,
oprofile may have more registers to utilize.
msgmni
------
@ -1367,268 +1371,8 @@ auto_msgmni default value is 1.
2.4 /proc/sys/vm - The virtual memory subsystem
-----------------------------------------------
The files in this directory can be used to tune the operation of the virtual
memory (VM) subsystem of the Linux kernel.
vfs_cache_pressure
------------------
Controls the tendency of the kernel to reclaim the memory which is used for
caching of directory and inode objects.
At the default value of vfs_cache_pressure=100 the kernel will attempt to
reclaim dentries and inodes at a "fair" rate with respect to pagecache and
swapcache reclaim. Decreasing vfs_cache_pressure causes the kernel to prefer
to retain dentry and inode caches. Increasing vfs_cache_pressure beyond 100
causes the kernel to prefer to reclaim dentries and inodes.
dirty_background_ratio
----------------------
Contains, as a percentage of the dirtyable system memory (free pages + mapped
pages + file cache, not including locked pages and HugePages), the number of
pages at which the pdflush background writeback daemon will start writing out
dirty data.
dirty_ratio
-----------------
Contains, as a percentage of the dirtyable system memory (free pages + mapped
pages + file cache, not including locked pages and HugePages), the number of
pages at which a process which is generating disk writes will itself start
writing out dirty data.
dirty_writeback_centisecs
-------------------------
The pdflush writeback daemons will periodically wake up and write `old' data
out to disk. This tunable expresses the interval between those wakeups, in
100'ths of a second.
Setting this to zero disables periodic writeback altogether.
dirty_expire_centisecs
----------------------
This tunable is used to define when dirty data is old enough to be eligible
for writeout by the pdflush daemons. It is expressed in 100'ths of a second.
Data which has been dirty in-memory for longer than this interval will be
written out next time a pdflush daemon wakes up.
highmem_is_dirtyable
--------------------
Only present if CONFIG_HIGHMEM is set.
This defaults to 0 (false), meaning that the ratios set above are calculated
as a percentage of lowmem only. This protects against excessive scanning
in page reclaim, swapping and general VM distress.
Setting this to 1 can be useful on 32 bit machines where you want to make
random changes within an MMAPed file that is larger than your available
lowmem without causing large quantities of random IO. Is is safe if the
behavior of all programs running on the machine is known and memory will
not be otherwise stressed.
legacy_va_layout
----------------
If non-zero, this sysctl disables the new 32-bit mmap mmap layout - the kernel
will use the legacy (2.4) layout for all processes.
lowmem_reserve_ratio
---------------------
For some specialised workloads on highmem machines it is dangerous for
the kernel to allow process memory to be allocated from the "lowmem"
zone. This is because that memory could then be pinned via the mlock()
system call, or by unavailability of swapspace.
And on large highmem machines this lack of reclaimable lowmem memory
can be fatal.
So the Linux page allocator has a mechanism which prevents allocations
which _could_ use highmem from using too much lowmem. This means that
a certain amount of lowmem is defended from the possibility of being
captured into pinned user memory.
(The same argument applies to the old 16 megabyte ISA DMA region. This
mechanism will also defend that region from allocations which could use
highmem or lowmem).
The `lowmem_reserve_ratio' tunable determines how aggressive the kernel is
in defending these lower zones.
If you have a machine which uses highmem or ISA DMA and your
applications are using mlock(), or if you are running with no swap then
you probably should change the lowmem_reserve_ratio setting.
The lowmem_reserve_ratio is an array. You can see them by reading this file.
-
% cat /proc/sys/vm/lowmem_reserve_ratio
256 256 32
-
Note: # of this elements is one fewer than number of zones. Because the highest
zone's value is not necessary for following calculation.
But, these values are not used directly. The kernel calculates # of protection
pages for each zones from them. These are shown as array of protection pages
in /proc/zoneinfo like followings. (This is an example of x86-64 box).
Each zone has an array of protection pages like this.
-
Node 0, zone DMA
pages free 1355
min 3
low 3
high 4
:
:
numa_other 0
protection: (0, 2004, 2004, 2004)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
pagesets
cpu: 0 pcp: 0
:
-
These protections are added to score to judge whether this zone should be used
for page allocation or should be reclaimed.
In this example, if normal pages (index=2) are required to this DMA zone and
pages_high is used for watermark, the kernel judges this zone should not be
used because pages_free(1355) is smaller than watermark + protection[2]
(4 + 2004 = 2008). If this protection value is 0, this zone would be used for
normal page requirement. If requirement is DMA zone(index=0), protection[0]
(=0) is used.
zone[i]'s protection[j] is calculated by following expression.
(i < j):
zone[i]->protection[j]
= (total sums of present_pages from zone[i+1] to zone[j] on the node)
/ lowmem_reserve_ratio[i];
(i = j):
(should not be protected. = 0;
(i > j):
(not necessary, but looks 0)
The default values of lowmem_reserve_ratio[i] are
256 (if zone[i] means DMA or DMA32 zone)
32 (others).
As above expression, they are reciprocal number of ratio.
256 means 1/256. # of protection pages becomes about "0.39%" of total present
pages of higher zones on the node.
If you would like to protect more pages, smaller values are effective.
The minimum value is 1 (1/1 -> 100%).
page-cluster
------------
page-cluster controls the number of pages which are written to swap in
a single attempt. The swap I/O size.
It is a logarithmic value - setting it to zero means "1 page", setting
it to 1 means "2 pages", setting it to 2 means "4 pages", etc.
The default value is three (eight pages at a time). There may be some
small benefits in tuning this to a different value if your workload is
swap-intensive.
overcommit_memory
-----------------
Controls overcommit of system memory, possibly allowing processes
to allocate (but not use) more memory than is actually available.
0 - Heuristic overcommit handling. Obvious overcommits of
address space are refused. Used for a typical system. It
ensures a seriously wild allocation fails while allowing
overcommit to reduce swap usage. root is allowed to
allocate slightly more memory in this mode. This is the
default.
1 - Always overcommit. Appropriate for some scientific
applications.
2 - Don't overcommit. The total address space commit
for the system is not permitted to exceed swap plus a
configurable percentage (default is 50) of physical RAM.
Depending on the percentage you use, in most situations
this means a process will not be killed while attempting
to use already-allocated memory but will receive errors
on memory allocation as appropriate.
overcommit_ratio
----------------
Percentage of physical memory size to include in overcommit calculations
(see above.)
Memory allocation limit = swapspace + physmem * (overcommit_ratio / 100)
swapspace = total size of all swap areas
physmem = size of physical memory in system
nr_hugepages and hugetlb_shm_group
----------------------------------
nr_hugepages configures number of hugetlb page reserved for the system.
hugetlb_shm_group contains group id that is allowed to create SysV shared
memory segment using hugetlb page.
hugepages_treat_as_movable
--------------------------
This parameter is only useful when kernelcore= is specified at boot time to
create ZONE_MOVABLE for pages that may be reclaimed or migrated. Huge pages
are not movable so are not normally allocated from ZONE_MOVABLE. A non-zero
value written to hugepages_treat_as_movable allows huge pages to be allocated
from ZONE_MOVABLE.
Once enabled, the ZONE_MOVABLE is treated as an area of memory the huge
pages pool can easily grow or shrink within. Assuming that applications are
not running that mlock() a lot of memory, it is likely the huge pages pool
can grow to the size of ZONE_MOVABLE by repeatedly entering the desired value
into nr_hugepages and triggering page reclaim.
laptop_mode
-----------
laptop_mode is a knob that controls "laptop mode". All the things that are
controlled by this knob are discussed in Documentation/laptops/laptop-mode.txt.
block_dump
----------
block_dump enables block I/O debugging when set to a nonzero value. More
information on block I/O debugging is in Documentation/laptops/laptop-mode.txt.
swap_token_timeout
------------------
This file contains valid hold time of swap out protection token. The Linux
VM has token based thrashing control mechanism and uses the token to prevent
unnecessary page faults in thrashing situation. The unit of the value is
second. The value would be useful to tune thrashing behavior.
drop_caches
-----------
Writing to this will cause the kernel to drop clean caches, dentries and
inodes from memory, causing that memory to become free.
To free pagecache:
echo 1 > /proc/sys/vm/drop_caches
To free dentries and inodes:
echo 2 > /proc/sys/vm/drop_caches
To free pagecache, dentries and inodes:
echo 3 > /proc/sys/vm/drop_caches
As this is a non-destructive operation and dirty objects are not freeable, the
user should run `sync' first.
Please see: Documentation/sysctls/vm.txt for a description of these
entries.
2.5 /proc/sys/dev - Device specific parameters

225
Documentation/filesystems/squashfs.txt Normal file
View File

@ -0,0 +1,225 @@
SQUASHFS 4.0 FILESYSTEM
=======================
Squashfs is a compressed read-only filesystem for Linux.
It uses zlib compression to compress files, inodes and directories.
Inodes in the system are very small and all blocks are packed to minimise
data overhead. Block sizes greater than 4K are supported up to a maximum
of 1Mbytes (default block size 128K).
Squashfs is intended for general read-only filesystem use, for archival
use (i.e. in cases where a .tar.gz file may be used), and in constrained
block device/memory systems (e.g. embedded systems) where low overhead is
needed.
Mailing list: squashfs-devel@lists.sourceforge.net
Web site: www.squashfs.org
1. FILESYSTEM FEATURES
----------------------
Squashfs filesystem features versus Cramfs:
Squashfs Cramfs
Max filesystem size: 2^64 16 MiB
Max file size: ~ 2 TiB 16 MiB
Max files: unlimited unlimited
Max directories: unlimited unlimited
Max entries per directory: unlimited unlimited
Max block size: 1 MiB 4 KiB
Metadata compression: yes no
Directory indexes: yes no
Sparse file support: yes no
Tail-end packing (fragments): yes no
Exportable (NFS etc.): yes no
Hard link support: yes no
"." and ".." in readdir: yes no
Real inode numbers: yes no
32-bit uids/gids: yes no
File creation time: yes no
Xattr and ACL support: no no
Squashfs compresses data, inodes and directories. In addition, inode and
directory data are highly compacted, and packed on byte boundaries. Each
compressed inode is on average 8 bytes in length (the exact length varies on
file type, i.e. regular file, directory, symbolic link, and block/char device
inodes have different sizes).
2. USING SQUASHFS
-----------------
As squashfs is a read-only filesystem, the mksquashfs program must be used to
create populated squashfs filesystems. This and other squashfs utilities
can be obtained from http://www.squashfs.org. Usage instructions can be
obtained from this site also.
3. SQUASHFS FILESYSTEM DESIGN
-----------------------------
A squashfs filesystem consists of seven parts, packed together on a byte
alignment:
---------------
| superblock |
|---------------|
| datablocks |
| & fragments |
|---------------|
| inode table |
|---------------|
| directory |
| table |
|---------------|
| fragment |
| table |
|---------------|
| export |
| table |
|---------------|
| uid/gid |
| lookup table |
---------------
Compressed data blocks are written to the filesystem as files are read from
the source directory, and checked for duplicates. Once all file data has been
written the completed inode, directory, fragment, export and uid/gid lookup
tables are written.
3.1 Inodes
----------
Metadata (inodes and directories) are compressed in 8Kbyte blocks. Each
compressed block is prefixed by a two byte length, the top bit is set if the
block is uncompressed. A block will be uncompressed if the -noI option is set,
or if the compressed block was larger than the uncompressed block.
Inodes are packed into the metadata blocks, and are not aligned to block
boundaries, therefore inodes overlap compressed blocks. Inodes are identified
by a 48-bit number which encodes the location of the compressed metadata block
containing the inode, and the byte offset into that block where the inode is
placed (<block, offset>).
To maximise compression there are different inodes for each file type
(regular file, directory, device, etc.), the inode contents and length
varying with the type.
To further maximise compression, two types of regular file inode and
directory inode are defined: inodes optimised for frequently occurring
regular files and directories, and extended types where extra
information has to be stored.
3.2 Directories
---------------
Like inodes, directories are packed into compressed metadata blocks, stored
in a directory table. Directories are accessed using the start address of
the metablock containing the directory and the offset into the
decompressed block (<block, offset>).
Directories are organised in a slightly complex way, and are not simply
a list of file names. The organisation takes advantage of the
fact that (in most cases) the inodes of the files will be in the same
compressed metadata block, and therefore, can share the start block.
Directories are therefore organised in a two level list, a directory
header containing the shared start block value, and a sequence of directory
entries, each of which share the shared start block. A new directory header
is written once/if the inode start block changes. The directory
header/directory entry list is repeated as many times as necessary.
Directories are sorted, and can contain a directory index to speed up
file lookup. Directory indexes store one entry per metablock, each entry
storing the index/filename mapping to the first directory header
in each metadata block. Directories are sorted in alphabetical order,
and at lookup the index is scanned linearly looking for the first filename
alphabetically larger than the filename being looked up. At this point the
location of the metadata block the filename is in has been found.
The general idea of the index is ensure only one metadata block needs to be
decompressed to do a lookup irrespective of the length of the directory.
This scheme has the advantage that it doesn't require extra memory overhead
and doesn't require much extra storage on disk.
3.3 File data
-------------
Regular files consist of a sequence of contiguous compressed blocks, and/or a
compressed fragment block (tail-end packed block). The compressed size
of each datablock is stored in a block list contained within the
file inode.
To speed up access to datablocks when reading 'large' files (256 Mbytes or
larger), the code implements an index cache that caches the mapping from
block index to datablock location on disk.
The index cache allows Squashfs to handle large files (up to 1.75 TiB) while
retaining a simple and space-efficient block list on disk. The cache
is split into slots, caching up to eight 224 GiB files (128 KiB blocks).
Larger files use multiple slots, with 1.75 TiB files using all 8 slots.
The index cache is designed to be memory efficient, and by default uses
16 KiB.
3.4 Fragment lookup table
-------------------------
Regular files can contain a fragment index which is mapped to a fragment
location on disk and compressed size using a fragment lookup table. This
fragment lookup table is itself stored compressed into metadata blocks.
A second index table is used to locate these. This second index table for
speed of access (and because it is small) is read at mount time and cached
in memory.
3.5 Uid/gid lookup table
------------------------
For space efficiency regular files store uid and gid indexes, which are
converted to 32-bit uids/gids using an id look up table. This table is
stored compressed into metadata blocks. A second index table is used to
locate these. This second index table for speed of access (and because it
is small) is read at mount time and cached in memory.
3.6 Export table
----------------
To enable Squashfs filesystems to be exportable (via NFS etc.) filesystems
can optionally (disabled with the -no-exports Mksquashfs option) contain
an inode number to inode disk location lookup table. This is required to
enable Squashfs to map inode numbers passed in filehandles to the inode
location on disk, which is necessary when the export code reinstantiates
expired/flushed inodes.
This table is stored compressed into metadata blocks. A second index table is
used to locate these. This second index table for speed of access (and because
it is small) is read at mount time and cached in memory.
4. TODOS AND OUTSTANDING ISSUES
-------------------------------
4.1 Todo list
-------------
Implement Xattr and ACL support. The Squashfs 4.0 filesystem layout has hooks
for these but the code has not been written. Once the code has been written
the existing layout should not require modification.
4.2 Squashfs internal cache
---------------------------
Blocks in Squashfs are compressed. To avoid repeatedly decompressing
recently accessed data Squashfs uses two small metadata and fragment caches.
The cache is not used for file datablocks, these are decompressed and cached in
the page-cache in the normal way. The cache is used to temporarily cache
fragment and metadata blocks which have been read as a result of a metadata
(i.e. inode or directory) or fragment access. Because metadata and fragments
are packed together into blocks (to gain greater compression) the read of a
particular piece of metadata or fragment will retrieve other metadata/fragments
which have been packed with it, these because of locality-of-reference may be
read in the near future. Temporarily caching them ensures they are available
for near future access without requiring an additional read and decompress.
In the future this internal cache may be replaced with an implementation which
uses the kernel page cache. Because the page cache operates on page sized
units this may introduce additional complexity in terms of locking and
associated race conditions.

3
Documentation/filesystems/ubifs.txt
View File

@ -95,6 +95,9 @@ no_chk_data_crc skip checking of CRCs on data nodes in order to
of this option is that corruption of the contents
of a file can go unnoticed.
chk_data_crc (*) do not skip checking CRCs on data nodes
compr=none override default compressor and set it to "none"
compr=lzo override default compressor and set it to "lzo"
compr=zlib override default compressor and set it to "zlib"
Quick usage instructions

13
Documentation/filesystems/vfs.txt
View File

@ -210,8 +210,8 @@ struct super_operations {
void (*put_super) (struct super_block *);
void (*write_super) (struct super_block *);
int (*sync_fs)(struct super_block *sb, int wait);
void (*write_super_lockfs) (struct super_block *);
void (*unlockfs) (struct super_block *);
int (*freeze_fs) (struct super_block *);
int (*unfreeze_fs) (struct super_block *);
int (*statfs) (struct dentry *, struct kstatfs *);
int (*remount_fs) (struct super_block *, int *, char *);
void (*clear_inode) (struct inode *);
@ -270,11 +270,11 @@ or bottom half).
a superblock. The second parameter indicates whether the method
should wait until the write out has been completed. Optional.
write_super_lockfs: called when VFS is locking a filesystem and
freeze_fs: called when VFS is locking a filesystem and
forcing it into a consistent state. This method is currently
used by the Logical Volume Manager (LVM).
unlockfs: called when VFS is unlocking a filesystem and making it writable
unfreeze_fs: called when VFS is unlocking a filesystem and making it writable
again.
statfs: called when the VFS needs to get filesystem statistics. This
@ -733,7 +733,6 @@ struct file_operations {
ssize_t (*sendpage) (struct file *, struct page *, int, size_t, loff_t *, int);
unsigned long (*get_unmapped_area)(struct file *, unsigned long, unsigned long, unsigned long, unsigned long);
int (*check_flags)(int);
int (*dir_notify)(struct file *filp, unsigned long arg);
int (*flock) (struct file *, int, struct file_lock *);
ssize_t (*splice_write)(struct pipe_inode_info *, struct file *, size_t, unsigned int);
ssize_t (*splice_read)(struct file *, struct pipe_inode_info *, size_t, unsigned int);
@ -800,8 +799,6 @@ otherwise noted.
check_flags: called by the fcntl(2) system call for F_SETFL command
dir_notify: called by the fcntl(2) system call for F_NOTIFY command
flock: called by the flock(2) system call
splice_write: called by the VFS to splice data from a pipe to a file. This
@ -931,7 +928,7 @@ manipulate dentries:
d_lookup: look up a dentry given its parent and path name component
It looks up the child of that given name from the dcache
hash table. If it is found, the reference count is incremented
and the dentry is returned. The caller must use d_put()
and the dentry is returned. The caller must use dput()
to free the dentry when it finishes using it.
For further information on dentry locking, please refer to the document

4
Documentation/filesystems/xfs.txt
View File

@ -229,10 +229,6 @@ The following sysctls are available for the XFS filesystem:
ISGID bit is cleared if the irix_sgid_inherit compatibility sysctl
is set.
fs.xfs.restrict_chown (Min: 0 Default: 1 Max: 1)
Controls whether unprivileged users can use chown to "give away"
a file to another user.
fs.xfs.inherit_sync (Min: 0 Default: 1 Max: 1)
Setting this to "1" will cause the "sync" flag set
by the xfs_io(8) chattr command on a directory to be

149
Documentation/ftrace.txt
View File

@ -82,7 +82,7 @@ of ftrace. Here is a list of some of the key files:
tracer is not adding more data, they will display
the same information every time they are read.
iter_ctrl: This file lets the user control the amount of data
trace_options: This file lets the user control the amount of data
that is displayed in one of the above output
files.
@ -94,10 +94,10 @@ of ftrace. Here is a list of some of the key files:
only be recorded if the latency is greater than
the value in this file. (in microseconds)
trace_entries: This sets or displays the number of bytes each CPU
buffer_size_kb: This sets or displays the number of kilobytes each CPU
buffer can hold. The tracer buffers are the same size
for each CPU. The displayed number is the size of the
CPU buffer and not total size of all buffers. The
CPU buffer and not total size of all buffers. The
trace buffers are allocated in pages (blocks of memory
that the kernel uses for allocation, usually 4 KB in size).
If the last page allocated has room for more bytes
@ -127,6 +127,8 @@ of ftrace. Here is a list of some of the key files:
be traced. If a function exists in both set_ftrace_filter
and set_ftrace_notrace, the function will _not_ be traced.
set_ftrace_pid: Have the function tracer only trace a single thread.
available_filter_functions: This lists the functions that ftrace
has processed and can trace. These are the function
names that you can pass to "set_ftrace_filter" or
@ -316,23 +318,23 @@ The above is mostly meaningful for kernel developers.
The rest is the same as the 'trace' file.
iter_ctrl
---------
trace_options
-------------
The iter_ctrl file is used to control what gets printed in the trace
The trace_options file is used to control what gets printed in the trace
output. To see what is available, simply cat the file:
cat /debug/tracing/iter_ctrl
cat /debug/tracing/trace_options
print-parent nosym-offset nosym-addr noverbose noraw nohex nobin \
noblock nostacktrace nosched-tree
noblock nostacktrace nosched-tree nouserstacktrace nosym-userobj
To disable one of the options, echo in the option prepended with "no".
echo noprint-parent > /debug/tracing/iter_ctrl
echo noprint-parent > /debug/tracing/trace_options
To enable an option, leave off the "no".
echo sym-offset > /debug/tracing/iter_ctrl
echo sym-offset > /debug/tracing/trace_options
Here are the available options:
@ -378,6 +380,20 @@ Here are the available options:
When a trace is recorded, so is the stack of functions.
This allows for back traces of trace sites.
userstacktrace - This option changes the trace.
It records a stacktrace of the current userspace thread.
sym-userobj - when user stacktrace are enabled, look up which object the
address belongs to, and print a relative address
This is especially useful when ASLR is on, otherwise you don't
get a chance to resolve the address to object/file/line after the app is no
longer running
The lookup is performed when you read trace,trace_pipe,latency_trace. Example:
a.out-1623 [000] 40874.465068: /root/a.out[+0x480] <-/root/a.out[+0
x494] <- /root/a.out[+0x4a8] <- /lib/libc-2.7.so[+0x1e1a6]
sched-tree - TBD (any users??)
@ -1059,6 +1075,83 @@ For simple one time traces, the above is sufficent. For anything else,
a search through /proc/mounts may be needed to find where the debugfs
file-system is mounted.
Single thread tracing
---------------------
By writing into /debug/tracing/set_ftrace_pid you can trace a
single thread. For example:
# cat /debug/tracing/set_ftrace_pid
no pid
# echo 3111 > /debug/tracing/set_ftrace_pid
# cat /debug/tracing/set_ftrace_pid
3111
# echo function > /debug/tracing/current_tracer
# cat /debug/tracing/trace | head
# tracer: function
#
# TASK-PID CPU# TIMESTAMP FUNCTION
# | | | | |
yum-updatesd-3111 [003] 1637.254676: finish_task_switch <-thread_return
yum-updatesd-3111 [003] 1637.254681: hrtimer_cancel <-schedule_hrtimeout_range
yum-updatesd-3111 [003] 1637.254682: hrtimer_try_to_cancel <-hrtimer_cancel
yum-updatesd-3111 [003] 1637.254683: lock_hrtimer_base <-hrtimer_try_to_cancel
yum-updatesd-3111 [003] 1637.254685: fget_light <-do_sys_poll
yum-updatesd-3111 [003] 1637.254686: pipe_poll <-do_sys_poll
# echo -1 > /debug/tracing/set_ftrace_pid
# cat /debug/tracing/trace |head
# tracer: function
#
# TASK-PID CPU# TIMESTAMP FUNCTION
# | | | | |
##### CPU 3 buffer started ####
yum-updatesd-3111 [003] 1701.957688: free_poll_entry <-poll_freewait
yum-updatesd-3111 [003] 1701.957689: remove_wait_queue <-free_poll_entry
yum-updatesd-3111 [003] 1701.957691: fput <-free_poll_entry
yum-updatesd-3111 [003] 1701.957692: audit_syscall_exit <-sysret_audit
yum-updatesd-3111 [003] 1701.957693: path_put <-audit_syscall_exit
If you want to trace a function when executing, you could use
something like this simple program:
#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
int main (int argc, char **argv)
{
if (argc < 1)
exit(-1);
if (fork() > 0) {
int fd, ffd;
char line[64];
int s;
ffd = open("/debug/tracing/current_tracer", O_WRONLY);
if (ffd < 0)
exit(-1);
write(ffd, "nop", 3);
fd = open("/debug/tracing/set_ftrace_pid", O_WRONLY);
s = sprintf(line, "%d\n", getpid());
write(fd, line, s);
write(ffd, "function", 8);
close(fd);
close(ffd);
execvp(argv[1], argv+1);
}
return 0;
}
dynamic ftrace
--------------
@ -1158,7 +1251,11 @@ These are the only wild cards which are supported.
<match>*<match> will not work.
# echo hrtimer_* > /debug/tracing/set_ftrace_filter
Note: It is better to use quotes to enclose the wild cards, otherwise
the shell may expand the parameters into names of files in the local
directory.
# echo 'hrtimer_*' > /debug/tracing/set_ftrace_filter
Produces:
@ -1213,7 +1310,7 @@ Again, now we want to append.
# echo sys_nanosleep > /debug/tracing/set_ftrace_filter
# cat /debug/tracing/set_ftrace_filter
sys_nanosleep
# echo hrtimer_* >> /debug/tracing/set_ftrace_filter
# echo 'hrtimer_*' >> /debug/tracing/set_ftrace_filter
# cat /debug/tracing/set_ftrace_filter
hrtimer_run_queues
hrtimer_run_pending
@ -1299,41 +1396,29 @@ trace entries
-------------
Having too much or not enough data can be troublesome in diagnosing
an issue in the kernel. The file trace_entries is used to modify
an issue in the kernel. The file buffer_size_kb is used to modify
the size of the internal trace buffers. The number listed
is the number of entries that can be recorded per CPU. To know
the full size, multiply the number of possible CPUS with the
number of entries.
# cat /debug/tracing/trace_entries
65620
# cat /debug/tracing/buffer_size_kb
1408 (units kilobytes)
Note, to modify this, you must have tracing completely disabled. To do that,
echo "nop" into the current_tracer. If the current_tracer is not set
to "nop", an EINVAL error will be returned.
# echo nop > /debug/tracing/current_tracer
# echo 100000 > /debug/tracing/trace_entries
# cat /debug/tracing/trace_entries
100045
Notice that we echoed in 100,000 but the size is 100,045. The entries
are held in individual pages. It allocates the number of pages it takes
to fulfill the request. If more entries may fit on the last page
then they will be added.
# echo 1 > /debug/tracing/trace_entries
# cat /debug/tracing/trace_entries
85
This shows us that 85 entries can fit in a single page.
# echo 10000 > /debug/tracing/buffer_size_kb
# cat /debug/tracing/buffer_size_kb
10000 (units kilobytes)
The number of pages which will be allocated is limited to a percentage
of available memory. Allocating too much will produce an error.
# echo 1000000000000 > /debug/tracing/trace_entries
# echo 1000000000000 > /debug/tracing/buffer_size_kb
-bash: echo: write error: Cannot allocate memory
# cat /debug/tracing/trace_entries
# cat /debug/tracing/buffer_size_kb
85

10
Documentation/hwmon/abituguru-datasheet
View File

@ -74,7 +74,7 @@ a sensor.
Notice that some banks have both a read and a write address this is how the
uGuru determines if a read from or a write to the bank is taking place, thus
when reading you should always use the read address and when writing the
write address. The write address is always one (1) more then the read address.
write address. The write address is always one (1) more than the read address.
uGuru ready
@ -121,7 +121,7 @@ Once all bytes have been read data will hold 0x09, but there is no reason to
test for this. Notice that the number of bytes is bank address dependent see
above and below.
After completing a successfull read it is advised to put the uGuru back in
After completing a successful read it is advised to put the uGuru back in
ready mode, so that it is ready for the next read / write cycle. This way
if your program / driver is unloaded and later loaded again the detection
algorithm described above will still work.
@ -141,7 +141,7 @@ don't ask why this is the way it is.
Once DATA holds 0x01 read CMD it should hold 0xAC now.
After completing a successfull write it is advised to put the uGuru back in
After completing a successful write it is advised to put the uGuru back in
ready mode, so that it is ready for the next read / write cycle. This way
if your program / driver is unloaded and later loaded again the detection
algorithm described above will still work.
@ -224,7 +224,7 @@ Bit 3: Beep if alarm (RW)
Bit 4: 1 if alarm cause measured temp is over the warning threshold (R)
Bit 5: 1 if alarm cause measured volt is over the max threshold (R)
Bit 6: 1 if alarm cause measured volt is under the min threshold (R)
Bit 7: Volt sensor: Shutdown if alarm persist for more then 4 seconds (RW)
Bit 7: Volt sensor: Shutdown if alarm persist for more than 4 seconds (RW)
Temp sensor: Shutdown if temp is over the shutdown threshold (RW)
* This bit is only honored/used by the uGuru if a temp sensor is connected
@ -293,7 +293,7 @@ Byte 0:
Alarm behaviour for the selected sensor. A 1 enables the described behaviour.
Bit 0: Give an alarm if measured rpm is under the min threshold (RW)
Bit 3: Beep if alarm (RW)
Bit 7: Shutdown if alarm persist for more then 4 seconds (RW)
Bit 7: Shutdown if alarm persist for more than 4 seconds (RW)
Byte 1:
min threshold (scale as bank 0x26)

19
Documentation/hwmon/adt7470
View File

@ -31,15 +31,11 @@ Each of the measured inputs (temperature, fan speed) has corresponding high/low
limit values. The ADT7470 will signal an ALARM if any measured value exceeds
either limit.
The ADT7470 DOES NOT sample all inputs continuously. A single pin on the
ADT7470 is connected to a multitude of thermal diodes, but the chip must be
instructed explicitly to read the multitude of diodes. If you want to use
automatic fan control mode, you must manually read any of the temperature
sensors or the fan control algorithm will not run. The chip WILL NOT DO THIS
AUTOMATICALLY; this must be done from userspace. This may be a bug in the chip
design, given that many other AD chips take care of this. The driver will not
read the registers more often than once every 5 seconds. Further,
configuration data is only read once per minute.
The ADT7470 samples all inputs continuously. A kernel thread is started up for
the purpose of periodically querying the temperature sensors, thus allowing the
automatic fan pwm control to set the fan speed. The driver will not read the
registers more often than once every 5 seconds. Further, configuration data is
only read once per minute.
Special Features
----------------
@ -72,5 +68,6 @@ pwm#_auto_point2_temp.
Notes
-----
As stated above, the temperature inputs must be read periodically from
userspace in order for the automatic pwm algorithm to run.
The temperature inputs no longer need to be read periodically from userspace in
order for the automatic pwm algorithm to run. This was the case for earlier
versions of the driver.

87
Documentation/hwmon/adt7475 Normal file
View File

@ -0,0 +1,87 @@
This describes the interface for the ADT7475 driver:
(there are 4 fans, numbered fan1 to fan4):
fanX_input Read the current speed of the fan (in RPMs)
fanX_min Read/write the minimum speed of the fan. Dropping
below this sets an alarm.
(there are three PWMs, numbered pwm1 to pwm3):
pwmX Read/write the current duty cycle of the PWM. Writes
only have effect when auto mode is turned off (see
below). Range is 0 - 255.
pwmX_enable Fan speed control method:
0 - No control (fan at full speed)
1 - Manual fan speed control (using pwm[1-*])
2 - Automatic fan speed control
pwmX_auto_channels_temp Select which channels affect this PWM
1 - TEMP1 controls PWM
2 - TEMP2 controls PWM
4 - TEMP3 controls PWM
6 - TEMP2 and TEMP3 control PWM
7 - All three inputs control PWM
pwmX_freq Read/write the PWM frequency in Hz. The number
should be one of the following:
11 Hz
14 Hz
22 Hz
29 Hz
35 Hz
44 Hz
58 Hz
88 Hz
pwmX_auto_point1_pwm Read/write the minimum PWM duty cycle in automatic mode
pwmX_auto_point2_pwm Read/write the maximum PWM duty cycle in automatic mode
(there are three temperature settings numbered temp1 to temp3):
tempX_input Read the current temperature. The value is in milli
degrees of Celsius.
tempX_max Read/write the upper temperature limit - exceeding this
will cause an alarm.
tempX_min Read/write the lower temperature limit - exceeding this
will cause an alarm.
tempX_offset Read/write the temperature adjustment offset
tempX_crit Read/write the THERM limit for remote1.
tempX_crit_hyst Set the temperature value below crit where the
fans will stay on - this helps drive the temperature
low enough so it doesn't stay near the edge and
cause THERM to keep tripping.
tempX_auto_point1_temp Read/write the minimum temperature where the fans will
turn on in automatic mode.
tempX_auto_point2_temp Read/write the maximum temperature over which the fans
will run in automatic mode. tempX_auto_point1_temp
and tempX_auto_point2_temp together define the
range of automatic control.
tempX_alarm Read a 1 if the max/min alarm is set
tempX_fault Read a 1 if either temp1 or temp3 diode has a fault
(There are two voltage settings, in1 and in2):
inX_input Read the current voltage on VCC. Value is in
millivolts.
inX_min read/write the minimum voltage limit.
Dropping below this causes an alarm.
inX_max read/write the maximum voltage limit.
Exceeding this causes an alarm.
inX_alarm Read a 1 if the max/min alarm is set.

89
Documentation/hwmon/f71882fg Normal file
View File

@ -0,0 +1,89 @@
Kernel driver f71882fg
======================
Supported chips:
* Fintek F71882FG and F71883FG
Prefix: 'f71882fg'
Addresses scanned: none, address read from Super I/O config space
Datasheet: Available from the Fintek website
* Fintek F71862FG and F71863FG
Prefix: 'f71862fg'
Addresses scanned: none, address read from Super I/O config space
Datasheet: Available from the Fintek website
* Fintek F8000
Prefix: 'f8000'
Addresses scanned: none, address read from Super I/O config space
Datasheet: Not public
Author: Hans de Goede <hdegoede@redhat.com>
Description
-----------
Fintek F718xxFG/F8000 Super I/O chips include complete hardware monitoring
capabilities. They can monitor up to 9 voltages (3 for the F8000), 4 fans and
3 temperature sensors.
These chips also have fan controlling features, using either DC or PWM, in
three different modes (one manual, two automatic).
The driver assumes that no more than one chip is present, which seems
reasonable.
Monitoring
----------
The Voltage, Fan and Temperature Monitoring uses the standard sysfs
interface as documented in sysfs-interface, without any exceptions.
Fan Control
-----------
Both PWM (pulse-width modulation) and DC fan speed control methods are
supported. The right one to use depends on external circuitry on the
motherboard, so the driver assumes that the BIOS set the method
properly.
There are 2 modes to specify the speed of the fan, PWM duty cycle (or DC
voltage) mode, where 0-100% duty cycle (0-100% of 12V) is specified. And RPM
mode where the actual RPM of the fan (as measured) is controlled and the speed
gets specified as 0-100% of the fan#_full_speed file.
Since both modes work in a 0-100% (mapped to 0-255) scale, there isn't a
whole lot of a difference when modifying fan control settings. The only
important difference is that in RPM mode the 0-100% controls the fan speed
between 0-100% of fan#_full_speed. It is assumed that if the BIOS programs
RPM mode, it will also set fan#_full_speed properly, if it does not then
fan control will not work properly, unless you set a sane fan#_full_speed
value yourself.
Switching between these modes requires re-initializing a whole bunch of
registers, so the mode which the BIOS has set is kept. The mode is
printed when loading the driver.
Three different fan control modes are supported; the mode number is written
to the pwm#_enable file. Note that not all modes are supported on all
chips, and some modes may only be available in RPM / PWM mode on the F8000.
Writing an unsupported mode will result in an invalid parameter error.
* 1: Manual mode
You ask for a specific PWM duty cycle / DC voltage or a specific % of
fan#_full_speed by writing to the pwm# file. This mode is only
available on the F8000 if the fan channel is in RPM mode.
* 2: Normal auto mode
You can define a number of temperature/fan speed trip points, which % the
fan should run at at this temp and which temp a fan should follow using the
standard sysfs interface. The number and type of trip points is chip
depended, see which files are available in sysfs.
Fan/PWM channel 3 of the F8000 is always in this mode!
* 3: Thermostat mode (Only available on the F8000 when in duty cycle mode)
The fan speed is regulated to keep the temp the fan is mapped to between
temp#_auto_point2_temp and temp#_auto_point3_temp.
Both of the automatic modes require that pwm1 corresponds to fan1, pwm2 to
fan2 and pwm3 to fan3.

20
Documentation/hwmon/it87
View File

@ -26,6 +26,10 @@ Supported chips:
Datasheet: Publicly available at the ITE website
http://www.ite.com.tw/product_info/file/pc/IT8718F_V0.2.zip
http://www.ite.com.tw/product_info/file/pc/IT8718F_V0%203_(for%20C%20version).zip
* IT8720F
Prefix: 'it8720'
Addresses scanned: from Super I/O config space (8 I/O ports)
Datasheet: Not yet publicly available.
* SiS950 [clone of IT8705F]
Prefix: 'it87'
Addresses scanned: from Super I/O config space (8 I/O ports)
@ -71,7 +75,7 @@ Description
-----------
This driver implements support for the IT8705F, IT8712F, IT8716F,
IT8718F, IT8726F and SiS950 chips.
IT8718F, IT8720F, IT8726F and SiS950 chips.
These chips are 'Super I/O chips', supporting floppy disks, infrared ports,
joysticks and other miscellaneous stuff. For hardware monitoring, they
@ -84,19 +88,19 @@ the IT8716F and late IT8712F have 6. They are shared with other functions
though, so the functionality may not be available on a given system.
The driver dumbly assume it is there.
The IT8718F also features VID inputs (up to 8 pins) but the value is
stored in the Super-I/O configuration space. Due to technical limitations,
The IT8718F and IT8720F also features VID inputs (up to 8 pins) but the value
is stored in the Super-I/O configuration space. Due to technical limitations,
this value can currently only be read once at initialization time, so
the driver won't notice and report changes in the VID value. The two
upper VID bits share their pins with voltage inputs (in5 and in6) so you
can't have both on a given board.
The IT8716F, IT8718F and later IT8712F revisions have support for
The IT8716F, IT8718F, IT8720F and later IT8712F revisions have support for
2 additional fans. The additional fans are supported by the driver.
The IT8716F and IT8718F, and late IT8712F and IT8705F also have optional
16-bit tachometer counters for fans 1 to 3. This is better (no more fan
clock divider mess) but not compatible with the older chips and
The IT8716F, IT8718F and IT8720F, and late IT8712F and IT8705F also have
optional 16-bit tachometer counters for fans 1 to 3. This is better (no more
fan clock divider mess) but not compatible with the older chips and
revisions. The 16-bit tachometer mode is enabled by the driver when one
of the above chips is detected.
@ -122,7 +126,7 @@ zero'; this is important for negative voltage measurements. All voltage
inputs can measure voltages between 0 and 4.08 volts, with a resolution of
0.016 volt. The battery voltage in8 does not have limit registers.
The VID lines (IT8712F/IT8716F/IT8718F) encode the core voltage value:
The VID lines (IT8712F/IT8716F/IT8718F/IT8720F) encode the core voltage value:
the voltage level your processor should work with. This is hardcoded by
the mainboard and/or processor itself. It is a value in volts.

30
Documentation/hwmon/lis3lv02d
View File

@ -13,18 +13,21 @@ Author:
Description
-----------
This driver provides support for the accelerometer found in various HP laptops
sporting the feature officially called "HP Mobile Data Protection System 3D" or
"HP 3D DriveGuard". It detect automatically laptops with this sensor. Known models
(for now the HP 2133, nc6420, nc2510, nc8510, nc84x0, nw9440 and nx9420) will
have their axis automatically oriented on standard way (eg: you can directly
play neverball). The accelerometer data is readable via
This driver provides support for the accelerometer found in various HP
laptops sporting the feature officially called "HP Mobile Data
Protection System 3D" or "HP 3D DriveGuard". It detect automatically
laptops with this sensor. Known models (for now the HP 2133, nc6420,
nc2510, nc8510, nc84x0, nw9440 and nx9420) will have their axis
automatically oriented on standard way (eg: you can directly play
neverball). The accelerometer data is readable via
/sys/devices/platform/lis3lv02d.
Sysfs attributes under /sys/devices/platform/lis3lv02d/:
position - 3D position that the accelerometer reports. Format: "(x,y,z)"
calibrate - read: values (x, y, z) that are used as the base for input class device operation.
write: forces the base to be recalibrated with the current position.
calibrate - read: values (x, y, z) that are used as the base for input
class device operation.
write: forces the base to be recalibrated with the current
position.
rate - reports the sampling rate of the accelerometer device in HZ
This driver also provides an absolute input class device, allowing
@ -39,11 +42,12 @@ the accelerometer are converted into a "standard" organisation of the axes
* When the laptop is horizontal the position reported is about 0 for X and Y
and a positive value for Z
* If the left side is elevated, X increases (becomes positive)
* If the front side (where the touchpad is) is elevated, Y decreases (becomes negative)
* If the front side (where the touchpad is) is elevated, Y decreases
(becomes negative)
* If the laptop is put upside-down, Z becomes negative
If your laptop model is not recognized (cf "dmesg"), you can send an email to the
authors to add it to the database. When reporting a new laptop, please include
the output of "dmidecode" plus the value of /sys/devices/platform/lis3lv02d/position
in these four cases.
If your laptop model is not recognized (cf "dmesg"), you can send an
email to the authors to add it to the database. When reporting a new
laptop, please include the output of "dmidecode" plus the value of
/sys/devices/platform/lis3lv02d/position in these four cases.

12
Documentation/hwmon/lm70
View File

@ -1,9 +1,11 @@
Kernel driver lm70
==================
Supported chip:
Supported chips:
* National Semiconductor LM70
Datasheet: http://www.national.com/pf/LM/LM70.html
* Texas Instruments TMP121/TMP123
Information: http://focus.ti.com/docs/prod/folders/print/tmp121.html
Author:
Kaiwan N Billimoria <kaiwan@designergraphix.com>
@ -25,6 +27,14 @@ complement digital temperature (sent via the SIO line), is available in the
driver for interpretation. This driver makes use of the kernel's in-core
SPI support.
As a real (in-tree) example of this "SPI protocol driver" interfacing
with a "SPI master controller driver", see drivers/spi/spi_lm70llp.c
and its associated documentation.
The TMP121/TMP123 are very similar; main differences are 4 wire SPI inter-
face (read only) and 13-bit temperature data (0.0625 degrees celsius reso-
lution).
Thanks to
---------
Jean Delvare <khali@linux-fr.org> for mentoring the hwmon-side driver

2
Documentation/hwmon/lm85
View File

@ -164,7 +164,7 @@ configured individually according to the following options.
temperature. (PWM value from 0 to 255)
* pwm#_auto_pwm_minctl - this flags selects for temp#_auto_temp_off temperature
the bahaviour of fans. Write 1 to let fans spinning at
the behaviour of fans. Write 1 to let fans spinning at
pwm#_auto_pwm_min or write 0 to let them off.
NOTE: It has been reported that there is a bug in the LM85 that causes the flag

81
Documentation/hwmon/ltc4245 Normal file
View File

@ -0,0 +1,81 @@
Kernel driver ltc4245
=====================
Supported chips:
* Linear Technology LTC4245
Prefix: 'ltc4245'
Addresses scanned: 0x20-0x3f
Datasheet:
http://www.linear.com/pc/downloadDocument.do?navId=H0,C1,C1003,C1006,C1140,P19392,D13517
Author: Ira W. Snyder <iws@ovro.caltech.edu>
Description
-----------
The LTC4245 controller allows a board to be safely inserted and removed
from a live backplane in multiple supply systems such as CompactPCI and
PCI Express.
Usage Notes
-----------
This driver does not probe for LTC4245 devices, due to the fact that some
of the possible addresses are unfriendly to probing. You will need to use
the "force" parameter to tell the driver where to find the device.
Example: the following will load the driver for an LTC4245 at address 0x23
on I2C bus #1:
$ modprobe ltc4245 force=1,0x23
Sysfs entries
-------------
The LTC4245 has built-in limits for over and under current warnings. This
makes it very likely that the reference circuit will be used.
This driver uses the values in the datasheet to change the register values
into the values specified in the sysfs-interface document. The current readings
rely on the sense resistors listed in Table 2: "Sense Resistor Values".
in1_input 12v input voltage (mV)
in2_input 5v input voltage (mV)
in3_input 3v input voltage (mV)
in4_input Vee (-12v) input voltage (mV)
in1_min_alarm 12v input undervoltage alarm
in2_min_alarm 5v input undervoltage alarm
in3_min_alarm 3v input undervoltage alarm
in4_min_alarm Vee (-12v) input undervoltage alarm
curr1_input 12v current (mA)
curr2_input 5v current (mA)
curr3_input 3v current (mA)
curr4_input Vee (-12v) current (mA)
curr1_max_alarm 12v overcurrent alarm
curr2_max_alarm 5v overcurrent alarm
curr3_max_alarm 3v overcurrent alarm
curr4_max_alarm Vee (-12v) overcurrent alarm
in5_input 12v output voltage (mV)
in6_input 5v output voltage (mV)
in7_input 3v output voltage (mV)
in8_input Vee (-12v) output voltage (mV)
in5_min_alarm 12v output undervoltage alarm
in6_min_alarm 5v output undervoltage alarm
in7_min_alarm 3v output undervoltage alarm
in8_min_alarm Vee (-12v) output undervoltage alarm
in9_input GPIO #1 voltage data
in10_input GPIO #2 voltage data
in11_input GPIO #3 voltage data
power1_input 12v power usage (mW)
power2_input 5v power usage (mW)
power3_input 3v power usage (mW)
power4_input Vee (-12v) power usage (mW)

5
Documentation/ide/warm-plug-howto.txt
View File

@ -11,3 +11,8 @@ unplug old device(s) and plug new device(s)
# echo -n "1" > /sys/class/ide_port/idex/scan
done
NOTE: please make sure that partitions are unmounted and that there are
no other active references to devices before doing "delete_devices" step,
also do not attempt "scan" step on devices currently in use -- otherwise
results may be unpredictable and lead to data loss if you're unlucky

109
Documentation/input/walkera0701.txt Normal file
View File

@ -0,0 +1,109 @@
Walkera WK-0701 transmitter is supplied with a ready to fly Walkera
helicopters such as HM36, HM37, HM60. The walkera0701 module enables to use
this transmitter as joystick
Devel homepage and download:
http://zub.fei.tuke.sk/walkera-wk0701/
or use cogito:
cg-clone http://zub.fei.tuke.sk/GIT/walkera0701-joystick
Connecting to PC:
At back side of transmitter S-video connector can be found. Modulation
pulses from processor to HF part can be found at pin 2 of this connector,
pin 3 is GND. Between pin 3 and CPU 5k6 resistor can be found. To get
modulation pulses to PC, signal pulses must be amplified.
Cable: (walkera TX to parport)
Walkera WK-0701 TX S-VIDEO connector:
(back side of TX)
__ __ S-video: canon25
/ |_| \ pin 2 (signal) NPN parport
/ O 4 3 O \ pin 3 (GND) LED ________________ 10 ACK
( O 2 1 O ) | C
\ ___ / 2 ________________________|\|_____|/
| [___] | |/| B |\
------- 3 __________________________________|________________ 25 GND
E
I use green LED and BC109 NPN transistor.
Software:
Build kernel with walkera0701 module. Module walkera0701 need exclusive
access to parport, modules like lp must be unloaded before loading
walkera0701 module, check dmesg for error messages. Connect TX to PC by
cable and run jstest /dev/input/js0 to see values from TX. If no value can
be changed by TX "joystick", check output from /proc/interrupts. Value for
(usually irq7) parport must increase if TX is on.
Technical details:
Driver use interrupt from parport ACK input bit to measure pulse length
using hrtimers.
Frame format:
Based on walkera WK-0701 PCM Format description by Shaul Eizikovich.
(downloaded from http://www.smartpropoplus.com/Docs/Walkera_Wk-0701_PCM.pdf)
Signal pulses:
(ANALOG)
SYNC BIN OCT
+---------+ +------+
| | | |
--+ +------+ +---
Frame:
SYNC , BIN1, OCT1, BIN2, OCT2 ... BIN24, OCT24, BIN25, next frame SYNC ..
pulse length:
Binary values: Analog octal values:
288 uS Binary 0 318 uS 000
438 uS Binary 1 398 uS 001
478 uS 010
558 uS 011
638 uS 100
1306 uS SYNC 718 uS 101
798 uS 110
878 uS 111
24 bin+oct values + 1 bin value = 24*4+1 bits = 97 bits
(Warning, pulses on ACK ar inverted by transistor, irq is rised up on sync
to bin change or octal value to bin change).
Binary data representations:
One binary and octal value can be grouped to nibble. 24 nibbles + one binary
values can be sampled between sync pulses.
Values for first four channels (analog joystick values) can be found in
first 10 nibbles. Analog value is represented by one sign bit and 9 bit
absolute binary value. (10 bits per channel). Next nibble is checksum for
first ten nibbles.
Next nibbles 12 .. 21 represents four channels (not all channels can be
directly controlled from TX). Binary representations ar the same as in first
four channels. In nibbles 22 and 23 is a special magic number. Nibble 24 is
checksum for nibbles 12..23.
After last octal value for nibble 24 and next sync pulse one additional
binary value can be sampled. This bit and magic number is not used in
software driver. Some details about this magic numbers can be found in
Walkera_Wk-0701_PCM.pdf.
Checksum calculation:
Summary of octal values in nibbles must be same as octal value in checksum
nibble (only first 3 bits are used). Binary value for checksum nibble is
calculated by sum of binary values in checked nibbles + sum of octal values
in checked nibbles divided by 8. Only bit 0 of this sum is used.

12
Documentation/ioctl/ioctl-number.txt
View File

@ -84,7 +84,7 @@ Code Seq# Include File Comments
'B' C0-FF advanced bbus
<mailto:maassen@uni-freiburg.de>
'C' all linux/soundcard.h
'D' all asm-s390/dasd.h
'D' all arch/s390/include/asm/dasd.h
'E' all linux/input.h
'F' all linux/fb.h
'H' all linux/hiddev.h
@ -97,6 +97,7 @@ Code Seq# Include File Comments
<http://linux01.gwdg.de/~alatham/ppdd.html>
'M' all linux/soundcard.h
'N' 00-1F drivers/usb/scanner.h
'O' 00-02 include/mtd/ubi-user.h UBI
'P' all linux/soundcard.h
'Q' all linux/soundcard.h
'R' 00-1F linux/random.h
@ -104,7 +105,7 @@ Code Seq# Include File Comments
'S' 80-81 scsi/scsi_ioctl.h conflict!
'S' 82-FF scsi/scsi.h conflict!
'T' all linux/soundcard.h conflict!
'T' all asm-i386/ioctls.h conflict!
'T' all arch/x86/include/asm/ioctls.h conflict!
'U' 00-EF linux/drivers/usb/usb.h
'V' all linux/vt.h
'W' 00-1F linux/watchdog.h conflict!
@ -119,7 +120,7 @@ Code Seq# Include File Comments
<mailto:natalia@nikhefk.nikhef.nl>
'c' 00-7F linux/comstats.h conflict!
'c' 00-7F linux/coda.h conflict!
'c' 80-9F asm-s390/chsc.h
'c' 80-9F arch/s390/include/asm/chsc.h
'd' 00-FF linux/char/drm/drm/h conflict!
'd' 00-DF linux/video_decoder.h conflict!
'd' F0-FF linux/digi1.h
@ -142,6 +143,9 @@ Code Seq# Include File Comments
'n' 00-7F linux/ncp_fs.h
'n' E0-FF video/matrox.h matroxfb
'o' 00-1F fs/ocfs2/ocfs2_fs.h OCFS2
'o' 00-03 include/mtd/ubi-user.h conflict! (OCFS2 and UBI overlaps)
'o' 40-41 include/mtd/ubi-user.h UBI
'o' 01-A1 include/linux/dvb/*.h DVB
'p' 00-0F linux/phantom.h conflict! (OpenHaptics needs this)
'p' 00-3F linux/mc146818rtc.h conflict!
'p' 40-7F linux/nvram.h
@ -166,7 +170,7 @@ Code Seq# Include File Comments
<mailto:oe@port.de>
0x80 00-1F linux/fb.h
0x81 00-1F linux/videotext.h
0x89 00-06 asm-i386/sockios.h
0x89 00-06 arch/x86/include/asm/sockios.h
0x89 0B-DF linux/sockios.h
0x89 E0-EF linux/sockios.h SIOCPROTOPRIVATE range
0x89 F0-FF linux/sockios.h SIOCDEVPRIVATE range

6
Documentation/kbuild/00-INDEX
View File

@ -1,5 +1,9 @@
00-INDEX
- this file: info on the kernel build process
- this file: info on the kernel build process
kbuild.txt
- developer information on kbuild
kconfig.txt
- usage help for make *config
kconfig-language.txt
- specification of Config Language, the language in Kconfig files
makefiles.txt

133
Documentation/kbuild/kbuild.txt Normal file
View File

@ -0,0 +1,133 @@
Environment variables
KCPPFLAGS
--------------------------------------------------
Additional options to pass when preprocessing. The preprocessing options
will be used in all cases where kbuild do preprocessing including
building C files and assembler files.
KAFLAGS
--------------------------------------------------
Additional options to the assembler.
KCFLAGS
--------------------------------------------------
Additional options to the C compiler.
KBUILD_VERBOSE
--------------------------------------------------
Set the kbuild verbosity. Can be assinged same values as "V=...".
See make help for the full list.
Setting "V=..." takes precedence over KBUILD_VERBOSE.
KBUILD_EXTMOD
--------------------------------------------------
Set the directory to look for the kernel source when building external
modules.
The directory can be specified in several ways:
1) Use "M=..." on the command line
2) Environmnet variable KBUILD_EXTMOD
3) Environmnet variable SUBDIRS
The possibilities are listed in the order they take precedence.
Using "M=..." will always override the others.
KBUILD_OUTPUT
--------------------------------------------------
Specify the output directory when building the kernel.
The output directory can also be specificed using "O=...".
Setting "O=..." takes precedence over KBUILD_OUTPUT
ARCH
--------------------------------------------------
Set ARCH to the architecture to be built.
In most cases the name of the architecture is the same as the
directory name found in the arch/ directory.
But some architectures suach as x86 and sparc has aliases.
x86: i386 for 32 bit, x86_64 for 64 bit
sparc: sparc for 32 bit, sparc64 for 64 bit
CROSS_COMPILE
--------------------------------------------------
Specify an optional fixed part of the binutils filename.
CROSS_COMPILE can be a part of the filename or the full path.
CROSS_COMPILE is also used for ccache is some setups.
CF
--------------------------------------------------
Additional options for sparse.
CF is often used on the command-line like this:
make CF=-Wbitwise C=2
INSTALL_PATH
--------------------------------------------------
INSTALL_PATH specifies where to place the updated kernel and system map
images. Default is /boot, but you can set it to other values
MODLIB
--------------------------------------------------
Specify where to install modules.
The default value is:
$(INSTALL_MOD_PATH)/lib/modules/$(KERNELRELEASE)
The value can be overridden in which case the default value is ignored.
INSTALL_MOD_PATH
--------------------------------------------------
INSTALL_MOD_PATH specifies a prefix to MODLIB for module directory
relocations required by build roots. This is not defined in the
makefile but the argument can be passed to make if needed.
INSTALL_MOD_STRIP
--------------------------------------------------
INSTALL_MOD_STRIP, if defined, will cause modules to be
stripped after they are installed. If INSTALL_MOD_STRIP is '1', then
the default option --strip-debug will be used. Otherwise,
INSTALL_MOD_STRIP will used as the options to the strip command.
INSTALL_FW_PATH
--------------------------------------------------
INSTALL_FW_PATH specify where to install the firmware blobs.
The default value is:
$(INSTALL_MOD_PATH)/lib/firmware
The value can be overridden in which case the default value is ignored.
INSTALL_HDR_PATH
--------------------------------------------------
INSTALL_HDR_PATH specify where to install user space headers when
executing "make headers_*".
The default value is:
$(objtree)/usr
$(objtree) is the directory where output files are saved.
The output directory is often set using "O=..." on the commandline.
The value can be overridden in which case the default value is ignored.
KBUILD_MODPOST_WARN
--------------------------------------------------
KBUILD_MODPOST_WARN can be set to avoid error out in case of undefined
symbols in the final module linking stage.
KBUILD_MODPOST_FINAL
--------------------------------------------------
KBUILD_MODPOST_NOFINAL can be set to skip the final link of modules.
This is solely usefull to speed up test compiles.
KBUILD_EXTRA_SYMBOLS
--------------------------------------------------
For modules use symbols from another modules.
See more details in modules.txt.
ALLSOURCE_ARCHS
--------------------------------------------------
For tags/TAGS/cscope targets, you can specify more than one archs
to be included in the databases, separated by blankspace. e.g.
$ make ALLSOURCE_ARCHS="x86 mips arm" tags

188
Documentation/kbuild/kconfig.txt Normal file
View File

@ -0,0 +1,188 @@
This file contains some assistance for using "make *config".
Use "make help" to list all of the possible configuration targets.
The xconfig ('qconf') and menuconfig ('mconf') programs also
have embedded help text. Be sure to check it for navigation,
search, and other general help text.
======================================================================
General
--------------------------------------------------
New kernel releases often introduce new config symbols. Often more
important, new kernel releases may rename config symbols. When
this happens, using a previously working .config file and running
"make oldconfig" won't necessarily produce a working new kernel
for you, so you may find that you need to see what NEW kernel
symbols have been introduced.
To see a list of new config symbols when using "make oldconfig", use
cp user/some/old.config .config
yes "" | make oldconfig >conf.new
and the config program will list as (NEW) any new symbols that have
unknown values. Of course, the .config file is also updated with
new (default) values, so you can use:
grep "(NEW)" conf.new
to see the new config symbols or you can 'diff' the previous and
new .config files to see the differences:
diff .config.old .config | less
(Yes, we need something better here.)
======================================================================
menuconfig
--------------------------------------------------
SEARCHING for CONFIG symbols
Searching in menuconfig:
The Search function searches for kernel configuration symbol
names, so you have to know something close to what you are
looking for.
Example:
/hotplug
This lists all config symbols that contain "hotplug",
e.g., HOTPLUG, HOTPLUG_CPU, MEMORY_HOTPLUG.
For search help, enter / followed TAB-TAB-TAB (to highlight
<Help>) and Enter. This will tell you that you can also use
regular expressions (regexes) in the search string, so if you
are not interested in MEMORY_HOTPLUG, you could try
/^hotplug
______________________________________________________________________
Color Themes for 'menuconfig'
It is possible to select different color themes using the variable
MENUCONFIG_COLOR. To select a theme use:
make MENUCONFIG_COLOR=<theme> menuconfig
Available themes are:
mono => selects colors suitable for monochrome displays
blackbg => selects a color scheme with black background
classic => theme with blue background. The classic look
bluetitle => a LCD friendly version of classic. (default)
______________________________________________________________________
Environment variables in 'menuconfig'
KCONFIG_ALLCONFIG
--------------------------------------------------
(partially based on lkml email from/by Rob Landley, re: miniconfig)
--------------------------------------------------
The allyesconfig/allmodconfig/allnoconfig/randconfig variants can
also use the environment variable KCONFIG_ALLCONFIG as a flag or a
filename that contains config symbols that the user requires to be
set to a specific value. If KCONFIG_ALLCONFIG is used without a
filename, "make *config" checks for a file named
"all{yes/mod/no/random}.config" (corresponding to the *config command
that was used) for symbol values that are to be forced. If this file
is not found, it checks for a file named "all.config" to contain forced
values.
This enables you to create "miniature" config (miniconfig) or custom
config files containing just the config symbols that you are interested
in. Then the kernel config system generates the full .config file,
including dependencies of your miniconfig file, based on the miniconfig
file.
This 'KCONFIG_ALLCONFIG' file is a config file which contains
(usually a subset of all) preset config symbols. These variable
settings are still subject to normal dependency checks.
Examples:
KCONFIG_ALLCONFIG=custom-notebook.config make allnoconfig
or
KCONFIG_ALLCONFIG=mini.config make allnoconfig
or
make KCONFIG_ALLCONFIG=mini.config allnoconfig
These examples will disable most options (allnoconfig) but enable or
disable the options that are explicitly listed in the specified
mini-config files.
KCONFIG_NOSILENTUPDATE
--------------------------------------------------
If this variable has a non-blank value, it prevents silent kernel
config udpates (requires explicit updates).
KCONFIG_CONFIG
--------------------------------------------------
This environment variable can be used to specify a default kernel config
file name to override the default name of ".config".
KCONFIG_OVERWRITECONFIG
--------------------------------------------------
If you set KCONFIG_OVERWRITECONFIG in the environment, Kconfig will not
break symlinks when .config is a symlink to somewhere else.
KCONFIG_NOTIMESTAMP
--------------------------------------------------
If this environment variable exists and is non-null, the timestamp line
in generated .config files is omitted.
KCONFIG_AUTOCONFIG
--------------------------------------------------
This environment variable can be set to specify the path & name of the
"auto.conf" file. Its default value is "include/config/auto.conf".
KCONFIG_AUTOHEADER
--------------------------------------------------
This environment variable can be set to specify the path & name of the
"autoconf.h" (header) file. Its default value is "include/linux/autoconf.h".
______________________________________________________________________
menuconfig User Interface Options
----------------------------------------------------------------------
MENUCONFIG_MODE
--------------------------------------------------
This mode shows all sub-menus in one large tree.
Example:
MENUCONFIG_MODE=single_menu make menuconfig
======================================================================
xconfig
--------------------------------------------------
Searching in xconfig:
The Search function searches for kernel configuration symbol
names, so you have to know something close to what you are
looking for.
Example:
Ctrl-F hotplug
or
Menu: File, Search, hotplug
lists all config symbol entries that contain "hotplug" in
the symbol name. In this Search dialog, you may change the
config setting for any of the entries that are not grayed out.
You can also enter a different search string without having
to return to the main menu.
======================================================================
gconfig
--------------------------------------------------
Searching in gconfig:
None (gconfig isn't maintained as well as xconfig or menuconfig);
however, gconfig does have a few more viewing choices than
xconfig does.
###

14
Documentation/kbuild/makefiles.txt
View File

@ -383,6 +383,20 @@ more details, with real examples.
to prerequisites are referenced with $(src) (because they are not
generated files).
$(kecho)
echoing information to user in a rule is often a good practice
but when execution "make -s" one does not expect to see any output
except for warnings/errors.
To support this kbuild define $(kecho) which will echo out the
text following $(kecho) to stdout except if "make -s" is used.
Example:
#arch/blackfin/boot/Makefile
$(obj)/vmImage: $(obj)/vmlinux.gz
$(call if_changed,uimage)
@$(kecho) 'Kernel: $@ is ready'
--- 3.11 $(CC) support functions
The kernel may be built with several different versions of

4
Documentation/kbuild/modules.txt
View File

@ -253,7 +253,7 @@ following files:
# Module specific targets
genbin:
echo "X" > 8123_bin_shipped
echo "X" > 8123_bin.o_shipped
In example 2, we are down to two fairly simple files and for simple
@ -279,7 +279,7 @@ following files:
# Module specific targets
genbin:
echo "X" > 8123_bin_shipped
echo "X" > 8123_bin.o_shipped
endif

34
Documentation/kernel-doc-nano-HOWTO.txt
View File

@ -71,6 +71,11 @@ The @argument descriptions must begin on the very next line following
this opening short function description line, with no intervening
empty comment lines.
If a function parameter is "..." (varargs), it should be listed in
kernel-doc notation as:
* @...: description
Example kernel-doc data structure comment.
/**
@ -282,6 +287,32 @@ struct my_struct {
};
Including documentation blocks in source files
----------------------------------------------
To facilitate having source code and comments close together, you can
include kernel-doc documentation blocks that are free-form comments
instead of being kernel-doc for functions, structures, unions,
enums, or typedefs. This could be used for something like a
theory of operation for a driver or library code, for example.
This is done by using a DOC: section keyword with a section title. E.g.:
/**
* DOC: Theory of Operation
*
* The whizbang foobar is a dilly of a gizmo. It can do whatever you
* want it to do, at any time. It reads your mind. Here's how it works.
*
* foo bar splat
*
* The only drawback to this gizmo is that is can sometimes damage
* hardware, software, or its subject(s).
*/
DOC: sections are used in SGML templates files as indicated below.
How to make new SGML template files
-----------------------------------
@ -302,6 +333,9 @@ exported using EXPORT_SYMBOL.
!F<filename> <function [functions...]> is replaced by the
documentation, in <filename>, for the functions listed.
!P<filename> <section title> is replaced by the contents of the DOC:
section titled <section title> from <filename>.
Spaces are allowed in <section title>; do not quote the <section title>.
Tim.
*/ <twaugh@redhat.com>

178
Documentation/kernel-parameters.txt
View File

@ -89,7 +89,9 @@ parameter is applicable:
SPARC Sparc architecture is enabled.
SWSUSP Software suspend (hibernation) is enabled.
SUSPEND System suspend states are enabled.
FTRACE Function tracing enabled.
TS Appropriate touchscreen support is enabled.
UMS USB Mass Storage support is enabled.
USB USB support is enabled.
USBHID USB Human Interface Device support is enabled.
V4L Video For Linux support is enabled.
@ -139,6 +141,7 @@ and is between 256 and 4096 characters. It is defined in the file
ht -- run only enough ACPI to enable Hyper Threading
strict -- Be less tolerant of platforms that are not
strictly ACPI specification compliant.
rsdt -- prefer RSDT over (default) XSDT
See also Documentation/power/pm.txt, pci=noacpi
@ -149,16 +152,20 @@ and is between 256 and 4096 characters. It is defined in the file
default: 0
acpi_sleep= [HW,ACPI] Sleep options
Format: { s3_bios, s3_mode, s3_beep, s4_nohwsig, old_ordering }
See Documentation/power/video.txt for s3_bios and s3_mode.
Format: { s3_bios, s3_mode, s3_beep, s4_nohwsig,
old_ordering, s4_nonvs }
See Documentation/power/video.txt for information on
s3_bios and s3_mode.
s3_beep is for debugging; it makes the PC's speaker beep
as soon as the kernel's real-mode entry point is called.
s4_nohwsig prevents ACPI hardware signature from being
used during resume from hibernation.
old_ordering causes the ACPI 1.0 ordering of the _PTS
control method, wrt putting devices into low power
states, to be enforced (the ACPI 2.0 ordering of _PTS is
used by default).
control method, with respect to putting devices into
low power states, to be enforced (the ACPI 2.0 ordering
of _PTS is used by default).
s4_nonvs prevents the kernel from saving/restoring the
ACPI NVS memory during hibernation.
acpi_sci= [HW,ACPI] ACPI System Control Interrupt trigger mode
Format: { level | edge | high | low }
@ -193,7 +200,7 @@ and is between 256 and 4096 characters. It is defined in the file
acpi_skip_timer_override [HW,ACPI]
Recognize and ignore IRQ0/pin2 Interrupt Override.
For broken nForce2 BIOS resulting in XT-PIC timer.
acpi_use_timer_override [HW,ACPI}
acpi_use_timer_override [HW,ACPI]
Use timer override. For some broken Nvidia NF5 boards
that require a timer override, but don't have
HPET
@ -468,8 +475,8 @@ and is between 256 and 4096 characters. It is defined in the file
clearcpuid=BITNUM [X86]
Disable CPUID feature X for the kernel. See
include/asm-x86/cpufeature.h for the valid bit numbers.
Note the Linux specific bits are not necessarily
arch/x86/include/asm/cpufeature.h for the valid bit
numbers. Note the Linux specific bits are not necessarily
stable over kernel options, but the vendor specific
ones should be.
Also note that user programs calling CPUID directly
@ -550,6 +557,11 @@ and is between 256 and 4096 characters. It is defined in the file
not work reliably with all consoles, but is known
to work with serial and VGA consoles.
coredump_filter=
[KNL] Change the default value for
/proc/<pid>/coredump_filter.
See also Documentation/filesystems/proc.txt.
cpcihp_generic= [HW,PCI] Generic port I/O CompactPCI driver
Format:
<first_slot>,<last_slot>,<port>,<enum_bit>[,<debug>]
@ -753,6 +765,14 @@ and is between 256 and 4096 characters. It is defined in the file
parameter will force ia64_sal_cache_flush to call
ia64_pal_cache_flush instead of SAL_CACHE_FLUSH.
ftrace=[tracer]
[ftrace] will set and start the specified tracer
as early as possible in order to facilitate early
boot debugging.
ftrace_dump_on_oops
[ftrace] will dump the trace buffers on oops.
gamecon.map[2|3]=
[HW,JOY] Multisystem joystick and NES/SNES/PSX pad
support via parallel port (up to 5 devices per port)
@ -814,6 +834,9 @@ and is between 256 and 4096 characters. It is defined in the file
hlt [BUGS=ARM,SH]
hvc_iucv= [S390] Number of z/VM IUCV hypervisor console (HVC)
terminal devices. Valid values: 0..8
i8042.debug [HW] Toggle i8042 debug mode
i8042.direct [HW] Put keyboard port into non-translated mode
i8042.dumbkbd [HW] Pretend that controller can only read data from
@ -860,17 +883,19 @@ and is between 256 and 4096 characters. It is defined in the file
See Documentation/ide/ide.txt.
idle= [X86]
Format: idle=poll or idle=mwait, idle=halt, idle=nomwait
Poll forces a polling idle loop that can slightly improves the performance
of waking up a idle CPU, but will use a lot of power and make the system
run hot. Not recommended.
idle=mwait. On systems which support MONITOR/MWAIT but the kernel chose
to not use it because it doesn't save as much power as a normal idle
loop use the MONITOR/MWAIT idle loop anyways. Performance should be the same
as idle=poll.
idle=halt. Halt is forced to be used for CPU idle.
Format: idle=poll, idle=mwait, idle=halt, idle=nomwait
Poll forces a polling idle loop that can slightly
improve the performance of waking up a idle CPU, but
will use a lot of power and make the system run hot.
Not recommended.
idle=mwait: On systems which support MONITOR/MWAIT but
the kernel chose to not use it because it doesn't save
as much power as a normal idle loop, use the
MONITOR/MWAIT idle loop anyways. Performance should be
the same as idle=poll.
idle=halt: Halt is forced to be used for CPU idle.
In such case C2/C3 won't be used again.
idle=nomwait. Disable mwait for CPU C-states
idle=nomwait: Disable mwait for CPU C-states
ide-pci-generic.all-generic-ide [HW] (E)IDE subsystem
Claim all unknown PCI IDE storage controllers.
@ -901,6 +926,10 @@ and is between 256 and 4096 characters. It is defined in the file
inttest= [IA64]
iomem= Disable strict checking of access to MMIO memory
strict regions from userspace.
relaxed
iommu= [x86]
off
force
@ -1052,8 +1081,8 @@ and is between 256 and 4096 characters. It is defined in the file
lapic [X86-32,APIC] Enable the local APIC even if BIOS
disabled it.
lapic_timer_c2_ok [X86-32,x86-64,APIC] trust the local apic timer in
C2 power state.
lapic_timer_c2_ok [X86-32,x86-64,APIC] trust the local apic timer
in C2 power state.
libata.dma= [LIBATA] DMA control
libata.dma=0 Disable all PATA and SATA DMA
@ -1105,6 +1134,8 @@ and is between 256 and 4096 characters. It is defined in the file
If there are multiple matching configurations changing
the same attribute, the last one is used.
lmb=debug [KNL] Enable lmb debug messages.
load_ramdisk= [RAM] List of ramdisks to load from floppy
See Documentation/blockdev/ramdisk.txt.
@ -1396,7 +1427,20 @@ and is between 256 and 4096 characters. It is defined in the file
when a NMI is triggered.
Format: [state][,regs][,debounce][,die]
nmi_watchdog= [KNL,BUGS=X86-32] Debugging features for SMP kernels
nmi_watchdog= [KNL,BUGS=X86-32,X86-64] Debugging features for SMP kernels
Format: [panic,][num]
Valid num: 0,1,2
0 - turn nmi_watchdog off
1 - use the IO-APIC timer for the NMI watchdog
2 - use the local APIC for the NMI watchdog using
a performance counter. Note: This will use one performance
counter and the local APIC's performance vector.
When panic is specified panic when an NMI watchdog timeout occurs.
This is useful when you use a panic=... timeout and need the box
quickly up again.
Instead of 1 and 2 it is possible to use the following
symbolic names: lapic and ioapic
Example: nmi_watchdog=2 or nmi_watchdog=panic,lapic
no387 [BUGS=X86-32] Tells the kernel to use the 387 maths
emulation library even if a 387 maths coprocessor
@ -1452,6 +1496,10 @@ and is between 256 and 4096 characters. It is defined in the file
instruction doesn't work correctly and not to
use it.
no_file_caps Tells the kernel not to honor file capabilities. The
only way then for a file to be executed with privilege
is to be setuid root or executed by root.
nohalt [IA-64] Tells the kernel not to use the power saving
function PAL_HALT_LIGHT when idle. This increases
power-consumption. On the positive side, it reduces
@ -1521,6 +1569,9 @@ and is between 256 and 4096 characters. It is defined in the file
nosoftlockup [KNL] Disable the soft-lockup detector.
noswapaccount [KNL] Disable accounting of swap in memory resource
controller. (See Documentation/controllers/memory.txt)
nosync [HW,M68K] Disables sync negotiation for all devices.
notsc [BUGS=X86-32] Disable Time Stamp Counter
@ -1540,6 +1591,10 @@ and is between 256 and 4096 characters. It is defined in the file
nr_uarts= [SERIAL] maximum number of UARTs to be registered.
ohci1394_dma=early [HW] enable debugging via the ohci1394 driver.
See Documentation/debugging-via-ohci1394.txt for more
info.
olpc_ec_timeout= [OLPC] ms delay when issuing EC commands
Rather than timing out after 20 ms if an EC
command is not properly ACKed, override the length
@ -1629,6 +1684,17 @@ and is between 256 and 4096 characters. It is defined in the file
nomsi [MSI] If the PCI_MSI kernel config parameter is
enabled, this kernel boot option can be used to
disable the use of MSI interrupts system-wide.
noioapicquirk [APIC] Disable all boot interrupt quirks.
Safety option to keep boot IRQs enabled. This
should never be necessary.
ioapicreroute [APIC] Enable rerouting of boot IRQs to the
primary IO-APIC for bridges that cannot disable
boot IRQs. This fixes a source of spurious IRQs
when the system masks IRQs.
noioapicreroute [APIC] Disable workaround that uses the
boot IRQ equivalent of an IRQ that connects to
a chipset where boot IRQs cannot be disabled.
The opposite of ioapicreroute.
biosirq [X86-32] Use PCI BIOS calls to get the interrupt
routing table. These calls are known to be buggy
on several machines and they hang the machine
@ -1753,10 +1819,10 @@ and is between 256 and 4096 characters. It is defined in the file
autoconfiguration.
Ranges are in pairs (memory base and size).
dynamic_printk
Enables pr_debug()/dev_dbg() calls if
CONFIG_DYNAMIC_PRINTK_DEBUG has been enabled. These can also
be switched on/off via <debugfs>/dynamic_printk/modules
dynamic_printk Enables pr_debug()/dev_dbg() calls if
CONFIG_DYNAMIC_PRINTK_DEBUG has been enabled.
These can also be switched on/off via
<debugfs>/dynamic_printk/modules
print-fatal-signals=
[KNL] debug: print fatal signals
@ -1844,7 +1910,7 @@ and is between 256 and 4096 characters. It is defined in the file
reboot= [BUGS=X86-32,BUGS=ARM,BUGS=IA-64] Rebooting mode
Format: <reboot_mode>[,<reboot_mode2>[,...]]
See arch/*/kernel/reboot.c or arch/*/kernel/process.c
See arch/*/kernel/reboot.c or arch/*/kernel/process.c
relax_domain_level=
[KNL, SMP] Set scheduler's default relax_domain_level.
@ -2168,6 +2234,9 @@ and is between 256 and 4096 characters. It is defined in the file
st= [HW,SCSI] SCSI tape parameters (buffers, etc.)
See Documentation/scsi/st.txt.
stacktrace [FTRACE]
Enabled the stack tracer on boot up.
sti= [PARISC,HW]
Format: <num>
Set the STI (builtin display/keyboard on the HP-PARISC
@ -2241,7 +2310,8 @@ and is between 256 and 4096 characters. It is defined in the file
thermal.psv= [HW,ACPI]
-1: disable all passive trip points
<degrees C>: override all passive trip points to this value
<degrees C>: override all passive trip points to this
value
thermal.tzp= [HW,ACPI]
Specify global default ACPI thermal zone polling rate
@ -2252,12 +2322,27 @@ and is between 256 and 4096 characters. It is defined in the file
See comment before function dc390_setup() in
drivers/scsi/tmscsim.c.
topology= [S390]
Format: {off | on}
Specify if the kernel should make use of the cpu
topology informations if the hardware supports these.
The scheduler will make use of these informations and
e.g. base its process migration decisions on it.
Default is off.
tp720= [HW,PS2]
trix= [HW,OSS] MediaTrix AudioTrix Pro
Format:
<io>,<irq>,<dma>,<dma2>,<sb_io>,<sb_irq>,<sb_dma>,<mpu_io>,<mpu_irq>
tsc= Disable clocksource-must-verify flag for TSC.
Format: <string>
[x86] reliable: mark tsc clocksource as reliable, this
disables clocksource verification at runtime.
Used to enable high-resolution timer mode on older
hardware, and in virtualized environment.
turbografx.map[2|3]= [HW,JOY]
TurboGraFX parallel port interface
Format:
@ -2314,6 +2399,41 @@ and is between 256 and 4096 characters. It is defined in the file
usbhid.mousepoll=
[USBHID] The interval which mice are to be polled at.
usb-storage.delay_use=
[UMS] The delay in seconds before a new device is
scanned for Logical Units (default 5).
usb-storage.quirks=
[UMS] A list of quirks entries to supplement or
override the built-in unusual_devs list. List
entries are separated by commas. Each entry has
the form VID:PID:Flags where VID and PID are Vendor
and Product ID values (4-digit hex numbers) and
Flags is a set of characters, each corresponding
to a common usb-storage quirk flag as follows:
a = SANE_SENSE (collect more than 18 bytes
of sense data);
c = FIX_CAPACITY (decrease the reported
device capacity by one sector);
h = CAPACITY_HEURISTICS (decrease the
reported device capacity by one
sector if the number is odd);
i = IGNORE_DEVICE (don't bind to this
device);
l = NOT_LOCKABLE (don't try to lock and
unlock ejectable media);
m = MAX_SECTORS_64 (don't transfer more
than 64 sectors = 32 KB at a time);
o = CAPACITY_OK (accept the capacity
reported by the device);
r = IGNORE_RESIDUE (the device reports
bogus residue values);
s = SINGLE_LUN (the device has only one
Logical Unit);
w = NO_WP_DETECT (don't test whether the
medium is write-protected).
Example: quirks=0419:aaf5:rl,0421:0433:rc
add_efi_memmap [EFI; x86-32,X86-64] Include EFI memory map in
kernel's map of available physical RAM.
@ -2374,8 +2494,8 @@ and is between 256 and 4096 characters. It is defined in the file
Format:
<irq>,<irq_mask>,<io>,<full_duplex>,<do_sound>,<lockup_hack>[,<irq2>[,<irq3>[,<irq4>]]]
norandmaps Don't use address space randomization
Equivalent to echo 0 > /proc/sys/kernel/randomize_va_space
norandmaps Don't use address space randomization. Equivalent to
echo 0 > /proc/sys/kernel/randomize_va_space
______________________________________________________________________

4
Documentation/kobject.txt
View File

@ -118,8 +118,8 @@ the name of the kobject, call kobject_rename():
int kobject_rename(struct kobject *kobj, const char *new_name);
Note kobject_rename does perform any locking or have a solid notion of
what names are valid so the provide must provide their own sanity checking
kobject_rename does not perform any locking or have a solid notion of
what names are valid so the caller must provide their own sanity checking
and serialization.
There is a function called kobject_set_name() but that is legacy cruft and

5
Documentation/kprobes.txt
View File

@ -497,7 +497,10 @@ The first column provides the kernel address where the probe is inserted.
The second column identifies the type of probe (k - kprobe, r - kretprobe
and j - jprobe), while the third column specifies the symbol+offset of
the probe. If the probed function belongs to a module, the module name
is also specified.
is also specified. Following columns show probe status. If the probe is on
a virtual address that is no longer valid (module init sections, module
virtual addresses that correspond to modules that've been unloaded),
such probes are marked with [GONE].
/debug/kprobes/enabled: Turn kprobes ON/OFF

2
Documentation/laptops/thinkpad-acpi.txt
View File

@ -1475,7 +1475,7 @@ Sysfs interface changelog:
0x020100: Marker for thinkpad-acpi with hot key NVRAM polling
support. If you must, use it to know you should not
start an userspace NVRAM poller (allows to detect when
start a userspace NVRAM poller (allows to detect when
NVRAM is compiled out by the user because it is
unneeded/undesired in the first place).
0x020101: Marker for thinkpad-acpi with hot key NVRAM polling

66
Documentation/lguest/lguest.c
View File

@ -481,51 +481,6 @@ static unsigned long load_initrd(const char *name, unsigned long mem)
/* We return the initrd size. */
return len;
}
/* Once we know how much memory we have we can construct simple linear page
* tables which set virtual == physical which will get the Guest far enough
* into the boot to create its own.
*
* We lay them out of the way, just below the initrd (which is why we need to
* know its size here). */
static unsigned long setup_pagetables(unsigned long mem,
unsigned long initrd_size)
{
unsigned long *pgdir, *linear;
unsigned int mapped_pages, i, linear_pages;
unsigned int ptes_per_page = getpagesize()/sizeof(void *);
mapped_pages = mem/getpagesize();
/* Each PTE page can map ptes_per_page pages: how many do we need? */
linear_pages = (mapped_pages + ptes_per_page-1)/ptes_per_page;
/* We put the toplevel page directory page at the top of memory. */
pgdir = from_guest_phys(mem) - initrd_size - getpagesize();
/* Now we use the next linear_pages pages as pte pages */
linear = (void *)pgdir - linear_pages*getpagesize();
/* Linear mapping is easy: put every page's address into the mapping in
* order. PAGE_PRESENT contains the flags Present, Writable and
* Executable. */
for (i = 0; i < mapped_pages; i++)
linear[i] = ((i * getpagesize()) | PAGE_PRESENT);
/* The top level points to the linear page table pages above. */
for (i = 0; i < mapped_pages; i += ptes_per_page) {
pgdir[i/ptes_per_page]
= ((to_guest_phys(linear) + i*sizeof(void *))
| PAGE_PRESENT);
}
verbose("Linear mapping of %u pages in %u pte pages at %#lx\n",
mapped_pages, linear_pages, to_guest_phys(linear));
/* We return the top level (guest-physical) address: the kernel needs
* to know where it is. */
return to_guest_phys(pgdir);
}
/*:*/
/* Simple routine to roll all the commandline arguments together with spaces
@ -548,13 +503,13 @@ static void concat(char *dst, char *args[])
/*L:185 This is where we actually tell the kernel to initialize the Guest. We
* saw the arguments it expects when we looked at initialize() in lguest_user.c:
* the base of Guest "physical" memory, the top physical page to allow, the
* top level pagetable and the entry point for the Guest. */
static int tell_kernel(unsigned long pgdir, unsigned long start)
* the base of Guest "physical" memory, the top physical page to allow and the
* entry point for the Guest. */
static int tell_kernel(unsigned long start)
{
unsigned long args[] = { LHREQ_INITIALIZE,
(unsigned long)guest_base,
guest_limit / getpagesize(), pgdir, start };
guest_limit / getpagesize(), start };
int fd;
verbose("Guest: %p - %p (%#lx)\n",
@ -1030,7 +985,7 @@ static void update_device_status(struct device *dev)
/* Zero out the virtqueues. */
for (vq = dev->vq; vq; vq = vq->next) {
memset(vq->vring.desc, 0,
vring_size(vq->config.num, getpagesize()));
vring_size(vq->config.num, LGUEST_VRING_ALIGN));
lg_last_avail(vq) = 0;
}
} else if (dev->desc->status & VIRTIO_CONFIG_S_FAILED) {
@ -1211,7 +1166,7 @@ static void add_virtqueue(struct device *dev, unsigned int num_descs,
void *p;
/* First we need some memory for this virtqueue. */
pages = (vring_size(num_descs, getpagesize()) + getpagesize() - 1)
pages = (vring_size(num_descs, LGUEST_VRING_ALIGN) + getpagesize() - 1)
/ getpagesize();
p = get_pages(pages);
@ -1228,7 +1183,7 @@ static void add_virtqueue(struct device *dev, unsigned int num_descs,
vq->config.pfn = to_guest_phys(p) / getpagesize();
/* Initialize the vring. */
vring_init(&vq->vring, num_descs, p, getpagesize());
vring_init(&vq->vring, num_descs, p, LGUEST_VRING_ALIGN);
/* Append virtqueue to this device's descriptor. We use
* device_config() to get the end of the device's current virtqueues;
@ -1941,7 +1896,7 @@ int main(int argc, char *argv[])
{
/* Memory, top-level pagetable, code startpoint and size of the
* (optional) initrd. */
unsigned long mem = 0, pgdir, start, initrd_size = 0;
unsigned long mem = 0, start, initrd_size = 0;
/* Two temporaries and the /dev/lguest file descriptor. */
int i, c, lguest_fd;
/* The boot information for the Guest. */
@ -2040,9 +1995,6 @@ int main(int argc, char *argv[])
boot->hdr.type_of_loader = 0xFF;
}
/* Set up the initial linear pagetables, starting below the initrd. */
pgdir = setup_pagetables(mem, initrd_size);
/* The Linux boot header contains an "E820" memory map: ours is a
* simple, single region. */
boot->e820_entries = 1;
@ -2064,7 +2016,7 @@ int main(int argc, char *argv[])
/* We tell the kernel to initialize the Guest: this returns the open
* /dev/lguest file descriptor. */
lguest_fd = tell_kernel(pgdir, start);
lguest_fd = tell_kernel(start);
/* We clone off a thread, which wakes the Launcher whenever one of the
* input file descriptors needs attention. We call this the Waker, and

51
Documentation/lockstat.txt
View File

@ -71,35 +71,50 @@ Look at the current lock statistics:
# less /proc/lock_stat
01 lock_stat version 0.2
01 lock_stat version 0.3
02 -----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
03 class name con-bounces contentions waittime-min waittime-max waittime-total acq-bounces acquisitions holdtime-min holdtime-max holdtime-total
04 -----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
05
06 &inode->i_data.tree_lock-W: 15 21657 0.18 1093295.30 11547131054.85 58 10415 0.16 87.51 6387.60
07 &inode->i_data.tree_lock-R: 0 0 0.00 0.00 0.00 23302 231198 0.25 8.45 98023.38
08 --------------------------
09 &inode->i_data.tree_lock 0 [<ffffffff8027c08f>] add_to_page_cache+0x5f/0x190
10
11 ...............................................................................................................................................................................................
12
13 dcache_lock: 1037 1161 0.38 45.32 774.51 6611 243371 0.15 306.48 77387.24
14 -----------
15 dcache_lock 180 [<ffffffff802c0d7e>] sys_getcwd+0x11e/0x230
16 dcache_lock 165 [<ffffffff802c002a>] d_alloc+0x15a/0x210
17 dcache_lock 33 [<ffffffff8035818d>] _atomic_dec_and_lock+0x4d/0x70
18 dcache_lock 1 [<ffffffff802beef8>] shrink_dcache_parent+0x18/0x130
06 &mm->mmap_sem-W: 233 538 18446744073708 22924.27 607243.51 1342 45806 1.71 8595.89 1180582.34
07 &mm->mmap_sem-R: 205 587 18446744073708 28403.36 731975.00 1940 412426 0.58 187825.45 6307502.88
08 ---------------
09 &mm->mmap_sem 487 [<ffffffff8053491f>] do_page_fault+0x466/0x928
10 &mm->mmap_sem 179 [<ffffffff802a6200>] sys_mprotect+0xcd/0x21d
11 &mm->mmap_sem 279 [<ffffffff80210a57>] sys_mmap+0x75/0xce
12 &mm->mmap_sem 76 [<ffffffff802a490b>] sys_munmap+0x32/0x59
13 ---------------
14 &mm->mmap_sem 270 [<ffffffff80210a57>] sys_mmap+0x75/0xce
15 &mm->mmap_sem 431 [<ffffffff8053491f>] do_page_fault+0x466/0x928
16 &mm->mmap_sem 138 [<ffffffff802a490b>] sys_munmap+0x32/0x59
17 &mm->mmap_sem 145 [<ffffffff802a6200>] sys_mprotect+0xcd/0x21d
18
19 ...............................................................................................................................................................................................
20
21 dcache_lock: 621 623 0.52 118.26 1053.02 6745 91930 0.29 316.29 118423.41
22 -----------
23 dcache_lock 179 [<ffffffff80378274>] _atomic_dec_and_lock+0x34/0x54
24 dcache_lock 113 [<ffffffff802cc17b>] d_alloc+0x19a/0x1eb
25 dcache_lock 99 [<ffffffff802ca0dc>] d_rehash+0x1b/0x44
26 dcache_lock 104 [<ffffffff802cbca0>] d_instantiate+0x36/0x8a
27 -----------
28 dcache_lock 192 [<ffffffff80378274>] _atomic_dec_and_lock+0x34/0x54
29 dcache_lock 98 [<ffffffff802ca0dc>] d_rehash+0x1b/0x44
30 dcache_lock 72 [<ffffffff802cc17b>] d_alloc+0x19a/0x1eb
31 dcache_lock 112 [<ffffffff802cbca0>] d_instantiate+0x36/0x8a
This excerpt shows the first two lock class statistics. Line 01 shows the
output version - each time the format changes this will be updated. Line 02-04
show the header with column descriptions. Lines 05-10 and 13-18 show the actual
show the header with column descriptions. Lines 05-18 and 20-31 show the actual
statistics. These statistics come in two parts; the actual stats separated by a
short separator (line 08, 14) from the contention points.
short separator (line 08, 13) from the contention points.
The first lock (05-10) is a read/write lock, and shows two lines above the
The first lock (05-18) is a read/write lock, and shows two lines above the
short separator. The contention points don't match the column descriptors,
they have two: contentions and [<IP>] symbol.
they have two: contentions and [<IP>] symbol. The second set of contention
points are the points we're contending with.
The integer part of the time values is in us.
View the top contending locks:

6
Documentation/magic-number.txt
View File

@ -125,14 +125,14 @@ TRIDENT_CARD_MAGIC 0x5072696E trident_card sound/oss/trident.c
ROUTER_MAGIC 0x524d4157 wan_device include/linux/wanrouter.h
SCC_MAGIC 0x52696368 gs_port drivers/char/scc.h
SAVEKMSG_MAGIC1 0x53415645 savekmsg arch/*/amiga/config.c
GDA_MAGIC 0x58464552 gda include/asm-mips64/sn/gda.h
GDA_MAGIC 0x58464552 gda arch/mips/include/asm/sn/gda.h
RED_MAGIC1 0x5a2cf071 (any) mm/slab.c
STL_PORTMAGIC 0x5a7182c9 stlport include/linux/stallion.h
EEPROM_MAGIC_VALUE 0x5ab478d2 lanai_dev drivers/atm/lanai.c
HDLCDRV_MAGIC 0x5ac6e778 hdlcdrv_state include/linux/hdlcdrv.h
EPCA_MAGIC 0x5c6df104 channel include/linux/epca.h
PCXX_MAGIC 0x5c6df104 channel drivers/char/pcxx.h
KV_MAGIC 0x5f4b565f kernel_vars_s include/asm-mips64/sn/klkernvars.h
KV_MAGIC 0x5f4b565f kernel_vars_s arch/mips/include/asm/sn/klkernvars.h
I810_STATE_MAGIC 0x63657373 i810_state sound/oss/i810_audio.c
TRIDENT_STATE_MAGIC 0x63657373 trient_state sound/oss/trident.c
M3_CARD_MAGIC 0x646e6f50 m3_card sound/oss/maestro3.c
@ -158,7 +158,7 @@ CCB_MAGIC 0xf2691ad2 ccb drivers/scsi/ncr53c8xx.c
QUEUE_MAGIC_FREE 0xf7e1c9a3 queue_entry drivers/scsi/arm/queue.c
QUEUE_MAGIC_USED 0xf7e1cc33 queue_entry drivers/scsi/arm/queue.c
HTB_CMAGIC 0xFEFAFEF1 htb_class net/sched/sch_htb.c
NMI_MAGIC 0x48414d4d455201 nmi_s include/asm-mips64/sn/nmi.h
NMI_MAGIC 0x48414d4d455201 nmi_s arch/mips/include/asm/sn/nmi.h
Note that there are also defined special per-driver magic numbers in sound
memory management. See include/sound/sndmagic.h for complete list of them. Many

29
Documentation/markers.txt
View File

@ -51,11 +51,16 @@ to call) for the specific marker through marker_probe_register() and can be
activated by calling marker_arm(). Marker deactivation can be done by calling
marker_disarm() as many times as marker_arm() has been called. Removing a probe
is done through marker_probe_unregister(); it will disarm the probe.
marker_synchronize_unregister() must be called before the end of the module exit
function to make sure there is no caller left using the probe. This, and the
fact that preemption is disabled around the probe call, make sure that probe
removal and module unload are safe. See the "Probe example" section below for a
sample probe module.
marker_synchronize_unregister() must be called between probe unregistration and
the first occurrence of
- the end of module exit function,
to make sure there is no caller left using the probe;
- the free of any resource used by the probes,
to make sure the probes wont be accessing invalid data.
This, and the fact that preemption is disabled around the probe call, make sure
that probe removal and module unload are safe. See the "Probe example" section
below for a sample probe module.
The marker mechanism supports inserting multiple instances of the same marker.
Markers can be put in inline functions, inlined static functions, and
@ -70,6 +75,20 @@ a printk warning which identifies the inconsistency:
"Format mismatch for probe probe_name (format), marker (format)"
Another way to use markers is to simply define the marker without generating any
function call to actually call into the marker. This is useful in combination
with tracepoint probes in a scheme like this :
void probe_tracepoint_name(unsigned int arg1, struct task_struct *tsk);
DEFINE_MARKER_TP(marker_eventname, tracepoint_name, probe_tracepoint_name,
"arg1 %u pid %d");
notrace void probe_tracepoint_name(unsigned int arg1, struct task_struct *tsk)
{
struct marker *marker = &GET_MARKER(kernel_irq_entry);
/* write data to trace buffers ... */
}
* Probe / marker example

16
Documentation/memory-hotplug.txt
View File

@ -124,7 +124,7 @@ config options.
This option can be kernel module too.
--------------------------------
3 sysfs files for memory hotplug
4 sysfs files for memory hotplug
--------------------------------
All sections have their device information under /sys/devices/system/memory as
@ -138,11 +138,12 @@ For example, assume 1GiB section size. A device for a memory starting at
(0x100000000 / 1Gib = 4)
This device covers address range [0x100000000 ... 0x140000000)
Under each section, you can see 3 files.
Under each section, you can see 4 files.
/sys/devices/system/memory/memoryXXX/phys_index
/sys/devices/system/memory/memoryXXX/phys_device
/sys/devices/system/memory/memoryXXX/state
/sys/devices/system/memory/memoryXXX/removable
'phys_index' : read-only and contains section id, same as XXX.
'state' : read-write
@ -150,10 +151,20 @@ Under each section, you can see 3 files.
at write: user can specify "online", "offline" command
'phys_device': read-only: designed to show the name of physical memory device.
This is not well implemented now.
'removable' : read-only: contains an integer value indicating
whether the memory section is removable or not
removable. A value of 1 indicates that the memory
section is removable and a value of 0 indicates that
it is not removable.
NOTE:
These directories/files appear after physical memory hotplug phase.
If CONFIG_NUMA is enabled the
/sys/devices/system/memory/memoryXXX memory section
directories can also be accessed via symbolic links located in
the /sys/devices/system/node/node* directories. For example:
/sys/devices/system/node/node0/memory9 -> ../../memory/memory9
--------------------------------
4. Physical memory hot-add phase
@ -365,7 +376,6 @@ node if necessary.
- allowing memory hot-add to ZONE_MOVABLE. maybe we need some switch like
sysctl or new control file.
- showing memory section and physical device relationship.
- showing memory section and node relationship (maybe good for NUMA)
- showing memory section is under ZONE_MOVABLE or not
- test and make it better memory offlining.
- support HugeTLB page migration and offlining.

8
Documentation/mips/AU1xxx_IDE.README
View File

@ -44,7 +44,7 @@ FILES, CONFIGS AND COMPATABILITY
Two files are introduced:
a) 'include/asm-mips/mach-au1x00/au1xxx_ide.h'
a) 'arch/mips/include/asm/mach-au1x00/au1xxx_ide.h'
containes : struct _auide_hwif
timing parameters for PIO mode 0/1/2/3/4
timing parameters for MWDMA 0/1/2
@ -52,14 +52,12 @@ Two files are introduced:
b) 'drivers/ide/mips/au1xxx-ide.c'
contains the functionality of the AU1XXX IDE driver
Four configs variables are introduced:
Following extra configs variables are introduced:
CONFIG_BLK_DEV_IDE_AU1XXX_PIO_DBDMA - enable the PIO+DBDMA mode
CONFIG_BLK_DEV_IDE_AU1XXX_MDMA2_DBDMA - enable the MWDMA mode
CONFIG_BLK_DEV_IDE_AU1XXX_BURSTABLE_ON - set Burstable FIFO in DBDMA
controller
CONFIG_BLK_DEV_IDE_AU1XXX_SEQTS_PER_RQ - maximum transfer size
per descriptor
SUPPORTED IDE MODES
@ -87,7 +85,6 @@ CONFIG_BLK_DEV_IDEDMA_PCI=y
CONFIG_IDEDMA_PCI_AUTO=y
CONFIG_BLK_DEV_IDE_AU1XXX=y
CONFIG_BLK_DEV_IDE_AU1XXX_MDMA2_DBDMA=y
CONFIG_BLK_DEV_IDE_AU1XXX_SEQTS_PER_RQ=128
CONFIG_BLK_DEV_IDEDMA=y
CONFIG_IDEDMA_AUTO=y
@ -105,7 +102,6 @@ CONFIG_BLK_DEV_IDEDMA_PCI=y
CONFIG_IDEDMA_PCI_AUTO=y
CONFIG_BLK_DEV_IDE_AU1XXX=y
CONFIG_BLK_DEV_IDE_AU1XXX_MDMA2_DBDMA=y
CONFIG_BLK_DEV_IDE_AU1XXX_SEQTS_PER_RQ=128
CONFIG_BLK_DEV_IDEDMA=y
CONFIG_IDEDMA_AUTO=y

2
Documentation/networking/README.ipw2200
View File

@ -147,7 +147,7 @@ Where the supported parameter are:
driver. If disabled, the driver will not attempt to scan
for and associate to a network until it has been configured with
one or more properties for the target network, for example configuring
the network SSID. Default is 1 (auto-associate)
the network SSID. Default is 0 (do not auto-associate)
Example: % modprobe ipw2200 associate=0

68
Documentation/networking/bonding.txt
View File

@ -194,6 +194,48 @@ or, for backwards compatibility, the option value. E.g.,
The parameters are as follows:
ad_select
Specifies the 802.3ad aggregation selection logic to use. The
possible values and their effects are:
stable or 0
The active aggregator is chosen by largest aggregate
bandwidth.
Reselection of the active aggregator occurs only when all
slaves of the active aggregator are down or the active
aggregator has no slaves.
This is the default value.
bandwidth or 1
The active aggregator is chosen by largest aggregate
bandwidth. Reselection occurs if:
- A slave is added to or removed from the bond
- Any slave's link state changes
- Any slave's 802.3ad association state changes
- The bond's adminstrative state changes to up
count or 2
The active aggregator is chosen by the largest number of
ports (slaves). Reselection occurs as described under the
"bandwidth" setting, above.
The bandwidth and count selection policies permit failover of
802.3ad aggregations when partial failure of the active aggregator
occurs. This keeps the aggregator with the highest availability
(either in bandwidth or in number of ports) active at all times.
This option was added in bonding version 3.4.0.
arp_interval
Specifies the ARP link monitoring frequency in milliseconds.
@ -551,6 +593,16 @@ num_grat_arp
affects only the active-backup mode. This option was added for
bonding version 3.3.0.
num_unsol_na
Specifies the number of unsolicited IPv6 Neighbor Advertisements
to be issued after a failover event. One unsolicited NA is issued
immediately after the failover.
The valid range is 0 - 255; the default value is 1. This option
affects only the active-backup mode. This option was added for
bonding version 3.4.0.
primary
A string (eth0, eth2, etc) specifying which slave is the
@ -922,17 +974,19 @@ USERCTL=no
NETMASK, NETWORK and BROADCAST) to match your network configuration.
For later versions of initscripts, such as that found with Fedora
7 and Red Hat Enterprise Linux version 5 (or later), it is possible, and,
indeed, preferable, to specify the bonding options in the ifcfg-bond0
7 (or later) and Red Hat Enterprise Linux version 5 (or later), it is possible,
and, indeed, preferable, to specify the bonding options in the ifcfg-bond0
file, e.g. a line of the format:
BONDING_OPTS="mode=active-backup arp_interval=60 arp_ip_target=+192.168.1.254"
BONDING_OPTS="mode=active-backup arp_interval=60 arp_ip_target=192.168.1.254"
will configure the bond with the specified options. The options
specified in BONDING_OPTS are identical to the bonding module parameters
except for the arp_ip_target field. Each target should be included as a
separate option and should be preceded by a '+' to indicate it should be
added to the list of queried targets, e.g.,
except for the arp_ip_target field when using versions of initscripts older
than and 8.57 (Fedora 8) and 8.45.19 (Red Hat Enterprise Linux 5.2). When
using older versions each target should be included as a separate option and
should be preceded by a '+' to indicate it should be added to the list of
queried targets, e.g.,
arp_ip_target=+192.168.1.1 arp_ip_target=+192.168.1.2
@ -940,7 +994,7 @@ added to the list of queried targets, e.g.,
options via BONDING_OPTS, it is not necessary to edit /etc/modules.conf or
/etc/modprobe.conf.
For older versions of initscripts that do not support
For even older versions of initscripts that do not support
BONDING_OPTS, it is necessary to edit /etc/modules.conf (or
/etc/modprobe.conf, depending upon your distro) to load the bonding module
with your desired options when the bond0 interface is brought up. The

32
Documentation/networking/dccp.txt
View File

@ -57,6 +57,24 @@ can be set before calling bind().
DCCP_SOCKOPT_GET_CUR_MPS is read-only and retrieves the current maximum packet
size (application payload size) in bytes, see RFC 4340, section 14.
DCCP_SOCKOPT_AVAILABLE_CCIDS is also read-only and returns the list of CCIDs
supported by the endpoint (see include/linux/dccp.h for symbolic constants).
The caller needs to provide a sufficiently large (> 2) array of type uint8_t.
DCCP_SOCKOPT_CCID is write-only and sets both the TX and RX CCIDs at the same
time, combining the operation of the next two socket options. This option is
preferrable over the latter two, since often applications will use the same
type of CCID for both directions; and mixed use of CCIDs is not currently well
understood. This socket option takes as argument at least one uint8_t value, or
an array of uint8_t values, which must match available CCIDS (see above). CCIDs
must be registered on the socket before calling connect() or listen().
DCCP_SOCKOPT_TX_CCID is read/write. It returns the current CCID (if set) or sets
the preference list for the TX CCID, using the same format as DCCP_SOCKOPT_CCID.
Please note that the getsockopt argument type here is `int', not uint8_t.
DCCP_SOCKOPT_RX_CCID is analogous to DCCP_SOCKOPT_TX_CCID, but for the RX CCID.
DCCP_SOCKOPT_SERVER_TIMEWAIT enables the server (listening socket) to hold
timewait state when closing the connection (RFC 4340, 8.3). The usual case is
that the closing server sends a CloseReq, whereupon the client holds timewait
@ -115,20 +133,12 @@ retries2
importance for retransmitted acknowledgments and feature negotiation,
data packets are never retransmitted. Analogue of tcp_retries2.
send_ndp = 1
Whether or not to send NDP count options (sec. 7.7.2).
send_ackvec = 1
Whether or not to send Ack Vector options (sec. 11.5).
ack_ratio = 2
The default Ack Ratio (sec. 11.3) to use.
tx_ccid = 2
Default CCID for the sender-receiver half-connection.
Default CCID for the sender-receiver half-connection. Depending on the
choice of CCID, the Send Ack Vector feature is enabled automatically.
rx_ccid = 2
Default CCID for the receiver-sender half-connection.
Default CCID for the receiver-sender half-connection; see tx_ccid.
seq_window = 100
The initial sequence window (sec. 7.5.2).

2
Documentation/networking/driver.txt
View File

@ -13,7 +13,7 @@ Transmit path guidelines:
static int drv_hard_start_xmit(struct sk_buff *skb,
struct net_device *dev)
{
struct drv *dp = dev->priv;
struct drv *dp = netdev_priv(dev);
lock_tx(dp);
...

8
Documentation/networking/generic-hdlc.txt
View File

@ -3,15 +3,15 @@ Krzysztof Halasa <khc@pm.waw.pl>
Generic HDLC layer currently supports:
1. Frame Relay (ANSI, CCITT, Cisco and no LMI).
1. Frame Relay (ANSI, CCITT, Cisco and no LMI)
- Normal (routed) and Ethernet-bridged (Ethernet device emulation)
interfaces can share a single PVC.
- ARP support (no InARP support in the kernel - there is an
experimental InARP user-space daemon available on:
http://www.kernel.org/pub/linux/utils/net/hdlc/).
2. raw HDLC - either IP (IPv4) interface or Ethernet device emulation.
3. Cisco HDLC.
4. PPP (uses syncppp.c).
2. raw HDLC - either IP (IPv4) interface or Ethernet device emulation
3. Cisco HDLC
4. PPP
5. X.25 (uses X.25 routines).
Generic HDLC is a protocol driver only - it needs a low-level driver

6
Documentation/networking/ip-sysctl.txt
View File

@ -27,6 +27,12 @@ min_adv_mss - INTEGER
The advertised MSS depends on the first hop route MTU, but will
never be lower than this setting.
rt_cache_rebuild_count - INTEGER
The per net-namespace route cache emergency rebuild threshold.
Any net-namespace having its route cache rebuilt due to
a hash bucket chain being too long more than this many times
will have its route caching disabled
IP Fragmentation:
ipfrag_high_thresh - INTEGER

9
Documentation/networking/mac80211_hwsim/README
View File

@ -50,10 +50,6 @@ associates with the AP. hostapd and wpa_supplicant are used to take
care of WPA2-PSK authentication. In addition, hostapd is also
processing access point side of association.
Please note that the current Linux kernel does not enable AP mode, so a
simple patch is needed to enable AP mode selection:
http://johannes.sipsolutions.net/patches/kernel/all/LATEST/006-allow-ap-vlan-modes.patch
# Build mac80211_hwsim as part of kernel configuration
@ -65,3 +61,8 @@ hostapd hostapd.conf
# Run wpa_supplicant (station) for wlan1
wpa_supplicant -Dwext -iwlan1 -c wpa_supplicant.conf
More test cases are available in hostap.git:
git://w1.fi/srv/git/hostap.git and mac80211_hwsim/tests subdirectory
(http://w1.fi/gitweb/gitweb.cgi?p=hostap.git;a=tree;f=mac80211_hwsim/tests)

2
Documentation/networking/netdevices.txt
View File

@ -18,7 +18,7 @@ There are routines in net_init.c to handle the common cases of
alloc_etherdev, alloc_netdev. These reserve extra space for driver
private data which gets freed when the network device is freed. If
separately allocated data is attached to the network device
(dev->priv) then it is up to the module exit handler to free that.
(netdev_priv(dev)) then it is up to the module exit handler to free that.
MTU
===

22
Documentation/networking/regulatory.txt
View File

@ -131,11 +131,13 @@ are expected to do this during initialization.
r = zd_reg2alpha2(mac->regdomain, alpha2);
if (!r)
regulatory_hint(hw->wiphy, alpha2, NULL);
regulatory_hint(hw->wiphy, alpha2);
Example code - drivers providing a built in regulatory domain:
--------------------------------------------------------------
[NOTE: This API is not currently available, it can be added when required]
If you have regulatory information you can obtain from your
driver and you *need* to use this we let you build a regulatory domain
structure and pass it to the wireless core. To do this you should
@ -167,7 +169,6 @@ struct ieee80211_regdomain mydriver_jp_regdom = {
Then in some part of your code after your wiphy has been registered:
int r;
struct ieee80211_regdomain *rd;
int size_of_regd;
int num_rules = mydriver_jp_regdom.n_reg_rules;
@ -178,17 +179,12 @@ Then in some part of your code after your wiphy has been registered:
rd = kzalloc(size_of_regd, GFP_KERNEL);
if (!rd)
return -ENOMEM;
return -ENOMEM;
memcpy(rd, &mydriver_jp_regdom, sizeof(struct ieee80211_regdomain));
for (i=0; i < num_rules; i++) {
memcpy(&rd->reg_rules[i], &mydriver_jp_regdom.reg_rules[i],
sizeof(struct ieee80211_reg_rule));
}
r = regulatory_hint(hw->wiphy, NULL, rd);
if (r) {
kfree(rd);
return r;
}
for (i=0; i < num_rules; i++)
memcpy(&rd->reg_rules[i],
&mydriver_jp_regdom.reg_rules[i],
sizeof(struct ieee80211_reg_rule));
regulatory_struct_hint(rd);

2
Documentation/networking/rxrpc.txt
View File

@ -540,7 +540,7 @@ A client would issue an operation by:
MSG_MORE should be set in msghdr::msg_flags on all but the last part of
the request. Multiple requests may be made simultaneously.
If a call is intended to go to a destination other then the default
If a call is intended to go to a destination other than the default
specified through connect(), then msghdr::msg_name should be set on the
first request message of that call.

2
Documentation/networking/tuntap.txt
View File

@ -118,7 +118,7 @@ As mentioned above, main purpose of TUN/TAP driver is tunneling.
It is used by VTun (http://vtun.sourceforge.net).
Another interesting application using TUN/TAP is pipsecd
(http://perso.enst.fr/~beyssac/pipsec/), an userspace IPSec
(http://perso.enst.fr/~beyssac/pipsec/), a userspace IPSec
implementation that can use complete kernel routing (unlike FreeS/WAN).
3. How does Virtual network device actually work ?

5
Documentation/nmi_watchdog.txt
View File

@ -69,6 +69,11 @@ to the overall system performance.
On x86 nmi_watchdog is disabled by default so you have to enable it with
a boot time parameter.
It's possible to disable the NMI watchdog in run-time by writing "0" to
/proc/sys/kernel/nmi_watchdog. Writing "1" to the same file will re-enable
the NMI watchdog. Notice that you still need to use "nmi_watchdog=" parameter
at boot time.
NOTE: In kernels prior to 2.4.2-ac18 the NMI-oopser is enabled unconditionally
on x86 SMP boxes.

31
Documentation/nommu-mmap.txt
View File

@ -109,12 +109,18 @@ and it's also much more restricted in the latter case:
FURTHER NOTES ON NO-MMU MMAP
============================
(*) A request for a private mapping of less than a page in size may not return
a page-aligned buffer. This is because the kernel calls kmalloc() to
allocate the buffer, not get_free_page().
(*) A request for a private mapping of a file may return a buffer that is not
page-aligned. This is because XIP may take place, and the data may not be
paged aligned in the backing store.
(*) A list of all the mappings on the system is visible through /proc/maps in
no-MMU mode.
(*) A request for an anonymous mapping will always be page aligned. If
possible the size of the request should be a power of two otherwise some
of the space may be wasted as the kernel must allocate a power-of-2
granule but will only discard the excess if appropriately configured as
this has an effect on fragmentation.
(*) A list of all the private copy and anonymous mappings on the system is
visible through /proc/maps in no-MMU mode.
(*) A list of all the mappings in use by a process is visible through
/proc/<pid>/maps in no-MMU mode.
@ -242,3 +248,18 @@ PROVIDING SHAREABLE BLOCK DEVICE SUPPORT
Provision of shared mappings on block device files is exactly the same as for
character devices. If there isn't a real device underneath, then the driver
should allocate sufficient contiguous memory to honour any supported mapping.
=================================
ADJUSTING PAGE TRIMMING BEHAVIOUR
=================================
NOMMU mmap automatically rounds up to the nearest power-of-2 number of pages
when performing an allocation. This can have adverse effects on memory
fragmentation, and as such, is left configurable. The default behaviour is to
aggressively trim allocations and discard any excess pages back in to the page
allocator. In order to retain finer-grained control over fragmentation, this
behaviour can either be disabled completely, or bumped up to a higher page
watermark where trimming begins.
Page trimming behaviour is configurable via the sysctl `vm.nr_trim_pages'.

2
Documentation/powerpc/cpu_features.txt
View File

@ -31,7 +31,7 @@ anyways).
After detecting the processor type, the kernel patches out sections of code
that shouldn't be used by writing nop's over it. Using cpufeatures requires
just 2 macros (found in include/asm-ppc/cputable.h), as seen in head.S
just 2 macros (found in arch/powerpc/include/asm/cputable.h), as seen in head.S
transfer_to_handler:
#ifdef CONFIG_ALTIVEC

39
Documentation/powerpc/dts-bindings/4xx/ndfc.txt Normal file
View File

@ -0,0 +1,39 @@
AMCC NDFC (NanD Flash Controller)
Required properties:
- compatible : "ibm,ndfc".
- reg : should specify chip select and size used for the chip (0x2000).
Optional properties:
- ccr : NDFC config and control register value (default 0).
- bank-settings : NDFC bank configuration register value (default 0).
Notes:
- partition(s) - follows the OF MTD standard for partitions
Example:
ndfc@1,0 {
compatible = "ibm,ndfc";
reg = <0x00000001 0x00000000 0x00002000>;
ccr = <0x00001000>;
bank-settings = <0x80002222>;
#address-cells = <1>;
#size-cells = <1>;
nand {
#address-cells = <1>;
#size-cells = <1>;
partition@0 {
label = "kernel";
reg = <0x00000000 0x00200000>;
};
partition@200000 {
label = "root";
reg = <0x00200000 0x03E00000>;
};
};
};

32
Documentation/powerpc/dts-bindings/fsl/board.txt
View File

@ -18,7 +18,7 @@ This is the memory-mapped registers for on board FPGA.
Required properities:
- compatible : should be "fsl,fpga-pixis".
- reg : should contain the address and the lenght of the FPPGA register
- reg : should contain the address and the length of the FPPGA register
set.
Example (MPC8610HPCD):
@ -27,3 +27,33 @@ Example (MPC8610HPCD):
compatible = "fsl,fpga-pixis";
reg = <0xe8000000 32>;
};
* Freescale BCSR GPIO banks
Some BCSR registers act as simple GPIO controllers, each such
register can be represented by the gpio-controller node.
Required properities:
- compatible : Should be "fsl,<board>-bcsr-gpio".
- reg : Should contain the address and the length of the GPIO bank
register.
- #gpio-cells : Should be two. The first cell is the pin number and the
second cell is used to specify optional paramters (currently unused).
- gpio-controller : Marks the port as GPIO controller.
Example:
bcsr@1,0 {
#address-cells = <1>;
#size-cells = <1>;
compatible = "fsl,mpc8360mds-bcsr";
reg = <1 0 0x8000>;
ranges = <0 1 0 0x8000>;
bcsr13: gpio-controller@d {
#gpio-cells = <2>;
compatible = "fsl,mpc8360mds-bcsr-gpio";
reg = <0xd 1>;
gpio-controller;
};
};

12
Documentation/powerpc/dts-bindings/fsl/tsec.txt
View File

@ -2,8 +2,8 @@
The MDIO is a bus to which the PHY devices are connected. For each
device that exists on this bus, a child node should be created. See
the definition of the PHY node below for an example of how to define
a PHY.
the definition of the PHY node in booting-without-of.txt for an example
of how to define a PHY.
Required properties:
- reg : Offset and length of the register set for the device
@ -21,6 +21,14 @@ Example:
};
};
* TBI Internal MDIO bus
As of this writing, every tsec is associated with an internal TBI PHY.
This PHY is accessed through the local MDIO bus. These buses are defined
similarly to the mdio buses, except they are compatible with "fsl,gianfar-tbi".
The TBI PHYs underneath them are similar to normal PHYs, but the reg property
is considered instructive, rather than descriptive. The reg property should
be chosen so it doesn't interfere with other PHYs on the bus.
* Gianfar-compatible ethernet nodes

20
Documentation/rfkill.txt
View File

@ -191,12 +191,20 @@ Userspace input handlers (uevents) or kernel input handlers (rfkill-input):
to tell the devices registered with the rfkill class to change
their state (i.e. translates the input layer event into real
action).
* rfkill-input implements EPO by handling EV_SW SW_RFKILL_ALL 0
(power off all transmitters) in a special way: it ignores any
overrides and local state cache and forces all transmitters to the
RFKILL_STATE_SOFT_BLOCKED state (including those which are already
supposed to be BLOCKED). Note that the opposite event (power on all
transmitters) is handled normally.
supposed to be BLOCKED).
* rfkill EPO will remain active until rfkill-input receives an
EV_SW SW_RFKILL_ALL 1 event. While the EPO is active, transmitters
are locked in the blocked state (rfkill will refuse to unblock them).
* rfkill-input implements different policies that the user can
select for handling EV_SW SW_RFKILL_ALL 1. It will unlock rfkill,
and either do nothing (leave transmitters blocked, but now unlocked),
restore the transmitters to their state before the EPO, or unblock
them all.
Userspace uevent handler or kernel platform-specific drivers hooked to the
rfkill notifier chain:
@ -331,11 +339,9 @@ class to get a sysfs interface :-)
correct event for your switch/button. These events are emergency power-off
events when they are trying to turn the transmitters off. An example of an
input device which SHOULD generate *_RFKILL_ALL events is the wireless-kill
switch in a laptop which is NOT a hotkey, but a real switch that kills radios
in hardware, even if the O.S. has gone to lunch. An example of an input device
which SHOULD NOT generate *_RFKILL_ALL events by default, is any sort of hot
key that does nothing by itself, as well as any hot key that is type-specific
(e.g. the one for WLAN).
switch in a laptop which is NOT a hotkey, but a real sliding/rocker switch.
An example of an input device which SHOULD NOT generate *_RFKILL_ALL events by
default, is any sort of hot key that is type-specific (e.g. the one for WLAN).
3.1 Guidelines for wireless device drivers

2
Documentation/s390/Debugging390.txt
View File

@ -1402,7 +1402,7 @@ Syscalls are implemented on Linux for S390 by the Supervisor call instruction (S
possibilities of these as the instruction is made up of a 0xA opcode & the second byte being
the syscall number. They are traced using the simple command.
TR SVC <Optional value or range>
the syscalls are defined in linux/include/asm-s390/unistd.h
the syscalls are defined in linux/arch/s390/include/asm/unistd.h
e.g. to trace all file opens just do
TR SVC 5 ( as this is the syscall number of open )

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