6 Commits

Author SHA1 Message Date
4712c1b203 bpf, doc: add basic README.rst file
A README.rst file in a directory have special meaning for sites like
github, which auto renders the contents.  Plus search engines like
Google also index these README.rst files.

Auto rendering allow us to use links, for (re)directing eBPF users to
other places where docs live.  The end-goal would be to direct users
towards https://www.kernel.org/doc/html/latest but we haven't written
the full docs yet, so we start out small and take this incrementally.

This directory itself contains some useful docs, which can be linked
to from the README.rst file (verified this works for github).

Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2018-05-14 23:02:58 -07:00
514d6c1959 bpf: Document sockmap '-target bpf' requirement for PROG_TYPE_SK_MSG
BPF_PROG_TYPE_SK_MSG programs use a 'void *' for both data and the
data_end pointers. Additionally, the verifier ensures that every
accesses into the values is a __u64 read. This correctly maps on
to the BPF 64-bit architecture.

However, to ensure that when building on 32bit architectures that
clang uses correct types the '-target bpf' option _must_ be
specified. To make this clear add a note to the Documentation.

Signed-off-by: John Fastabend <john.fastabend@gmail.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2018-04-23 23:42:21 +02:00
78262f4575 bpf, doc: add description wrt native/bpf clang target and pointer size
As this recently came up on netdev [0], lets add it to the BPF devel doc.

  [0] https://www.spinics.net/lists/netdev/msg489612.html

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2018-03-20 15:47:45 -07:00
6215ea6b7e bpf: add documentation to compare clang "-target bpf" and default target
The added documentation explains how generated codes may differ
between clang bpf target and default target, and when to use
each target.

Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2018-02-02 11:14:19 +01:00
34f15bf31e bpf, doc: add faq about bpf development process
In the same spirit of netdev FAQ, start a BPF FAQ as a collection
of expectations and/or workflow details in the context of BPF patch
processing.

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2017-12-06 14:32:42 -08:00
2e39748a42 bpf: document answers to common questions about BPF
to address common misconceptions about what BPF is and what it's not
add short BPF Q&A that clarifies core BPF design principles and
answers some common questions.

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Acked-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-11-01 21:01:47 +09:00