android/android_kernel_xiaomi_sm8450
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

x86 setup: set %ebx == %ebp == %edi == 0 on protected mode entry

Browse Source 
In accordance with the newly formalized 32-bit boot protocol, set
%ebx == %ebp == %edi == 0 in order to support future extensions to the
protocol.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>
This commit is contained in:
H. Peter Anvin 2007-11-04 17:54:31 -08:00
parent 7ed192906a
commit 9f259cc59b
1 changed files with 3 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
arch/x86/boot/pmjump.S
View File

@ -28,11 +28,13 @@
* void protected_mode_jump(u32 entrypoint, u32 bootparams); * void protected_mode_jump(u32 entrypoint, u32 bootparams);
*/ */
protected_mode_jump: protected_mode_jump:
xorl %ebx, %ebx # Flag to indicate this is a boot
movl %edx, %esi # Pointer to boot_params table movl %edx, %esi # Pointer to boot_params table
movl %eax, 2f # Patch ljmpl instruction movl %eax, 2f # Patch ljmpl instruction
movw $__BOOT_DS, %cx movw $__BOOT_DS, %cx
xorl %ebx, %ebx # Per the 32-bit boot protocol
xorl %ebp, %ebp # Per the 32-bit boot protocol
xorl %edi, %edi # Per the 32-bit boot protocol
movl %cr0, %edx movl %cr0, %edx
orb $1, %dl # Protected mode (PE) bit orb $1, %dl # Protected mode (PE) bit