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| author | Tian Kevin <kevin.tian@intel.com> | 2007-06-24 04:16:52 +0400 |
|---|---|---|
| committer | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2007-06-24 19:59:12 +0400 |
| commit | c8cbee61c9d53ee28473ad33bbb54f6a88f5e3af (patch) | |
| tree | ad0b767e80ef169ad319860274482ae0bbf8ab4c /arch/i386 | |
| parent | e5d2861f31474b373ce7754dc5122b414a176c64 (diff) | |
| download | linux-c8cbee61c9d53ee28473ad33bbb54f6a88f5e3af.tar.xz | |
ACPI: preserve the ebx value in acpi_copy_wakeup_routine
Register %ebx serves as the "global offset table base register" for
position-independent code. For absolute code, %ebx serves as a local
register and has no specified role in the function calling sequence. In
either case, a function must preserve the register value for the caller.
acpi_copy_wakeup_routine overrides %ebx without saving it, this may corrupt
the called data.
Kevin found that most time the value of Sx is saved in %esi, however
sometimes compiler also uses %ebx. When this happens, suspends fails since
sleep value in ebx is changed by acpi_copy_wakeup_routine.
The same funtion in X86_64 doesn't have this problem.
Signed-off-by: Zhang Rui <rui.zhang@intel.com>
Looks-okay-to: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Cc: Len Brown <lenb@kernel.org>
Acked-by: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'arch/i386')
| -rw-r--r-- | arch/i386/kernel/acpi/wakeup.S | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/arch/i386/kernel/acpi/wakeup.S b/arch/i386/kernel/acpi/wakeup.S index b781b38131c0..a2295a34b2c7 100644 --- a/arch/i386/kernel/acpi/wakeup.S +++ b/arch/i386/kernel/acpi/wakeup.S @@ -230,6 +230,7 @@ bogus_magic: # ENTRY(acpi_copy_wakeup_routine) + pushl %ebx sgdt saved_gdt sidt saved_idt sldt saved_ldt @@ -263,6 +264,7 @@ ENTRY(acpi_copy_wakeup_routine) movl %edx, video_flags - wakeup_start (%eax) movl $0x12345678, real_magic - wakeup_start (%eax) movl $0x12345678, saved_magic + popl %ebx ret save_registers: |