The patch titled
ACPI: preserve the ebx value in acpi_copy_wakeup_routine
has been added to the -mm tree. Its filename is
acpi-preserve-the-ebx-value-in-acpi_copy_wakeup_routine.patch
*** Remember to use Documentation/SubmitChecklist when testing your code ***
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
------------------------------------------------------
Subject: ACPI: preserve the ebx value in acpi_copy_wakeup_routine
From: Tian Kevin <kevin.tian@xxxxxxxxx>
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@xxxxxxxxx>
Looks-okay-to: Pavel Machek <pavel@xxxxxx>
Signed-off-by: Rafael J. Wysocki <rjw@xxxxxxx>
Cc: Len Brown <lenb@xxxxxxxxxx>
Cc: Andi Kleen <ak@xxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
arch/i386/kernel/acpi/wakeup.S | 2 ++
1 files changed, 2 insertions(+)
diff -puN arch/i386/kernel/acpi/wakeup.S~acpi-preserve-the-ebx-value-in-acpi_copy_wakeup_routine arch/i386/kernel/acpi/wakeup.S
--- a/arch/i386/kernel/acpi/wakeup.S~acpi-preserve-the-ebx-value-in-acpi_copy_wakeup_routine
+++ a/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:
_
Patches currently in -mm which might be from kevin.tian@xxxxxxxxx are
acpi-preserve-the-ebx-value-in-acpi_copy_wakeup_routine.patch
-
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