forked from luck/tmp_suning_uos_patched
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>
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@ -230,6 +230,7 @@ bogus_magic:
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#
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ENTRY(acpi_copy_wakeup_routine)
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pushl %ebx
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sgdt saved_gdt
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sidt saved_idt
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sldt saved_ldt
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@ -263,6 +264,7 @@ ENTRY(acpi_copy_wakeup_routine)
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movl %edx, video_flags - wakeup_start (%eax)
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movl $0x12345678, real_magic - wakeup_start (%eax)
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movl $0x12345678, saved_magic
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popl %ebx
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ret
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save_registers:
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