The patch titled
x86: fix dubious segment register clear in cpu_init()
has been added to the -mm tree. Its filename is
x86-fix-dubious-segment-register-clear-in-cpu_init.patch
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
------------------------------------------------------
Subject: x86: fix dubious segment register clear in cpu_init()
From: Jeremy Fitzhardinge <jeremy@xxxxxxxx>
Fix a very dubious piece of code in
arch/i386/kernel/cpu/common.c:cpu_init(). This clears out %fs and %gs, but
clobbers %eax in the process without telling gcc. It turns out that gcc
happens to be not using %eax at that point anyway so it doesn't matter
much, but it looks like a bomb waiting to go off.
This does end up saving an instruction, because gcc wants %eax==0 for the
set_debugreg()s below.
Signed-off-by: Jeremy Fitzhardinge <jeremy@xxxxxxxx>
Cc: Zachary Amsden <zach@xxxxxxxxxx>
Cc: Andi Kleen <ak@xxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxx>
---
arch/i386/kernel/cpu/common.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff -puN arch/i386/kernel/cpu/common.c~x86-fix-dubious-segment-register-clear-in-cpu_init arch/i386/kernel/cpu/common.c
--- a/arch/i386/kernel/cpu/common.c~x86-fix-dubious-segment-register-clear-in-cpu_init
+++ a/arch/i386/kernel/cpu/common.c
@@ -675,7 +675,7 @@ old_gdt:
#endif
/* Clear %fs and %gs. */
- asm volatile ("xorl %eax, %eax; movl %eax, %fs; movl %eax, %gs");
+ asm volatile ("movl %0, %%fs; movl %0, %%gs" : : "r" (0));
/* Clear all 6 debug registers: */
set_debugreg(0, 0);
_
Patches currently in -mm which might be from jeremy@xxxxxxxx are
git-cpufreq.patch
x86-fix-dubious-segment-register-clear-in-cpu_init.patch
-
To unsubscribe from this list: send the line "unsubscribe mm-commits" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
