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authorJeremy Fitzhardinge <jeremy@goop.org>2012-04-03 01:15:33 +0200
committerH. Peter Anvin <hpa@zytor.com>2012-04-06 18:39:39 +0200
commit2ca052a3710fac208eee690faefdeb8bbd4586a1 (patch)
treec05a7c607f6f1b7065834e43540a2514b5d9257b
parentx86: vsyscall: Use NULL instead 0 for a pointer argument (diff)
downloadlinux-2ca052a3710fac208eee690faefdeb8bbd4586a1.tar.xz
linux-2ca052a3710fac208eee690faefdeb8bbd4586a1.zip
x86: Use correct byte-sized register constraint in __xchg_op()
x86-64 can access the low half of any register, but i386 can only do it with a subset of registers. 'r' causes compilation failures on i386, but 'q' expresses the constraint properly. Signed-off-by: Jeremy Fitzhardinge <jeremy@goop.org> Link: http://lkml.kernel.org/r/4F7A3315.501@goop.org Reported-by: Leigh Scott <leigh123linux@googlemail.com> Tested-by: Thomas Reitmayr <treitmayr@devbase.at> Signed-off-by: H. Peter Anvin <hpa@zytor.com> Cc: <stable@vger.kernel.org> v3.3
-rw-r--r--arch/x86/include/asm/cmpxchg.h2
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/x86/include/asm/cmpxchg.h b/arch/x86/include/asm/cmpxchg.h
index b3b733262909..bc18d0ed459a 100644
--- a/arch/x86/include/asm/cmpxchg.h
+++ b/arch/x86/include/asm/cmpxchg.h
@@ -43,7 +43,7 @@ extern void __add_wrong_size(void)
switch (sizeof(*(ptr))) { \
case __X86_CASE_B: \
asm volatile (lock #op "b %b0, %1\n" \
- : "+r" (__ret), "+m" (*(ptr)) \
+ : "+q" (__ret), "+m" (*(ptr)) \
: : "memory", "cc"); \
break; \
case __X86_CASE_W: \