Messages in this thread Patch in this message | | | Date | Mon, 02 Apr 2012 16:15:33 -0700 | From | Jeremy Fitzhardinge <> | Subject | [PATCH] Use correct byte-sized register constraint in __xchg_op() |
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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> Reported-by: Leigh Scott <leigh123linux@googlemail.com> Tested-by: Thomas Reitmayr <treitmayr@devbase.at>
diff --git a/arch/x86/include/asm/cmpxchg.h b/arch/x86/include/asm/cmpxchg.h index b3b7332..bc18d0e 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: \
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