33 lines
1.3 KiB
Diff
33 lines
1.3 KiB
Diff
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From: Jeremy Fitzhardinge <jeremy@goop.org>
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Date: Mon, 2 Apr 2012 23:15:33 +0000 (-0700)
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Subject: x86: Use correct byte-sized register constraint in __xchg_op()
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X-Git-Url: http://git.kernel.org/?p=linux%2Fkernel%2Fgit%2Ftip%2Ftip.git;a=commitdiff_plain;h=2ca052a3710fac208eee690faefdeb8bbd4586a1
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x86: 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
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it with a subset of registers. 'r' causes compilation failures on i386,
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but 'q' expresses the constraint properly.
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Signed-off-by: Jeremy Fitzhardinge <jeremy@goop.org>
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Link: http://lkml.kernel.org/r/4F7A3315.501@goop.org
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Reported-by: Leigh Scott <leigh123linux@googlemail.com>
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Tested-by: Thomas Reitmayr <treitmayr@devbase.at>
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Signed-off-by: H. Peter Anvin <hpa@zytor.com>
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Cc: <stable@vger.kernel.org> v3.3
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---
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diff --git a/arch/x86/include/asm/cmpxchg.h b/arch/x86/include/asm/cmpxchg.h
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index b3b7332..bc18d0e 100644
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--- a/arch/x86/include/asm/cmpxchg.h
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+++ b/arch/x86/include/asm/cmpxchg.h
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@@ -43,7 +43,7 @@ extern void __add_wrong_size(void)
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switch (sizeof(*(ptr))) { \
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case __X86_CASE_B: \
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asm volatile (lock #op "b %b0, %1\n" \
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- : "+r" (__ret), "+m" (*(ptr)) \
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+ : "+q" (__ret), "+m" (*(ptr)) \
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: : "memory", "cc"); \
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break; \
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case __X86_CASE_W: \
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