Attachment 574671 Details for Bug 809014 – Proposed fix

[patch] Proposed fix

fix.patch (text/plain), 1.00 KB, created by Jeremy Fitzhardinge on 2012-04-02 23:06:24 UTC

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Creator: Jeremy Fitzhardinge

Created: 2012-04-02 23:06:24 UTC

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patch

obsolete

>From 7b8ed6e628e874a27abae309a1308d86bcefc7f5 Mon Sep 17 00:00:00 2001
>From: Jeremy Fitzhardinge <jeremy@goop.org>
>Date: Mon, 2 Apr 2012 16:02:10 -0700
>Subject: [PATCH] x86: use 'q' constraint for byte operands on xchg macro
>
>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>
>
>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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Attachments on bug 809014: 574671