提交 2ca052a3 编写于 作者: J Jeremy Fitzhardinge 提交者: H. Peter Anvin

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: NJeremy Fitzhardinge <jeremy@goop.org>
Link: http://lkml.kernel.org/r/4F7A3315.501@goop.orgReported-by: NLeigh Scott <leigh123linux@googlemail.com>
Tested-by: NThomas Reitmayr <treitmayr@devbase.at>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>
Cc: <stable@vger.kernel.org> v3.3
上级 46ed99d1
...@@ -43,7 +43,7 @@ extern void __add_wrong_size(void) ...@@ -43,7 +43,7 @@ extern void __add_wrong_size(void)
switch (sizeof(*(ptr))) { \ switch (sizeof(*(ptr))) { \
case __X86_CASE_B: \ case __X86_CASE_B: \
asm volatile (lock #op "b %b0, %1\n" \ asm volatile (lock #op "b %b0, %1\n" \
: "+r" (__ret), "+m" (*(ptr)) \ : "+q" (__ret), "+m" (*(ptr)) \
: : "memory", "cc"); \ : : "memory", "cc"); \
break; \ break; \
case __X86_CASE_W: \ case __X86_CASE_W: \
......
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