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| author | H. Peter Anvin <hpa@zytor.com> | 2008-08-25 22:39:15 -0700 |
|---|---|---|
| committer | H. Peter Anvin <hpa@zytor.com> | 2008-08-25 22:39:15 -0700 |
| commit | 08970fc4e0385790a7b093adfaa4165a189f9eb0 (patch) | |
| tree | 9a7ca00d88f64ba69abb3cc1cb7a4a803033b12a /include | |
| parent | 9ea2b82ed6265a31f9a84886d74d8a2ef01b27c8 (diff) | |
| download | linux-08970fc4e0385790a7b093adfaa4165a189f9eb0.tar.bz2 | |
x86: msr: fix bogus return values from rdmsr_safe/wrmsr_safe
Impact: bogus error codes (+other?) on x86-64
The rdmsr_safe/wrmsr_safe routines have macros for the handling of the
edx:eax arguments. Those macros take a variable number of assembly
arguments. This is rather inherently incompatible with using
%digit-style escapes in the inline assembly; replace those with
%[name]-style escapes.
This fixes miscompilation on x86-64, which at the very least caused
bogus return values. It is possible that this could also corrupt the
return value; I am not sure.
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Diffstat (limited to 'include')
| -rw-r--r-- | include/asm-x86/msr.h | 16 |
1 files changed, 8 insertions, 8 deletions
diff --git a/include/asm-x86/msr.h b/include/asm-x86/msr.h index ad5f2decf7f7..2362cfda1fbc 100644 --- a/include/asm-x86/msr.h +++ b/include/asm-x86/msr.h @@ -52,14 +52,14 @@ static inline unsigned long long native_read_msr_safe(unsigned int msr, { DECLARE_ARGS(val, low, high); - asm volatile("2: rdmsr ; xor %0,%0\n" + asm volatile("2: rdmsr ; xor %[err],%[err]\n" "1:\n\t" ".section .fixup,\"ax\"\n\t" - "3: mov %3,%0 ; jmp 1b\n\t" + "3: mov %[fault],%[err] ; jmp 1b\n\t" ".previous\n\t" _ASM_EXTABLE(2b, 3b) - : "=r" (*err), EAX_EDX_RET(val, low, high) - : "c" (msr), "i" (-EFAULT)); + : [err] "=r" (*err), EAX_EDX_RET(val, low, high) + : "c" (msr), [fault] "i" (-EFAULT)); return EAX_EDX_VAL(val, low, high); } @@ -73,15 +73,15 @@ static inline int native_write_msr_safe(unsigned int msr, unsigned low, unsigned high) { int err; - asm volatile("2: wrmsr ; xor %0,%0\n" + asm volatile("2: wrmsr ; xor %[err],%[err]\n" "1:\n\t" ".section .fixup,\"ax\"\n\t" - "3: mov %4,%0 ; jmp 1b\n\t" + "3: mov %[fault],%[err] ; jmp 1b\n\t" ".previous\n\t" _ASM_EXTABLE(2b, 3b) - : "=a" (err) + : [err] "=a" (err) : "c" (msr), "0" (low), "d" (high), - "i" (-EFAULT) + [fault] "i" (-EFAULT) : "memory"); return err; } |