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authorH. Peter Anvin <hpa@zytor.com>2008-08-25 22:39:15 -0700
committerH. Peter Anvin <hpa@zytor.com>2008-08-25 22:39:15 -0700
commit08970fc4e0385790a7b093adfaa4165a189f9eb0 (patch)
tree9a7ca00d88f64ba69abb3cc1cb7a4a803033b12a
parent9ea2b82ed6265a31f9a84886d74d8a2ef01b27c8 (diff)
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>
-rw-r--r--include/asm-x86/msr.h16
1 files changed, 8 insertions, 8 deletions
diff --git a/include/asm-x86/msr.h b/include/asm-x86/msr.h
index ad5f2decf7f..2362cfda1fb 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;
}