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authorH. Peter Anvin <hpa@zytor.com>2008-08-26 01:39:15 -0400
committerH. Peter Anvin <hpa@zytor.com>2008-08-26 01:39:15 -0400
commit08970fc4e0385790a7b093adfaa4165a189f9eb0 (patch)
tree9a7ca00d88f64ba69abb3cc1cb7a4a803033b12a /include
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>
Diffstat (limited to 'include')
-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 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,
52{ 52{
53 DECLARE_ARGS(val, low, high); 53 DECLARE_ARGS(val, low, high);
54 54
55 asm volatile("2: rdmsr ; xor %0,%0\n" 55 asm volatile("2: rdmsr ; xor %[err],%[err]\n"
56 "1:\n\t" 56 "1:\n\t"
57 ".section .fixup,\"ax\"\n\t" 57 ".section .fixup,\"ax\"\n\t"
58 "3: mov %3,%0 ; jmp 1b\n\t" 58 "3: mov %[fault],%[err] ; jmp 1b\n\t"
59 ".previous\n\t" 59 ".previous\n\t"
60 _ASM_EXTABLE(2b, 3b) 60 _ASM_EXTABLE(2b, 3b)
61 : "=r" (*err), EAX_EDX_RET(val, low, high) 61 : [err] "=r" (*err), EAX_EDX_RET(val, low, high)
62 : "c" (msr), "i" (-EFAULT)); 62 : "c" (msr), [fault] "i" (-EFAULT));
63 return EAX_EDX_VAL(val, low, high); 63 return EAX_EDX_VAL(val, low, high);
64} 64}
65 65
@@ -73,15 +73,15 @@ static inline int native_write_msr_safe(unsigned int msr,
73 unsigned low, unsigned high) 73 unsigned low, unsigned high)
74{ 74{
75 int err; 75 int err;
76 asm volatile("2: wrmsr ; xor %0,%0\n" 76 asm volatile("2: wrmsr ; xor %[err],%[err]\n"
77 "1:\n\t" 77 "1:\n\t"
78 ".section .fixup,\"ax\"\n\t" 78 ".section .fixup,\"ax\"\n\t"
79 "3: mov %4,%0 ; jmp 1b\n\t" 79 "3: mov %[fault],%[err] ; jmp 1b\n\t"
80 ".previous\n\t" 80 ".previous\n\t"
81 _ASM_EXTABLE(2b, 3b) 81 _ASM_EXTABLE(2b, 3b)
82 : "=a" (err) 82 : [err] "=a" (err)
83 : "c" (msr), "0" (low), "d" (high), 83 : "c" (msr), "0" (low), "d" (high),
84 "i" (-EFAULT) 84 [fault] "i" (-EFAULT)
85 : "memory"); 85 : "memory");
86 return err; 86 return err;
87} 87}