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intrin.h: Fix up bugs in the cr3 and msr intrinsics 

Don't include input and output regs in clobbers.  Prefix some
identifiers with __.  Add a memory constraint to __readcr3 to prevent
reordering.  This constraint is heavy handed, but conservatively
correct.

Thanks to PaX Team for the suggestions.

llvm-svn: 205778
This commit is contained in:
Reid Kleckner 2014-04-08 17:49:16 +00:00
parent 2541d4e525
commit 6df5254d6f
1 changed files with 6 additions and 9 deletions
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15
clang/lib/Headers/Intrin.h
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@ -997,23 +997,20 @@ __readmsr(unsigned long __register) {
// undefined.
unsigned long __edx;
unsigned long __eax;
__asm__ ("rdmsr"
: "=d"(__edx), "=a"(__eax)
: "c"(__register)
: "%ecx", "%edx", "%eax");
__asm__ ("rdmsr" : "=d"(__edx), "=a"(__eax) : "c"(__register));
return (((unsigned __int64)__edx) << 32) | (unsigned __int64)__eax;
}
static __inline__ unsigned long __attribute__((always_inline, __nodebug__))
__readcr3(void) {
unsigned long value;
__asm__ __volatile__("mov %%cr3, %0" : "=q"(value));
return value;
unsigned long __cr3_val;
__asm__ __volatile__ ("mov %%cr3, %0" : "=q"(__cr3_val) : : "memory");
return __cr3_val;
}
static __inline__ void __attribute__((always_inline, __nodebug__))
__writecr3(unsigned int Data) {
__asm__("mov %0, %%cr3" : : "q"(Data) : "memory");
__writecr3(unsigned int __cr3_val) {
__asm__ ("mov %0, %%cr3" : : "q"(__cr3_val) : "memory");
}
#ifdef __cplusplus