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Commit d4f1b103 authored by Jike Song's avatar Jike Song Committed by Ingo Molnar
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x86: clean up comments wrt. rd{msr|tsc|pmc} 



The rdmsr instruction(et al) for i386 and x86-64 are semantically same.
The only difference is how gcc interpret constraint "A" for these targets.

Signed-off-by: default avatarJike Song <albcamus@gmail.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 2011a067

arch/x86/include/asm/msr.h

+4 −4
Original line number Diff line number Diff line
@@ -22,10 +22,10 @@ static inline unsigned long long native_read_tscp(unsigned int *aux) 
}



/*

 * i386 calling convention returns 64-bit value in edx:eax, while

 * x86_64 returns at rax. Also, the "A" constraint does not really

 * mean rdx:rax in x86_64, so we need specialized behaviour for each

 * architecture

 * both i386 and x86_64 returns 64-bit value in edx:eax, but gcc's "A"

 * constraint has different meanings. For i386, "A" means exactly

 * edx:eax, while for x86_64 it doesn't mean rdx:rax or edx:eax. Instead,

 * it means rax *or* rdx.

 */

#ifdef CONFIG_X86_64

#define DECLARE_ARGS(val, low, high)	unsigned low, high