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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: Jike Song <albcamus@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
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@ -22,10 +22,10 @@ static inline unsigned long long native_read_tscp(unsigned int *aux)
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}
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/*
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* i386 calling convention returns 64-bit value in edx:eax, while
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* x86_64 returns at rax. Also, the "A" constraint does not really
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* mean rdx:rax in x86_64, so we need specialized behaviour for each
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* architecture
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* both i386 and x86_64 returns 64-bit value in edx:eax, but gcc's "A"
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* constraint has different meanings. For i386, "A" means exactly
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* edx:eax, while for x86_64 it doesn't mean rdx:rax or edx:eax. Instead,
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* it means rax *or* rdx.
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*/
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#ifdef CONFIG_X86_64
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#define DECLARE_ARGS(val, low, high) unsigned low, high
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