Re: [PATCH] x86_64: remove wrong setting about CONSTANT_TSC for intel cpu
From: Yinghai Lu
Date: Tue Feb 26 2008 - 02:25:14 EST
On Mon, Feb 25, 2008 at 11:20 PM, Ingo Molnar <mingo@xxxxxxx> wrote:
>
> * Yinghai Lu <Yinghai.Lu@xxxxxxx> wrote:
>
>
> > also fix error in early_init_intel and reference about x86_capality,
> > because it is array already.., prevent possible data corruption...
>
> hm, why should there be data corruption:
>
>
> > - set_bit(X86_FEATURE_CONSTANT_TSC, &c->x86_capability);
> > + set_cpu_cap(c, X86_FEATURE_CONSTANT_TSC);
>
> cpu_cpu_cap() is currently defined as:
>
> #define set_cpu_cap(c, bit) set_bit(bit, (unsigned long *)((c)->x86_capability)
>
> which is the same. set_cpu_cap() is indeed the cleaner form to do this
> so your patch is correct as a cleanup.
set_cpu_cap is right
==
set_bit(X86_FEATURE_CONSTANT_TSC, &c->x86_capability); ===> is wrong
should be
set_bit(X86_FEATURE_CONSTANT_TSC, c->x86_capability);
x86_capability is a array ...
so this could prevent some data corruption.
YH
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