Re: [PATCH 03 of 36] x86: add memory barriers to wrmsr

Jeremy Fitzhardinge
2008-06-25T23:06:33Z

Arjan van de Ven wrote:
> On Wed, 25 Jun 2008 14:08:57 -0700
> Jeremy Fitzhardinge <jeremy@goop.org> wrote:
>
>
>> Arjan van de Ven wrote:
>>
>>> it's more readable for several of these cases to stick a barrier();
>>> in front and after it to be honest; that makes it more explicit that
>>> these are deliberate compiler barriers rather than "actual" memory
>>> access...
>>>
>>>
>>>
>> I suppose, though I would be inclined to put the barriers in the
>> wrmsr macro itself to act as documentation.
>>
>
>
> yeah I meant like this:
>
> static inline void native_write_msr(unsigned int msr,
> unsigned low, unsigned high)
> {
> barrier();
> asm volatile("wrmsr" : : "c" (msr), "a"(low), "d" (high));
> barrier();
> }
>
> or in the same in the thing that calls this.
>
>

OK, we're in vehement agreement then.

J