RE: [PATCH v7 03/10] x86, mpx: add macro cpu_has_mpx

From: Ren, Qiaowei
Date: Wed Jul 23 2014 - 20:57:13 EST




On 2014-07-24, Hansen, Dave wrote:
> On 07/22/2014 07:35 PM, Ren, Qiaowei wrote:
>> The checking about MPX feature should be as follow:
>>
>> if (pcntxt_mask & XSTATE_EAGER) {
>> if (eagerfpu == DISABLE) {
>> pr_err("eagerfpu not present, disabling some
> xstate features: 0x%llx\n",
>> pcntxt_mask &
> XSTATE_EAGER);
>> pcntxt_mask &= ~XSTATE_EAGER; } else { eagerfpu
>> = ENABLE;
>> }
>> }
>> This patch was merged into kernel the ending of last year
>> (https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/com
>> mi
>> t/?id=e7d820a5e549b3eb6c3f9467507566565646a669 )
>
> Should we be doing a clear_cpu_cap(X86_FEATURE_MPX) in here?
>
> This isn't major, but I can't _ever_ imagine a user being able to
> track down why MPX is not working from this message. Should we spruce it up somehow?

Maybe. If the error log "disabling some xstate features:" is changed to "disabling MPX xstate features:", do you think it is OK?

Thanks,
Qiaowei

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