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Date: Thu, 24 Jul 2014 05:23:54 +0000 From: "Ren, Qiaowei" <qiaowei.ren@...el.com> To: "Hansen, Dave" <dave.hansen@...el.com>, "H. Peter Anvin" <hpa@...or.com>, Thomas Gleixner <tglx@...utronix.de>, Ingo Molnar <mingo@...hat.com> CC: "x86@...nel.org" <x86@...nel.org>, "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>, "linux-mm@...ck.org" <linux-mm@...ck.org> Subject: RE: [PATCH v7 03/10] x86, mpx: add macro cpu_has_mpx On 2014-07-24, Hansen, Dave wrote: > On 07/23/2014 05:56 PM, Ren, Qiaowei wrote: >> 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/c >>>> om >>>> 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? > > That's better. Is it really disabling MPX, though? > > And shouldn't we clear the cpu feature bit too? I am not sure. I am suspecting whether this checking should be moved before xstate_enable(). Peter, what do you think of it? Thanks, Qiaowei -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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