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Date: Wed, 24 Sep 2014 11:42:16 -0700
From: "H. Peter Anvin" <hpa@zytor.com>
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To: "Bryan O'Donoghue" <pure.logic@nexus-software.ie>,
	mingo@kernel.org, linux-kernel@vger.kernel.org, tglx@linutronix.de,
	stable@vger.kernel.org, bp@alien8.de,
	linux-tip-commits@vger.kernel.org
Subject: Re: [tip:x86/platform] x86/intel/quark: Switch off CR4.PGE so TLB
 flush uses CR3 instead
References: <1411514784-14885-1-git-send-email-pure.logic@nexus-software.ie> <tip-ee1b5b165c0a2f04d2107e634e51f05d0eb107de@git.kernel.org> <5422E8D0.5080705@zytor.com> <5422EA13.1080706@nexus-software.ie> <5422EC30.10206@nexus-software.ie>
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On 09/24/2014 09:07 AM, Bryan O'Donoghue wrote:
>>
>> So __flush_tlb_all(); will do nothing but that's OK since load_cr3()
>> already flushed the TLB - including any PTE with PGE set
> 
> I take your point though.
> 
> It's probably better to be explicit and do the whole
> 
> if (quark)
>     __flush_tlb();
> else
>     __flush_tlb_all();
> 
> So that we aren't relying on the side effects of the previous statement.
> 

Well, we need a comment at least.

	-hpa