linux-kernel - Re: [tip:x86/platform] x86/intel/quark: Switch off CR4.PGE so TLB flush uses CR3 instead

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Message-ID: <542310E3.90803@zytor.com>
Date:	Wed, 24 Sep 2014 11:43:47 -0700
From:	"H. Peter Anvin" <hpa@...or.com>
To:	"Bryan O'Donoghue" <pure.logic@...us-software.ie>,
	mingo@...nel.org, linux-kernel@...r.kernel.org, tglx@...utronix.de,
	stable@...r.kernel.org, bp@...en8.de,
	linux-tip-commits@...r.kernel.org
Subject: Re: [tip:x86/platform] x86/intel/quark: Switch off CR4.PGE so TLB
 flush uses CR3 instead

On 09/24/2014 11:42 AM, H. Peter Anvin wrote:
> 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.
> 

And certainly we don't need an if/else as we can just do it.

	-hpa


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