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From: "Bryan O'Donoghue" <pure.logic@nexus-software.ie>
To: "H. Peter Anvin" <hpa@zytor.com>,
	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
Date: Wed, 24 Sep 2014 16:58:11 +0100	[thread overview]
Message-ID: <5422EA13.1080706@nexus-software.ie> (raw)
In-Reply-To: <5422E8D0.5080705@zytor.com>


>
> I believe there is one more change needed: there is a __flush_tlb_all()
> in the early code which gets executed before the above code runs; the
> easiest fix is to just add a __flush_tlb() immediately after it.
>
> This should have been pushed upstream, and not stayed in the BSP kernel.

Peter.

You're talking about void __init setup_arch() right ?

The code looks like this

load_cr3(swapper_pg_dir);
__flush_tlb_all();

Note that on Quark the method to invalidate the TLB is by reloading CR3 
- which is immediately prior to __flush_tlb_all();

So __flush_tlb_all(); will do nothing but that's OK since load_cr3() 
already flushed the TLB - including any PTE with PGE set


Best,
Bryan

  reply	other threads:[~2014-09-24 15:58 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <1411514784-14885-1-git-send-email-pure.logic@nexus-software.ie>
     [not found] ` <20140924071221.GB990@gmail.com>
2014-09-24 10:15   ` [PATCH] x86: Quark: Switch of CR4.PGE TLB flush use CR3 instead Bryan O'Donoghue
2014-09-24 15:01 ` [tip:x86/platform] x86/intel/quark: Switch off CR4.PGE so TLB flush uses " tip-bot for Bryan O'Donoghue
2014-09-24 15:52   ` H. Peter Anvin
2014-09-24 15:58     ` Bryan O'Donoghue [this message]
2014-09-24 16:07       ` Bryan O'Donoghue
2014-09-24 18:42         ` H. Peter Anvin
2014-09-24 18:43           ` H. Peter Anvin
2014-09-24 20:22             ` Bryan O'Donoghue

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