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From: Thomas Gleixner <tglx@linutronix.de>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Song Liu <songliubraving@fb.com>,
	linux-kernel@vger.kernel.org,  linux-mm@kvack.org,
	kernel-team@fb.com, stable@vger.kernel.org,
	 Joerg Roedel <jroedel@suse.de>,
	Dave Hansen <dave.hansen@linux.intel.com>,
	 Andy Lutomirski <luto@kernel.org>
Subject: Re: [PATCH] x86/mm/pti: in pti_clone_pgtable() don't increase addr by PUD_SIZE
Date: Tue, 20 Aug 2019 13:16:41 +0200 (CEST)	[thread overview]
Message-ID: <alpine.DEB.2.21.1908201315450.2223@nanos.tec.linutronix.de> (raw)
In-Reply-To: <20190820100055.GI2332@hirez.programming.kicks-ass.net>

On Tue, 20 Aug 2019, Peter Zijlstra wrote:
> What that code wants to do is skip to the end of the pud, a pmd_size
> increase will not do that. And right below this, there's a second
> instance of this exact pattern.
> 
> Did I get the below right?
> 
> ---
> diff --git a/arch/x86/mm/pti.c b/arch/x86/mm/pti.c
> index b196524759ec..32b20b3cb227 100644
> --- a/arch/x86/mm/pti.c
> +++ b/arch/x86/mm/pti.c
> @@ -330,12 +330,14 @@ pti_clone_pgtable(unsigned long start, unsigned long end,
>  
>  		pud = pud_offset(p4d, addr);
>  		if (pud_none(*pud)) {
> +			addr &= PUD_MASK;
>  			addr += PUD_SIZE;

			round_up(addr, PUD_SIZE);

perhaps?

>  			continue;
>  		}
>  
>  		pmd = pmd_offset(pud, addr);
>  		if (pmd_none(*pmd)) {
> +			addr &= PMD_MASK;
>  			addr += PMD_SIZE;
>  			continue;
>  		}
> 


  reply	other threads:[~2019-08-20 11:16 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-08-20  7:51 Song Liu
2019-08-20  9:12 ` Thomas Gleixner
2019-08-20 13:17   ` Song Liu
2019-08-20 10:00 ` Peter Zijlstra
2019-08-20 11:16   ` Thomas Gleixner [this message]
2019-08-20 13:21     ` Song Liu
2019-08-20 13:39       ` Thomas Gleixner
2019-08-20 13:55       ` Rik van Riel
2019-08-20 14:00         ` Song Liu
2019-08-20 16:56           ` [PATCH v2] " Rik van Riel
2019-08-20 13:21     ` [PATCH] " Rik van Riel
2019-08-20 13:19   ` Song Liu
2019-08-20 13:57 ` Dave Hansen
2019-08-20 14:14   ` Song Liu
2019-08-20 14:18     ` Dave Hansen
2019-08-20 16:05       ` Song Liu
2019-08-20 16:38         ` Song Liu

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