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From: Ingo Molnar <mingo@kernel.org>
To: tglx@linutronix.de, hpa@zytor.com, linux-kernel@vger.kernel.org,
	william.grant@canonical.com, terraluna977@gmail.com
Cc: linux-tip-commits@vger.kernel.org
Subject: Re: [tip:x86/pti] x86/cpu_entry_area: Sync cpu_entry_area to initial_page_table
Date: Thu, 1 Mar 2018 10:31:11 +0100	[thread overview]
Message-ID: <20180301093111.kyskbidqe5fqvogs@gmail.com> (raw)
In-Reply-To: <tip-945fd17ab6bab8a4d05da6c3170519fbcfe62ddb@git.kernel.org>


Just a few small speling nits:

* tip-bot for Thomas Gleixner <tipbot@zytor.com> wrote:

> Commit-ID:  945fd17ab6bab8a4d05da6c3170519fbcfe62ddb
> Gitweb:     https://git.kernel.org/tip/945fd17ab6bab8a4d05da6c3170519fbcfe62ddb
> Author:     Thomas Gleixner <tglx@linutronix.de>
> AuthorDate: Wed, 28 Feb 2018 21:14:26 +0100
> Committer:  Thomas Gleixner <tglx@linutronix.de>
> CommitDate: Thu, 1 Mar 2018 09:48:27 +0100
> 
> x86/cpu_entry_area: Sync cpu_entry_area to initial_page_table
> 
> The separation of the cpu_entry_area from the fixmap missed the fact that
> on 32bit non-PAE kernels the cpu_entry_area mapping might not be covered in
> initial_page_table by the previous synchronizations.
> 
> This results in suspend/resume failures because 32bit utilizes initial page
> table for resume. The absence of the cpu_entry_area mapping results in a
> triple fault, aka. insta reboot.
> 
> With PAE enabled this works by chance because the PGD entry which covers
> the fixmap and other parts incindentally provides the cpu_entry_area
> mapping as well.

s/incindentally/incidentally

s/32bit/32-bit

s/utilizes initial page table
 /utilizes the initial page table

> Synchronize the initial page table after setting up the cpu entry
> area. Instead of adding yet another copy of the same code, move it to a
> function and invoke it from the various places.

s/cpu/CPU

> It needs to be investigated if the existing calls in setup_arch() and
> setup_per_cpu_areas() can be replaced by the later invocation from
> setup_cpu_entry_areas(), but that's beyond the scope of this fix.

> +	/*
> +	 * This is the last essential update to swapper_pgdir which needs
> +	 * to be synchronized to initial_page_table on 32bit.
> +	 */
> +	sync_initial_page_table();


s/swapper_pgdir
 /swapper_pg_dir

s/on 32bit/on 32-bit kernels

> +	/*
> +	 * sync back low identity map too.  It is used for example
> +	 * in the 32-bit EFI stub.
> +	 */

s/sync/Sync

Very nice fix!

Thanks,

	Ingo

      reply	other threads:[~2018-03-01  9:31 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-02-27 12:54 4.16 regression: s2ram broken on non-PAE i686 Woody Suwalski
2018-02-28  8:59 ` Thomas Gleixner
2018-02-28 10:46   ` Woody Suwalski
2018-02-28 21:20     ` Thomas Gleixner
2018-03-01  2:45       ` Woody Suwalski
2018-03-01  7:35         ` Thomas Gleixner
2018-03-01  8:51       ` [tip:x86/pti] x86/cpu_entry_area: Sync cpu_entry_area to initial_page_table tip-bot for Thomas Gleixner
2018-03-01  9:31         ` Ingo Molnar [this message]

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