Re: [tip:x86/pti] x86/cpu_entry_area: Sync cpu_entry_area to initial_page_table

From: Ingo Molnar
Date: Thu Mar 01 2018 - 04:31:26 EST



Just a few small speling nits:

* tip-bot for Thomas Gleixner <tipbot@xxxxxxxxx> wrote:

> Commit-ID: 945fd17ab6bab8a4d05da6c3170519fbcfe62ddb
> Gitweb: https://git.kernel.org/tip/945fd17ab6bab8a4d05da6c3170519fbcfe62ddb
> Author: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
> AuthorDate: Wed, 28 Feb 2018 21:14:26 +0100
> Committer: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
> 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