Re: [PATCH v20 07/25] x86/mm: Remove _PAGE_DIRTY from kernel RO pages

Kees Cook
2021-02-10T19:37:23Z

On Wed, Feb 10, 2021 at 09:56:45AM -0800, Yu-cheng Yu wrote:
> The x86 family of processors do not directly create read-only and Dirty
> PTEs. These PTEs are created by software. One such case is that kernel
> read-only pages are historically setup as Dirty.
>
> New processors that support Shadow Stack regard read-only and Dirty PTEs as
> shadow stack pages. This results in ambiguity between shadow stack and
> kernel read-only pages. To resolve this, removed Dirty from kernel read-
> only pages.
>
> Signed-off-by: Yu-cheng Yu <yu-cheng.yu@intel.com>

Reviewed-by: Kees Cook <keescook@chromium.org>

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Kees Cook