Re: [PATCH v2 5/6] x86/cpu: Remove "noexec"

Kees Cook
2022-02-07T22:25:49Z

On Thu, Jan 27, 2022 at 12:56:25PM +0100, Borislav Petkov wrote:
> From: Borislav Petkov <bp@suse.de>
>
> It doesn't make any sense to disable non-executable mappings -
> security-wise or else.
>
> So rip out that switch and move the remaining code into setup.c and
> delete setup_nx.c
>
> Signed-off-by: Borislav Petkov <bp@suse.de>
> Reviewed-by: Lai Jiangshan <jiangshanlai@gmail.com>

I've dug through the nx fun again. The verify_cpu() calls are untouched
(which were the most fiddly part of all that a decade ago), so that's
good. The early handling of __supported_pte_mask in x86_configure_nx()
is untouched and the call is retained before the param processing for
the set_fixmap() dance, so everything I can remember as being "difficult"
with NX ordering here looks good.

Thanks for cleaning all this up!

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

--
Kees Cook