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

[Kees Cook]

On Thu, Jan 27, 2022 at 12:56:25PM +0100, Borislav Petkov wrote:
> From: Borislav Petkov <bp@xxxxxxx>
> 
> 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@xxxxxxx>
> Reviewed-by: Lai Jiangshan <jiangshanlai@xxxxxxxxx>

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@xxxxxxxxxxxx>

-- 
Kees Cook