# Re: \[PATCH v8 18/40\] mm: Introduce VM\_SHADOW\_STACK for shadow stack memory

- From: David Hildenbrand \<hidden\>
- Date: 2023-03-20 11:02:00 
- List: linux-api
- Page: https://ratatoskr.run/linux-api/2023/03/2140184
- Thread: https://ratatoskr.run/linux-doc/2023/03/2138992/t.md

```text
On 19.03.23 01:15, Rick Edgecombe wrote:
> From: Yu-cheng Yu <redacted>
>
> New hardware extensions implement support for shadow stack memory, such
> as x86 Control-flow Enforcement Technology (CET). Add a new VM flag to
> identify these areas, for example, to be used to properly indicate shadow
> stack PTEs to the hardware.
>
> Shadow stack VMA creation will be tightly controlled and limited to
> anonymous memory to make the implementation simpler and since that is all
> that is required. The solution will rely on pte_mkwrite() to create the
> shadow stack PTEs, so it will not be required for vm_get_page_prot() to
> learn how to create shadow stack memory. For this reason document that
> VM_SHADOW_STACK should not be mixed with VM_SHARED.
>
> Co-developed-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
> Signed-off-by: Yu-cheng Yu <redacted>
> Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
> Reviewed-by: Kees Cook <redacted>
> Reviewed-by: Kirill A. Shutemov <redacted>
> Acked-by: Mike Rapoport (IBM) <rppt@kernel.org>
> Tested-by: Pengfei Xu <redacted>
> Tested-by: John Allen <redacted>
> Tested-by: Kees Cook <redacted>
> ---

Acked-by: David Hildenbrand <redacted>

-- 
Thanks,

David / dhildenb

```