Re: [PATCH v15 05/26] x86/cet/shstk: Add Kconfig option for user-mode Shadow Stack

Yu, Yu-cheng
2020-11-30T20:31:24Z

On 11/30/2020 11:56 AM, Nick Desaulniers wrote:
> In response to https://lore.kernel.org/lkml/20201110162211.9207-6-yu-cheng.yu@intel.com/.
>
> Hi Yu-cheng,
> This feature reminds me very much of
> ARCH_SUPPORTS_SHADOW_CALL_STACK/CC_HAVE_SHADOW_CALL_STACK implemented in
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=5287569a790d2546a06db07e391bf84b8bd6cf51.
>
> Do you think it would be worthwhile to share the same config name between x86
> and aarch64?

The CET series has ARCH_HAS_SHADOW_STACK. In response to Boris' earlier
comment, I think this maybe eliminated. In case it is still needed, I
think it is better to have different names (but I am open to changing it).

>
> (Though, it seems on x86 there will be a distinction between kernel mode and
> user mode configs, if I understand correctly?)
>

Yes, on x86, kernel and user-mode can be enabled separately.

Yu-cheng