Re: [PATCH RFC RFT v2 1/5] mm: Introduce ARCH_HAS_USER_SHADOW_STACK

Mark Brown
2023-11-15T14:55:16Z

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On Tue, Nov 14, 2023 at 11:22:16PM +0000, Edgecombe, Rick P wrote:
> On Tue, 2023-11-14 at 20:05 +0000, Mark Brown wrote:
> > +config ARCH_HAS_USER_SHADOW_STACK
> > +       bool
> > +       help
> > +         The architecture has hardware support for userspace shadow
> > call
> > +          stacks (eg, x86 CET, arm64 GCS, RISC-V Zisslpcfi).

> I feel like normally a patch like this should come with the second
> feature that gets enabled. (i.e. arm or riscv). Especially since the
> comment lists currently unsupported features. I think something like
> this got nixed by an x86 maintainer earlier, but that was before these
> other features were getting pushed.

> I don't have a strong objection to having it ahead of the other
> features though and it is nice to remove X86 defines out of core code.

Given that the GCS patches are on the list and relatively
uncontroversial it does seem reasonable to carry this - I'm only able to
test this in the context of having both serieses applied!

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