Re: [PATCH] powerpc/uaccess: Perform barrier_nospec() in KUAP allowance helpers

From: Michael Ellerman
Date: Wed Feb 10 2021 - 08:03:16 EST


On Sun, 7 Feb 2021 10:08:11 +0000 (UTC), Christophe Leroy wrote:
> barrier_nospec() in uaccess helpers is there to protect against
> speculative accesses around access_ok().
>
> When using user_access_begin() sequences together with
> unsafe_get_user() like macros, barrier_nospec() is called for
> every single read although we know the access_ok() is done
> onece.
>
> [...]

Applied to powerpc/next.

[1/1] powerpc/uaccess: Perform barrier_nospec() in KUAP allowance helpers
https://git.kernel.org/powerpc/c/8524e2e76441fc615a3b5c1415823e051cc79eae

cheers