Re: [PATCH v9 23/42] Documentation/x86: Add CET shadow stack description

The 07/05/2023 20:29, Mark Brown wrote:

On Wed, Jul 05, 2023 at 07:17:25PM +0000, Edgecombe, Rick P wrote:

quoted

Ah, interesting, thanks for the extra info. So which features is glibc
planning to use? (probably more of a question for Szabolcs). Are push
and pop controllable separately?

Push and pop are one control, you get both or neither.

I'll defer to Szabolcs on glibc plans.

gcspopm is always available (esentially *ssp++, this is used
for longjmp).

i haven't planned anything yet for other modes (i dont know
anything where writable shadow stack is better than just
turning the feature off, so i expect we at most have a
glibc tunable env var to enable it but it will not affect
glibc behaviour otherwise).