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

[Edgecombe, Rick P]

On Tue, 2023-06-13 at 18:57 +0100, Mark Brown wrote:
> > > > For my part, the thing I would really like to see unified as
> > > > much > > as
> > > > possible is at the app developer's interface (glibc/gcc). The
> > > > idea
> > > > would be to make it easy for app developers to know if their
> > > > app
> > > > supports shadow stack. There will probably be some differences,
> > > > but > > it
> > > > would be great if there was mostly the same behavior and a
> > > > small > > list
> > > > of differences. I'm thinking about the behavior of longjmp(),
> > > > swapcontext(), etc.
> > 
> > Yes, very much so.  sigaltcontext() too.

For alt shadow stack's, this is what I came up with:
https://lore.kernel.org/lkml/20220929222936.14584-40-rick.p.edgecombe@xxxxxxxxx/

Unfortunately it can't work automatically with sigaltstack(). Since it
has to be a new thing anyway, it's been left for the future. I guess
that might have a better chance of being cross arch.


BTW, last time this series accidentally broke an arm config and made it
all the way through the robots up to Linus. Would you mind giving
patches 1-3 a check?

Thanks,

Rick