Re: [PATCH] [PATCH v2] AARCH64: Add gcc Shadow Call Stack support

[Nick Desaulniers]

On Mon, Feb 28, 2022 at 4:32 PM Dan Li <ashimida@xxxxxxxxxxxxxxxxx> wrote:
>
>
>
> On 2/28/22 14:35, Nick Desaulniers wrote:
> > On Sun, Feb 27, 2022 at 11:37 PM Dan Li <ashimida@xxxxxxxxxxxxxxxxx> wrote:
> >>>> +#ifdef CONFIG_SHADOW_CALL_STACK
> >>>> +#define __noscs __attribute__((__no_sanitize__("shadow-call-stack")))
> >>>> +#endif
> >>>
> >>> Since both compilers have it, and I guess the `#ifdef` condition would
> >>> work for both, could this be moved into `compiler_types.h` where the
> >>> empty `__noscs` definition is, and remove the one from
> >>> `compiler-clang.h`?
> >>>
> >> In the clang documentation I see __has_feature(shadow_call_stack) is
> >> used to check if -fsanitize=shadow-call-stack is enabled, so I think
> >> maybe it's fine to use "#ifdef CONFIG_SHADOW_CALL_STACK"
> >> instead of "#if __has_attribute(__no_sanitize_address__)" here, then
> >> move it to `compiler_types.h`.
> >
> > Or simply add a #define for __noscs to include/linux/compiler-gcc.h
> > with appropriate guard and leave the existing #ifndef in
> > include/linux/compiler_types.h as is.  I'd prefer that when the
> > compilers differ in terms of feature detection since it's as explicit
> > as possible.
> >
>
> To make sure I understand correctly, that means I should keep
> the current patch unchanged right?

Yes.
Reviewed-by: Nick Desaulniers <ndesaulniers@xxxxxxxxxx>
-- 
Thanks,
~Nick Desaulniers