Re: [PATCH v13 01/12] add support for Clang's Shadow Call Stack (SCS)

[Miguel Ojeda]

On Mon, Apr 27, 2020 at 6:00 PM Sami Tolvanen <samitolvanen@xxxxxxxxxx> wrote:
>
> diff --git a/include/linux/compiler-clang.h b/include/linux/compiler-clang.h
> index 333a6695a918..18fc4d29ef27 100644
> --- a/include/linux/compiler-clang.h
> +++ b/include/linux/compiler-clang.h
> @@ -42,3 +42,9 @@
>   * compilers, like ICC.
>   */
>  #define barrier() __asm__ __volatile__("" : : : "memory")
> +
> +#if __has_feature(shadow_call_stack)
> +# define __noscs       __attribute__((__no_sanitize__("shadow-call-stack")))
> +#else
> +# define __noscs
> +#endif

Can we remove the `#else` branch? compiler_types.h [*] has to care
anyway about that case for other compilers anyway, no?

> diff --git a/include/linux/compiler_types.h b/include/linux/compiler_types.h
> index e970f97a7fcb..97b62f47a80d 100644
> --- a/include/linux/compiler_types.h
> +++ b/include/linux/compiler_types.h
> @@ -193,6 +193,10 @@ struct ftrace_likely_data {
>  # define randomized_struct_fields_end
>  #endif
>
> +#ifndef __noscs
> +# define __noscs
> +#endif

[*] Here

Cheers,
Miguel