Re: [PATCH v10 12/12] efi/libstub: disable SCS

[Ard Biesheuvel]

On Mon, 6 Apr 2020 at 18:42, Sami Tolvanen <samitolvanen@xxxxxxxxxx> wrote:
>
> Shadow stacks are not available in the EFI stub, filter out SCS flags.
>
> Suggested-by: James Morse <james.morse@xxxxxxx>
> Signed-off-by: Sami Tolvanen <samitolvanen@xxxxxxxxxx>

Acked-by: Ard Biesheuvel <ardb@xxxxxxxxxx>

> ---
>  drivers/firmware/efi/libstub/Makefile | 3 +++
>  1 file changed, 3 insertions(+)
>
> diff --git a/drivers/firmware/efi/libstub/Makefile b/drivers/firmware/efi/libstub/Makefile
> index 094eabdecfe6..fa0bb64f93d6 100644
> --- a/drivers/firmware/efi/libstub/Makefile
> +++ b/drivers/firmware/efi/libstub/Makefile
> @@ -32,6 +32,9 @@ KBUILD_CFLAGS                 := $(cflags-y) -DDISABLE_BRANCH_PROFILING \
>                                    $(call cc-option,-fno-stack-protector) \
>                                    -D__DISABLE_EXPORTS
>
> +#  remove SCS flags from all objects in this directory
> +KBUILD_CFLAGS := $(filter-out $(CC_FLAGS_SCS), $(KBUILD_CFLAGS))
> +
>  GCOV_PROFILE                   := n
>  KASAN_SANITIZE                 := n
>  UBSAN_SANITIZE                 := n
> --
> 2.26.0.292.g33ef6b2f38-goog
>