Re: [PATCH v7 00/11] add support for Clang's Shadow Call Stack

[Sami Tolvanen]

On Tue, Feb 11, 2020 at 5:57 AM James Morse <james.morse@xxxxxxx> wrote:
> I found I had to add:
> | KBUILD_CFLAGS := $(filter-out -ffixed-x18 $(CC_FLAGS_SCS), $(KBUILD_CFLAGS))
>
> to drivers/firmware/efi/libstub/Makefile, to get this going.

Ah, good catch!

> I don't think there is much point supporting SCS for the EFIstub, its already isolated
> from the rest of the kernel's C code by the __efistub symbol prefix machinery, and trying
> to use it would expose us to buggy firmware at a point we can't handle it!

Yes, fully agreed.

> I can send a patch if its easier for you,

It's not a problem, I will include a patch for this in v8.

Sami