Re: [PATCH 1/3] powerpc: boot: include compiler_attributes.h

Nick Desaulniers [off-list ref] writes:

The kernel uses `-include` to include include/linux/compiler_types.h
into all translation units (see scripts/Makefile.lib), which #includes
compiler_attributes.h.

arch/powerpc/boot/ uses different compiler flags from the rest of the
kernel. As such, it doesn't contain the definitions from these headers,
and redefines a few that it needs.

For the purpose of enabling -Wimplicit-fallthrough for ppc, include
compiler_types.h via `-include`.

Link: https://github.com/ClangBuiltLinux/linux/issues/236
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
---
We could just `#include "include/linux/compiler_types.h"` in the few .c
sources used from lib/ (there are proper header guards in
compiler_types.h).

It was also noted in 6a9dc5fd6170 that we could -D__KERNEL__ and
-include compiler_types.h like the main kernel does, though testing that
produces a whole sea of warnings to cleanup. This approach is minimally
invasive.

 arch/powerpc/boot/Makefile     | 1 +
 arch/powerpc/boot/decompress.c | 1 -
 2 files changed, 1 insertion(+), 1 deletion(-)

Acked-by: Michael Ellerman <mpe@ellerman.id.au>

cheers