Re: [PATCH v2 0/2] sparc/build: Rework CFLAGS for clang compatibility

[Nathan Chancellor <nathan@kernel.org>]

Hi Andreas,

On Wed, Jul 17, 2024 at 11:10:14PM +0700, Koakuma wrote:
> This changes the CFLAGS for building the SPARC kernel so that it can be
> built with clang, as a follow up from the discussion in this thread:
> 
> https://lore.kernel.org/lkml/JAYB7uS-EdLABTR4iWZdtFOVa5MvlKosIrD_cKTzgeozCOGRM7lhxeLigFB1g3exX445I_W5VKB-tAzl2_G1zCVJRQjp67ODfsSqiZWOZ9o=@protonmail.com/T/#u
...
> Building with these changes still result in a working kernel,
> at least for Sun T5120, Oracle T4-1, and qemu virtual machines.
> 
> On the LLVM side, the effort for building Linux/SPARC is tracked here:
> https://github.com/llvm/llvm-project/issues/40792
> 
> Signed-off-by: Koakuma <koachan@protonmail.com>
> ---
> Changes in v2:
> - Remove the -mv8plus change; it will be handled on clang side:
>   https://github.com/llvm/llvm-project/pull/98713
> - Add CLANG_TARGET_FLAGS as suggested in v1 review.
> - Link to v1: https://lore.kernel.org/r/20240620-sparc-cflags-v1-1-bba7d0ff7d42@protonmail.com
> 
> ---
> Koakuma (2):
>       sparc/build: Remove all usage of -fcall-used* flags
>       sparc/build: Add SPARC target flags for compiling with clang
> 
>  arch/sparc/Makefile      | 4 ++--
>  arch/sparc/vdso/Makefile | 2 +-
>  scripts/Makefile.clang   | 1 +
>  3 files changed, 4 insertions(+), 3 deletions(-)

Would you be able to help move this series [1] and its companion patch
for the vDSO [2] along to Linus for 6.13? If you are not able to for
whatever reason but the changes look reasonable to you, would you be
able to provide an Ack so it can be chauffeured by someone else, such as
Masahiro/Kbuild or Andrew/-mm?

For the record, I retested these three changes on top of 6.12-rc4, where
they still apply cleanly. Now that the LLVM PR linked above (98713) has
been merged into LLVM main, a clang built straight from llvm-project.git
can build the kernel with this series (I tested at dca43a1c82f1).

[1]: https://lore.kernel.org/all/20240717-sparc-cflags-v2-0-259407e6eb5f@protonmail.com/
[2]: https://lore.kernel.org/all/20240808-sparc-shr64-v2-1-fd18f1b2cea9@protonmail.com/

Cheers,
Nathan