Re: [PATCH] powerpc: xor_vmx: Add '-mhard-float' to CFLAGS

[Nathan Chancellor <nathan@kernel.org>]

On Wed, Mar 06, 2024 at 12:01:42PM +1100, Michael Ellerman wrote:
> Nathan Chancellor <nathan@kernel.org> writes:
> > Ping? We have been applying this in our CI since it was sent, it would
> > be nice to have this upstream soon so it can start filtering through the
> > stable trees.
> 
> Sorry, I was away in January and missed this. Will pick it up.

No worries, I've done that more times than I would like to admit. Thanks
a lot for the quick response and picking it up!

Cheers,
Nathan

> > On Sat, Jan 27, 2024 at 11:07:43AM -0700, Nathan Chancellor wrote:
> >> arch/powerpc/lib/xor_vmx.o is built with '-msoft-float' (from the main
> >> powerpc Makefile) and '-maltivec' (from its CFLAGS), which causes an
> >> error when building with clang after a recent change in main:
> >> 
> >>   error: option '-msoft-float' cannot be specified with '-maltivec'
> >>   make[6]: *** [scripts/Makefile.build:243: arch/powerpc/lib/xor_vmx.o] Error 1
> >> 
> >> Explicitly add '-mhard-float' before '-maltivec' in xor_vmx.o's CFLAGS
> >> to override the previous inclusion of '-msoft-float' (as the last option
> >> wins), which matches how other areas of the kernel use '-maltivec', such
> >> as AMDGPU.
> >> 
> >> Cc: stable@vger.kernel.org
> >> Closes: https://github.com/ClangBuiltLinux/linux/issues/1986
> >> Link: https://github.com/llvm/llvm-project/commit/4792f912b232141ecba4cbae538873be3c28556c
> >> Signed-off-by: Nathan Chancellor <nathan@kernel.org>
> >> ---
> >>  arch/powerpc/lib/Makefile | 2 +-
> >>  1 file changed, 1 insertion(+), 1 deletion(-)
> >> 
> >> diff --git a/arch/powerpc/lib/Makefile b/arch/powerpc/lib/Makefile
> >> index 6eac63e79a89..0ab65eeb93ee 100644
> >> --- a/arch/powerpc/lib/Makefile
> >> +++ b/arch/powerpc/lib/Makefile
> >> @@ -76,7 +76,7 @@ obj-$(CONFIG_PPC_LIB_RHEAP) += rheap.o
> >>  obj-$(CONFIG_FTR_FIXUP_SELFTEST) += feature-fixups-test.o
> >>  
> >>  obj-$(CONFIG_ALTIVEC)	+= xor_vmx.o xor_vmx_glue.o
> >> -CFLAGS_xor_vmx.o += -maltivec $(call cc-option,-mabi=altivec)
> >> +CFLAGS_xor_vmx.o += -mhard-float -maltivec $(call cc-option,-mabi=altivec)
> >>  # Enable <altivec.h>
> >>  CFLAGS_xor_vmx.o += -isystem $(shell $(CC) -print-file-name=include)
> >>  
> >> 
> >> ---
> >> base-commit: 6613476e225e090cc9aad49be7fa504e290dd33d
> >> change-id: 20240127-ppc-xor_vmx-drop-msoft-float-ad68b437f86c
> >> 
> >> Best regards,
> >> -- 
> >> Nathan Chancellor <nathan@kernel.org>
> >> 
>