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

From: Michael Ellerman <[email-masked]>
Date: Wed, 06 Mar 2024 12:01:42 +1100

Nathan Chancellor <[email-masked]> 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.

cheers

> 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: [email-masked]
>> Closes: https://github.com/ClangBuiltLinux/linux/issues/1986
>> Link: https://github.com/llvm/llvm-project/commit/4792f912b232141ecba4cbae538873be3c28556c
>> Signed-off-by: Nathan Chancellor <[email-masked]>
>> ---
>>  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 <[email-masked]>
>>