[v2] raid6/altivec: Add vpermxor implementation for raid6 Q syndrome

[Michael Ellerman]

Daniel Axtens <dja at axtens.net> writes:

> Hi Matt,
>
> Thanks for answering my questions and doing those fixes.
>
>
>> Bugs fixed:
>> 	- A small bug in pq.h regarding a missing and mismatched
>> 	  ifdef statement
>> 	- Fixed test/Makefile to correctly build test on ppc
>>
>
> I think this commit should be labelled:
> Fixes: 4f8c55c5ad49 ("lib/raid6: build proper files on corresponding arch")
>
> mpe can probably add that when he merges - no need to do a new version :)

Please send a separate patch which does that fix.

>>  else
>> -        HAS_ALTIVEC := $(shell printf '\#include <altivec.h>\nvector int a;\n' |\
>> -                         gcc -c -x c - >&/dev/null && \
>> -                         rm ./-.o && echo yes)
>> -        ifeq ($(HAS_ALTIVEC),yes)
>> -                OBJS += altivec1.o altivec2.o altivec4.o altivec8.o
>> +	 HAS_ALTIVEC := $(shell printf '\#include <altivec.h>\nvector int a;\n' |\
>> +			 gcc -c -x c - >/dev/null && rm ./-.o && echo yes)
>> +	 ifeq ($(HAS_ALTIVEC),yes)
>> +		CFLAGS += -I../../../arch/powerpc/include
>> +		CFLAGS += -DCONFIG_ALTIVEC
>> +		OBJS += altivec1.o altivec2.o altivec4.o altivec8.o \
>> +			vpermxor1.o vpermxor2.o vpermxor4.o vpermxor8.o
>>          endif
>>  endif
> Looks like vim has replaced spaces with tabs here. Not sure how much we
> care...

We care at least because it makes the diff look bigger than it really
is, if I'm reading it right the first three lines haven't actually
changed.

>> @@ -97,6 +99,18 @@ altivec4.c: altivec.uc ../unroll.awk
>>  altivec8.c: altivec.uc ../unroll.awk
>>  	$(AWK) ../unroll.awk -vN=8 < altivec.uc > $@
>>
> ... especially seeing as tabs are already used in the file here!

It's a Makefile! Tabs have meaning :)

>> +# ifdef __KERNEL__
>> +	return (cpu_has_feature(CONFIG_ALTIVEC) &&
>> +		cpu_has_feature(CPU_FTR_ARCH_207S));
> I think CPU_FTR_ARCH_207S implies Altivec? Again, not a real problem,

It doesn't.

And also CONFIG_ALTIVEC is not a cpu feature!

You should be using CPU_FTR_ALTIVEC_COMP. That copes with the case where
the kernel is compiled without ALTIVEC support.

cheers