Re: [PATCH 1/2] MIPS: Makefile: Set correct ISA level for MIPS ASEs

[Markos Chandras <Markos.Chandras@imgtec.com>]

On 01/30/2015 04:50 PM, Maciej W. Rozycki wrote:
> On Fri, 30 Jan 2015, Markos Chandras wrote:
> 
>>>>  cflags-$(CONFIG_SB1XXX_CORELIS)	+= $(call cc-option,-mno-sched-prolog) \
>>>>  				   -fno-omit-frame-pointer
>>>>  
>>>>  ifeq ($(CONFIG_CPU_HAS_MSA),y)
>>>> -toolchain-msa	:= $(call cc-option-yn,-mhard-float -mfp64
>> -Wa$(comma)-mmsa)
>>>> +toolchain-msa	:= $(call cc-option-yn,-march=mips32r2 -mhard-float
>> -mfp64 -Wa$(comma)-mmsa)
>>>>  cflags-$(toolchain-msa)		+= -DTOOLCHAIN_SUPPORTS_MSA
>>>>  endif
>>>
>>>  Similarly here, is CPU_HAS_MSA incompatible with `-march=mips64r2'?
>> I am not sure but like I explained above, it does not have to be 100%
>> accurate. Just something to keep your toolchain happy and really enable
>> MSA support even if you happen and old ISA level as the default one for
>> your toolchain.
>>
>> for example, if your toolchain has -march=mips2 as default then
>>
>> -mhard-float -mfp64 will fail
>>
>> but
>>
>> -march=mips32r2 -mhard-float -mfp64
>>
>> will pass. Your toolchain does support MSA, but because you combined the
>> check with incompatible flags, then the end result is not what you want.
> 
>  Hmm doesn't `cc-option-yn' pull options accumulated in $(cflags-y) 
> already for the check it makes?  If not, then it's rather less than useful 
> for us and I can see two options here:

I think it does but IIRC at this point no -march=XXXX was set. Perhaps
moving the ASEs checks after the CPU_* code in Makefile to fix this
problem indirectly.

-- 
markos