Re: [PATCH] powerpc: Fix TLE build for SPE (BZ #22926)

[Adhemerval Zanella <adhemerval.zanella@linaro.org>]

On 06/03/2018 15:37, Adhemerval Zanella wrote:
> 
> 
> On 05/03/2018 15:17, Adhemerval Zanella wrote:
>> Some SPE opcodes clashes with some recent PowerISA opcodes and
>> until recently gas did not complain about it.  However binutils
>> recently changed it and now VLE configured gas does not support to
>> assembler some instruction that might class with VLE (HTM for
>> instance).  It also does not help that glibc build hardware lock
>> elision support as default (regardless of assembler support).
>>
>> Although runtime will not actually enables TLE on SPE hardware
>> (since kernel will not advertise it), I see little advantage on
>> adding HTM support on SPE built glibc.  SPE uses an incompatible
>> ABI which does not allow share the same build with default
>> powerpc and HTM code slows down SPE without any benefict.
>>
>> This patch fixes it by only building HTM when SPE configuration
>> is not used.
>>
>> Checked with a powerpc-linux-gnuspe build. I also did some sniff
>> tests on a e500 hardware without any issue.
> 
> I also saw no regression compared to PowerPC (32-bit soft-float) report
> for 2.27 [1] on a e500 hardware.
> 
> [1] https://sourceware.org/glibc/wiki/Release/2.27#PowerPC_.2832-bit_soft-float.29
> 

If no one opposes I will commit it this shortly.