Re: [PATCHv6] powerpc: Add hwcap/hwcap2/platform data to TCB

[Carlos Eduardo Seo <cseo at linux dot vnet dot ibm dot com>]

Thanks for the review.

> On Oct 27, 2015, at 11:18 PM, Carlos O'Donell <carlos@redhat.com> wrote:
> 
> Looking really good.
> 
> (a) Use of uint64_t vs. casting.
> 
> How much slower is uin64_t vs. casting?
> 
> The call to __tcb_parse_hwcap_and_convert_at_platform is
> in the fast path for process startup. So any code we add
> counts, and this is the kind of thing where add a little
> bit at a time until the startup is slower than we wanted.
> 
> So if Peter says uint64_t is slow, we should listen and
> make that faster.
> 

Okay, I understand.

> (b) Unique HWCAP and HWCAP2 offsets in TCB.
> 
> I have no opinion. You and Peter need to resolve this
> and ensure gcc operates as expected.

I agree with Steve here and I think a single hwcap is a better option.

> 
> In summary:
> 
> If you fix (a), and the ChangeLog, then it's good for me.

Will do. Thanks for clarifying.

-- 
Carlos Eduardo Seo
Software Engineer - Linux on Power Toolchain
cseo@linux.vnet.ibm.com