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Re: [RFC] Expanding the hwcap


On Wed, 2012-10-17 at 23:42 -0500, Ryan Arnold wrote:
> On Wed, 2012-10-17 at 16:39 -0400, Mike Frysinger wrote:
> > sure.  my point was that we can keep a single hwcap in glibc itself and keep 
> > the hwcap.h macros the same.  the kernel will maintain a single 64bit value 
> > internally, take care of splitting it into two (AT_HWCAP & AT_HWCAP2), and 
> > glibc will take care of merging it back into one thus it only needs one hwcap 
> > value accessible via GLRO.
> 
> I'm not sure I understand the situation entirely from the kernel
> perspective, but I believe that the cpu_spec.cpu_user_features can't
> exceed 32-bits on PowerPC32 and to maintain parity with PowerPC64 we
> only use the low 32-bits there as well, hence the need for two fields in
> the kernel as well.

I don't see any reason why we can't make it a u64 and split it on the
way to userspace as Mike suggested.

Cheers,
Ben.



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