Re: [GIT PULL] core/hweight changes for v2.6.35

[Mike Frysinger]

On Fri, Aug 13, 2010 at 17:56, H. Peter Anvin wrote:
> On 08/13/2010 02:42 PM, Mike Frysinger wrote:
>> On Mon, May 17, 2010 at 17:21, Ingo Molnar wrote:
>>> Âarch/alpha/include/asm/bitops.h      Â|  18 +++++----
>>> Âarch/ia64/include/asm/bitops.h       |  11 +++--
>>> Âarch/sparc/include/asm/bitops_64.h     |  11 +++--
>>> Âarch/x86/include/asm/bitops.h       Â|  Â4 +-
>>> Âinclude/asm-generic/bitops/arch_hweight.h Â| Â 25 ++++++++++++
>>> Âinclude/asm-generic/bitops/const_hweight.h | Â 42 ++++++++++++++++++++
>>> Âinclude/asm-generic/bitops/hweight.h    |  Â8 +---
>>
>> did this miss Blackfin because the original patch was against the
>> 2.6.34 tree ? Âjust wondering why it now build fails ...
>>
>> doing a simple grep shows that the new "tile" arch may also be broken
>> as it uses "hweight32" ...
>>
>> considering __sw_hweightX only exist when the generic hweight is in
>> play, wouldnt it make sense to have
>> include/asm-generic/bitops/arch_hweight.h not always define things ?
>> then most arches can simply pull in
>> include/asm-generic/bitops/hweight.h without having to worry about the
>> random inner details of hweight cruft.
>>
>
> __sw_hweightX can exist even when generic hweight isn't in use per se,
> because the arch implementation can wrapper the software implementation.
> ÂThis is the case on x86, for example -- most x86 CPUs don't have popcnt
> yet, so on those the x86 implementation end up calling the
> __sw_hweight*() implementations.

but those targets still define CONFIG_GENERIC_HWEIGHT right ?  so at
the least, we should be wrapping the prototypes in linux/bitops.h with
that ...
-mike
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