[PATCH 2/4] arm64: cpufeature: add feature for CRC32 instructions

Herbert Xu herbert at gondor.apana.org.au
Mon Sep 3 20:18:55 PDT 2018


On Tue, Aug 28, 2018 at 08:43:35PM +0200, Ard Biesheuvel wrote:
> On 28 August 2018 at 19:01, Will Deacon <will.deacon at arm.com> wrote:
> > On Mon, Aug 27, 2018 at 01:02:43PM +0200, Ard Biesheuvel wrote:
> >> Add a CRC32 feature bit and wire it up to the CPU id register so we
> >> will be able to use alternatives patching for CRC32 operations.
> >>
> >> Signed-off-by: Ard Biesheuvel <ard.biesheuvel at linaro.org>
> >> ---
> >>  arch/arm64/include/asm/cpucaps.h | 3 ++-
> >>  arch/arm64/kernel/cpufeature.c   | 9 +++++++++
> >>  2 files changed, 11 insertions(+), 1 deletion(-)
> >
> > Acked-by: Will Deacon <will.deacon at arm.com>
> >
> > With the minor caveat below...
> >
> >> diff --git a/arch/arm64/include/asm/cpucaps.h b/arch/arm64/include/asm/cpucaps.h
> >> index ae1f70450fb2..9932aca9704b 100644
> >> --- a/arch/arm64/include/asm/cpucaps.h
> >> +++ b/arch/arm64/include/asm/cpucaps.h
> >> @@ -51,7 +51,8 @@
> >>  #define ARM64_SSBD                           30
> >>  #define ARM64_MISMATCHED_CACHE_TYPE          31
> >>  #define ARM64_HAS_STAGE2_FWB                 32
> >> +#define ARM64_HAS_CRC32                              33
> >>
> >> -#define ARM64_NCAPS                          33
> >> +#define ARM64_NCAPS                          34
> >
> >
> > ... if this goes via crypto, you'll almost certainly get a (trivial)
> > conflict with arm64, since these numbers get bumped all the time.
> >
> 
> I think the first three patches should go through the arm64 tree. The
> last one just removes the now redundant crc32 SIMD driver, and Herbert
> could pick that up separately, i.e., it should be totally independent.

Yes let's do that.

Thanks,
-- 
Email: Herbert Xu <herbert at gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt



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