On Wed, May 23, 2018 at 09:48:28AM +0100, Suzuki K Poulose wrote: > > Mark, > > On 03/05/18 14:20, Mark Rutland wrote: > > So that we can dynamically handle the presence of pointer authentication > > functionality, wire up probing code in cpufeature.c. > > > > From ARMv8.3 onwards, ID_AA64ISAR1 is no longer entirely RES0, and now > > has four fields describing the presence of pointer authentication > > functionality: > > > > * APA - address authentication present, using an architected algorithm > > * API - address authentication present, using an IMP DEF algorithm > > * GPA - generic authentication present, using an architected algorithm > > * GPI - generic authentication present, using an IMP DEF algorithm > > > > For the moment we only care about address authentication, so we only > > need to check APA and API. It is assumed that if all CPUs support an IMP > > DEF algorithm, the same algorithm is used across all CPUs. > > > > Note that when we implement KVM support, we will also need to ensure > > that CPUs have uniform support for GPA and GPI. > > > > Signed-off-by: Mark Rutland <mark.rutland@xxxxxxx> > > Cc: Catalin Marinas <catalin.marinas@xxxxxxx> > > Cc: Suzuki K Poulose <suzuki.poulose@xxxxxxx> > > Cc: Will Deacon <will.deacon@xxxxxxx> > > --- > > arch/arm64/include/asm/cpucaps.h | 5 ++++- > > arch/arm64/kernel/cpufeature.c | 47 ++++++++++++++++++++++++++++++++++++++++ > > 2 files changed, 51 insertions(+), 1 deletion(-) > > > > diff --git a/arch/arm64/include/asm/cpucaps.h b/arch/arm64/include/asm/cpucaps.h > > index bc51b72fafd4..9dcb4d1b14f5 100644 > > --- a/arch/arm64/include/asm/cpucaps.h > > +++ b/arch/arm64/include/asm/cpucaps.h > > @@ -48,7 +48,10 @@ > > #define ARM64_HAS_CACHE_IDC 27 > > #define ARM64_HAS_CACHE_DIC 28 > > #define ARM64_HW_DBM 29 > > +#define ARM64_HAS_ADDRESS_AUTH_ARCH 30 > > +#define ARM64_HAS_ADDRESS_AUTH_IMP_DEF 31 > > Where are these caps used ? I couldn't find anything in the series > that uses them. Otherwise looks good to me. Those were consumed by KVM support, which needed to detect if CPUs had mismatched support. Currently they're just placeholders as I need a cpucap value for the separate IMP-DEF / architected probing cases. I *could* get rid of those and just have the ARM64_HAS_ADDRESS_AUTH case log "Address authentication", but I wanted to have separate messages for IMP-DEF vs architected. Thanks, Mark. _______________________________________________ kvmarm mailing list kvmarm@xxxxxxxxxxxxxxxxxxxxx https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
