On Mon, Apr 01, 2019 at 11:45:14AM +0100, Andrew Murray wrote: > Advertise ARM64_HAS_DCPOP when both DC CVAP and DC CVADP are supported. Do you mean ARM64_HAS_DCPODP? And do we need this? This capability flag doesn't currently appear to be used for anything (which makes me wonder whether it _should_ be wired up to something in the kernel). Do we expect the kernel to do something special with this in the future? OTOH, we get a nice printk when the feature is detected, and the code size cost is insignificant. So, if there's a reasonable expectation that we will use it someday, I don't see a big problem with having it. Cheers ---Dave > > Signed-off-by: Andrew Murray <andrew.murray@xxxxxxx> > --- > arch/arm64/include/asm/cpucaps.h | 3 ++- > arch/arm64/kernel/cpufeature.c | 9 +++++++++ > 2 files changed, 11 insertions(+), 1 deletion(-) > > diff --git a/arch/arm64/include/asm/cpucaps.h b/arch/arm64/include/asm/cpucaps.h > index f6a76e43f39e..defdc67d9ab4 100644 > --- a/arch/arm64/include/asm/cpucaps.h > +++ b/arch/arm64/include/asm/cpucaps.h > @@ -61,7 +61,8 @@ > #define ARM64_HAS_GENERIC_AUTH_ARCH 40 > #define ARM64_HAS_GENERIC_AUTH_IMP_DEF 41 > #define ARM64_HAS_IRQ_PRIO_MASKING 42 > +#define ARM64_HAS_DCPODP 43 > > -#define ARM64_NCAPS 43 > +#define ARM64_NCAPS 44 > > #endif /* __ASM_CPUCAPS_H */ > diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c > index 5e27d2dbe45e..c74b25895c43 100644 > --- a/arch/arm64/kernel/cpufeature.c > +++ b/arch/arm64/kernel/cpufeature.c > @@ -1339,6 +1339,15 @@ static const struct arm64_cpu_capabilities arm64_features[] = { > .field_pos = ID_AA64ISAR1_DPB_SHIFT, > .min_field_value = 1, > }, > + { > + .desc = "Data cache clean to Point of Deep Persistence", > + .capability = ARM64_HAS_DCPODP, > + .type = ARM64_CPUCAP_SYSTEM_FEATURE, > + .matches = has_cpuid_feature, > + .sys_reg = SYS_ID_AA64ISAR1_EL1, > + .field_pos = ID_AA64ISAR1_DPB_SHIFT, > + .min_field_value = 2, > + }, > #endif > #ifdef CONFIG_ARM64_SVE > { > -- > 2.21.0 >