| Message ID | 20210913081424.48613-4-vincenzo.frascino@arm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | arm64: ARMv8.7-A: MTE: Add asymm mode support | expand |
On Mon, Sep 13, 2021 at 09:14:22AM +0100, Vincenzo Frascino wrote: > diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c > index f8a3067d10c6..a18774071a45 100644 > --- a/arch/arm64/kernel/cpufeature.c > +++ b/arch/arm64/kernel/cpufeature.c > @@ -2317,6 +2317,16 @@ static const struct arm64_cpu_capabilities arm64_features[] = { > .sign = FTR_UNSIGNED, > .cpu_enable = cpu_enable_mte, > }, > + { > + .desc = "Asymmetric Memory Tagging Extension", I'd give this a better name as it's not entirely clear what it does. In the ARM ARM this is described as "asymmetric Tag Check Fault handling". Maybe just rename it to "Asymmetric MTE Tag Check Fault". Similarly in the Kconfig if you added one. Otherwise: Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
On 13/09/2021 09:14, Vincenzo Frascino wrote: > Add the cpufeature entries to detect the presence of Asymmetric MTE. > > Note: The tag checking mode is initialized via cpu_enable_mte() -> > kasan_init_hw_tags() hence to enable it we require asymmetric mode > to be at least on the boot CPU. If the boot CPU does not have it, it is > fine for late CPUs to have it as long as the feature is not enabled > (ARM64_CPUCAP_BOOT_CPU_FEATURE). > > Cc: Will Deacon <will@kernel.org> > Cc: Catalin Marinas <catalin.marinas@arm.com> > Cc: Suzuki K Poulose <Suzuki.Poulose@arm.com> > Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com> > --- > arch/arm64/kernel/cpufeature.c | 10 ++++++++++ > arch/arm64/tools/cpucaps | 1 + > 2 files changed, 11 insertions(+) > > diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c > index f8a3067d10c6..a18774071a45 100644 > --- a/arch/arm64/kernel/cpufeature.c > +++ b/arch/arm64/kernel/cpufeature.c > @@ -2317,6 +2317,16 @@ static const struct arm64_cpu_capabilities arm64_features[] = { > .sign = FTR_UNSIGNED, > .cpu_enable = cpu_enable_mte, > }, > + { > + .desc = "Asymmetric Memory Tagging Extension", > + .capability = ARM64_MTE_ASYMM, > + .type = ARM64_CPUCAP_BOOT_CPU_FEATURE, FWIW, the selected type works for the described use case. Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com> > + .matches = has_cpuid_feature, > + .sys_reg = SYS_ID_AA64PFR1_EL1, > + .field_pos = ID_AA64PFR1_MTE_SHIFT, > + .min_field_value = ID_AA64PFR1_MTE_ASYMM, > + .sign = FTR_UNSIGNED, > + }, > #endif /* CONFIG_ARM64_MTE */ > { > .desc = "RCpc load-acquire (LDAPR)", > diff --git a/arch/arm64/tools/cpucaps b/arch/arm64/tools/cpucaps > index 49305c2e6dfd..74a569bf52d6 100644 > --- a/arch/arm64/tools/cpucaps > +++ b/arch/arm64/tools/cpucaps > @@ -39,6 +39,7 @@ HW_DBM > KVM_PROTECTED_MODE > MISMATCHED_CACHE_TYPE > MTE > +MTE_ASYMM > SPECTRE_V2 > SPECTRE_V3A > SPECTRE_V4 >
diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c index f8a3067d10c6..a18774071a45 100644 --- a/arch/arm64/kernel/cpufeature.c +++ b/arch/arm64/kernel/cpufeature.c @@ -2317,6 +2317,16 @@ static const struct arm64_cpu_capabilities arm64_features[] = { .sign = FTR_UNSIGNED, .cpu_enable = cpu_enable_mte, }, + { + .desc = "Asymmetric Memory Tagging Extension", + .capability = ARM64_MTE_ASYMM, + .type = ARM64_CPUCAP_BOOT_CPU_FEATURE, + .matches = has_cpuid_feature, + .sys_reg = SYS_ID_AA64PFR1_EL1, + .field_pos = ID_AA64PFR1_MTE_SHIFT, + .min_field_value = ID_AA64PFR1_MTE_ASYMM, + .sign = FTR_UNSIGNED, + }, #endif /* CONFIG_ARM64_MTE */ { .desc = "RCpc load-acquire (LDAPR)", diff --git a/arch/arm64/tools/cpucaps b/arch/arm64/tools/cpucaps index 49305c2e6dfd..74a569bf52d6 100644 --- a/arch/arm64/tools/cpucaps +++ b/arch/arm64/tools/cpucaps @@ -39,6 +39,7 @@ HW_DBM KVM_PROTECTED_MODE MISMATCHED_CACHE_TYPE MTE +MTE_ASYMM SPECTRE_V2 SPECTRE_V3A SPECTRE_V4
Add the cpufeature entries to detect the presence of Asymmetric MTE. Note: The tag checking mode is initialized via cpu_enable_mte() -> kasan_init_hw_tags() hence to enable it we require asymmetric mode to be at least on the boot CPU. If the boot CPU does not have it, it is fine for late CPUs to have it as long as the feature is not enabled (ARM64_CPUCAP_BOOT_CPU_FEATURE). Cc: Will Deacon <will@kernel.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Suzuki K Poulose <Suzuki.Poulose@arm.com> Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com> --- arch/arm64/kernel/cpufeature.c | 10 ++++++++++ arch/arm64/tools/cpucaps | 1 + 2 files changed, 11 insertions(+)