Oliver Upton oliver.upton@linux.dev writes:
On Mon, Jun 23, 2025 at 06:25:38PM +0000, Colton Lewis wrote:
Oliver Upton oliver.upton@linux.dev writes:
On Fri, Jun 20, 2025 at 10:13:01PM +0000, Colton Lewis wrote:
Add a capability for FEAT_HPMN0, whether MDCR_EL2.HPMN can specify 0 counters reserved for the guest.
This required changing HPMN0 to an UnsignedEnum in tools/sysreg because otherwise not all the appropriate macros are generated to add it to arm64_cpu_capabilities_arm64_features.
Signed-off-by: Colton Lewis coltonlewis@google.com
arch/arm64/kernel/cpufeature.c | 8 ++++++++ arch/arm64/tools/cpucaps | 1 + arch/arm64/tools/sysreg | 6 +++--- 3 files changed, 12 insertions(+), 3 deletions(-)
diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c index b34044e20128..278294fdc97d 100644 --- a/arch/arm64/kernel/cpufeature.c +++ b/arch/arm64/kernel/cpufeature.c @@ -548,6 +548,7 @@ static const struct arm64_ftr_bits
ftr_id_mmfr0[] = {
};
static const struct arm64_ftr_bits ftr_id_aa64dfr0[] = {
- ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE,
ID_AA64DFR0_EL1_HPMN0_SHIFT, 4, 0), S_ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64DFR0_EL1_DoubleLock_SHIFT, 4, 0), ARM64_FTR_BITS(FTR_HIDDEN, FTR_NONSTRICT, FTR_LOWER_SAFE, ID_AA64DFR0_EL1_PMSVer_SHIFT, 4, 0), ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64DFR0_EL1_CTX_CMPs_SHIFT, 4, 0), @@ -2896,6 +2897,13 @@ static const struct arm64_cpu_capabilities arm64_features[] = { .matches = has_cpuid_feature, ARM64_CPUID_FIELDS(ID_AA64MMFR0_EL1, FGT, FGT2) },
- {
.desc = "Allow MDCR_EL2.HPMN = 0",
This feedback still stands...
.desc = "HPMN0",
Sorry for ignoring your previous feedback. I looked at the other .desc fields and they had more descriptive English, so I think this one should be more than "FEAT_HPMN0" for consistency.
If you insist I'll change it.
I'm not exactly sold on the merits of using descriptive names for the capabilities, as the architecture extension names are exact terms that can be related back to documentation.
I'll change it.