diff options
| author | Mark Rutland <mark.rutland@arm.com> | 2017-04-25 13:08:50 +0200 |
|---|---|---|
| committer | Catalin Marinas <catalin.marinas@arm.com> | 2017-04-25 16:12:59 +0200 |
| commit | faa9a08397f5034efad75b06879ac0ead83bd714 (patch) | |
| tree | cc6cfee64e98d9cd067e310334e279bb34067c68 /arch/arm64/kernel/perf_event.c | |
| parent | arm64: Add CNTFRQ_EL0 trap handler (diff) | |
| download | linux-faa9a08397f5034efad75b06879ac0ead83bd714.tar.xz linux-faa9a08397f5034efad75b06879ac0ead83bd714.zip | |
arm64: pmuv3: handle pmuv3+
Commit f1b36dcb5c316c27 ("arm64: pmuv3: handle !PMUv3 when probing") is
a little too restrictive, and prevents the use of of backwards
compatible PMUv3 extenstions, which have a PMUver value other than 1.
For instance, ARMv8.1 PMU extensions (as implemented by ThunderX2) are
reported with PMUver value 4.
Per the usual ID register principles, at least 0x1-0x7 imply a
PMUv3-compatible PMU. It's not currently clear whether 0x8-0xe imply the
same.
For the time being, treat the value as signed, and with 0x1-0x7 treated
as meaning PMUv3 is implemented. This may be relaxed by future patches.
Reported-by: Jayachandran C <jnair@caviumnetworks.com>
Tested-by: Jayachandran C <jnair@caviumnetworks.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Diffstat (limited to 'arch/arm64/kernel/perf_event.c')
| -rw-r--r-- | arch/arm64/kernel/perf_event.c | 7 |
1 files changed, 4 insertions, 3 deletions
diff --git a/arch/arm64/kernel/perf_event.c b/arch/arm64/kernel/perf_event.c index 98c749394c4b..5f64d19a3411 100644 --- a/arch/arm64/kernel/perf_event.c +++ b/arch/arm64/kernel/perf_event.c @@ -966,13 +966,14 @@ static void __armv8pmu_probe_pmu(void *info) { struct armv8pmu_probe_info *probe = info; struct arm_pmu *cpu_pmu = probe->pmu; - u64 dfr0, pmuver; + u64 dfr0; u32 pmceid[2]; + int pmuver; dfr0 = read_sysreg(id_aa64dfr0_el1); - pmuver = cpuid_feature_extract_unsigned_field(dfr0, + pmuver = cpuid_feature_extract_signed_field(dfr0, ID_AA64DFR0_PMUVER_SHIFT); - if (pmuver != 1) + if (pmuver < 1) return; probe->present = true; |