diff options
Diffstat (limited to 'arch/arm64/kernel/perf_event.c')
| -rw-r--r-- | arch/arm64/kernel/perf_event.c | 21 |
1 files changed, 16 insertions, 5 deletions
diff --git a/arch/arm64/kernel/perf_event.c b/arch/arm64/kernel/perf_event.c index ab504f72bc63..1cb61c9fbb21 100644 --- a/arch/arm64/kernel/perf_event.c +++ b/arch/arm64/kernel/perf_event.c @@ -405,6 +405,7 @@ static const struct attribute_group *armv8_pmuv3_attr_groups[] = { #define ARMV8_PMCR_D (1 << 3) /* CCNT counts every 64th cpu cycle */ #define ARMV8_PMCR_X (1 << 4) /* Export to ETM */ #define ARMV8_PMCR_DP (1 << 5) /* Disable CCNT if non-invasive debug*/ +#define ARMV8_PMCR_LC (1 << 6) /* Overflow on 64 bit cycle counter */ #define ARMV8_PMCR_N_SHIFT 11 /* Number of counters supported */ #define ARMV8_PMCR_N_MASK 0x1f #define ARMV8_PMCR_MASK 0x3f /* Mask for writable bits */ @@ -494,9 +495,16 @@ static inline void armv8pmu_write_counter(struct perf_event *event, u32 value) if (!armv8pmu_counter_valid(cpu_pmu, idx)) pr_err("CPU%u writing wrong counter %d\n", smp_processor_id(), idx); - else if (idx == ARMV8_IDX_CYCLE_COUNTER) - asm volatile("msr pmccntr_el0, %0" :: "r" (value)); - else if (armv8pmu_select_counter(idx) == idx) + else if (idx == ARMV8_IDX_CYCLE_COUNTER) { + /* + * Set the upper 32bits as this is a 64bit counter but we only + * count using the lower 32bits and we want an interrupt when + * it overflows. + */ + u64 value64 = 0xffffffff00000000ULL | value; + + asm volatile("msr pmccntr_el0, %0" :: "r" (value64)); + } else if (armv8pmu_select_counter(idx) == idx) asm volatile("msr pmxevcntr_el0, %0" :: "r" (value)); } @@ -768,8 +776,11 @@ static void armv8pmu_reset(void *info) armv8pmu_disable_intens(idx); } - /* Initialize & Reset PMNC: C and P bits. */ - armv8pmu_pmcr_write(ARMV8_PMCR_P | ARMV8_PMCR_C); + /* + * Initialize & Reset PMNC. Request overflow interrupt for + * 64 bit cycle counter but cheat in armv8pmu_write_counter(). + */ + armv8pmu_pmcr_write(ARMV8_PMCR_P | ARMV8_PMCR_C | ARMV8_PMCR_LC); } static int armv8_pmuv3_map_event(struct perf_event *event) |