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authorAlexandre Ghiti <alexghiti@rivosinc.com>2023-08-02 10:03:24 +0200
committerPalmer Dabbelt <palmer@rivosinc.com>2023-08-16 16:28:19 +0200
commit50be342829053d6d4a3c66eacc0e778f6611a37a (patch)
treea375e43caeabc24c1da2fdc59ad9af315c801859 /drivers/perf/riscv_pmu_legacy.c
parentriscv: Prepare for user-space perf event mmap support (diff)
downloadlinux-50be342829053d6d4a3c66eacc0e778f6611a37a.tar.xz
linux-50be342829053d6d4a3c66eacc0e778f6611a37a.zip
drivers: perf: Implement perf event mmap support in the legacy backend
Implement the needed callbacks in the legacy driver so that we can directly access the counters through perf in userspace. Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com> Reviewed-by: Andrew Jones <ajones@ventanamicro.com> Reviewed-by: Atish Patra <atishp@rivosinc.com>
Diffstat (limited to 'drivers/perf/riscv_pmu_legacy.c')
-rw-r--r--drivers/perf/riscv_pmu_legacy.c26
1 files changed, 26 insertions, 0 deletions
diff --git a/drivers/perf/riscv_pmu_legacy.c b/drivers/perf/riscv_pmu_legacy.c
index 6a000abc28bb..79fdd667922e 100644
--- a/drivers/perf/riscv_pmu_legacy.c
+++ b/drivers/perf/riscv_pmu_legacy.c
@@ -71,6 +71,29 @@ static void pmu_legacy_ctr_start(struct perf_event *event, u64 ival)
local64_set(&hwc->prev_count, initial_val);
}
+static uint8_t pmu_legacy_csr_index(struct perf_event *event)
+{
+ return event->hw.idx;
+}
+
+static void pmu_legacy_event_mapped(struct perf_event *event, struct mm_struct *mm)
+{
+ if (event->attr.config != PERF_COUNT_HW_CPU_CYCLES &&
+ event->attr.config != PERF_COUNT_HW_INSTRUCTIONS)
+ return;
+
+ event->hw.flags |= PERF_EVENT_FLAG_USER_READ_CNT;
+}
+
+static void pmu_legacy_event_unmapped(struct perf_event *event, struct mm_struct *mm)
+{
+ if (event->attr.config != PERF_COUNT_HW_CPU_CYCLES &&
+ event->attr.config != PERF_COUNT_HW_INSTRUCTIONS)
+ return;
+
+ event->hw.flags &= ~PERF_EVENT_FLAG_USER_READ_CNT;
+}
+
/*
* This is just a simple implementation to allow legacy implementations
* compatible with new RISC-V PMU driver framework.
@@ -91,6 +114,9 @@ static void pmu_legacy_init(struct riscv_pmu *pmu)
pmu->ctr_get_width = NULL;
pmu->ctr_clear_idx = NULL;
pmu->ctr_read = pmu_legacy_read_ctr;
+ pmu->event_mapped = pmu_legacy_event_mapped;
+ pmu->event_unmapped = pmu_legacy_event_unmapped;
+ pmu->csr_index = pmu_legacy_csr_index;
perf_pmu_register(&pmu->pmu, "cpu", PERF_TYPE_RAW);
}