[RFC 6/6] RISC-V: Add perf platform driver based on SBI PMU extension
Atish Patra
atish.patra at wdc.com
Fri Mar 19 23:01:06 GMT 2021
RISC-V SBI specification added a PMU extension that allows to configure
/start/stop any pmu counter. The RISC-V perf can use most of the generic
perf features except interrupt overflow and event filtering based on
privilege mode which will be added in future.
It also allows to monitor a handful of firmware counters that can provide
insights into firmware activity during a performance analysis.
Signed-off-by: Atish Patra <atish.patra at wdc.com>
---
drivers/perf/Kconfig | 8 +
drivers/perf/Makefile | 1 +
drivers/perf/riscv_pmu.c | 12 +-
drivers/perf/riscv_pmu_sbi.c | 464 +++++++++++++++++++++++++++++++++
include/linux/perf/riscv_pmu.h | 1 +
5 files changed, 485 insertions(+), 1 deletion(-)
create mode 100644 drivers/perf/riscv_pmu_sbi.c
diff --git a/drivers/perf/Kconfig b/drivers/perf/Kconfig
index 1546a487d970..2acb5feaab35 100644
--- a/drivers/perf/Kconfig
+++ b/drivers/perf/Kconfig
@@ -73,6 +73,14 @@ config RISCV_PMU_LEGACY
implementation on RISC-V based systems. This only allows counting
of cycle/instruction counter and will be removed in future.
+config RISCV_PMU_SBI
+ depends on RISCV_PMU
+ bool "RISC-V PMU based on SBI PMU extension"
+ default y
+ help
+ Say y if you want to use the CPU performance monitor
+ using SBI PMU extension on RISC-V based systems.
+
config ARM_PMU_ACPI
depends on ARM_PMU && ACPI
def_bool y
diff --git a/drivers/perf/Makefile b/drivers/perf/Makefile
index e8aa666a9d28..7bcac4b5a983 100644
--- a/drivers/perf/Makefile
+++ b/drivers/perf/Makefile
@@ -13,6 +13,7 @@ obj-$(CONFIG_QCOM_L3_PMU) += qcom_l3_pmu.o
obj-$(CONFIG_RISCV_PMU) += riscv_pmu.o
ifeq ($(CONFIG_RISCV_PMU), y)
obj-$(CONFIG_RISCV_PMU_LEGACY) += riscv_pmu_legacy.o
+obj-$(CONFIG_RISCV_PMU_SBI) += riscv_pmu_sbi.o
endif
obj-$(CONFIG_THUNDERX2_PMU) += thunderx2_pmu.o
obj-$(CONFIG_XGENE_PMU) += xgene_pmu.o
diff --git a/drivers/perf/riscv_pmu.c b/drivers/perf/riscv_pmu.c
index 838dca2ffca8..95e4ca07dd29 100644
--- a/drivers/perf/riscv_pmu.c
+++ b/drivers/perf/riscv_pmu.c
@@ -16,6 +16,8 @@
#include <linux/printk.h>
#include <linux/smp.h>
+#include <asm/sbi.h>
+
static unsigned long csr_read_num(int csr_num)
{
#define switchcase_csr_read(__csr_num, __val) {\
@@ -350,7 +352,15 @@ static int riscv_pmu_device_probe(struct platform_device *pdev)
if (!pmu)
return -ENOMEM;
- riscv_pmu_legacy_init(pmu);
+ if (sbi_major_version() == 0 &&
+ sbi_minor_version() == 3 &&
+ sbi_probe_extension(SBI_EXT_PMU) > 0) {
+ pr_info("SBI PMU extension detected\n");
+ riscv_pmu_sbi_init(pmu);
+ } else {
+ pr_info("Legacy PMU is in use as SBI PMU extension is not available\n");
+ riscv_pmu_legacy_init(pmu);
+ }
cpuhp_setup_state(CPUHP_AP_PERF_RISCV_STARTING,
"perf/riscv/pmu:starting",
diff --git a/drivers/perf/riscv_pmu_sbi.c b/drivers/perf/riscv_pmu_sbi.c
new file mode 100644
index 000000000000..1f27802bd0e9
--- /dev/null
+++ b/drivers/perf/riscv_pmu_sbi.c
@@ -0,0 +1,464 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * RISC-V performance counter support.
+ *
+ * Copyright (C) 2021 Western Digital Corporation or its affiliates.
+ *
+ * This code is based on ARM perf event code which is in turn based on
+ * sparc64 and x86 code.
+ */
+
+#include <linux/perf/riscv_pmu.h>
+
+#include <asm/sbi.h>
+
+union sbi_pmu_ctr_info {
+ unsigned long value;
+ struct {
+ unsigned long csr:12;
+ unsigned long width:6;
+#if __riscv_xlen == 32
+ unsigned long reserved:13;
+#else
+ unsigned long reserved:45;
+#endif
+ unsigned long type:1;
+ };
+};
+
+/**
+ * RISC-V doesn't have hetergenous harts yet. This need to be part of
+ * per_cpu in case of harts with different pmu counters
+ */
+static union sbi_pmu_ctr_info *pmu_ctr_list;
+
+struct pmu_event_data {
+ union {
+ union {
+ struct hw_gen_event {
+ uint32_t event_code:16;
+ uint32_t event_type:4;
+ uint32_t reserved:12;
+ } hw_gen_event;
+ struct hw_cache_event {
+ uint32_t result_id:1;
+ uint32_t op_id:2;
+ uint32_t cache_id:13;
+ uint32_t event_type:4;
+ uint32_t reserved:12;
+ } hw_cache_event;
+ };
+ uint32_t event_idx;
+ };
+};
+
+static const struct pmu_event_data pmu_hw_event_map[] = {
+ [PERF_COUNT_HW_CPU_CYCLES] = {.hw_gen_event = {
+ SBI_PMU_HW_CPU_CYCLES,
+ SBI_PMU_EVENT_TYPE_HW, 0}},
+ [PERF_COUNT_HW_INSTRUCTIONS] = {.hw_gen_event = {
+ SBI_PMU_HW_INSTRUCTIONS,
+ SBI_PMU_EVENT_TYPE_HW, 0}},
+ [PERF_COUNT_HW_CACHE_REFERENCES] = {.hw_gen_event = {
+ SBI_PMU_HW_CACHE_REFERENCES,
+ SBI_PMU_EVENT_TYPE_HW, 0}},
+ [PERF_COUNT_HW_CACHE_MISSES] = {.hw_gen_event = {
+ SBI_PMU_HW_CACHE_MISSES,
+ SBI_PMU_EVENT_TYPE_HW, 0}},
+ [PERF_COUNT_HW_BRANCH_INSTRUCTIONS] = {.hw_gen_event = {
+ SBI_PMU_HW_BRANCH_INSTRUCTIONS,
+ SBI_PMU_EVENT_TYPE_HW, 0}},
+ [PERF_COUNT_HW_BRANCH_MISSES] = {.hw_gen_event = {
+ SBI_PMU_HW_BRANCH_MISSES,
+ SBI_PMU_EVENT_TYPE_HW, 0}},
+ [PERF_COUNT_HW_BUS_CYCLES] = {.hw_gen_event = {
+ SBI_PMU_HW_BUS_CYCLES,
+ SBI_PMU_EVENT_TYPE_HW, 0}},
+ [PERF_COUNT_HW_STALLED_CYCLES_FRONTEND] = {.hw_gen_event = {
+ SBI_PMU_HW_STALLED_CYCLES_FRONTEND,
+ SBI_PMU_EVENT_TYPE_HW, 0}},
+ [PERF_COUNT_HW_STALLED_CYCLES_BACKEND] = {.hw_gen_event = {
+ SBI_PMU_HW_STALLED_CYCLES_BACKEND,
+ SBI_PMU_EVENT_TYPE_HW, 0}},
+ [PERF_COUNT_HW_REF_CPU_CYCLES] = {.hw_gen_event = {
+ SBI_PMU_HW_REF_CPU_CYCLES,
+ SBI_PMU_EVENT_TYPE_HW, 0}},
+};
+
+#define C(x) PERF_COUNT_HW_CACHE_##x
+static const struct pmu_event_data pmu_cache_event_map[PERF_COUNT_HW_CACHE_MAX]
+[PERF_COUNT_HW_CACHE_OP_MAX]
+[PERF_COUNT_HW_CACHE_RESULT_MAX] = {
+ [C(L1D)] = {
+ [C(OP_READ)] = {
+ [C(RESULT_ACCESS)] = {.hw_cache_event = {C(RESULT_ACCESS),
+ C(OP_READ), C(L1D), SBI_PMU_EVENT_TYPE_CACHE, 0}},
+ [C(RESULT_MISS)] = {.hw_cache_event = {C(RESULT_MISS),
+ C(OP_READ), C(L1D), SBI_PMU_EVENT_TYPE_CACHE, 0}},
+ },
+ [C(OP_WRITE)] = {
+ [C(RESULT_ACCESS)] = {.hw_cache_event = {C(RESULT_ACCESS),
+ C(OP_WRITE), C(L1D), SBI_PMU_EVENT_TYPE_CACHE, 0}},
+ [C(RESULT_MISS)] = {.hw_cache_event = {C(RESULT_MISS),
+ C(OP_WRITE), C(L1D), SBI_PMU_EVENT_TYPE_CACHE, 0}},
+ },
+ [C(OP_PREFETCH)] = {
+ [C(RESULT_ACCESS)] = {.hw_cache_event = {C(RESULT_ACCESS),
+ C(OP_PREFETCH), C(L1D), SBI_PMU_EVENT_TYPE_CACHE, 0}},
+ [C(RESULT_MISS)] = {.hw_cache_event = {C(RESULT_MISS),
+ C(OP_PREFETCH), C(L1D), SBI_PMU_EVENT_TYPE_CACHE, 0}},
+ },
+ },
+ [C(L1I)] = {
+ [C(OP_READ)] = {
+ [C(RESULT_ACCESS)] = {.hw_cache_event = {C(RESULT_ACCESS),
+ C(OP_READ), C(L1I), SBI_PMU_EVENT_TYPE_CACHE, 0}},
+ [C(RESULT_MISS)] = {.hw_cache_event = {C(RESULT_MISS), C(OP_READ),
+ C(L1I), SBI_PMU_EVENT_TYPE_CACHE, 0}},
+ },
+ [C(OP_WRITE)] = {
+ [C(RESULT_ACCESS)] = {.hw_cache_event = {C(RESULT_ACCESS),
+ C(OP_WRITE), C(L1I), SBI_PMU_EVENT_TYPE_CACHE, 0}},
+ [C(RESULT_MISS)] = {.hw_cache_event = {C(RESULT_MISS),
+ C(OP_WRITE), C(L1I), SBI_PMU_EVENT_TYPE_CACHE, 0}},
+ },
+ [C(OP_PREFETCH)] = {
+ [C(RESULT_ACCESS)] = {.hw_cache_event = {C(RESULT_ACCESS),
+ C(OP_PREFETCH), C(L1I), SBI_PMU_EVENT_TYPE_CACHE, 0}},
+ [C(RESULT_MISS)] = {.hw_cache_event = {C(RESULT_MISS),
+ C(OP_PREFETCH), C(L1I), SBI_PMU_EVENT_TYPE_CACHE, 0}},
+ },
+ },
+ [C(LL)] = {
+ [C(OP_READ)] = {
+ [C(RESULT_ACCESS)] = {.hw_cache_event = {C(RESULT_ACCESS),
+ C(OP_READ), C(LL), SBI_PMU_EVENT_TYPE_CACHE, 0}},
+ [C(RESULT_MISS)] = {.hw_cache_event = {C(RESULT_MISS),
+ C(OP_READ), C(LL), SBI_PMU_EVENT_TYPE_CACHE, 0}},
+ },
+ [C(OP_WRITE)] = {
+ [C(RESULT_ACCESS)] = {.hw_cache_event = {C(RESULT_ACCESS),
+ C(OP_WRITE), C(LL), SBI_PMU_EVENT_TYPE_CACHE, 0}},
+ [C(RESULT_MISS)] = {.hw_cache_event = {C(RESULT_MISS),
+ C(OP_WRITE), C(LL), SBI_PMU_EVENT_TYPE_CACHE, 0}},
+ },
+ [C(OP_PREFETCH)] = {
+ [C(RESULT_ACCESS)] = {.hw_cache_event = {C(RESULT_ACCESS),
+ C(OP_PREFETCH), C(LL), SBI_PMU_EVENT_TYPE_CACHE, 0}},
+ [C(RESULT_MISS)] = {.hw_cache_event = {C(RESULT_MISS),
+ C(OP_PREFETCH), C(LL), SBI_PMU_EVENT_TYPE_CACHE, 0}},
+ },
+ },
+ [C(DTLB)] = {
+ [C(OP_READ)] = {
+ [C(RESULT_ACCESS)] = {.hw_cache_event = {C(RESULT_ACCESS),
+ C(OP_READ), C(DTLB), SBI_PMU_EVENT_TYPE_CACHE, 0}},
+ [C(RESULT_MISS)] = {.hw_cache_event = {C(RESULT_MISS),
+ C(OP_READ), C(DTLB), SBI_PMU_EVENT_TYPE_CACHE, 0}},
+ },
+ [C(OP_WRITE)] = {
+ [C(RESULT_ACCESS)] = {.hw_cache_event = {C(RESULT_ACCESS),
+ C(OP_WRITE), C(DTLB), SBI_PMU_EVENT_TYPE_CACHE, 0}},
+ [C(RESULT_MISS)] = {.hw_cache_event = {C(RESULT_MISS),
+ C(OP_WRITE), C(DTLB), SBI_PMU_EVENT_TYPE_CACHE, 0}},
+ },
+ [C(OP_PREFETCH)] = {
+ [C(RESULT_ACCESS)] = {.hw_cache_event = {C(RESULT_ACCESS),
+ C(OP_PREFETCH), C(DTLB), SBI_PMU_EVENT_TYPE_CACHE, 0}},
+ [C(RESULT_MISS)] = {.hw_cache_event = {C(RESULT_MISS),
+ C(OP_PREFETCH), C(DTLB), SBI_PMU_EVENT_TYPE_CACHE, 0}},
+ },
+ },
+ [C(ITLB)] = {
+ [C(OP_READ)] = {
+ [C(RESULT_ACCESS)] = {.hw_cache_event = {C(RESULT_ACCESS),
+ C(OP_READ), C(ITLB), SBI_PMU_EVENT_TYPE_CACHE, 0}},
+ [C(RESULT_MISS)] = {.hw_cache_event = {C(RESULT_MISS),
+ C(OP_READ), C(ITLB), SBI_PMU_EVENT_TYPE_CACHE, 0}},
+ },
+ [C(OP_WRITE)] = {
+ [C(RESULT_ACCESS)] = {.hw_cache_event = {C(RESULT_ACCESS),
+ C(OP_WRITE), C(ITLB), SBI_PMU_EVENT_TYPE_CACHE, 0}},
+ [C(RESULT_MISS)] = {.hw_cache_event = {C(RESULT_MISS),
+ C(OP_WRITE), C(ITLB), SBI_PMU_EVENT_TYPE_CACHE, 0}},
+ },
+ [C(OP_PREFETCH)] = {
+ [C(RESULT_ACCESS)] = {.hw_cache_event = {C(RESULT_ACCESS),
+ C(OP_PREFETCH), C(ITLB), SBI_PMU_EVENT_TYPE_CACHE, 0}},
+ [C(RESULT_MISS)] = {.hw_cache_event = {C(RESULT_MISS),
+ C(OP_PREFETCH), C(ITLB), SBI_PMU_EVENT_TYPE_CACHE, 0}},
+ },
+ },
+ [C(BPU)] = {
+ [C(OP_READ)] = {
+ [C(RESULT_ACCESS)] = {.hw_cache_event = {C(RESULT_ACCESS),
+ C(OP_READ), C(BPU), SBI_PMU_EVENT_TYPE_CACHE, 0}},
+ [C(RESULT_MISS)] = {.hw_cache_event = {C(RESULT_MISS),
+ C(OP_READ), C(BPU), SBI_PMU_EVENT_TYPE_CACHE, 0}},
+ },
+ [C(OP_WRITE)] = {
+ [C(RESULT_ACCESS)] = {.hw_cache_event = {C(RESULT_ACCESS),
+ C(OP_WRITE), C(BPU), SBI_PMU_EVENT_TYPE_CACHE, 0}},
+ [C(RESULT_MISS)] = {.hw_cache_event = {C(RESULT_MISS),
+ C(OP_WRITE), C(BPU), SBI_PMU_EVENT_TYPE_CACHE, 0}},
+ },
+ [C(OP_PREFETCH)] = {
+ [C(RESULT_ACCESS)] = {.hw_cache_event = {C(RESULT_ACCESS),
+ C(OP_PREFETCH), C(BPU), SBI_PMU_EVENT_TYPE_CACHE, 0}},
+ [C(RESULT_MISS)] = {.hw_cache_event = {C(RESULT_MISS),
+ C(OP_PREFETCH), C(BPU), SBI_PMU_EVENT_TYPE_CACHE, 0}},
+ },
+ },
+ [C(NODE)] = {
+ [C(OP_READ)] = {
+ [C(RESULT_ACCESS)] = {.hw_cache_event = {C(RESULT_ACCESS),
+ C(OP_READ), C(NODE), SBI_PMU_EVENT_TYPE_CACHE, 0}},
+ [C(RESULT_MISS)] = {.hw_cache_event = {C(RESULT_MISS),
+ C(OP_READ), C(NODE), SBI_PMU_EVENT_TYPE_CACHE, 0}},
+ },
+ [C(OP_WRITE)] = {
+ [C(RESULT_ACCESS)] = {.hw_cache_event = {C(RESULT_ACCESS),
+ C(OP_WRITE), C(NODE), SBI_PMU_EVENT_TYPE_CACHE, 0}},
+ [C(RESULT_MISS)] = {.hw_cache_event = {C(RESULT_MISS),
+ C(OP_WRITE), C(NODE), SBI_PMU_EVENT_TYPE_CACHE, 0}},
+ },
+ [C(OP_PREFETCH)] = {
+ [C(RESULT_ACCESS)] = {.hw_cache_event = {C(RESULT_ACCESS),
+ C(OP_PREFETCH), C(NODE), SBI_PMU_EVENT_TYPE_CACHE, 0}},
+ [C(RESULT_MISS)] = {.hw_cache_event = {C(RESULT_MISS),
+ C(OP_PREFETCH), C(NODE), SBI_PMU_EVENT_TYPE_CACHE, 0}},
+ },
+ },
+};
+
+static int pmu_sbi_get_ctr_width(int idx)
+{
+ return pmu_ctr_list[idx].width;
+}
+
+static int pmu_sbi_get_ctr_idx(struct perf_event *event)
+{
+ struct hw_perf_event *hwc = &event->hw;
+ struct riscv_pmu *rvpmu = to_riscv_pmu(event->pmu);
+ struct cpu_hw_events *cpuc = this_cpu_ptr(rvpmu->hw_events);
+ struct sbiret ret;
+ int idx;
+ uint64_t cbase = 0;
+ uint64_t cmask = GENMASK_ULL(rvpmu->num_counters, 0);
+
+ /* retrieve the available counter index */
+ ret = sbi_ecall(SBI_EXT_PMU, SBI_EXT_PMU_COUNTER_CFG_MATCH, cbase, cmask,
+ hwc->event_base, hwc->config, 0, 0);
+ if (ret.error) {
+ pr_debug("Not able to find a counter for event %lx config %llx\n",
+ hwc->event_base, hwc->config);
+ return sbi_err_map_linux_errno(ret.error);
+ }
+
+ idx = ret.value;
+ if (idx >= rvpmu->num_counters || !pmu_ctr_list[idx].value)
+ return -ENOENT;
+
+ /* Additional sanity check for the counter id */
+ if (!test_and_set_bit(idx, cpuc->used_event_ctrs))
+ return idx;
+ else
+ return -ENOENT;
+}
+
+static void pmu_sbi_clear_ctr_idx(struct perf_event *event)
+{
+
+ struct hw_perf_event *hwc = &event->hw;
+ struct riscv_pmu *rvpmu = to_riscv_pmu(event->pmu);
+ struct cpu_hw_events *cpuc = this_cpu_ptr(rvpmu->hw_events);
+ int idx = hwc->idx;
+
+ clear_bit(idx, cpuc->used_event_ctrs);
+}
+
+static int pmu_map_cache_event(u64 config)
+{
+ unsigned int cache_type, cache_op, cache_result, ret;
+
+ cache_type = (config >> 0) & 0xff;
+ if (cache_type >= PERF_COUNT_HW_CACHE_MAX)
+ return -EINVAL;
+
+ cache_op = (config >> 8) & 0xff;
+ if (cache_op >= PERF_COUNT_HW_CACHE_OP_MAX)
+ return -EINVAL;
+
+ cache_result = (config >> 16) & 0xff;
+ if (cache_result >= PERF_COUNT_HW_CACHE_RESULT_MAX)
+ return -EINVAL;
+
+ ret = pmu_cache_event_map[cache_type][cache_op][cache_result].event_idx;
+
+ return ret;
+}
+
+static bool pmu_sbi_is_fw_event(struct perf_event *event)
+{
+ u32 type = event->attr.type;
+ u64 config = event->attr.config;
+
+ if ((type == PERF_TYPE_RAW) && ((config >> 63) == 1))
+ return true;
+ else
+ return false;
+}
+
+static int pmu_sbi_map_event(struct perf_event *event, u64 *econfig)
+{
+ u32 type = event->attr.type;
+ u64 config = event->attr.config;
+ int bSoftware;
+ u64 raw_config_val;
+ int ret;
+
+ switch (type) {
+ case PERF_TYPE_HARDWARE:
+ if (config >= PERF_COUNT_HW_MAX)
+ return -EINVAL;
+ ret = pmu_hw_event_map[event->attr.config].event_idx;
+ break;
+ case PERF_TYPE_HW_CACHE:
+ ret = pmu_map_cache_event(config);
+ break;
+ case PERF_TYPE_RAW:
+ bSoftware = config >> 63;
+ raw_config_val = config & RISCV_PMU_RAW_EVENT_MASK;
+ if (bSoftware) {
+ if (raw_config_val < SBI_PMU_FW_MAX)
+ ret = (raw_config_val & 0xFFFF) |
+ (SBI_PMU_EVENT_TYPE_FW << 16);
+ else
+ return -EINVAL;
+ } else {
+ ret = RISCV_PMU_RAW_EVENT_IDX;
+ *econfig = raw_config_val;
+ }
+ break;
+ default:
+ ret = -EINVAL;
+ break;
+ }
+
+ return ret;
+}
+
+static u64 pmu_sbi_read_ctr(struct perf_event *event)
+{
+ struct hw_perf_event *hwc = &event->hw;
+ int idx = hwc->idx;
+ struct sbiret ret;
+ union sbi_pmu_ctr_info info;
+ u64 val = 0;
+
+ if (pmu_sbi_is_fw_event(event)) {
+ ret = sbi_ecall(SBI_EXT_PMU, SBI_EXT_PMU_COUNTER_FW_READ,
+ hwc->idx, 0, 0, 0, 0, 0);
+ if (!ret.error)
+ val = ret.value;
+ } else {
+ info = pmu_ctr_list[idx];
+ val = riscv_pmu_read_ctr_csr(info.csr);
+ if (IS_ENABLED(CONFIG_32BIT))
+ val = ((u64)riscv_pmu_read_ctr_csr(info.csr + 0x80)) << 32 | val;
+ }
+
+ return val;
+}
+
+static void pmu_sbi_start_ctr(struct perf_event *event, u64 ival)
+{
+ struct sbiret ret;
+ struct hw_perf_event *hwc = &event->hw;
+
+ ret = sbi_ecall(SBI_EXT_PMU, SBI_EXT_PMU_COUNTER_START, hwc->idx,
+ ival, 0, 0, 0, 0);
+ if (ret.error)
+ pr_err("Starting counter idx %d failed with error %d\n",
+ hwc->idx, sbi_err_map_linux_errno(ret.error));
+}
+
+static void pmu_sbi_stop_ctr(struct perf_event *event)
+{
+ struct sbiret ret;
+ struct hw_perf_event *hwc = &event->hw;
+ struct riscv_pmu *rvpmu = to_riscv_pmu(event->pmu);
+ struct cpu_hw_events *cpuc = this_cpu_ptr(rvpmu->hw_events);
+ bool breset = false;
+
+ if (cpuc->events[hwc->idx] == NULL)
+ breset = true;
+ ret = sbi_ecall(SBI_EXT_PMU, SBI_EXT_PMU_COUNTER_STOP, hwc->idx, breset, 0, 0, 0, 0);
+ if (ret.error)
+ pr_err("Stopping counter idx %d failed with error %d\n",
+ hwc->idx, sbi_err_map_linux_errno(ret.error));
+}
+
+static int pmu_sbi_find_num_ctrs(void)
+{
+ struct sbiret ret;
+
+ ret = sbi_ecall(SBI_EXT_PMU, SBI_EXT_PMU_NUM_COUNTERS, 0, 0, 0, 0, 0, 0);
+ if (!ret.error)
+ return ret.value;
+ else
+ return sbi_err_map_linux_errno(ret.error);
+}
+
+static int pmu_sbi_get_ctrinfo(int nctr)
+{
+ struct sbiret ret;
+ int i, num_hw_ctr = 0, num_fw_ctr = 0;
+ union sbi_pmu_ctr_info cinfo;
+
+ pmu_ctr_list = kzalloc(sizeof(*pmu_ctr_list) * nctr, GFP_KERNEL);
+ if (!pmu_ctr_list)
+ return -ENOMEM;
+
+ for (i = 0; i <= nctr; i++) {
+ ret = sbi_ecall(SBI_EXT_PMU, SBI_EXT_PMU_COUNTER_GET_INFO, i, 0, 0, 0, 0, 0);
+ if (ret.error)
+ /* The logical counter ids are not expected to be contiguous */
+ continue;
+ cinfo.value = ret.value;
+ if (cinfo.type == SBI_PMU_CTR_TYPE_FW)
+ num_fw_ctr++;
+ else
+ num_hw_ctr++;
+ pmu_ctr_list[i].value = cinfo.value;
+ }
+
+ pr_info("There are %d firmware & %d hardware counters available\n",
+ num_fw_ctr, num_hw_ctr);
+
+ return 0;
+}
+
+void riscv_pmu_sbi_init(struct riscv_pmu *pmu)
+{
+ int num_counters;
+
+ num_counters = pmu_sbi_find_num_ctrs();
+ if (num_counters < 0) {
+ pr_err("SBI PMU extension doesn't provide any counters\n");
+ return;
+ }
+
+ /* cache all the information about counters now */
+ if (pmu_sbi_get_ctrinfo(num_counters))
+ return;
+
+ pmu->num_counters = num_counters;
+ pmu->start_ctr = pmu_sbi_start_ctr;
+ pmu->stop_ctr = pmu_sbi_stop_ctr;
+ pmu->map_event = pmu_sbi_map_event;
+ pmu->get_ctr_idx = pmu_sbi_get_ctr_idx;
+ pmu->get_ctr_width = pmu_sbi_get_ctr_width;
+ pmu->clear_ctr_idx = pmu_sbi_clear_ctr_idx;
+ pmu->read_ctr = pmu_sbi_read_ctr;
+}
diff --git a/include/linux/perf/riscv_pmu.h b/include/linux/perf/riscv_pmu.h
index 3a02b496609d..e54ba2a998c2 100644
--- a/include/linux/perf/riscv_pmu.h
+++ b/include/linux/perf/riscv_pmu.h
@@ -54,6 +54,7 @@ struct riscv_pmu {
#define to_riscv_pmu(p) (container_of(p, struct riscv_pmu, pmu))
unsigned long riscv_pmu_read_ctr_csr(unsigned long csr);
void riscv_pmu_legacy_init(struct riscv_pmu *pmu);
+void riscv_pmu_sbi_init(struct riscv_pmu *pmu);
#endif /* CONFIG_RISCV_PMU */
--
2.25.1
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