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Subject[v6 6/9] RISC-V: Add perf platform driver based on SBI PMU extension
Date
From: Atish Patra <atish.patra@wdc.com>

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@wdc.com>
Signed-off-by: Atish Patra <atishp@rivosinc.com>
---
drivers/perf/Kconfig | 10 +
drivers/perf/Makefile | 1 +
drivers/perf/riscv_pmu.c | 2 +
drivers/perf/riscv_pmu_sbi.c | 578 +++++++++++++++++++++++++++++++++
include/linux/cpuhotplug.h | 1 +
include/linux/perf/riscv_pmu.h | 6 +-
6 files changed, 596 insertions(+), 2 deletions(-)
create mode 100644 drivers/perf/riscv_pmu_sbi.c

diff --git a/drivers/perf/Kconfig b/drivers/perf/Kconfig
index 386162ad858a..5645b5615c14 100644
--- a/drivers/perf/Kconfig
+++ b/drivers/perf/Kconfig
@@ -76,6 +76,16 @@ config RISCV_PMU_LEGACY
of cycle/instruction counter and doesn't support counter overflow,
or programmable counters. It will be removed in future.

+config RISCV_PMU_SBI
+ depends on RISCV_PMU && RISCV_SBI
+ 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. This option provides
+ full perf feature support i.e. counter overflow, privilege mode
+ filtering, counter configuration.
+
config ARM_PMU_ACPI
depends on ARM_PMU && ACPI
def_bool y
diff --git a/drivers/perf/Makefile b/drivers/perf/Makefile
index c3d3268d495b..f149735166e1 100644
--- a/drivers/perf/Makefile
+++ b/drivers/perf/Makefile
@@ -12,6 +12,7 @@ obj-$(CONFIG_QCOM_L2_PMU) += qcom_l2_pmu.o
obj-$(CONFIG_QCOM_L3_PMU) += qcom_l3_pmu.o
obj-$(CONFIG_RISCV_PMU) += riscv_pmu.o
obj-$(CONFIG_RISCV_PMU_LEGACY) += riscv_pmu_legacy.o
+obj-$(CONFIG_RISCV_PMU_SBI) += riscv_pmu_sbi.o
obj-$(CONFIG_THUNDERX2_PMU) += thunderx2_pmu.o
obj-$(CONFIG_XGENE_PMU) += xgene_pmu.o
obj-$(CONFIG_ARM_SPE_PMU) += arm_spe_pmu.o
diff --git a/drivers/perf/riscv_pmu.c b/drivers/perf/riscv_pmu.c
index 590a5789c128..b2b8d2074ed0 100644
--- a/drivers/perf/riscv_pmu.c
+++ b/drivers/perf/riscv_pmu.c
@@ -15,6 +15,8 @@
#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) {\
diff --git a/drivers/perf/riscv_pmu_sbi.c b/drivers/perf/riscv_pmu_sbi.c
new file mode 100644
index 000000000000..815d5c509c64
--- /dev/null
+++ b/drivers/perf/riscv_pmu_sbi.c
@@ -0,0 +1,578 @@
+// 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.
+ */
+
+#define pr_fmt(fmt) "riscv-pmu-sbi: " fmt
+
+#include <linux/mod_devicetable.h>
+#include <linux/perf/riscv_pmu.h>
+#include <linux/platform_device.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 sbi_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 sbi_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 sbi_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_ctr_get_width(int idx)
+{
+ return pmu_ctr_list[idx].width;
+}
+
+static bool pmu_sbi_ctr_is_fw(int cidx)
+{
+ union sbi_pmu_ctr_info *info;
+
+ info = &pmu_ctr_list[cidx];
+ if (!info)
+ return false;
+
+ return (info->type == SBI_PMU_CTR_TYPE_FW) ? true : false;
+}
+
+static int pmu_sbi_ctr_get_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 - 1, 0);
+ unsigned long cflags = 0;
+
+ if (event->attr.exclude_kernel)
+ cflags |= SBI_PMU_CFG_FLAG_SET_SINH;
+ if (event->attr.exclude_user)
+ cflags |= SBI_PMU_CFG_FLAG_SET_UINH;
+
+ /* retrieve the available counter index */
+ ret = sbi_ecall(SBI_EXT_PMU, SBI_EXT_PMU_COUNTER_CFG_MATCH, cbase, cmask,
+ cflags, hwc->event_base, hwc->config, 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 (pmu_sbi_ctr_is_fw(idx)) {
+ if (!test_and_set_bit(idx, cpuc->used_fw_ctrs))
+ return idx;
+ } else {
+ if (!test_and_set_bit(idx, cpuc->used_hw_ctrs))
+ return idx;
+ }
+
+ return -ENOENT;
+}
+
+static void pmu_sbi_ctr_clear_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;
+
+ if (pmu_sbi_ctr_is_fw(idx))
+ clear_bit(idx, cpuc->used_fw_ctrs);
+ else
+ clear_bit(idx, cpuc->used_hw_ctrs);
+}
+
+static int pmu_event_find_cache(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_event_map(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_event_find_cache(config);
+ break;
+ case PERF_TYPE_RAW:
+ /*
+ * As per SBI specification, the upper 16 bits must be unused for
+ * a raw event. Use the MSB (63b) to distinguish between hardware
+ * raw event and firmware events.
+ */
+ 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_ctr_read(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_ctr_read_csr(info.csr);
+ if (IS_ENABLED(CONFIG_32BIT))
+ val = ((u64)riscv_pmu_ctr_read_csr(info.csr + 0x80)) << 31 | val;
+ }
+
+ return val;
+}
+
+static void pmu_sbi_ctr_start(struct perf_event *event, u64 ival)
+{
+ struct sbiret ret;
+ struct hw_perf_event *hwc = &event->hw;
+ unsigned long flag = SBI_PMU_START_FLAG_SET_INIT_VALUE;
+
+ ret = sbi_ecall(SBI_EXT_PMU, SBI_EXT_PMU_COUNTER_START, hwc->idx,
+ 1, flag, ival, ival >> 32, 0);
+ if (ret.error && (ret.error != SBI_ERR_ALREADY_STARTED))
+ pr_err("Starting counter idx %d failed with error %d\n",
+ hwc->idx, sbi_err_map_linux_errno(ret.error));
+}
+
+static void pmu_sbi_ctr_stop(struct perf_event *event, unsigned long flag)
+{
+ struct sbiret ret;
+ struct hw_perf_event *hwc = &event->hw;
+
+ ret = sbi_ecall(SBI_EXT_PMU, SBI_EXT_PMU_COUNTER_STOP, hwc->idx, 1, flag, 0, 0, 0);
+ if (ret.error && (ret.error != SBI_ERR_ALREADY_STOPPED) &&
+ flag != SBI_PMU_STOP_FLAG_RESET)
+ 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 = kcalloc(nctr, sizeof(*pmu_ctr_list), 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("%d firmware and %d hardware counters\n", num_fw_ctr, num_hw_ctr);
+
+ return 0;
+}
+
+static int pmu_sbi_starting_cpu(unsigned int cpu, struct hlist_node *node)
+{
+ struct riscv_pmu *pmu = hlist_entry_safe(node, struct riscv_pmu, node);
+
+ /* Enable the access for TIME csr only from the user mode now */
+ csr_write(CSR_SCOUNTEREN, 0x2);
+
+ /* Stop all the counters so that they can be enabled from perf */
+ sbi_ecall(SBI_EXT_PMU, SBI_EXT_PMU_COUNTER_STOP,
+ 0, GENMASK_ULL(pmu->num_counters - 1, 0), 0, 0, 0, 0);
+
+ return 0;
+}
+
+static int pmu_sbi_dying_cpu(unsigned int cpu, struct hlist_node *node)
+{
+ /* Disable all counters access for user mode now */
+ csr_write(CSR_SCOUNTEREN, 0x0);
+
+ return 0;
+}
+
+static int pmu_sbi_device_probe(struct platform_device *pdev)
+{
+ struct riscv_pmu *pmu = NULL;
+ int num_counters;
+ int ret;
+
+ pr_info("SBI PMU extension is available\n");
+ pmu = riscv_pmu_alloc();
+ if (!pmu)
+ return -ENOMEM;
+
+ num_counters = pmu_sbi_find_num_ctrs();
+ if (num_counters < 0) {
+ pr_err("SBI PMU extension doesn't provide any counters\n");
+ return -ENODEV;
+ }
+
+ /* cache all the information about counters now */
+ if (pmu_sbi_get_ctrinfo(num_counters))
+ return -ENODEV;
+
+ pmu->num_counters = num_counters;
+ pmu->ctr_start = pmu_sbi_ctr_start;
+ pmu->ctr_stop = pmu_sbi_ctr_stop;
+ pmu->event_map = pmu_sbi_event_map;
+ pmu->ctr_get_idx = pmu_sbi_ctr_get_idx;
+ pmu->ctr_get_width = pmu_sbi_ctr_get_width;
+ pmu->ctr_clear_idx = pmu_sbi_ctr_clear_idx;
+ pmu->ctr_read = pmu_sbi_ctr_read;
+
+ ret = cpuhp_state_add_instance(CPUHP_AP_PERF_RISCV_STARTING, &pmu->node);
+ if (ret)
+ return ret;
+
+ ret = perf_pmu_register(&pmu->pmu, "cpu", PERF_TYPE_RAW);
+ if (ret) {
+ cpuhp_state_remove_instance(CPUHP_AP_PERF_RISCV_STARTING, &pmu->node);
+ return ret;
+ }
+
+ return 0;
+}
+
+static struct platform_driver pmu_sbi_driver = {
+ .probe = pmu_sbi_device_probe,
+ .driver = {
+ .name = RISCV_PMU_PDEV_NAME,
+ },
+};
+
+static int __init pmu_sbi_devinit(void)
+{
+ int ret;
+ struct platform_device *pdev;
+
+ if (sbi_spec_version < sbi_mk_version(0, 3) ||
+ sbi_probe_extension(SBI_EXT_PMU) <= 0) {
+ return 0;
+ }
+
+ ret = cpuhp_setup_state_multi(CPUHP_AP_PERF_RISCV_STARTING,
+ "perf/riscv/pmu:starting",
+ pmu_sbi_starting_cpu, pmu_sbi_dying_cpu);
+ if (ret) {
+ pr_err("CPU hotplug notifier could not be registered: %d\n",
+ ret);
+ return ret;
+ }
+
+ ret = platform_driver_register(&pmu_sbi_driver);
+ if (ret)
+ return ret;
+
+ pdev = platform_device_register_simple(RISCV_PMU_PDEV_NAME, -1, NULL, 0);
+ if (IS_ERR(pdev)) {
+ platform_driver_unregister(&pmu_sbi_driver);
+ return PTR_ERR(pdev);
+ }
+
+ /* Notify legacy implementation that SBI pmu is available*/
+ riscv_pmu_legacy_skip_init();
+
+ return ret;
+}
+device_initcall(pmu_sbi_devinit)
diff --git a/include/linux/cpuhotplug.h b/include/linux/cpuhotplug.h
index 411a428ace4d..51c7e4929df7 100644
--- a/include/linux/cpuhotplug.h
+++ b/include/linux/cpuhotplug.h
@@ -165,6 +165,7 @@ enum cpuhp_state {
CPUHP_AP_PERF_ARM_HW_BREAKPOINT_STARTING,
CPUHP_AP_PERF_ARM_ACPI_STARTING,
CPUHP_AP_PERF_ARM_STARTING,
+ CPUHP_AP_PERF_RISCV_STARTING,
CPUHP_AP_ARM_L2X0_STARTING,
CPUHP_AP_EXYNOS4_MCT_TIMER_STARTING,
CPUHP_AP_ARM_ARCH_TIMER_STARTING,
diff --git a/include/linux/perf/riscv_pmu.h b/include/linux/perf/riscv_pmu.h
index 9140c491fc54..0f226948c0ca 100644
--- a/include/linux/perf/riscv_pmu.h
+++ b/include/linux/perf/riscv_pmu.h
@@ -31,8 +31,10 @@ struct cpu_hw_events {
int n_events;
/* currently enabled events */
struct perf_event *events[RISCV_MAX_COUNTERS];
- /* currently enabled counters */
- DECLARE_BITMAP(used_event_ctrs, RISCV_MAX_COUNTERS);
+ /* currently enabled hardware counters */
+ DECLARE_BITMAP(used_hw_ctrs, RISCV_MAX_COUNTERS);
+ /* currently enabled firmware counters */
+ DECLARE_BITMAP(used_fw_ctrs, RISCV_MAX_COUNTERS);
};

struct riscv_pmu {
--
2.30.2
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