[PATCH v4 10/12] perf tools: Add RISC-V trace PMU record capabilities
Adrian Hunter
adrian.hunter at intel.com
Wed May 20 04:30:10 PDT 2026
On 29/04/2026 15:51, Anup Patel wrote:
> From: Mayuresh Chitale <mayuresh.chitale at oss.qualcomm.com>
>
> Introduce the required auxiliary API functions allowing the perf core
> to interact with RISC-V trace perf driver.
>
> Co-developed-by: Anup Patel <anup.patel at oss.qualcomm.com>
> Signed-off-by: Anup Patel <anup.patel at oss.qualcomm.com>
> Signed-off-by: Mayuresh Chitale <mayuresh.chitale at oss.qualcomm.com>
> Reviewed-by: Nutty Liu <nutty.liu at hotmail.com>
A few minor comments, otherwise:
Reviewed-by: Adrian Hunter <adrian.hunter at intel.com>
> ---
> tools/perf/arch/riscv/util/Build | 1 +
> tools/perf/arch/riscv/util/auxtrace.c | 219 ++++++++++++++++++++++++++
> tools/perf/util/auxtrace.c | 1 +
> tools/perf/util/auxtrace.h | 1 +
> tools/perf/util/rvtrace.h | 18 +++
> 5 files changed, 240 insertions(+)
> create mode 100644 tools/perf/arch/riscv/util/auxtrace.c
> create mode 100644 tools/perf/util/rvtrace.h
>
> diff --git a/tools/perf/arch/riscv/util/Build b/tools/perf/arch/riscv/util/Build
> index 2328fb9a30a3..e07d5525ece6 100644
> --- a/tools/perf/arch/riscv/util/Build
> +++ b/tools/perf/arch/riscv/util/Build
> @@ -1 +1,2 @@
> perf-util-y += header.o
> +perf-util-y += auxtrace.o
> diff --git a/tools/perf/arch/riscv/util/auxtrace.c b/tools/perf/arch/riscv/util/auxtrace.c
> new file mode 100644
> index 000000000000..5293ece2147d
> --- /dev/null
> +++ b/tools/perf/arch/riscv/util/auxtrace.c
> @@ -0,0 +1,219 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Risc-V E-Trace support
> + */
> +
> +#include <linux/kernel.h>
> +#include <linux/types.h>
> +#include <linux/bitops.h>
> +#include <linux/log2.h>
> +#include <linux/zalloc.h>
> +#include <errno.h>
> +#include <time.h>
> +
> +#include <internal/lib.h>
> +#include "../../../util/auxtrace.h"
> +#include "../../../util/cpumap.h"
> +#include "../../../util/debug.h"
> +#include "../../../util/event.h"
> +#include "../../../util/evlist.h"
> +#include "../../../util/evsel.h"
> +#include "../../../util/rvtrace.h"
> +#include "../../../util/pmu.h"
> +#include "../../../util/record.h"
> +#include "../../../util/session.h"
> +#include "../../../util/tsc.h"
tsc.h not needed if rdtsc() is dropped
> +
> +#define RVTRACE_PMU_NAME "rvtrace"
> +#define KiB(x) ((x) * 1024)
> +#define MiB(x) ((x) * 1024 * 1024)
> +
> +struct rvtrace_recording {
> + struct auxtrace_record itr;
> + struct perf_pmu *rvtrace_pmu;
> + struct evlist *evlist;
> +};
> +
> +static size_t rvtrace_info_priv_size(struct auxtrace_record *itr __maybe_unused,
> + struct evlist *evlist __maybe_unused)
> +{
> + return RVTRACE_AUXTRACE_PRIV_SIZE;
> +}
> +
> +static int rvtrace_info_fill(struct auxtrace_record *itr, struct perf_session *session,
> + struct perf_record_auxtrace_info *auxtrace_info, size_t priv_size)
> +{
> + struct rvtrace_recording *ptr = container_of(itr, struct rvtrace_recording, itr);
> + struct perf_pmu *rvtrace_pmu = ptr->rvtrace_pmu;
> +
> + if (priv_size != RVTRACE_AUXTRACE_PRIV_SIZE)
> + return -EINVAL;
> +
> + if (!session->evlist->core.nr_mmaps)
> + return -EINVAL;
This check is not needed
> +
> + auxtrace_info->type = PERF_AUXTRACE_RISCV_TRACE;
> + auxtrace_info->priv[0] = rvtrace_pmu->type;
> +
> + return 0;
> +}
> +
> +static int rvtrace_set_auxtrace_mmap_page(struct record_opts *opts)
> +{
> + bool privileged = perf_event_paranoid_check(-1);
> +
> + if (!opts->full_auxtrace)
> + return 0;
> +
> + if (opts->full_auxtrace && !opts->auxtrace_mmap_pages) {
> + if (privileged) {
> + opts->auxtrace_mmap_pages = MiB(16) / page_size;
> + } else {
> + opts->auxtrace_mmap_pages = KiB(128) / page_size;
> + if (opts->mmap_pages == UINT_MAX)
> + opts->mmap_pages = KiB(256) / page_size;
> + }
> + }
> +
> + /* Validate auxtrace_mmap_pages */
> + if (opts->auxtrace_mmap_pages) {
> + size_t sz = opts->auxtrace_mmap_pages * (size_t)page_size;
> + size_t min_sz = KiB(8);
> +
> + if (sz < min_sz || !is_power_of_2(sz)) {
> + pr_err("Invalid mmap size : must be at least %zuKiB and a power of 2\n",
> + min_sz / 1024);
> + return -EINVAL;
> + }
> + }
> +
> + return 0;
> +}
> +
> +static int rvtrace_recording_options(struct auxtrace_record *itr, struct evlist *evlist,
> + struct record_opts *opts)
> +{
> + struct rvtrace_recording *ptr = container_of(itr, struct rvtrace_recording, itr);
> + struct perf_pmu *rvtrace_pmu = ptr->rvtrace_pmu;
> + struct evsel *evsel, *rvtrace_evsel = NULL;
> + struct evsel *tracking_evsel;
> + int err;
> +
> + ptr->evlist = evlist;
> + evlist__for_each_entry(evlist, evsel) {
> + if (evsel->core.attr.type == rvtrace_pmu->type) {
> + if (rvtrace_evsel) {
> + pr_err("There may be only one " RVTRACE_PMU_NAME "x event\n");
Should "x event\n" be just " event\n"
> + return -EINVAL;
> + }
> + evsel->core.attr.freq = 0;
> + evsel->core.attr.sample_period = 1;
> + evsel->needs_auxtrace_mmap = true;
> + rvtrace_evsel = evsel;
> + opts->full_auxtrace = true;
> + }
> + }
> +
> + err = rvtrace_set_auxtrace_mmap_page(opts);
> + if (err)
> + return err;
> + /*
> + * To obtain the auxtrace buffer file descriptor, the auxtrace event
> + * must come first.
> + */
> + evlist__to_front(evlist, rvtrace_evsel);
> + evsel__set_sample_bit(rvtrace_evsel, TIME);
> +
> + /* Add dummy event to keep tracking */
> + err = parse_event(evlist, "dummy:u");
> + if (err)
> + return err;
> +
> + tracking_evsel = evlist__last(evlist);
> + evlist__set_tracking_event(evlist, tracking_evsel);
> +
> + tracking_evsel->core.attr.freq = 0;
> + tracking_evsel->core.attr.sample_period = 1;
> + evsel__set_sample_bit(tracking_evsel, TIME);
> +
> + return 0;
> +}
> +
> +static u64 rvtrace_reference(struct auxtrace_record *itr __maybe_unused)
> +{
> + return rdtsc();
rdtsc() is 0 (weak fn) for riscv, and does not make sense,
so just return 0.
> +}
> +
> +static void rvtrace_recording_free(struct auxtrace_record *itr)
> +{
> + struct rvtrace_recording *ptr =
> + container_of(itr, struct rvtrace_recording, itr);
Does not need line wrap
> +
> + free(ptr);
> +}
> +
> +static struct auxtrace_record *rvtrace_recording_init(int *err, struct perf_pmu *rvtrace_pmu)
> +{
> + struct rvtrace_recording *ptr;
> +
> + if (!rvtrace_pmu) {
> + *err = -ENODEV;
> + return NULL;
> + }
> +
> + ptr = zalloc(sizeof(*ptr));
> + if (!ptr) {
> + *err = -ENOMEM;
> + return NULL;
> + }
> +
> + ptr->rvtrace_pmu = rvtrace_pmu;
> + ptr->itr.recording_options = rvtrace_recording_options;
> + ptr->itr.info_priv_size = rvtrace_info_priv_size;
> + ptr->itr.info_fill = rvtrace_info_fill;
> + ptr->itr.free = rvtrace_recording_free;
> + ptr->itr.reference = rvtrace_reference;
> + ptr->itr.read_finish = auxtrace_record__read_finish;
> + ptr->itr.alignment = 0;
> +
> + *err = 0;
> + return &ptr->itr;
> +}
> +
> +static struct perf_pmu *find_pmu_for_event(struct perf_pmu **pmus,
> + int pmu_nr, struct evsel *evsel)
> +{
> + int i;
> +
> + if (!pmus)
> + return NULL;
> +
> + for (i = 0; i < pmu_nr; i++) {
> + if (evsel->core.attr.type == pmus[i]->type)
> + return pmus[i];
> + }
> +
> + return NULL;
> +}
> +
> +struct auxtrace_record *auxtrace_record__init(struct evlist *evlist, int *err)
> +{
> + struct perf_pmu *rvtrace_pmu = NULL;
> + struct perf_pmu *found_pmu = NULL;
> + struct evsel *evsel;
> +
> + if (!evlist)
> + return NULL;
> +
> + rvtrace_pmu = perf_pmus__find(RVTRACE_PMU_NAME);
> + evlist__for_each_entry(evlist, evsel) {
> + if (rvtrace_pmu && !found_pmu)
> + found_pmu = find_pmu_for_event(&rvtrace_pmu, 1, evsel);
> + }
> +
> + if (found_pmu)
> + return rvtrace_recording_init(err, rvtrace_pmu);
> +
> + *err = 0;
> + return NULL;
> +}
> diff --git a/tools/perf/util/auxtrace.c b/tools/perf/util/auxtrace.c
> index a224687ffbc1..944a43d48739 100644
> --- a/tools/perf/util/auxtrace.c
> +++ b/tools/perf/util/auxtrace.c
> @@ -1411,6 +1411,7 @@ int perf_event__process_auxtrace_info(const struct perf_tool *tool __maybe_unuse
> case PERF_AUXTRACE_VPA_DTL:
> err = powerpc_vpadtl_process_auxtrace_info(event, session);
> break;
> + case PERF_AUXTRACE_RISCV_TRACE:
> case PERF_AUXTRACE_UNKNOWN:
> default:
> return -EINVAL;
> diff --git a/tools/perf/util/auxtrace.h b/tools/perf/util/auxtrace.h
> index 6947f3f284c0..4f4714c1b53f 100644
> --- a/tools/perf/util/auxtrace.h
> +++ b/tools/perf/util/auxtrace.h
> @@ -46,6 +46,7 @@ enum auxtrace_type {
> PERF_AUXTRACE_S390_CPUMSF,
> PERF_AUXTRACE_HISI_PTT,
> PERF_AUXTRACE_VPA_DTL,
> + PERF_AUXTRACE_RISCV_TRACE,
> };
>
> enum itrace_period_type {
> diff --git a/tools/perf/util/rvtrace.h b/tools/perf/util/rvtrace.h
> new file mode 100644
> index 000000000000..24b32947fb4c
> --- /dev/null
> +++ b/tools/perf/util/rvtrace.h
> @@ -0,0 +1,18 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + * Copyright (c) 2026 Qualcomm Technologies, Inc.
> + * Author: Mayuresh Chitale <mayuresh.chitale at oss.qualcomm.com>
> + */
> +
> +#ifndef INCLUDE__UTIL_PERF_RVTRACE_H__
> +#define INCLUDE__UTIL_PERF_RVTRACE_H__
> +
> +#include "debug.h"
> +#include "auxtrace.h"
> +#include "util/event.h"
> +#include "util/session.h"
> +#include <linux/bits.h>
> +
> +#define RVTRACE_AUXTRACE_PRIV_SIZE sizeof(u64)
> +
> +#endif
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