[PATCH v4 10/12] perf tools: Add RISC-V trace PMU record capabilities
Mayuresh Chitale
mayuresh.chitale at oss.qualcomm.com
Tue Jun 2 04:31:31 PDT 2026
Hi Adrian,
On Wed, May 20, 2026 at 5:00 PM Adrian Hunter <adrian.hunter at intel.com> wrote:
>
> 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>
Thanks, I will address the comments below in the next version.
>
> > ---
> > 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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