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Message-ID: <CAPqJEFoTy3B2bc3OPa8WZWphra+2X9-oaQwDkD6UG4gViFy92Q@mail.gmail.com>
Date: Fri, 6 Feb 2026 19:22:00 +0800
From: Eric Lin <eric.lin@...ive.com>
To: Anup Patel <apatel@...tanamicro.com>
Cc: Rob Herring <robh@...nel.org>, Krzysztof Kozlowski <krzk+dt@...nel.org>,
Conor Dooley <conor+dt@...nel.org>, Paul Walmsley <paul.walmsley@...ive.com>,
Palmer Dabbelt <palmer@...belt.com>, Greg KH <gregkh@...uxfoundation.org>,
Alexander Shishkin <alexander.shishkin@...ux.intel.com>, Ian Rogers <irogers@...gle.com>,
Mark Rutland <mark.rutland@....com>, devicetree@...r.kernel.org,
Alexandre Ghiti <alex@...ti.fr>, Atish Patra <atish.patra@...ux.dev>,
Peter Zijlstra <peterz@...radead.org>, Anup Patel <anup@...infault.org>,
Adrian Hunter <adrian.hunter@...el.com>, linux-kernel@...r.kernel.org,
Mayuresh Chitale <mchitale@...tanamicro.com>, Ingo Molnar <mingo@...hat.com>,
Jiri Olsa <jolsa@...nel.org>, Mayuresh Chitale <mchitale@...il.com>,
Namhyung Kim <namhyung@...nel.org>, linux-riscv@...ts.infradead.org,
Andrew Jones <ajones@...tanamicro.com>, Liang Kan <kan.liang@...ux.intel.com>
Subject: Re: [PATCH v2 10/12] perf tools: Add RISC-V trace PMU record capabilities
Hi Anup,
On Sat, Nov 1, 2025 at 11:45 PM Anup Patel <apatel@...tanamicro.com> wrote:
>
> From: Mayuresh Chitale <mchitale@...tanamicro.com>
>
> Introduce the required auxiliary API functions allowing the perf core
> to interact with RISC-V trace perf driver.
>
> Co-developed-by: Anup Patel <apatel@...tanamicro.com>
> Signed-off-by: Anup Patel <apatel@...tanamicro.com>
> Signed-off-by: Mayuresh Chitale <mchitale@...tanamicro.com>
> ---
> tools/perf/arch/riscv/util/Build | 1 +
> tools/perf/arch/riscv/util/auxtrace.c | 218 ++++++++++++++++++++++++++
> tools/perf/util/auxtrace.c | 1 +
> tools/perf/util/auxtrace.h | 1 +
> tools/perf/util/rvtrace.h | 18 +++
> 5 files changed, 239 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 58a672246024..2ba1fb98a0ad 100644
> --- a/tools/perf/arch/riscv/util/Build
> +++ b/tools/perf/arch/riscv/util/Build
> @@ -3,3 +3,4 @@ perf-util-y += header.o
>
> perf-util-$(CONFIG_LIBTRACEEVENT) += kvm-stat.o
> perf-util-$(CONFIG_LIBDW_DWARF_UNWIND) += unwind-libdw.o
> +perf-util-$(CONFIG_AUXTRACE) += 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..adc86bd38998
> --- /dev/null
> +++ b/tools/perf/arch/riscv/util/auxtrace.c
> @@ -0,0 +1,218 @@
> +// 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 <time.h>
> +
> +#include <internal/lib.h> // page_size
> +#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"
> +
> +#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;
> +
> + 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");
> + 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();
> +}
> +
> +static void rvtrace_recording_free(struct auxtrace_record *itr)
> +{
> + struct rvtrace_recording *ptr =
> + container_of(itr, struct rvtrace_recording, itr);
> +
> + 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_etm = NULL;
^^^^^^^^^
Nit: it seems "found_etm" implies ARM CoreSight ETM. Since this is for
RISC-V, should we rename this to "found_rvtrace" or simply "found_pmu"
to avoid confusion? Thanks
Regards,
Eric Lin
> + 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_etm)
> + found_etm = find_pmu_for_event(&rvtrace_pmu, 1, evsel);
> + }
> +
> + if (found_etm)
> + 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 1539c1dc823c..c905563e0d8a 100644
> --- a/tools/perf/util/auxtrace.c
> +++ b/tools/perf/util/auxtrace.c
> @@ -1394,6 +1394,7 @@ int perf_event__process_auxtrace_info(struct perf_session *session,
> 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 e0a5b39fed12..1c89a281a06c 100644
> --- a/tools/perf/util/auxtrace.h
> +++ b/tools/perf/util/auxtrace.h
> @@ -51,6 +51,7 @@ 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..93c041db8660
> --- /dev/null
> +++ b/tools/perf/util/rvtrace.h
> @@ -0,0 +1,18 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + * Copyright(C) 2015 Linaro Limited. All rights reserved.
> + * Author: Mathieu Poirier <mathieu.poirier@...aro.org>
> + */
> +
> +#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
> --
> 2.43.0
>
>
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