Re: [PATCH V8 23/23] perf tools: adding coresight etm PMU record capabilities

[Adrian Hunter]

On 25/01/16 23:10, Arnaldo Carvalho de Melo wrote:
> Em Mon, Jan 25, 2016 at 01:51:18PM -0700, Mathieu Poirier escreveu:
>> On 14 January 2016 at 14:46, Mathieu Poirier <mathieu.poirier@xxxxxxxxxx> wrote:
>>> Coresight ETMs are IP blocks used to perform HW assisted tracing
>>> on a CPU core.  This patch introduce the required auxiliary API
>>> functions allowing the perf core to interact with a tracer.
>>>
>>> Cc: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
>>> Cc: Ingo Molnar <mingo@xxxxxxxxxx>
>>> Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
>>> Signed-off-by: Mathieu Poirier <mathieu.poirier@xxxxxxxxxx>
>>> ---
>>>  MAINTAINERS                         |   3 +
>>>  tools/perf/arch/arm/util/Build      |   2 +-
>>>  tools/perf/arch/arm/util/auxtrace.c |  54 +++++
>>>  tools/perf/arch/arm/util/cs_etm.c   | 466 ++++++++++++++++++++++++++++++++++++
>>>  tools/perf/arch/arm/util/cs_etm.h   |  44 ++++
>>>  tools/perf/util/auxtrace.c          |   1 +
>>>  tools/perf/util/auxtrace.h          |   1 +
>>>  7 files changed, 570 insertions(+), 1 deletion(-)
>>>  create mode 100644 tools/perf/arch/arm/util/auxtrace.c
>>>  create mode 100644 tools/perf/arch/arm/util/cs_etm.c
>>>  create mode 100644 tools/perf/arch/arm/util/cs_etm.h
>>>
>>> diff --git a/MAINTAINERS b/MAINTAINERS
>>> index b2a92245eece..a81b2737ebc3 100644
>>> --- a/MAINTAINERS
>>> +++ b/MAINTAINERS
>>> @@ -1008,6 +1008,9 @@ F:        Documentation/trace/coresight.txt
>>>  F:     Documentation/devicetree/bindings/arm/coresight.txt
>>>  F:     Documentation/ABI/testing/sysfs-bus-coresight-devices-*
>>>  F:     tools/perf/arch/arm/util/pmu.c
>>> +F:     tools/perf/arch/arm/util/auxtrace.c
>>> +F:     tools/perf/arch/arm/util/cs_etm.c
>>> +F:     tools/perf/arch/arm/util/cs_etm.h
>>>
>>>  ARM/CORGI MACHINE SUPPORT
>>>  M:     Richard Purdie <rpurdie@xxxxxxxxx>
>>> diff --git a/tools/perf/arch/arm/util/Build b/tools/perf/arch/arm/util/Build
>>> index 66ab0b05549c..0a25a1248f42 100644
>>> --- a/tools/perf/arch/arm/util/Build
>>> +++ b/tools/perf/arch/arm/util/Build
>>> @@ -3,4 +3,4 @@ libperf-$(CONFIG_DWARF) += dwarf-regs.o
>>>  libperf-$(CONFIG_LIBUNWIND)          += unwind-libunwind.o
>>>  libperf-$(CONFIG_LIBDW_DWARF_UNWIND) += unwind-libdw.o
>>>
>>> -libperf-$(CONFIG_AUXTRACE) += pmu.o
>>> +libperf-$(CONFIG_AUXTRACE) += pmu.o auxtrace.o cs_etm.o
>>> diff --git a/tools/perf/arch/arm/util/auxtrace.c b/tools/perf/arch/arm/util/auxtrace.c
>>> new file mode 100644
>>> index 000000000000..d327316f0e8a
>>> --- /dev/null
>>> +++ b/tools/perf/arch/arm/util/auxtrace.c
>>> @@ -0,0 +1,54 @@
>>> +/*
>>> + * Copyright(C) 2015 Linaro Limited. All rights reserved.
>>> + * Author: Mathieu Poirier <mathieu.poirier@xxxxxxxxxx>
>>> + *
>>> + * This program is free software; you can redistribute it and/or modify it
>>> + * under the terms of the GNU General Public License version 2 as published by
>>> + * the Free Software Foundation.
>>> + *
>>> + * This program is distributed in the hope that it will be useful, but WITHOUT
>>> + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
>>> + * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
>>> + * more details.
>>> + *
>>> + * You should have received a copy of the GNU General Public License along with
>>> + * this program.  If not, see <http://www.gnu.org/licenses/>.
>>> + */
>>> +
>>> +#include <stdbool.h>
>>> +#include <linux/coresight-pmu.h>
>>> +
>>> +#include "../../util/auxtrace.h"
>>> +#include "../../util/evlist.h"
>>> +#include "../../util/pmu.h"
>>> +#include "cs_etm.h"
>>> +
>>> +struct auxtrace_record
>>> +*auxtrace_record__init(struct perf_evlist *evlist, int *err)
>>> +{
>>> +       struct perf_pmu *cs_etm_pmu;
>>> +       struct perf_evsel *evsel;
>>> +       bool found_etm = false;
>>> +
>>> +       cs_etm_pmu = perf_pmu__find(CORESIGHT_ETM_PMU_NAME);
>>> +
>>> +        if (evlist) {
>>> +               evlist__for_each(evlist, evsel) {
>>> +                       if (cs_etm_pmu &&
>>> +                           evsel->attr.type == cs_etm_pmu->type)
>>> +                               found_etm = true;
>>> +               }
>>> +       }
>>> +
>>> +       if (found_etm)
>>> +               return cs_etm_record_init(err);
>>> +
>>> +       /*
>>> +        * Clear 'err' even if we haven't found a cs_etm event - that way perf
>>> +        * record can still be used even if tracers aren't present.  The NULL
>>> +        * return value will take care of telling the infrastructure HW tracing
>>> +        * isn't available.
>>> +        */
>>> +       *err = 0;
>>> +       return NULL;
>>> +}
>>> diff --git a/tools/perf/arch/arm/util/cs_etm.c b/tools/perf/arch/arm/util/cs_etm.c
>>> new file mode 100644
>>> index 000000000000..5710b90e23d5
>>> --- /dev/null
>>> +++ b/tools/perf/arch/arm/util/cs_etm.c
>>> @@ -0,0 +1,466 @@
>>> +/*
>>> + * Copyright(C) 2015 Linaro Limited. All rights reserved.
>>> + * Author: Mathieu Poirier <mathieu.poirier@xxxxxxxxxx>
>>> + *
>>> + * This program is free software; you can redistribute it and/or modify it
>>> + * under the terms of the GNU General Public License version 2 as published by
>>> + * the Free Software Foundation.
>>> + *
>>> + * This program is distributed in the hope that it will be useful, but WITHOUT
>>> + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
>>> + * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
>>> + * more details.
>>> + *
>>> + * You should have received a copy of the GNU General Public License along with
>>> + * this program.  If not, see <http://www.gnu.org/licenses/>.
>>> + */
>>> +
>>> +#include <api/fs/fs.h>
>>> +#include <linux/bitops.h>
>>> +#include <linux/coresight-pmu.h>
>>> +#include <linux/kernel.h>
>>> +#include <linux/log2.h>
>>> +#include <linux/types.h>
>>> +
>>> +#include "../../perf.h"
>>> +#include "../../util/auxtrace.h"
>>> +#include "../../util/cpumap.h"
>>> +#include "../../util/evlist.h"
>>> +#include "../../util/pmu.h"
>>> +#include "../../util/thread_map.h"
>>> +#include "cs_etm.h"
>>> +
>>> +#include <stdlib.h>
>>> +
>>> +#define KiB(x) ((x) * 1024)
>>> +#define MiB(x) ((x) * 1024 * 1024)
>>> +
>>> +struct cs_etm_recording {
>>> +       struct auxtrace_record  itr;
>>> +       struct perf_pmu         *cs_etm_pmu;
>>> +       struct perf_evlist      *evlist;
>>> +       bool                    snapshot_mode;
>>> +       size_t                  snapshot_size;
>>> +};
>>> +
>>> +static int cs_etm_parse_snapshot_options(struct auxtrace_record *itr,
>>> +                                        struct record_opts *opts,
>>> +                                        const char *str)
>>> +{
>>> +       struct cs_etm_recording *ptr =
>>> +                               container_of(itr, struct cs_etm_recording, itr);
>>> +       unsigned long long snapshot_size = 0;
>>> +       char *endptr;
>>> +
>>> +       if (str) {
>>> +               snapshot_size = strtoull(str, &endptr, 0);
>>> +               if (*endptr || snapshot_size > SIZE_MAX)
>>> +                       return -1;
>>> +       }
>>> +
>>> +       opts->auxtrace_snapshot_mode = true;
>>> +       opts->auxtrace_snapshot_size = snapshot_size;
>>> +       ptr->snapshot_size = snapshot_size;
>>> +
>>> +       return 0;
>>> +}
>>> +
>>> +static int cs_etm_recording_options(struct auxtrace_record *itr,
>>> +                                   struct perf_evlist *evlist,
>>> +                                   struct record_opts *opts)
>>> +{
>>> +       struct cs_etm_recording *ptr =
>>> +                               container_of(itr, struct cs_etm_recording, itr);
>>> +       struct perf_pmu *cs_etm_pmu = ptr->cs_etm_pmu;
>>> +       struct perf_evsel *evsel, *cs_etm_evsel = NULL;
>>> +       const struct cpu_map *cpus = evlist->cpus;
>>> +       bool privileged = (geteuid() == 0 || perf_event_paranoid() < 0);
>>> +
>>> +       ptr->evlist = evlist;
>>> +       ptr->snapshot_mode = opts->auxtrace_snapshot_mode;
>>> +
>>> +       evlist__for_each(evlist, evsel) {
>>> +               if (evsel->attr.type == cs_etm_pmu->type) {
>>> +                       if (cs_etm_evsel) {
>>> +                               pr_err("There may be only one %s event\n",
>>> +                                      CORESIGHT_ETM_PMU_NAME);
>>> +                               return -EINVAL;
>>> +                       }
>>> +                       evsel->attr.freq = 0;
>>> +                       evsel->attr.sample_period = 1;
>>> +                       cs_etm_evsel = evsel;
>>> +                       opts->full_auxtrace = true;
>>> +               }
>>> +       }
>>> +
>>> +       /* no need to continue if at least one event of interest was found */
>>> +       if (!cs_etm_evsel)
>>> +               return 0;
>>> +
>>> +       if (opts->use_clockid) {
>>> +               pr_err("Cannot use clockid (-k option) with %s\n",
>>> +                      CORESIGHT_ETM_PMU_NAME);
>>> +               return -EINVAL;
>>> +       }
>>> +
>>> +       /* we are in snapshot mode */
>>> +       if (opts->auxtrace_snapshot_mode) {
>>> +               /*
>>> +                * No size were given to '-S' or '-m,', so go with
>>> +                * the default
>>> +                */
>>> +               if (!opts->auxtrace_snapshot_size &&
>>> +                   !opts->auxtrace_mmap_pages) {
>>> +                       if (privileged) {
>>> +                               opts->auxtrace_mmap_pages = MiB(4) / page_size;
>>> +                       } else {
>>> +                               opts->auxtrace_mmap_pages =
>>> +                                                       KiB(128) / page_size;
>>> +                               if (opts->mmap_pages == UINT_MAX)
>>> +                                       opts->mmap_pages = KiB(256) / page_size;
>>> +                       }
>>> +               } else if (!opts->auxtrace_mmap_pages && !privileged &&
>>> +                                               opts->mmap_pages == UINT_MAX) {
>>> +                       opts->mmap_pages = KiB(256) / page_size;
>>> +               }
>>> +
>>> +               /*
>>> +                * '-m,xyz' was specified but no snapshot size, so make the
>>> +                * snapshot size as big as the auxtrace mmap area.
>>> +                */
>>> +               if (!opts->auxtrace_snapshot_size) {
>>> +                       opts->auxtrace_snapshot_size =
>>> +                               opts->auxtrace_mmap_pages * (size_t)page_size;
>>> +               }
>>> +
>>> +               /*
>>> +                * -Sxyz was specified but no auxtrace mmap area, so make the
>>> +                * auxtrace mmap area big enough to fit the requested snapshot
>>> +                * size.
>>> +                */
>>> +               if (!opts->auxtrace_mmap_pages) {
>>> +                       size_t sz = opts->auxtrace_snapshot_size;
>>> +
>>> +                       sz = round_up(sz, page_size) / page_size;
>>> +                       opts->auxtrace_mmap_pages = roundup_pow_of_two(sz);
>>> +               }
>>> +
>>> +               /* Snapshost size can't be bigger than the auxtrace area */
>>> +               if (opts->auxtrace_snapshot_size >
>>> +                               opts->auxtrace_mmap_pages * (size_t)page_size) {
>>> +                       pr_err("Snapshot size %zu must not be greater than AUX area tracing mmap size %zu\n",
>>> +                              opts->auxtrace_snapshot_size,
>>> +                              opts->auxtrace_mmap_pages * (size_t)page_size);
>>> +                       return -EINVAL;
>>> +               }
>>> +
>>> +               /* Something went wrong somewhere - this shouldn't happen */
>>> +               if (!opts->auxtrace_snapshot_size ||
>>> +                   !opts->auxtrace_mmap_pages) {
>>> +                       pr_err("Failed to calculate default snapshot size and/or AUX area tracing mmap pages\n");
>>> +                       return -EINVAL;
>>> +               }
>>> +       }
>>> +
>>> +       /* We are in full trace mode but '-m,xyz' wasn't specified */
>>> +        if (opts->full_auxtrace && !opts->auxtrace_mmap_pages) {
>>> +               if (privileged) {
>>> +                       opts->auxtrace_mmap_pages = MiB(4) / 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 provided by user */
>>> +       if (opts->auxtrace_mmap_pages) {
>>> +               unsigned int max_page = (KiB(128) / page_size);
>>> +               size_t sz = opts->auxtrace_mmap_pages * (size_t)page_size;
>>> +
>>> +               if (!privileged &&
>>> +                   opts->auxtrace_mmap_pages > max_page) {
>>> +                       opts->auxtrace_mmap_pages = max_page;
>>> +                       pr_err("auxtrace too big, truncating to %d\n",
>>> +                              max_page);
>>> +               }
>>> +
>>> +               if (!is_power_of_2(sz)) {
>>> +                       pr_err("Invalid mmap size for %s: must be a power of 2\n",
>>> +                              CORESIGHT_ETM_PMU_NAME);
>>> +                       return -EINVAL;
>>> +               }
>>> +       }
>>> +
>>> +       if (opts->auxtrace_snapshot_mode)
>>> +               pr_debug2("%s snapshot size: %zu\n", CORESIGHT_ETM_PMU_NAME,
>>> +                         opts->auxtrace_snapshot_size);
>>> +
>>> +       if (cs_etm_evsel) {
>>> +               /*
>>> +                * To obtain the auxtrace buffer file descriptor, the auxtrace
>>> +                * event must come first.
>>> +                */
>>> +               perf_evlist__to_front(evlist, cs_etm_evsel);
>>> +               /*
>>> +                * In the case of per-cpu mmaps, we need the CPU on the
>>> +                * AUX event.
>>> +                */
>>> +               if (!cpu_map__empty(cpus))
>>> +                       perf_evsel__set_sample_bit(cs_etm_evsel, CPU);
>>> +       }
>>> +
>>> +       /* Add dummy event to keep tracking */
>>> +       if (opts->full_auxtrace) {
>>> +               struct perf_evsel *tracking_evsel;
>>> +               int err;
>>> +
>>> +               err = parse_events(evlist, "dummy:u", NULL);
>>> +               if (err)
>>> +                       return err;
>>> +
>>> +               tracking_evsel = perf_evlist__last(evlist);
>>> +               perf_evlist__set_tracking_event(evlist, tracking_evsel);
>>> +
>>> +               tracking_evsel->attr.freq = 0;
>>> +               tracking_evsel->attr.sample_period = 1;
>>> +
>>> +               /* In per-cpu case, always need the time of mmap events etc */
>>> +               if (!cpu_map__empty(cpus))
>>> +                       perf_evsel__set_sample_bit(tracking_evsel, TIME);
>>> +       }
>>> +
>>> +       return 0;
>>> +}
>>> +
>>> +static u64 cs_etm_get_config(struct auxtrace_record *itr)
>>> +{
>>> +       u64 config = 0;
>>> +       struct cs_etm_recording *ptr =
>>> +                       container_of(itr, struct cs_etm_recording, itr);
>>> +       struct perf_pmu *cs_etm_pmu = ptr->cs_etm_pmu;
>>> +       struct perf_evlist *evlist = ptr->evlist;
>>> +       struct perf_evsel *evsel;
>>> +
>>> +       evlist__for_each(evlist, evsel) {
>>> +               if (evsel->attr.type == cs_etm_pmu->type) {
>>> +                       /*
>>> +                        * Variable perf_event_attr::config is assigned to
>>> +                        * ETMv3/PTM.  The bit fields have been made to match
>>> +                        * the ETMv3.5 ETRMCR register specification.  See the
>>> +                        * PMU_FORMAT_ATTR() declarations in
>>> +                        * drivers/hwtracing/coresight/coresight-perf.c for
>>> +                        * details.
>>> +                        */
>>> +                       config = evsel->attr.config;
>>> +                       break;
>>> +               }
>>> +       }
>>> +
>>> +       return config;
>>> +}
>>> +
>>> +static size_t
>>> +cs_etm_info_priv_size(struct auxtrace_record *itr __maybe_unused,
>>> +                     struct perf_evlist *evlist __maybe_unused)
>>> +{
>>> +       int records;
>>> +       const struct cpu_map *cpus = evlist->cpus;
>>> +
>>> +       if (!cpu_map__empty(cpus)) {
>>> +               records = cpu_map__nr(cpus);
>>> +               goto out;
>>> +       }
>>> +
>>> +       set_max_cpu_num();
>>> +       records = cpu__max_cpu();
>>> +out:
>>> +       return records * CS_ETM_PRIV_SIZE;
>>> +}
>>> +
>>> +static const char *metadata_etmv3_ro[CS_ETM_PRIV_MAX] = {
>>> +       [CS_ETM_ETMCCER]        = "mgmt/etmccer",
>>> +       [CS_ETM_ETMIDR]         = "mgmt/etmidr",
>>> +};
>>> +
>>> +static int cs_etm_get_metadata(int cpu, int index,
>>> +                              struct auxtrace_record *itr,
>>> +                              struct auxtrace_info_event *info)
>>> +{
>>> +       char path[PATH_MAX];
>>> +       int offset = 0, ret = 0;
>>> +       int i, scan;
>>> +       unsigned int val;
>>> +       struct cs_etm_recording *ptr =
>>> +                       container_of(itr, struct cs_etm_recording, itr);
>>> +       struct perf_pmu *cs_etm_pmu = ptr->cs_etm_pmu;
>>> +
>>> +       offset = index * CS_ETM_PRIV_MAX;
>>> +
>>> +       /* Build generic header portion */
>>> +       info->priv[offset + CS_ETM_MAGIC] = __perf_cs_etm_magic;
>>> +       info->priv[offset + CS_ETM_CPU] = cpu;
>>> +       info->priv[offset + CS_ETM_SNAPSHOT] = ptr->snapshot_mode;
>>> +
>>> +       /* Get user configurables from the session */
>>> +       info->priv[offset + CS_ETM_ETMCR] = cs_etm_get_config(itr);
>>> +       info->priv[offset + CS_ETM_ETMTRACEIDR] = coresight_get_trace_id(cpu);
>>> +
>>> +       /* Get RO metadata from sysfs */
>>> +       for (i = CS_ETM_ETMCCER; i < CS_ETM_PRIV_MAX; i++) {
>>> +               snprintf(path, PATH_MAX, "cpu%d/%s", cpu, metadata_etmv3_ro[i]);
>>> +
>>> +               scan = perf_pmu__scan_file(cs_etm_pmu, path, "%x", &val);
>>> +               if (scan != 1) {
>>> +                       ret = -EINVAL;
>>> +                       break;
>>> +               }
>>> +
>>> +               info->priv[offset + i] = val;
>>> +       }
>>> +
>>> +       return ret;
>>> +}
>>> +
>>> +static int cs_etm_info_fill(struct auxtrace_record *itr,
>>> +                           struct perf_session *session,
>>> +                           struct auxtrace_info_event *auxtrace_info,
>>> +                           size_t priv_size)
>>> +{
>>> +       int i, nr_cpu, ret = 0;
>>> +       const struct cpu_map *cpus = session->evlist->cpus;
>>> +
>>> +       if (priv_size != cs_etm_info_priv_size(itr, session->evlist))
>>> +               return -EINVAL;
>>> +
>>> +       if (!session->evlist->nr_mmaps)
>>> +               return -EINVAL;
>>> +
>>> +       auxtrace_info->type = PERF_AUXTRACE_CS_ETM;
>>> +
>>> +       /* cpu map is not empty, we have specific CPUs to work with */
>>> +       if (!cpu_map__empty(cpus)) {
>>> +               for (i = 0; i < cpu_map__nr(cpus); i++) {
>>> +                       ret = cs_etm_get_metadata(cpus->map[i], i,
>>> +                                                 itr, auxtrace_info);
>>> +                       if (ret)
>>> +                               goto out;
>>> +               }
>>> +       } else {
>>> +               /* get configuration for all CPUs in the system */
>>> +               nr_cpu = cpu__max_cpu();
>>> +               for (i = 0; i < nr_cpu; i++) {
>>> +                       ret = cs_etm_get_metadata(i, i, itr, auxtrace_info);
>>> +                       if (ret)
>>> +                               goto out;
>>> +               }
>>> +       }
>>> +
>>> +out:
>>> +       return ret;
>>> +}
>>> +
>>> +static int cs_etm_find_snapshot(struct auxtrace_record *itr __maybe_unused,
>>> +                               int idx, struct auxtrace_mmap *mm,
>>> +                               unsigned char *data __maybe_unused,
>>> +                               u64 *head, u64 *old)
>>> +{
>>> +       pr_debug3("%s: mmap index %d old head %zu new head %zu size %zu\n",
>>> +                 __func__, idx, (size_t)*old, (size_t)*head, mm->len);
>>> +
>>> +       *old = *head;
>>> +       *head += mm->len;
>>> +
>>> +       return 0;
>>> +}
>>> +
>>> +static int cs_etm_snapshot_start(struct auxtrace_record *itr)
>>> +{
>>> +       struct cs_etm_recording *ptr =
>>> +                       container_of(itr, struct cs_etm_recording, itr);
>>> +       struct perf_evsel *evsel;
>>> +
>>> +       evlist__for_each(ptr->evlist, evsel) {
>>> +               if (evsel->attr.type == ptr->cs_etm_pmu->type)
>>> +                       return perf_evlist__disable_event(ptr->evlist, evsel);
>>> +       }
>>> +       return -EINVAL;
>>> +}
>>> +
>>> +static int cs_etm_snapshot_finish(struct auxtrace_record *itr)
>>> +{
>>> +       struct cs_etm_recording *ptr =
>>> +                       container_of(itr, struct cs_etm_recording, itr);
>>> +       struct perf_evsel *evsel;
>>> +
>>> +       evlist__for_each(ptr->evlist, evsel) {
>>> +               if (evsel->attr.type == ptr->cs_etm_pmu->type)
>>> +                       return perf_evlist__enable_event(ptr->evlist, evsel);
>>> +       }
>>> +       return -EINVAL;
>>> +}
>>> +
>>> +static u64 cs_etm_reference(struct auxtrace_record *itr __maybe_unused)
>>> +{
>>> +       return (((u64) rand() <<  0) & 0x00000000FFFFFFFFull) |
>>> +               (((u64) rand() << 32) & 0xFFFFFFFF00000000ull);
>>> +}
>>> +
>>> +static void cs_etm_recording_free(struct auxtrace_record *itr)
>>> +{
>>> +       struct cs_etm_recording *ptr =
>>> +                       container_of(itr, struct cs_etm_recording, itr);
>>> +       free(ptr);
>>> +}
>>> +
>>> +static int cs_etm_read_finish(struct auxtrace_record *itr, int idx)
>>> +{
>>> +       struct cs_etm_recording *ptr =
>>> +                       container_of(itr, struct cs_etm_recording, itr);
>>> +       struct perf_evsel *evsel;
>>> +
>>> +       evlist__for_each(ptr->evlist, evsel) {
>>> +               if (evsel->attr.type == ptr->cs_etm_pmu->type)
>>> +                       return perf_evlist__enable_event_idx(ptr->evlist,
>>> +                                                            evsel, idx);
>>> +       }
>>> +
>>> +       return -EINVAL;
>>> +}
>>> +
>>> +struct auxtrace_record *cs_etm_record_init(int *err)
>>> +{
>>> +       struct perf_pmu *cs_etm_pmu;
>>> +       struct cs_etm_recording *ptr;
>>> +
>>> +       cs_etm_pmu = perf_pmu__find(CORESIGHT_ETM_PMU_NAME);
>>> +
>>> +       if (!cs_etm_pmu) {
>>> +               *err = -EINVAL;
>>> +               goto out;
>>> +       }
>>> +
>>> +       ptr = zalloc(sizeof(struct cs_etm_recording));
>>> +       if (!ptr) {
>>> +               *err = -ENOMEM;
>>> +               goto out;
>>> +       }
>>> +
>>> +       ptr->cs_etm_pmu                 = cs_etm_pmu;
>>> +       ptr->itr.parse_snapshot_options = cs_etm_parse_snapshot_options;
>>> +       ptr->itr.recording_options      = cs_etm_recording_options;
>>> +       ptr->itr.info_priv_size         = cs_etm_info_priv_size;
>>> +       ptr->itr.info_fill              = cs_etm_info_fill;
>>> +       ptr->itr.find_snapshot          = cs_etm_find_snapshot;
>>> +       ptr->itr.snapshot_start         = cs_etm_snapshot_start;
>>> +       ptr->itr.snapshot_finish        = cs_etm_snapshot_finish;
>>> +       ptr->itr.reference              = cs_etm_reference;
>>> +       ptr->itr.free                   = cs_etm_recording_free;
>>> +       ptr->itr.read_finish            = cs_etm_read_finish;
>>> +
>>> +       *err = 0;
>>> +       return &ptr->itr;
>>> +out:
>>> +       return NULL;
>>> +}
>>> diff --git a/tools/perf/arch/arm/util/cs_etm.h b/tools/perf/arch/arm/util/cs_etm.h
>>> new file mode 100644
>>> index 000000000000..7e85c1b43598
>>> --- /dev/null
>>> +++ b/tools/perf/arch/arm/util/cs_etm.h
>>> @@ -0,0 +1,44 @@
>>> +/*
>>> + * Copyright(C) 2015 Linaro Limited. All rights reserved.
>>> + * Author: Mathieu Poirier <mathieu.poirier@xxxxxxxxxx>
>>> + *
>>> + * This program is free software; you can redistribute it and/or modify it
>>> + * under the terms of the GNU General Public License version 2 as published by
>>> + * the Free Software Foundation.
>>> + *
>>> + * This program is distributed in the hope that it will be useful, but WITHOUT
>>> + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
>>> + * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
>>> + * more details.
>>> + *
>>> + * You should have received a copy of the GNU General Public License along with
>>> + * this program.  If not, see <http://www.gnu.org/licenses/>.
>>> + */
>>> +
>>> +#ifndef INCLUDE__PERF_CS_ETM_H__
>>> +#define INCLUDE__PERF_CS_ETM_H__
>>> +
>>> +/* Beginning of header common to both ETMv3 and V4 */
>>> +enum {
>>> +       CS_ETM_MAGIC,
>>> +       CS_ETM_CPU,
>>> +       CS_ETM_SNAPSHOT,
>>> +};
>>> +
>>> +/* ETMv3/PTM metadata */
>>> +enum {
>>> +       /* Dynamic, configurable parameters */
>>> +       CS_ETM_ETMCR = CS_ETM_SNAPSHOT + 1,
>>> +       CS_ETM_ETMTRACEIDR,
>>> +       /* RO, taken from sysFS */
>>> +       CS_ETM_ETMCCER,
>>> +       CS_ETM_ETMIDR,
>>> +       CS_ETM_PRIV_MAX,
>>> +};
>>> +
>>> +static const u64 __perf_cs_etm_magic   = 0x3030303030303030ULL;
>>> +#define CS_ETM_PRIV_SIZE (CS_ETM_PRIV_MAX * sizeof(u64))
>>> +
>>> +struct auxtrace_record *cs_etm_record_init(int *err);
>>> +
>>> +#endif
>>> diff --git a/tools/perf/util/auxtrace.c b/tools/perf/util/auxtrace.c
>>> index cc1c9ce5cc56..a6f291dbc4d9 100644
>>> --- a/tools/perf/util/auxtrace.c
>>> +++ b/tools/perf/util/auxtrace.c
>>> @@ -892,6 +892,7 @@ int perf_event__process_auxtrace_info(struct perf_tool *tool __maybe_unused,
>>>                 return intel_pt_process_auxtrace_info(event, session);
>>>         case PERF_AUXTRACE_INTEL_BTS:
>>>                 return intel_bts_process_auxtrace_info(event, session);
>>> +       case PERF_AUXTRACE_CS_ETM:
>>>         case PERF_AUXTRACE_UNKNOWN:
>>>         default:
>>>                 return -EINVAL;
>>> diff --git a/tools/perf/util/auxtrace.h b/tools/perf/util/auxtrace.h
>>> index e5a8e2d4f2af..adb53e7bcabf 100644
>>> --- a/tools/perf/util/auxtrace.h
>>> +++ b/tools/perf/util/auxtrace.h
>>> @@ -41,6 +41,7 @@ enum auxtrace_type {
>>>         PERF_AUXTRACE_UNKNOWN,
>>>         PERF_AUXTRACE_INTEL_PT,
>>>         PERF_AUXTRACE_INTEL_BTS,
>>> +       PERF_AUXTRACE_CS_ETM,
>>>  };
>>>
>>>  enum itrace_period_type {
>>> --
>>> 2.1.4
>>>
>>
>> Arnaldo,
>>
>> Last but not least, this is the final patch that I would like you to
>> review before queing.
>>
>> It has been rebased to 4.5-rc1 here [1] for your convenience.  I will
>> be happy to use another baseline should that be more adequate for you.
> 
> Adrian,
> 
> 	One more, are you ok with this?

Looks OK, apart from adding linux/coresight-pmu.h to the manifest, but I
mentioned that on another patch.

However there is no decoder, which begs the question, is there anything you
can actually do with the perf.data file?  Might be a bit confusing for users
if they can capture traces but not use perf tools on the resulting perf.data
file?

Nevertheless, for what is there now:

Acked-by: Adrian Hunter <adrian.hunter@xxxxxxxxx>