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

[Arnaldo Carvalho de Melo]

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?

- Arnaldo