cs-etm.c

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// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright(C) 2015-2018 Linaro Limited.
 *
 * Author: Tor Jeremiassen <tor@ti.com>
 * Author: Mathieu Poirier <mathieu.poirier@linaro.org>
 */

#include <linux/bitops.h>
#include <linux/err.h>
#include <linux/kernel.h>
#include <linux/log2.h>
#include <linux/types.h>

#include <stdlib.h>

#include "auxtrace.h"
#include "color.h"
#include "cs-etm.h"
#include "cs-etm-decoder/cs-etm-decoder.h"
#include "debug.h"
#include "evlist.h"
#include "intlist.h"
#include "machine.h"
#include "map.h"
#include "perf.h"
#include "thread.h"
#include "thread_map.h"
#include "thread-stack.h"
#include "util.h"

#define MAX_TIMESTAMP (~0ULL)

/*
 * A64 instructions are always 4 bytes
 *
 * Only A64 is supported, so can use this constant for converting between
 * addresses and instruction counts, calculting offsets etc
 */
#define A64_INSTR_SIZE 4

struct cs_etm_auxtrace {
    struct auxtrace auxtrace;
    struct auxtrace_queues queues;
    struct auxtrace_heap heap;
    struct itrace_synth_opts synth_opts;
    struct perf_session *session;
    struct machine *machine;
    struct thread *unknown_thread;

    u8 timeless_decoding;
    u8 snapshot_mode;
    u8 data_queued;
    u8 sample_branches;
    u8 sample_instructions;

    int num_cpu;
    u32 auxtrace_type;
    u64 branches_sample_type;
    u64 branches_id;
    u64 instructions_sample_type;
    u64 instructions_sample_period;
    u64 instructions_id;
    u64 **metadata;
    u64 kernel_start;
    unsigned int pmu_type;
};

struct cs_etm_queue {
    struct cs_etm_auxtrace *etm;
    struct thread *thread;
    struct cs_etm_decoder *decoder;
    struct auxtrace_buffer *buffer;
    const struct cs_etm_state *state;
    union perf_event *event_buf;
    unsigned int queue_nr;
    pid_t pid, tid;
    int cpu;
    u64 time;
    u64 timestamp;
    u64 offset;
    u64 period_instructions;
    struct branch_stack *last_branch;
    struct branch_stack *last_branch_rb;
    size_t last_branch_pos;
    struct cs_etm_packet *prev_packet;
    struct cs_etm_packet *packet;
};

static int cs_etm__update_queues(struct cs_etm_auxtrace *etm);
static int cs_etm__process_timeless_queues(struct cs_etm_auxtrace *etm,
                       pid_t tid, u64 time_);

static void cs_etm__packet_dump(const char *pkt_string)
{
    const char *color = PERF_COLOR_BLUE;
    int len = strlen(pkt_string);

    if (len && (pkt_string[len-1] == '\n'))
        color_fprintf(stdout, color, "  %s", pkt_string);
    else
        color_fprintf(stdout, color, "  %s\n", pkt_string);

    fflush(stdout);
}

static void cs_etm__dump_event(struct cs_etm_auxtrace *etm,
                   struct auxtrace_buffer *buffer)
{
    int i, ret;
    const char *color = PERF_COLOR_BLUE;
    struct cs_etm_decoder_params d_params;
    struct cs_etm_trace_params *t_params;
    struct cs_etm_decoder *decoder;
    size_t buffer_used = 0;

    fprintf(stdout, "\n");
    color_fprintf(stdout, color,
             ". ... CoreSight ETM Trace data: size %zu bytes\n",
             buffer->size);

    /* Use metadata to fill in trace parameters for trace decoder */
    t_params = zalloc(sizeof(*t_params) * etm->num_cpu);
    for (i = 0; i < etm->num_cpu; i++) {
        t_params[i].protocol = CS_ETM_PROTO_ETMV4i;
        t_params[i].etmv4.reg_idr0 = etm->metadata[i][CS_ETMV4_TRCIDR0];
        t_params[i].etmv4.reg_idr1 = etm->metadata[i][CS_ETMV4_TRCIDR1];
        t_params[i].etmv4.reg_idr2 = etm->metadata[i][CS_ETMV4_TRCIDR2];
        t_params[i].etmv4.reg_idr8 = etm->metadata[i][CS_ETMV4_TRCIDR8];
        t_params[i].etmv4.reg_configr =
                    etm->metadata[i][CS_ETMV4_TRCCONFIGR];
        t_params[i].etmv4.reg_traceidr =
                    etm->metadata[i][CS_ETMV4_TRCTRACEIDR];
    }

    /* Set decoder parameters to simply print the trace packets */
    d_params.packet_printer = cs_etm__packet_dump;
    d_params.operation = CS_ETM_OPERATION_PRINT;
    d_params.formatted = true;
    d_params.fsyncs = false;
    d_params.hsyncs = false;
    d_params.frame_aligned = true;

    decoder = cs_etm_decoder__new(etm->num_cpu, &d_params, t_params);

    zfree(&t_params);

    if (!decoder)
        return;
    do {
        size_t consumed;

        ret = cs_etm_decoder__process_data_block(
                decoder, buffer->offset,
                &((u8 *)buffer->data)[buffer_used],
                buffer->size - buffer_used, &consumed);
        if (ret)
            break;

        buffer_used += consumed;
    } while (buffer_used < buffer->size);

    cs_etm_decoder__free(decoder);
}

static int cs_etm__flush_events(struct perf_session *session,
                struct perf_tool *tool)
{
    int ret;
    struct cs_etm_auxtrace *etm = container_of(session->auxtrace,
                           struct cs_etm_auxtrace,
                           auxtrace);
    if (dump_trace)
        return 0;

    if (!tool->ordered_events)
        return -EINVAL;

    if (!etm->timeless_decoding)
        return -EINVAL;

    ret = cs_etm__update_queues(etm);

    if (ret < 0)
        return ret;

    return cs_etm__process_timeless_queues(etm, -1, MAX_TIMESTAMP - 1);
}

static void cs_etm__free_queue(void *priv)
{
    struct cs_etm_queue *etmq = priv;

    if (!etmq)
        return;

    thread__zput(etmq->thread);
    cs_etm_decoder__free(etmq->decoder);
    zfree(&etmq->event_buf);
    zfree(&etmq->last_branch);
    zfree(&etmq->last_branch_rb);
    zfree(&etmq->prev_packet);
    zfree(&etmq->packet);
    free(etmq);
}

static void cs_etm__free_events(struct perf_session *session)
{
    unsigned int i;
    struct cs_etm_auxtrace *aux = container_of(session->auxtrace,
                           struct cs_etm_auxtrace,
                           auxtrace);
    struct auxtrace_queues *queues = &aux->queues;

    for (i = 0; i < queues->nr_queues; i++) {
        cs_etm__free_queue(queues->queue_array[i].priv);
        queues->queue_array[i].priv = NULL;
    }

    auxtrace_queues__free(queues);
}

static void cs_etm__free(struct perf_session *session)
{
    int i;
    struct int_node *inode, *tmp;
    struct cs_etm_auxtrace *aux = container_of(session->auxtrace,
                           struct cs_etm_auxtrace,
                           auxtrace);
    cs_etm__free_events(session);
    session->auxtrace = NULL;

    /* First remove all traceID/CPU# nodes for the RB tree */
    intlist__for_each_entry_safe(inode, tmp, traceid_list)
        intlist__remove(traceid_list, inode);
    /* Then the RB tree itself */
    intlist__delete(traceid_list);

    for (i = 0; i < aux->num_cpu; i++)
        zfree(&aux->metadata[i]);

    thread__zput(aux->unknown_thread);
    zfree(&aux->metadata);
    zfree(&aux);
}

static u32 cs_etm__mem_access(struct cs_etm_queue *etmq, u64 address,
                  size_t size, u8 *buffer)
{
    u8  cpumode;
    u64 offset;
    int len;
    struct   thread *thread;
    struct   machine *machine;
    struct   addr_location al;

    if (!etmq)
        return -1;

    machine = etmq->etm->machine;
    if (address >= etmq->etm->kernel_start)
        cpumode = PERF_RECORD_MISC_KERNEL;
    else
        cpumode = PERF_RECORD_MISC_USER;

    thread = etmq->thread;
    if (!thread) {
        if (cpumode != PERF_RECORD_MISC_KERNEL)
            return -EINVAL;
        thread = etmq->etm->unknown_thread;
    }

    if (!thread__find_map(thread, cpumode, address, &al) || !al.map->dso)
        return 0;

    if (al.map->dso->data.status == DSO_DATA_STATUS_ERROR &&
        dso__data_status_seen(al.map->dso, DSO_DATA_STATUS_SEEN_ITRACE))
        return 0;

    offset = al.map->map_ip(al.map, address);

    map__load(al.map);

    len = dso__data_read_offset(al.map->dso, machine, offset, buffer, size);

    if (len <= 0)
        return 0;

    return len;
}

static struct cs_etm_queue *cs_etm__alloc_queue(struct cs_etm_auxtrace *etm,
                        unsigned int queue_nr)
{
    int i;
    struct cs_etm_decoder_params d_params;
    struct cs_etm_trace_params  *t_params;
    struct cs_etm_queue *etmq;
    size_t szp = sizeof(struct cs_etm_packet);

    etmq = zalloc(sizeof(*etmq));
    if (!etmq)
        return NULL;

    etmq->packet = zalloc(szp);
    if (!etmq->packet)
        goto out_free;

    if (etm->synth_opts.last_branch || etm->sample_branches) {
        etmq->prev_packet = zalloc(szp);
        if (!etmq->prev_packet)
            goto out_free;
    }

    if (etm->synth_opts.last_branch) {
        size_t sz = sizeof(struct branch_stack);

        sz += etm->synth_opts.last_branch_sz *
              sizeof(struct branch_entry);
        etmq->last_branch = zalloc(sz);
        if (!etmq->last_branch)
            goto out_free;
        etmq->last_branch_rb = zalloc(sz);
        if (!etmq->last_branch_rb)
            goto out_free;
    }

    etmq->event_buf = malloc(PERF_SAMPLE_MAX_SIZE);
    if (!etmq->event_buf)
        goto out_free;

    etmq->etm = etm;
    etmq->queue_nr = queue_nr;
    etmq->pid = -1;
    etmq->tid = -1;
    etmq->cpu = -1;

    /* Use metadata to fill in trace parameters for trace decoder */
    t_params = zalloc(sizeof(*t_params) * etm->num_cpu);

    if (!t_params)
        goto out_free;

    for (i = 0; i < etm->num_cpu; i++) {
        t_params[i].protocol = CS_ETM_PROTO_ETMV4i;
        t_params[i].etmv4.reg_idr0 = etm->metadata[i][CS_ETMV4_TRCIDR0];
        t_params[i].etmv4.reg_idr1 = etm->metadata[i][CS_ETMV4_TRCIDR1];
        t_params[i].etmv4.reg_idr2 = etm->metadata[i][CS_ETMV4_TRCIDR2];
        t_params[i].etmv4.reg_idr8 = etm->metadata[i][CS_ETMV4_TRCIDR8];
        t_params[i].etmv4.reg_configr =
                    etm->metadata[i][CS_ETMV4_TRCCONFIGR];
        t_params[i].etmv4.reg_traceidr =
                    etm->metadata[i][CS_ETMV4_TRCTRACEIDR];
    }

    /* Set decoder parameters to simply print the trace packets */
    d_params.packet_printer = cs_etm__packet_dump;
    d_params.operation = CS_ETM_OPERATION_DECODE;
    d_params.formatted = true;
    d_params.fsyncs = false;
    d_params.hsyncs = false;
    d_params.frame_aligned = true;
    d_params.data = etmq;

    etmq->decoder = cs_etm_decoder__new(etm->num_cpu, &d_params, t_params);

    zfree(&t_params);

    if (!etmq->decoder)
        goto out_free;

    /*
     * Register a function to handle all memory accesses required by
     * the trace decoder library.
     */
    if (cs_etm_decoder__add_mem_access_cb(etmq->decoder,
                          0x0L, ((u64) -1L),
                          cs_etm__mem_access))
        goto out_free_decoder;

    etmq->offset = 0;
    etmq->period_instructions = 0;

    return etmq;

out_free_decoder:
    cs_etm_decoder__free(etmq->decoder);
out_free:
    zfree(&etmq->event_buf);
    zfree(&etmq->last_branch);
    zfree(&etmq->last_branch_rb);
    zfree(&etmq->prev_packet);
    zfree(&etmq->packet);
    free(etmq);

    return NULL;
}

static int cs_etm__setup_queue(struct cs_etm_auxtrace *etm,
                   struct auxtrace_queue *queue,
                   unsigned int queue_nr)
{
    struct cs_etm_queue *etmq = queue->priv;

    if (list_empty(&queue->head) || etmq)
        return 0;

    etmq = cs_etm__alloc_queue(etm, queue_nr);

    if (!etmq)
        return -ENOMEM;

    queue->priv = etmq;

    if (queue->cpu != -1)
        etmq->cpu = queue->cpu;

    etmq->tid = queue->tid;

    return 0;
}

static int cs_etm__setup_queues(struct cs_etm_auxtrace *etm)
{
    unsigned int i;
    int ret;

    for (i = 0; i < etm->queues.nr_queues; i++) {
        ret = cs_etm__setup_queue(etm, &etm->queues.queue_array[i], i);
        if (ret)
            return ret;
    }

    return 0;
}

static int cs_etm__update_queues(struct cs_etm_auxtrace *etm)
{
    if (etm->queues.new_data) {
        etm->queues.new_data = false;
        return cs_etm__setup_queues(etm);
    }

    return 0;
}

static inline void cs_etm__copy_last_branch_rb(struct cs_etm_queue *etmq)
{
    struct branch_stack *bs_src = etmq->last_branch_rb;
    struct branch_stack *bs_dst = etmq->last_branch;
    size_t nr = 0;

    /*
     * Set the number of records before early exit: ->nr is used to
     * determine how many branches to copy from ->entries.
     */
    bs_dst->nr = bs_src->nr;

    /*
     * Early exit when there is nothing to copy.
     */
    if (!bs_src->nr)
        return;

    /*
     * As bs_src->entries is a circular buffer, we need to copy from it in
     * two steps.  First, copy the branches from the most recently inserted
     * branch ->last_branch_pos until the end of bs_src->entries buffer.
     */
    nr = etmq->etm->synth_opts.last_branch_sz - etmq->last_branch_pos;
    memcpy(&bs_dst->entries[0],
           &bs_src->entries[etmq->last_branch_pos],
           sizeof(struct branch_entry) * nr);

    /*
     * If we wrapped around at least once, the branches from the beginning
     * of the bs_src->entries buffer and until the ->last_branch_pos element
     * are older valid branches: copy them over.  The total number of
     * branches copied over will be equal to the number of branches asked by
     * the user in last_branch_sz.
     */
    if (bs_src->nr >= etmq->etm->synth_opts.last_branch_sz) {
        memcpy(&bs_dst->entries[nr],
               &bs_src->entries[0],
               sizeof(struct branch_entry) * etmq->last_branch_pos);
    }
}

static inline void cs_etm__reset_last_branch_rb(struct cs_etm_queue *etmq)
{
    etmq->last_branch_pos = 0;
    etmq->last_branch_rb->nr = 0;
}

static inline u64 cs_etm__last_executed_instr(struct cs_etm_packet *packet)
{
    /*
     * The packet records the execution range with an exclusive end address
     *
     * A64 instructions are constant size, so the last executed
     * instruction is A64_INSTR_SIZE before the end address
     * Will need to do instruction level decode for T32 instructions as
     * they can be variable size (not yet supported).
     */
    return packet->end_addr - A64_INSTR_SIZE;
}

static inline u64 cs_etm__instr_count(const struct cs_etm_packet *packet)
{
    /*
     * Only A64 instructions are currently supported, so can get
     * instruction count by dividing.
     * Will need to do instruction level decode for T32 instructions as
     * they can be variable size (not yet supported).
     */
    return (packet->end_addr - packet->start_addr) / A64_INSTR_SIZE;
}

static inline u64 cs_etm__instr_addr(const struct cs_etm_packet *packet,
                     u64 offset)
{
    /*
     * Only A64 instructions are currently supported, so can get
     * instruction address by muliplying.
     * Will need to do instruction level decode for T32 instructions as
     * they can be variable size (not yet supported).
     */
    return packet->start_addr + offset * A64_INSTR_SIZE;
}

static void cs_etm__update_last_branch_rb(struct cs_etm_queue *etmq)
{
    struct branch_stack *bs = etmq->last_branch_rb;
    struct branch_entry *be;

    /*
     * The branches are recorded in a circular buffer in reverse
     * chronological order: we start recording from the last element of the
     * buffer down.  After writing the first element of the stack, move the
     * insert position back to the end of the buffer.
     */
    if (!etmq->last_branch_pos)
        etmq->last_branch_pos = etmq->etm->synth_opts.last_branch_sz;

    etmq->last_branch_pos -= 1;

    be       = &bs->entries[etmq->last_branch_pos];
    be->from = cs_etm__last_executed_instr(etmq->prev_packet);
    be->to   = etmq->packet->start_addr;
    /* No support for mispredict */
    be->flags.mispred = 0;
    be->flags.predicted = 1;

    /*
     * Increment bs->nr until reaching the number of last branches asked by
     * the user on the command line.
     */
    if (bs->nr < etmq->etm->synth_opts.last_branch_sz)
        bs->nr += 1;
}

static int cs_etm__inject_event(union perf_event *event,
                   struct perf_sample *sample, u64 type)
{
    event->header.size = perf_event__sample_event_size(sample, type, 0);
    return perf_event__synthesize_sample(event, type, 0, sample);
}


static int
cs_etm__get_trace(struct cs_etm_buffer *buff, struct cs_etm_queue *etmq)
{
    struct auxtrace_buffer *aux_buffer = etmq->buffer;
    struct auxtrace_buffer *old_buffer = aux_buffer;
    struct auxtrace_queue *queue;

    queue = &etmq->etm->queues.queue_array[etmq->queue_nr];

    aux_buffer = auxtrace_buffer__next(queue, aux_buffer);

    /* If no more data, drop the previous auxtrace_buffer and return */
    if (!aux_buffer) {
        if (old_buffer)
            auxtrace_buffer__drop_data(old_buffer);
        buff->len = 0;
        return 0;
    }

    etmq->buffer = aux_buffer;

    /* If the aux_buffer doesn't have data associated, try to load it */
    if (!aux_buffer->data) {
        /* get the file desc associated with the perf data file */
        int fd = perf_data__fd(etmq->etm->session->data);

        aux_buffer->data = auxtrace_buffer__get_data(aux_buffer, fd);
        if (!aux_buffer->data)
            return -ENOMEM;
    }

    /* If valid, drop the previous buffer */
    if (old_buffer)
        auxtrace_buffer__drop_data(old_buffer);

    buff->offset = aux_buffer->offset;
    buff->len = aux_buffer->size;
    buff->buf = aux_buffer->data;

    buff->ref_timestamp = aux_buffer->reference;

    return buff->len;
}

static void cs_etm__set_pid_tid_cpu(struct cs_etm_auxtrace *etm,
                    struct auxtrace_queue *queue)
{
    struct cs_etm_queue *etmq = queue->priv;

    /* CPU-wide tracing isn't supported yet */
    if (queue->tid == -1)
        return;

    if ((!etmq->thread) && (etmq->tid != -1))
        etmq->thread = machine__find_thread(etm->machine, -1,
                            etmq->tid);

    if (etmq->thread) {
        etmq->pid = etmq->thread->pid_;
        if (queue->cpu == -1)
            etmq->cpu = etmq->thread->cpu;
    }
}

static int cs_etm__synth_instruction_sample(struct cs_etm_queue *etmq,
                        u64 addr, u64 period)
{
    int ret = 0;
    struct cs_etm_auxtrace *etm = etmq->etm;
    union perf_event *event = etmq->event_buf;
    struct perf_sample sample = {.ip = 0,};

    event->sample.header.type = PERF_RECORD_SAMPLE;
    event->sample.header.misc = PERF_RECORD_MISC_USER;
    event->sample.header.size = sizeof(struct perf_event_header);

    sample.ip = addr;
    sample.pid = etmq->pid;
    sample.tid = etmq->tid;
    sample.id = etmq->etm->instructions_id;
    sample.stream_id = etmq->etm->instructions_id;
    sample.period = period;
    sample.cpu = etmq->packet->cpu;
    sample.flags = 0;
    sample.insn_len = 1;
    sample.cpumode = event->header.misc;

    if (etm->synth_opts.last_branch) {
        cs_etm__copy_last_branch_rb(etmq);
        sample.branch_stack = etmq->last_branch;
    }

    if (etm->synth_opts.inject) {
        ret = cs_etm__inject_event(event, &sample,
                       etm->instructions_sample_type);
        if (ret)
            return ret;
    }

    ret = perf_session__deliver_synth_event(etm->session, event, &sample);

    if (ret)
        pr_err(
            "CS ETM Trace: failed to deliver instruction event, error %d\n",
            ret);

    if (etm->synth_opts.last_branch)
        cs_etm__reset_last_branch_rb(etmq);

    return ret;
}

/*
 * The cs etm packet encodes an instruction range between a branch target
 * and the next taken branch. Generate sample accordingly.
 */
static int cs_etm__synth_branch_sample(struct cs_etm_queue *etmq)
{
    int ret = 0;
    struct cs_etm_auxtrace *etm = etmq->etm;
    struct perf_sample sample = {.ip = 0,};
    union perf_event *event = etmq->event_buf;
    struct dummy_branch_stack {
        u64         nr;
        struct branch_entry entries;
    } dummy_bs;

    event->sample.header.type = PERF_RECORD_SAMPLE;
    event->sample.header.misc = PERF_RECORD_MISC_USER;
    event->sample.header.size = sizeof(struct perf_event_header);

    sample.ip = cs_etm__last_executed_instr(etmq->prev_packet);
    sample.pid = etmq->pid;
    sample.tid = etmq->tid;
    sample.addr = etmq->packet->start_addr;
    sample.id = etmq->etm->branches_id;
    sample.stream_id = etmq->etm->branches_id;
    sample.period = 1;
    sample.cpu = etmq->packet->cpu;
    sample.flags = 0;
    sample.cpumode = PERF_RECORD_MISC_USER;

    /*
     * perf report cannot handle events without a branch stack
     */
    if (etm->synth_opts.last_branch) {
        dummy_bs = (struct dummy_branch_stack){
            .nr = 1,
            .entries = {
                .from = sample.ip,
                .to = sample.addr,
            },
        };
        sample.branch_stack = (struct branch_stack *)&dummy_bs;
    }

    if (etm->synth_opts.inject) {
        ret = cs_etm__inject_event(event, &sample,
                       etm->branches_sample_type);
        if (ret)
            return ret;
    }

    ret = perf_session__deliver_synth_event(etm->session, event, &sample);

    if (ret)
        pr_err(
        "CS ETM Trace: failed to deliver instruction event, error %d\n",
        ret);

    return ret;
}

struct cs_etm_synth {
    struct perf_tool dummy_tool;
    struct perf_session *session;
};

static int cs_etm__event_synth(struct perf_tool *tool,
                   union perf_event *event,
                   struct perf_sample *sample __maybe_unused,
                   struct machine *machine __maybe_unused)
{
    struct cs_etm_synth *cs_etm_synth =
              container_of(tool, struct cs_etm_synth, dummy_tool);

    return perf_session__deliver_synth_event(cs_etm_synth->session,
                         event, NULL);
}

static int cs_etm__synth_event(struct perf_session *session,
                   struct perf_event_attr *attr, u64 id)
{
    struct cs_etm_synth cs_etm_synth;

    memset(&cs_etm_synth, 0, sizeof(struct cs_etm_synth));
    cs_etm_synth.session = session;

    return perf_event__synthesize_attr(&cs_etm_synth.dummy_tool, attr, 1,
                       &id, cs_etm__event_synth);
}

static int cs_etm__synth_events(struct cs_etm_auxtrace *etm,
                struct perf_session *session)
{
    struct perf_evlist *evlist = session->evlist;
    struct perf_evsel *evsel;
    struct perf_event_attr attr;
    bool found = false;
    u64 id;
    int err;

    evlist__for_each_entry(evlist, evsel) {
        if (evsel->attr.type == etm->pmu_type) {
            found = true;
            break;
        }
    }

    if (!found) {
        pr_debug("No selected events with CoreSight Trace data\n");
        return 0;
    }

    memset(&attr, 0, sizeof(struct perf_event_attr));
    attr.size = sizeof(struct perf_event_attr);
    attr.type = PERF_TYPE_HARDWARE;
    attr.sample_type = evsel->attr.sample_type & PERF_SAMPLE_MASK;
    attr.sample_type |= PERF_SAMPLE_IP | PERF_SAMPLE_TID |
                PERF_SAMPLE_PERIOD;
    if (etm->timeless_decoding)
        attr.sample_type &= ~(u64)PERF_SAMPLE_TIME;
    else
        attr.sample_type |= PERF_SAMPLE_TIME;

    attr.exclude_user = evsel->attr.exclude_user;
    attr.exclude_kernel = evsel->attr.exclude_kernel;
    attr.exclude_hv = evsel->attr.exclude_hv;
    attr.exclude_host = evsel->attr.exclude_host;
    attr.exclude_guest = evsel->attr.exclude_guest;
    attr.sample_id_all = evsel->attr.sample_id_all;
    attr.read_format = evsel->attr.read_format;

    /* create new id val to be a fixed offset from evsel id */
    id = evsel->id[0] + 1000000000;

    if (!id)
        id = 1;

    if (etm->synth_opts.branches) {
        attr.config = PERF_COUNT_HW_BRANCH_INSTRUCTIONS;
        attr.sample_period = 1;
        attr.sample_type |= PERF_SAMPLE_ADDR;
        err = cs_etm__synth_event(session, &attr, id);
        if (err)
            return err;
        etm->sample_branches = true;
        etm->branches_sample_type = attr.sample_type;
        etm->branches_id = id;
        id += 1;
        attr.sample_type &= ~(u64)PERF_SAMPLE_ADDR;
    }

    if (etm->synth_opts.last_branch)
        attr.sample_type |= PERF_SAMPLE_BRANCH_STACK;

    if (etm->synth_opts.instructions) {
        attr.config = PERF_COUNT_HW_INSTRUCTIONS;
        attr.sample_period = etm->synth_opts.period;
        etm->instructions_sample_period = attr.sample_period;
        err = cs_etm__synth_event(session, &attr, id);
        if (err)
            return err;
        etm->sample_instructions = true;
        etm->instructions_sample_type = attr.sample_type;
        etm->instructions_id = id;
        id += 1;
    }

    return 0;
}

static int cs_etm__sample(struct cs_etm_queue *etmq)
{
    struct cs_etm_auxtrace *etm = etmq->etm;
    struct cs_etm_packet *tmp;
    int ret;
    u64 instrs_executed;

    instrs_executed = cs_etm__instr_count(etmq->packet);
    etmq->period_instructions += instrs_executed;

    /*
     * Record a branch when the last instruction in
     * PREV_PACKET is a branch.
     */
    if (etm->synth_opts.last_branch &&
        etmq->prev_packet &&
        etmq->prev_packet->sample_type == CS_ETM_RANGE &&
        etmq->prev_packet->last_instr_taken_branch)
        cs_etm__update_last_branch_rb(etmq);

    if (etm->sample_instructions &&
        etmq->period_instructions >= etm->instructions_sample_period) {
        /*
         * Emit instruction sample periodically
         * TODO: allow period to be defined in cycles and clock time
         */

        /* Get number of instructions executed after the sample point */
        u64 instrs_over = etmq->period_instructions -
            etm->instructions_sample_period;

        /*
         * Calculate the address of the sampled instruction (-1 as
         * sample is reported as though instruction has just been
         * executed, but PC has not advanced to next instruction)
         */
        u64 offset = (instrs_executed - instrs_over - 1);
        u64 addr = cs_etm__instr_addr(etmq->packet, offset);

        ret = cs_etm__synth_instruction_sample(
            etmq, addr, etm->instructions_sample_period);
        if (ret)
            return ret;

        /* Carry remaining instructions into next sample period */
        etmq->period_instructions = instrs_over;
    }

    if (etm->sample_branches &&
        etmq->prev_packet &&
        etmq->prev_packet->sample_type == CS_ETM_RANGE &&
        etmq->prev_packet->last_instr_taken_branch) {
        ret = cs_etm__synth_branch_sample(etmq);
        if (ret)
            return ret;
    }

    if (etm->sample_branches || etm->synth_opts.last_branch) {
        /*
         * Swap PACKET with PREV_PACKET: PACKET becomes PREV_PACKET for
         * the next incoming packet.
         */
        tmp = etmq->packet;
        etmq->packet = etmq->prev_packet;
        etmq->prev_packet = tmp;
    }

    return 0;
}

static int cs_etm__flush(struct cs_etm_queue *etmq)
{
    int err = 0;
    struct cs_etm_packet *tmp;

    if (etmq->etm->synth_opts.last_branch &&
        etmq->prev_packet &&
        etmq->prev_packet->sample_type == CS_ETM_RANGE) {
        /*
         * Generate a last branch event for the branches left in the
         * circular buffer at the end of the trace.
         *
         * Use the address of the end of the last reported execution
         * range
         */
        u64 addr = cs_etm__last_executed_instr(etmq->prev_packet);

        err = cs_etm__synth_instruction_sample(
            etmq, addr,
            etmq->period_instructions);
        etmq->period_instructions = 0;

        /*
         * Swap PACKET with PREV_PACKET: PACKET becomes PREV_PACKET for
         * the next incoming packet.
         */
        tmp = etmq->packet;
        etmq->packet = etmq->prev_packet;
        etmq->prev_packet = tmp;
    }

    return err;
}

static int cs_etm__run_decoder(struct cs_etm_queue *etmq)
{
    struct cs_etm_auxtrace *etm = etmq->etm;
    struct cs_etm_buffer buffer;
    size_t buffer_used, processed;
    int err = 0;

    if (!etm->kernel_start)
        etm->kernel_start = machine__kernel_start(etm->machine);

    /* Go through each buffer in the queue and decode them one by one */
    while (1) {
        buffer_used = 0;
        memset(&buffer, 0, sizeof(buffer));
        err = cs_etm__get_trace(&buffer, etmq);
        if (err <= 0)
            return err;
        /*
         * We cannot assume consecutive blocks in the data file are
         * contiguous, reset the decoder to force re-sync.
         */
        err = cs_etm_decoder__reset(etmq->decoder);
        if (err != 0)
            return err;

        /* Run trace decoder until buffer consumed or end of trace */
        do {
            processed = 0;
            err = cs_etm_decoder__process_data_block(
                etmq->decoder,
                etmq->offset,
                &buffer.buf[buffer_used],
                buffer.len - buffer_used,
                &processed);
            if (err)
                return err;

            etmq->offset += processed;
            buffer_used += processed;

            /* Process each packet in this chunk */
            while (1) {
                err = cs_etm_decoder__get_packet(etmq->decoder,
                                 etmq->packet);
                if (err <= 0)
                    /*
                     * Stop processing this chunk on
                     * end of data or error
                     */
                    break;

                switch (etmq->packet->sample_type) {
                case CS_ETM_RANGE:
                    /*
                     * If the packet contains an instruction
                     * range, generate instruction sequence
                     * events.
                     */
                    cs_etm__sample(etmq);
                    break;
                case CS_ETM_TRACE_ON:
                    /*
                     * Discontinuity in trace, flush
                     * previous branch stack
                     */
                    cs_etm__flush(etmq);
                    break;
                default:
                    break;
                }
            }
        } while (buffer.len > buffer_used);

        if (err == 0)
            /* Flush any remaining branch stack entries */
            err = cs_etm__flush(etmq);
    }

    return err;
}

static int cs_etm__process_timeless_queues(struct cs_etm_auxtrace *etm,
                       pid_t tid, u64 time_)
{
    unsigned int i;
    struct auxtrace_queues *queues = &etm->queues;

    for (i = 0; i < queues->nr_queues; i++) {
        struct auxtrace_queue *queue = &etm->queues.queue_array[i];
        struct cs_etm_queue *etmq = queue->priv;

        if (etmq && ((tid == -1) || (etmq->tid == tid))) {
            etmq->time = time_;
            cs_etm__set_pid_tid_cpu(etm, queue);
            cs_etm__run_decoder(etmq);
        }
    }

    return 0;
}

static int cs_etm__process_event(struct perf_session *session,
                 union perf_event *event,
                 struct perf_sample *sample,
                 struct perf_tool *tool)
{
    int err = 0;
    u64 timestamp;
    struct cs_etm_auxtrace *etm = container_of(session->auxtrace,
                           struct cs_etm_auxtrace,
                           auxtrace);

    if (dump_trace)
        return 0;

    if (!tool->ordered_events) {
        pr_err("CoreSight ETM Trace requires ordered events\n");
        return -EINVAL;
    }

    if (!etm->timeless_decoding)
        return -EINVAL;

    if (sample->time && (sample->time != (u64) -1))
        timestamp = sample->time;
    else
        timestamp = 0;

    if (timestamp || etm->timeless_decoding) {
        err = cs_etm__update_queues(etm);
        if (err)
            return err;
    }

    if (event->header.type == PERF_RECORD_EXIT)
        return cs_etm__process_timeless_queues(etm,
                               event->fork.tid,
                               sample->time);

    return 0;
}

static int cs_etm__process_auxtrace_event(struct perf_session *session,
                      union perf_event *event,
                      struct perf_tool *tool __maybe_unused)
{
    struct cs_etm_auxtrace *etm = container_of(session->auxtrace,
                           struct cs_etm_auxtrace,
                           auxtrace);
    if (!etm->data_queued) {
        struct auxtrace_buffer *buffer;
        off_t  data_offset;
        int fd = perf_data__fd(session->data);
        bool is_pipe = perf_data__is_pipe(session->data);
        int err;

        if (is_pipe)
            data_offset = 0;
        else {
            data_offset = lseek(fd, 0, SEEK_CUR);
            if (data_offset == -1)
                return -errno;
        }

        err = auxtrace_queues__add_event(&etm->queues, session,
                         event, data_offset, &buffer);
        if (err)
            return err;

        if (dump_trace)
            if (auxtrace_buffer__get_data(buffer, fd)) {
                cs_etm__dump_event(etm, buffer);
                auxtrace_buffer__put_data(buffer);
            }
    }

    return 0;
}

static bool cs_etm__is_timeless_decoding(struct cs_etm_auxtrace *etm)
{
    struct perf_evsel *evsel;
    struct perf_evlist *evlist = etm->session->evlist;
    bool timeless_decoding = true;

    /*
     * Circle through the list of event and complain if we find one
     * with the time bit set.
     */
    evlist__for_each_entry(evlist, evsel) {
        if ((evsel->attr.sample_type & PERF_SAMPLE_TIME))
            timeless_decoding = false;
    }

    return timeless_decoding;
}

static const char * const cs_etm_global_header_fmts[] = {
    [CS_HEADER_VERSION_0]   = " Header version             %llx\n",
    [CS_PMU_TYPE_CPUS]  = " PMU type/num cpus          %llx\n",
    [CS_ETM_SNAPSHOT]   = " Snapshot               %llx\n",
};

static const char * const cs_etm_priv_fmts[] = {
    [CS_ETM_MAGIC]      = " Magic number               %llx\n",
    [CS_ETM_CPU]        = " CPU                %lld\n",
    [CS_ETM_ETMCR]      = " ETMCR                  %llx\n",
    [CS_ETM_ETMTRACEIDR]    = " ETMTRACEIDR            %llx\n",
    [CS_ETM_ETMCCER]    = " ETMCCER                %llx\n",
    [CS_ETM_ETMIDR]     = " ETMIDR                 %llx\n",
};

static const char * const cs_etmv4_priv_fmts[] = {
    [CS_ETM_MAGIC]      = " Magic number               %llx\n",
    [CS_ETM_CPU]        = " CPU                %lld\n",
    [CS_ETMV4_TRCCONFIGR]   = " TRCCONFIGR             %llx\n",
    [CS_ETMV4_TRCTRACEIDR]  = " TRCTRACEIDR            %llx\n",
    [CS_ETMV4_TRCIDR0]  = " TRCIDR0                %llx\n",
    [CS_ETMV4_TRCIDR1]  = " TRCIDR1                %llx\n",
    [CS_ETMV4_TRCIDR2]  = " TRCIDR2                %llx\n",
    [CS_ETMV4_TRCIDR8]  = " TRCIDR8                %llx\n",
    [CS_ETMV4_TRCAUTHSTATUS] = "    TRCAUTHSTATUS              %llx\n",
};

static void cs_etm__print_auxtrace_info(u64 *val, int num)
{
    int i, j, cpu = 0;

    for (i = 0; i < CS_HEADER_VERSION_0_MAX; i++)
        fprintf(stdout, cs_etm_global_header_fmts[i], val[i]);

    for (i = CS_HEADER_VERSION_0_MAX; cpu < num; cpu++) {
        if (val[i] == __perf_cs_etmv3_magic)
            for (j = 0; j < CS_ETM_PRIV_MAX; j++, i++)
                fprintf(stdout, cs_etm_priv_fmts[j], val[i]);
        else if (val[i] == __perf_cs_etmv4_magic)
            for (j = 0; j < CS_ETMV4_PRIV_MAX; j++, i++)
                fprintf(stdout, cs_etmv4_priv_fmts[j], val[i]);
        else
            /* failure.. return */
            return;
    }
}

int cs_etm__process_auxtrace_info(union perf_event *event,
                  struct perf_session *session)
{
    struct auxtrace_info_event *auxtrace_info = &event->auxtrace_info;
    struct cs_etm_auxtrace *etm = NULL;
    struct int_node *inode;
    unsigned int pmu_type;
    int event_header_size = sizeof(struct perf_event_header);
    int info_header_size;
    int total_size = auxtrace_info->header.size;
    int priv_size = 0;
    int num_cpu;
    int err = 0, idx = -1;
    int i, j, k;
    u64 *ptr, *hdr = NULL;
    u64 **metadata = NULL;

    /*
     * sizeof(auxtrace_info_event::type) +
     * sizeof(auxtrace_info_event::reserved) == 8
     */
    info_header_size = 8;

    if (total_size < (event_header_size + info_header_size))
        return -EINVAL;

    priv_size = total_size - event_header_size - info_header_size;

    /* First the global part */
    ptr = (u64 *) auxtrace_info->priv;

    /* Look for version '0' of the header */
    if (ptr[0] != 0)
        return -EINVAL;

    hdr = zalloc(sizeof(*hdr) * CS_HEADER_VERSION_0_MAX);
    if (!hdr)
        return -ENOMEM;

    /* Extract header information - see cs-etm.h for format */
    for (i = 0; i < CS_HEADER_VERSION_0_MAX; i++)
        hdr[i] = ptr[i];
    num_cpu = hdr[CS_PMU_TYPE_CPUS] & 0xffffffff;
    pmu_type = (unsigned int) ((hdr[CS_PMU_TYPE_CPUS] >> 32) &
                    0xffffffff);

    /*
     * Create an RB tree for traceID-CPU# tuple. Since the conversion has
     * to be made for each packet that gets decoded, optimizing access in
     * anything other than a sequential array is worth doing.
     */
    traceid_list = intlist__new(NULL);
    if (!traceid_list) {
        err = -ENOMEM;
        goto err_free_hdr;
    }

    metadata = zalloc(sizeof(*metadata) * num_cpu);
    if (!metadata) {
        err = -ENOMEM;
        goto err_free_traceid_list;
    }

    /*
     * The metadata is stored in the auxtrace_info section and encodes
     * the configuration of the ARM embedded trace macrocell which is
     * required by the trace decoder to properly decode the trace due
     * to its highly compressed nature.
     */
    for (j = 0; j < num_cpu; j++) {
        if (ptr[i] == __perf_cs_etmv3_magic) {
            metadata[j] = zalloc(sizeof(*metadata[j]) *
                         CS_ETM_PRIV_MAX);
            if (!metadata[j]) {
                err = -ENOMEM;
                goto err_free_metadata;
            }
            for (k = 0; k < CS_ETM_PRIV_MAX; k++)
                metadata[j][k] = ptr[i + k];

            /* The traceID is our handle */
            idx = metadata[j][CS_ETM_ETMTRACEIDR];
            i += CS_ETM_PRIV_MAX;
        } else if (ptr[i] == __perf_cs_etmv4_magic) {
            metadata[j] = zalloc(sizeof(*metadata[j]) *
                         CS_ETMV4_PRIV_MAX);
            if (!metadata[j]) {
                err = -ENOMEM;
                goto err_free_metadata;
            }
            for (k = 0; k < CS_ETMV4_PRIV_MAX; k++)
                metadata[j][k] = ptr[i + k];

            /* The traceID is our handle */
            idx = metadata[j][CS_ETMV4_TRCTRACEIDR];
            i += CS_ETMV4_PRIV_MAX;
        }

        /* Get an RB node for this CPU */
        inode = intlist__findnew(traceid_list, idx);

        /* Something went wrong, no need to continue */
        if (!inode) {
            err = PTR_ERR(inode);
            goto err_free_metadata;
        }

        /*
         * The node for that CPU should not be taken.
         * Back out if that's the case.
         */
        if (inode->priv) {
            err = -EINVAL;
            goto err_free_metadata;
        }
        /* All good, associate the traceID with the CPU# */
        inode->priv = &metadata[j][CS_ETM_CPU];
    }

    /*
     * Each of CS_HEADER_VERSION_0_MAX, CS_ETM_PRIV_MAX and
     * CS_ETMV4_PRIV_MAX mark how many double words are in the
     * global metadata, and each cpu's metadata respectively.
     * The following tests if the correct number of double words was
     * present in the auxtrace info section.
     */
    if (i * 8 != priv_size) {
        err = -EINVAL;
        goto err_free_metadata;
    }

    etm = zalloc(sizeof(*etm));

    if (!etm) {
        err = -ENOMEM;
        goto err_free_metadata;
    }

    err = auxtrace_queues__init(&etm->queues);
    if (err)
        goto err_free_etm;

    etm->session = session;
    etm->machine = &session->machines.host;

    etm->num_cpu = num_cpu;
    etm->pmu_type = pmu_type;
    etm->snapshot_mode = (hdr[CS_ETM_SNAPSHOT] != 0);
    etm->metadata = metadata;
    etm->auxtrace_type = auxtrace_info->type;
    etm->timeless_decoding = cs_etm__is_timeless_decoding(etm);

    etm->auxtrace.process_event = cs_etm__process_event;
    etm->auxtrace.process_auxtrace_event = cs_etm__process_auxtrace_event;
    etm->auxtrace.flush_events = cs_etm__flush_events;
    etm->auxtrace.free_events = cs_etm__free_events;
    etm->auxtrace.free = cs_etm__free;
    session->auxtrace = &etm->auxtrace;

    etm->unknown_thread = thread__new(999999999, 999999999);
    if (!etm->unknown_thread)
        goto err_free_queues;

    /*
     * Initialize list node so that at thread__zput() we can avoid
     * segmentation fault at list_del_init().
     */
    INIT_LIST_HEAD(&etm->unknown_thread->node);

    err = thread__set_comm(etm->unknown_thread, "unknown", 0);
    if (err)
        goto err_delete_thread;

    if (thread__init_map_groups(etm->unknown_thread, etm->machine))
        goto err_delete_thread;

    if (dump_trace) {
        cs_etm__print_auxtrace_info(auxtrace_info->priv, num_cpu);
        return 0;
    }

    if (session->itrace_synth_opts && session->itrace_synth_opts->set) {
        etm->synth_opts = *session->itrace_synth_opts;
    } else {
        itrace_synth_opts__set_default(&etm->synth_opts);
        etm->synth_opts.callchain = false;
    }

    err = cs_etm__synth_events(etm, session);
    if (err)
        goto err_delete_thread;

    err = auxtrace_queues__process_index(&etm->queues, session);
    if (err)
        goto err_delete_thread;

    etm->data_queued = etm->queues.populated;

    return 0;

err_delete_thread:
    thread__zput(etm->unknown_thread);
err_free_queues:
    auxtrace_queues__free(&etm->queues);
    session->auxtrace = NULL;
err_free_etm:
    zfree(&etm);
err_free_metadata:
    /* No need to check @metadata[j], free(NULL) is supported */
    for (j = 0; j < num_cpu; j++)
        free(metadata[j]);
    zfree(&metadata);
err_free_traceid_list:
    intlist__delete(traceid_list);
err_free_hdr:
    zfree(&hdr);

    return -EINVAL;
}