CoreSight has supported the thread stack; so based on the thread stack
we can synthesize call chain for the instruction sample; the call chain
can be used by itrace option '--itrace=g'.

Before:

  # perf script --itrace=g16l64i100
            main  1579        100      instructions:  ffff0000102137f0 
group_sched_in+0xb0 ([kernel.kallsyms])
            main  1579        100      instructions:  ffff000010213b78 
flexible_sched_in+0xf0 ([kernel.kallsyms])
            main  1579        100      instructions:  ffff0000102135ac 
event_sched_in.isra.57+0x74 ([kernel.kallsyms])
            main  1579        100      instructions:  ffff000010219344 
perf_swevent_add+0x6c ([kernel.kallsyms])
            main  1579        100      instructions:  ffff000010214854 
perf_event_update_userpage+0x4c ([kernel.kallsyms])
  [...]

After:

  # perf script --itrace=g16l64i100

  main  1579        100      instructions:
          ffff000010213b78 flexible_sched_in+0xf0 ([kernel.kallsyms])
          ffff00001020c0b4 visit_groups_merge+0x12c ([kernel.kallsyms])

  main  1579        100      instructions:
          ffff0000102135ac event_sched_in.isra.57+0x74 ([kernel.kallsyms])
          ffff0000102137a0 group_sched_in+0x60 ([kernel.kallsyms])
          ffff000010213b84 flexible_sched_in+0xfc ([kernel.kallsyms])
          ffff00001020c0b4 visit_groups_merge+0x12c ([kernel.kallsyms])

  main  1579        100      instructions:
          ffff000010219344 perf_swevent_add+0x6c ([kernel.kallsyms])
          ffff0000102135f4 event_sched_in.isra.57+0xbc ([kernel.kallsyms])
          ffff0000102137a0 group_sched_in+0x60 ([kernel.kallsyms])
          ffff000010213b84 flexible_sched_in+0xfc ([kernel.kallsyms])
          ffff00001020c0b4 visit_groups_merge+0x12c ([kernel.kallsyms])
  [...]

Signed-off-by: Leo Yan <leo....@linaro.org>
---
 tools/perf/util/cs-etm.c | 35 +++++++++++++++++++++++++++++++++--
 1 file changed, 33 insertions(+), 2 deletions(-)

diff --git a/tools/perf/util/cs-etm.c b/tools/perf/util/cs-etm.c
index 018c7e682ded..bd09254a7208 100644
--- a/tools/perf/util/cs-etm.c
+++ b/tools/perf/util/cs-etm.c
@@ -17,6 +17,7 @@
 #include <stdlib.h>
 
 #include "auxtrace.h"
+#include "callchain.h"
 #include "color.h"
 #include "cs-etm.h"
 #include "cs-etm-decoder/cs-etm-decoder.h"
@@ -73,6 +74,7 @@ struct cs_etm_traceid_queue {
        size_t last_branch_pos;
        union perf_event *event_buf;
        struct thread *thread;
+       struct ip_callchain *chain;
        struct branch_stack *last_branch;
        struct branch_stack *last_branch_rb;
        struct cs_etm_packet *prev_packet;
@@ -250,6 +252,16 @@ static int cs_etm__init_traceid_queue(struct cs_etm_queue 
*etmq,
        if (!tidq->prev_packet)
                goto out_free;
 
+       if (etm->synth_opts.callchain) {
+               size_t sz = sizeof(struct ip_callchain);
+
+               /* Add 1 to callchain_sz for callchain context */
+               sz += (etm->synth_opts.callchain_sz + 1) * sizeof(u64);
+               tidq->chain = zalloc(sz);
+               if (!tidq->chain)
+                       goto out_free;
+       }
+
        if (etm->synth_opts.last_branch) {
                size_t sz = sizeof(struct branch_stack);
 
@@ -274,6 +286,7 @@ static int cs_etm__init_traceid_queue(struct cs_etm_queue 
*etmq,
        zfree(&tidq->last_branch);
        zfree(&tidq->prev_packet);
        zfree(&tidq->packet);
+       zfree(&tidq->chain);
 out:
        return rc;
 }
@@ -545,6 +558,7 @@ static void cs_etm__free_traceid_queues(struct cs_etm_queue 
*etmq)
                zfree(&tidq->last_branch_rb);
                zfree(&tidq->prev_packet);
                zfree(&tidq->packet);
+               zfree(&tidq->chain);
                zfree(&tidq);
 
                /*
@@ -1125,7 +1139,7 @@ static void cs_etm__add_stack_event(struct cs_etm_queue 
*etmq,
        int insn_len;
        u64 from_ip, to_ip;
 
-       if (etm->synth_opts.thread_stack) {
+       if (etm->synth_opts.callchain || etm->synth_opts.thread_stack) {
                from_ip = cs_etm__last_executed_instr(tidq->prev_packet);
                to_ip = cs_etm__first_executed_instr(tidq->packet);
 
@@ -1181,6 +1195,14 @@ static int cs_etm__synth_instruction_sample(struct 
cs_etm_queue *etmq,
 
        cs_etm__copy_insn(etmq, tidq->trace_chan_id, tidq->packet, &sample);
 
+       if (etm->synth_opts.callchain) {
+               thread_stack__sample(tidq->thread, tidq->packet->cpu,
+                                    tidq->chain,
+                                    etm->synth_opts.callchain_sz + 1,
+                                    sample.ip, etm->kernel_start);
+               sample.callchain = tidq->chain;
+       }
+
        if (etm->synth_opts.last_branch) {
                cs_etm__copy_last_branch_rb(etmq, tidq);
                sample.branch_stack = tidq->last_branch;
@@ -1368,6 +1390,8 @@ static int cs_etm__synth_events(struct cs_etm_auxtrace 
*etm,
                attr.sample_type &= ~(u64)PERF_SAMPLE_ADDR;
        }
 
+       if (etm->synth_opts.callchain)
+               attr.sample_type |= PERF_SAMPLE_CALLCHAIN;
        if (etm->synth_opts.last_branch)
                attr.sample_type |= PERF_SAMPLE_BRANCH_STACK;
 
@@ -2638,7 +2662,6 @@ int cs_etm__process_auxtrace_info(union perf_event *event,
        } else {
                itrace_synth_opts__set_default(&etm->synth_opts,
                                session->itrace_synth_opts->default_no_sample);
-               etm->synth_opts.callchain = false;
                etm->synth_opts.thread_stack =
                                session->itrace_synth_opts->thread_stack;
        }
@@ -2650,6 +2673,14 @@ int cs_etm__process_auxtrace_info(union perf_event 
*event,
                etm->branches_filter |= PERF_IP_FLAG_RETURN |
                                        PERF_IP_FLAG_TRACE_BEGIN;
 
+       if (etm->synth_opts.callchain && !symbol_conf.use_callchain) {
+               symbol_conf.use_callchain = true;
+               if (callchain_register_param(&callchain_param) < 0) {
+                       symbol_conf.use_callchain = false;
+                       etm->synth_opts.callchain = false;
+               }
+       }
+
        err = cs_etm__synth_events(etm, session);
        if (err)
                goto err_delete_thread;
-- 
2.17.1

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