From 32bfa5bf71db672c646751da131a17aace8cceac Mon Sep 17 00:00:00 2001 From: Alexandre Truong Date: Fri, 17 Dec 2021 15:45:16 +0000 Subject: [PATCH] perf machine: Add a mechanism to inject stack frames Add a mechanism for platforms to inject stack frames for the leaf frame caller if there is enough information to determine a frame is missing from dwarf or other post processing mechanisms. Reviewed-by: James Clark Signed-off-by: Alexandre Truong Acked-by: Jiri Olsa Cc: Alexander Shishkin Cc: John Garry Cc: Leo Yan Cc: Mark Rutland Cc: Mathieu Poirier Cc: Namhyung Kim Cc: Will Deacon Cc: linux-arm-kernel@lists.infradead.org Link: https://lore.kernel.org/r/20211217154521.80603-3-german.gomez@arm.com Signed-off-by: German Gomez Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/util/machine.c | 37 ++++++++++++++++++++++++++++++++++++- 1 file changed, 36 insertions(+), 1 deletion(-) diff --git a/tools/perf/util/machine.c b/tools/perf/util/machine.c index fb8496df8432..3eddad009f78 100644 --- a/tools/perf/util/machine.c +++ b/tools/perf/util/machine.c @@ -2710,6 +2710,12 @@ static int find_prev_cpumode(struct ip_callchain *chain, struct thread *thread, return err; } +static u64 get_leaf_frame_caller(struct perf_sample *sample __maybe_unused, + struct thread *thread __maybe_unused, int usr_idx __maybe_unused) +{ + return 0; +} + static int thread__resolve_callchain_sample(struct thread *thread, struct callchain_cursor *cursor, struct evsel *evsel, @@ -2723,9 +2729,10 @@ static int thread__resolve_callchain_sample(struct thread *thread, struct ip_callchain *chain = sample->callchain; int chain_nr = 0; u8 cpumode = PERF_RECORD_MISC_USER; - int i, j, err, nr_entries; + int i, j, err, nr_entries, usr_idx; int skip_idx = -1; int first_call = 0; + u64 leaf_frame_caller; if (chain) chain_nr = chain->nr; @@ -2850,6 +2857,34 @@ check_calls: continue; } + /* + * PERF_CONTEXT_USER allows us to locate where the user stack ends. + * Depending on callchain_param.order and the position of PERF_CONTEXT_USER, + * the index will be different in order to add the missing frame + * at the right place. + */ + + usr_idx = callchain_param.order == ORDER_CALLEE ? j-2 : j-1; + + if (usr_idx >= 0 && chain->ips[usr_idx] == PERF_CONTEXT_USER) { + + leaf_frame_caller = get_leaf_frame_caller(sample, thread, usr_idx); + + /* + * check if leaf_frame_Caller != ip to not add the same + * value twice. + */ + + if (leaf_frame_caller && leaf_frame_caller != ip) { + + err = add_callchain_ip(thread, cursor, parent, + root_al, &cpumode, leaf_frame_caller, + false, NULL, NULL, 0); + if (err) + return (err < 0) ? err : 0; + } + } + err = add_callchain_ip(thread, cursor, parent, root_al, &cpumode, ip, false, NULL, NULL, 0); -- 2.11.0