perf bpf: Generalize bpf__setup_stdout()

We will use it to set up other bpf-output events, for instance to
generate augmented syscall entry tracepoints with pointer contents.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: https://lkml.kernel.org/n/tip-4r7kw0nsyi4vyz6xm1tzx6a3@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

2 files changed, 24 insertions, 9 deletions

diff --git a/tools/perf/util/bpf-loader.c b/tools/perf/util/bpf-loader.c
index e864a7e0ff12..95a27bb6f1a1 100644
--- a/tools/perf/util/bpf-loader.c
+++ b/tools/perf/util/bpf-loader.c
@@ -1535,10 +1535,7 @@ int bpf__apply_obj_config(void)
                         (strcmp(name,                   \
                                 bpf_map__name(pos)) == 0))
 
-#define bpf__for_each_stdout_map(pos, obj, objtmp) \
-         bpf__for_each_map_named(pos, obj, objtmp, "__bpf_stdout__")
-
-int bpf__setup_stdout(struct perf_evlist *evlist)
+int bpf__setup_output_event(struct perf_evlist *evlist, const char *name)
 {
         struct bpf_map_priv *tmpl_priv = NULL;
         struct bpf_object *obj, *tmp;
@@ -1547,7 +1544,7 @@ int bpf__setup_stdout(struct perf_evlist *evlist)
         int err;
         bool need_init = false;
 
-        bpf__for_each_stdout_map(map, obj, tmp) {
+        bpf__for_each_map_named(map, obj, tmp, name) {
                 struct bpf_map_priv *priv = bpf_map__priv(map);
 
                 if (IS_ERR(priv))
@@ -1567,17 +1564,23 @@ int bpf__setup_stdout(struct perf_evlist *evlist)
                 return 0;
 
         if (!tmpl_priv) {
-                err = parse_events(evlist, "bpf-output/no-inherit=1,name=__bpf_stdout__/",
-                                   NULL);
+                char *event_definition = NULL;
+
+                if (asprintf(&event_definition, "bpf-output/no-inherit=1,name=%s/", name) < 0)
+                        return -ENOMEM;
+
+                err = parse_events(evlist, event_definition, NULL);
+                free(event_definition);
+
                 if (err) {
-                        pr_debug("ERROR: failed to create bpf-output event\n");
+                        pr_debug("ERROR: failed to create the \"%s\" bpf-output event\n", name);
                         return -err;
                 }
 
                 evsel = perf_evlist__last(evlist);
         }
 
-        bpf__for_each_stdout_map(map, obj, tmp) {
+        bpf__for_each_map_named(map, obj, tmp, name) {
                 struct bpf_map_priv *priv = bpf_map__priv(map);
 
                 if (IS_ERR(priv))
@@ -1609,6 +1612,11 @@ int bpf__setup_stdout(struct perf_evlist *evlist)
         return 0;
 }
 
+int bpf__setup_stdout(struct perf_evlist *evlist)
+{
+        return bpf__setup_output_event(evlist, "__bpf_stdout__");
+}
+
 #define ERRNO_OFFSET(e)         ((e) - __BPF_LOADER_ERRNO__START)
 #define ERRCODE_OFFSET(c)       ERRNO_OFFSET(BPF_LOADER_ERRNO__##c)
 #define NR_ERRNO        (__BPF_LOADER_ERRNO__END - __BPF_LOADER_ERRNO__START)
diff --git a/tools/perf/util/bpf-loader.h b/tools/perf/util/bpf-loader.h
index 5d3aefd6fae7..6be0eec043c6 100644
--- a/tools/perf/util/bpf-loader.h
+++ b/tools/perf/util/bpf-loader.h
@@ -82,6 +82,7 @@ int bpf__apply_obj_config(void);
 int bpf__strerror_apply_obj_config(int err, char *buf, size_t size);
 
 int bpf__setup_stdout(struct perf_evlist *evlist);
+int bpf__setup_output_event(struct perf_evlist *evlist, const char *name);
 int bpf__strerror_setup_stdout(struct perf_evlist *evlist, int err,
                                char *buf, size_t size);
 
@@ -139,6 +140,12 @@ bpf__setup_stdout(struct perf_evlist *evlist __maybe_unused)
 }
 
 static inline int
+bpf__setup_output_event(struct perf_evlist *evlist __maybe_unused, const char *name __maybe_unused)
+{
+        return 0;
+}
+
+static inline int
 __bpf_strerror(char *buf, size_t size)
 {
         if (!size)