perf tp_pmu: Add event APIs

Add event APIs for the tracepoint PMU allowing things like perf list
to function using it. For perf list add the tracepoint format in the
long description (shown with -v).

  $ sudo perf list -v tracepoint

  List of pre-defined events (to be used in -e or -M):

    alarmtimer:alarmtimer_cancel                       [Tracepoint event]
         [name: alarmtimer_cancel
          ID: 416
          format:
          field:unsigned short common_type; offset:0; size:2; signed:0;
          field:unsigned char common_flags; offset:2; size:1; signed:0;
          field:unsigned char common_preempt_count; offset:3; size:1; signed:0;
          field:int common_pid; offset:4; size:4; signed:1;
          field:void * alarm; offset:8; size:8; signed:0;
          field:unsigned char alarm_type; offset:16; size:1; signed:0;
          field:s64 expires; offset:24; size:8; signed:1;
          field:s64 now; offset:32; size:8; signed:1;
          print fmt: "alarmtimer:%p type:%s expires:%llu now:%llu",REC->alarm,__print_flags((1 << REC->alarm_type)," | ",{ 1 << 0,
          "REALTIME" },{ 1 << 1,"BOOTTIME" },{ 1 << 3,"REALTIME Freezer" },{ 1 << 4,"BOOTTIME Freezer" }),REC->expires,REC->now
          . Unit: tracepoint]
    alarmtimer:alarmtimer_fired                        [Tracepoint event]
         [name: alarmtimer_fired
          ID: 418
          ...

Signed-off-by: Ian Rogers <[email protected]>
Tested-by: Arnaldo Carvalho de Melo <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Namhyung Kim <[email protected]>

Author: captain5050

tools/perf/util/pmu.c

@@ -24,6 +24,7 @@
 #include "hwmon_pmu.h"
 #include "pmus.h"
 #include "tool_pmu.h"
+#include "tp_pmu.h"
 #include <util/pmu-bison.h>
 #include <util/pmu-flex.h>
 #include "parse-events.h"
@@ -1983,6 +1984,8 @@ bool perf_pmu__have_event(struct perf_pmu *pmu, const char *name)
 		return false;
 	if (perf_pmu__is_tool(pmu) && tool_pmu__skip_event(name))
 		return false;
+	if (perf_pmu__is_tracepoint(pmu))
+		return tp_pmu__have_event(pmu, name);
 	if (perf_pmu__is_hwmon(pmu))
 		return hwmon_pmu__have_event(pmu, name);
 	if (perf_pmu__is_drm(pmu))
@@ -1998,6 +2001,8 @@ size_t perf_pmu__num_events(struct perf_pmu *pmu)
 {
 	size_t nr;
 
+	if (perf_pmu__is_tracepoint(pmu))
+		return tp_pmu__num_events(pmu);
 	if (perf_pmu__is_hwmon(pmu))
 		return hwmon_pmu__num_events(pmu);
 	if (perf_pmu__is_drm(pmu))
@@ -2068,6 +2073,8 @@ int perf_pmu__for_each_event(struct perf_pmu *pmu, bool skip_duplicate_pmus,
 	struct hashmap_entry *entry;
 	size_t bkt;
 
+	if (perf_pmu__is_tracepoint(pmu))
+		return tp_pmu__for_each_event(pmu, state, cb);
 	if (perf_pmu__is_hwmon(pmu))
 		return hwmon_pmu__for_each_event(pmu, state, cb);
 	if (perf_pmu__is_drm(pmu))

tools/perf/util/tp_pmu.c

@@ -1,5 +1,6 @@
 // SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause)
 #include "tp_pmu.h"
+#include "pmus.h"
 #include <api/fs/fs.h>
 #include <api/fs/tracing_path.h>
 #include <api/io_dir.h>
@@ -93,3 +94,117 @@ int tp_pmu__for_each_tp_sys(void *state, tp_sys_callback cb)
 	close(events_dir.dirfd);
 	return ret;
 }
+
+bool perf_pmu__is_tracepoint(const struct perf_pmu *pmu)
+{
+	return pmu->type == PERF_TYPE_TRACEPOINT;
+}
+
+struct for_each_event_args {
+	void *state;
+	pmu_event_callback cb;
+	const struct perf_pmu *pmu;
+};
+
+static int for_each_event_cb(void *state, const char *sys_name, const char *evt_name)
+{
+	struct for_each_event_args *args = state;
+	char name[2 * FILENAME_MAX + 2];
+	/* 16 possible hex digits and 22 other characters and \0. */
+	char encoding[16 + 22];
+	char *format = NULL;
+	size_t format_size;
+	struct pmu_event_info info = {
+		.pmu = args->pmu,
+		.pmu_name = args->pmu->name,
+		.event_type_desc = "Tracepoint event",
+	};
+	char *tp_dir = get_events_file(sys_name);
+	char path[PATH_MAX];
+	int id, err;
+
+	if (!tp_dir)
+		return -1;
+
+	scnprintf(path, sizeof(path), "%s/%s/id", tp_dir, evt_name);
+	err = filename__read_int(path, &id);
+	if (err == 0) {
+		snprintf(encoding, sizeof(encoding), "tracepoint/config=0x%x/", id);
+		info.encoding_desc = encoding;
+	}
+
+	scnprintf(path, sizeof(path), "%s/%s/format", tp_dir, evt_name);
+	put_events_file(tp_dir);
+	err = filename__read_str(path, &format, &format_size);
+	if (err == 0) {
+		info.long_desc = format;
+		for (size_t i = 0 ; i < format_size; i++) {
+			/* Swap tabs to spaces due to some rendering issues. */
+			if (format[i] == '\t')
+				format[i] = ' ';
+		}
+	}
+	snprintf(name, sizeof(name), "%s:%s", sys_name, evt_name);
+	info.name = name;
+	err = args->cb(args->state, &info);
+	free(format);
+	return err;
+}
+
+static int for_each_event_sys_cb(void *state, const char *sys_name)
+{
+	return tp_pmu__for_each_tp_event(sys_name, state, for_each_event_cb);
+}
+
+int tp_pmu__for_each_event(struct perf_pmu *pmu, void *state, pmu_event_callback cb)
+{
+	struct for_each_event_args args = {
+		.state = state,
+		.cb = cb,
+		.pmu = pmu,
+	};
+
+	return tp_pmu__for_each_tp_sys(&args, for_each_event_sys_cb);
+}
+
+static int num_events_cb(void *state, const char *sys_name __maybe_unused,
+			 const char *evt_name __maybe_unused)
+{
+	size_t *count = state;
+
+	(*count)++;
+	return 0;
+}
+
+static int num_events_sys_cb(void *state, const char *sys_name)
+{
+	return tp_pmu__for_each_tp_event(sys_name, state, num_events_cb);
+}
+
+size_t tp_pmu__num_events(struct perf_pmu *pmu __maybe_unused)
+{
+	size_t count = 0;
+
+	tp_pmu__for_each_tp_sys(&count, num_events_sys_cb);
+	return count;
+}
+
+bool tp_pmu__have_event(struct perf_pmu *pmu __maybe_unused, const char *name)
+{
+	char *dup_name, *colon;
+	int id;
+
+	colon = strchr(name, ':');
+	if (colon == NULL)
+		return false;
+
+	dup_name = strdup(name);
+	if (!dup_name)
+		return false;
+
+	colon = dup_name + (colon - name);
+	*colon = '\0';
+	id = tp_pmu__id(dup_name, colon + 1);
+	free(dup_name);
+	return id >= 0;
+}

tools/perf/util/tp_pmu.h

@@ -2,11 +2,18 @@
 #ifndef __TP_PMU_H
 #define __TP_PMU_H
 
+#include "pmu.h"
+
 typedef int (*tp_sys_callback)(void *state, const char *sys_name);
 typedef int (*tp_event_callback)(void *state, const char *sys_name, const char *evt_name);
 
 int tp_pmu__id(const char *sys, const char *name);
 int tp_pmu__for_each_tp_event(const char *sys, void *state, tp_event_callback cb);
 int tp_pmu__for_each_tp_sys(void *state, tp_sys_callback cb);
 
+bool perf_pmu__is_tracepoint(const struct perf_pmu *pmu);
+int tp_pmu__for_each_event(struct perf_pmu *pmu, void *state, pmu_event_callback cb);
+size_t tp_pmu__num_events(struct perf_pmu *pmu);
+bool tp_pmu__have_event(struct perf_pmu *pmu, const char *name);
+
 #endif /* __TP_PMU_H */