[03/22] perf record, bpf: Create probe points for BPF programs

diff --git a/tools/perf/util/bpf-loader.c b/tools/perf/util/bpf-loader.c
index ab56073..1a10b6c 100644
--- a/tools/perf/util/bpf-loader.c
+++ b/tools/perf/util/bpf-loader.c
@@ -10,6 +10,8 @@ 
 #include "perf.h"
 #include "debug.h"
 #include "bpf-loader.h"
+#include "probe-event.h"
+#include "probe-finder.h" // for MAX_PROBES
 
 #define DEFINE_PRINT_FN(name, level) \
 static int libbpf_##name(const char *fmt, ...)	\
@@ -27,6 +29,10 @@  DEFINE_PRINT_FN(warning, 0)
 DEFINE_PRINT_FN(info, 0)
 DEFINE_PRINT_FN(debug, 1)
 
+struct bpf_prog_priv {
+	struct perf_probe_event pev;
+};
+
 struct bpf_object *bpf__prepare_load(const char *filename)
 {
 	struct bpf_object *obj;
@@ -52,6 +58,219 @@  void bpf__clear(void)
 {
 	struct bpf_object *obj, *tmp;
 
-	bpf_object__for_each_safe(obj, tmp)
+	bpf_object__for_each_safe(obj, tmp) {
+		bpf__unprobe(obj);
 		bpf_object__close(obj);
+	}
+}
+
+static void
+bpf_prog_priv__clear(struct bpf_program *prog __maybe_unused,
+		     void *_priv)
+{
+	struct bpf_prog_priv *priv = _priv;
+
+	cleanup_perf_probe_events(&priv->pev, 1);
+	free(priv);
+}
+
+static int
+config_bpf_program(struct bpf_program *prog)
+{
+	struct perf_probe_event *pev = NULL;
+	struct bpf_prog_priv *priv = NULL;
+	const char *config_str;
+	int err;
+
+	config_str = bpf_program__title(prog, false);
+	if (!config_str) {
+		pr_debug("bpf: unable to get title for program\n");
+		return -EINVAL;
+	}
+
+	priv = calloc(sizeof(*priv), 1);
+	if (!priv) {
+		pr_debug("bpf: failed to alloc priv\n");
+		return -ENOMEM;
+	}
+	pev = &priv->pev;
+
+	pr_debug("bpf: config program '%s'\n", config_str);
+	err = parse_perf_probe_command(config_str, pev);
+	if (err < 0) {
+		pr_debug("bpf: '%s' is not a valid config string\n",
+			 config_str);
+		err = -EINVAL;
+		goto errout;
+	}
+
+	if (pev->group && strcmp(pev->group, PERF_BPF_PROBE_GROUP)) {
+		pr_debug("bpf: '%s': group for event is set and not '%s'.\n",
+			 config_str, PERF_BPF_PROBE_GROUP);
+		err = -EINVAL;
+		goto errout;
+	} else if (!pev->group)
+		pev->group = strdup(PERF_BPF_PROBE_GROUP);
+
+	if (!pev->group) {
+		pr_debug("bpf: strdup failed\n");
+		err = -ENOMEM;
+		goto errout;
+	}
+
+	if (!pev->event) {
+		pr_debug("bpf: '%s': event name is missing\n",
+			 config_str);
+		err = -EINVAL;
+		goto errout;
+	}
+	pr_debug("bpf: config '%s' is ok\n", config_str);
+
+	err = bpf_program__set_private(prog, priv, bpf_prog_priv__clear);
+	if (err) {
+		pr_debug("Failed to set priv for program '%s'\n", config_str);
+		goto errout;
+	}
+
+	return 0;
+
+errout:
+	if (pev)
+		clear_perf_probe_event(pev);
+	free(priv);
+	return err;
+}
+
+static int bpf__prepare_probe(void)
+{
+	static int err = 0;
+	static bool initialized = false;
+
+	/*
+	 * Make err static, so if init failed the first, bpf__prepare_probe()
+	 * fails each time without calling init_probe_symbol_maps multiple
+	 * times.
+	 */
+	if (initialized)
+		return err;
+
+	initialized = true;
+	err = init_probe_symbol_maps(false);
+	if (err < 0)
+		pr_debug("Failed to init_probe_symbol_maps\n");
+	probe_conf.max_probes = MAX_PROBES;
+	return err;
+}
+
+int bpf__probe(struct bpf_object *obj)
+{
+	int err = 0;
+	struct bpf_program *prog;
+	struct bpf_prog_priv *priv;
+	struct perf_probe_event *pev;
+
+	err = bpf__prepare_probe();
+	if (err) {
+		pr_debug("bpf__prepare_probe failed\n");
+		return err;
+	}
+
+	bpf_object__for_each_program(prog, obj) {
+		err = config_bpf_program(prog);
+		if (err)
+			goto out;
+
+		err = bpf_program__get_private(prog, (void **)&priv);
+		if (err || !priv)
+			goto out;
+		pev = &priv->pev;
+
+		err = convert_perf_probe_events(pev, 1);
+		if (err < 0) {
+			pr_debug("bpf_probe: failed to convert perf probe events");
+			goto out;
+		}
+
+		err = apply_perf_probe_events(pev, 1);
+		if (err < 0) {
+			pr_debug("bpf_probe: failed to apply perf probe events");
+			goto out;
+		}
+	}
+out:
+	return err < 0 ? err : 0;
+}
+
+#define EVENTS_WRITE_BUFSIZE  4096
+int bpf__unprobe(struct bpf_object *obj)
+{
+	int err, ret = 0;
+	struct bpf_program *prog;
+	struct bpf_prog_priv *priv;
+
+	bpf_object__for_each_program(prog, obj) {
+		int i;
+
+		err = bpf_program__get_private(prog, (void **)&priv);
+		if (err || !priv)
+			continue;
+
+		for (i = 0; i < priv->pev.ntevs; i++) {
+			struct probe_trace_event *tev = &priv->pev.tevs[i];
+			char name_buf[EVENTS_WRITE_BUFSIZE];
+			struct strfilter *delfilter;
+
+			snprintf(name_buf, EVENTS_WRITE_BUFSIZE,
+				 "%s:%s", tev->group, tev->event);
+
+			delfilter = strfilter__new(name_buf, NULL);
+			if (!delfilter) {
+				pr_debug("Failed to create filter for unprobing\n");
+				ret = -ENOMEM;
+				continue;
+			}
+
+			err = del_perf_probe_events(delfilter);
+			strfilter__delete(delfilter);
+			if (err) {
+				pr_debug("Failed to delete %s\n", name_buf);
+				ret = err;
+				continue;
+			}
+		}
+	}
+	return ret;
+}
+
+#define bpf__strerror_head(err, buf, size) \
+	char sbuf[STRERR_BUFSIZE], *emsg;\
+	if (!size)\
+		return 0;\
+	if (err < 0)\
+		err = -err;\
+	emsg = strerror_r(err, sbuf, sizeof(sbuf));\
+	switch (err) {\
+	default:\
+		scnprintf(buf, size, "%s", emsg);\
+		break;
+
+#define bpf__strerror_entry(val, fmt...)\
+	case val: {\
+		scnprintf(buf, size, fmt);\
+		break;\
+	}
+
+#define bpf__strerror_end(buf, size)\
+	}\
+	buf[size - 1] = '\0';
+
+int bpf__strerror_probe(struct bpf_object *obj __maybe_unused,
+			int err, char *buf, size_t size)
+{
+	bpf__strerror_head(err, buf, size);
+	bpf__strerror_entry(EEXIST, "Probe point exist. Try use 'perf probe -d \"*\"'");
+	bpf__strerror_entry(EPERM, "You need to be root, and /proc/sys/kernel/kptr_restrict should be 0\n");
+	bpf__strerror_entry(ENOENT, "You need to check probing points in BPF file\n");
+	bpf__strerror_end(buf, size);
+	return 0;
 }
diff --git a/tools/perf/util/bpf-loader.h b/tools/perf/util/bpf-loader.h
index f402d7c..b819622 100644
--- a/tools/perf/util/bpf-loader.h
+++ b/tools/perf/util/bpf-loader.h
@@ -11,11 +11,18 @@ 
 #include "debug.h"
 
 struct bpf_object;
+#define PERF_BPF_PROBE_GROUP "perf_bpf_probe"
 
 #ifdef HAVE_LIBBPF_SUPPORT
 struct bpf_object *bpf__prepare_load(const char *filename);
 
 void bpf__clear(void);
+
+int bpf__probe(struct bpf_object *obj);
+int bpf__unprobe(struct bpf_object *obj);
+int bpf__strerror_probe(struct bpf_object *obj, int err,
+			char *buf, size_t size);
+
 #else
 static inline struct bpf_object *
 bpf__prepare_load(const char *filename __maybe_unused)
@@ -25,5 +32,28 @@  bpf__prepare_load(const char *filename __maybe_unused)
 }
 
 static inline void bpf__clear(void) { }
+
+static inline int bpf__probe(struct bpf_object *obj __maybe_unused) { return 0;}
+static inline int bpf__unprobe(struct bpf_object *obj __maybe_unused) { return 0;}
+
+static inline int
+__bpf_strerror(char *buf, size_t size)
+{
+	if (!size)
+		return 0;
+	strncpy(buf,
+		"ERROR: eBPF object loading is disabled during compiling.\n",
+		size);
+	buf[size - 1] = '\0';
+	return 0;
+}
+
+static inline int
+bpf__strerror_probe(struct bpf_object *obj __maybe_unused,
+		    int err __maybe_unused,
+		    char *buf, size_t size)
+{
+	return __bpf_strerror(buf, size);
+}
 #endif
 #endif
diff --git a/tools/perf/util/parse-events.c b/tools/perf/util/parse-events.c
index 0d4afba..354da59 100644
--- a/tools/perf/util/parse-events.c
+++ b/tools/perf/util/parse-events.c
@@ -522,6 +522,7 @@  int parse_events_load_bpf_obj(struct parse_events_evlist *data,
 {
 	int err;
 	char errbuf[BUFSIZ];
+	static bool registered_unprobe_atexit = false;
 
 	if (IS_ERR(obj) || !obj) {
 		snprintf(errbuf, sizeof(errbuf),
@@ -530,6 +531,17 @@  int parse_events_load_bpf_obj(struct parse_events_evlist *data,
 		goto errout;
 	}
 
+	err = bpf__probe(obj);
+	if (err) {
+		bpf__strerror_probe(obj, err, errbuf, sizeof(errbuf));
+		goto errout;
+	}
+
+	if (!registered_unprobe_atexit) {
+		atexit(bpf__clear);
+		registered_unprobe_atexit = true;
+	}
+
 	/*
 	 * Temporary add a dummy event here so we can check whether
 	 * basic bpf loader works. Will be removed in following patch.