perf bpf: Save bpf_prog_info in a rbtree in perf_env

bpf_prog_info contains information necessary to annotate bpf programs.

This patch saves bpf_prog_info for bpf programs loaded in the system.

Some big picture of the next few patches:

To fully annotate BPF programs with source code mapping, 4 different
informations are needed:

    1) PERF_RECORD_KSYMBOL
    2) PERF_RECORD_BPF_EVENT
    3) bpf_prog_info
    4) btf

Before this set, 1) and 2) in the list are already saved to perf.data
file. For BPF programs that are already loaded before perf run, 1) and 2)
are synthesized by perf_event__synthesize_bpf_events(). For short living
BPF programs, 1) and 2) are generated by kernel.

This set handles 3) and 4) from the list. Again, it is necessary to handle
existing BPF program and short living program separately.

This patch handles 3) for exising BPF programs while synthesizing 1) and
2) in perf_event__synthesize_bpf_events(). These data are stored in
perf_env. The next patch saves these data from perf_env to perf.data as
headers.

Similarly, the two patches after the next saves 4) of existing BPF
programs to perf_env and perf.data.

Another patch later will handle 3) and 4) for short living BPF programs
by monitoring 1) and 2) in a dedicate thread.

Signed-off-by: Song Liu <songliubraving@fb.com>
Reviewed-by: Jiri Olsa <jolsa@kernel.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stanislav Fomichev <sdf@google.com>
Cc: kernel-team@fb.com
Link: http://lkml.kernel.org/r/20190312053051.2690567-7-songliubraving@fb.com
[ set env->bpf_progs.infos_cnt to zero in perf_env__purge_bpf() as noted by jolsa ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 88 insertions, 0 deletions

diff --git a/tools/perf/util/env.c b/tools/perf/util/env.c
index 4c23779e271a..98cd36f0e317 100644
--- a/tools/perf/util/env.c
+++ b/tools/perf/util/env.c
@@ -3,15 +3,97 @@
 #include "env.h"
 #include "sane_ctype.h"
 #include "util.h"
+#include "bpf-event.h"
 #include <errno.h>
 #include <sys/utsname.h>
+#include <bpf/libbpf.h>
 
 struct perf_env perf_env;
 
+void perf_env__insert_bpf_prog_info(struct perf_env *env,
+				    struct bpf_prog_info_node *info_node)
+{
+	__u32 prog_id = info_node->info_linear->info.id;
+	struct bpf_prog_info_node *node;
+	struct rb_node *parent = NULL;
+	struct rb_node **p;
+
+	down_write(&env->bpf_progs.lock);
+	p = &env->bpf_progs.infos.rb_node;
+
+	while (*p != NULL) {
+		parent = *p;
+		node = rb_entry(parent, struct bpf_prog_info_node, rb_node);
+		if (prog_id < node->info_linear->info.id) {
+			p = &(*p)->rb_left;
+		} else if (prog_id > node->info_linear->info.id) {
+			p = &(*p)->rb_right;
+		} else {
+			pr_debug("duplicated bpf prog info %u\n", prog_id);
+			goto out;
+		}
+	}
+
+	rb_link_node(&info_node->rb_node, parent, p);
+	rb_insert_color(&info_node->rb_node, &env->bpf_progs.infos);
+	env->bpf_progs.infos_cnt++;
+out:
+	up_write(&env->bpf_progs.lock);
+}
+
+struct bpf_prog_info_node *perf_env__find_bpf_prog_info(struct perf_env *env,
+							__u32 prog_id)
+{
+	struct bpf_prog_info_node *node = NULL;
+	struct rb_node *n;
+
+	down_read(&env->bpf_progs.lock);
+	n = env->bpf_progs.infos.rb_node;
+
+	while (n) {
+		node = rb_entry(n, struct bpf_prog_info_node, rb_node);
+		if (prog_id < node->info_linear->info.id)
+			n = n->rb_left;
+		else if (prog_id > node->info_linear->info.id)
+			n = n->rb_right;
+		else
+			break;
+	}
+
+	up_read(&env->bpf_progs.lock);
+	return node;
+}
+
+/* purge data in bpf_progs.infos tree */
+static void perf_env__purge_bpf(struct perf_env *env)
+{
+	struct rb_root *root;
+	struct rb_node *next;
+
+	down_write(&env->bpf_progs.lock);
+
+	root = &env->bpf_progs.infos;
+	next = rb_first(root);
+
+	while (next) {
+		struct bpf_prog_info_node *node;
+
+		node = rb_entry(next, struct bpf_prog_info_node, rb_node);
+		next = rb_next(&node->rb_node);
+		rb_erase(&node->rb_node, root);
+		free(node);
+	}
+
+	env->bpf_progs.infos_cnt = 0;
+
+	up_write(&env->bpf_progs.lock);
+}
+
 void perf_env__exit(struct perf_env *env)
 {
 	int i;
 
+	perf_env__purge_bpf(env);
 	zfree(&env->hostname);
 	zfree(&env->os_release);
 	zfree(&env->version);
@@ -38,6 +120,12 @@ void perf_env__exit(struct perf_env *env)
 	zfree(&env->memory_nodes);
 }
 
+void perf_env__init(struct perf_env *env)
+{
+	env->bpf_progs.infos = RB_ROOT;
+	init_rwsem(&env->bpf_progs.lock);
+}
+
 int perf_env__set_cmdline(struct perf_env *env, int argc, const char *argv[])
 {
 	int i;