perf bpf: Save BTF in a rbtree in perf_env

BTF contains information necessary to annotate BPF programs. This patch
saves BTF for BPF programs loaded in the system.

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/20190312053051.2690567-9-songliubraving@fb.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/perf/util/bpf-event.c b/tools/perf/util/bpf-event.c
index 37ee4e2..a4fc52b 100644 (file)
--- a/tools/perf/util/bpf-event.c
+++ b/tools/perf/util/bpf-event.c
@@ -34,6 +34,28 @@ int machine__process_bpf_event(struct machine *machine __maybe_unused,
        return 0;
 }
 
+static int perf_env__fetch_btf(struct perf_env *env,
+                              u32 btf_id,
+                              struct btf *btf)
+{
+       struct btf_node *node;
+       u32 data_size;
+       const void *data;
+
+       data = btf__get_raw_data(btf, &data_size);
+
+       node = malloc(data_size + sizeof(struct btf_node));
+       if (!node)
+               return -1;
+
+       node->id = btf_id;
+       node->data_size = data_size;
+       memcpy(node->data, data, data_size);
+
+       perf_env__insert_btf(env, node);
+       return 0;
+}
+
 /*
  * Synthesize PERF_RECORD_KSYMBOL and PERF_RECORD_BPF_EVENT for one bpf
  * program. One PERF_RECORD_BPF_EVENT is generated for the program. And
@@ -113,6 +135,7 @@ static int perf_event__synthesize_one_bpf_prog(struct perf_session *session,
                        goto out;
                }
                has_btf = true;
+               perf_env__fetch_btf(env, info->btf_id, btf);
        }
 
        /* Synthesize PERF_RECORD_KSYMBOL */

diff --git a/tools/perf/util/bpf-event.h b/tools/perf/util/bpf-event.h
index fad932f..b9ec394 100644 (file)
--- a/tools/perf/util/bpf-event.h
+++ b/tools/perf/util/bpf-event.h
@@ -16,6 +16,13 @@ struct bpf_prog_info_node {
        struct rb_node                  rb_node;
 };
 
+struct btf_node {
+       struct rb_node  rb_node;
+       u32             id;
+       u32             data_size;
+       char            data[];
+};
+
 #ifdef HAVE_LIBBPF_SUPPORT
 int machine__process_bpf_event(struct machine *machine, union perf_event *event,
                               struct perf_sample *sample);

diff --git a/tools/perf/util/env.c b/tools/perf/util/env.c
index 98cd36f..c6351b5 100644 (file)
--- a/tools/perf/util/env.c
+++ b/tools/perf/util/env.c
@@ -64,6 +64,58 @@ struct bpf_prog_info_node *perf_env__find_bpf_prog_info(struct perf_env *env,
        return node;
 }
 
+void perf_env__insert_btf(struct perf_env *env, struct btf_node *btf_node)
+{
+       struct rb_node *parent = NULL;
+       __u32 btf_id = btf_node->id;
+       struct btf_node *node;
+       struct rb_node **p;
+
+       down_write(&env->bpf_progs.lock);
+       p = &env->bpf_progs.btfs.rb_node;
+
+       while (*p != NULL) {
+               parent = *p;
+               node = rb_entry(parent, struct btf_node, rb_node);
+               if (btf_id < node->id) {
+                       p = &(*p)->rb_left;
+               } else if (btf_id > node->id) {
+                       p = &(*p)->rb_right;
+               } else {
+                       pr_debug("duplicated btf %u\n", btf_id);
+                       goto out;
+               }
+       }
+
+       rb_link_node(&btf_node->rb_node, parent, p);
+       rb_insert_color(&btf_node->rb_node, &env->bpf_progs.btfs);
+       env->bpf_progs.btfs_cnt++;
+out:
+       up_write(&env->bpf_progs.lock);
+}
+
+struct btf_node *perf_env__find_btf(struct perf_env *env, __u32 btf_id)
+{
+       struct btf_node *node = NULL;
+       struct rb_node *n;
+
+       down_read(&env->bpf_progs.lock);
+       n = env->bpf_progs.btfs.rb_node;
+
+       while (n) {
+               node = rb_entry(n, struct btf_node, rb_node);
+               if (btf_id < node->id)
+                       n = n->rb_left;
+               else if (btf_id > node->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)
 {
@@ -86,6 +138,20 @@ static void perf_env__purge_bpf(struct perf_env *env)
 
        env->bpf_progs.infos_cnt = 0;
 
+       root = &env->bpf_progs.btfs;
+       next = rb_first(root);
+
+       while (next) {
+               struct btf_node *node;
+
+               node = rb_entry(next, struct btf_node, rb_node);
+               next = rb_next(&node->rb_node);
+               rb_erase(&node->rb_node, root);
+               free(node);
+       }
+
+       env->bpf_progs.btfs_cnt = 0;
+
        up_write(&env->bpf_progs.lock);
 }
 
@@ -123,6 +189,7 @@ void perf_env__exit(struct perf_env *env)
 void perf_env__init(struct perf_env *env)
 {
        env->bpf_progs.infos = RB_ROOT;
+       env->bpf_progs.btfs = RB_ROOT;
        init_rwsem(&env->bpf_progs.lock);
 }
 

diff --git a/tools/perf/util/env.h b/tools/perf/util/env.h
index 24b11c5..4f8e2b4 100644 (file)
--- a/tools/perf/util/env.h
+++ b/tools/perf/util/env.h
@@ -75,10 +75,13 @@ struct perf_env {
                struct rw_semaphore     lock;
                struct rb_root          infos;
                u32                     infos_cnt;
+               struct rb_root          btfs;
+               u32                     btfs_cnt;
        } bpf_progs;
 };
 
 struct bpf_prog_info_node;
+struct btf_node;
 
 extern struct perf_env perf_env;
 
@@ -99,4 +102,6 @@ void perf_env__insert_bpf_prog_info(struct perf_env *env,
                                    struct bpf_prog_info_node *info_node);
 struct bpf_prog_info_node *perf_env__find_bpf_prog_info(struct perf_env *env,
                                                        __u32 prog_id);
+void perf_env__insert_btf(struct perf_env *env, struct btf_node *btf_node);
+struct btf_node *perf_env__find_btf(struct perf_env *env, __u32 btf_id);
 #endif /* __PERF_ENV_H */