[PATCH v8 perf,bpf 07/15] perf, bpf: save bpf_prog_info information as headers to perf.data

Song Liu
2019-03-11T19:56:46Z

This patch enables perf-record to save bpf_prog_info information as
headers to perf.data. A new header type HEADER_BPF_PROG_INFO is
introduced for this data.

Signed-off-by: Song Liu <songliubraving@fb.com>
---
tools/perf/util/header.c | 139 ++++++++++++++++++++++++++++++++++++++-
tools/perf/util/header.h | 1 +
2 files changed, 139 insertions(+), 1 deletion(-)

diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c
index 4b88de5e9192..e53ee3111430 100644
--- a/tools/perf/util/header.c
+++ b/tools/perf/util/header.c
@@ -18,6 +18,7 @@
#include <sys/utsname.h>
#include <linux/time64.h>
#include <dirent.h>
+#include <bpf/libbpf.h>

#include "evlist.h"
#include "evsel.h"
@@ -39,6 +40,7 @@
#include "tool.h"
#include "time-utils.h"
#include "units.h"
+#include "bpf-event.h"

#include "sane_ctype.h"

@@ -1074,6 +1076,48 @@ static int write_clockid(struct feat_fd *ff,
sizeof(ff->ph->env.clockid_res_ns));
}

+static int write_bpf_prog_info(struct feat_fd *ff,
+ struct perf_evlist *evlist __maybe_unused)
+{
+ struct perf_env *env = &ff->ph->env;
+ struct rb_root *root;
+ struct rb_node *next;
+ int ret;
+
+ down_read(&env->bpf_progs.lock);
+
+ ret = do_write(ff, &env->bpf_progs.infos_cnt,
+ sizeof(env->bpf_progs.infos_cnt));
+ if (ret < 0)
+ goto out;
+
+ root = &env->bpf_progs.infos;
+ next = rb_first(root);
+ while (next) {
+ struct bpf_prog_info_node *node;
+ size_t len;
+
+ node = rb_entry(next, struct bpf_prog_info_node, rb_node);
+ next = rb_next(&node->rb_node);
+ len = sizeof(struct bpf_prog_info_linear) +
+ node->info_linear->data_len;
+
+ /* before writing to file, translate address to offset */
+ bpf_program__bpil_addr_to_offs(node->info_linear);
+ ret = do_write(ff, node->info_linear, len);
+ /*
+ * translate back to address even when do_write() fails,
+ * so that this function never changes the data.
+ */
+ bpf_program__bpil_offs_to_addr(node->info_linear);
+ if (ret < 0)
+ goto out;
+ }
+out:
+ up_read(&env->bpf_progs.lock);
+ return ret;
+}
+
static int cpu_cache_level__sort(const void *a, const void *b)
{
struct cpu_cache_level *cache_a = (struct cpu_cache_level *)a;
@@ -1554,6 +1598,29 @@ static void print_clockid(struct feat_fd *ff, FILE *fp)
ff->ph->env.clockid_res_ns * 1000);
}

+static void print_bpf_prog_info(struct feat_fd *ff, FILE *fp)
+{
+ struct perf_env *env = &ff->ph->env;
+ struct rb_root *root;
+ struct rb_node *next;
+
+ down_read(&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);
+ fprintf(fp, "# bpf_prog_info of id %u\n",
+ node->info_linear->info.id);
+ }
+
+ up_read(&env->bpf_progs.lock);
+}
+
static void free_event_desc(struct perf_evsel *events)
{
struct perf_evsel *evsel;
@@ -2586,6 +2653,75 @@ static int process_clockid(struct feat_fd *ff,
return 0;
}

+static int process_bpf_prog_info(struct feat_fd *ff,
+ void *data __maybe_unused)
+{
+ struct bpf_prog_info_linear *info_linear;
+ struct bpf_prog_info_node *info_node;
+ struct perf_env *env = &ff->ph->env;
+ u32 count, i;
+ int err = -1;
+
+ if (ff->ph->needs_swap) {
+ pr_warning("interpreting bpf_prog_info from systems with endianity is not yet supported\n");
+ return 0;
+ }
+
+ if (do_read_u32(ff, &count))
+ return -1;
+
+ down_write(&env->bpf_progs.lock);
+
+ for (i = 0; i < count; ++i) {
+ u32 info_len, data_len;
+
+ info_linear = NULL;
+ info_node = NULL;
+ if (do_read_u32(ff, &info_len))
+ goto out;
+ if (do_read_u32(ff, &data_len))
+ goto out;
+
+ if (info_len > sizeof(struct bpf_prog_info)) {
+ pr_warning("detected invalid bpf_prog_info\n");
+ goto out;
+ }
+
+ info_linear = malloc(sizeof(struct bpf_prog_info_linear) +
+ data_len);
+ if (!info_linear)
+ goto out;
+ info_linear->info_len = sizeof(struct bpf_prog_info);
+ info_linear->data_len = data_len;
+ if (do_read_u64(ff, (u64 *)(&info_linear->arrays)))
+ goto out;
+ if (__do_read(ff, &info_linear->info, info_len))
+ goto out;
+ if (info_len < sizeof(struct bpf_prog_info))
+ memset(((void *)(&info_linear->info)) + info_len, 0,
+ sizeof(struct bpf_prog_info) - info_len);
+
+ if (__do_read(ff, info_linear->data, data_len))
+ goto out;
+
+ info_node = malloc(sizeof(struct bpf_prog_info_node));
+ if (!info_node)
+ goto out;
+
+ /* after reading from file, translate offset to address */
+ bpf_program__bpil_offs_to_addr(info_linear);
+ info_node->info_linear = info_linear;
+ perf_env__insert_bpf_prog_info(env, info_node);
+ }
+
+ return 0;
+out:
+ free(info_linear);
+ free(info_node);
+ up_write(&env->bpf_progs.lock);
+ return err;
+}
+
struct feature_ops {
int (*write)(struct feat_fd *ff, struct perf_evlist *evlist);
void (*print)(struct feat_fd *ff, FILE *fp);
@@ -2645,7 +2781,8 @@ static const struct feature_ops feat_ops[HEADER_LAST_FEATURE] = {
FEAT_OPN(CACHE, cache, true),
FEAT_OPR(SAMPLE_TIME, sample_time, false),
FEAT_OPR(MEM_TOPOLOGY, mem_topology, true),
- FEAT_OPR(CLOCKID, clockid, false)
+ FEAT_OPR(CLOCKID, clockid, false),
+ FEAT_OPR(BPF_PROG_INFO, bpf_prog_info, false)
};

struct header_print_data {
diff --git a/tools/perf/util/header.h b/tools/perf/util/header.h
index 0d553ddca0a3..0785c91b4c3a 100644
--- a/tools/perf/util/header.h
+++ b/tools/perf/util/header.h
@@ -39,6 +39,7 @@ enum {
HEADER_SAMPLE_TIME,
HEADER_MEM_TOPOLOGY,
HEADER_CLOCKID,
+ HEADER_BPF_PROG_INFO,
HEADER_LAST_FEATURE,
HEADER_FEAT_BITS = 256,
};
--
2.17.1