bpf__config_obj() is introduced as a core API to config BPF object
after loading. One configuration option of maps is introduced. After
this patch BPF object can accept configuration like:
maps.my_map.value=1234
This patch is more complex than the work it really does because the
consideration of extension. In designing of BPF map configuration,
following things should be considered:
1. Array indics selection: perf should allow user setting different
value to different slots in an array, with syntax like:
maps.my_map.value[0,3-6]=1234;
2. Type of value: integer is not the only valid value type. Perf
event can also be put into a map after commit 35578d7984003097af2b1e3
(bpf: Implement function bpf_perf_event_read() that get the selected
hardware PMU conuter);
3. For hash table, it is possible to use string or other as key;
4. It is possible that map configuration is unable to be setup
during parsing. Perf event is an example.
Therefore, this patch does tie following thing for extension:
1. Instead of update map element during parsing, this patch stores
map config options in 'struct bpf_map_priv'. Following patches
would apply those configs at proper time;
2. Make 'struct bpf_map_priv' extensible so following patches can
add new key and value operations;
3. Use bpf_config_map_funcs array to support more maps configuration.
Signed-off-by: Wang Nan <[email protected]>
Signed-off-by: He Kuang <[email protected]>
Cc: Arnaldo Carvalho de Melo <[email protected]>
Cc: Alexei Starovoitov <[email protected]>
Cc: Brendan Gregg <[email protected]>
Cc: Daniel Borkmann <[email protected]>
Cc: David Ahern <[email protected]>
Cc: He Kuang <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Kaixu Xia <[email protected]>
Cc: Masami Hiramatsu <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Paul Mackerras <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Zefan Li <[email protected]>
Cc: [email protected]
Link: http://lkml.kernel.org/n/[email protected]
---
tools/perf/util/bpf-loader.c | 180 +++++++++++++++++++++++++++++++++++++++++++
tools/perf/util/bpf-loader.h | 27 +++++++
2 files changed, 207 insertions(+)
diff --git a/tools/perf/util/bpf-loader.c b/tools/perf/util/bpf-loader.c
index 73ff9a9..a5a1c36 100644
--- a/tools/perf/util/bpf-loader.c
+++ b/tools/perf/util/bpf-loader.c
@@ -10,11 +10,13 @@
#include <linux/err.h>
#include "perf.h"
#include "debug.h"
+#include "util.h"
#include "bpf-loader.h"
#include "bpf-prologue.h"
#include "llvm-utils.h"
#include "probe-event.h"
#include "probe-finder.h" // for MAX_PROBES
+#include "parse-events.h"
#include "llvm-utils.h"
#define DEFINE_PRINT_FN(name, level) \
@@ -633,6 +635,170 @@ int bpf__foreach_tev(struct bpf_object *obj,
return 0;
}
+enum bpf_map_priv_key_type {
+ BPF_MAP_PRIV_KEY_ALL,
+};
+
+enum bpf_map_priv_value_type {
+ BPF_MAP_PRIV_VAL_VALUE,
+};
+
+struct bpf_map_priv {
+ struct {
+ enum bpf_map_priv_key_type type;
+ } key;
+
+ struct {
+ enum bpf_map_priv_value_type type;
+ union {
+ u64 val;
+ };
+ } value;
+};
+
+static void
+bpf_map_priv__clear(struct bpf_map *map __maybe_unused,
+ void *_priv)
+{
+ struct bpf_map_priv *priv = _priv;
+
+ free(priv);
+}
+
+static int
+bpf__config_obj_map_array_value(struct bpf_map *map,
+ struct parse_events_term *term)
+{
+ struct bpf_map_priv *priv;
+ struct bpf_map_def def;
+ const char *map_name;
+ int err;
+
+ map_name = bpf_map__get_name(map);
+
+ err = bpf_map__get_def(map, &def);
+ if (err) {
+ pr_debug("Unable to get map definition from '%s'\n",
+ map_name);
+ return -EINVAL;
+ }
+
+ if (def.type != BPF_MAP_TYPE_ARRAY) {
+ pr_debug("Map %s type is not BPF_MAP_TYPE_ARRAY\n",
+ map_name);
+ return -EBADF;
+ }
+ if (def.key_size < sizeof(unsigned int)) {
+ pr_debug("Map %s has incorrect key size\n", map_name);
+ return -EINVAL;
+ }
+ switch (def.value_size) {
+ case 1:
+ case 2:
+ case 4:
+ case 8:
+ break;
+ default:
+ pr_debug("Map %s has incorrect value size\n", map_name);
+ return -EINVAL;
+ }
+
+ priv = zalloc(sizeof(*priv));
+ if (!priv) {
+ pr_debug("No enough memory to alloc map private\n");
+ return -ENOMEM;
+ }
+
+ priv->key.type = BPF_MAP_PRIV_KEY_ALL;
+ priv->value.type = BPF_MAP_PRIV_VAL_VALUE;
+ priv->value.val = term->val.num;
+ return bpf_map__set_private(map, priv, bpf_map_priv__clear);
+}
+
+static int
+bpf__config_obj_map_value(struct bpf_map *map,
+ struct parse_events_term *term,
+ struct perf_evlist *evlist __maybe_unused)
+{
+ if (term->type_val == PARSE_EVENTS__TERM_TYPE_NUM)
+ return bpf__config_obj_map_array_value(map, term);
+
+ pr_debug("ERROR: wrong value type\n");
+ return -EINVAL;
+}
+
+struct bpf_config_map_func {
+ const char *config_opt;
+ int (*config_func)(struct bpf_map *, struct parse_events_term *,
+ struct perf_evlist *);
+};
+
+struct bpf_config_map_func bpf_config_map_funcs[] = {
+ {"value", bpf__config_obj_map_value},
+};
+
+static int
+bpf__config_obj_map(struct bpf_object *obj,
+ struct parse_events_term *term,
+ struct perf_evlist *evlist)
+{
+ /* key is "maps.<mapname>.<config opt>" */
+ char *map_name = strdup(term->config + sizeof("maps.") - 1);
+ struct bpf_map *map;
+ int err = -ENOENT;
+ char *map_opt;
+ size_t i;
+
+ if (!map_name)
+ return -ENOMEM;
+
+ map_opt = strchr(map_name, '.');
+ if (!map_opt) {
+ pr_debug("ERROR: Invalid map config: %s\n", map_name);
+ goto out;
+ }
+
+ *map_opt++ = '\0';
+ if (*map_opt == '\0') {
+ pr_debug("ERROR: Invalid map option: %s\n", term->config);
+ goto out;
+ }
+
+ map = bpf_object__get_map_by_name(obj, map_name);
+ if (!map) {
+ pr_debug("ERROR: Map %s doesn't exist\n", map_name);
+ goto out;
+ }
+
+ for (i = 0; i < ARRAY_SIZE(bpf_config_map_funcs); i++) {
+ struct bpf_config_map_func *func = &bpf_config_map_funcs[i];
+
+ if (strcmp(map_opt, func->config_opt) == 0) {
+ err = func->config_func(map, term, evlist);
+ goto out;
+ }
+ }
+
+ pr_debug("ERROR: invalid config option '%s' for maps\n",
+ map_opt);
+ err = -ENOENT;
+out:
+ free(map_name);
+ return err;
+}
+
+int bpf__config_obj(struct bpf_object *obj,
+ struct parse_events_term *term,
+ struct perf_evlist *evlist)
+{
+ if (!obj || !term || !term->config)
+ return -ENODEV;
+
+ if (!prefixcmp(term->config, "maps."))
+ return bpf__config_obj_map(obj, term, evlist);
+ return -ENODEV;
+}
+
#define bpf__strerror_head(err, buf, size) \
char sbuf[STRERR_BUFSIZE], *emsg;\
if (!size)\
@@ -675,3 +841,17 @@ int bpf__strerror_load(struct bpf_object *obj
__maybe_unused,
bpf__strerror_end(buf, size);
return 0;
}
+
+int bpf__strerror_config_obj(struct bpf_object *obj __maybe_unused,
+ struct parse_events_term *term,
+ struct perf_evlist *evlist __maybe_unused,
+ int err, char *buf, size_t size)
+{
+ bpf__strerror_head(err, buf, size);
+ bpf__strerror_entry(ENODEV, "Invalid config option: '%s'", term->config)
+ bpf__strerror_entry(ENOENT, "Config target in '%s' is invalid",
term->config)
+ bpf__strerror_entry(EBADF, "Map type mismatch in '%s'", term->config)
+ bpf__strerror_entry(EINVAL, "Invalid config value")
+ bpf__strerror_end(buf, size);
+ return 0;
+}
diff --git a/tools/perf/util/bpf-loader.h b/tools/perf/util/bpf-loader.h
index d8f1945..dfec9b8 100644
--- a/tools/perf/util/bpf-loader.h
+++ b/tools/perf/util/bpf-loader.h
@@ -9,9 +9,11 @@
#include <linux/err.h>
#include <string.h>
#include "probe-event.h"
+#include "evlist.h"
#include "debug.h"
struct bpf_object;
+struct parse_events_term;
#define PERF_BPF_PROBE_GROUP "perf_bpf_probe"
typedef int (*bpf_prog_iter_callback_t)(struct probe_trace_event *tev,
@@ -34,6 +36,13 @@ int bpf__strerror_load(struct bpf_object *obj, int err,
char *buf, size_t size);
int bpf__foreach_tev(struct bpf_object *obj,
bpf_prog_iter_callback_t func, void *arg);
+
+int bpf__config_obj(struct bpf_object *obj, struct parse_events_term *term,
+ struct perf_evlist *evlist);
+int bpf__strerror_config_obj(struct bpf_object *obj,
+ struct parse_events_term *term,
+ struct perf_evlist *evlist,
+ int err, char *buf, size_t size);
#else
static inline struct bpf_object *
bpf__prepare_load(const char *filename __maybe_unused,
@@ -65,6 +74,14 @@ bpf__foreach_tev(struct bpf_object *obj __maybe_unused,
}
static inline int
+bpf__config_obj(struct bpf_object *obj __maybe_unused,
+ struct parse_events_term *term __maybe_unused,
+ struct perf_evlist *evlist __maybe_unused)
+{
+ return 0;
+}
+
+static inline int
__bpf_strerror(char *buf, size_t size)
{
if (!size)
@@ -90,5 +107,15 @@ static inline int bpf__strerror_load(struct bpf_object *obj
__maybe_unused,
{
return __bpf_strerror(buf, size);
}
+
+static inline int
+bpf__strerror_config_obj(struct bpf_object *obj __maybe_unused,
+ struct parse_events_term *term __maybe_unused,
+ struct perf_evlist *evlist __maybe_unused,
+ int err __maybe_unused,
+ char *buf, size_t size)
+{
+ return __bpf_strerror(buf, size);
+}
#endif
#endif
--
1.8.3.4
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