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-rw-r--r--tools/perf/util/bpf-loader.c433
1 files changed, 425 insertions, 8 deletions
diff --git a/tools/perf/util/bpf-loader.c b/tools/perf/util/bpf-loader.c
index 4c50411371db..540a7efa657e 100644
--- a/tools/perf/util/bpf-loader.c
+++ b/tools/perf/util/bpf-loader.c
@@ -5,11 +5,15 @@
* Copyright (C) 2015 Huawei Inc.
*/
+#include <linux/bpf.h>
#include <bpf/libbpf.h>
#include <linux/err.h>
+#include <linux/string.h>
#include "perf.h"
#include "debug.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 "llvm-utils.h"
@@ -32,6 +36,10 @@ DEFINE_PRINT_FN(debug, 1)
struct bpf_prog_priv {
struct perf_probe_event pev;
+ bool need_prologue;
+ struct bpf_insn *insns_buf;
+ int nr_types;
+ int *type_mapping;
};
static bool libbpf_initialized;
@@ -106,10 +114,178 @@ bpf_prog_priv__clear(struct bpf_program *prog __maybe_unused,
struct bpf_prog_priv *priv = _priv;
cleanup_perf_probe_events(&priv->pev, 1);
+ zfree(&priv->insns_buf);
+ zfree(&priv->type_mapping);
free(priv);
}
static int
+prog_config__exec(const char *value, struct perf_probe_event *pev)
+{
+ pev->uprobes = true;
+ pev->target = strdup(value);
+ if (!pev->target)
+ return -ENOMEM;
+ return 0;
+}
+
+static int
+prog_config__module(const char *value, struct perf_probe_event *pev)
+{
+ pev->uprobes = false;
+ pev->target = strdup(value);
+ if (!pev->target)
+ return -ENOMEM;
+ return 0;
+}
+
+static int
+prog_config__bool(const char *value, bool *pbool, bool invert)
+{
+ int err;
+ bool bool_value;
+
+ if (!pbool)
+ return -EINVAL;
+
+ err = strtobool(value, &bool_value);
+ if (err)
+ return err;
+
+ *pbool = invert ? !bool_value : bool_value;
+ return 0;
+}
+
+static int
+prog_config__inlines(const char *value,
+ struct perf_probe_event *pev __maybe_unused)
+{
+ return prog_config__bool(value, &probe_conf.no_inlines, true);
+}
+
+static int
+prog_config__force(const char *value,
+ struct perf_probe_event *pev __maybe_unused)
+{
+ return prog_config__bool(value, &probe_conf.force_add, false);
+}
+
+static struct {
+ const char *key;
+ const char *usage;
+ const char *desc;
+ int (*func)(const char *, struct perf_probe_event *);
+} bpf_prog_config_terms[] = {
+ {
+ .key = "exec",
+ .usage = "exec=<full path of file>",
+ .desc = "Set uprobe target",
+ .func = prog_config__exec,
+ },
+ {
+ .key = "module",
+ .usage = "module=<module name> ",
+ .desc = "Set kprobe module",
+ .func = prog_config__module,
+ },
+ {
+ .key = "inlines",
+ .usage = "inlines=[yes|no] ",
+ .desc = "Probe at inline symbol",
+ .func = prog_config__inlines,
+ },
+ {
+ .key = "force",
+ .usage = "force=[yes|no] ",
+ .desc = "Forcibly add events with existing name",
+ .func = prog_config__force,
+ },
+};
+
+static int
+do_prog_config(const char *key, const char *value,
+ struct perf_probe_event *pev)
+{
+ unsigned int i;
+
+ pr_debug("config bpf program: %s=%s\n", key, value);
+ for (i = 0; i < ARRAY_SIZE(bpf_prog_config_terms); i++)
+ if (strcmp(key, bpf_prog_config_terms[i].key) == 0)
+ return bpf_prog_config_terms[i].func(value, pev);
+
+ pr_debug("BPF: ERROR: invalid program config option: %s=%s\n",
+ key, value);
+
+ pr_debug("\nHint: Valid options are:\n");
+ for (i = 0; i < ARRAY_SIZE(bpf_prog_config_terms); i++)
+ pr_debug("\t%s:\t%s\n", bpf_prog_config_terms[i].usage,
+ bpf_prog_config_terms[i].desc);
+ pr_debug("\n");
+
+ return -BPF_LOADER_ERRNO__PROGCONF_TERM;
+}
+
+static const char *
+parse_prog_config_kvpair(const char *config_str, struct perf_probe_event *pev)
+{
+ char *text = strdup(config_str);
+ char *sep, *line;
+ const char *main_str = NULL;
+ int err = 0;
+
+ if (!text) {
+ pr_debug("No enough memory: dup config_str failed\n");
+ return ERR_PTR(-ENOMEM);
+ }
+
+ line = text;
+ while ((sep = strchr(line, ';'))) {
+ char *equ;
+
+ *sep = '\0';
+ equ = strchr(line, '=');
+ if (!equ) {
+ pr_warning("WARNING: invalid config in BPF object: %s\n",
+ line);
+ pr_warning("\tShould be 'key=value'.\n");
+ goto nextline;
+ }
+ *equ = '\0';
+
+ err = do_prog_config(line, equ + 1, pev);
+ if (err)
+ break;
+nextline:
+ line = sep + 1;
+ }
+
+ if (!err)
+ main_str = config_str + (line - text);
+ free(text);
+
+ return err ? ERR_PTR(err) : main_str;
+}
+
+static int
+parse_prog_config(const char *config_str, struct perf_probe_event *pev)
+{
+ int err;
+ const char *main_str = parse_prog_config_kvpair(config_str, pev);
+
+ if (IS_ERR(main_str))
+ return PTR_ERR(main_str);
+
+ err = parse_perf_probe_command(main_str, pev);
+ if (err < 0) {
+ pr_debug("bpf: '%s' is not a valid config string\n",
+ config_str);
+ /* parse failed, don't need clear pev. */
+ return -BPF_LOADER_ERRNO__CONFIG;
+ }
+ return 0;
+}
+
+static int
config_bpf_program(struct bpf_program *prog)
{
struct perf_probe_event *pev = NULL;
@@ -117,6 +293,10 @@ config_bpf_program(struct bpf_program *prog)
const char *config_str;
int err;
+ /* Initialize per-program probing setting */
+ probe_conf.no_inlines = false;
+ probe_conf.force_add = false;
+
config_str = bpf_program__title(prog, false);
if (IS_ERR(config_str)) {
pr_debug("bpf: unable to get title for program\n");
@@ -131,13 +311,9 @@ config_bpf_program(struct bpf_program *prog)
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 = -BPF_LOADER_ERRNO__CONFIG;
+ err = parse_prog_config(config_str, pev);
+ if (err)
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",
@@ -197,6 +373,220 @@ static int bpf__prepare_probe(void)
return err;
}
+static int
+preproc_gen_prologue(struct bpf_program *prog, int n,
+ struct bpf_insn *orig_insns, int orig_insns_cnt,
+ struct bpf_prog_prep_result *res)
+{
+ struct probe_trace_event *tev;
+ struct perf_probe_event *pev;
+ struct bpf_prog_priv *priv;
+ struct bpf_insn *buf;
+ size_t prologue_cnt = 0;
+ int i, err;
+
+ err = bpf_program__get_private(prog, (void **)&priv);
+ if (err || !priv)
+ goto errout;
+
+ pev = &priv->pev;
+
+ if (n < 0 || n >= priv->nr_types)
+ goto errout;
+
+ /* Find a tev belongs to that type */
+ for (i = 0; i < pev->ntevs; i++) {
+ if (priv->type_mapping[i] == n)
+ break;
+ }
+
+ if (i >= pev->ntevs) {
+ pr_debug("Internal error: prologue type %d not found\n", n);
+ return -BPF_LOADER_ERRNO__PROLOGUE;
+ }
+
+ tev = &pev->tevs[i];
+
+ buf = priv->insns_buf;
+ err = bpf__gen_prologue(tev->args, tev->nargs,
+ buf, &prologue_cnt,
+ BPF_MAXINSNS - orig_insns_cnt);
+ if (err) {
+ const char *title;
+
+ title = bpf_program__title(prog, false);
+ if (!title)
+ title = "[unknown]";
+
+ pr_debug("Failed to generate prologue for program %s\n",
+ title);
+ return err;
+ }
+
+ memcpy(&buf[prologue_cnt], orig_insns,
+ sizeof(struct bpf_insn) * orig_insns_cnt);
+
+ res->new_insn_ptr = buf;
+ res->new_insn_cnt = prologue_cnt + orig_insns_cnt;
+ res->pfd = NULL;
+ return 0;
+
+errout:
+ pr_debug("Internal error in preproc_gen_prologue\n");
+ return -BPF_LOADER_ERRNO__PROLOGUE;
+}
+
+/*
+ * compare_tev_args is reflexive, transitive and antisymmetric.
+ * I can proof it but this margin is too narrow to contain.
+ */
+static int compare_tev_args(const void *ptev1, const void *ptev2)
+{
+ int i, ret;
+ const struct probe_trace_event *tev1 =
+ *(const struct probe_trace_event **)ptev1;
+ const struct probe_trace_event *tev2 =
+ *(const struct probe_trace_event **)ptev2;
+
+ ret = tev2->nargs - tev1->nargs;
+ if (ret)
+ return ret;
+
+ for (i = 0; i < tev1->nargs; i++) {
+ struct probe_trace_arg *arg1, *arg2;
+ struct probe_trace_arg_ref *ref1, *ref2;
+
+ arg1 = &tev1->args[i];
+ arg2 = &tev2->args[i];
+
+ ret = strcmp(arg1->value, arg2->value);
+ if (ret)
+ return ret;
+
+ ref1 = arg1->ref;
+ ref2 = arg2->ref;
+
+ while (ref1 && ref2) {
+ ret = ref2->offset - ref1->offset;
+ if (ret)
+ return ret;
+
+ ref1 = ref1->next;
+ ref2 = ref2->next;
+ }
+
+ if (ref1 || ref2)
+ return ref2 ? 1 : -1;
+ }
+
+ return 0;
+}
+
+/*
+ * Assign a type number to each tevs in a pev.
+ * mapping is an array with same slots as tevs in that pev.
+ * nr_types will be set to number of types.
+ */
+static int map_prologue(struct perf_probe_event *pev, int *mapping,
+ int *nr_types)
+{
+ int i, type = 0;
+ struct probe_trace_event **ptevs;
+
+ size_t array_sz = sizeof(*ptevs) * pev->ntevs;
+
+ ptevs = malloc(array_sz);
+ if (!ptevs) {
+ pr_debug("No ehough memory: alloc ptevs failed\n");
+ return -ENOMEM;
+ }
+
+ pr_debug("In map_prologue, ntevs=%d\n", pev->ntevs);
+ for (i = 0; i < pev->ntevs; i++)
+ ptevs[i] = &pev->tevs[i];
+
+ qsort(ptevs, pev->ntevs, sizeof(*ptevs),
+ compare_tev_args);
+
+ for (i = 0; i < pev->ntevs; i++) {
+ int n;
+
+ n = ptevs[i] - pev->tevs;
+ if (i == 0) {
+ mapping[n] = type;
+ pr_debug("mapping[%d]=%d\n", n, type);
+ continue;
+ }
+
+ if (compare_tev_args(ptevs + i, ptevs + i - 1) == 0)
+ mapping[n] = type;
+ else
+ mapping[n] = ++type;
+
+ pr_debug("mapping[%d]=%d\n", n, mapping[n]);
+ }
+ free(ptevs);
+ *nr_types = type + 1;
+
+ return 0;
+}
+
+static int hook_load_preprocessor(struct bpf_program *prog)
+{
+ struct perf_probe_event *pev;
+ struct bpf_prog_priv *priv;
+ bool need_prologue = false;
+ int err, i;
+
+ err = bpf_program__get_private(prog, (void **)&priv);
+ if (err || !priv) {
+ pr_debug("Internal error when hook preprocessor\n");
+ return -BPF_LOADER_ERRNO__INTERNAL;
+ }
+
+ pev = &priv->pev;
+ for (i = 0; i < pev->ntevs; i++) {
+ struct probe_trace_event *tev = &pev->tevs[i];
+
+ if (tev->nargs > 0) {
+ need_prologue = true;
+ break;
+ }
+ }
+
+ /*
+ * Since all tevs don't have argument, we don't need generate
+ * prologue.
+ */
+ if (!need_prologue) {
+ priv->need_prologue = false;
+ return 0;
+ }
+
+ priv->need_prologue = true;
+ priv->insns_buf = malloc(sizeof(struct bpf_insn) * BPF_MAXINSNS);
+ if (!priv->insns_buf) {
+ pr_debug("No enough memory: alloc insns_buf failed\n");
+ return -ENOMEM;
+ }
+
+ priv->type_mapping = malloc(sizeof(int) * pev->ntevs);
+ if (!priv->type_mapping) {
+ pr_debug("No enough memory: alloc type_mapping failed\n");
+ return -ENOMEM;
+ }
+ memset(priv->type_mapping, -1,
+ sizeof(int) * pev->ntevs);
+
+ err = map_prologue(pev, priv->type_mapping, &priv->nr_types);
+ if (err)
+ return err;
+
+ err = bpf_program__set_prep(prog, priv->nr_types,
+ preproc_gen_prologue);
+ return err;
+}
+
int bpf__probe(struct bpf_object *obj)
{
int err = 0;
@@ -231,6 +621,18 @@ int bpf__probe(struct bpf_object *obj)
pr_debug("bpf_probe: failed to apply perf probe events");
goto out;
}
+
+ /*
+ * After probing, let's consider prologue, which
+ * adds program fetcher to BPF programs.
+ *
+ * hook_load_preprocessorr() hooks pre-processor
+ * to bpf_program, let it generate prologue
+ * dynamically during loading.
+ */
+ err = hook_load_preprocessor(prog);
+ if (err)
+ goto out;
}
out:
return err < 0 ? err : 0;
@@ -314,7 +716,14 @@ int bpf__foreach_tev(struct bpf_object *obj,
for (i = 0; i < pev->ntevs; i++) {
tev = &pev->tevs[i];
- fd = bpf_program__fd(prog);
+ if (priv->need_prologue) {
+ int type = priv->type_mapping[i];
+
+ fd = bpf_program__nth_fd(prog, type);
+ } else {
+ fd = bpf_program__fd(prog);
+ }
+
if (fd < 0) {
pr_debug("bpf: failed to get file descriptor\n");
return fd;
@@ -340,6 +749,10 @@ static const char *bpf_loader_strerror_table[NR_ERRNO] = {
[ERRCODE_OFFSET(EVENTNAME)] = "No event name found in config string",
[ERRCODE_OFFSET(INTERNAL)] = "BPF loader internal error",
[ERRCODE_OFFSET(COMPILE)] = "Error when compiling BPF scriptlet",
+ [ERRCODE_OFFSET(PROGCONF_TERM)] = "Invalid program config term in config string",
+ [ERRCODE_OFFSET(PROLOGUE)] = "Failed to generate prologue",
+ [ERRCODE_OFFSET(PROLOGUE2BIG)] = "Prologue too big for program",
+ [ERRCODE_OFFSET(PROLOGUEOOB)] = "Offset out of bound for prologue",
};
static int
@@ -420,7 +833,11 @@ 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 \"*\"'");
+ case BPF_LOADER_ERRNO__PROGCONF_TERM: {
+ scnprintf(buf, size, "%s (add -v to see detail)", emsg);
+ break;
+ }
+ bpf__strerror_entry(EEXIST, "Probe point exist. Try 'perf probe -d \"*\"' and set 'force=yes'");
bpf__strerror_entry(EACCES, "You need to be root");
bpf__strerror_entry(EPERM, "You need to be root, and /proc/sys/kernel/kptr_restrict should be 0");
bpf__strerror_entry(ENOENT, "You need to check probing points in BPF file");