From 03dd4cb26d967f9588437b0fc9cc0e8353322bb7 Mon Sep 17 00:00:00 2001 From: André Fabian Silva Delgado Date: Fri, 25 Mar 2016 03:53:42 -0300 Subject: Linux-libre 4.5-gnu --- tools/perf/util/bpf-loader.c | 433 ++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 425 insertions(+), 8 deletions(-) (limited to 'tools/perf/util/bpf-loader.c') diff --git a/tools/perf/util/bpf-loader.c b/tools/perf/util/bpf-loader.c index 4c5041137..540a7efa6 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 #include #include +#include #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; @@ -106,9 +114,177 @@ 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=", + .desc = "Set uprobe target", + .func = prog_config__exec, + }, + { + .key = "module", + .usage = "module= ", + .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) { @@ -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"); -- cgit v1.2.3-54-g00ecf