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");