#include <linux/bpf.h>
#include <bpf/libbpf.h>
#include <bpf/bpf.h>
+#include <linux/filter.h>
#include <linux/err.h>
#include <linux/kernel.h>
#include <linux/string.h>
struct bpf_insn *insns_buf;
int nr_types;
int *type_mapping;
+ int *prologue_fds;
};
struct bpf_perf_object {
struct bpf_object *obj;
};
+struct bpf_preproc_result {
+ struct bpf_insn *new_insn_ptr;
+ int new_insn_cnt;
+};
+
static LIST_HEAD(bpf_objects_list);
static struct hashmap *bpf_program_hash;
static struct hashmap *bpf_map_hash;
(perf_obj) = (tmp), (tmp) = bpf_perf_object__next(tmp))
static bool libbpf_initialized;
+static int libbpf_sec_handler;
static int bpf_perf_object__add(struct bpf_object *obj)
{
return perf_obj ? 0 : -ENOMEM;
}
+static void *program_priv(const struct bpf_program *prog)
+{
+ void *priv;
+
+ if (IS_ERR_OR_NULL(bpf_program_hash))
+ return NULL;
+ if (!hashmap__find(bpf_program_hash, prog, &priv))
+ return NULL;
+ return priv;
+}
+
+static struct bpf_insn prologue_init_insn[] = {
+ BPF_MOV64_IMM(BPF_REG_2, 0),
+ BPF_MOV64_IMM(BPF_REG_3, 0),
+ BPF_MOV64_IMM(BPF_REG_4, 0),
+ BPF_MOV64_IMM(BPF_REG_5, 0),
+};
+
+static int libbpf_prog_prepare_load_fn(struct bpf_program *prog,
+ struct bpf_prog_load_opts *opts __maybe_unused,
+ long cookie __maybe_unused)
+{
+ size_t init_size_cnt = ARRAY_SIZE(prologue_init_insn);
+ size_t orig_insn_cnt, insn_cnt, init_size, orig_size;
+ struct bpf_prog_priv *priv = program_priv(prog);
+ const struct bpf_insn *orig_insn;
+ struct bpf_insn *insn;
+
+ if (IS_ERR_OR_NULL(priv)) {
+ pr_debug("bpf: failed to get private field\n");
+ return -BPF_LOADER_ERRNO__INTERNAL;
+ }
+
+ if (!priv->need_prologue)
+ return 0;
+
+ /* prepend initialization code to program instructions */
+ orig_insn = bpf_program__insns(prog);
+ orig_insn_cnt = bpf_program__insn_cnt(prog);
+ init_size = init_size_cnt * sizeof(*insn);
+ orig_size = orig_insn_cnt * sizeof(*insn);
+
+ insn_cnt = orig_insn_cnt + init_size_cnt;
+ insn = malloc(insn_cnt * sizeof(*insn));
+ if (!insn)
+ return -ENOMEM;
+
+ memcpy(insn, prologue_init_insn, init_size);
+ memcpy((char *) insn + init_size, orig_insn, orig_size);
+ bpf_program__set_insns(prog, insn, insn_cnt);
+ return 0;
+}
+
static int libbpf_init(void)
{
+ LIBBPF_OPTS(libbpf_prog_handler_opts, handler_opts,
+ .prog_prepare_load_fn = libbpf_prog_prepare_load_fn,
+ );
+
if (libbpf_initialized)
return 0;
libbpf_set_print(libbpf_perf_print);
+ libbpf_sec_handler = libbpf_register_prog_handler(NULL, BPF_PROG_TYPE_KPROBE,
+ 0, &handler_opts);
+ if (libbpf_sec_handler < 0) {
+ pr_debug("bpf: failed to register libbpf section handler: %d\n",
+ libbpf_sec_handler);
+ return -BPF_LOADER_ERRNO__INTERNAL;
+ }
libbpf_initialized = true;
return 0;
}
return obj;
}
+static void close_prologue_programs(struct bpf_prog_priv *priv)
+{
+ struct perf_probe_event *pev;
+ int i, fd;
+
+ if (!priv->need_prologue)
+ return;
+ pev = &priv->pev;
+ for (i = 0; i < pev->ntevs; i++) {
+ fd = priv->prologue_fds[i];
+ if (fd != -1)
+ close(fd);
+ }
+}
+
static void
clear_prog_priv(const struct bpf_program *prog __maybe_unused,
void *_priv)
{
struct bpf_prog_priv *priv = _priv;
+ close_prologue_programs(priv);
cleanup_perf_probe_events(&priv->pev, 1);
zfree(&priv->insns_buf);
+ zfree(&priv->prologue_fds);
zfree(&priv->type_mapping);
zfree(&priv->sys_name);
zfree(&priv->evt_name);
return key1 == key2;
}
-static void *program_priv(const struct bpf_program *prog)
-{
- void *priv;
-
- if (IS_ERR_OR_NULL(bpf_program_hash))
- return NULL;
- if (!hashmap__find(bpf_program_hash, prog, &priv))
- return NULL;
- return priv;
-}
-
static int program_set_priv(struct bpf_program *prog, void *priv)
{
void *old_priv;
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)
+ const struct bpf_insn *orig_insns, int orig_insns_cnt,
+ struct bpf_preproc_result *res)
{
struct bpf_prog_priv *priv = program_priv(prog);
struct probe_trace_event *tev;
res->new_insn_ptr = buf;
res->new_insn_cnt = prologue_cnt + orig_insns_cnt;
- res->pfd = NULL;
return 0;
errout:
struct bpf_prog_priv *priv = program_priv(prog);
struct perf_probe_event *pev;
bool need_prologue = false;
- int err, i;
+ int i;
if (IS_ERR_OR_NULL(priv)) {
pr_debug("Internal error when hook preprocessor\n");
return -ENOMEM;
}
+ priv->prologue_fds = malloc(sizeof(int) * pev->ntevs);
+ if (!priv->prologue_fds) {
+ pr_debug("Not enough memory: alloc prologue fds failed\n");
+ return -ENOMEM;
+ }
+ memset(priv->prologue_fds, -1, sizeof(int) * pev->ntevs);
+
priv->type_mapping = malloc(sizeof(int) * pev->ntevs);
if (!priv->type_mapping) {
pr_debug("Not enough memory: alloc type_mapping failed\n");
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;
+ return map_prologue(pev, priv->type_mapping, &priv->nr_types);
}
int bpf__probe(struct bpf_object *obj)
return ret;
}
+static int bpf_object__load_prologue(struct bpf_object *obj)
+{
+ int init_cnt = ARRAY_SIZE(prologue_init_insn);
+ const struct bpf_insn *orig_insns;
+ struct bpf_preproc_result res;
+ struct perf_probe_event *pev;
+ struct bpf_program *prog;
+ int orig_insns_cnt;
+
+ bpf_object__for_each_program(prog, obj) {
+ struct bpf_prog_priv *priv = program_priv(prog);
+ int err, i, fd;
+
+ if (IS_ERR_OR_NULL(priv)) {
+ pr_debug("bpf: failed to get private field\n");
+ return -BPF_LOADER_ERRNO__INTERNAL;
+ }
+
+ if (!priv->need_prologue)
+ continue;
+
+ /*
+ * For each program that needs prologue we do following:
+ *
+ * - take its current instructions and use them
+ * to generate the new code with prologue
+ * - load new instructions with bpf_prog_load
+ * and keep the fd in prologue_fds
+ * - new fd will be used in bpf__foreach_event
+ * to connect this program with perf evsel
+ */
+ orig_insns = bpf_program__insns(prog);
+ orig_insns_cnt = bpf_program__insn_cnt(prog);
+
+ pev = &priv->pev;
+ for (i = 0; i < pev->ntevs; i++) {
+ /*
+ * Skipping artificall prologue_init_insn instructions
+ * (init_cnt), so the prologue can be generated instead
+ * of them.
+ */
+ err = preproc_gen_prologue(prog, i,
+ orig_insns + init_cnt,
+ orig_insns_cnt - init_cnt,
+ &res);
+ if (err)
+ return err;
+
+ fd = bpf_prog_load(bpf_program__get_type(prog),
+ bpf_program__name(prog), "GPL",
+ res.new_insn_ptr,
+ res.new_insn_cnt, NULL);
+ if (fd < 0) {
+ char bf[128];
+
+ libbpf_strerror(-errno, bf, sizeof(bf));
+ pr_debug("bpf: load objects with prologue failed: err=%d: (%s)\n",
+ -errno, bf);
+ return -errno;
+ }
+ priv->prologue_fds[i] = fd;
+ }
+ /*
+ * We no longer need the original program,
+ * we can unload it.
+ */
+ bpf_program__unload(prog);
+ }
+ return 0;
+}
+
int bpf__load(struct bpf_object *obj)
{
int err;
pr_debug("bpf: load objects failed: err=%d: (%s)\n", err, bf);
return err;
}
- return 0;
+ return bpf_object__load_prologue(obj);
}
int bpf__foreach_event(struct bpf_object *obj,
for (i = 0; i < pev->ntevs; i++) {
tev = &pev->tevs[i];
- if (priv->need_prologue) {
- int type = priv->type_mapping[i];
-
- fd = bpf_program__nth_fd(prog, type);
- } else {
+ if (priv->need_prologue)
+ fd = priv->prologue_fds[i];
+ else
fd = bpf_program__fd(prog);
- }
if (fd < 0) {
pr_debug("bpf: failed to get file descriptor\n");
projects / people / ms / linux.git / commitdiff
