Adding support to link multi func tracing program
through link_create interface.
Adding special types for multi func programs:
fentry.multi
fexit.multi
so you can define multi func programs like:
SEC("fentry.multi/bpf_fentry_test*")
int BPF_PROG(test1, __u64 a, __u64 b, __u64 c, __u64 d, __u64 e, __u64 f)
that defines test1 to be attached to bpf_fentry_test* functions.
The test1 program is loaded with BPF_F_MULTI_FUNC flag.
If functions are not specified the program needs to be attached
manually.
Adding new btf_ids/btf_ids_cnt fields to bpf_link_create_opts,
that define functions to attach the program to.
Signed-off-by: Jiri Olsa <jolsa@xxxxxxxxxx>
---
tools/lib/bpf/bpf.c | 8 +++++
tools/lib/bpf/bpf.h | 6 +++-
tools/lib/bpf/libbpf.c | 72 ++++++++++++++++++++++++++++++++++++++++++
3 files changed, 85 insertions(+), 1 deletion(-)
diff --git a/tools/lib/bpf/bpf.c b/tools/lib/bpf/bpf.c
index 2401fad090c5..20422d58b945 100644
--- a/tools/lib/bpf/bpf.c
+++ b/tools/lib/bpf/bpf.c
@@ -713,12 +713,20 @@ int bpf_link_create(int prog_fd, int target_fd,
if (!OPTS_ZEROED(opts, perf_event))
return libbpf_err(-EINVAL);
break;
+ case BPF_TRACE_FENTRY:
+ case BPF_TRACE_FEXIT:
+ attr.link_create.multi_btf_ids = (__u64) OPTS_GET(opts, multi.btf_ids, 0);
+ attr.link_create.multi_btf_ids_cnt = OPTS_GET(opts, multi.btf_ids_cnt, 0);
+ if (!OPTS_ZEROED(opts, multi))
+ return libbpf_err(-EINVAL);
+ break;
default:
if (!OPTS_ZEROED(opts, flags))
return libbpf_err(-EINVAL);
break;
}
proceed:
+
fd = sys_bpf(BPF_LINK_CREATE, &attr, sizeof(attr));
return libbpf_err_errno(fd);
}
diff --git a/tools/lib/bpf/bpf.h b/tools/lib/bpf/bpf.h
index 6fffb3cdf39b..2eff99be7069 100644
--- a/tools/lib/bpf/bpf.h
+++ b/tools/lib/bpf/bpf.h
@@ -181,10 +181,14 @@ struct bpf_link_create_opts {
struct {
__u64 bpf_cookie;
} perf_event;
+ struct {
+ __u32 *btf_ids;
+ __u32 btf_ids_cnt;
+ } multi;
};
size_t :0;
};
-#define bpf_link_create_opts__last_field perf_event
+#define bpf_link_create_opts__last_field multi
LIBBPF_API int bpf_link_create(int prog_fd, int target_fd,
enum bpf_attach_type attach_type,
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 88d8825fc6f6..7f717b7755be 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -230,6 +230,7 @@ struct bpf_sec_def {
bool is_attachable;
bool is_attach_btf;
bool is_sleepable;
+ bool is_multi_func;
attach_fn_t attach_fn;
};
@@ -6446,6 +6447,8 @@ __bpf_object__open(const char *path, const void *obj_buf, size_t obj_buf_sz,
if (prog->sec_def->is_sleepable)
prog->prog_flags |= BPF_F_SLEEPABLE;
+ if (prog->sec_def->is_multi_func)
+ prog->prog_flags |= BPF_F_MULTI_FUNC;
bpf_program__set_type(prog, prog->sec_def->prog_type);
bpf_program__set_expected_attach_type(prog,
prog->sec_def->expected_attach_type);
@@ -7915,6 +7918,8 @@ static struct bpf_link *attach_raw_tp(const struct bpf_sec_def *sec,
struct bpf_program *prog);
static struct bpf_link *attach_trace(const struct bpf_sec_def *sec,
struct bpf_program *prog);
+static struct bpf_link *attach_trace_multi(const struct bpf_sec_def *sec,
+ struct bpf_program *prog);
static struct bpf_link *attach_lsm(const struct bpf_sec_def *sec,
struct bpf_program *prog);
static struct bpf_link *attach_iter(const struct bpf_sec_def *sec,
@@ -7991,6 +7996,14 @@ static const struct bpf_sec_def section_defs[] = {
.attach_fn = attach_iter),
SEC_DEF("syscall", SYSCALL,
.is_sleepable = true),
+ SEC_DEF("fentry.multi/", TRACING,
+ .expected_attach_type = BPF_TRACE_FENTRY,
+ .is_multi_func = true,
+ .attach_fn = attach_trace_multi),
+ SEC_DEF("fexit.multi/", TRACING,
+ .expected_attach_type = BPF_TRACE_FEXIT,
+ .is_multi_func = true,
+ .attach_fn = attach_trace_multi),
BPF_EAPROG_SEC("xdp_devmap/", BPF_PROG_TYPE_XDP,
BPF_XDP_DEVMAP),
BPF_EAPROG_SEC("xdp_cpumap/", BPF_PROG_TYPE_XDP,
@@ -8435,6 +8448,9 @@ static int libbpf_find_attach_btf_id(struct bpf_program *prog, int *btf_obj_fd,
if (!name)
return -EINVAL;
+ if (prog->prog_flags & BPF_F_MULTI_FUNC)
+ return 0;
+
for (i = 0; i < ARRAY_SIZE(section_defs); i++) {
if (!section_defs[i].is_attach_btf)
continue;
@@ -9523,6 +9539,62 @@ static struct bpf_link *bpf_program__attach_btf_id(struct bpf_program *prog)
return (struct bpf_link *)link;
}
+static struct bpf_link *bpf_program__attach_multi(struct bpf_program *prog)
+{
+ char *pattern = prog->sec_name + prog->sec_def->len;
+ DECLARE_LIBBPF_OPTS(bpf_link_create_opts, opts);
+ enum bpf_attach_type attach_type;
+ int prog_fd, link_fd, cnt, err;
+ struct bpf_link *link = NULL;
+ __u32 *ids = NULL;
+
+ prog_fd = bpf_program__fd(prog);
+ if (prog_fd < 0) {
+ pr_warn("prog '%s': can't attach before loaded\n", prog->name);
+ return ERR_PTR(-EINVAL);
+ }
+
+ err = bpf_object__load_vmlinux_btf(prog->obj, true);
+ if (err)
+ return ERR_PTR(err);
+
+ cnt = btf__find_by_glob_kind(prog->obj->btf_vmlinux, BTF_KIND_FUNC,
+ pattern, NULL, &ids);
+ if (cnt <= 0)
+ return ERR_PTR(-EINVAL);
+
+ link = calloc(1, sizeof(*link));
+ if (!link) {
+ err = -ENOMEM;
+ goto out_err;
+ }
+ link->detach = &bpf_link__detach_fd;
+
+ opts.multi.btf_ids = ids;
+ opts.multi.btf_ids_cnt = cnt;
+
+ attach_type = bpf_program__get_expected_attach_type(prog);
+ link_fd = bpf_link_create(prog_fd, 0, attach_type, &opts);
+ if (link_fd < 0) {
+ err = -errno;
+ goto out_err;
+ }
+ link->fd = link_fd;
+ free(ids);
+ return link;
+
+out_err:
+ free(link);
+ free(ids);
+ return ERR_PTR(err);
+}
+
+static struct bpf_link *attach_trace_multi(const struct bpf_sec_def *sec,
+ struct bpf_program *prog)
+{
+ return bpf_program__attach_multi(prog);
+}
+
struct bpf_link *bpf_program__attach_trace(struct bpf_program *prog)
{
return bpf_program__attach_btf_id(prog);
--
2.31.1
