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Message-Id: <20201022082138.2322434-14-jolsa@kernel.org>
Date: Thu, 22 Oct 2020 10:21:35 +0200
From: Jiri Olsa <jolsa@...nel.org>
To: Alexei Starovoitov <ast@...nel.org>,
Daniel Borkmann <daniel@...earbox.net>,
Andrii Nakryiko <andriin@...com>
Cc: netdev@...r.kernel.org, bpf@...r.kernel.org,
Martin KaFai Lau <kafai@...com>,
Song Liu <songliubraving@...com>, Yonghong Song <yhs@...com>,
John Fastabend <john.fastabend@...il.com>,
KP Singh <kpsingh@...omium.org>, Daniel Xu <dxu@...uu.xyz>,
Steven Rostedt <rostedt@...dmis.org>,
Jesper Brouer <jbrouer@...hat.com>,
Toke Høiland-Jørgensen <toke@...hat.com>,
Viktor Malik <vmalik@...hat.com>
Subject: [RFC bpf-next 13/16] libbpf: Add trampoline batch attach support
Adding trampoline batch attach support so it's possible to use
batch mode to load tracing programs.
Adding trampoline_attach_batch bool to struct bpf_object_open_opts.
When set to true the bpf_object__attach_skeleton will try to load
all tracing programs via batch mode.
Signed-off-by: Jiri Olsa <jolsa@...nel.org>
---
tools/lib/bpf/bpf.c | 12 +++++++
tools/lib/bpf/bpf.h | 1 +
tools/lib/bpf/libbpf.c | 76 +++++++++++++++++++++++++++++++++++++++-
tools/lib/bpf/libbpf.h | 5 ++-
tools/lib/bpf/libbpf.map | 1 +
5 files changed, 93 insertions(+), 2 deletions(-)
diff --git a/tools/lib/bpf/bpf.c b/tools/lib/bpf/bpf.c
index d27e34133973..21fffff5e237 100644
--- a/tools/lib/bpf/bpf.c
+++ b/tools/lib/bpf/bpf.c
@@ -858,6 +858,18 @@ int bpf_raw_tracepoint_open(const char *name, int prog_fd)
return sys_bpf(BPF_RAW_TRACEPOINT_OPEN, &attr, sizeof(attr));
}
+int bpf_trampoline_batch_attach(int *ifds, int *ofds, int count)
+{
+ union bpf_attr attr;
+
+ memset(&attr, 0, sizeof(attr));
+ attr.trampoline_batch.in = ptr_to_u64(ifds);
+ attr.trampoline_batch.out = ptr_to_u64(ofds);
+ attr.trampoline_batch.count = count;
+
+ return sys_bpf(BPF_TRAMPOLINE_BATCH_ATTACH, &attr, sizeof(attr));
+}
+
int bpf_load_btf(const void *btf, __u32 btf_size, char *log_buf, __u32 log_buf_size,
bool do_log)
{
diff --git a/tools/lib/bpf/bpf.h b/tools/lib/bpf/bpf.h
index 875dde20d56e..ba3b0b6e3cb0 100644
--- a/tools/lib/bpf/bpf.h
+++ b/tools/lib/bpf/bpf.h
@@ -235,6 +235,7 @@ LIBBPF_API int bpf_prog_query(int target_fd, enum bpf_attach_type type,
__u32 query_flags, __u32 *attach_flags,
__u32 *prog_ids, __u32 *prog_cnt);
LIBBPF_API int bpf_raw_tracepoint_open(const char *name, int prog_fd);
+LIBBPF_API int bpf_trampoline_batch_attach(int *ifds, int *ofds, int count);
LIBBPF_API int bpf_load_btf(const void *btf, __u32 btf_size, char *log_buf,
__u32 log_buf_size, bool do_log);
LIBBPF_API int bpf_task_fd_query(int pid, int fd, __u32 flags, char *buf,
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 313034117070..584da3b401ac 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -421,6 +421,7 @@ struct bpf_object {
bool loaded;
bool has_subcalls;
+ bool trampoline_attach_batch;
/*
* Information when doing elf related work. Only valid if fd
@@ -6907,6 +6908,9 @@ __bpf_object__open(const char *path, const void *obj_buf, size_t obj_buf_sz,
return ERR_PTR(-ENOMEM);
}
+ obj->trampoline_attach_batch = OPTS_GET(opts, trampoline_attach_batch,
+ false);
+
err = bpf_object__elf_init(obj);
err = err ? : bpf_object__check_endianness(obj);
err = err ? : bpf_object__elf_collect(obj);
@@ -10811,9 +10815,75 @@ int bpf_object__load_skeleton(struct bpf_object_skeleton *s)
return 0;
}
+static bool is_trampoline(const struct bpf_program *prog)
+{
+ return prog->type == BPF_PROG_TYPE_TRACING &&
+ (prog->expected_attach_type == BPF_TRACE_FENTRY ||
+ prog->expected_attach_type == BPF_TRACE_FEXIT);
+}
+
+static int attach_trace_batch(struct bpf_object_skeleton *s)
+{
+ int i, prog_fd, ret = -ENOMEM;
+ int *in_fds, *out_fds, cnt;
+
+ in_fds = calloc(s->prog_cnt, sizeof(in_fds[0]));
+ out_fds = calloc(s->prog_cnt, sizeof(out_fds[0]));
+ if (!in_fds || !out_fds)
+ goto out_clean;
+
+ ret = -EINVAL;
+ for (cnt = 0, i = 0; i < s->prog_cnt; i++) {
+ struct bpf_program *prog = *s->progs[i].prog;
+
+ if (!is_trampoline(prog))
+ continue;
+
+ prog_fd = bpf_program__fd(prog);
+ if (prog_fd < 0) {
+ pr_warn("prog '%s': can't attach before loaded\n", prog->name);
+ goto out_clean;
+ }
+ in_fds[cnt++] = prog_fd;
+ }
+
+ ret = bpf_trampoline_batch_attach(in_fds, out_fds, cnt);
+ if (ret)
+ goto out_clean;
+
+ for (cnt = 0, i = 0; i < s->prog_cnt; i++) {
+ struct bpf_program *prog = *s->progs[i].prog;
+ struct bpf_link **linkp = s->progs[i].link;
+ struct bpf_link *link;
+
+ if (!is_trampoline(prog))
+ continue;
+
+ link = calloc(1, sizeof(*link));
+ if (!link)
+ goto out_clean;
+
+ link->detach = &bpf_link__detach_fd;
+ link->fd = out_fds[cnt++];
+ *linkp = link;
+ }
+
+out_clean:
+ free(in_fds);
+ free(out_fds);
+ return ret;
+}
+
int bpf_object__attach_skeleton(struct bpf_object_skeleton *s)
{
- int i;
+ struct bpf_object *obj = *s->obj;
+ int i, err;
+
+ if (obj->trampoline_attach_batch) {
+ err = attach_trace_batch(s);
+ if (err)
+ return err;
+ }
for (i = 0; i < s->prog_cnt; i++) {
struct bpf_program *prog = *s->progs[i].prog;
@@ -10823,6 +10893,10 @@ int bpf_object__attach_skeleton(struct bpf_object_skeleton *s)
if (!prog->load)
continue;
+ /* Program was attached via batch mode. */
+ if (obj->trampoline_attach_batch && is_trampoline(prog))
+ continue;
+
sec_def = find_sec_def(prog->sec_name);
if (!sec_def || !sec_def->attach_fn)
continue;
diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h
index 6909ee81113a..66f8e78aa9f8 100644
--- a/tools/lib/bpf/libbpf.h
+++ b/tools/lib/bpf/libbpf.h
@@ -93,8 +93,11 @@ struct bpf_object_open_opts {
* system Kconfig for CONFIG_xxx externs.
*/
const char *kconfig;
+ /* Attach trampolines via batch mode.
+ */
+ bool trampoline_attach_batch;
};
-#define bpf_object_open_opts__last_field kconfig
+#define bpf_object_open_opts__last_field trampoline_attach_batch
LIBBPF_API struct bpf_object *bpf_object__open(const char *path);
LIBBPF_API struct bpf_object *
diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map
index 4ebfadf45b47..5a5ce921956d 100644
--- a/tools/lib/bpf/libbpf.map
+++ b/tools/lib/bpf/libbpf.map
@@ -336,4 +336,5 @@ LIBBPF_0.2.0 {
perf_buffer__epoll_fd;
perf_buffer__consume_buffer;
xsk_socket__create_shared;
+ bpf_trampoline_batch_attach;
} LIBBPF_0.1.0;
--
2.26.2
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