[PATCH bpf-next 4/5] bpf: Attach a cookie to a BPF program.

[Kui-Feng Lee <kuifeng@fb.com>]

Extend bpf() to attach a tracing program with a cookie by adding a
bpf_cookie field to bpf_attr for raw tracepoints.

Signed-off-by: Kui-Feng Lee <kuifeng@fb.com>
---
 include/linux/bpf.h            |  1 +
 include/uapi/linux/bpf.h       |  1 +
 kernel/bpf/syscall.c           | 12 ++++++++----
 tools/include/uapi/linux/bpf.h |  1 +
 tools/lib/bpf/bpf.c            | 14 ++++++++++++++
 tools/lib/bpf/bpf.h            |  1 +
 tools/lib/bpf/libbpf.map       |  1 +
 7 files changed, 27 insertions(+), 4 deletions(-)

diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index 37353745fee5..d5196514e9bd 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -1004,6 +1004,7 @@ struct bpf_prog_aux {
 		struct work_struct work;
 		struct rcu_head	rcu;
 	};
+	u64 cookie;
 };
 
 struct bpf_array_aux {
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index 16a7574292a5..3fa27346ab4b 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -1425,6 +1425,7 @@ union bpf_attr {
 	struct { /* anonymous struct used by BPF_RAW_TRACEPOINT_OPEN command */
 		__u64 name;
 		__u32 prog_fd;
+		__u64 bpf_cookie;
 	} raw_tracepoint;
 
 	struct { /* anonymous struct for BPF_BTF_LOAD */
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index 72ce1edde950..79d057918c76 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -2696,7 +2696,8 @@ static const struct bpf_link_ops bpf_tracing_link_lops = {
 
 static int bpf_tracing_prog_attach(struct bpf_prog *prog,
 				   int tgt_prog_fd,
-				   u32 btf_id)
+				   u32 btf_id,
+				   u64 bpf_cookie)
 {
 	struct bpf_link_primer link_primer;
 	struct bpf_prog *tgt_prog = NULL;
@@ -2832,6 +2833,8 @@ static int bpf_tracing_prog_attach(struct bpf_prog *prog,
 	if (err)
 		goto out_unlock;
 
+	prog->aux->cookie = bpf_cookie;
+
 	err = bpf_trampoline_link_prog(prog, tr);
 	if (err) {
 		bpf_link_cleanup(&link_primer);
@@ -3017,7 +3020,7 @@ static int bpf_perf_link_attach(const union bpf_attr *attr, struct bpf_prog *pro
 }
 #endif /* CONFIG_PERF_EVENTS */
 
-#define BPF_RAW_TRACEPOINT_OPEN_LAST_FIELD raw_tracepoint.prog_fd
+#define BPF_RAW_TRACEPOINT_OPEN_LAST_FIELD raw_tracepoint.bpf_cookie
 
 static int bpf_raw_tracepoint_open(const union bpf_attr *attr)
 {
@@ -3052,7 +3055,7 @@ static int bpf_raw_tracepoint_open(const union bpf_attr *attr)
 			tp_name = prog->aux->attach_func_name;
 			break;
 		}
-		err = bpf_tracing_prog_attach(prog, 0, 0);
+		err = bpf_tracing_prog_attach(prog, 0, 0, attr->raw_tracepoint.bpf_cookie);
 		if (err >= 0)
 			return err;
 		goto out_put_prog;
@@ -4244,7 +4247,8 @@ static int tracing_bpf_link_attach(const union bpf_attr *attr, bpfptr_t uattr,
 	else if (prog->type == BPF_PROG_TYPE_EXT)
 		return bpf_tracing_prog_attach(prog,
 					       attr->link_create.target_fd,
-					       attr->link_create.target_btf_id);
+					       attr->link_create.target_btf_id,
+					       0);
 	return -EINVAL;
 }
 
diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
index 16a7574292a5..3fa27346ab4b 100644
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h
@@ -1425,6 +1425,7 @@ union bpf_attr {
 	struct { /* anonymous struct used by BPF_RAW_TRACEPOINT_OPEN command */
 		__u64 name;
 		__u32 prog_fd;
+		__u64 bpf_cookie;
 	} raw_tracepoint;
 
 	struct { /* anonymous struct for BPF_BTF_LOAD */
diff --git a/tools/lib/bpf/bpf.c b/tools/lib/bpf/bpf.c
index 418b259166f8..c28b017de515 100644
--- a/tools/lib/bpf/bpf.c
+++ b/tools/lib/bpf/bpf.c
@@ -1131,6 +1131,20 @@ int bpf_raw_tracepoint_open(const char *name, int prog_fd)
 	return libbpf_err_errno(fd);
 }
 
+int bpf_raw_tracepoint_cookie_open(const char *name, int prog_fd, __u64 bpf_cookie)
+{
+	union bpf_attr attr;
+	int fd;
+
+	memset(&attr, 0, sizeof(attr));
+	attr.raw_tracepoint.name = ptr_to_u64(name);
+	attr.raw_tracepoint.prog_fd = prog_fd;
+	attr.raw_tracepoint.bpf_cookie = bpf_cookie;
+
+	fd = sys_bpf_fd(BPF_RAW_TRACEPOINT_OPEN, &attr, sizeof(attr));
+	return libbpf_err_errno(fd);
+}
+
 int bpf_btf_load(const void *btf_data, size_t btf_size, const struct bpf_btf_load_opts *opts)
 {
 	const size_t attr_sz = offsetofend(union bpf_attr, btf_log_level);
diff --git a/tools/lib/bpf/bpf.h b/tools/lib/bpf/bpf.h
index c2e8327010f9..c3d2c6a4cb15 100644
--- a/tools/lib/bpf/bpf.h
+++ b/tools/lib/bpf/bpf.h
@@ -475,6 +475,7 @@ 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_raw_tracepoint_cookie_open(const char *name, int prog_fd, __u64 bpf_cookie);
 LIBBPF_API int bpf_task_fd_query(int pid, int fd, __u32 flags, char *buf,
 				 __u32 *buf_len, __u32 *prog_id, __u32 *fd_type,
 				 __u64 *probe_offset, __u64 *probe_addr);
diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map
index e10f0822845a..05af5bb8de92 100644
--- a/tools/lib/bpf/libbpf.map
+++ b/tools/lib/bpf/libbpf.map
@@ -432,6 +432,7 @@ LIBBPF_0.7.0 {
 		bpf_xdp_detach;
 		bpf_xdp_query;
 		bpf_xdp_query_id;
+		bpf_raw_tracepoint_cookie_open;
 		libbpf_probe_bpf_helper;
 		libbpf_probe_bpf_map_type;
 		libbpf_probe_bpf_prog_type;
-- 
2.30.2