Merge branch 'bpf-add-multi-uprobe-link'

Jiri Olsa says:

====================
bpf: Add multi uprobe link

hi,
this patchset is adding support to attach multiple uprobes and usdt probes
through new uprobe_multi link.

The current uprobe is attached through the perf event and attaching many
uprobes takes a lot of time because of that.

The main reason is that we need to install perf event for each probed function
and profile shows perf event installation (perf_install_in_context) as culprit.

The new uprobe_multi link just creates raw uprobes and attaches the bpf
program to them without perf event being involved.

In addition to being faster we also save file descriptors. For the current
uprobe attach we use extra perf event fd for each probed function. The new
link just need one fd that covers all the functions we are attaching to.

v7 changes:
  - fixed task release on error path and re-org the error
    path to be more straightforward [Yonghong]
  - re-organized uprobe_prog_run locking to follow general pattern
    and removed might_fault check as it's not needed in uprobe/task
    context [Yonghong]

There's support for bpftrace [2] and tetragon [1].

Also available at:
  https://git.kernel.org/pub/scm/linux/kernel/git/jolsa/perf.git
  uprobe_multi

thanks,
jirka

[1] https://github.com/cilium/tetragon/pull/936
[2] https://github.com/iovisor/bpftrace/compare/master...olsajiri:bpftrace:uprobe_multi
[3] https://lore.kernel.org/bpf/20230628115329.248450-1-laoar.shao@gmail.com/
---
====================

Link: https://lore.kernel.org/r/20230809083440.3209381-1-jolsa@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

1 files changed, 10 insertions, 1 deletions

diff --git a/tools/lib/bpf/bpf.h b/tools/lib/bpf/bpf.h
index 044a74ffc38a..74c2887cfd24 100644
--- a/tools/lib/bpf/bpf.h
+++ b/tools/lib/bpf/bpf.h
@@ -393,6 +393,15 @@ struct bpf_link_create_opts {
 			const __u64 *cookies;
 		} kprobe_multi;
 		struct {
+			__u32 flags;
+			__u32 cnt;
+			const char *path;
+			const unsigned long *offsets;
+			const unsigned long *ref_ctr_offsets;
+			const __u64 *cookies;
+			__u32 pid;
+		} uprobe_multi;
+		struct {
 			__u64 cookie;
 		} tracing;
 		struct {
@@ -409,7 +418,7 @@ struct bpf_link_create_opts {
 	};
 	size_t :0;
 };
-#define bpf_link_create_opts__last_field kprobe_multi.cookies
+#define bpf_link_create_opts__last_field uprobe_multi.pid
 
 LIBBPF_API int bpf_link_create(int prog_fd, int target_fd,
 			       enum bpf_attach_type attach_type,