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, 21 insertions, 1 deletions

diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index d21deb46f49f..8790b3962e4b 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -1039,6 +1039,7 @@ enum bpf_attach_type {
 	BPF_NETFILTER,
 	BPF_TCX_INGRESS,
 	BPF_TCX_EGRESS,
+	BPF_TRACE_UPROBE_MULTI,
 	__MAX_BPF_ATTACH_TYPE
 };
 
@@ -1057,6 +1058,7 @@ enum bpf_link_type {
 	BPF_LINK_TYPE_STRUCT_OPS = 9,
 	BPF_LINK_TYPE_NETFILTER = 10,
 	BPF_LINK_TYPE_TCX = 11,
+	BPF_LINK_TYPE_UPROBE_MULTI = 12,
 	MAX_BPF_LINK_TYPE,
 };
 
@@ -1186,7 +1188,16 @@ enum bpf_perf_event_type {
 /* link_create.kprobe_multi.flags used in LINK_CREATE command for
  * BPF_TRACE_KPROBE_MULTI attach type to create return probe.
  */
-#define BPF_F_KPROBE_MULTI_RETURN	(1U << 0)
+enum {
+	BPF_F_KPROBE_MULTI_RETURN = (1U << 0)
+};
+
+/* link_create.uprobe_multi.flags used in LINK_CREATE command for
+ * BPF_TRACE_UPROBE_MULTI attach type to create return probe.
+ */
+enum {
+	BPF_F_UPROBE_MULTI_RETURN = (1U << 0)
+};
 
 /* link_create.netfilter.flags used in LINK_CREATE command for
  * BPF_PROG_TYPE_NETFILTER to enable IP packet defragmentation.
@@ -1624,6 +1635,15 @@ union bpf_attr {
 				};
 				__u64		expected_revision;
 			} tcx;
+			struct {
+				__aligned_u64	path;
+				__aligned_u64	offsets;
+				__aligned_u64	ref_ctr_offsets;
+				__aligned_u64	cookies;
+				__u32		cnt;
+				__u32		flags;
+				__u32		pid;
+			} uprobe_multi;
 		};
 	} link_create;