[PATCH 5/8] libbpf: Add support to attach multiple [ku]probes
From: Jiri Olsa <hidden>
Date: 2021-11-24 08:43:25
Also in:
bpf, lkml
Subsystem:
bpf [general] (safe dynamic programs and tools), bpf [library] (libbpf), the rest · Maintainers:
Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko, Eduard Zingerman, Kumar Kartikeya Dwivedi, Linus Torvalds
Adding support to attach multiple [ku]probes.
Extending both bpf_kprobe_opts and bpf_uprobe_opts structs
with config values to define multiple probes within single
bpf_program__attach_[ku]probe_opts call.
For mutiple probes in bpf_program__attach_kprobe_opts function
the 'func_name' argument is ignored and probes are defined in
bpf_kprobe_opts struct with:
struct {
/* probes count */
__u32 cnt;
/* function names array */
char **funcs;
/* address/offset values array */
union {
__u64 *addrs;
__u64 *offs;
};
} multi;
For mutiple probes in bpf_program__attach_uprobe_opts function
both 'binary_path' and 'func_offset' arguments are ignored and
probes are defined in bpf_kprobe_opts struct with:
/* multi uprobe values */
struct {
/* probes count */
__u32 cnt;
/* paths names array */
const char **paths;
/* offsets values array */
__u64 *offs;
} multi;
The multiple probes attachment is enabled when multi.cnt != 0.
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
---
tools/include/uapi/linux/perf_event.h | 1 +
tools/lib/bpf/libbpf.c | 30 +++++++++++++++++++++++++--
tools/lib/bpf/libbpf.h | 25 ++++++++++++++++++++--
3 files changed, 52 insertions(+), 4 deletions(-)
diff --git a/tools/include/uapi/linux/perf_event.h b/tools/include/uapi/linux/perf_event.h
index bd8860eeb291..eea80709d1ed 100644
--- a/tools/include/uapi/linux/perf_event.h
+++ b/tools/include/uapi/linux/perf_event.h@@ -414,6 +414,7 @@ struct perf_event_attr { union { __u32 wakeup_events; /* wakeup every n events */ __u32 wakeup_watermark; /* bytes before wakeup */ + __u32 probe_cnt; /* number of [k,u] probes */ }; __u32 bp_type;
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 34219a0c39a7..b570e93de735 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c@@ -9631,6 +9631,11 @@ struct perf_event_open_args { uint64_t offset; int pid; size_t ref_ctr_off; + struct { + __u32 probe_cnt; + __u64 config1; + __u64 config2; + } multi; }; static int perf_event_open_probe(bool uprobe, struct perf_event_open_args *args)
@@ -9667,8 +9672,15 @@ static int perf_event_open_probe(bool uprobe, struct perf_event_open_args *args) attr.size = sizeof(attr); attr.type = type; attr.config |= (__u64)ref_ctr_off << PERF_UPROBE_REF_CTR_OFFSET_SHIFT; - attr.config1 = ptr_to_u64(args->name); /* kprobe_func or uprobe_path */ - attr.config2 = args->offset; /* kprobe_addr or probe_offset */ + + if (args->multi.probe_cnt) { + attr.probe_cnt = args->multi.probe_cnt; + attr.config1 = args->multi.config1; + attr.config2 = args->multi.config2; + } else { + attr.config1 = ptr_to_u64(args->name); /* kprobe_func or uprobe_path */ + attr.config2 = args->offset; /* kprobe_addr or probe_offset */ + } /* pid filter is meaningful only for uprobes */ pfd = syscall(__NR_perf_event_open, &attr,
@@ -9807,7 +9819,14 @@ bpf_program__attach_kprobe_opts(const struct bpf_program *prog, .pid = -1, .ref_ctr_off = 0, }; + __u32 probe_cnt = OPTS_GET(opts, multi.cnt, false); + if (probe_cnt) { + args.multi.probe_cnt = probe_cnt; + args.multi.config1 = ptr_to_u64(OPTS_GET(opts, multi.funcs, false)); + /* multi.addrs and multi.offs share the same array */ + args.multi.config2 = ptr_to_u64(OPTS_GET(opts, multi.addrs, false)); + } pfd = perf_event_open_probe(false /* uprobe */, &args); } else { char probe_name[256];
@@ -10006,6 +10025,13 @@ bpf_program__attach_uprobe_opts(const struct bpf_program *prog, pid_t pid, .pid = pid, .ref_ctr_off = ref_ctr_off, }; + __u32 probe_cnt = OPTS_GET(opts, multi.cnt, false); + + if (probe_cnt) { + args.multi.probe_cnt = probe_cnt; + args.multi.config1 = ptr_to_u64(OPTS_GET(opts, multi.paths, false)); + args.multi.config2 = ptr_to_u64(OPTS_GET(opts, multi.offs, false)); + } pfd = perf_event_open_probe(true /* uprobe */, &args); } else {
diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h
index d02139fec4ac..ae072882b5dd 100644
--- a/tools/lib/bpf/libbpf.h
+++ b/tools/lib/bpf/libbpf.h@@ -321,9 +321,21 @@ struct bpf_kprobe_opts { size_t offset; /* kprobe is return probe */ bool retprobe; + /* multi kprobe values */ + struct { + /* probes count */ + __u32 cnt; + /* function names array */ + char **funcs; + /* address/offset values array */ + union { + __u64 *addrs; + __u64 *offs; + }; + } multi; size_t :0; }; -#define bpf_kprobe_opts__last_field retprobe +#define bpf_kprobe_opts__last_field multi.addrs LIBBPF_API struct bpf_link * bpf_program__attach_kprobe(const struct bpf_program *prog, bool retprobe,
@@ -344,9 +356,18 @@ struct bpf_uprobe_opts { __u64 bpf_cookie; /* uprobe is return probe, invoked at function return time */ bool retprobe; + /* multi uprobe values */ + struct { + /* probes count */ + __u32 cnt; + /* paths names array */ + const char **paths; + /* offsets values array */ + __u64 *offs; + } multi; size_t :0; }; -#define bpf_uprobe_opts__last_field retprobe +#define bpf_uprobe_opts__last_field multi.offs LIBBPF_API struct bpf_link * bpf_program__attach_uprobe(const struct bpf_program *prog, bool retprobe,
--
2.33.1