On 6/12/23 8:16 AM, Yafang Shao wrote:
By introducing support for ->fill_link_info to the perf_event link, users
gain the ability to inspect it using `bpftool link show`. While the current
approach involves accessing this information via `bpftool perf show`,
consolidating link information for all link types in one place offers
greater convenience. Additionally, this patch extends support to the
generic perf event, which is not currently accommodated by
`bpftool perf show`. While only the perf type and config are exposed to
userspace, other attributes such as sample_period and sample_freq are
ignored. It's important to note that if kptr_restrict is not permitted, the
probed address will not be exposed, maintaining security measures.
A new enum bpf_link_perf_event_type is introduced to help the user
understand which struct is relevant.
Signed-off-by: Yafang Shao <laoar.shao@xxxxxxxxx>
---
include/uapi/linux/bpf.h | 32 +++++++++++
kernel/bpf/syscall.c | 124 +++++++++++++++++++++++++++++++++++++++++
tools/include/uapi/linux/bpf.h | 32 +++++++++++
3 files changed, 188 insertions(+)
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index 23691ea..8d4556e 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -1056,6 +1056,16 @@ enum bpf_link_type {
MAX_BPF_LINK_TYPE,
};
+enum bpf_perf_link_type {
+ BPF_PERF_LINK_UNSPEC = 0,
+ BPF_PERF_LINK_UPROBE = 1,
+ BPF_PERF_LINK_KPROBE = 2,
+ BPF_PERF_LINK_TRACEPOINT = 3,
+ BPF_PERF_LINK_PERF_EVENT = 4,
+
+ MAX_BPF_LINK_PERF_EVENT_TYPE,
+};
+
/* cgroup-bpf attach flags used in BPF_PROG_ATTACH command
*
* NONE(default): No further bpf programs allowed in the subtree.
@@ -6443,7 +6453,29 @@ struct bpf_link_info {
__u32 count;
__u32 flags;
} kprobe_multi;
+ struct {
+ __u64 config;
+ __u32 type;
+ } perf_event; /* BPF_LINK_PERF_EVENT_PERF_EVENT */
+ struct {
+ __aligned_u64 file_name; /* in/out: buff ptr */
+ __u32 name_len;
+ __u32 offset; /* offset from name */
+ __u32 flags;
+ } uprobe; /* BPF_LINK_PERF_EVENT_UPROBE */
+ struct {
+ __aligned_u64 func_name; /* in/out: buff ptr */
+ __u32 name_len;
+ __u32 offset; /* offset from name */
+ __u64 addr;
+ __u32 flags;
+ } kprobe; /* BPF_LINK_PERF_EVENT_KPROBE */
+ struct {
+ __aligned_u64 tp_name; /* in/out: buff ptr */
+ __u32 name_len;
+ } tracepoint; /* BPF_LINK_PERF_EVENT_TRACEPOINT */
};
+ __u32 perf_link_type; /* enum bpf_perf_link_type */
I think put perf_link_type into each indivual struct is better.
It won't increase the bpf_link_info struct size. It will allow
extensions for all structs in the big union (raw_tracepoint,
tracing, cgroup, iter, ..., kprobe_multi, ...) etc.
} __attribute__((aligned(8)));
/* User bpf_sock_addr struct to access socket fields and sockaddr struct passed
[...]
