On 6/20/23 9:30 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_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 | 36 +++++++++++++
kernel/bpf/syscall.c | 115 +++++++++++++++++++++++++++++++++++++++++
tools/include/uapi/linux/bpf.h | 36 +++++++++++++
3 files changed, 187 insertions(+)
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index 23691ea..56528dd 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_event_type {
+ BPF_PERF_EVENT_UNSPEC = 0,
+ BPF_PERF_EVENT_UPROBE = 1,
+ BPF_PERF_EVENT_KPROBE = 2,
+ BPF_PERF_EVENT_TRACEPOINT = 3,
+ BPF_PERF_EVENT_EVENT = 4,
+
+ MAX_BPF_PERF_EVENT_TYPE,
+};
+
/* cgroup-bpf attach flags used in BPF_PROG_ATTACH command
*
* NONE(default): No further bpf programs allowed in the subtree.
@@ -6443,6 +6453,32 @@ struct bpf_link_info {
__u32 count;
__u32 flags;
} kprobe_multi;
+ struct {
+ __u32 type; /* enum bpf_perf_event_type */
Maybe add the following
__u32 :32;
so later on this field can be reused if another u32 is needed in
the future?
+ union {
+ struct {
+ __aligned_u64 file_name; /* in/out */
+ __u32 name_len;
+ __u32 offset;/* offset from file_name */
+ __u32 flags;
+ } uprobe; /* BPF_PERF_EVENT_UPROBE */
+ struct {
+ __aligned_u64 func_name; /* in/out */
+ __u32 name_len;
+ __u32 offset;/* offset from func_name */
+ __u64 addr;
+ __u32 flags;
+ } kprobe; /* BPF_PERF_EVENT_KPROBE */
+ struct {
+ __aligned_u64 tp_name; /* in/out */
+ __u32 name_len;
+ } tracepoint; /* BPF_PERF_EVENT_TRACEPOINT */
+ struct {
+ __u64 config;
+ __u32 type;
+ } event; /* BPF_PERF_EVENT_EVENT */
+ };
+ } perf_event;
};
} __attribute__((aligned(8)));
[...]
