From: Yafang Shao <laoar.shao@gmail.com>
To: ast@kernel.org, daniel@iogearbox.net, andrii@kernel.org,
martin.lau@linux.dev, song@kernel.org, yhs@fb.com,
john.fastabend@gmail.com, kpsingh@kernel.org, sdf@google.com,
haoluo@google.com, jolsa@kernel.org, quentin@isovalent.com
Cc: bpf@vger.kernel.org, Yafang Shao <laoar.shao@gmail.com>
Subject: [PATCH bpf-next 5/6] bpf: Support ->fill_link_info for perf_event
Date: Fri, 2 Jun 2023 08:52:38 +0000 [thread overview]
Message-ID: <20230602085239.91138-6-laoar.shao@gmail.com> (raw)
In-Reply-To: <20230602085239.91138-1-laoar.shao@gmail.com>
By adding support for ->fill_link_info to the perf_event link, users will
be able to inspect it using `bpftool link show`. While users can currently
access this information via `bpftool perf show`, consolidating the link
information for all link types in one place would be more convenient.
Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
---
include/uapi/linux/bpf.h | 6 ++++++
kernel/bpf/syscall.c | 45 ++++++++++++++++++++++++++++++++++++++++++
tools/include/uapi/linux/bpf.h | 6 ++++++
3 files changed, 57 insertions(+)
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index 22c8168..87ecf8b 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -6442,6 +6442,12 @@ struct bpf_link_info {
__u64 addrs;
__u32 count;
} kprobe_multi;
+ struct {
+ __aligned_u64 name; /* in/out: symbol name buffer ptr */
+ __u64 addr;
+ __u32 name_len;
+ __u32 offset;
+ } perf_event;
};
} __attribute__((aligned(8)));
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index 80c9ec0..da2de8e 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -3303,9 +3303,54 @@ static void bpf_perf_link_dealloc(struct bpf_link *link)
kfree(perf_link);
}
+static int bpf_perf_link_fill_link_info(const struct bpf_link *link,
+ struct bpf_link_info *info)
+{
+ struct bpf_perf_link *perf_link = container_of(link, struct bpf_perf_link, link);
+ char __user *ubuf = u64_to_user_ptr(info->perf_event.name);
+ u32 ulen = info->perf_event.name_len;
+ const struct perf_event *event;
+ u64 probe_offset, probe_addr;
+ u32 prog_id, fd_type;
+ const char *buf;
+ size_t len;
+ int err;
+
+ if (!ulen ^ !ubuf)
+ return -EINVAL;
+ if (!ubuf)
+ return 0;
+
+ event = perf_get_event(perf_link->perf_file);
+ if (IS_ERR(event))
+ return PTR_ERR(event);
+
+ err = bpf_get_perf_event_info(event, &prog_id, &fd_type,
+ &buf, &probe_offset,
+ &probe_addr);
+ if (err)
+ return err;
+
+ len = strlen(buf);
+ if (buf) {
+ err = bpf_copy_to_user(ubuf, buf, ulen, len);
+ if (err)
+ return err;
+ } else {
+ char zero = '\0';
+
+ if (put_user(zero, ubuf))
+ return -EFAULT;
+ }
+ info->perf_event.addr = probe_addr;
+ info->perf_event.offset = probe_offset;
+ return 0;
+}
+
static const struct bpf_link_ops bpf_perf_link_lops = {
.release = bpf_perf_link_release,
.dealloc = bpf_perf_link_dealloc,
+ .fill_link_info = bpf_perf_link_fill_link_info,
};
static int bpf_perf_link_attach(const union bpf_attr *attr, struct bpf_prog *prog)
diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
index 22c8168..87ecf8b 100644
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h
@@ -6442,6 +6442,12 @@ struct bpf_link_info {
__u64 addrs;
__u32 count;
} kprobe_multi;
+ struct {
+ __aligned_u64 name; /* in/out: symbol name buffer ptr */
+ __u64 addr;
+ __u32 name_len;
+ __u32 offset;
+ } perf_event;
};
} __attribute__((aligned(8)));
--
1.8.3.1
next prev parent reply other threads:[~2023-06-02 8:52 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-06-02 8:52 [PATCH bpf-next 0/6] bpf: Support ->fill_link_info for kprobe prog Yafang Shao
2023-06-02 8:52 ` [PATCH bpf-next 1/6] bpf: Support ->fill_link_info for kprobe_multi Yafang Shao
2023-06-02 16:45 ` Stanislav Fomichev
2023-06-04 3:21 ` Yafang Shao
2023-06-03 6:38 ` kernel test robot
2023-06-04 3:22 ` Yafang Shao
2023-06-02 8:52 ` [PATCH bpf-next 2/6] bpftool: Show probed function in kprobe_multi link info Yafang Shao
2023-06-02 20:36 ` Alexei Starovoitov
2023-06-04 3:24 ` Yafang Shao
2023-06-02 22:16 ` Andrii Nakryiko
2023-06-04 3:26 ` Yafang Shao
2023-06-02 8:52 ` [PATCH bpf-next 3/6] bpf: Always expose the probed address Yafang Shao
2023-06-02 8:52 ` [PATCH bpf-next 4/6] bpf: Add a common helper bpf_copy_to_user() Yafang Shao
2023-06-02 8:52 ` Yafang Shao [this message]
2023-06-02 22:19 ` [PATCH bpf-next 5/6] bpf: Support ->fill_link_info for perf_event Andrii Nakryiko
2023-06-04 3:28 ` Yafang Shao
2023-06-02 8:52 ` [PATCH bpf-next 6/6] bpftool: Show probed function in perf_event link info Yafang Shao
2023-06-02 20:38 ` Alexei Starovoitov
2023-06-04 3:23 ` Yafang Shao
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