[patch] perf_event_open.2: Document the PERF_EVENT_IOC_QUERY_BPF ioctl

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



The PERF_EVENT_IOC_QUERY_BPF ioctl was introduced in Linux 4.16.

Signed-off-by: Vince Weaver <vincent.weaver@xxxxxxxxx>

diff --git a/man2/perf_event_open.2 b/man2/perf_event_open.2
index b598acf17..a464e95a2 100644
--- a/man2/perf_event_open.2
+++ b/man2/perf_event_open.2
@@ -2945,6 +2945,47 @@ even though the ring-buffer remains empty.
 The argument is an unsigned 32-bit integer.
 A nonzero value pauses the ring-buffer, while a
 zero value resumes the ring-buffer.
+.TP
+.BR PERF_EVENT_IOC_QUERY_BPF " (since Linux 4.16)"
+.\" commit f371b304f12e31fe30207c41ca7754564e0ea4dc
+This allows querying which Berkeley Packet Filter (BPF)
+programs are attached to an existing kprobe tracepoint.
+You can only attach one BPF program per event, but you can
+have multiple events attached to a tracepoint.
+Querying this value on one tracepoint event returns the id
+of all BPF programs in all events attached to the tracepoint.
+You need
+.B CAP_SYS_ADMIN
+privileges to use this ioctl.
+.IP
+The argument is a pointer to a structure
+.in +4n
+.EX
+struct perf_event_query_bpf {
+    __u32    ids_len;
+    __u32    prog_cnt;
+    __u32    ids[0];
+};
+.EE
+.IP
+The
+.I ids_len
+field indicates the number of ids that can fit in the provided
+.I ids
+array.
+The
+.I prog_cnt
+value is filled in by the kernel with the number of attached
+BPF programs.
+The
+.I ids
+array is filled with the id of each attached BPF program.
+If there are more programs than will fit in the array, then the
+kernel will return
+.B ENOSPC
+and
+.I ids_len
+will indicate the number of program IDs that were successfully copied.
 .SS Using prctl(2)
 A process can enable or disable all currently open event groups
 using the
--
To unsubscribe from this list: send the line "unsubscribe linux-man" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html



[Index of Archives]     [Kernel Documentation]     [Netdev]     [Linux Ethernet Bridging]     [Linux Wireless]     [Kernel Newbies]     [Security]     [Linux for Hams]     [Netfilter]     [Bugtraq]     [Yosemite News]     [MIPS Linux]     [ARM Linux]     [Linux RAID]     [Linux Admin]     [Samba]

  Powered by Linux