diff options
author | Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> | 2017-03-08 09:26:09 +0100 |
---|---|---|
committer | Arnaldo Carvalho de Melo <acme@redhat.com> | 2017-03-14 19:17:39 +0100 |
commit | 7ab31d94bff96f4f80b38dc5147622b9f3889ac6 (patch) | |
tree | 158fb2762dd41bd84f17ed3fb3c7e5882d5b7009 /tools/perf/util/probe-file.c | |
parent | perf probe: Factor out the ftrace README scanning (diff) | |
download | linux-7ab31d94bff96f4f80b38dc5147622b9f3889ac6.tar.xz linux-7ab31d94bff96f4f80b38dc5147622b9f3889ac6.zip |
perf kretprobes: Offset from reloc_sym if kernel supports it
We indicate support for accepting sym+offset with kretprobes through a
line in ftrace README. Parse the same to identify support and choose the
appropriate format for kprobe_events.
As an example, without this perf patch, but with the ftrace changes:
naveen@ubuntu:~/linux/tools/perf$ sudo cat /sys/kernel/debug/tracing/README | grep kretprobe
place (kretprobe): [<module>:]<symbol>[+<offset>]|<memaddr>
naveen@ubuntu:~/linux/tools/perf$
naveen@ubuntu:~/linux/tools/perf$ sudo ./perf probe -v do_open%return
probe-definition(0): do_open%return
symbol:do_open file:(null) line:0 offset:0 return:1 lazy:(null)
0 arguments
Looking at the vmlinux_path (8 entries long)
Using /boot/vmlinux for symbols
Open Debuginfo file: /boot/vmlinux
Try to find probe point from debuginfo.
Matched function: do_open [2d0c7d8]
Probe point found: do_open+0
Matched function: do_open [35d76b5]
found inline addr: 0xc0000000004ba984
Failed to find "do_open%return",
because do_open is an inlined function and has no return point.
An error occurred in debuginfo analysis (-22).
Trying to use symbols.
Opening /sys/kernel/debug/tracing//kprobe_events write=1
Writing event: r:probe/do_open do_open+0
Writing event: r:probe/do_open_1 do_open+0
Added new events:
probe:do_open (on do_open%return)
probe:do_open_1 (on do_open%return)
You can now use it in all perf tools, such as:
perf record -e probe:do_open_1 -aR sleep 1
naveen@ubuntu:~/linux/tools/perf$ sudo cat /sys/kernel/debug/kprobes/list
c000000000041370 k kretprobe_trampoline+0x0 [OPTIMIZED]
c0000000004433d0 r do_open+0x0 [DISABLED]
c0000000004433d0 r do_open+0x0 [DISABLED]
And after this patch (and the subsequent powerpc patch):
naveen@ubuntu:~/linux/tools/perf$ sudo ./perf probe -v do_open%return
probe-definition(0): do_open%return
symbol:do_open file:(null) line:0 offset:0 return:1 lazy:(null)
0 arguments
Looking at the vmlinux_path (8 entries long)
Using /boot/vmlinux for symbols
Open Debuginfo file: /boot/vmlinux
Try to find probe point from debuginfo.
Matched function: do_open [2d0c7d8]
Probe point found: do_open+0
Matched function: do_open [35d76b5]
found inline addr: 0xc0000000004ba984
Failed to find "do_open%return",
because do_open is an inlined function and has no return point.
An error occurred in debuginfo analysis (-22).
Trying to use symbols.
Opening /sys/kernel/debug/tracing//README write=0
Opening /sys/kernel/debug/tracing//kprobe_events write=1
Writing event: r:probe/do_open _text+4469712
Writing event: r:probe/do_open_1 _text+4956248
Added new events:
probe:do_open (on do_open%return)
probe:do_open_1 (on do_open%return)
You can now use it in all perf tools, such as:
perf record -e probe:do_open_1 -aR sleep 1
naveen@ubuntu:~/linux/tools/perf$ sudo cat /sys/kernel/debug/kprobes/list
c000000000041370 k kretprobe_trampoline+0x0 [OPTIMIZED]
c0000000004433d0 r do_open+0x0 [DISABLED]
c0000000004ba058 r do_open+0x8 [DISABLED]
Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: linuxppc-dev@lists.ozlabs.org
Link: http://lkml.kernel.org/r/496ef9f33c1ab16286ece9dd62aa672807aef91c.1488961018.git.naveen.n.rao@linux.vnet.ibm.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Diffstat (limited to 'tools/perf/util/probe-file.c')
-rw-r--r-- | tools/perf/util/probe-file.c | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/tools/perf/util/probe-file.c b/tools/perf/util/probe-file.c index 8a219cd831b7..1542cd0d6799 100644 --- a/tools/perf/util/probe-file.c +++ b/tools/perf/util/probe-file.c @@ -879,6 +879,7 @@ int probe_cache__show_all_caches(struct strfilter *filter) enum ftrace_readme { FTRACE_README_PROBE_TYPE_X = 0, + FTRACE_README_KRETPROBE_OFFSET, FTRACE_README_END, }; @@ -889,6 +890,7 @@ static struct { #define DEFINE_TYPE(idx, pat) \ [idx] = {.pattern = pat, .avail = false} DEFINE_TYPE(FTRACE_README_PROBE_TYPE_X, "*type: * x8/16/32/64,*"), + DEFINE_TYPE(FTRACE_README_KRETPROBE_OFFSET, "*place (kretprobe): *"), }; static bool scan_ftrace_readme(enum ftrace_readme type) @@ -939,3 +941,8 @@ bool probe_type_is_available(enum probe_type type) return true; } + +bool kretprobe_offset_is_supported(void) +{ + return scan_ftrace_readme(FTRACE_README_KRETPROBE_OFFSET); +} |