perf probe: Accept %sdt and %cached event name

To improve usability, support %[PROVIDER:]SDTEVENT format to add new
probes on SDT and cached events.

e.g.
  ----
  # perf probe -x /lib/libc-2.17.so  %lll_lock_wait_private
  Added new event:
    sdt_libc:lll_lock_wait_private (on %lll_lock_wait_private in /usr/lib/libc-2.17.so)

  You can now use it in all perf tools, such as:

          perf record -e sdt_libc:lll_lock_wait_private -aR sleep 1

  # perf probe -l | more
    sdt_libc:lll_lock_wait_private (on __lll_lock_wait_private+21 in /usr/lib/libc-2.17.so)
  ----

Note that this is not only for SDT events, but also normal
events with event-name.

e.g. define "myevent" on cache (-n doesn't add the real probe)
  ----
  # perf probe -x ./perf --cache -n --add 'myevent=dso__load $params'
  ----
  Reuse the "myevent" from cache as below.
  ----
  # perf probe -x ./perf %myevent
  ----

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com>
Cc: Brendan Gregg <brendan.d.gregg@gmail.com>
Cc: Hemant Kumar <hemant@linux.vnet.ibm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/146831788372.17065.3645054540325909346.stgit@devbox
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

4 files changed, 76 insertions, 25 deletions

diff --git a/tools/perf/Documentation/perf-probe.txt b/tools/perf/Documentation/perf-probe.txt
index 7a258e953252..39e387042098 100644
--- a/tools/perf/Documentation/perf-probe.txt
+++ b/tools/perf/Documentation/perf-probe.txt
@@ -151,6 +151,8 @@ Probe points are defined by following syntax.
     3) Define event based on source file with lazy pattern
      [[GROUP:]EVENT=]SRC;PTN [ARG ...]
 
+    4) Pre-defined SDT events or cached event with name
+     %[PROVIDER:]SDTEVENT
 
 'EVENT' specifies the name of new event, if omitted, it will be set the name of the probed function. You can also specify a group name by 'GROUP', if omitted, set 'probe' is used for kprobe and 'probe_<bin>' is used for uprobe.
 Note that using existing group name can conflict with other events. Especially, using the group name reserved for kernel modules can hide embedded events in the
@@ -158,6 +160,11 @@ modules.
 'FUNC' specifies a probed function name, and it may have one of the following options; '+OFFS' is the offset from function entry address in bytes, ':RLN' is the relative-line number from function entry line, and '%return' means that it probes function return. And ';PTN' means lazy matching pattern (see LAZY MATCHING). Note that ';PTN' must be the end of the probe point definition.  In addition, '@SRC' specifies a source file which has that function.
 It is also possible to specify a probe point by the source line number or lazy matching by using 'SRC:ALN' or 'SRC;PTN' syntax, where 'SRC' is the source file path, ':ALN' is the line number and ';PTN' is the lazy matching pattern.
 'ARG' specifies the arguments of this probe point, (see PROBE ARGUMENT).
+'SDTEVENT' and 'PROVIDER' is the pre-defined event name which is defined by user SDT (Statically Defined Tracing) or the pre-cached probes with event name.
+Note that before using the SDT event, the target binary (on which SDT events are defined) must be scanned by linkperf:perf-buildid-cache[1] to make SDT events as cached events.
+
+For details of the SDT, see below.
+https://sourceware.org/gdb/onlinedocs/gdb/Static-Probe-Points.html
 
 PROBE ARGUMENT
 --------------
@@ -237,4 +244,4 @@ Add probes at malloc() function on libc
 
 SEE ALSO
 --------
-linkperf:perf-trace[1], linkperf:perf-record[1]
+linkperf:perf-trace[1], linkperf:perf-record[1], linkperf:perf-buildid-cache[1]
diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
index fef9768df429..85f25d41cf8d 100644
--- a/tools/perf/util/probe-event.c
+++ b/tools/perf/util/probe-event.c
@@ -1197,6 +1197,34 @@ err:
         return err;
 }
 
+static int parse_perf_probe_event_name(char **arg, struct perf_probe_event *pev)
+{
+        char *ptr;
+
+        ptr = strchr(*arg, ':');
+        if (ptr) {
+                *ptr = '\0';
+                if (!is_c_func_name(*arg))
+                        goto ng_name;
+                pev->group = strdup(*arg);
+                if (!pev->group)
+                        return -ENOMEM;
+                *arg = ptr + 1;
+        } else
+                pev->group = NULL;
+        if (!is_c_func_name(*arg)) {
+ng_name:
+                semantic_error("%s is bad for event name -it must "
+                               "follow C symbol-naming rule.\n", *arg);
+                return -EINVAL;
+        }
+        pev->event = strdup(*arg);
+        if (pev->event == NULL)
+                return -ENOMEM;
+
+        return 0;
+}
+
 /* Parse probepoint definition. */
 static int parse_perf_probe_point(char *arg, struct perf_probe_event *pev)
 {
@@ -1204,38 +1232,43 @@ static int parse_perf_probe_point(char *arg, struct perf_probe_event *pev)
         char *ptr, *tmp;
         char c, nc = 0;
         bool file_spec = false;
+        int ret;
+
         /*
          * <Syntax>
          * perf probe [GRP:][EVENT=]SRC[:LN|;PTN]
          * perf probe [GRP:][EVENT=]FUNC[@SRC][+OFFS|%return|:LN|;PAT]
+         * perf probe %[GRP:]SDT_EVENT
          */
         if (!arg)
                 return -EINVAL;
 
+        if (arg[0] == '%') {
+                pev->sdt = true;
+                arg++;
+        }
+
         ptr = strpbrk(arg, ";=@+%");
-        if (ptr && *ptr == '=') {       /* Event name */
-                *ptr = '\0';
-                tmp = ptr + 1;
-                ptr = strchr(arg, ':');
+        if (pev->sdt) {
                 if (ptr) {
-                        *ptr = '\0';
-                        if (!is_c_func_name(arg))
-                                goto not_fname;
-                        pev->group = strdup(arg);
-                        if (!pev->group)
-                                return -ENOMEM;
-                        arg = ptr + 1;
-                } else
-                        pev->group = NULL;
-                if (!is_c_func_name(arg)) {
-not_fname:
-                        semantic_error("%s is bad for event name -it must "
-                                       "follow C symbol-naming rule.\n", arg);
+                        semantic_error("%s must contain only an SDT event name.\n", arg);
                         return -EINVAL;
                 }
-                pev->event = strdup(arg);
-                if (pev->event == NULL)
-                        return -ENOMEM;
+                ret = parse_perf_probe_event_name(&arg, pev);
+                if (ret == 0) {
+                        if (asprintf(&pev->point.function, "%%%s", pev->event) < 0)
+                                ret = -errno;
+                }
+                return ret;
+        }
+
+        if (ptr && *ptr == '=') {       /* Event name */
+                *ptr = '\0';
+                tmp = ptr + 1;
+                ret = parse_perf_probe_event_name(&arg, pev);
+                if (ret < 0)
+                        return ret;
+
                 arg = tmp;
         }
 
@@ -2876,7 +2909,8 @@ static int find_probe_trace_events_from_cache(struct perf_probe_event *pev,
 
         entry = probe_cache__find(cache, pev);
         if (!entry) {
-                ret = 0;
+                /* SDT must be in the cache */
+                ret = pev->sdt ? -ENOENT : 0;
                 goto out;
         }
 
@@ -2915,7 +2949,7 @@ static int convert_to_probe_trace_events(struct perf_probe_event *pev,
 {
         int ret;
 
-        if (!pev->group) {
+        if (!pev->group && !pev->sdt) {
                 /* Set group name if not given */
                 if (!pev->uprobes) {
                         pev->group = strdup(PERFPROBE_GROUP);
@@ -2934,8 +2968,8 @@ static int convert_to_probe_trace_events(struct perf_probe_event *pev,
 
         /* At first, we need to lookup cache entry */
         ret = find_probe_trace_events_from_cache(pev, tevs);
-        if (ret > 0)
-                return ret;     /* Found in probe cache */
+        if (ret > 0 || pev->sdt)        /* SDT can be found only in the cache */
+                return ret == 0 ? -ENOENT : ret; /* Found in probe cache */
 
         if (arch__prefers_symtab() && !perf_probe_event_need_dwarf(pev)) {
                 ret = find_probe_trace_events_from_map(pev, tevs);
diff --git a/tools/perf/util/probe-event.h b/tools/perf/util/probe-event.h
index 432b690d3f17..e18ea9fe6385 100644
--- a/tools/perf/util/probe-event.h
+++ b/tools/perf/util/probe-event.h
@@ -85,6 +85,7 @@ struct perf_probe_event {
         char                    *group; /* Group name */
         struct perf_probe_point point;  /* Probe point */
         int                     nargs;  /* Number of arguments */
+        bool                    sdt;    /* SDT/cached event flag */
         bool                    uprobes;        /* Uprobe event flag */
         char                    *target;        /* Target binary */
         struct perf_probe_arg   *args;  /* Arguments */
diff --git a/tools/perf/util/probe-file.c b/tools/perf/util/probe-file.c
index e705a742ee1e..fc16b172579f 100644
--- a/tools/perf/util/probe-file.c
+++ b/tools/perf/util/probe-file.c
@@ -547,6 +547,15 @@ probe_cache__find(struct probe_cache *pcache, struct perf_probe_event *pev)
                 return NULL;
 
         list_for_each_entry(entry, &pcache->entries, node) {
+                if (pev->sdt) {
+                        if (entry->pev.event &&
+                            streql(entry->pev.event, pev->event) &&
+                            (!pev->group ||
+                             streql(entry->pev.group, pev->group)))
+                                goto found;
+
+                        continue;
+                }
                 /* Hit if same event name or same command-string */
                 if ((pev->event &&
                      (streql(entry->pev.group, pev->group) &&