perf evsel: Introduce perf_evsel__open_strerror method

That consolidates the error messages in 'record', 'stat' and 'top', that
now get a consistent set of messages and allow other tools to use the
new method to report problems using whatever UI toolkit.

Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Namhyung Kim <namhyung@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/n/tip-1cudb7wl996kz7ilz83ctvhr@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

7 files changed, 68 insertions, 100 deletions

diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
index b8d0a39b484e..de60dd4ee5d3 100644
--- a/tools/perf/builtin-record.c
+++ b/tools/perf/builtin-record.c
@@ -224,7 +224,7 @@ static bool perf_evlist__equal(struct perf_evlist *evlist,
 
 static int perf_record__open(struct perf_record *rec)
 {
-        char msg[128];
+        char msg[512];
         struct perf_evsel *pos;
         struct perf_evlist *evlist = rec->evlist;
         struct perf_session *session = rec->session;
@@ -234,60 +234,18 @@ static int perf_record__open(struct perf_record *rec)
         perf_evlist__config(evlist, opts);
 
         list_for_each_entry(pos, &evlist->entries, node) {
-                struct perf_event_attr *attr = &pos->attr;
 try_again:
                 if (perf_evsel__open(pos, evlist->cpus, evlist->threads) < 0) {
-                        int err = errno;
-
-                        if (err == EPERM || err == EACCES) {
-                                ui__error_paranoid();
-                                rc = -err;
-                                goto out;
-                        } else if (err ==  ENODEV && opts->target.cpu_list) {
-                                pr_err("No such device - did you specify"
-                                       " an out-of-range profile CPU?\n");
-                                rc = -err;
-                                goto out;
-                        }
-
-                        if (perf_evsel__fallback(pos, err, msg, sizeof(msg))) {
+                        if (perf_evsel__fallback(pos, errno, msg, sizeof(msg))) {
                                 if (verbose)
                                         ui__warning("%s\n", msg);
                                 goto try_again;
                         }
 
-                        if (err == ENOENT) {
-                                ui__error("The %s event is not supported.\n",
-                                          perf_evsel__name(pos));
-                                rc = -err;
-                                goto out;
-                        } else if ((err == EOPNOTSUPP) && (attr->precise_ip)) {
-                                ui__error("\'precise\' request may not be supported. "
-                                          "Try removing 'p' modifier\n");
-                                rc = -err;
-                                goto out;
-                        }
-
-                        printf("\n");
-                        error("sys_perf_event_open() syscall returned with %d "
-                              "(%s) for event %s. /bin/dmesg may provide "
-                              "additional information.\n",
-                              err, strerror(err), perf_evsel__name(pos));
-
-#if defined(__i386__) || defined(__x86_64__)
-                        if (attr->type == PERF_TYPE_HARDWARE &&
-                            err == EOPNOTSUPP) {
-                                pr_err("No hardware sampling interrupt available."
-                                       " No APIC? If so then you can boot the kernel"
-                                       " with the \"lapic\" boot parameter to"
-                                       " force-enable it.\n");
-                                rc = -err;
-                                goto out;
-                        }
-#endif
-
-                        pr_err("No CONFIG_PERF_EVENTS=y kernel support configured?\n");
-                        rc = -err;
+                        rc = -errno;
+                        perf_evsel__open_strerror(pos, &opts->target,
+                                                  errno, msg, sizeof(msg));
+                        ui__error("%s\n", msg);
                         goto out;
                 }
         }
diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c
index ef067c193f93..1c2ac148a7d5 100644
--- a/tools/perf/builtin-stat.c
+++ b/tools/perf/builtin-stat.c
@@ -247,6 +247,7 @@ static int read_counter(struct perf_evsel *counter)
 
 static int __run_perf_stat(int argc __maybe_unused, const char **argv)
 {
+        char msg[512];
         unsigned long long t0, t1;
         struct perf_evsel *counter;
         int status = 0;
@@ -324,20 +325,13 @@ static int __run_perf_stat(int argc __maybe_unused, const char **argv)
                                 continue;
                         }
 
-                        if (errno == EPERM || errno == EACCES) {
-                                error("You may not have permission to collect %sstats.\n"
-                                      "\t Consider tweaking"
-                                      " /proc/sys/kernel/perf_event_paranoid or running as root.",
-                                      target.system_wide ? "system-wide " : "");
-                        } else {
-                                error("open_counter returned with %d (%s). "
-                                      "/bin/dmesg may provide additional information.\n",
-                                       errno, strerror(errno));
-                        }
+                        perf_evsel__open_strerror(counter, &target,
+                                                  errno, msg, sizeof(msg));
+                        ui__error("%s\n", msg);
+
                         if (child_pid != -1)
                                 kill(child_pid, SIGTERM);
 
-                        pr_err("Not all events could be opened.\n");
                         return -1;
                 }
                 counter->supported = true;
diff --git a/tools/perf/builtin-top.c b/tools/perf/builtin-top.c
index 8d41d0b58956..f5fd260f7b20 100644
--- a/tools/perf/builtin-top.c
+++ b/tools/perf/builtin-top.c
@@ -892,7 +892,7 @@ static void perf_top__mmap_read(struct perf_top *top)
 
 static void perf_top__start_counters(struct perf_top *top)
 {
-        char msg[128];
+        char msg[512];
         struct perf_evsel *counter;
         struct perf_evlist *evlist = top->evlist;
         struct perf_record_opts *opts = &top->record_opts;
@@ -900,42 +900,18 @@ static void perf_top__start_counters(struct perf_top *top)
         perf_evlist__config(evlist, opts);
 
         list_for_each_entry(counter, &evlist->entries, node) {
-                struct perf_event_attr *attr = &counter->attr;
 try_again:
                 if (perf_evsel__open(counter, top->evlist->cpus,
                                      top->evlist->threads) < 0) {
-                        int err = errno;
-
-                        if (err == EPERM || err == EACCES) {
-                                ui__error_paranoid();
-                                goto out_err;
-                        }
-
-                        if (perf_evsel__fallback(counter, err, msg, sizeof(msg))) {
+                        if (perf_evsel__fallback(counter, errno, msg, sizeof(msg))) {
                                 if (verbose)
                                         ui__warning("%s\n", msg);
                                 goto try_again;
                         }
 
-                        if (err == ENOENT) {
-                                ui__error("The %s event is not supported.\n",
-                                          perf_evsel__name(counter));
-                                goto out_err;
-                        } else if (err == EMFILE) {
-                                ui__error("Too many events are opened.\n"
-                                            "Try again after reducing the number of events\n");
-                                goto out_err;
-                        } else if ((err == EOPNOTSUPP) && (attr->precise_ip)) {
-                                ui__error("\'precise\' request may not be supported. "
-                                          "Try removing 'p' modifier\n");
-                                goto out_err;
-                        }
-
-                        ui__error("The sys_perf_event_open() syscall "
-                                    "returned with %d (%s).  /bin/dmesg "
-                                    "may provide additional information.\n"
-                                    "No CONFIG_PERF_EVENTS=y kernel support "
-                                    "configured?\n", err, strerror(err));
+                        perf_evsel__open_strerror(counter, &opts->target,
+                                                  errno, msg, sizeof(msg));
+                        ui__error("%s\n", msg);
                         goto out_err;
                 }
         }
diff --git a/tools/perf/ui/util.c b/tools/perf/ui/util.c
index 3014a7cd5271..e3e0a963d03a 100644
--- a/tools/perf/ui/util.c
+++ b/tools/perf/ui/util.c
@@ -52,17 +52,6 @@ int ui__warning(const char *format, ...)
         return ret;
 }
 
-int ui__error_paranoid(void)
-{
-        return ui__error("Permission error - are you root?\n"
-                    "Consider tweaking /proc/sys/kernel/perf_event_paranoid:\n"
-                    " -1 - Not paranoid at all\n"
-                    "  0 - Disallow raw tracepoint access for unpriv\n"
-                    "  1 - Disallow cpu events for unpriv\n"
-                    "  2 - Disallow kernel profiling for unpriv\n");
-}
-
-
 /**
  * perf_error__register - Register error logging functions
  * @eops: The pointer to error logging function struct
diff --git a/tools/perf/util/debug.h b/tools/perf/util/debug.h
index 6e2667fb8211..efbd98805ad0 100644
--- a/tools/perf/util/debug.h
+++ b/tools/perf/util/debug.h
@@ -16,6 +16,5 @@ void trace_event(union perf_event *event);
 
 int ui__error(const char *format, ...) __attribute__((format(printf, 1, 2)));
 int ui__warning(const char *format, ...) __attribute__((format(printf, 1, 2)));
-int ui__error_paranoid(void);
 
 #endif  /* __PERF_DEBUG_H */
diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c
index 0c88e5c12dab..e45332d08a58 100644
--- a/tools/perf/util/evsel.c
+++ b/tools/perf/util/evsel.c
@@ -1406,3 +1406,52 @@ bool perf_evsel__fallback(struct perf_evsel *evsel, int err,
 
         return false;
 }
+
+int perf_evsel__open_strerror(struct perf_evsel *evsel,
+                              struct perf_target *target,
+                              int err, char *msg, size_t size)
+{
+        switch (err) {
+        case EPERM:
+        case EACCES:
+                return scnprintf(msg, size, "%s",
+                 "You may not have permission to collect %sstats.\n"
+                 "Consider tweaking /proc/sys/kernel/perf_event_paranoid:\n"
+                 " -1 - Not paranoid at all\n"
+                 "  0 - Disallow raw tracepoint access for unpriv\n"
+                 "  1 - Disallow cpu events for unpriv\n"
+                 "  2 - Disallow kernel profiling for unpriv",
+                                 target->system_wide ? "system-wide " : "");
+        case ENOENT:
+                return scnprintf(msg, size, "The %s event is not supported.",
+                                 perf_evsel__name(evsel));
+        case EMFILE:
+                return scnprintf(msg, size, "%s",
+                         "Too many events are opened.\n"
+                         "Try again after reducing the number of events.");
+        case ENODEV:
+                if (target->cpu_list)
+                        return scnprintf(msg, size, "%s",
+         "No such device - did you specify an out-of-range profile CPU?\n");
+                break;
+        case EOPNOTSUPP:
+                if (evsel->attr.precise_ip)
+                        return scnprintf(msg, size, "%s",
+        "\'precise\' request may not be supported. Try removing 'p' modifier.");
+#if defined(__i386__) || defined(__x86_64__)
+                if (evsel->attr.type == PERF_TYPE_HARDWARE)
+                        return scnprintf(msg, size, "%s",
+        "No hardware sampling interrupt available.\n"
+        "No APIC? If so then you can boot the kernel with the \"lapic\" boot parameter to force-enable it.");
+#endif
+                break;
+        default:
+                break;
+        }
+
+        return scnprintf(msg, size,
+        "The sys_perf_event_open() syscall returned with %d (%s) for event (%s).  \n"
+        "/bin/dmesg may provide additional information.\n"
+        "No CONFIG_PERF_EVENTS=y kernel support configured?\n",
+                         err, strerror(err), perf_evsel__name(evsel));
+}
diff --git a/tools/perf/util/evsel.h b/tools/perf/util/evsel.h
index 26d8cfd86e0a..c68d1b82e843 100644
--- a/tools/perf/util/evsel.h
+++ b/tools/perf/util/evsel.h
@@ -254,4 +254,7 @@ int perf_evsel__fprintf(struct perf_evsel *evsel,
 
 bool perf_evsel__fallback(struct perf_evsel *evsel, int err,
                           char *msg, size_t msgsize);
+int perf_evsel__open_strerror(struct perf_evsel *evsel,
+                              struct perf_target *target,
+                              int err, char *msg, size_t size);
 #endif /* __PERF_EVSEL_H */