Merge tag 'perf-core-for-mingo' of git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux into perf/core

Pull perf/core improvements and fixes from Arnaldo Carvalho de Melo:

User visible changes:

- Enhance the error reporting of tracepoint event parsing, e.g.:

    $ oldperf record -e sched:sched_switc usleep 1
    event syntax error: 'sched:sched_switc'
                         \___ unknown tracepoint
    Run 'perf list' for a list of valid events

  Now we get the much nicer:

    $ perf record -e sched:sched_switc ls
    event syntax error: 'sched:sched_switc'
                         \___ can't access trace events

    Error: No permissions to read /sys/kernel/debug/tracing/events/sched/sched_switc
    Hint:  Try 'sudo mount -o remount,mode=755 /sys/kernel/debug'

  And after we have those mount point permissions fixed:

    $ perf record -e sched:sched_switc ls
    event syntax error: 'sched:sched_switc'
                         \___ unknown tracepoint

    Error: File /sys/kernel/debug/tracing/events/sched/sched_switc not found.
    Hint:  Perhaps this kernel misses some CONFIG_ setting to enable this feature?.

  Now its just a matter of using what git uses to suggest alternatives when we
  make a typo, i.e. that it is just an 'h' missing :-)

  I.e. basically now the event parsing routing uses the strerror_open()
  routines introduced by and used in 'perf trace' work. (Jiri Olsa)

Infrastructure changes:

- Export init/exit_probe_symbol_maps() from 'perf probe' for use in eBPF.
  (Namhyung Kim)

- Free perf_probe_event in cleanup_perf_probe_events(). (Namhyung Kim)

- regs_query_register_offset() infrastructure + implementation for x86.
  First user will be the perf/eBPF code. (Wang Nan)

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>

1 files changed, 50 insertions, 16 deletions

diff --git a/tools/perf/util/parse-events.c b/tools/perf/util/parse-events.c
index 3840176642f8..d3fb90be6216 100644
--- a/tools/perf/util/parse-events.c
+++ b/tools/perf/util/parse-events.c
@@ -1,4 +1,5 @@
 #include <linux/hw_breakpoint.h>
+#include <linux/err.h>
 #include "util.h"
 #include "../perf.h"
 #include "evlist.h"
@@ -386,22 +387,52 @@ int parse_events_add_cache(struct list_head *list, int *idx,
         return add_event(list, idx, &attr, name, NULL);
 }
 
+static void tracepoint_error(struct parse_events_error *error, int err,
+                             char *sys, char *name)
+{
+        char help[BUFSIZ];
+
+        /*
+         * We get error directly from syscall errno ( > 0),
+         * or from encoded pointer's error ( < 0).
+         */
+        err = abs(err);
+
+        switch (err) {
+        case EACCES:
+                error->str = strdup("can't access trace events");
+                break;
+        case ENOENT:
+                error->str = strdup("unknown tracepoint");
+                break;
+        default:
+                error->str = strdup("failed to add tracepoint");
+                break;
+        }
+
+        tracing_path__strerror_open_tp(err, help, sizeof(help), sys, name);
+        error->help = strdup(help);
+}
+
 static int add_tracepoint(struct list_head *list, int *idx,
-                          char *sys_name, char *evt_name)
+                          char *sys_name, char *evt_name,
+                          struct parse_events_error *error __maybe_unused)
 {
         struct perf_evsel *evsel;
 
         evsel = perf_evsel__newtp_idx(sys_name, evt_name, (*idx)++);
-        if (!evsel)
-                return -ENOMEM;
+        if (IS_ERR(evsel)) {
+                tracepoint_error(error, PTR_ERR(evsel), sys_name, evt_name);
+                return PTR_ERR(evsel);
+        }
 
         list_add_tail(&evsel->node, list);
-
         return 0;
 }
 
 static int add_tracepoint_multi_event(struct list_head *list, int *idx,
-                                      char *sys_name, char *evt_name)
+                                      char *sys_name, char *evt_name,
+                                      struct parse_events_error *error)
 {
         char evt_path[MAXPATHLEN];
         struct dirent *evt_ent;
@@ -411,7 +442,7 @@ static int add_tracepoint_multi_event(struct list_head *list, int *idx,
         snprintf(evt_path, MAXPATHLEN, "%s/%s", tracing_events_path, sys_name);
         evt_dir = opendir(evt_path);
         if (!evt_dir) {
-                perror("Can't open event dir");
+                tracepoint_error(error, errno, sys_name, evt_name);
                 return -1;
         }
 
@@ -425,7 +456,7 @@ static int add_tracepoint_multi_event(struct list_head *list, int *idx,
                 if (!strglobmatch(evt_ent->d_name, evt_name))
                         continue;
 
-                ret = add_tracepoint(list, idx, sys_name, evt_ent->d_name);
+                ret = add_tracepoint(list, idx, sys_name, evt_ent->d_name, error);
         }
 
         closedir(evt_dir);
@@ -433,15 +464,17 @@ static int add_tracepoint_multi_event(struct list_head *list, int *idx,
 }
 
 static int add_tracepoint_event(struct list_head *list, int *idx,
-                                char *sys_name, char *evt_name)
+                                char *sys_name, char *evt_name,
+                                struct parse_events_error *error)
 {
         return strpbrk(evt_name, "*?") ?
-               add_tracepoint_multi_event(list, idx, sys_name, evt_name) :
-               add_tracepoint(list, idx, sys_name, evt_name);
+               add_tracepoint_multi_event(list, idx, sys_name, evt_name, error) :
+               add_tracepoint(list, idx, sys_name, evt_name, error);
 }
 
 static int add_tracepoint_multi_sys(struct list_head *list, int *idx,
-                                    char *sys_name, char *evt_name)
+                                    char *sys_name, char *evt_name,
+                                    struct parse_events_error *error)
 {
         struct dirent *events_ent;
         DIR *events_dir;
@@ -449,7 +482,7 @@ static int add_tracepoint_multi_sys(struct list_head *list, int *idx,
 
         events_dir = opendir(tracing_events_path);
         if (!events_dir) {
-                perror("Can't open event dir");
+                tracepoint_error(error, errno, sys_name, evt_name);
                 return -1;
         }
 
@@ -465,7 +498,7 @@ static int add_tracepoint_multi_sys(struct list_head *list, int *idx,
                         continue;
 
                 ret = add_tracepoint_event(list, idx, events_ent->d_name,
-                                           evt_name);
+                                           evt_name, error);
         }
 
         closedir(events_dir);
@@ -473,12 +506,13 @@ static int add_tracepoint_multi_sys(struct list_head *list, int *idx,
 }
 
 int parse_events_add_tracepoint(struct list_head *list, int *idx,
-                                char *sys, char *event)
+                                char *sys, char *event,
+                                struct parse_events_error *error)
 {
         if (strpbrk(sys, "*?"))
-                return add_tracepoint_multi_sys(list, idx, sys, event);
+                return add_tracepoint_multi_sys(list, idx, sys, event, error);
         else
-                return add_tracepoint_event(list, idx, sys, event);
+                return add_tracepoint_event(list, idx, sys, event, error);
 }
 
 static int