perf annotate: Show better message when no vmlinux is found

In both --tui and --stdio, in 'annotate', 'top', 'report' when trying to
annotate a kernel symbol having just access to a kallsyms file, that
doesn't have the DWARF info needed for annotation.

Suggested-by: Ingo Molnar <mingo@elte.hu>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Tom Zanussi <tzanussi@gmail.com>
LKML-Reference: <new-submission>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 13 insertions, 2 deletions

diff --git a/tools/perf/util/annotate.c b/tools/perf/util/annotate.c
index 70ec422ddb64..0d0830c98cd7 100644
--- a/tools/perf/util/annotate.c
+++ b/tools/perf/util/annotate.c
@@ -295,12 +295,23 @@ fallback:
         }
 
         if (dso->origin == DSO__ORIG_KERNEL) {
+                char bf[BUILD_ID_SIZE * 2 + 16] = " with build id ";
+                char *build_id_msg = NULL;
+
                 if (dso->annotate_warned)
                         goto out_free_filename;
+
+                if (dso->has_build_id) {
+                        build_id__sprintf(dso->build_id,
+                                          sizeof(dso->build_id), bf + 15);
+                        build_id_msg = bf;
+                }
                 err = -ENOENT;
                 dso->annotate_warned = 1;
-                pr_err("Can't annotate %s: No vmlinux file was found in the "
-                       "path\n", sym->name);
+                pr_err("Can't annotate %s: No vmlinux file%s was found in the "
+                       "path.\nPlease use 'perf buildid-cache -av vmlinux' or "
+                       "--vmlinux vmlinux.\n",
+                       sym->name, build_id_msg ?: "");
                 goto out_free_filename;
         }