4 files changed, 62 insertions, 3 deletions

diff --git a/tools/perf/Documentation/perf-probe.txt b/tools/perf/Documentation/perf-probe.txt
index 94a258c96a44..ea531d9d975c 100644
--- a/tools/perf/Documentation/perf-probe.txt
+++ b/tools/perf/Documentation/perf-probe.txt
@@ -31,6 +31,10 @@ OPTIONS
 --vmlinux=PATH::
         Specify vmlinux path which has debuginfo (Dwarf binary).
 
+-s::
+--source=PATH::
+        Specify path to kernel source.
+
 -v::
 --verbose::
         Be more verbose (show parsed arguments, etc).
diff --git a/tools/perf/builtin-probe.c b/tools/perf/builtin-probe.c
index e4a4da32a568..54551867e7e0 100644
--- a/tools/perf/builtin-probe.c
+++ b/tools/perf/builtin-probe.c
@@ -182,6 +182,8 @@ static const struct option options[] = {
                      "Show source code lines.", opt_show_lines),
         OPT_STRING('k', "vmlinux", &symbol_conf.vmlinux_name,
                    "file", "vmlinux pathname"),
+        OPT_STRING('s', "source", &symbol_conf.source_prefix,
+                   "directory", "path to kernel source"),
 #endif
         OPT__DRY_RUN(&probe_event_dry_run),
         OPT_INTEGER('\0', "max-probes", &params.max_probe_points,
diff --git a/tools/perf/util/probe-finder.c b/tools/perf/util/probe-finder.c
index d964cb199c67..baf665383498 100644
--- a/tools/perf/util/probe-finder.c
+++ b/tools/perf/util/probe-finder.c
@@ -37,6 +37,7 @@
 #include "event.h"
 #include "debug.h"
 #include "util.h"
+#include "symbol.h"
 #include "probe-finder.h"
 
 /* Kprobe tracer basic type is up to u64 */
@@ -57,6 +58,55 @@ static int strtailcmp(const char *s1, const char *s2)
         return 0;
 }
 
+/*
+ * Find a src file from a DWARF tag path. Prepend optional source path prefix
+ * and chop off leading directories that do not exist. Result is passed back as
+ * a newly allocated path on success.
+ * Return 0 if file was found and readable, -errno otherwise.
+ */
+static int get_real_path(const char *raw_path, char **new_path)
+{
+        if (!symbol_conf.source_prefix) {
+                if (access(raw_path, R_OK) == 0) {
+                        *new_path = strdup(raw_path);
+                        return 0;
+                } else
+                        return -errno;
+        }
+
+        *new_path = malloc((strlen(symbol_conf.source_prefix) +
+                            strlen(raw_path) + 2));
+        if (!*new_path)
+                return -ENOMEM;
+
+        for (;;) {
+                sprintf(*new_path, "%s/%s", symbol_conf.source_prefix,
+                        raw_path);
+
+                if (access(*new_path, R_OK) == 0)
+                        return 0;
+
+                switch (errno) {
+                case ENAMETOOLONG:
+                case ENOENT:
+                case EROFS:
+                case EFAULT:
+                        raw_path = strchr(++raw_path, '/');
+                        if (!raw_path) {
+                                free(*new_path);
+                                *new_path = NULL;
+                                return -ENOENT;
+                        }
+                        continue;
+
+                default:
+                        free(*new_path);
+                        *new_path = NULL;
+                        return -errno;
+                }
+        }
+}
+
 /* Line number list operations */
 
 /* Add a line to line number list */
@@ -1096,11 +1146,13 @@ end:
 static int line_range_add_line(const char *src, unsigned int lineno,
                                struct line_range *lr)
 {
+        int ret;
+
         /* Copy real path */
         if (!lr->path) {
-                lr->path = strdup(src);
-                if (lr->path == NULL)
-                        return -ENOMEM;
+                ret = get_real_path(src, &lr->path);
+                if (ret != 0)
+                        return ret;
         }
         return line_list__add_line(&lr->line_list, lineno);
 }
diff --git a/tools/perf/util/symbol.h b/tools/perf/util/symbol.h
index 10b7ff859ce0..80e569bbdecc 100644
--- a/tools/perf/util/symbol.h
+++ b/tools/perf/util/symbol.h
@@ -71,6 +71,7 @@ struct symbol_conf {
                         full_paths,
                         show_cpu_utilization;
         const char      *vmlinux_name,
+                        *source_prefix,
                         *field_sep;
         const char      *default_guest_vmlinux_name,
                         *default_guest_kallsyms,