9 files changed, 81 insertions, 19 deletions

diff --git a/tools/perf/Documentation/perf-diff.txt b/tools/perf/Documentation/perf-diff.txt
index 6a9ec2b35310..74d7481ed7a6 100644
--- a/tools/perf/Documentation/perf-diff.txt
+++ b/tools/perf/Documentation/perf-diff.txt
@@ -66,6 +66,8 @@ OPTIONS
 --force::
        Don't complain, do it.
 
+--symfs=<directory>::
+        Look for files with symbols relative to this directory.
 
 SEE ALSO
 --------
diff --git a/tools/perf/Documentation/perf-report.txt b/tools/perf/Documentation/perf-report.txt
index fefea77ec6e9..8ba03d6e5398 100644
--- a/tools/perf/Documentation/perf-report.txt
+++ b/tools/perf/Documentation/perf-report.txt
@@ -116,6 +116,9 @@ OPTIONS
 --force::
         Don't complain, do it.
 
+--symfs=<directory>::
+        Look for files with symbols relative to this directory.
+
 SEE ALSO
 --------
 linkperf:perf-stat[1]
diff --git a/tools/perf/Documentation/perf-timechart.txt b/tools/perf/Documentation/perf-timechart.txt
index 4b1788355eca..d7b79e2ba2ad 100644
--- a/tools/perf/Documentation/perf-timechart.txt
+++ b/tools/perf/Documentation/perf-timechart.txt
@@ -38,6 +38,8 @@ OPTIONS
 --process::
         Select the processes to display, by name or PID
 
+--symfs=<directory>::
+        Look for files with symbols relative to this directory.
 
 SEE ALSO
 --------
diff --git a/tools/perf/builtin-diff.c b/tools/perf/builtin-diff.c
index 97846dcafc63..3153e492dbcc 100644
--- a/tools/perf/builtin-diff.c
+++ b/tools/perf/builtin-diff.c
@@ -194,6 +194,8 @@ static const struct option options[] = {
         OPT_STRING('t', "field-separator", &symbol_conf.field_sep, "separator",
                    "separator for columns, no spaces will be added between "
                    "columns '.' is reserved."),
+        OPT_STRING(0, "symfs", &symbol_conf.symfs, "directory",
+                    "Look for files with symbols relative to this directory"),
         OPT_END()
 };
 
diff --git a/tools/perf/builtin-report.c b/tools/perf/builtin-report.c
index 4af7ce6e1555..75183a4518e6 100644
--- a/tools/perf/builtin-report.c
+++ b/tools/perf/builtin-report.c
@@ -483,6 +483,8 @@ static const struct option options[] = {
                    "columns '.' is reserved."),
         OPT_BOOLEAN('U', "hide-unresolved", &hide_unresolved,
                     "Only display entries resolved to a symbol"),
+        OPT_STRING(0, "symfs", &symbol_conf.symfs, "directory",
+                    "Look for files with symbols relative to this directory"),
         OPT_END()
 };
 
diff --git a/tools/perf/builtin-timechart.c b/tools/perf/builtin-timechart.c
index 459b5e3db267..d75084bccdb7 100644
--- a/tools/perf/builtin-timechart.c
+++ b/tools/perf/builtin-timechart.c
@@ -1022,6 +1022,8 @@ static const struct option options[] = {
         OPT_CALLBACK('p', "process", NULL, "process",
                       "process selector. Pass a pid or process name.",
                        parse_process),
+        OPT_STRING(0, "symfs", &symbol_conf.symfs, "directory",
+                    "Look for files with symbols relative to this directory"),
         OPT_END()
 };
 
diff --git a/tools/perf/util/hist.c b/tools/perf/util/hist.c
index a3b84160c42e..d5036700a435 100644
--- a/tools/perf/util/hist.c
+++ b/tools/perf/util/hist.c
@@ -1092,6 +1092,12 @@ int hist_entry__annotate(struct hist_entry *self, struct list_head *head,
         FILE *file;
         int err = 0;
         u64 len;
+        char symfs_filename[PATH_MAX];
+
+        if (filename) {
+                snprintf(symfs_filename, sizeof(symfs_filename), "%s%s",
+                         symbol_conf.symfs, filename);
+        }
 
         if (filename == NULL) {
                 if (dso->has_build_id) {
@@ -1100,9 +1106,9 @@ int hist_entry__annotate(struct hist_entry *self, struct list_head *head,
                         return -ENOMEM;
                 }
                 goto fallback;
-        } else if (readlink(filename, command, sizeof(command)) < 0 ||
+        } else if (readlink(symfs_filename, command, sizeof(command)) < 0 ||
                    strstr(command, "[kernel.kallsyms]") ||
-                   access(filename, R_OK)) {
+                   access(symfs_filename, R_OK)) {
                 free(filename);
 fallback:
                 /*
@@ -1111,6 +1117,8 @@ fallback:
                  * DSO is the same as when 'perf record' ran.
                  */
                 filename = dso->long_name;
+                snprintf(symfs_filename, sizeof(symfs_filename), "%s%s",
+                         symbol_conf.symfs, filename);
                 free_filename = false;
         }
 
@@ -1137,7 +1145,7 @@ fallback:
                  "objdump --start-address=0x%016Lx --stop-address=0x%016Lx -dS -C %s|grep -v %s|expand",
                  map__rip_2objdump(map, sym->start),
                  map__rip_2objdump(map, sym->end),
-                 filename, filename);
+                 symfs_filename, filename);
 
         pr_debug("Executing: %s\n", command);
 
diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c
index ceefa6568def..561db6361f57 100644
--- a/tools/perf/util/symbol.c
+++ b/tools/perf/util/symbol.c
@@ -41,6 +41,7 @@ struct symbol_conf symbol_conf = {
         .exclude_other    = true,
         .use_modules      = true,
         .try_vmlinux_path = true,
+        .symfs            = "",
 };
 
 int dso__name_len(const struct dso *self)
@@ -839,8 +840,11 @@ static int dso__synthesize_plt_symbols(struct  dso *self, struct map *map,
         char sympltname[1024];
         Elf *elf;
         int nr = 0, symidx, fd, err = 0;
+        char name[PATH_MAX];
 
-        fd = open(self->long_name, O_RDONLY);
+        snprintf(name, sizeof(name), "%s%s",
+                 symbol_conf.symfs, self->long_name);
+        fd = open(name, O_RDONLY);
         if (fd < 0)
                 goto out;
 
@@ -1452,16 +1456,19 @@ int dso__load(struct dso *self, struct map *map, symbol_filter_t filter)
              self->origin++) {
                 switch (self->origin) {
                 case DSO__ORIG_BUILD_ID_CACHE:
-                        if (dso__build_id_filename(self, name, size) == NULL)
+                        /* skip the locally configured cache if a symfs is given */
+                        if (symbol_conf.symfs[0] ||
+                            (dso__build_id_filename(self, name, size) == NULL)) {
                                 continue;
+                        }
                         break;
                 case DSO__ORIG_FEDORA:
-                        snprintf(name, size, "/usr/lib/debug%s.debug",
-                                 self->long_name);
+                        snprintf(name, size, "%s/usr/lib/debug%s.debug",
+                                 symbol_conf.symfs, self->long_name);
                         break;
                 case DSO__ORIG_UBUNTU:
-                        snprintf(name, size, "/usr/lib/debug%s",
-                                 self->long_name);
+                        snprintf(name, size, "%s/usr/lib/debug%s",
+                                 symbol_conf.symfs, self->long_name);
                         break;
                 case DSO__ORIG_BUILDID: {
                         char build_id_hex[BUILD_ID_SIZE * 2 + 1];
@@ -1473,19 +1480,26 @@ int dso__load(struct dso *self, struct map *map, symbol_filter_t filter)
                                           sizeof(self->build_id),
                                           build_id_hex);
                         snprintf(name, size,
-                                 "/usr/lib/debug/.build-id/%.2s/%s.debug",
-                                 build_id_hex, build_id_hex + 2);
+                                 "%s/usr/lib/debug/.build-id/%.2s/%s.debug",
+                                 symbol_conf.symfs, build_id_hex, build_id_hex + 2);
                         }
                         break;
                 case DSO__ORIG_DSO:
-                        snprintf(name, size, "%s", self->long_name);
+                        snprintf(name, size, "%s%s",
+                             symbol_conf.symfs, self->long_name);
                         break;
                 case DSO__ORIG_GUEST_KMODULE:
                         if (map->groups && map->groups->machine)
                                 root_dir = map->groups->machine->root_dir;
                         else
                                 root_dir = "";
-                        snprintf(name, size, "%s%s", root_dir, self->long_name);
+                        snprintf(name, size, "%s%s%s", symbol_conf.symfs,
+                                 root_dir, self->long_name);
+                        break;
+
+                case DSO__ORIG_KMODULE:
+                        snprintf(name, size, "%s%s", symbol_conf.symfs,
+                                 self->long_name);
                         break;
 
                 default:
@@ -1784,17 +1798,20 @@ static int dso__load_vmlinux(struct dso *self, struct map *map,
                              const char *vmlinux, symbol_filter_t filter)
 {
         int err = -1, fd;
+        char symfs_vmlinux[PATH_MAX];
 
-        fd = open(vmlinux, O_RDONLY);
+        snprintf(symfs_vmlinux, sizeof(symfs_vmlinux), "%s/%s",
+                 symbol_conf.symfs, vmlinux);
+        fd = open(symfs_vmlinux, O_RDONLY);
         if (fd < 0)
                 return -1;
 
         dso__set_loaded(self, map->type);
-        err = dso__load_sym(self, map, vmlinux, fd, filter, 0, 0);
+        err = dso__load_sym(self, map, symfs_vmlinux, fd, filter, 0, 0);
         close(fd);
 
         if (err > 0)
-                pr_debug("Using %s for symbols\n", vmlinux);
+                pr_debug("Using %s for symbols\n", symfs_vmlinux);
 
         return err;
 }
@@ -1872,6 +1889,10 @@ static int dso__load_kernel_sym(struct dso *self, struct map *map,
                         goto out_fixup;
         }
 
+        /* do not try local files if a symfs was given */
+        if (symbol_conf.symfs[0] != 0)
+                return -1;
+
         /*
          * Say the kernel DSO was created when processing the build-id header table,
          * we have a build-id, so check if it is the same as the running kernel,
@@ -2262,9 +2283,6 @@ static int vmlinux_path__init(void)
         struct utsname uts;
         char bf[PATH_MAX];
 
-        if (uname(&uts) < 0)
-                return -1;
-
         vmlinux_path = malloc(sizeof(char *) * 5);
         if (vmlinux_path == NULL)
                 return -1;
@@ -2277,6 +2295,14 @@ static int vmlinux_path__init(void)
         if (vmlinux_path[vmlinux_path__nr_entries] == NULL)
                 goto out_fail;
         ++vmlinux_path__nr_entries;
+
+        /* only try running kernel version if no symfs was given */
+        if (symbol_conf.symfs[0] != 0)
+                return 0;
+
+        if (uname(&uts) < 0)
+                return -1;
+
         snprintf(bf, sizeof(bf), "/boot/vmlinux-%s", uts.release);
         vmlinux_path[vmlinux_path__nr_entries] = strdup(bf);
         if (vmlinux_path[vmlinux_path__nr_entries] == NULL)
@@ -2336,6 +2362,8 @@ static int setup_list(struct strlist **list, const char *list_str,
 
 int symbol__init(void)
 {
+        const char *symfs;
+
         if (symbol_conf.initialized)
                 return 0;
 
@@ -2364,6 +2392,18 @@ int symbol__init(void)
                        symbol_conf.sym_list_str, "symbol") < 0)
                 goto out_free_comm_list;
 
+        /*
+         * A path to symbols of "/" is identical to ""
+         * reset here for simplicity.
+         */
+        symfs = realpath(symbol_conf.symfs, NULL);
+        if (symfs == NULL)
+                symfs = symbol_conf.symfs;
+        if (strcmp(symfs, "/") == 0)
+                symbol_conf.symfs = "";
+        if (symfs != symbol_conf.symfs)
+                free((void *)symfs);
+
         symbol_conf.initialized = true;
         return 0;
 
diff --git a/tools/perf/util/symbol.h b/tools/perf/util/symbol.h
index 12defbe18c13..bcd2f986927e 100644
--- a/tools/perf/util/symbol.h
+++ b/tools/perf/util/symbol.h
@@ -86,6 +86,7 @@ struct symbol_conf {
        struct strlist   *dso_list,
                         *comm_list,
                         *sym_list;
+        const char      *symfs;
 };
 
 extern struct symbol_conf symbol_conf;