perf symbols: Record the build_ids of kernel modules too

[safe/jmp/linux-2.6] / tools / perf / util / symbol.c

diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c
index 946ec31..7b4cede 100644 (file)
--- a/tools/perf/util/symbol.c
+++ b/tools/perf/util/symbol.c
@@ -9,6 +9,7 @@
 #include <libelf.h>
 #include <gelf.h>
 #include <elf.h>
+#include <limits.h>
 #include <sys/utsname.h>
 
 enum dso_origin {
@@ -943,6 +944,50 @@ out:
        return err;
 }
 
+int sysfs__read_build_id(const char *filename, void *build_id, size_t size)
+{
+       int fd, err = -1;
+
+       if (size < BUILD_ID_SIZE)
+               goto out;
+
+       fd = open(filename, O_RDONLY);
+       if (fd < 0)
+               goto out;
+
+       while (1) {
+               char bf[BUFSIZ];
+               GElf_Nhdr nhdr;
+               int namesz, descsz;
+
+               if (read(fd, &nhdr, sizeof(nhdr)) != sizeof(nhdr))
+                       break;
+
+               namesz = (nhdr.n_namesz + 3) & -4U;
+               descsz = (nhdr.n_descsz + 3) & -4U;
+               if (nhdr.n_type == NT_GNU_BUILD_ID &&
+                   nhdr.n_namesz == sizeof("GNU")) {
+                       if (read(fd, bf, namesz) != namesz)
+                               break;
+                       if (memcmp(bf, "GNU", sizeof("GNU")) == 0) {
+                               if (read(fd, build_id,
+                                   BUILD_ID_SIZE) == BUILD_ID_SIZE) {
+                                       err = 0;
+                                       break;
+                               }
+                       } else if (read(fd, bf, descsz) != descsz)
+                               break;
+               } else {
+                       int n = namesz + descsz;
+                       if (read(fd, bf, n) != n)
+                               break;
+               }
+       }
+       close(fd);
+out:
+       return err;
+}
+
 char dso__symtab_origin(const struct dso *self)
 {
        static const char origin[] = {
@@ -1218,7 +1263,7 @@ static struct map *map__new2(u64 start, struct dso *dso)
        return self;
 }
 
-static int dsos__load_modules(void)
+int dsos__load_modules(void)
 {
        char *line = NULL;
        size_t n;
@@ -1268,6 +1313,12 @@ static int dsos__load_modules(void)
                        goto out_delete_line;
                }
 
+               snprintf(name, sizeof(name),
+                        "/sys/module/%s/notes/.note.gnu.build-id", line);
+               if (sysfs__read_build_id(name, dso->build_id,
+                                        sizeof(dso->build_id)) == 0)
+                       dso->has_build_id = true;
+
                dso->origin = DSO__ORIG_KMODULE;
                kernel_maps__insert(map);
                dsos__add(dso);