1 files changed, 59 insertions, 6 deletions

diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c
index 39ce9adbaaf0..a9d758a3b371 100644
--- a/tools/perf/util/symbol.c
+++ b/tools/perf/util/symbol.c
@@ -627,7 +627,7 @@ static int dso__split_kallsyms_for_kcore(struct dso *dso, struct map *map,
  * kernel range is broken in several maps, named [kernel].N, as we don't have
  * the original ELF section names vmlinux have.
  */
-static int dso__split_kallsyms(struct dso *dso, struct map *map,
+static int dso__split_kallsyms(struct dso *dso, struct map *map, u64 delta,
                                symbol_filter_t filter)
 {
         struct map_groups *kmaps = map__kmap(map)->kmaps;
@@ -692,6 +692,12 @@ static int dso__split_kallsyms(struct dso *dso, struct map *map,
                         char dso_name[PATH_MAX];
                         struct dso *ndso;
 
+                        if (delta) {
+                                /* Kernel was relocated at boot time */
+                                pos->start -= delta;
+                                pos->end -= delta;
+                        }
+
                         if (count == 0) {
                                 curr_map = map;
                                 goto filter_symbol;
@@ -721,6 +727,10 @@ static int dso__split_kallsyms(struct dso *dso, struct map *map,
                         curr_map->map_ip = curr_map->unmap_ip = identity__map_ip;
                         map_groups__insert(kmaps, curr_map);
                         ++kernel_range;
+                } else if (delta) {
+                        /* Kernel was relocated at boot time */
+                        pos->start -= delta;
+                        pos->end -= delta;
                 }
 filter_symbol:
                 if (filter && filter(curr_map, pos)) {
@@ -976,6 +986,23 @@ static int validate_kcore_modules(const char *kallsyms_filename,
         return 0;
 }
 
+static int validate_kcore_addresses(const char *kallsyms_filename,
+                                    struct map *map)
+{
+        struct kmap *kmap = map__kmap(map);
+
+        if (kmap->ref_reloc_sym && kmap->ref_reloc_sym->name) {
+                u64 start;
+
+                start = kallsyms__get_function_start(kallsyms_filename,
+                                                     kmap->ref_reloc_sym->name);
+                if (start != kmap->ref_reloc_sym->addr)
+                        return -EINVAL;
+        }
+
+        return validate_kcore_modules(kallsyms_filename, map);
+}
+
 struct kcore_mapfn_data {
         struct dso *dso;
         enum map_type type;
@@ -1019,8 +1046,8 @@ static int dso__load_kcore(struct dso *dso, struct map *map,
                                              kallsyms_filename))
                 return -EINVAL;
 
-        /* All modules must be present at their original addresses */
-        if (validate_kcore_modules(kallsyms_filename, map))
+        /* Modules and kernel must be present at their original addresses */
+        if (validate_kcore_addresses(kallsyms_filename, map))
                 return -EINVAL;
 
         md.dso = dso;
@@ -1113,15 +1140,41 @@ out_err:
         return -EINVAL;
 }
 
+/*
+ * If the kernel is relocated at boot time, kallsyms won't match.  Compute the
+ * delta based on the relocation reference symbol.
+ */
+static int kallsyms__delta(struct map *map, const char *filename, u64 *delta)
+{
+        struct kmap *kmap = map__kmap(map);
+        u64 addr;
+
+        if (!kmap->ref_reloc_sym || !kmap->ref_reloc_sym->name)
+                return 0;
+
+        addr = kallsyms__get_function_start(filename,
+                                            kmap->ref_reloc_sym->name);
+        if (!addr)
+                return -1;
+
+        *delta = addr - kmap->ref_reloc_sym->addr;
+        return 0;
+}
+
 int dso__load_kallsyms(struct dso *dso, const char *filename,
                        struct map *map, symbol_filter_t filter)
 {
+        u64 delta = 0;
+
         if (symbol__restricted_filename(filename, "/proc/kallsyms"))
                 return -1;
 
         if (dso__load_all_kallsyms(dso, filename, map) < 0)
                 return -1;
 
+        if (kallsyms__delta(map, filename, &delta))
+                return -1;
+
         symbols__fixup_duplicate(&dso->symbols[map->type]);
         symbols__fixup_end(&dso->symbols[map->type]);
 
@@ -1133,7 +1186,7 @@ int dso__load_kallsyms(struct dso *dso, const char *filename,
         if (!dso__load_kcore(dso, map, filename))
                 return dso__split_kallsyms_for_kcore(dso, map, filter);
         else
-                return dso__split_kallsyms(dso, map, filter);
+                return dso__split_kallsyms(dso, map, delta, filter);
 }
 
 static int dso__load_perf_map(struct dso *dso, struct map *map,
@@ -1424,7 +1477,7 @@ static int find_matching_kcore(struct map *map, char *dir, size_t dir_sz)
                         continue;
                 scnprintf(kallsyms_filename, sizeof(kallsyms_filename),
                           "%s/%s/kallsyms", dir, dent->d_name);
-                if (!validate_kcore_modules(kallsyms_filename, map)) {
+                if (!validate_kcore_addresses(kallsyms_filename, map)) {
                         strlcpy(dir, kallsyms_filename, dir_sz);
                         ret = 0;
                         break;
@@ -1479,7 +1532,7 @@ static char *dso__find_kallsyms(struct dso *dso, struct map *map)
                 if (fd != -1) {
                         close(fd);
                         /* If module maps match go with /proc/kallsyms */
-                        if (!validate_kcore_modules("/proc/kallsyms", map))
+                        if (!validate_kcore_addresses("/proc/kallsyms", map))
                                 goto proc_kallsyms;
                 }