9 files changed, 129 insertions, 38 deletions

diff --git a/tools/perf/util/event.c b/tools/perf/util/event.c
index 1fc1c2f04772..b0f3ca850e9e 100644
--- a/tools/perf/util/event.c
+++ b/tools/perf/util/event.c
@@ -470,23 +470,32 @@ static int find_symbol_cb(void *arg, const char *name, char type,
         return 1;
 }
 
+u64 kallsyms__get_function_start(const char *kallsyms_filename,
+                                 const char *symbol_name)
+{
+        struct process_symbol_args args = { .name = symbol_name, };
+
+        if (kallsyms__parse(kallsyms_filename, &args, find_symbol_cb) <= 0)
+                return 0;
+
+        return args.start;
+}
+
 int perf_event__synthesize_kernel_mmap(struct perf_tool *tool,
                                        perf_event__handler_t process,
-                                       struct machine *machine,
-                                       const char *symbol_name)
+                                       struct machine *machine)
 {
         size_t size;
-        const char *filename, *mmap_name;
-        char path[PATH_MAX];
+        const char *mmap_name;
         char name_buff[PATH_MAX];
         struct map *map;
+        struct kmap *kmap;
         int err;
         /*
          * We should get this from /sys/kernel/sections/.text, but till that is
          * available use this, and after it is use this as a fallback for older
          * kernels.
          */
-        struct process_symbol_args args = { .name = symbol_name, };
         union perf_event *event = zalloc((sizeof(event->mmap) +
                                           machine->id_hdr_size));
         if (event == NULL) {
@@ -502,30 +511,19 @@ int perf_event__synthesize_kernel_mmap(struct perf_tool *tool,
                  * see kernel/perf_event.c __perf_event_mmap
                  */
                 event->header.misc = PERF_RECORD_MISC_KERNEL;
-                filename = "/proc/kallsyms";
         } else {
                 event->header.misc = PERF_RECORD_MISC_GUEST_KERNEL;
-                if (machine__is_default_guest(machine))
-                        filename = (char *) symbol_conf.default_guest_kallsyms;
-                else {
-                        sprintf(path, "%s/proc/kallsyms", machine->root_dir);
-                        filename = path;
-                }
-        }
-
-        if (kallsyms__parse(filename, &args, find_symbol_cb) <= 0) {
-                free(event);
-                return -ENOENT;
         }
 
         map = machine->vmlinux_maps[MAP__FUNCTION];
+        kmap = map__kmap(map);
         size = snprintf(event->mmap.filename, sizeof(event->mmap.filename),
-                        "%s%s", mmap_name, symbol_name) + 1;
+                        "%s%s", mmap_name, kmap->ref_reloc_sym->name) + 1;
         size = PERF_ALIGN(size, sizeof(u64));
         event->mmap.header.type = PERF_RECORD_MMAP;
         event->mmap.header.size = (sizeof(event->mmap) -
                         (sizeof(event->mmap.filename) - size) + machine->id_hdr_size);
-        event->mmap.pgoff = args.start;
+        event->mmap.pgoff = kmap->ref_reloc_sym->addr;
         event->mmap.start = map->start;
         event->mmap.len   = map->end - event->mmap.start;
         event->mmap.pid   = machine->pid;
diff --git a/tools/perf/util/event.h b/tools/perf/util/event.h
index faf6e219be21..851fa06f4a42 100644
--- a/tools/perf/util/event.h
+++ b/tools/perf/util/event.h
@@ -214,8 +214,7 @@ int perf_event__synthesize_threads(struct perf_tool *tool,
                                    struct machine *machine, bool mmap_data);
 int perf_event__synthesize_kernel_mmap(struct perf_tool *tool,
                                        perf_event__handler_t process,
-                                       struct machine *machine,
-                                       const char *symbol_name);
+                                       struct machine *machine);
 
 int perf_event__synthesize_modules(struct perf_tool *tool,
                                    perf_event__handler_t process,
@@ -279,4 +278,7 @@ size_t perf_event__fprintf_mmap2(union perf_event *event, FILE *fp);
 size_t perf_event__fprintf_task(union perf_event *event, FILE *fp);
 size_t perf_event__fprintf(union perf_event *event, FILE *fp);
 
+u64 kallsyms__get_function_start(const char *kallsyms_filename,
+                                 const char *symbol_name);
+
 #endif /* __PERF_RECORD_H */
diff --git a/tools/perf/util/include/asm/hash.h b/tools/perf/util/include/asm/hash.h
new file mode 100644
index 000000000000..d82b170bb216
--- /dev/null
+++ b/tools/perf/util/include/asm/hash.h
@@ -0,0 +1,6 @@
+#ifndef __ASM_GENERIC_HASH_H
+#define __ASM_GENERIC_HASH_H
+
+/* Stub */
+
+#endif /* __ASM_GENERIC_HASH_H */
diff --git a/tools/perf/util/machine.c b/tools/perf/util/machine.c
index ded74590b92f..c872991e0f65 100644
--- a/tools/perf/util/machine.c
+++ b/tools/perf/util/machine.c
@@ -496,19 +496,22 @@ static int symbol__in_kernel(void *arg, const char *name,
         return 1;
 }
 
+static void machine__get_kallsyms_filename(struct machine *machine, char *buf,
+                                           size_t bufsz)
+{
+        if (machine__is_default_guest(machine))
+                scnprintf(buf, bufsz, "%s", symbol_conf.default_guest_kallsyms);
+        else
+                scnprintf(buf, bufsz, "%s/proc/kallsyms", machine->root_dir);
+}
+
 /* Figure out the start address of kernel map from /proc/kallsyms */
 static u64 machine__get_kernel_start_addr(struct machine *machine)
 {
-        const char *filename;
-        char path[PATH_MAX];
+        char filename[PATH_MAX];
         struct process_args args;
 
-        if (machine__is_default_guest(machine))
-                filename = (char *)symbol_conf.default_guest_kallsyms;
-        else {
-                sprintf(path, "%s/proc/kallsyms", machine->root_dir);
-                filename = path;
-        }
+        machine__get_kallsyms_filename(machine, filename, PATH_MAX);
 
         if (symbol__restricted_filename(filename, "/proc/kallsyms"))
                 return 0;
@@ -829,9 +832,25 @@ static int machine__create_modules(struct machine *machine)
         return 0;
 }
 
+const char *ref_reloc_sym_names[] = {"_text", "_stext", NULL};
+
 int machine__create_kernel_maps(struct machine *machine)
 {
         struct dso *kernel = machine__get_kernel(machine);
+        char filename[PATH_MAX];
+        const char *name;
+        u64 addr = 0;
+        int i;
+
+        machine__get_kallsyms_filename(machine, filename, PATH_MAX);
+
+        for (i = 0; (name = ref_reloc_sym_names[i]) != NULL; i++) {
+                addr = kallsyms__get_function_start(filename, name);
+                if (addr)
+                        break;
+        }
+        if (!addr)
+                return -1;
 
         if (kernel == NULL ||
             __machine__create_kernel_maps(machine, kernel) < 0)
@@ -850,6 +869,13 @@ int machine__create_kernel_maps(struct machine *machine)
          * Now that we have all the maps created, just set the ->end of them:
          */
         map_groups__fixup_end(&machine->kmaps);
+
+        if (maps__set_kallsyms_ref_reloc_sym(machine->vmlinux_maps, name,
+                                             addr)) {
+                machine__destroy_kernel_maps(machine);
+                return -1;
+        }
+
         return 0;
 }
 
diff --git a/tools/perf/util/machine.h b/tools/perf/util/machine.h
index 477133015440..f77e91e483dc 100644
--- a/tools/perf/util/machine.h
+++ b/tools/perf/util/machine.h
@@ -18,6 +18,8 @@ union perf_event;
 #define HOST_KERNEL_ID                  (-1)
 #define DEFAULT_GUEST_KERNEL_ID         (0)
 
+extern const char *ref_reloc_sym_names[];
+
 struct machine {
         struct rb_node    rb_node;
         pid_t             pid;
diff --git a/tools/perf/util/map.c b/tools/perf/util/map.c
index 3b97513f0e77..39cd2d0faff6 100644
--- a/tools/perf/util/map.c
+++ b/tools/perf/util/map.c
@@ -39,6 +39,7 @@ void map__init(struct map *map, enum map_type type,
         map->start    = start;
         map->end      = end;
         map->pgoff    = pgoff;
+        map->reloc    = 0;
         map->dso      = dso;
         map->map_ip   = map__map_ip;
         map->unmap_ip = map__unmap_ip;
@@ -288,7 +289,7 @@ u64 map__rip_2objdump(struct map *map, u64 rip)
         if (map->dso->rel)
                 return rip - map->pgoff;
 
-        return map->unmap_ip(map, rip);
+        return map->unmap_ip(map, rip) - map->reloc;
 }
 
 /**
@@ -311,7 +312,7 @@ u64 map__objdump_2mem(struct map *map, u64 ip)
         if (map->dso->rel)
                 return map->unmap_ip(map, ip + map->pgoff);
 
-        return ip;
+        return ip + map->reloc;
 }
 
 void map_groups__init(struct map_groups *mg)
diff --git a/tools/perf/util/map.h b/tools/perf/util/map.h
index 18068c6b71c1..257e513205ce 100644
--- a/tools/perf/util/map.h
+++ b/tools/perf/util/map.h
@@ -36,6 +36,7 @@ struct map {
         bool                    erange_warned;
         u32                     priv;
         u64                     pgoff;
+        u64                     reloc;
         u32                     maj, min; /* only valid for MMAP2 record */
         u64                     ino;      /* only valid for MMAP2 record */
         u64                     ino_generation;/* only valid for MMAP2 record */
diff --git a/tools/perf/util/symbol-elf.c b/tools/perf/util/symbol-elf.c
index 759456728703..3e9f336740fa 100644
--- a/tools/perf/util/symbol-elf.c
+++ b/tools/perf/util/symbol-elf.c
@@ -751,6 +751,8 @@ int dso__load_sym(struct dso *dso, struct map *map,
                         if (strcmp(elf_name, kmap->ref_reloc_sym->name))
                                 continue;
                         kmap->ref_reloc_sym->unrelocated_addr = sym.st_value;
+                        map->reloc = kmap->ref_reloc_sym->addr -
+                                     kmap->ref_reloc_sym->unrelocated_addr;
                         break;
                 }
         }
@@ -922,6 +924,7 @@ int dso__load_sym(struct dso *dso, struct map *map,
                                   (u64)shdr.sh_offset);
                         sym.st_value -= shdr.sh_addr - shdr.sh_offset;
                 }
+new_symbol:
                 /*
                  * We need to figure out if the object was created from C++ sources
                  * DWARF DW_compile_unit has this, but we don't always have access
@@ -933,7 +936,6 @@ int dso__load_sym(struct dso *dso, struct map *map,
                         if (demangled != NULL)
                                 elf_name = demangled;
                 }
-new_symbol:
                 f = symbol__new(sym.st_value, sym.st_size,
                                 GELF_ST_BIND(sym.st_info), elf_name);
                 free(demangled);
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;
                 }