perf symbols: Record text offset in dso to calculate objdump address

Store DSO's .text offset into DSO, used for VDSOs and will also be used for
other needs, like handling kernel modules.

Signed-off-by: Wang Nan <wangnan0@huawei.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Cody P Schafer <dev@codyps.com>
Cc: He Kuang <hekuang@huawei.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kirill Smelkov <kirr@nexedi.com>
Cc: Li Zefan <lizefan@huawei.com>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: pi3orama@163.com
Link: http://lkml.kernel.org/r/1456479154-136027-2-git-send-email-wangnan0@huawei.com
[ Extracted from larger patch ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

2 files changed, 7 insertions, 6 deletions

diff --git a/tools/perf/util/dso.h b/tools/perf/util/dso.h
index 45ec4d0a50ed..ef3dbc989013 100644
--- a/tools/perf/util/dso.h
+++ b/tools/perf/util/dso.h
@@ -162,6 +162,7 @@ struct dso {
         u8               loaded;
         u8               rel;
         u8               build_id[BUILD_ID_SIZE];
+        u64              text_offset;
         const char       *short_name;
         const char       *long_name;
         u16              long_name_len;
diff --git a/tools/perf/util/symbol-elf.c b/tools/perf/util/symbol-elf.c
index b1dd68f358fc..bc229a74c6a9 100644
--- a/tools/perf/util/symbol-elf.c
+++ b/tools/perf/util/symbol-elf.c
@@ -793,6 +793,7 @@ int dso__load_sym(struct dso *dso, struct map *map,
         uint32_t idx;
         GElf_Ehdr ehdr;
         GElf_Shdr shdr;
+        GElf_Shdr tshdr;
         Elf_Data *syms, *opddata = NULL;
         GElf_Sym sym;
         Elf_Scn *sec, *sec_strndx;
@@ -832,6 +833,9 @@ int dso__load_sym(struct dso *dso, struct map *map,
         sec = syms_ss->symtab;
         shdr = syms_ss->symshdr;
 
+        if (elf_section_by_name(elf, &ehdr, &tshdr, ".text", NULL))
+                dso->text_offset = tshdr.sh_addr - tshdr.sh_offset;
+
         if (runtime_ss->opdsec)
                 opddata = elf_rawdata(runtime_ss->opdsec, NULL);
 
@@ -880,12 +884,8 @@ int dso__load_sym(struct dso *dso, struct map *map,
          * Handle any relocation of vdso necessary because older kernels
          * attempted to prelink vdso to its virtual address.
          */
-        if (dso__is_vdso(dso)) {
-                GElf_Shdr tshdr;
-
-                if (elf_section_by_name(elf, &ehdr, &tshdr, ".text", NULL))
-                        map->reloc = map->start - tshdr.sh_addr + tshdr.sh_offset;
-        }
+        if (dso__is_vdso(dso))
+                map->reloc = map->start - dso->text_offset;
 
         dso->adjust_symbols = runtime_ss->adjust_symbols || ref_reloc(kmap);
         /*