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authorArnaldo Carvalho de Melo <acme@redhat.com>2009-11-20 20:51:25 -0200
committerIngo Molnar <mingo@elte.hu>2009-11-21 14:11:32 +0100
commitfd7a346ea292074e9f6cdb5232a57c56bf98fdc9 (patch)
tree9f5154c912d274a4df4a913a8e9baaf3f652591e /tools/perf
parent6671cb1674e69e2aba3d610714bdd3e97a7b51ff (diff)
perf symbols: Filename__read_build_id should look at .notes section too
In the kernel we have more than one notes section, so the linker script combines all and puts them into a ".notes" combined section. So we need to look at both sections and also traverse them looking at multiple GElf_Nhdr entries till we find the one we want, with the build_id. Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Frédéric Weisbecker <fweisbec@gmail.com> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Paul Mackerras <paulus@samba.org> LKML-Reference: <1258757489-5978-2-git-send-email-acme@infradead.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'tools/perf')
-rw-r--r--tools/perf/util/symbol.c47
1 files changed, 38 insertions, 9 deletions
diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c
index 3b23c18cd36..d22030828c2 100644
--- a/tools/perf/util/symbol.c
+++ b/tools/perf/util/symbol.c
@@ -899,13 +899,19 @@ bool dsos__read_build_ids(void)
return have_build_id;
}
+/*
+ * Align offset to 4 bytes as needed for note name and descriptor data.
+ */
+#define NOTE_ALIGN(n) (((n) + 3) & -4U)
+
int filename__read_build_id(const char *filename, void *bf, size_t size)
{
int fd, err = -1;
GElf_Ehdr ehdr;
GElf_Shdr shdr;
- Elf_Data *build_id_data;
+ Elf_Data *data;
Elf_Scn *sec;
+ void *ptr;
Elf *elf;
if (size < BUILD_ID_SIZE)
@@ -928,14 +934,37 @@ int filename__read_build_id(const char *filename, void *bf, size_t size)
sec = elf_section_by_name(elf, &ehdr, &shdr,
".note.gnu.build-id", NULL);
- if (sec == NULL)
- goto out_elf_end;
+ if (sec == NULL) {
+ sec = elf_section_by_name(elf, &ehdr, &shdr,
+ ".notes", NULL);
+ if (sec == NULL)
+ goto out_elf_end;
+ }
- build_id_data = elf_getdata(sec, NULL);
- if (build_id_data == NULL)
+ data = elf_getdata(sec, NULL);
+ if (data == NULL)
goto out_elf_end;
- memcpy(bf, build_id_data->d_buf + 16, BUILD_ID_SIZE);
- err = BUILD_ID_SIZE;
+
+ ptr = data->d_buf;
+ while (ptr < (data->d_buf + data->d_size)) {
+ GElf_Nhdr *nhdr = ptr;
+ int namesz = NOTE_ALIGN(nhdr->n_namesz),
+ descsz = NOTE_ALIGN(nhdr->n_descsz);
+ const char *name;
+
+ ptr += sizeof(*nhdr);
+ name = ptr;
+ ptr += namesz;
+ if (nhdr->n_type == NT_GNU_BUILD_ID &&
+ nhdr->n_namesz == sizeof("GNU")) {
+ if (memcmp(name, "GNU", sizeof("GNU")) == 0) {
+ memcpy(bf, ptr, BUILD_ID_SIZE);
+ err = BUILD_ID_SIZE;
+ break;
+ }
+ }
+ ptr += descsz;
+ }
out_elf_end:
elf_end(elf);
out_close:
@@ -963,8 +992,8 @@ int sysfs__read_build_id(const char *filename, void *build_id, size_t size)
if (read(fd, &nhdr, sizeof(nhdr)) != sizeof(nhdr))
break;
- namesz = (nhdr.n_namesz + 3) & -4U;
- descsz = (nhdr.n_descsz + 3) & -4U;
+ namesz = NOTE_ALIGN(nhdr.n_namesz);
+ descsz = NOTE_ALIGN(nhdr.n_descsz);
if (nhdr.n_type == NT_GNU_BUILD_ID &&
nhdr.n_namesz == sizeof("GNU")) {
if (read(fd, bf, namesz) != namesz)