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perf symbols: Filename__read_build_id should look at .notes section too

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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>
This commit is contained in:
Arnaldo Carvalho de Melo 2009-11-20 20:51:25 -02:00 committed by Ingo Molnar
parent 6671cb1674
commit fd7a346ea2
1 changed files with 38 additions and 9 deletions
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47
tools/perf/util/symbol.c
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@ -899,13 +899,19 @@ bool dsos__read_build_ids(void)
return have_build_id; 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 filename__read_build_id(const char *filename, void *bf, size_t size)
{ {
int fd, err = -1; int fd, err = -1;
GElf_Ehdr ehdr; GElf_Ehdr ehdr;
GElf_Shdr shdr; GElf_Shdr shdr;
Elf_Data *build_id_data; Elf_Data *data;
Elf_Scn *sec; Elf_Scn *sec;
void *ptr;
Elf *elf; Elf *elf;
if (size < BUILD_ID_SIZE) 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, sec = elf_section_by_name(elf, &ehdr, &shdr,
".note.gnu.build-id", NULL); ".note.gnu.build-id", NULL);
if (sec == NULL) if (sec == NULL) {
sec = elf_section_by_name(elf, &ehdr, &shdr,
".notes", NULL);
if (sec == NULL)
goto out_elf_end;
}
data = elf_getdata(sec, NULL);
if (data == NULL)
goto out_elf_end; goto out_elf_end;
build_id_data = elf_getdata(sec, NULL); ptr = data->d_buf;
if (build_id_data == NULL) while (ptr < (data->d_buf + data->d_size)) {
goto out_elf_end; GElf_Nhdr *nhdr = ptr;
memcpy(bf, build_id_data->d_buf + 16, BUILD_ID_SIZE); int namesz = NOTE_ALIGN(nhdr->n_namesz),
err = BUILD_ID_SIZE; 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: out_elf_end:
elf_end(elf); elf_end(elf);
out_close: 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)) if (read(fd, &nhdr, sizeof(nhdr)) != sizeof(nhdr))
break; break;
namesz = (nhdr.n_namesz + 3) & -4U; namesz = NOTE_ALIGN(nhdr.n_namesz);
descsz = (nhdr.n_descsz + 3) & -4U; descsz = NOTE_ALIGN(nhdr.n_descsz);
if (nhdr.n_type == NT_GNU_BUILD_ID && if (nhdr.n_type == NT_GNU_BUILD_ID &&
nhdr.n_namesz == sizeof("GNU")) { nhdr.n_namesz == sizeof("GNU")) {
if (read(fd, bf, namesz) != namesz) if (read(fd, bf, namesz) != namesz)