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perf tools: Add support for 32-bit compatibility VDSOs 

'perf record' post-processes the event stream  to create a list of
build-ids for object files for which sample events have been recorded.
That results in those object files being recorded in the build-id cache.

In the case of VDSO, perf tools reads it from memory and copies it into
a temporary file, which as decribed above, gets added to the build-id
cache.

Then when the perf.data file is processed by other tools, the build-id
of VDSO is listed in the perf.data file and the VDSO can be read from
the build-id cache.  In that case the name of the map, the short name of
the DSO, and the entry in the build-id cache are all "[vdso]".

However, in the 64-bit case, there also can be 32-bit compatibility
VDSOs.

A previous patch added programs "perf-read-vdso32" and "perf
read-vdsox32".

This patch uses those programs to read the correct VDSO for a thread and
create a temporary file just as for the 64-bit VDSO.

The map name and the entry in the build-id cache are still "[vdso]" but
the DSO short name becomes "[vdso32]" and "[vdsox32]" respectively.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/1414061124-26830-16-git-send-email-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
wifi-calibration
Adrian Hunter 2014-10-23 13:45:23 +03:00 committed by Arnaldo Carvalho de Melo
parent e477f3f01a
commit f6832e1720
2 changed files with 172 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

170
tools/perf/util/vdso.c
View File

@ -12,6 +12,7 @@
#include "util.h"
#include "symbol.h"
#include "machine.h"
#include "thread.h"
#include "linux/string.h"
#include "debug.h"
@ -28,10 +29,15 @@ struct vdso_file {
bool error;
char temp_file_name[sizeof(VDSO__TEMP_FILE_NAME)];
const char *dso_name;
const char *read_prog;
};
struct vdso_info {
struct vdso_file vdso;
#if BITS_PER_LONG == 64
struct vdso_file vdso32;
struct vdso_file vdsox32;
#endif
};
static struct vdso_info *vdso_info__new(void)
@ -41,6 +47,18 @@ static struct vdso_info *vdso_info__new(void)
.temp_file_name = VDSO__TEMP_FILE_NAME,
.dso_name = DSO__NAME_VDSO,
},
#if BITS_PER_LONG == 64
.vdso32 = {
.temp_file_name = VDSO__TEMP_FILE_NAME,
.dso_name = DSO__NAME_VDSO32,
.read_prog = "perf-read-vdso32",
},
.vdsox32 = {
.temp_file_name = VDSO__TEMP_FILE_NAME,
.dso_name = DSO__NAME_VDSOX32,
.read_prog = "perf-read-vdsox32",
},
#endif
};
return memdup(&vdso_info_init, sizeof(vdso_info_init));
@ -92,6 +110,12 @@ void vdso__exit(struct machine *machine)
if (vdso_info->vdso.found)
unlink(vdso_info->vdso.temp_file_name);
#if BITS_PER_LONG == 64
if (vdso_info->vdso32.found)
unlink(vdso_info->vdso32.temp_file_name);
if (vdso_info->vdsox32.found)
unlink(vdso_info->vdsox32.temp_file_name);
#endif
zfree(&machine->vdso_info);
}
@ -110,6 +134,143 @@ static struct dso *vdso__new(struct machine *machine, const char *short_name,
return dso;
}
#if BITS_PER_LONG == 64
static enum dso_type machine__thread_dso_type(struct machine *machine,
struct thread *thread)
{
enum dso_type dso_type = DSO__TYPE_UNKNOWN;
struct map *map;
struct dso *dso;
map = map_groups__first(thread->mg, MAP__FUNCTION);
for (; map ; map = map_groups__next(map)) {
dso = map->dso;
if (!dso || dso->long_name[0] != '/')
continue;
dso_type = dso__type(dso, machine);
if (dso_type != DSO__TYPE_UNKNOWN)
break;
}
return dso_type;
}
static int vdso__do_copy_compat(FILE *f, int fd)
{
char buf[4096];
size_t count;
while (1) {
count = fread(buf, 1, sizeof(buf), f);
if (ferror(f))
return -errno;
if (feof(f))
break;
if (count && writen(fd, buf, count) != (ssize_t)count)
return -errno;
}
return 0;
}
static int vdso__copy_compat(const char *prog, int fd)
{
FILE *f;
int err;
f = popen(prog, "r");
if (!f)
return -errno;
err = vdso__do_copy_compat(f, fd);
if (pclose(f) == -1)
return -errno;
return err;
}
static int vdso__create_compat_file(const char *prog, char *temp_name)
{
int fd, err;
fd = mkstemp(temp_name);
if (fd < 0)
return -errno;
err = vdso__copy_compat(prog, fd);
if (close(fd) == -1)
return -errno;
return err;
}
static const char *vdso__get_compat_file(struct vdso_file *vdso_file)
{
int err;
if (vdso_file->found)
return vdso_file->temp_file_name;
if (vdso_file->error)
return NULL;
err = vdso__create_compat_file(vdso_file->read_prog,
vdso_file->temp_file_name);
if (err) {
pr_err("%s failed, error %d\n", vdso_file->read_prog, err);
vdso_file->error = true;
return NULL;
}
vdso_file->found = true;
return vdso_file->temp_file_name;
}
static struct dso *vdso__findnew_compat(struct machine *machine,
struct vdso_file *vdso_file)
{
const char *file_name;
struct dso *dso;
dso = dsos__find(&machine->user_dsos, vdso_file->dso_name, true);
if (dso)
return dso;
file_name = vdso__get_compat_file(vdso_file);
if (!file_name)
return NULL;
return vdso__new(machine, vdso_file->dso_name, file_name);
}
static int vdso__dso_findnew_compat(struct machine *machine,
struct thread *thread,
struct vdso_info *vdso_info,
struct dso **dso)
{
enum dso_type dso_type;
dso_type = machine__thread_dso_type(machine, thread);
switch (dso_type) {
case DSO__TYPE_32BIT:
*dso = vdso__findnew_compat(machine, &vdso_info->vdso32);
return 1;
case DSO__TYPE_X32BIT:
*dso = vdso__findnew_compat(machine, &vdso_info->vdsox32);
return 1;
case DSO__TYPE_UNKNOWN:
case DSO__TYPE_64BIT:
default:
return 0;
}
}
#endif
struct dso *vdso__dso_findnew(struct machine *machine,
struct thread *thread __maybe_unused)
{
@ -123,6 +284,11 @@ struct dso *vdso__dso_findnew(struct machine *machine,
if (!vdso_info)
return NULL;
#if BITS_PER_LONG == 64
if (vdso__dso_findnew_compat(machine, thread, vdso_info, &dso))
return dso;
#endif
dso = dsos__find(&machine->user_dsos, DSO__NAME_VDSO, true);
if (!dso) {
char *file;
@ -139,5 +305,7 @@ struct dso *vdso__dso_findnew(struct machine *machine,
bool dso__is_vdso(struct dso *dso)
{
return !strcmp(dso->short_name, DSO__NAME_VDSO);
return !strcmp(dso->short_name, DSO__NAME_VDSO) ||
!strcmp(dso->short_name, DSO__NAME_VDSO32) ||
!strcmp(dso->short_name, DSO__NAME_VDSOX32);
}

4
tools/perf/util/vdso.h
View File

@ -7,7 +7,9 @@
#define VDSO__MAP_NAME "[vdso]"
#define DSO__NAME_VDSO "[vdso]"
#define DSO__NAME_VDSO "[vdso]"
#define DSO__NAME_VDSO32 "[vdso32]"
#define DSO__NAME_VDSOX32 "[vdsox32]"
static inline bool is_vdso_map(const char *filename)
{