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Commit f6832e17 authored by Adrian Hunter's avatar Adrian Hunter Committed by Arnaldo Carvalho de Melo
Browse files

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: default avatarAdrian 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: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent e477f3f0

tools/perf/util/vdso.c

+169 −1
Original line number Diff line number Diff line
@@ -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);

}

tools/perf/util/vdso.h

+3 −1
Original line number Diff line number Diff line
@@ -8,6 +8,8 @@ 
#define VDSO__MAP_NAME "[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)

{