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Commit 9e201442 authored by Arnaldo Carvalho de Melo's avatar Arnaldo Carvalho de Melo Committed by Ingo Molnar
Browse files

perf symbols: Cache /proc/kallsyms files by build-id 



So that when we don't have a vmlinux handy we can store the
kallsyms for later use by 'perf report'.

Signed-off-by: default avatarArnaldo 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: <1263501006-14185-3-git-send-email-acme@infradead.org>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 8d0591f6

tools/perf/util/event.c

+1 −1
Original line number Diff line number Diff line
@@ -245,7 +245,7 @@ int event__synthesize_kernel_mmap(event__handler_t process, 
	 */

	struct process_symbol_args args = { .name = symbol_name, };



	if (kallsyms__parse(&args, find_symbol_cb) <= 0)

	if (kallsyms__parse("/proc/kallsyms", &args, find_symbol_cb) <= 0)

		return -ENOENT;



	size = snprintf(ev.mmap.filename, sizeof(ev.mmap.filename),

tools/perf/util/header.c

+11 −4
Original line number Diff line number Diff line
@@ -237,11 +237,13 @@ static int dso__cache_build_id(struct dso *self, const char *debugdir) 
	char *filename = malloc(size),

	     *linkname = malloc(size), *targetname, *sbuild_id;

	int len, err = -1;

	bool is_kallsyms = self->kernel && self->long_name[0] != '/';



	if (filename == NULL || linkname == NULL)

		goto out_free;



	len = snprintf(filename, size, "%s%s", debugdir, self->long_name);

	len = snprintf(filename, size, "%s%s%s",

		       debugdir, is_kallsyms ? "/" : "", self->long_name);

	if (mkdir_p(filename, 0755))

		goto out_free;
@@ -249,9 +251,14 @@ static int dso__cache_build_id(struct dso *self, const char *debugdir) 
	sbuild_id = filename + len;

	build_id__sprintf(self->build_id, sizeof(self->build_id), sbuild_id);



	if (access(filename, F_OK) && link(self->long_name, filename) &&

	if (access(filename, F_OK)) {

		if (is_kallsyms) {

			 if (copyfile("/proc/kallsyms", filename))

				goto out_free;

		} else if (link(self->long_name, filename) &&

			   copyfile(self->long_name, filename))

			goto out_free;

	}



	len = snprintf(linkname, size, "%s/.build-id/%.2s",

		       debugdir, sbuild_id);

tools/perf/util/symbol.c

+35 −13
Original line number Diff line number Diff line
@@ -383,13 +383,14 @@ size_t dso__fprintf(struct dso *self, enum map_type type, FILE *fp) 
	return ret;

}



int kallsyms__parse(void *arg, int (*process_symbol)(void *arg, const char *name,

int kallsyms__parse(const char *filename, void *arg,

		    int (*process_symbol)(void *arg, const char *name,

						     char type, u64 start))

{

	char *line = NULL;

	size_t n;

	int err = 0;

	FILE *file = fopen("/proc/kallsyms", "r");

	FILE *file = fopen(filename, "r");



	if (file == NULL)

		goto out_failure;
@@ -466,10 +467,11 @@ static int map__process_kallsym_symbol(void *arg, const char *name, 
 * so that we can in the next step set the symbol ->end address and then

 * call kernel_maps__split_kallsyms.

 */

static int dso__load_all_kallsyms(struct dso *self, struct map *map)

static int dso__load_all_kallsyms(struct dso *self, const char *filename,

				  struct map *map)

{

	struct process_kallsyms_args args = { .map = map, .dso = self, };

	return kallsyms__parse(&args, map__process_kallsym_symbol);

	return kallsyms__parse(filename, &args, map__process_kallsym_symbol);

}



/*
@@ -556,10 +558,10 @@ discard_symbol: rb_erase(&pos->rb_node, root); 
}





static int dso__load_kallsyms(struct dso *self, struct map *map,

static int dso__load_kallsyms(struct dso *self, const char *filename, struct map *map,

			      struct perf_session *session, symbol_filter_t filter)

{

	if (dso__load_all_kallsyms(self, map) < 0)

	if (dso__load_all_kallsyms(self, filename, map) < 0)

		return -1;



	symbols__fixup_end(&self->symbols[map->type]);
@@ -1580,7 +1582,8 @@ static int dso__load_kernel_sym(struct dso *self, struct map *map, 
				struct perf_session *session, symbol_filter_t filter)

{

	int err;

	bool is_kallsyms;

	const char *kallsyms_filename = NULL;

	char *kallsyms_allocated_filename = NULL;



	if (vmlinux_path != NULL) {

		int i;
@@ -1606,19 +1609,37 @@ static int dso__load_kernel_sym(struct dso *self, struct map *map, 
	 */

	if (self->has_build_id) {

		u8 kallsyms_build_id[BUILD_ID_SIZE];

		char sbuild_id[BUILD_ID_SIZE * 2 + 1];



		if (sysfs__read_build_id("/sys/kernel/notes", kallsyms_build_id,

					 sizeof(kallsyms_build_id)) == 0) {

			is_kallsyms = dso__build_id_equal(self, kallsyms_build_id);

			if (is_kallsyms)

			if (dso__build_id_equal(self, kallsyms_build_id)) {

				kallsyms_filename = "/proc/kallsyms";

				goto do_kallsyms;

			}

		}



		build_id__sprintf(self->build_id, sizeof(self->build_id),

				  sbuild_id);



		if (asprintf(&kallsyms_allocated_filename,

			     "%s/.debug/[kernel.kallsyms]/%s",

			     getenv("HOME"), sbuild_id) != -1) {

			if (access(kallsyms_filename, F_OK)) {

				kallsyms_filename = kallsyms_allocated_filename;

				goto do_kallsyms;

			}

			free(kallsyms_allocated_filename);

			kallsyms_allocated_filename = NULL;

		}



		goto do_vmlinux;

	}



	is_kallsyms = self->long_name[0] == '[';

	if (is_kallsyms)

	if (self->long_name[0] == '[') {

		kallsyms_filename = "/proc/kallsyms";

		goto do_kallsyms;

	}



do_vmlinux:

	err = dso__load_vmlinux(self, map, session, self->long_name, filter);
@@ -1629,9 +1650,10 @@ static int dso__load_kernel_sym(struct dso *self, struct map *map, 
		pr_info("The file %s cannot be used, "

			"trying to use /proc/kallsyms...", self->long_name);

do_kallsyms:

		err = dso__load_kallsyms(self, map, session, filter);

		if (err > 0 && !is_kallsyms)

		err = dso__load_kallsyms(self, kallsyms_filename, map, session, filter);

		if (err > 0 && kallsyms_filename == NULL)

                        dso__set_long_name(self, strdup("[kernel.kallsyms]"));

		free(kallsyms_allocated_filename);

	}



	if (err > 0) {

tools/perf/util/symbol.h

+3 −2
Original line number Diff line number Diff line
@@ -144,7 +144,8 @@ int filename__read_build_id(const char *filename, void *bf, size_t size); 
int sysfs__read_build_id(const char *filename, void *bf, size_t size);

bool dsos__read_build_ids(void);

int build_id__sprintf(u8 *self, int len, char *bf);

int kallsyms__parse(void *arg, int (*process_symbol)(void *arg, const char *name,

int kallsyms__parse(const char *filename, void *arg,

		    int (*process_symbol)(void *arg, const char *name,

					  char type, u64 start));



int symbol__init(void);

tools/perf/util/util.c

+30 −0
Original line number Diff line number Diff line
@@ -32,6 +32,33 @@ int mkdir_p(char *path, mode_t mode) 
	return (stat(path, &st) && mkdir(path, mode)) ? -1 : 0;

}



static int slow_copyfile(const char *from, const char *to)

{

	int err = 0;

	char *line = NULL;

	size_t n;

	FILE *from_fp = fopen(from, "r"), *to_fp;



	if (from_fp == NULL)

		goto out;



	to_fp = fopen(to, "w");

	if (to_fp == NULL)

		goto out_fclose_from;



	while (getline(&line, &n, from_fp) > 0)

		if (fputs(line, to_fp) == EOF)

			goto out_fclose_to;

	err = 0;

out_fclose_to:

	fclose(to_fp);

	free(line);

out_fclose_from:

	fclose(from_fp);

out:

	return err;

}



int copyfile(const char *from, const char *to)

{

	int fromfd, tofd;
@@ -42,6 +69,9 @@ int copyfile(const char *from, const char *to) 
	if (stat(from, &st))

		goto out;



	if (st.st_size == 0) /* /proc? do it slowly... */

		return slow_copyfile(from, to);



	fromfd = open(from, O_RDONLY);

	if (fromfd < 0)

		goto out;