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Commit 8f33f7de authored by Masami Hiramatsu's avatar Masami Hiramatsu Committed by Arnaldo Carvalho de Melo
Browse files

perf probe: Show appropriate symbol for ref_reloc_sym based kprobes 



Show appropriate symbol for ref_reloc_sym based kprobes instead of
refpoint+offset when perf-probe -l runs without debuginfo.

Without this change:
  # ./perf probe -l
    probe:t_show         (on _stext+889880 with m v)
    probe:t_show_1       (on _stext+928568 with m v t)
    probe:t_show_2       (on _stext+969512 with m v fmt)
    probe:t_show_3       (on _stext+1001416 with m v file)

With this change:
  # ./perf probe -l
    probe:t_show         (on t_show with m v)
    probe:t_show_1       (on t_show with m v t)
    probe:t_show_2       (on t_show with m v fmt)
    probe:t_show_3       (on t_show with m v file)

Changes from v2:
 - Check ref_reloc_sym to find correct unrelocated address.

Signed-off-by: default avatarMasami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: "David A. Long" <dave.long@linaro.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: yrl.pp-manager.tt@hitachi.com
Link: http://lkml.kernel.org/r/20140206053220.29635.81819.stgit@kbuild-fedora.yrl.intra.hitachi.co.jp


Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent f90acac7

tools/perf/util/probe-event.c

+55 −28
Original line number Diff line number Diff line
@@ -121,6 +121,42 @@ static struct symbol *__find_kernel_function_by_name(const char *name, 
						     NULL);

}



static struct symbol *__find_kernel_function(u64 addr, struct map **mapp)

{

	return machine__find_kernel_function(host_machine, addr, mapp, NULL);

}



static struct ref_reloc_sym *kernel_get_ref_reloc_sym(void)

{

	/* kmap->ref_reloc_sym should be set if host_machine is initialized */

	struct kmap *kmap;



	if (map__load(host_machine->vmlinux_maps[MAP__FUNCTION], NULL) < 0)

		return NULL;



	kmap = map__kmap(host_machine->vmlinux_maps[MAP__FUNCTION]);

	return kmap->ref_reloc_sym;

}



static u64 kernel_get_symbol_address_by_name(const char *name, bool reloc)

{

	struct ref_reloc_sym *reloc_sym;

	struct symbol *sym;

	struct map *map;



	/* ref_reloc_sym is just a label. Need a special fix*/

	reloc_sym = kernel_get_ref_reloc_sym();

	if (reloc_sym && strcmp(name, reloc_sym->name) == 0)

		return (reloc) ? reloc_sym->addr : reloc_sym->unrelocated_addr;

	else {

		sym = __find_kernel_function_by_name(name, &map);

		if (sym)

			return map->unmap_ip(map, sym->start) -

				(reloc) ? 0 : map->reloc;

	}

	return 0;

}



static struct map *kernel_get_module_map(const char *module)

{

	struct rb_node *nd;
@@ -216,12 +252,26 @@ static int convert_exec_to_group(const char *exec, char **result) 
static int convert_to_perf_probe_point(struct probe_trace_point *tp,

					struct perf_probe_point *pp)

{

	struct symbol *sym;

	struct map *map;

	u64 addr = kernel_get_symbol_address_by_name(tp->symbol, true);



	if (addr) {

		addr += tp->offset;

		sym = __find_kernel_function(addr, &map);

		if (!sym)

			goto failed;

		pp->function = strdup(sym->name);

		pp->offset = addr - map->unmap_ip(map, sym->start);

	} else {

failed:

		pp->function = strdup(tp->symbol);

		pp->offset = tp->offset;

	}



	if (pp->function == NULL)

		return -ENOMEM;



	pp->offset = tp->offset;

	pp->retprobe = tp->retprobe;



	return 0;
@@ -248,18 +298,6 @@ static struct debuginfo *open_debuginfo(const char *module) 
	return debuginfo__new(path);

}



static struct ref_reloc_sym *__kernel_get_ref_reloc_sym(void)

{

	/* kmap->ref_reloc_sym should be set if host_machine is initialized */

	struct kmap *kmap;



	if (map__load(host_machine->vmlinux_maps[MAP__FUNCTION], NULL) < 0)

		return NULL;



	kmap = map__kmap(host_machine->vmlinux_maps[MAP__FUNCTION]);

	return kmap->ref_reloc_sym;

}



/*

 * Convert trace point to probe point with debuginfo

 * Currently only handles kprobes.
@@ -267,24 +305,13 @@ static struct ref_reloc_sym *__kernel_get_ref_reloc_sym(void) 
static int kprobe_convert_to_perf_probe(struct probe_trace_point *tp,

					struct perf_probe_point *pp)

{

	struct symbol *sym;

	struct ref_reloc_sym *reloc_sym;

	struct map *map;

	u64 addr = 0;

	int ret = -ENOENT;

	struct debuginfo *dinfo;



	/* ref_reloc_sym is just a label. Need a special fix*/

	reloc_sym = __kernel_get_ref_reloc_sym();

	if (reloc_sym && strcmp(tp->symbol, reloc_sym->name) == 0)

		addr = reloc_sym->unrelocated_addr + tp->offset;

	else {

		sym = __find_kernel_function_by_name(tp->symbol, &map);

		if (sym)

			addr = map->unmap_ip(map, sym->start + tp->offset) -

				map->reloc;

	}

	addr = kernel_get_symbol_address_by_name(tp->symbol, false);

	if (addr) {

		addr += tp->offset;

		pr_debug("try to find %s+%ld@%" PRIx64 "\n", tp->symbol,

			 tp->offset, addr);
@@ -420,7 +447,7 @@ static int post_process_probe_trace_events(struct probe_trace_event *tevs, 
	if (module)

		return add_module_to_probe_trace_events(tevs, ntevs, module);



	reloc_sym = __kernel_get_ref_reloc_sym();

	reloc_sym = kernel_get_ref_reloc_sym();

	if (!reloc_sym) {

		pr_warning("Relocated base symbol is not found!\n");

		return -EINVAL;