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Commit f1dfa0b1 authored by Arnaldo Carvalho de Melo's avatar Arnaldo Carvalho de Melo Committed by Ingo Molnar
Browse files

perf symbols: Add support for 'variable' symtabs 



Example:

{
	u64 addr = strtoull(sym_filter, NULL, 16);
	struct map *map = map_groups__find(kmaps, MAP__VARIABLE, addr);

	if (map == NULL)
		pr_err("couldn't find map!\n");
	else {
		struct symbol *sym = map__find_symbol(map, addr, NULL);
		if (sym == NULL)
			pr_err("couldn't find addr!\n");
		else
			pr_info("addr %#Lx is in %s global var\n", addr, sym->name);
	}
	exit(0);
}

Added just after symbol__init() call in 'perf top', then:

{
        u64 addr = strtoull(sym_filter, NULL, 16);
        struct map *map = map_groups__find(kmaps, MAP__VARIABLE, addr);

        if (map == NULL)
                pr_err("couldn't find map!\n");
        else {
                struct symbol *sym = map__find_symbol(map, addr, NULL);
                if (sym == NULL)
                        pr_err("couldn't find addr!\n");
                else
                        pr_info("addr %#Lx is in %s global var\n", addr, sym->name);
        }
        exit(0);
}

[root@doppio linux-2.6-tip]# grep ' [dD] ' /proc/kallsyms | grep ' sched'
ffffffff817827d8 d sched_nr_latency
ffffffff81782ce0 d sched_domains_mutex
ffffffff8178c070 d schedstr.22423
ffffffff817909a0 d sched_register_mutex
ffffffff81823490 d sched_feat_names
ffffffff81823558 d scheduler_running
ffffffff818235b8 d sched_clock_running
ffffffff818235bc D sched_clock_stable
ffffffff81824f00 d sched_switch_trace
[root@doppio linux-2.6-tip]# perf top -s 0xffffffff817827d9
addr 0xffffffff817827d9 is in sched_nr_latency global var
[root@doppio linux-2.6-tip]# perf top -s ffffffff81782ce0
addr 0xffffffff81782ce0 is in sched_domains_mutex global var
[root@doppio linux-2.6-tip]#
[root@doppio linux-2.6-tip]# perf top -s ffffffff81782ce0 --vmlinux OFF
The file OFF cannot be used, trying to use /proc/kallsyms...addr 0xffffffff81782ce0 is in sched_domains_mutex global var
[root@doppio linux-2.6-tip]# perf top -s ffffffff818235bc --vmlinux OFF
The file OFF cannot be used, trying to use /proc/kallsyms...addr 0xffffffff818235bc is in sched_clock_stable global var
[root@doppio linux-2.6-tip]#

So it works with both /proc/kallsyms and with ELF symtabs, either
the one on the vmlinux explicitely passed via --vmlinux or in one
in the vmlinux_path that matches the buildid for the running kernel
or the one found in the buildid header section in a perf.data file.

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: <1260550239-5372-4-git-send-email-acme@infradead.org>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent d45868d3

tools/perf/util/event.h

+2 −1
Original line number Diff line number Diff line
@@ -103,9 +103,10 @@ void event__print_totals(void); 


enum map_type {

	MAP__FUNCTION = 0,

	MAP__VARIABLE,

};



#define MAP__NR_TYPES (MAP__FUNCTION + 1)

#define MAP__NR_TYPES (MAP__VARIABLE + 1)



struct map {

	union {

tools/perf/util/symbol.c

+51 −15
Original line number Diff line number Diff line
@@ -61,6 +61,8 @@ static bool symbol_type__is_a(char symbol_type, enum map_type map_type) 
	switch (map_type) {

	case MAP__FUNCTION:

		return symbol_type == 'T' || symbol_type == 'W';

	case MAP__VARIABLE:

		return symbol_type == 'D' || symbol_type == 'd';

	default:

		return false;

	}
@@ -551,6 +553,13 @@ static inline int elf_sym__is_function(const GElf_Sym *sym) 
	       sym->st_shndx != SHN_UNDEF;

}



static inline bool elf_sym__is_object(const GElf_Sym *sym)

{

	return elf_sym__type(sym) == STT_OBJECT &&

		sym->st_name != 0 &&

		sym->st_shndx != SHN_UNDEF;

}



static inline int elf_sym__is_label(const GElf_Sym *sym)

{

	return elf_sym__type(sym) == STT_NOTYPE &&
@@ -571,6 +580,12 @@ static inline int elf_sec__is_text(const GElf_Shdr *shdr, 
	return strstr(elf_sec__name(shdr, secstrs), "text") != NULL;

}



static inline bool elf_sec__is_data(const GElf_Shdr *shdr,

				    const Elf_Data *secstrs)

{

	return strstr(elf_sec__name(shdr, secstrs), "data") != NULL;

}



static inline const char *elf_sym__name(const GElf_Sym *sym,

					const Elf_Data *symstrs)

{
@@ -756,6 +771,8 @@ static bool elf_sym__is_a(GElf_Sym *self, enum map_type type) 
	switch (type) {

	case MAP__FUNCTION:

		return elf_sym__is_function(self);

	case MAP__VARIABLE:

		return elf_sym__is_object(self);

	default:

		return false;

	}
@@ -766,6 +783,8 @@ static bool elf_sec__is_a(GElf_Shdr *self, Elf_Data *secstrs, enum map_type type 
	switch (type) {

	case MAP__FUNCTION:

		return elf_sec__is_text(self, secstrs);

	case MAP__VARIABLE:

		return elf_sec__is_data(self, secstrs);

	default:

		return false;

	}
@@ -1536,44 +1555,61 @@ size_t dsos__fprintf_buildid(FILE *fp) 
		__dsos__fprintf_buildid(&dsos__user, fp));

}



static int map_groups__create_kernel_map(struct map_groups *self, const char *vmlinux)

static struct dso *dsos__create_kernel( const char *vmlinux)

{

	struct map *kmap;

	struct dso *kernel = dso__new(vmlinux ?: "[kernel.kallsyms]");



	if (kernel == NULL)

		return -1;



	kmap = map__new2(0, kernel, MAP__FUNCTION);

	if (kmap == NULL)

		goto out_delete_kernel_dso;

		return NULL;



	kmap->map_ip	   = kmap->unmap_ip = identity__map_ip;

	kernel->short_name = "[kernel]";

	kernel->kernel	   = 1;



	vdso = dso__new("[vdso]");

	if (vdso == NULL)

		goto out_delete_kernel_map;

		goto out_delete_kernel_dso;

	dso__set_loaded(vdso, MAP__FUNCTION);



	if (sysfs__read_build_id("/sys/kernel/notes", kernel->build_id,

				 sizeof(kernel->build_id)) == 0)

		kernel->has_build_id = true;



	map_groups__insert(self, kmap);

	dsos__add(&dsos__kernel, kernel);

	dsos__add(&dsos__user, vdso);



	return 0;

	return kernel;



out_delete_kernel_map:

	map__delete(kmap);

out_delete_kernel_dso:

	dso__delete(kernel);

	return NULL;

}



static int map_groups__create_kernel_maps(struct map_groups *self, const char *vmlinux)

{

	struct map *functions, *variables;

	struct dso *kernel = dsos__create_kernel(vmlinux);



	if (kernel == NULL)

		return -1;



	functions = map__new2(0, kernel, MAP__FUNCTION);

	if (functions == NULL)

		return -1;



	variables = map__new2(0, kernel, MAP__VARIABLE);

	if (variables == NULL) {

		map__delete(functions);

		return -1;

	}



	functions->map_ip = functions->unmap_ip =

		variables->map_ip = variables->unmap_ip = identity__map_ip;

	map_groups__insert(self, functions);

	map_groups__insert(self, variables);



	return 0;

}



static void vmlinux_path__exit(void)

{

	while (--vmlinux_path__nr_entries >= 0) {
@@ -1640,7 +1676,7 @@ int symbol__init(struct symbol_conf *conf) 
	if (pconf->try_vmlinux_path && vmlinux_path__init() < 0)

		return -1;



	if (map_groups__create_kernel_map(kmaps, pconf->vmlinux_name) < 0) {

	if (map_groups__create_kernel_maps(kmaps, pconf->vmlinux_name) < 0) {

		vmlinux_path__exit();

		return -1;

	}