Commit 2e538c4a authored by Arnaldo Carvalho de Melo's avatar Arnaldo Carvalho de Melo Committed by Ingo Molnar

perf tools: Improve kernel/modules symbol lookup

This removes the ovelapping of vmlinux addresses with modules,
using the ELF section name when using --vmlinux and creating a
unique DSO name when using /proc/kallsyms ([kernel].N).

This is done by creating multiple 'struct map' instances for
address ranges backed by DSOs that have just the symbols for that
range and a name that is derived from the ELF section name.o

Now it is possible to ask for just the symbols in some particular
kernel section:

$ perf report -m --vmlinux ../build/tip-recvmmsg/vmlinux \
	--dsos [kernel].vsyscall_fn | head -15
    52.73%             Xorg  [.] vread_hpet
    18.61%          firefox  [.] vread_hpet
    14.50%     npviewer.bin  [.] vread_hpet
     6.83%           compiz  [.] vread_hpet
     5.73%         glxgears  [.] vread_hpet
     0.63%             java  [.] vread_hpet
     0.30%   gnome-terminal  [.] vread_hpet
     0.23%             perf  [.] vread_hpet
     0.18%            xchat  [.] vread_hpet
$

Now we don't have to first lookup the list of modules and then, if
it fails, vmlinux symbols, its just a simple lookup for the map
then the symbols, just like for threads.

Reports generated using /proc/kallsyms and --vmlinux should provide
the same results, modulo the DSO name for sections other than
".text".

But they don't right now because things like:

 ffffffff81011c20-ffffffff81012068 system_call
 ffffffff81011c30-ffffffff81011c9b system_call_after_swapgs
 ffffffff81011c9c-ffffffff81011cb6 system_call_fastpath
 ffffffff81011cb7-ffffffff81011cbb ret_from_sys_call

I.e. overlapping symbols, again some ASM special case that we have
to fixup.
Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Mike Galbraith <efault@gmx.de>
LKML-Reference: <1254934136-8503-1-git-send-email-acme@redhat.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent da21d1b5
......@@ -26,27 +26,35 @@ enum dso_origin {
static void dsos__add(struct dso *dso);
static struct dso *dsos__find(const char *name);
static struct map *map__new2(u64 start, struct dso *dso);
static void kernel_maps__insert(struct map *map);
static struct rb_root kernel_maps;
static void dso__set_symbols_end(struct dso *self)
static void dso__fixup_sym_end(struct dso *self)
{
struct rb_node *nd, *prevnd = rb_first(&self->syms);
struct symbol *curr, *prev;
if (prevnd == NULL)
return;
curr = rb_entry(prevnd, struct symbol, rb_node);
for (nd = rb_next(prevnd); nd; nd = rb_next(nd)) {
struct symbol *prev = rb_entry(prevnd, struct symbol, rb_node),
*curr = rb_entry(nd, struct symbol, rb_node);
prev = curr;
curr = rb_entry(nd, struct symbol, rb_node);
if (prev->end == prev->start)
prev->end = curr->start - 1;
prevnd = nd;
}
/* Last entry */
if (curr->end == curr->start)
curr->end = roundup(curr->start, 4096);
}
static void kernel_maps__fixup_sym_end(void)
static void kernel_maps__fixup_end(void)
{
struct map *prev, *curr;
struct rb_node *nd, *prevnd = rb_first(&kernel_maps);
......@@ -55,13 +63,17 @@ static void kernel_maps__fixup_sym_end(void)
return;
curr = rb_entry(prevnd, struct map, rb_node);
dso__set_symbols_end(curr->dso);
for (nd = rb_next(prevnd); nd; nd = rb_next(nd)) {
prev = curr;
curr = rb_entry(nd, struct map, rb_node);
prev->end = curr->start - 1;
dso__set_symbols_end(curr->dso);
}
nd = rb_last(&curr->dso->syms);
if (nd) {
struct symbol *sym = rb_entry(nd, struct symbol, rb_node);
curr->end = sym->end;
}
}
......@@ -200,13 +212,16 @@ size_t dso__fprintf(struct dso *self, FILE *fp)
return ret;
}
static int maps__load_kallsyms(symbol_filter_t filter, int use_modules, int v)
/*
* Loads the function entries in /proc/kallsyms into kernel_map->dso,
* so that we can in the next step set the symbol ->end address and then
* call kernel_maps__split_kallsyms.
*/
static int kernel_maps__load_all_kallsyms(int v)
{
struct map *map = kernel_map;
char *line = NULL;
size_t n;
FILE *file = fopen("/proc/kallsyms", "r");
int count = 0;
if (file == NULL)
goto out_failure;
......@@ -216,7 +231,7 @@ static int maps__load_kallsyms(symbol_filter_t filter, int use_modules, int v)
struct symbol *sym;
int line_len, len;
char symbol_type;
char *module, *symbol_name;
char *symbol_name;
line_len = getline(&line, &n, file);
if (line_len < 0)
......@@ -241,20 +256,55 @@ static int maps__load_kallsyms(symbol_filter_t filter, int use_modules, int v)
continue;
symbol_name = line + len + 2;
module = strchr(symbol_name, '\t');
if (module) {
char *module_name_end;
/*
* Will fix up the end later, when we have all symbols sorted.
*/
sym = symbol__new(start, 0, symbol_name,
kernel_map->dso->sym_priv_size, v);
if (sym == NULL)
goto out_delete_line;
dso__insert_symbol(kernel_map->dso, sym);
}
free(line);
fclose(file);
return 0;
out_delete_line:
free(line);
out_failure:
return -1;
}
/*
* Split the symbols into maps, making sure there are no overlaps, i.e. the
* kernel range is broken in several maps, named [kernel].N, as we don't have
* the original ELF section names vmlinux have.
*/
static int kernel_maps__split_kallsyms(symbol_filter_t filter, int use_modules)
{
struct map *map = kernel_map;
struct symbol *pos;
int count = 0;
struct rb_node *next = rb_first(&kernel_map->dso->syms);
int kernel_range = 0;
while (next) {
char *module;
pos = rb_entry(next, struct symbol, rb_node);
next = rb_next(&pos->rb_node);
module = strchr(pos->name, '\t');
if (module) {
if (!use_modules)
continue;
*module = '\0';
module = strchr(module + 1, '[');
if (!module)
continue;
module_name_end = strchr(module + 1, ']');
if (!module_name_end)
continue;
*(module_name_end + 1) = '\0';
goto delete_symbol;
*module++ = '\0';
if (strcmp(map->dso->name, module)) {
map = kernel_maps__find_by_dso_name(module);
if (!map) {
......@@ -263,50 +313,77 @@ static int maps__load_kallsyms(symbol_filter_t filter, int use_modules, int v)
return -1;
}
}
start = map->map_ip(map, start);
} else
map = kernel_map;
/*
* Well fix up the end later, when we have all sorted.
* So that we look just like we get from .ko files,
* i.e. not prelinked, relative to map->start.
*/
sym = symbol__new(start, 0, symbol_name,
map->dso->sym_priv_size, v);
pos->start = map->map_ip(map, pos->start);
pos->end = map->map_ip(map, pos->end);
} else if (map != kernel_map) {
char dso_name[PATH_MAX];
struct dso *dso;
if (sym == NULL)
goto out_delete_line;
snprintf(dso_name, sizeof(dso_name), "[kernel].%d",
kernel_range++);
if (filter && filter(map, sym))
symbol__delete(sym, map->dso->sym_priv_size);
else {
dso__insert_symbol(map->dso, sym);
count++;
dso = dso__new(dso_name,
kernel_map->dso->sym_priv_size);
if (dso == NULL)
return -1;
map = map__new2(pos->start, dso);
if (map == NULL) {
dso__delete(dso);
return -1;
}
map->map_ip = vdso__map_ip;
kernel_maps__insert(map);
++kernel_range;
}
free(line);
fclose(file);
if (filter && filter(map, pos)) {
delete_symbol:
rb_erase(&pos->rb_node, &kernel_map->dso->syms);
symbol__delete(pos, kernel_map->dso->sym_priv_size);
} else {
if (map != kernel_map) {
rb_erase(&pos->rb_node, &kernel_map->dso->syms);
dso__insert_symbol(map->dso, pos);
}
count++;
}
}
return count;
}
out_delete_line:
free(line);
out_failure:
static int kernel_maps__load_kallsyms(symbol_filter_t filter,
int use_modules, int v)
{
if (kernel_maps__load_all_kallsyms(v))
return -1;
dso__fixup_sym_end(kernel_map->dso);
return kernel_maps__split_kallsyms(filter, use_modules);
}
static size_t kernel_maps__fprintf(FILE *fp)
static size_t kernel_maps__fprintf(FILE *fp, int v)
{
size_t printed = fprintf(stderr, "Kernel maps:\n");
struct rb_node *nd;
printed += map__fprintf(kernel_map, fp);
printed += dso__fprintf(kernel_map->dso, fp);
for (nd = rb_first(&kernel_maps); nd; nd = rb_next(nd)) {
struct map *pos = rb_entry(nd, struct map, rb_node);
printed += fprintf(fp, "Map:");
printed += map__fprintf(pos, fp);
if (v > 1) {
printed += dso__fprintf(pos->dso, fp);
printed += fprintf(fp, "--\n");
}
}
return printed + fprintf(stderr, "END kernel maps\n");
......@@ -594,6 +671,9 @@ static int dso__load_sym(struct dso *self, struct map *map, const char *name,
int fd, symbol_filter_t filter, int kernel,
int kmodule, int v)
{
struct map *curr_map = map;
struct dso *curr_dso = self;
size_t dso_name_len = strlen(self->short_name);
Elf_Data *symstrs, *secstrs;
uint32_t nr_syms;
int err = -1;
......@@ -660,10 +740,9 @@ static int dso__load_sym(struct dso *self, struct map *map, const char *name,
elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) {
struct symbol *f;
const char *elf_name;
char *demangled;
char *demangled = NULL;
int is_label = elf_sym__is_label(&sym);
const char *section_name;
u64 sh_offset = 0;
if (!is_label && !elf_sym__is_function(&sym))
continue;
......@@ -677,14 +756,51 @@ static int dso__load_sym(struct dso *self, struct map *map, const char *name,
if (is_label && !elf_sec__is_text(&shdr, secstrs))
continue;
elf_name = elf_sym__name(&sym, symstrs);
section_name = elf_sec__name(&shdr, secstrs);
if ((kernel || kmodule)) {
if (strstr(section_name, ".init"))
sh_offset = shdr.sh_offset;
if (kernel || kmodule) {
char dso_name[PATH_MAX];
if (strcmp(section_name,
curr_dso->short_name + dso_name_len) == 0)
goto new_symbol;
if (strcmp(section_name, ".text") == 0) {
curr_map = map;
curr_dso = self;
goto new_symbol;
}
snprintf(dso_name, sizeof(dso_name),
"%s%s", self->short_name, section_name);
curr_map = kernel_maps__find_by_dso_name(dso_name);
if (curr_map == NULL) {
u64 start = sym.st_value;
if (kmodule)
start += map->start + shdr.sh_offset;
curr_dso = dso__new(dso_name, self->sym_priv_size);
if (curr_dso == NULL)
goto out_elf_end;
curr_map = map__new2(start, curr_dso);
if (curr_map == NULL) {
dso__delete(curr_dso);
goto out_elf_end;
}
curr_map->map_ip = vdso__map_ip;
curr_dso->origin = DSO__ORIG_KERNEL;
kernel_maps__insert(curr_map);
dsos__add(curr_dso);
} else
curr_dso = curr_map->dso;
goto new_symbol;
}
if (self->adjust_symbols) {
if (curr_dso->adjust_symbols) {
if (v > 2)
printf("adjusting symbol: st_value: %Lx sh_addr: %Lx sh_offset: %Lx\n",
(u64)sym.st_value, (u64)shdr.sh_addr, (u64)shdr.sh_offset);
......@@ -696,25 +812,29 @@ static int dso__load_sym(struct dso *self, struct map *map, const char *name,
* DWARF DW_compile_unit has this, but we don't always have access
* to it...
*/
elf_name = elf_sym__name(&sym, symstrs);
demangled = bfd_demangle(NULL, elf_name, DMGL_PARAMS | DMGL_ANSI);
if (demangled != NULL)
elf_name = demangled;
f = symbol__new(sym.st_value + sh_offset, sym.st_size, elf_name,
self->sym_priv_size, v);
new_symbol:
f = symbol__new(sym.st_value, sym.st_size, elf_name,
curr_dso->sym_priv_size, v);
free(demangled);
if (!f)
goto out_elf_end;
if (filter && filter(map, f))
symbol__delete(f, self->sym_priv_size);
if (filter && filter(curr_map, f))
symbol__delete(f, curr_dso->sym_priv_size);
else {
dso__insert_symbol(self, f);
dso__insert_symbol(curr_dso, f);
nr++;
}
}
/*
* For misannotated, zeroed, ASM function sizes.
*/
if (nr > 0)
dso__fixup_sym_end(self);
err = nr;
out_elf_end:
elf_end(elf);
......@@ -883,27 +1003,17 @@ static void kernel_maps__insert(struct map *map)
struct symbol *kernel_maps__find_symbol(u64 ip, struct map **mapp)
{
/*
* We can't have kernel_map in kernel_maps because it spans an address
* space that includes the modules. The right way to fix this is to
* create several maps, so that we don't have overlapping ranges with
* modules. For now lets look first on the kernel dso.
*/
struct map *map = maps__find(&kernel_maps, ip);
struct symbol *sym;
if (mapp)
*mapp = map;
if (map) {
ip = map->map_ip(map, ip);
sym = map->dso->find_symbol(map->dso, ip);
} else {
map = kernel_map;
sym = map->dso->find_symbol(map->dso, ip);
return map->dso->find_symbol(map->dso, ip);
}
if (mapp)
*mapp = map;
return sym;
return NULL;
}
struct map *kernel_maps__find_by_dso_name(const char *name)
......@@ -994,6 +1104,14 @@ static int dsos__load_modules_sym_dir(char *dirname,
last = rb_last(&map->dso->syms);
if (last) {
struct symbol *sym;
/*
* We do this here as well, even having the
* symbol size found in the symtab because
* misannotated ASM symbols may have the size
* set to zero.
*/
dso__fixup_sym_end(map->dso);
sym = rb_entry(last, struct symbol, rb_node);
map->end = map->start + sym->end;
}
......@@ -1163,17 +1281,11 @@ int dsos__load_kernel(const char *vmlinux, unsigned int sym_priv_size,
}
if (err <= 0)
err = maps__load_kallsyms(filter, use_modules, v);
err = kernel_maps__load_kallsyms(filter, use_modules, v);
if (err > 0) {
struct rb_node *node = rb_first(&dso->syms);
struct symbol *sym = rb_entry(node, struct symbol, rb_node);
/*
* Now that we have all sorted out, just set the ->end of all
* symbols that still don't have it.
*/
dso__set_symbols_end(dso);
kernel_maps__fixup_sym_end();
kernel_map->start = sym->start;
node = rb_last(&dso->syms);
......@@ -1181,14 +1293,16 @@ int dsos__load_kernel(const char *vmlinux, unsigned int sym_priv_size,
kernel_map->end = sym->end;
dso->origin = DSO__ORIG_KERNEL;
kernel_maps__insert(kernel_map);
/*
* XXX See kernel_maps__find_symbol comment
* kernel_maps__insert(kernel_map)
* Now that we have all sorted out, just set the ->end of all
* maps:
*/
kernel_maps__fixup_end();
dsos__add(dso);
if (v > 0)
kernel_maps__fprintf(stderr);
kernel_maps__fprintf(stderr, v);
}
return err;
......
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