[PATCH 1/1] perf tools: Improve kernel/modules symbol lookup
From: Arnaldo Carvalho de Melo
Date: Wed Oct 07 2009 - 12:50:30 EST
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.
Cc: Frederic Weisbecker <fweisbec@xxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Paul Mackerras <paulus@xxxxxxxxx>
Cc: Mike Galbraith <efault@xxxxxx>
Cc: Paul Mackerras <paulus@xxxxxxxxx>
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
---
tools/perf/util/symbol.c | 288 ++++++++++++++++++++++++++++++++--------------
1 files changed, 201 insertions(+), 87 deletions(-)
diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c
index a6887f9..faa84f5 100644
--- a/tools/perf/util/symbol.c
+++ b/tools/perf/util/symbol.c
@@ -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.
- */
- sym = symbol__new(start, 0, symbol_name,
- map->dso->sym_priv_size, v);
+ /*
+ * So that we look just like we get from .ko files,
+ * i.e. not prelinked, relative to map->start.
+ */
+ 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;
+
+ snprintf(dso_name, sizeof(dso_name), "[kernel].%d",
+ kernel_range++);
+
+ 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;
+ }
- if (sym == NULL)
- goto out_delete_line;
+ map->map_ip = vdso__map_ip;
+ kernel_maps__insert(map);
+ ++kernel_range;
+ }
- if (filter && filter(map, sym))
- symbol__delete(sym, map->dso->sym_priv_size);
- else {
- dso__insert_symbol(map->dso, sym);
+ 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++;
}
}
- free(line);
- fclose(file);
-
return count;
+}
-out_delete_line:
- free(line);
-out_failure:
- return -1;
+
+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);
- printed += dso__fprintf(pos->dso, 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;
--
1.6.2.5
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