perf probe: Add basic module support
Add basic module probe support on perf probe. This introduces "--module
<MODNAME>" option to perf probe for putting probes and showing lines and
variables in the given module.
Currently, this supports only probing on running modules. Supporting off-line
module probing is the next step.
e.g.)
[show lines]
# ./perf probe --module drm -L drm_vblank_info
<drm_vblank_info:0>
0 int drm_vblank_info(struct seq_file *m, void *data)
1 {
struct drm_info_node *node = (struct drm_info_node *) m->private
3 struct drm_device *dev = node->minor->dev;
...
[show vars]
# ./perf probe --module drm -V drm_vblank_info:3
Available variables at drm_vblank_info:3
@<drm_vblank_info+20>
(unknown_type) data
struct drm_info_node* node
struct seq_file* m
[put a probe]
# ./perf probe --module drm drm_vblank_info:3 node m
Add new event:
probe:drm_vblank_info (on drm_vblank_info:3 with node m)
You can now use it on all perf tools, such as:
perf record -e probe:drm_vblank_info -aR sleep 1
[list probes]
# ./perf probe -l
probe:drm_vblank_info (on drm_vblank_info:3@drivers/gpu/drm/drm_info.c with ...
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <20101021101341.3542.71638.stgit@ltc236.sdl.hitachi.co.jp>
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
diff --git a/tools/perf/util/map.h b/tools/perf/util/map.h
index 7857579..b397c03 100644
--- a/tools/perf/util/map.h
+++ b/tools/perf/util/map.h
@@ -215,6 +215,16 @@
return map_groups__find_symbol_by_name(self, MAP__FUNCTION, name, mapp, filter);
}
+static inline
+struct symbol *machine__find_kernel_function_by_name(struct machine *self,
+ const char *name,
+ struct map **mapp,
+ symbol_filter_t filter)
+{
+ return map_groups__find_function_by_name(&self->kmaps, name, mapp,
+ filter);
+}
+
int map_groups__fixup_overlappings(struct map_groups *self, struct map *map,
int verbose, FILE *fp);
diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
index 82b0976..3b6a529 100644
--- a/tools/perf/util/probe-event.c
+++ b/tools/perf/util/probe-event.c
@@ -74,10 +74,9 @@
static char *synthesize_perf_probe_point(struct perf_probe_point *pp);
static struct machine machine;
-/* Initialize symbol maps and path of vmlinux */
+/* Initialize symbol maps and path of vmlinux/modules */
static int init_vmlinux(void)
{
- struct dso *kernel;
int ret;
symbol_conf.sort_by_name = true;
@@ -91,33 +90,61 @@
goto out;
}
- ret = machine__init(&machine, "/", 0);
+ ret = machine__init(&machine, "", HOST_KERNEL_ID);
if (ret < 0)
goto out;
- kernel = dso__new_kernel(symbol_conf.vmlinux_name);
- if (kernel == NULL)
- die("Failed to create kernel dso.");
-
- ret = __machine__create_kernel_maps(&machine, kernel);
- if (ret < 0)
- pr_debug("Failed to create kernel maps.\n");
-
+ if (machine__create_kernel_maps(&machine) < 0) {
+ pr_debug("machine__create_kernel_maps ");
+ goto out;
+ }
out:
if (ret < 0)
pr_warning("Failed to init vmlinux path.\n");
return ret;
}
-#ifdef DWARF_SUPPORT
-static int open_vmlinux(void)
+static struct symbol *__find_kernel_function_by_name(const char *name,
+ struct map **mapp)
{
- if (map__load(machine.vmlinux_maps[MAP__FUNCTION], NULL) < 0) {
- pr_debug("Failed to load kernel map.\n");
- return -EINVAL;
+ return machine__find_kernel_function_by_name(&machine, name, mapp,
+ NULL);
+}
+
+const char *kernel_get_module_path(const char *module)
+{
+ struct dso *dso;
+
+ if (module) {
+ list_for_each_entry(dso, &machine.kernel_dsos, node) {
+ if (strncmp(dso->short_name + 1, module,
+ dso->short_name_len - 2) == 0)
+ goto found;
+ }
+ pr_debug("Failed to find module %s.\n", module);
+ return NULL;
+ } else {
+ dso = machine.vmlinux_maps[MAP__FUNCTION]->dso;
+ if (dso__load_vmlinux_path(dso,
+ machine.vmlinux_maps[MAP__FUNCTION], NULL) < 0) {
+ pr_debug("Failed to load kernel map.\n");
+ return NULL;
+ }
}
- pr_debug("Try to open %s\n", machine.vmlinux_maps[MAP__FUNCTION]->dso->long_name);
- return open(machine.vmlinux_maps[MAP__FUNCTION]->dso->long_name, O_RDONLY);
+found:
+ return dso->long_name;
+}
+
+#ifdef DWARF_SUPPORT
+static int open_vmlinux(const char *module)
+{
+ const char *path = kernel_get_module_path(module);
+ if (!path) {
+ pr_err("Failed to find path of %s module", module ?: "kernel");
+ return -ENOENT;
+ }
+ pr_debug("Try to open %s\n", path);
+ return open(path, O_RDONLY);
}
/*
@@ -125,20 +152,19 @@
* Currently only handles kprobes.
*/
static int kprobe_convert_to_perf_probe(struct probe_trace_point *tp,
- struct perf_probe_point *pp)
+ struct perf_probe_point *pp)
{
struct symbol *sym;
- int fd, ret = -ENOENT;
+ struct map *map;
+ u64 addr;
+ int ret = -ENOENT;
- sym = map__find_symbol_by_name(machine.vmlinux_maps[MAP__FUNCTION],
- tp->symbol, NULL);
+ sym = __find_kernel_function_by_name(tp->symbol, &map);
if (sym) {
- fd = open_vmlinux();
- if (fd >= 0) {
- ret = find_perf_probe_point(fd,
- sym->start + tp->offset, pp);
- close(fd);
- }
+ addr = map->unmap_ip(map, sym->start + tp->offset);
+ pr_debug("try to find %s+%ld@%llx\n", tp->symbol,
+ tp->offset, addr);
+ ret = find_perf_probe_point((unsigned long)addr, pp);
}
if (ret <= 0) {
pr_debug("Failed to find corresponding probes from "
@@ -156,12 +182,12 @@
/* Try to find perf_probe_event with debuginfo */
static int try_to_find_probe_trace_events(struct perf_probe_event *pev,
struct probe_trace_event **tevs,
- int max_tevs)
+ int max_tevs, const char *module)
{
bool need_dwarf = perf_probe_event_need_dwarf(pev);
int fd, ntevs;
- fd = open_vmlinux();
+ fd = open_vmlinux(module);
if (fd < 0) {
if (need_dwarf) {
pr_warning("Failed to open debuginfo file.\n");
@@ -300,7 +326,7 @@
* Show line-range always requires debuginfo to find source file and
* line number.
*/
-int show_line_range(struct line_range *lr)
+int show_line_range(struct line_range *lr, const char *module)
{
int l = 1;
struct line_node *ln;
@@ -313,7 +339,7 @@
if (ret < 0)
return ret;
- fd = open_vmlinux();
+ fd = open_vmlinux(module);
if (fd < 0) {
pr_warning("Failed to open debuginfo file.\n");
return fd;
@@ -421,7 +447,7 @@
/* Show available variables on given probe point */
int show_available_vars(struct perf_probe_event *pevs, int npevs,
- int max_vls, bool externs)
+ int max_vls, const char *module, bool externs)
{
int i, fd, ret = 0;
@@ -429,7 +455,7 @@
if (ret < 0)
return ret;
- fd = open_vmlinux();
+ fd = open_vmlinux(module);
if (fd < 0) {
pr_warning("Failed to open debuginfo file.\n");
return fd;
@@ -447,8 +473,15 @@
#else /* !DWARF_SUPPORT */
static int kprobe_convert_to_perf_probe(struct probe_trace_point *tp,
- struct perf_probe_point *pp)
+ struct perf_probe_point *pp)
{
+ struct symbol *sym;
+
+ sym = __find_kernel_function_by_name(tp->symbol, NULL);
+ if (!sym) {
+ pr_err("Failed to find symbol %s in kernel.\n", tp->symbol);
+ return -ENOENT;
+ }
pp->function = strdup(tp->symbol);
if (pp->function == NULL)
return -ENOMEM;
@@ -460,7 +493,7 @@
static int try_to_find_probe_trace_events(struct perf_probe_event *pev,
struct probe_trace_event **tevs __unused,
- int max_tevs __unused)
+ int max_tevs __unused, const char *mod __unused)
{
if (perf_probe_event_need_dwarf(pev)) {
pr_warning("Debuginfo-analysis is not supported.\n");
@@ -469,14 +502,15 @@
return 0;
}
-int show_line_range(struct line_range *lr __unused)
+int show_line_range(struct line_range *lr __unused, const char *module __unused)
{
pr_warning("Debuginfo-analysis is not supported.\n");
return -ENOSYS;
}
int show_available_vars(struct perf_probe_event *pevs __unused,
- int npevs __unused, int max_probe_points __unused)
+ int npevs __unused, int max_vls __unused,
+ const char *module __unused, bool externs __unused)
{
pr_warning("Debuginfo-analysis is not supported.\n");
return -ENOSYS;
@@ -1159,7 +1193,7 @@
}
static int convert_to_perf_probe_event(struct probe_trace_event *tev,
- struct perf_probe_event *pev)
+ struct perf_probe_event *pev)
{
char buf[64] = "";
int i, ret;
@@ -1588,14 +1622,14 @@
static int convert_to_probe_trace_events(struct perf_probe_event *pev,
struct probe_trace_event **tevs,
- int max_tevs)
+ int max_tevs, const char *module)
{
struct symbol *sym;
int ret = 0, i;
struct probe_trace_event *tev;
/* Convert perf_probe_event with debuginfo */
- ret = try_to_find_probe_trace_events(pev, tevs, max_tevs);
+ ret = try_to_find_probe_trace_events(pev, tevs, max_tevs, module);
if (ret != 0)
return ret;
@@ -1644,8 +1678,7 @@
}
/* Currently just checking function name from symbol map */
- sym = map__find_symbol_by_name(machine.vmlinux_maps[MAP__FUNCTION],
- tev->point.symbol, NULL);
+ sym = __find_kernel_function_by_name(tev->point.symbol, NULL);
if (!sym) {
pr_warning("Kernel symbol \'%s\' not found.\n",
tev->point.symbol);
@@ -1668,7 +1701,7 @@
};
int add_perf_probe_events(struct perf_probe_event *pevs, int npevs,
- int max_tevs, bool force_add)
+ int max_tevs, const char *module, bool force_add)
{
int i, j, ret;
struct __event_package *pkgs;
@@ -1689,7 +1722,9 @@
pkgs[i].pev = &pevs[i];
/* Convert with or without debuginfo */
ret = convert_to_probe_trace_events(pkgs[i].pev,
- &pkgs[i].tevs, max_tevs);
+ &pkgs[i].tevs,
+ max_tevs,
+ module);
if (ret < 0)
goto end;
pkgs[i].ntevs = ret;
diff --git a/tools/perf/util/probe-event.h b/tools/perf/util/probe-event.h
index c74b1fd..5accbed 100644
--- a/tools/perf/util/probe-event.h
+++ b/tools/perf/util/probe-event.h
@@ -115,14 +115,18 @@
/* Command string to line-range */
extern int parse_line_range_desc(const char *cmd, struct line_range *lr);
+/* Internal use: Return kernel/module path */
+extern const char *kernel_get_module_path(const char *module);
extern int add_perf_probe_events(struct perf_probe_event *pevs, int npevs,
- int max_probe_points, bool force_add);
+ int max_probe_points, const char *module,
+ bool force_add);
extern int del_perf_probe_events(struct strlist *dellist);
extern int show_perf_probe_events(void);
-extern int show_line_range(struct line_range *lr);
+extern int show_line_range(struct line_range *lr, const char *module);
extern int show_available_vars(struct perf_probe_event *pevs, int npevs,
- int max_probe_points, bool externs);
+ int max_probe_points, const char *module,
+ bool externs);
/* Maximum index number of event-name postfix */
diff --git a/tools/perf/util/probe-finder.c b/tools/perf/util/probe-finder.c
index a274fd0..c20bd52 100644
--- a/tools/perf/util/probe-finder.c
+++ b/tools/perf/util/probe-finder.c
@@ -116,6 +116,101 @@
}
}
+/* Dwarf FL wrappers */
+
+static int __linux_kernel_find_elf(Dwfl_Module *mod,
+ void **userdata,
+ const char *module_name,
+ Dwarf_Addr base,
+ char **file_name, Elf **elfp)
+{
+ int fd;
+ const char *path = kernel_get_module_path(module_name);
+
+ if (path) {
+ fd = open(path, O_RDONLY);
+ if (fd >= 0) {
+ *file_name = strdup(path);
+ return fd;
+ }
+ }
+ /* If failed, try to call standard method */
+ return dwfl_linux_kernel_find_elf(mod, userdata, module_name, base,
+ file_name, elfp);
+}
+
+static char *debuginfo_path; /* Currently dummy */
+
+static const Dwfl_Callbacks offline_callbacks = {
+ .find_debuginfo = dwfl_standard_find_debuginfo,
+ .debuginfo_path = &debuginfo_path,
+
+ .section_address = dwfl_offline_section_address,
+
+ /* We use this table for core files too. */
+ .find_elf = dwfl_build_id_find_elf,
+};
+
+static const Dwfl_Callbacks kernel_callbacks = {
+ .find_debuginfo = dwfl_standard_find_debuginfo,
+ .debuginfo_path = &debuginfo_path,
+
+ .find_elf = __linux_kernel_find_elf,
+ .section_address = dwfl_linux_kernel_module_section_address,
+};
+
+/* Get a Dwarf from offline image */
+static Dwarf *dwfl_init_offline_dwarf(int fd, Dwfl **dwflp, Dwarf_Addr *bias)
+{
+ Dwfl_Module *mod;
+ Dwarf *dbg = NULL;
+
+ if (!dwflp)
+ return NULL;
+
+ *dwflp = dwfl_begin(&offline_callbacks);
+ if (!*dwflp)
+ return NULL;
+
+ mod = dwfl_report_offline(*dwflp, "", "", fd);
+ if (!mod)
+ goto error;
+
+ dbg = dwfl_module_getdwarf(mod, bias);
+ if (!dbg) {
+error:
+ dwfl_end(*dwflp);
+ *dwflp = NULL;
+ }
+ return dbg;
+}
+
+/* Get a Dwarf from live kernel image */
+static Dwarf *dwfl_init_live_kernel_dwarf(Dwarf_Addr addr, Dwfl **dwflp,
+ Dwarf_Addr *bias)
+{
+ Dwarf *dbg;
+
+ if (!dwflp)
+ return NULL;
+
+ *dwflp = dwfl_begin(&kernel_callbacks);
+ if (!*dwflp)
+ return NULL;
+
+ /* Load the kernel dwarves: Don't care the result here */
+ dwfl_linux_kernel_report_kernel(*dwflp);
+ dwfl_linux_kernel_report_modules(*dwflp);
+
+ dbg = dwfl_addrdwarf(*dwflp, addr, bias);
+ /* Here, check whether we could get a real dwarf */
+ if (!dbg) {
+ dwfl_end(*dwflp);
+ *dwflp = NULL;
+ }
+ return dbg;
+}
+
/* Dwarf wrappers */
/* Find the realpath of the target file. */
@@ -1177,10 +1272,12 @@
Dwarf_Off off, noff;
size_t cuhl;
Dwarf_Die *diep;
- Dwarf *dbg;
+ Dwarf *dbg = NULL;
+ Dwfl *dwfl;
+ Dwarf_Addr bias; /* Currently ignored */
int ret = 0;
- dbg = dwarf_begin(fd, DWARF_C_READ);
+ dbg = dwfl_init_offline_dwarf(fd, &dwfl, &bias);
if (!dbg) {
pr_warning("No dwarf info found in the vmlinux - "
"please rebuild with CONFIG_DEBUG_INFO=y.\n");
@@ -1221,7 +1318,8 @@
off = noff;
}
line_list__free(&pf->lcache);
- dwarf_end(dbg);
+ if (dwfl)
+ dwfl_end(dwfl);
return ret;
}
@@ -1412,23 +1510,31 @@
}
/* Reverse search */
-int find_perf_probe_point(int fd, unsigned long addr,
- struct perf_probe_point *ppt)
+int find_perf_probe_point(unsigned long addr, struct perf_probe_point *ppt)
{
Dwarf_Die cudie, spdie, indie;
- Dwarf *dbg;
+ Dwarf *dbg = NULL;
+ Dwfl *dwfl = NULL;
Dwarf_Line *line;
- Dwarf_Addr laddr, eaddr;
+ Dwarf_Addr laddr, eaddr, bias = 0;
const char *tmp;
int lineno, ret = 0;
bool found = false;
- dbg = dwarf_begin(fd, DWARF_C_READ);
- if (!dbg)
- return -EBADF;
+ /* Open the live linux kernel */
+ dbg = dwfl_init_live_kernel_dwarf(addr, &dwfl, &bias);
+ if (!dbg) {
+ pr_warning("No dwarf info found in the vmlinux - "
+ "please rebuild with CONFIG_DEBUG_INFO=y.\n");
+ ret = -EINVAL;
+ goto end;
+ }
+ /* Adjust address with bias */
+ addr += bias;
/* Find cu die */
- if (!dwarf_addrdie(dbg, (Dwarf_Addr)addr, &cudie)) {
+ if (!dwarf_addrdie(dbg, (Dwarf_Addr)addr - bias, &cudie)) {
+ pr_warning("No CU DIE is found at %lx\n", addr);
ret = -EINVAL;
goto end;
}
@@ -1491,7 +1597,8 @@
}
end:
- dwarf_end(dbg);
+ if (dwfl)
+ dwfl_end(dwfl);
if (ret >= 0)
ret = found ? 1 : 0;
return ret;
@@ -1624,6 +1731,8 @@
struct line_finder *lf = param->data;
struct line_range *lr = lf->lr;
+ pr_debug("find (%lx) %s\n", dwarf_dieoffset(sp_die),
+ dwarf_diename(sp_die));
if (dwarf_tag(sp_die) == DW_TAG_subprogram &&
die_compare_name(sp_die, lr->function)) {
lf->fname = dwarf_decl_file(sp_die);
@@ -1667,10 +1776,12 @@
Dwarf_Off off = 0, noff;
size_t cuhl;
Dwarf_Die *diep;
- Dwarf *dbg;
+ Dwarf *dbg = NULL;
+ Dwfl *dwfl;
+ Dwarf_Addr bias; /* Currently ignored */
const char *comp_dir;
- dbg = dwarf_begin(fd, DWARF_C_READ);
+ dbg = dwfl_init_offline_dwarf(fd, &dwfl, &bias);
if (!dbg) {
pr_warning("No dwarf info found in the vmlinux - "
"please rebuild with CONFIG_DEBUG_INFO=y.\n");
@@ -1716,8 +1827,7 @@
}
pr_debug("path: %s\n", lr->path);
- dwarf_end(dbg);
-
+ dwfl_end(dwfl);
return (ret < 0) ? ret : lf.found;
}
diff --git a/tools/perf/util/probe-finder.h b/tools/perf/util/probe-finder.h
index 516912a..bba69d4 100644
--- a/tools/perf/util/probe-finder.h
+++ b/tools/perf/util/probe-finder.h
@@ -22,7 +22,7 @@
int max_tevs);
/* Find a perf_probe_point from debuginfo */
-extern int find_perf_probe_point(int fd, unsigned long addr,
+extern int find_perf_probe_point(unsigned long addr,
struct perf_probe_point *ppt);
/* Find a line range */
@@ -35,6 +35,7 @@
#include <dwarf.h>
#include <libdw.h>
+#include <libdwfl.h>
#include <version.h>
struct probe_finder {