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perf probe: Add basic module support

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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>
This commit is contained in:
Masami Hiramatsu
2010-10-21 19:13:41 +09:00
committed by Arnaldo Carvalho de Melo
parent fb8c5a56c7
commit 469b9b8848
7 changed files with 240 additions and 70 deletions
Download Patch File Download Diff File Expand all files Collapse all files

142
tools/perf/util/probe-finder.c
View File

@@ -116,6 +116,101 @@ static void line_list__free(struct list_head *head)
}
}
/* 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 @@ static int find_probes(int fd, struct probe_finder *pf)
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 @@ static int find_probes(int fd, struct probe_finder *pf)
off = noff;
}
line_list__free(&pf->lcache);
dwarf_end(dbg);
if (dwfl)
dwfl_end(dwfl);
return ret;
}
@@ -1412,23 +1510,31 @@ int find_available_vars_at(int fd, struct perf_probe_event *pev,
}
/* 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 @@ found:
}
end:
dwarf_end(dbg);
if (dwfl)
dwfl_end(dwfl);
if (ret >= 0)
ret = found ? 1 : 0;
return ret;
@@ -1624,6 +1731,8 @@ static int line_range_search_cb(Dwarf_Die *sp_die, void *data)
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 @@ int find_line_range(int fd, struct line_range *lr)
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 @@ int find_line_range(int fd, struct line_range *lr)
}
pr_debug("path: %s\n", lr->path);
dwarf_end(dbg);
dwfl_end(dwfl);
return (ret < 0) ? ret : lf.found;
}