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Subject[tip:perf/core] perf probe: Show source-level or symbol-level info for uprobes
Commit-ID:  5a6f63145491f905de1c5c6c46c5cd62c004d0d1
Gitweb: http://git.kernel.org/tip/5a6f63145491f905de1c5c6c46c5cd62c004d0d1
Author: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
AuthorDate: Thu, 6 Feb 2014 05:32:23 +0000
Committer: Arnaldo Carvalho de Melo <acme@redhat.com>
CommitDate: Tue, 18 Feb 2014 09:34:51 -0300

perf probe: Show source-level or symbol-level info for uprobes

Show source-level or symbol-level information for uprobe events.

Without this change;
# ./perf probe -l
probe_perf:dso__load_vmlinux (on 0x000000000006d110 in /kbuild/ksrc/linux-3/tools/perf/perf)

With this change;
# ./perf probe -l
probe_perf:dso__load_vmlinux (on dso__load_vmlinux@util/symbol.c in /kbuild/ksrc/linux-3/tools/perf/perf)

Changes from v2:
- Update according to previous patches.

Changes from v1:
- Rewrite the code based on new series.

Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: "David A. Long" <dave.long@linaro.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: yrl.pp-manager.tt@hitachi.com
Link: http://lkml.kernel.org/r/20140206053223.29635.51280.stgit@kbuild-fedora.yrl.intra.hitachi.co.jp
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
tools/perf/util/probe-event.c | 227 +++++++++++++++++++++++++++---------------
1 file changed, 144 insertions(+), 83 deletions(-)

diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
index f86820c..3c35b7a 100644
--- a/tools/perf/util/probe-event.c
+++ b/tools/perf/util/probe-event.c
@@ -249,34 +249,6 @@ out:
return ret;
}

-static int convert_to_perf_probe_point(struct probe_trace_point *tp,
- struct perf_probe_point *pp)
-{
- struct symbol *sym;
- struct map *map;
- u64 addr = kernel_get_symbol_address_by_name(tp->symbol, true);
-
- if (addr) {
- addr += tp->offset;
- sym = __find_kernel_function(addr, &map);
- if (!sym)
- goto failed;
- pp->function = strdup(sym->name);
- pp->offset = addr - map->unmap_ip(map, sym->start);
- } else {
-failed:
- pp->function = strdup(tp->symbol);
- pp->offset = tp->offset;
- }
-
- if (pp->function == NULL)
- return -ENOMEM;
-
- pp->retprobe = tp->retprobe;
-
- return 0;
-}
-
#ifdef HAVE_DWARF_SUPPORT
/* Open new debuginfo of given module */
static struct debuginfo *open_debuginfo(const char *module)
@@ -298,44 +270,6 @@ static struct debuginfo *open_debuginfo(const char *module)
return debuginfo__new(path);
}

-/*
- * Convert trace point to probe point with debuginfo
- * Currently only handles kprobes.
- */
-static int kprobe_convert_to_perf_probe(struct probe_trace_point *tp,
- struct perf_probe_point *pp)
-{
- u64 addr = 0;
- int ret = -ENOENT;
- struct debuginfo *dinfo;
-
- addr = kernel_get_symbol_address_by_name(tp->symbol, false);
- if (addr) {
- addr += tp->offset;
- pr_debug("try to find %s+%ld@%" PRIx64 "\n", tp->symbol,
- tp->offset, addr);
-
- dinfo = open_debuginfo(tp->module);
- if (dinfo) {
- ret = debuginfo__find_probe_point(dinfo,
- (unsigned long)addr, pp);
- debuginfo__delete(dinfo);
- } else {
- pr_debug("Failed to open debuginfo at 0x%" PRIx64 "\n",
- addr);
- ret = -ENOENT;
- }
- }
- if (ret <= 0) {
- pr_debug("Failed to find corresponding probes from "
- "debuginfo. Use kprobe event information.\n");
- return convert_to_perf_probe_point(tp, pp);
- }
- pp->retprobe = tp->retprobe;
-
- return 0;
-}
-
static int get_text_start_address(const char *exec, unsigned long *address)
{
Elf *elf;
@@ -364,6 +298,57 @@ out:
return ret;
}

+/*
+ * Convert trace point to probe point with debuginfo
+ */
+static int find_perf_probe_point_from_dwarf(struct probe_trace_point *tp,
+ struct perf_probe_point *pp,
+ bool is_kprobe)
+{
+ struct debuginfo *dinfo = NULL;
+ unsigned long stext = 0;
+ u64 addr = tp->address;
+ int ret = -ENOENT;
+
+ /* convert the address to dwarf address */
+ if (!is_kprobe) {
+ if (!addr) {
+ ret = -EINVAL;
+ goto error;
+ }
+ ret = get_text_start_address(tp->module, &stext);
+ if (ret < 0)
+ goto error;
+ addr += stext;
+ } else {
+ addr = kernel_get_symbol_address_by_name(tp->symbol, false);
+ if (addr == 0)
+ goto error;
+ addr += tp->offset;
+ }
+
+ pr_debug("try to find information at %" PRIx64 " in %s\n", addr,
+ tp->module ? : "kernel");
+
+ dinfo = open_debuginfo(tp->module);
+ if (dinfo) {
+ ret = debuginfo__find_probe_point(dinfo,
+ (unsigned long)addr, pp);
+ debuginfo__delete(dinfo);
+ } else {
+ pr_debug("Failed to open debuginfo at 0x%" PRIx64 "\n", addr);
+ ret = -ENOENT;
+ }
+
+ if (ret > 0) {
+ pp->retprobe = tp->retprobe;
+ return 0;
+ }
+error:
+ pr_debug("Failed to find corresponding probes from debuginfo.\n");
+ return ret ? : -ENOENT;
+}
+
static int add_exec_to_probe_trace_events(struct probe_trace_event *tevs,
int ntevs, const char *exec)
{
@@ -815,10 +800,12 @@ out:

#else /* !HAVE_DWARF_SUPPORT */

-static int kprobe_convert_to_perf_probe(struct probe_trace_point *tp,
- struct perf_probe_point *pp)
+static int
+find_perf_probe_point_from_dwarf(struct probe_trace_point *tp __maybe_unused,
+ struct perf_probe_point *pp __maybe_unused,
+ bool is_kprobe __maybe_unused)
{
- return convert_to_perf_probe_point(tp, pp);
+ return -ENOSYS;
}

static int try_to_find_probe_trace_events(struct perf_probe_event *pev,
@@ -1343,16 +1330,21 @@ static int parse_probe_trace_command(const char *cmd,
} else
p = argv[1];
fmt1_str = strtok_r(p, "+", &fmt);
- tp->symbol = strdup(fmt1_str);
- if (tp->symbol == NULL) {
- ret = -ENOMEM;
- goto out;
+ if (fmt1_str[0] == '0') /* only the address started with 0x */
+ tp->address = strtoul(fmt1_str, NULL, 0);
+ else {
+ /* Only the symbol-based probe has offset */
+ tp->symbol = strdup(fmt1_str);
+ if (tp->symbol == NULL) {
+ ret = -ENOMEM;
+ goto out;
+ }
+ fmt2_str = strtok_r(NULL, "", &fmt);
+ if (fmt2_str == NULL)
+ tp->offset = 0;
+ else
+ tp->offset = strtoul(fmt2_str, NULL, 10);
}
- fmt2_str = strtok_r(NULL, "", &fmt);
- if (fmt2_str == NULL)
- tp->offset = 0;
- else
- tp->offset = strtoul(fmt2_str, NULL, 10);

tev->nargs = argc - 2;
tev->args = zalloc(sizeof(struct probe_trace_arg) * tev->nargs);
@@ -1623,6 +1615,79 @@ error:
return NULL;
}

+static int find_perf_probe_point_from_map(struct probe_trace_point *tp,
+ struct perf_probe_point *pp,
+ bool is_kprobe)
+{
+ struct symbol *sym = NULL;
+ struct map *map;
+ u64 addr;
+ int ret = -ENOENT;
+
+ if (!is_kprobe) {
+ map = dso__new_map(tp->module);
+ if (!map)
+ goto out;
+ addr = tp->address;
+ sym = map__find_symbol(map, addr, NULL);
+ } else {
+ addr = kernel_get_symbol_address_by_name(tp->symbol, true);
+ if (addr) {
+ addr += tp->offset;
+ sym = __find_kernel_function(addr, &map);
+ }
+ }
+ if (!sym)
+ goto out;
+
+ pp->retprobe = tp->retprobe;
+ pp->offset = addr - map->unmap_ip(map, sym->start);
+ pp->function = strdup(sym->name);
+ ret = pp->function ? 0 : -ENOMEM;
+
+out:
+ if (map && !is_kprobe) {
+ dso__delete(map->dso);
+ map__delete(map);
+ }
+
+ return ret;
+}
+
+static int convert_to_perf_probe_point(struct probe_trace_point *tp,
+ struct perf_probe_point *pp,
+ bool is_kprobe)
+{
+ char buf[128];
+ int ret;
+
+ ret = find_perf_probe_point_from_dwarf(tp, pp, is_kprobe);
+ if (!ret)
+ return 0;
+ ret = find_perf_probe_point_from_map(tp, pp, is_kprobe);
+ if (!ret)
+ return 0;
+
+ pr_debug("Failed to find probe point from both of dwarf and map.\n");
+
+ if (tp->symbol) {
+ pp->function = strdup(tp->symbol);
+ pp->offset = tp->offset;
+ } else if (!tp->module && !is_kprobe) {
+ ret = e_snprintf(buf, 128, "0x%" PRIx64, (u64)tp->address);
+ if (ret < 0)
+ return ret;
+ pp->function = strdup(buf);
+ pp->offset = 0;
+ }
+ if (pp->function == NULL)
+ return -ENOMEM;
+
+ pp->retprobe = tp->retprobe;
+
+ return 0;
+}
+
static int convert_to_perf_probe_event(struct probe_trace_event *tev,
struct perf_probe_event *pev, bool is_kprobe)
{
@@ -1636,11 +1701,7 @@ static int convert_to_perf_probe_event(struct probe_trace_event *tev,
return -ENOMEM;

/* Convert trace_point to probe_point */
- if (is_kprobe)
- ret = kprobe_convert_to_perf_probe(&tev->point, &pev->point);
- else
- ret = convert_to_perf_probe_point(&tev->point, &pev->point);
-
+ ret = convert_to_perf_probe_point(&tev->point, &pev->point, is_kprobe);
if (ret < 0)
return ret;


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