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Date: Tue, 03 Sep 2013 13:07:03 +0530
From: Hemant Kumar <hkshaw@...ux.vnet.ibm.com>
To: linux-kernel@...r.kernel.org
Cc: srikar@...ux.vnet.ibm.com, peterz@...radead.org, oleg@...hat.com,
mingo@...hat.com, anton@...hat.com, systemtap@...rceware.org,
masami.hiramatsu.pt@...achi.com
Subject: [PATCH 2/2] Support to perf to probe on SDT markers:
This patch enables perf to probe on the marker name specified on the command line.
---
tools/perf/builtin-probe.c | 7 +++
tools/perf/util/probe-event.c | 11 ++++
tools/perf/util/symbol-elf.c | 112 +++++++++++++++++++++++++++++++++++++++++
tools/perf/util/symbol.h | 5 ++
4 files changed, 135 insertions(+)
diff --git a/tools/perf/builtin-probe.c b/tools/perf/builtin-probe.c
index 3d8dcdf..8382853 100644
--- a/tools/perf/builtin-probe.c
+++ b/tools/perf/builtin-probe.c
@@ -378,6 +378,13 @@ int cmd_probe(int argc, const char **argv, const char *prefix __maybe_unused)
" (%d)\n", ret);
return ret;
}
+ params.uprobes = true;
+ ret = probe_marker(params.target,
+ params.events[0].point.function);
+ if (ret < 0)
+ pr_err("Could not probe at %s marker\n",
+ params.events[0].point.function);
+ return ret;
}
if (params.list_events) {
diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
index 7f846f9..014d642 100644
--- a/tools/perf/util/probe-event.c
+++ b/tools/perf/util/probe-event.c
@@ -2378,3 +2378,14 @@ int show_available_markers(const char *target)
setup_pager();
return list_markers(target);
}
+
+int probe_marker(const char *name, char *mark)
+{
+ int fd;
+
+ fd = open_uprobe_events(true);
+ if (fd == -1)
+ return fd;
+ else
+ return probe__marker(name, mark, fd);
+}
diff --git a/tools/perf/util/symbol-elf.c b/tools/perf/util/symbol-elf.c
index f3630f2..60938a5 100644
--- a/tools/perf/util/symbol-elf.c
+++ b/tools/perf/util/symbol-elf.c
@@ -1040,6 +1040,118 @@ out_ret:
return ret;
}
+static void extract_first_name(const char *target, char *fname)
+{
+ int i, len;
+ char *file;
+
+ file = strrchr(target, DIR_SEP);
+ file++;
+ len = strlen(file);
+ for (i = 0; i <= len; i++) {
+ if (!isalpha(file[i]))
+ break;
+ fname[i] = file[i];
+ }
+ fname[i] = '\0';
+}
+
+static int probe_at_note(struct sdt_note *r_note, const char *target, bool exec,
+ int fd)
+{
+ char buf[MAX_CMDLEN];
+ int len, err = -1;
+ Elf64_Addr offset;
+ char *fname = NULL;
+
+ if (exec)
+ offset = r_note->addr.a64[0] - TEXT_SCN;
+ else
+ offset = r_note->addr.a64[0];
+
+ fname = (char *)zalloc(sizeof(char) * strlen(target));
+ if (fname == NULL) {
+ pr_err("Error in allocating memory to fname\n");
+ goto out_ret;
+ }
+
+ extract_first_name(target, fname);
+ len = snprintf(buf, MAX_CMDLEN, "%c:%s%s/%s %s:0x%x", 'p', "probe_",
+ fname, r_note->name, target, (unsigned)offset);
+
+ len = write(fd, buf, MAX_CMDLEN);
+ if (len < 0) {
+ pr_err("Couldn't write into uprobe_events!\n");
+ goto out_close;
+ } else {
+ printf("Added new event :\n");
+ printf("event = %s \t (on 0x%x)\n\n", r_note->name,
+ (unsigned)offset);
+ printf("You can now use it on all perf tools such as :\n\n");
+ printf("\t perf record -e %s%s:%s -aR sleep 1\n\n", "probe_", fname, r_note->name);
+ err = 0;
+ }
+
+out_close:
+ close(fd);
+ free(fname);
+out_ret:
+ return err;
+}
+
+static int search_and_probe_at_note(char *key, struct sdt_note **start,
+ const char *target, bool exec, int fd)
+{
+ int ret = -1;
+ struct sdt_note *req;
+
+ for (req = (*start); req != NULL; req = req->next) {
+ if (!strcmp(key, req->name))
+ break;
+ }
+ if (!req) {
+ pr_err("Could not find marker %s\n", key);
+ return ret;
+ }
+
+ ret = probe_at_note(req, target, exec, fd);
+ return ret;
+}
+
+int probe__marker(const char *name, char *mark, int evfd)
+{
+ int ret = -1, fd;
+ Elf *elf;
+ bool exec = false;
+ struct sdt_note *head = NULL;
+
+ fd = open(name, O_RDONLY);
+ if (fd < 0) {
+ pr_err("Failed to open the file\n");
+ goto out_ret;
+ }
+
+ symbol__elf_init();
+ elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL);
+ if (elf == NULL) {
+ pr_debug("%s: cannot read %s ELF file.\n", __func__, name);
+ goto out_close;
+ }
+
+ head = get_elf_markers(elf, &exec, true);
+ if (head) {
+ ret = search_and_probe_at_note(mark, &head, name, exec, evfd);
+ cleanup_notes(head);
+ }
+
+ elf_end(elf);
+
+out_close:
+ close(fd);
+out_ret:
+ return ret;
+}
+
void cleanup_notes(struct sdt_note *start)
{
struct sdt_note *tmp;
diff --git a/tools/perf/util/symbol.h b/tools/perf/util/symbol.h
index f2d17b7..95289fd 100644
--- a/tools/perf/util/symbol.h
+++ b/tools/perf/util/symbol.h
@@ -262,8 +262,13 @@ void __map_groups__fixup_end(struct map_groups *mg, enum map_type type);
int show_available_markers(const char *module);
int list_markers(const char *name);
void cleanup_notes(struct sdt_note *start);
+int probe_marker(const char *name, char *mark);
+int probe__marker(const char *name, char *mark, int fd);
#define SDT_NOTE_TYPE 3
#define NOTE_SCN ".note.stapsdt"
+#define TEXT_SCN 0x400000
+#define DIR_SEP '/'
+#define MAX_CMDLEN 256
#endif /* __PERF_SYMBOL */
--
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