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Subject[PATCH 08/10] trace_kprobe: init print_fmt
Init print_fmt for trace_kprobe.
It will be used for replacing ->show_format().

Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
---
diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index 3ef66d4..a12d39b 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -1212,6 +1212,55 @@ static int kretprobe_event_show_format(struct ftrace_event_call *call,
", REC->" FIELD_STRING_RETIP);
}

+static int __set_print_fmt(struct trace_probe *tp, char *buf, int len)
+{
+ int i;
+ int pos = 0;
+
+ const char *fmt, *arg;
+
+ if (!probe_is_return(tp)) {
+ fmt = "(%lx)";
+ arg = "REC->" FIELD_STRING_IP;
+ } else {
+ fmt = "(%lx <- %lx)";
+ arg = "REC->" FIELD_STRING_FUNC ", REC->" FIELD_STRING_RETIP;
+ }
+
+ pos += snprintf(buf + pos, len > pos ? len - pos : 0, "\"%s", fmt);
+
+ for (i = 0; i < tp->nr_args; i++) {
+ pos += snprintf(buf + pos, len > pos ? len - pos : 0,
+ " %s=%%lx", tp->args[i].name);
+ }
+
+ pos += snprintf(buf + pos, len > pos ? len - pos : 0, "\", %s", arg);
+
+ for (i = 0; i < tp->nr_args; i++) {
+ pos += snprintf(buf + pos, len > pos ? len - pos : 0,
+ ", REC->%s", tp->args[i].name);
+ }
+
+ /* return the length of print_fmt */
+ return pos;
+}
+
+static int set_print_fmt(struct trace_probe *tp)
+{
+ int len;
+ char *print_fmt;
+
+ len = __set_print_fmt(tp, NULL, 0);
+ print_fmt = kmalloc(len + 1, GFP_KERNEL);
+ if (!print_fmt)
+ return -ENOMEM;
+
+ __set_print_fmt(tp, print_fmt, len + 1);
+ tp->call.print_fmt = print_fmt;
+
+ return 0;
+}
+
#ifdef CONFIG_EVENT_PROFILE

/* Kprobe profile handler */
@@ -1418,10 +1467,14 @@ static int register_probe_event(struct trace_probe *tp)
call->show_format = kprobe_event_show_format;
call->define_fields = kprobe_event_define_fields;
}
+ if (set_print_fmt(tp) < 0)
+ return -ENOMEM;
call->event = &tp->event;
call->id = register_ftrace_event(&tp->event);
- if (!call->id)
+ if (!call->id) {
+ kfree(call->print_fmt);
return -ENODEV;
+ }
call->enabled = 0;
call->regfunc = probe_event_enable;
call->unregfunc = probe_event_disable;
@@ -1435,6 +1488,7 @@ static int register_probe_event(struct trace_probe *tp)
ret = trace_add_event_call(call);
if (ret) {
pr_info("Failed to register kprobe event: %s\n", call->name);
+ kfree(call->print_fmt);
unregister_ftrace_event(&tp->event);
}
return ret;
@@ -1444,6 +1498,7 @@ static void unregister_probe_event(struct trace_probe *tp)
{
/* tp->event is unregistered in trace_remove_event_call() */
trace_remove_event_call(&tp->call);
+ kfree(tp->call.print_fmt);
}

/* Make a debugfs interface for controling probe points */


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