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tracing/kprobes: Init print_fmt for kprobe events

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This is part of a patch set that removes the show_format method
in the ftrace event macros.

Add the print_fmt initialization to the kprobe events.
The print_fmt is still not used, but will be in the follow up
patches.

Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
LKML-Reference: <4B273D45.3080100@cn.fujitsu.com>
Acked-by: Masami Hiramatsu <mhiramat@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
This commit is contained in:
Lai Jiangshan 2009-12-15 15:39:49 +08:00 committed by Steven Rostedt
parent 50307a45f8
commit a342a0280b
1 changed files with 63 additions and 1 deletions
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64
kernel/trace/trace_kprobe.c
View File

@ -1250,6 +1250,62 @@ 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;
}
/* When len=0, we just calculate the needed length */
#define LEN_OR_ZERO (len ? len - pos : 0)
pos += snprintf(buf + pos, LEN_OR_ZERO, "\"%s", fmt);
for (i = 0; i < tp->nr_args; i++) {
pos += snprintf(buf + pos, LEN_OR_ZERO, " %s=%%lx",
tp->args[i].name);
}
pos += snprintf(buf + pos, LEN_OR_ZERO, "\", %s", arg);
for (i = 0; i < tp->nr_args; i++) {
pos += snprintf(buf + pos, LEN_OR_ZERO, ", REC->%s",
tp->args[i].name);
}
#undef LEN_OR_ZERO
/* return the length of print_fmt */
return pos;
}
static int set_print_fmt(struct trace_probe *tp)
{
int len;
char *print_fmt;
/* First: called with 0 length to calculate the needed length */
len = __set_print_fmt(tp, NULL, 0);
print_fmt = kmalloc(len + 1, GFP_KERNEL);
if (!print_fmt)
return -ENOMEM;
/* Second: actually write the @print_fmt */
__set_print_fmt(tp, print_fmt, len + 1);
tp->call.print_fmt = print_fmt;
return 0;
}
#ifdef CONFIG_EVENT_PROFILE
/* Kprobe profile handler */
@ -1456,10 +1512,14 @@ 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;
@ -1472,6 +1532,7 @@ 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;
@ -1481,6 +1542,7 @@ 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 */