1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
|
/*
*
* Function return tracer.
* Copyright (c) 2008 Frederic Weisbecker <fweisbec@gmail.com>
* Mostly borrowed from function tracer which
* is Copyright (c) Steven Rostedt <srostedt@redhat.com>
*
*/
#include <linux/debugfs.h>
#include <linux/uaccess.h>
#include <linux/ftrace.h>
#include <linux/fs.h>
#include "trace.h"
#define TRACE_RETURN_PRINT_OVERRUN 0x1
static struct tracer_opt trace_opts[] = {
/* Display overruns or not */
{ TRACER_OPT(overrun, TRACE_RETURN_PRINT_OVERRUN) },
{ } /* Empty entry */
};
static struct tracer_flags tracer_flags = {
.val = 0, /* Don't display overruns by default */
.opts = trace_opts
};
static int return_trace_init(struct trace_array *tr)
{
int cpu;
for_each_online_cpu(cpu)
tracing_reset(tr, cpu);
return register_ftrace_return(&trace_function_return);
}
static void return_trace_reset(struct trace_array *tr)
{
unregister_ftrace_return();
}
enum print_line_t
print_return_function(struct trace_iterator *iter)
{
struct trace_seq *s = &iter->seq;
struct trace_entry *entry = iter->ent;
struct ftrace_ret_entry *field;
int ret;
if (entry->type == TRACE_FN_RET) {
trace_assign_type(field, entry);
ret = trace_seq_printf(s, "%pF -> ", (void *)field->parent_ip);
if (!ret)
return TRACE_TYPE_PARTIAL_LINE;
ret = seq_print_ip_sym(s, field->ip,
trace_flags & TRACE_ITER_SYM_MASK);
if (!ret)
return TRACE_TYPE_PARTIAL_LINE;
ret = trace_seq_printf(s, " (%llu ns)",
field->rettime - field->calltime);
if (!ret)
return TRACE_TYPE_PARTIAL_LINE;
if (tracer_flags.val & TRACE_RETURN_PRINT_OVERRUN) {
ret = trace_seq_printf(s, " (Overruns: %lu)",
field->overrun);
if (!ret)
return TRACE_TYPE_PARTIAL_LINE;
}
ret = trace_seq_printf(s, "\n");
if (!ret)
return TRACE_TYPE_PARTIAL_LINE;
return TRACE_TYPE_HANDLED;
}
return TRACE_TYPE_UNHANDLED;
}
static struct tracer return_trace __read_mostly = {
.name = "return",
.init = return_trace_init,
.reset = return_trace_reset,
.print_line = print_return_function,
.flags = &tracer_flags,
};
static __init int init_return_trace(void)
{
return register_tracer(&return_trace);
}
device_initcall(init_return_trace);
|
