aboutsummaryrefslogtreecommitdiff
path: root/kernel/trace/trace_kdb.c
blob: 7b8ecd751d9395b4d07d22f347bf51dea457ffad (plain)
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
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
/*
 * kdb helper for dumping the ftrace buffer
 *
 * Copyright (C) 2010 Jason Wessel <jason.wessel@windriver.com>
 *
 * ftrace_dump_buf based on ftrace_dump:
 * Copyright (C) 2007-2008 Steven Rostedt <srostedt@redhat.com>
 * Copyright (C) 2008 Ingo Molnar <mingo@redhat.com>
 *
 */
#include <linux/init.h>
#include <linux/kgdb.h>
#include <linux/kdb.h>
#include <linux/ftrace.h>

#include "../debug/kdb/kdb_private.h"
#include "trace.h"
#include "trace_output.h"

static void ftrace_dump_buf(int skip_lines, long cpu_file)
{
	/* use static because iter can be a bit big for the stack */
	static struct trace_iterator iter;
	unsigned int old_userobj;
	int cnt = 0, cpu;

	trace_init_global_iter(&iter);

	for_each_tracing_cpu(cpu) {
		atomic_inc(&iter.tr->data[cpu]->disabled);
	}

	old_userobj = trace_flags;

	/* don't look at user memory in panic mode */
	trace_flags &= ~TRACE_ITER_SYM_USEROBJ;

	kdb_printf("Dumping ftrace buffer:\n");

	/* reset all but tr, trace, and overruns */
	memset(&iter.seq, 0,
		   sizeof(struct trace_iterator) -
		   offsetof(struct trace_iterator, seq));
	iter.iter_flags |= TRACE_FILE_LAT_FMT;
	iter.pos = -1;

	if (cpu_file == TRACE_PIPE_ALL_CPU) {
		for_each_tracing_cpu(cpu) {
			iter.buffer_iter[cpu] =
			ring_buffer_read_prepare(iter.tr->buffer, cpu);
			ring_buffer_read_start(iter.buffer_iter[cpu]);
			tracing_iter_reset(&iter, cpu);
		}
	} else {
		iter.cpu_file = cpu_file;
		iter.buffer_iter[cpu_file] =
			ring_buffer_read_prepare(iter.tr->buffer, cpu_file);
		ring_buffer_read_start(iter.buffer_iter[cpu_file]);
		tracing_iter_reset(&iter, cpu_file);
	}
	if (!trace_empty(&iter))
		trace_find_next_entry_inc(&iter);
	while (!trace_empty(&iter)) {
		if (!cnt)
			kdb_printf("---------------------------------\n");
		cnt++;

		if (trace_find_next_entry_inc(&iter) != NULL && !skip_lines)
			print_trace_line(&iter);
		if (!skip_lines)
			trace_printk_seq(&iter.seq);
		else
			skip_lines--;
		if (KDB_FLAG(CMD_INTERRUPT))
			goto out;
	}

	if (!cnt)
		kdb_printf("   (ftrace buffer empty)\n");
	else
		kdb_printf("---------------------------------\n");

out:
	trace_flags = old_userobj;

	for_each_tracing_cpu(cpu) {
		atomic_dec(&iter.tr->data[cpu]->disabled);
	}

	for_each_tracing_cpu(cpu)
		if (iter.buffer_iter[cpu])
			ring_buffer_read_finish(iter.buffer_iter[cpu]);
}

/*
 * kdb_ftdump - Dump the ftrace log buffer
 */
static int kdb_ftdump(int argc, const char **argv)
{
	int skip_lines = 0;
	long cpu_file;
	char *cp;

	if (argc > 2)
		return KDB_ARGCOUNT;

	if (argc) {
		skip_lines = simple_strtol(argv[1], &cp, 0);
		if (*cp)
			skip_lines = 0;
	}

	if (argc == 2) {
		cpu_file = simple_strtol(argv[2], &cp, 0);
		if (*cp || cpu_file >= NR_CPUS || cpu_file < 0 ||
		    !cpu_online(cpu_file))
			return KDB_BADINT;
	} else {
		cpu_file = TRACE_PIPE_ALL_CPU;
	}

	kdb_trap_printk++;
	ftrace_dump_buf(skip_lines, cpu_file);
	kdb_trap_printk--;

	return 0;
}

static __init int kdb_ftrace_register(void)
{
	kdb_register_repeat("ftdump", kdb_ftdump, "[skip_#lines] [cpu]",
			    "Dump ftrace log", 0, KDB_REPEAT_NONE);
	return 0;
}

late_initcall(kdb_ftrace_register);