Home Home > GIT Browse
summaryrefslogtreecommitdiff
blob: cca65044c14c03b45b62ee44c0498cbc06f01458 (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
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
// SPDX-License-Identifier: GPL-2.0
/*
 * 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 "trace.h"
#include "trace_output.h"

static struct trace_iterator iter;
static struct ring_buffer_iter *buffer_iter[CONFIG_NR_CPUS];

static void ftrace_dump_buf(int skip_entries, long cpu_file)
{
	struct trace_array *tr;
	unsigned int old_userobj;
	int cnt = 0, cpu;

	tr = iter.tr;

	old_userobj = tr->trace_flags;

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

	kdb_printf("Dumping ftrace buffer:\n");
	if (skip_entries)
		kdb_printf("(skipping %d entries)\n", skip_entries);

	trace_iterator_reset(&iter);
	iter.iter_flags |= TRACE_FILE_LAT_FMT;

	if (cpu_file == RING_BUFFER_ALL_CPUS) {
		for_each_tracing_cpu(cpu) {
			iter.buffer_iter[cpu] =
			ring_buffer_read_prepare(iter.trace_buffer->buffer,
						 cpu, GFP_ATOMIC);
			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.trace_buffer->buffer,
						 cpu_file, GFP_ATOMIC);
		ring_buffer_read_start(iter.buffer_iter[cpu_file]);
		tracing_iter_reset(&iter, cpu_file);
	}

	while (trace_find_next_entry_inc(&iter)) {
		if (!cnt)
			kdb_printf("---------------------------------\n");
		cnt++;

		if (!skip_entries) {
			print_trace_line(&iter);
			trace_printk_seq(&iter.seq);
		} else {
			skip_entries--;
		}

		if (KDB_FLAG(CMD_INTERRUPT))
			goto out;
	}

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

out:
	tr->trace_flags = old_userobj;

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

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

	if (argc > 2)
		return KDB_ARGCOUNT;

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

	kdb_trap_printk++;

	trace_init_global_iter(&iter);
	iter.buffer_iter = buffer_iter;

	for_each_tracing_cpu(cpu) {
		atomic_inc(&per_cpu_ptr(iter.trace_buffer->data, cpu)->disabled);
	}

	/* A negative skip_entries means skip all but the last entries */
	if (skip_entries < 0) {
		if (cpu_file == RING_BUFFER_ALL_CPUS)
			cnt = trace_total_entries(NULL);
		else
			cnt = trace_total_entries_cpu(NULL, cpu_file);
		skip_entries = max(cnt + skip_entries, 0);
	}

	ftrace_dump_buf(skip_entries, cpu_file);

	for_each_tracing_cpu(cpu) {
		atomic_dec(&per_cpu_ptr(iter.trace_buffer->data, cpu)->disabled);
	}

	kdb_trap_printk--;

	return 0;
}

static __init int kdb_ftrace_register(void)
{
	kdb_register_flags("ftdump", kdb_ftdump, "[skip_#entries] [cpu]",
			    "Dump ftrace log; -skip dumps last #entries", 0,
			    KDB_ENABLE_ALWAYS_SAFE);
	return 0;
}

late_initcall(kdb_ftrace_register);