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1/*
2 * kdb helper for dumping the ftrace buffer
3 *
4 * Copyright (C) 2010 Jason Wessel <jason.wessel@windriver.com>
5 *
6 * ftrace_dump_buf based on ftrace_dump:
7 * Copyright (C) 2007-2008 Steven Rostedt <srostedt@redhat.com>
8 * Copyright (C) 2008 Ingo Molnar <mingo@redhat.com>
9 *
10 */
11#include <linux/init.h>
12#include <linux/kgdb.h>
13#include <linux/kdb.h>
14#include <linux/ftrace.h>
15
16#include "trace.h"
17#include "trace_output.h"
18
19static void ftrace_dump_buf(int skip_lines, long cpu_file)
20{
21 /* use static because iter can be a bit big for the stack */
22 static struct trace_iterator iter;
23 static struct ring_buffer_iter *buffer_iter[CONFIG_NR_CPUS];
24 struct trace_array *tr;
25 unsigned int old_userobj;
26 int cnt = 0, cpu;
27
28 trace_init_global_iter(&iter);
29 iter.buffer_iter = buffer_iter;
30 tr = iter.tr;
31
32 for_each_tracing_cpu(cpu) {
33 atomic_inc(&per_cpu_ptr(iter.trace_buffer->data, cpu)->disabled);
34 }
35
36 old_userobj = tr->trace_flags;
37
38 /* don't look at user memory in panic mode */
39 tr->trace_flags &= ~TRACE_ITER_SYM_USEROBJ;
40
41 kdb_printf("Dumping ftrace buffer:\n");
42
43 /* reset all but tr, trace, and overruns */
44 memset(&iter.seq, 0,
45 sizeof(struct trace_iterator) -
46 offsetof(struct trace_iterator, seq));
47 iter.iter_flags |= TRACE_FILE_LAT_FMT;
48 iter.pos = -1;
49
50 if (cpu_file == RING_BUFFER_ALL_CPUS) {
51 for_each_tracing_cpu(cpu) {
52 iter.buffer_iter[cpu] =
53 ring_buffer_read_prepare(iter.trace_buffer->buffer, cpu);
54 ring_buffer_read_start(iter.buffer_iter[cpu]);
55 tracing_iter_reset(&iter, cpu);
56 }
57 } else {
58 iter.cpu_file = cpu_file;
59 iter.buffer_iter[cpu_file] =
60 ring_buffer_read_prepare(iter.trace_buffer->buffer, cpu_file);
61 ring_buffer_read_start(iter.buffer_iter[cpu_file]);
62 tracing_iter_reset(&iter, cpu_file);
63 }
64
65 while (trace_find_next_entry_inc(&iter)) {
66 if (!cnt)
67 kdb_printf("---------------------------------\n");
68 cnt++;
69
70 if (!skip_lines) {
71 print_trace_line(&iter);
72 trace_printk_seq(&iter.seq);
73 } else {
74 skip_lines--;
75 }
76
77 if (KDB_FLAG(CMD_INTERRUPT))
78 goto out;
79 }
80
81 if (!cnt)
82 kdb_printf(" (ftrace buffer empty)\n");
83 else
84 kdb_printf("---------------------------------\n");
85
86out:
87 tr->trace_flags = old_userobj;
88
89 for_each_tracing_cpu(cpu) {
90 atomic_dec(&per_cpu_ptr(iter.trace_buffer->data, cpu)->disabled);
91 }
92
93 for_each_tracing_cpu(cpu) {
94 if (iter.buffer_iter[cpu]) {
95 ring_buffer_read_finish(iter.buffer_iter[cpu]);
96 iter.buffer_iter[cpu] = NULL;
97 }
98 }
99}
100
101/*
102 * kdb_ftdump - Dump the ftrace log buffer
103 */
104static int kdb_ftdump(int argc, const char **argv)
105{
106 int skip_lines = 0;
107 long cpu_file;
108 char *cp;
109
110 if (argc > 2)
111 return KDB_ARGCOUNT;
112
113 if (argc) {
114 skip_lines = simple_strtol(argv[1], &cp, 0);
115 if (*cp)
116 skip_lines = 0;
117 }
118
119 if (argc == 2) {
120 cpu_file = simple_strtol(argv[2], &cp, 0);
121 if (*cp || cpu_file >= NR_CPUS || cpu_file < 0 ||
122 !cpu_online(cpu_file))
123 return KDB_BADINT;
124 } else {
125 cpu_file = RING_BUFFER_ALL_CPUS;
126 }
127
128 kdb_trap_printk++;
129 ftrace_dump_buf(skip_lines, cpu_file);
130 kdb_trap_printk--;
131
132 return 0;
133}
134
135static __init int kdb_ftrace_register(void)
136{
137 kdb_register_flags("ftdump", kdb_ftdump, "[skip_#lines] [cpu]",
138 "Dump ftrace log", 0, KDB_ENABLE_ALWAYS_SAFE);
139 return 0;
140}
141
142late_initcall(kdb_ftrace_register);
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * kdb helper for dumping the ftrace buffer
4 *
5 * Copyright (C) 2010 Jason Wessel <jason.wessel@windriver.com>
6 *
7 * ftrace_dump_buf based on ftrace_dump:
8 * Copyright (C) 2007-2008 Steven Rostedt <srostedt@redhat.com>
9 * Copyright (C) 2008 Ingo Molnar <mingo@redhat.com>
10 *
11 */
12#include <linux/init.h>
13#include <linux/kgdb.h>
14#include <linux/kdb.h>
15#include <linux/ftrace.h>
16
17#include "trace.h"
18#include "trace_output.h"
19
20static struct trace_iterator iter;
21static struct ring_buffer_iter *buffer_iter[CONFIG_NR_CPUS];
22
23static void ftrace_dump_buf(int skip_entries, long cpu_file)
24{
25 struct trace_array *tr;
26 unsigned int old_userobj;
27 int cnt = 0, cpu;
28
29 tr = iter.tr;
30
31 old_userobj = tr->trace_flags;
32
33 /* don't look at user memory in panic mode */
34 tr->trace_flags &= ~TRACE_ITER_SYM_USEROBJ;
35
36 kdb_printf("Dumping ftrace buffer:\n");
37 if (skip_entries)
38 kdb_printf("(skipping %d entries)\n", skip_entries);
39
40 trace_iterator_reset(&iter);
41 iter.iter_flags |= TRACE_FILE_LAT_FMT;
42
43 if (cpu_file == RING_BUFFER_ALL_CPUS) {
44 for_each_tracing_cpu(cpu) {
45 iter.buffer_iter[cpu] =
46 ring_buffer_read_prepare(iter.array_buffer->buffer,
47 cpu, GFP_ATOMIC);
48 ring_buffer_read_start(iter.buffer_iter[cpu]);
49 tracing_iter_reset(&iter, cpu);
50 }
51 } else {
52 iter.cpu_file = cpu_file;
53 iter.buffer_iter[cpu_file] =
54 ring_buffer_read_prepare(iter.array_buffer->buffer,
55 cpu_file, GFP_ATOMIC);
56 ring_buffer_read_start(iter.buffer_iter[cpu_file]);
57 tracing_iter_reset(&iter, cpu_file);
58 }
59
60 while (trace_find_next_entry_inc(&iter)) {
61 if (!cnt)
62 kdb_printf("---------------------------------\n");
63 cnt++;
64
65 if (!skip_entries) {
66 print_trace_line(&iter);
67 trace_printk_seq(&iter.seq);
68 } else {
69 skip_entries--;
70 }
71
72 if (KDB_FLAG(CMD_INTERRUPT))
73 goto out;
74 }
75
76 if (!cnt)
77 kdb_printf(" (ftrace buffer empty)\n");
78 else
79 kdb_printf("---------------------------------\n");
80
81out:
82 tr->trace_flags = old_userobj;
83
84 for_each_tracing_cpu(cpu) {
85 if (iter.buffer_iter[cpu]) {
86 ring_buffer_read_finish(iter.buffer_iter[cpu]);
87 iter.buffer_iter[cpu] = NULL;
88 }
89 }
90}
91
92/*
93 * kdb_ftdump - Dump the ftrace log buffer
94 */
95static int kdb_ftdump(int argc, const char **argv)
96{
97 int skip_entries = 0;
98 long cpu_file;
99 int err;
100 int cnt;
101 int cpu;
102
103 if (argc > 2)
104 return KDB_ARGCOUNT;
105
106 if (argc && kstrtoint(argv[1], 0, &skip_entries))
107 return KDB_BADINT;
108
109 if (argc == 2) {
110 err = kstrtol(argv[2], 0, &cpu_file);
111 if (err || cpu_file >= NR_CPUS || cpu_file < 0 ||
112 !cpu_online(cpu_file))
113 return KDB_BADINT;
114 } else {
115 cpu_file = RING_BUFFER_ALL_CPUS;
116 }
117
118 kdb_trap_printk++;
119
120 trace_init_global_iter(&iter);
121 iter.buffer_iter = buffer_iter;
122
123 for_each_tracing_cpu(cpu) {
124 atomic_inc(&per_cpu_ptr(iter.array_buffer->data, cpu)->disabled);
125 }
126
127 /* A negative skip_entries means skip all but the last entries */
128 if (skip_entries < 0) {
129 if (cpu_file == RING_BUFFER_ALL_CPUS)
130 cnt = trace_total_entries(NULL);
131 else
132 cnt = trace_total_entries_cpu(NULL, cpu_file);
133 skip_entries = max(cnt + skip_entries, 0);
134 }
135
136 ftrace_dump_buf(skip_entries, cpu_file);
137
138 for_each_tracing_cpu(cpu) {
139 atomic_dec(&per_cpu_ptr(iter.array_buffer->data, cpu)->disabled);
140 }
141
142 kdb_trap_printk--;
143
144 return 0;
145}
146
147static kdbtab_t ftdump_cmd = {
148 .name = "ftdump",
149 .func = kdb_ftdump,
150 .usage = "[skip_#entries] [cpu]",
151 .help = "Dump ftrace log; -skip dumps last #entries",
152 .flags = KDB_ENABLE_ALWAYS_SAFE,
153};
154
155static __init int kdb_ftrace_register(void)
156{
157 kdb_register(&ftdump_cmd);
158 return 0;
159}
160
161late_initcall(kdb_ftrace_register);