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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 void ftrace_dump_buf(int skip_lines, long cpu_file)
21{
22 /* use static because iter can be a bit big for the stack */
23 static struct trace_iterator iter;
24 static struct ring_buffer_iter *buffer_iter[CONFIG_NR_CPUS];
25 struct trace_array *tr;
26 unsigned int old_userobj;
27 int cnt = 0, cpu;
28
29 trace_init_global_iter(&iter);
30 iter.buffer_iter = buffer_iter;
31 tr = iter.tr;
32
33 for_each_tracing_cpu(cpu) {
34 atomic_inc(&per_cpu_ptr(iter.trace_buffer->data, cpu)->disabled);
35 }
36
37 old_userobj = tr->trace_flags;
38
39 /* don't look at user memory in panic mode */
40 tr->trace_flags &= ~TRACE_ITER_SYM_USEROBJ;
41
42 kdb_printf("Dumping ftrace buffer:\n");
43
44 /* reset all but tr, trace, and overruns */
45 memset(&iter.seq, 0,
46 sizeof(struct trace_iterator) -
47 offsetof(struct trace_iterator, seq));
48 iter.iter_flags |= TRACE_FILE_LAT_FMT;
49 iter.pos = -1;
50
51 if (cpu_file == RING_BUFFER_ALL_CPUS) {
52 for_each_tracing_cpu(cpu) {
53 iter.buffer_iter[cpu] =
54 ring_buffer_read_prepare(iter.trace_buffer->buffer, cpu);
55 ring_buffer_read_start(iter.buffer_iter[cpu]);
56 tracing_iter_reset(&iter, cpu);
57 }
58 } else {
59 iter.cpu_file = cpu_file;
60 iter.buffer_iter[cpu_file] =
61 ring_buffer_read_prepare(iter.trace_buffer->buffer, cpu_file);
62 ring_buffer_read_start(iter.buffer_iter[cpu_file]);
63 tracing_iter_reset(&iter, cpu_file);
64 }
65
66 while (trace_find_next_entry_inc(&iter)) {
67 if (!cnt)
68 kdb_printf("---------------------------------\n");
69 cnt++;
70
71 if (!skip_lines) {
72 print_trace_line(&iter);
73 trace_printk_seq(&iter.seq);
74 } else {
75 skip_lines--;
76 }
77
78 if (KDB_FLAG(CMD_INTERRUPT))
79 goto out;
80 }
81
82 if (!cnt)
83 kdb_printf(" (ftrace buffer empty)\n");
84 else
85 kdb_printf("---------------------------------\n");
86
87out:
88 tr->trace_flags = old_userobj;
89
90 for_each_tracing_cpu(cpu) {
91 atomic_dec(&per_cpu_ptr(iter.trace_buffer->data, cpu)->disabled);
92 }
93
94 for_each_tracing_cpu(cpu) {
95 if (iter.buffer_iter[cpu]) {
96 ring_buffer_read_finish(iter.buffer_iter[cpu]);
97 iter.buffer_iter[cpu] = NULL;
98 }
99 }
100}
101
102/*
103 * kdb_ftdump - Dump the ftrace log buffer
104 */
105static int kdb_ftdump(int argc, const char **argv)
106{
107 int skip_lines = 0;
108 long cpu_file;
109 char *cp;
110
111 if (argc > 2)
112 return KDB_ARGCOUNT;
113
114 if (argc) {
115 skip_lines = simple_strtol(argv[1], &cp, 0);
116 if (*cp)
117 skip_lines = 0;
118 }
119
120 if (argc == 2) {
121 cpu_file = simple_strtol(argv[2], &cp, 0);
122 if (*cp || cpu_file >= NR_CPUS || cpu_file < 0 ||
123 !cpu_online(cpu_file))
124 return KDB_BADINT;
125 } else {
126 cpu_file = RING_BUFFER_ALL_CPUS;
127 }
128
129 kdb_trap_printk++;
130 ftrace_dump_buf(skip_lines, cpu_file);
131 kdb_trap_printk--;
132
133 return 0;
134}
135
136static __init int kdb_ftrace_register(void)
137{
138 kdb_register_flags("ftdump", kdb_ftdump, "[skip_#lines] [cpu]",
139 "Dump ftrace log", 0, KDB_ENABLE_ALWAYS_SAFE);
140 return 0;
141}
142
143late_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 char *cp;
100 int cnt;
101 int cpu;
102
103 if (argc > 2)
104 return KDB_ARGCOUNT;
105
106 if (argc) {
107 skip_entries = simple_strtol(argv[1], &cp, 0);
108 if (*cp)
109 skip_entries = 0;
110 }
111
112 if (argc == 2) {
113 cpu_file = simple_strtol(argv[2], &cp, 0);
114 if (*cp || cpu_file >= NR_CPUS || cpu_file < 0 ||
115 !cpu_online(cpu_file))
116 return KDB_BADINT;
117 } else {
118 cpu_file = RING_BUFFER_ALL_CPUS;
119 }
120
121 kdb_trap_printk++;
122
123 trace_init_global_iter(&iter);
124 iter.buffer_iter = buffer_iter;
125
126 for_each_tracing_cpu(cpu) {
127 atomic_inc(&per_cpu_ptr(iter.array_buffer->data, cpu)->disabled);
128 }
129
130 /* A negative skip_entries means skip all but the last entries */
131 if (skip_entries < 0) {
132 if (cpu_file == RING_BUFFER_ALL_CPUS)
133 cnt = trace_total_entries(NULL);
134 else
135 cnt = trace_total_entries_cpu(NULL, cpu_file);
136 skip_entries = max(cnt + skip_entries, 0);
137 }
138
139 ftrace_dump_buf(skip_entries, cpu_file);
140
141 for_each_tracing_cpu(cpu) {
142 atomic_dec(&per_cpu_ptr(iter.array_buffer->data, cpu)->disabled);
143 }
144
145 kdb_trap_printk--;
146
147 return 0;
148}
149
150static kdbtab_t ftdump_cmd = {
151 .name = "ftdump",
152 .func = kdb_ftdump,
153 .usage = "[skip_#entries] [cpu]",
154 .help = "Dump ftrace log; -skip dumps last #entries",
155 .flags = KDB_ENABLE_ALWAYS_SAFE,
156};
157
158static __init int kdb_ftrace_register(void)
159{
160 kdb_register(&ftdump_cmd);
161 return 0;
162}
163
164late_initcall(kdb_ftrace_register);