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b2441318 | 1 | // SPDX-License-Identifier: GPL-2.0 |
955b61e5 JW |
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 | ||
955b61e5 JW |
17 | #include "trace.h" |
18 | #include "trace_output.h" | |
19 | ||
19063c77 | 20 | static void ftrace_dump_buf(int skip_lines, long cpu_file) |
955b61e5 JW |
21 | { |
22 | /* use static because iter can be a bit big for the stack */ | |
23 | static struct trace_iterator iter; | |
c270cc75 | 24 | static struct ring_buffer_iter *buffer_iter[CONFIG_NR_CPUS]; |
983f938a | 25 | struct trace_array *tr; |
955b61e5 JW |
26 | unsigned int old_userobj; |
27 | int cnt = 0, cpu; | |
28 | ||
29 | trace_init_global_iter(&iter); | |
c270cc75 | 30 | iter.buffer_iter = buffer_iter; |
983f938a | 31 | tr = iter.tr; |
955b61e5 JW |
32 | |
33 | for_each_tracing_cpu(cpu) { | |
12883efb | 34 | atomic_inc(&per_cpu_ptr(iter.trace_buffer->data, cpu)->disabled); |
955b61e5 JW |
35 | } |
36 | ||
983f938a | 37 | old_userobj = tr->trace_flags; |
955b61e5 JW |
38 | |
39 | /* don't look at user memory in panic mode */ | |
983f938a | 40 | tr->trace_flags &= ~TRACE_ITER_SYM_USEROBJ; |
955b61e5 JW |
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 | ||
ae3b5093 | 51 | if (cpu_file == RING_BUFFER_ALL_CPUS) { |
19063c77 JW |
52 | for_each_tracing_cpu(cpu) { |
53 | iter.buffer_iter[cpu] = | |
12883efb | 54 | ring_buffer_read_prepare(iter.trace_buffer->buffer, cpu); |
19063c77 JW |
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] = | |
12883efb | 61 | ring_buffer_read_prepare(iter.trace_buffer->buffer, cpu_file); |
19063c77 JW |
62 | ring_buffer_read_start(iter.buffer_iter[cpu_file]); |
63 | tracing_iter_reset(&iter, cpu_file); | |
955b61e5 | 64 | } |
8520dedb DT |
65 | |
66 | while (trace_find_next_entry_inc(&iter)) { | |
955b61e5 JW |
67 | if (!cnt) |
68 | kdb_printf("---------------------------------\n"); | |
69 | cnt++; | |
70 | ||
8520dedb | 71 | if (!skip_lines) { |
955b61e5 | 72 | print_trace_line(&iter); |
955b61e5 | 73 | trace_printk_seq(&iter.seq); |
8520dedb | 74 | } else { |
955b61e5 | 75 | skip_lines--; |
8520dedb DT |
76 | } |
77 | ||
955b61e5 JW |
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 | ||
87 | out: | |
983f938a | 88 | tr->trace_flags = old_userobj; |
955b61e5 JW |
89 | |
90 | for_each_tracing_cpu(cpu) { | |
12883efb | 91 | atomic_dec(&per_cpu_ptr(iter.trace_buffer->data, cpu)->disabled); |
955b61e5 JW |
92 | } |
93 | ||
c270cc75 DT |
94 | for_each_tracing_cpu(cpu) { |
95 | if (iter.buffer_iter[cpu]) { | |
955b61e5 | 96 | ring_buffer_read_finish(iter.buffer_iter[cpu]); |
c270cc75 DT |
97 | iter.buffer_iter[cpu] = NULL; |
98 | } | |
99 | } | |
955b61e5 JW |
100 | } |
101 | ||
102 | /* | |
103 | * kdb_ftdump - Dump the ftrace log buffer | |
104 | */ | |
105 | static int kdb_ftdump(int argc, const char **argv) | |
106 | { | |
107 | int skip_lines = 0; | |
19063c77 | 108 | long cpu_file; |
955b61e5 JW |
109 | char *cp; |
110 | ||
19063c77 | 111 | if (argc > 2) |
955b61e5 JW |
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 | ||
19063c77 JW |
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 { | |
ae3b5093 | 126 | cpu_file = RING_BUFFER_ALL_CPUS; |
19063c77 JW |
127 | } |
128 | ||
955b61e5 | 129 | kdb_trap_printk++; |
19063c77 | 130 | ftrace_dump_buf(skip_lines, cpu_file); |
955b61e5 JW |
131 | kdb_trap_printk--; |
132 | ||
133 | return 0; | |
134 | } | |
135 | ||
136 | static __init int kdb_ftrace_register(void) | |
137 | { | |
42c884c1 | 138 | kdb_register_flags("ftdump", kdb_ftdump, "[skip_#lines] [cpu]", |
9452e977 | 139 | "Dump ftrace log", 0, KDB_ENABLE_ALWAYS_SAFE); |
955b61e5 JW |
140 | return 0; |
141 | } | |
142 | ||
143 | late_initcall(kdb_ftrace_register); |