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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 | ||
50bbae7d | 44 | trace_iterator_reset(&iter); |
955b61e5 | 45 | iter.iter_flags |= TRACE_FILE_LAT_FMT; |
955b61e5 | 46 | |
ae3b5093 | 47 | if (cpu_file == RING_BUFFER_ALL_CPUS) { |
19063c77 JW |
48 | for_each_tracing_cpu(cpu) { |
49 | iter.buffer_iter[cpu] = | |
2d412eb3 DA |
50 | ring_buffer_read_prepare(iter.trace_buffer->buffer, |
51 | cpu, GFP_ATOMIC); | |
19063c77 JW |
52 | ring_buffer_read_start(iter.buffer_iter[cpu]); |
53 | tracing_iter_reset(&iter, cpu); | |
54 | } | |
55 | } else { | |
56 | iter.cpu_file = cpu_file; | |
57 | iter.buffer_iter[cpu_file] = | |
2d412eb3 DA |
58 | ring_buffer_read_prepare(iter.trace_buffer->buffer, |
59 | cpu_file, GFP_ATOMIC); | |
19063c77 JW |
60 | ring_buffer_read_start(iter.buffer_iter[cpu_file]); |
61 | tracing_iter_reset(&iter, cpu_file); | |
955b61e5 | 62 | } |
8520dedb DT |
63 | |
64 | while (trace_find_next_entry_inc(&iter)) { | |
955b61e5 JW |
65 | if (!cnt) |
66 | kdb_printf("---------------------------------\n"); | |
67 | cnt++; | |
68 | ||
8520dedb | 69 | if (!skip_lines) { |
955b61e5 | 70 | print_trace_line(&iter); |
955b61e5 | 71 | trace_printk_seq(&iter.seq); |
8520dedb | 72 | } else { |
955b61e5 | 73 | skip_lines--; |
8520dedb DT |
74 | } |
75 | ||
955b61e5 JW |
76 | if (KDB_FLAG(CMD_INTERRUPT)) |
77 | goto out; | |
78 | } | |
79 | ||
80 | if (!cnt) | |
81 | kdb_printf(" (ftrace buffer empty)\n"); | |
82 | else | |
83 | kdb_printf("---------------------------------\n"); | |
84 | ||
85 | out: | |
983f938a | 86 | tr->trace_flags = old_userobj; |
955b61e5 JW |
87 | |
88 | for_each_tracing_cpu(cpu) { | |
12883efb | 89 | atomic_dec(&per_cpu_ptr(iter.trace_buffer->data, cpu)->disabled); |
955b61e5 JW |
90 | } |
91 | ||
c270cc75 DT |
92 | for_each_tracing_cpu(cpu) { |
93 | if (iter.buffer_iter[cpu]) { | |
955b61e5 | 94 | ring_buffer_read_finish(iter.buffer_iter[cpu]); |
c270cc75 DT |
95 | iter.buffer_iter[cpu] = NULL; |
96 | } | |
97 | } | |
955b61e5 JW |
98 | } |
99 | ||
100 | /* | |
101 | * kdb_ftdump - Dump the ftrace log buffer | |
102 | */ | |
103 | static int kdb_ftdump(int argc, const char **argv) | |
104 | { | |
105 | int skip_lines = 0; | |
19063c77 | 106 | long cpu_file; |
955b61e5 JW |
107 | char *cp; |
108 | ||
19063c77 | 109 | if (argc > 2) |
955b61e5 JW |
110 | return KDB_ARGCOUNT; |
111 | ||
112 | if (argc) { | |
113 | skip_lines = simple_strtol(argv[1], &cp, 0); | |
114 | if (*cp) | |
115 | skip_lines = 0; | |
116 | } | |
117 | ||
19063c77 JW |
118 | if (argc == 2) { |
119 | cpu_file = simple_strtol(argv[2], &cp, 0); | |
120 | if (*cp || cpu_file >= NR_CPUS || cpu_file < 0 || | |
121 | !cpu_online(cpu_file)) | |
122 | return KDB_BADINT; | |
123 | } else { | |
ae3b5093 | 124 | cpu_file = RING_BUFFER_ALL_CPUS; |
19063c77 JW |
125 | } |
126 | ||
955b61e5 | 127 | kdb_trap_printk++; |
19063c77 | 128 | ftrace_dump_buf(skip_lines, cpu_file); |
955b61e5 JW |
129 | kdb_trap_printk--; |
130 | ||
131 | return 0; | |
132 | } | |
133 | ||
134 | static __init int kdb_ftrace_register(void) | |
135 | { | |
42c884c1 | 136 | kdb_register_flags("ftdump", kdb_ftdump, "[skip_#lines] [cpu]", |
9452e977 | 137 | "Dump ftrace log", 0, KDB_ENABLE_ALWAYS_SAFE); |
955b61e5 JW |
138 | return 0; |
139 | } | |
140 | ||
141 | late_initcall(kdb_ftrace_register); |