| Jason Wessel | 955b61e | 2010-08-05 09:22:23 -0500 | [diff] [blame^] | 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 "../debug/kdb/kdb_private.h" |
| 17 | #include "trace.h" |
| 18 | #include "trace_output.h" |
| 19 | |
| 20 | static void ftrace_dump_buf(int skip_lines) |
| 21 | { |
| 22 | /* use static because iter can be a bit big for the stack */ |
| 23 | static struct trace_iterator iter; |
| 24 | unsigned int old_userobj; |
| 25 | int cnt = 0, cpu; |
| 26 | |
| 27 | trace_init_global_iter(&iter); |
| 28 | |
| 29 | for_each_tracing_cpu(cpu) { |
| 30 | atomic_inc(&iter.tr->data[cpu]->disabled); |
| 31 | } |
| 32 | |
| 33 | old_userobj = trace_flags; |
| 34 | |
| 35 | /* don't look at user memory in panic mode */ |
| 36 | trace_flags &= ~TRACE_ITER_SYM_USEROBJ; |
| 37 | |
| 38 | kdb_printf("Dumping ftrace buffer:\n"); |
| 39 | |
| 40 | /* reset all but tr, trace, and overruns */ |
| 41 | memset(&iter.seq, 0, |
| 42 | sizeof(struct trace_iterator) - |
| 43 | offsetof(struct trace_iterator, seq)); |
| 44 | iter.iter_flags |= TRACE_FILE_LAT_FMT; |
| 45 | iter.pos = -1; |
| 46 | |
| 47 | for_each_tracing_cpu(cpu) { |
| 48 | iter.buffer_iter[cpu] = |
| 49 | ring_buffer_read_prepare(iter.tr->buffer, cpu); |
| 50 | ring_buffer_read_start(iter.buffer_iter[cpu]); |
| 51 | tracing_iter_reset(&iter, cpu); |
| 52 | } |
| 53 | |
| 54 | if (!trace_empty(&iter)) |
| 55 | trace_find_next_entry_inc(&iter); |
| 56 | while (!trace_empty(&iter)) { |
| 57 | if (!cnt) |
| 58 | kdb_printf("---------------------------------\n"); |
| 59 | cnt++; |
| 60 | |
| 61 | if (trace_find_next_entry_inc(&iter) != NULL && !skip_lines) |
| 62 | print_trace_line(&iter); |
| 63 | if (!skip_lines) |
| 64 | trace_printk_seq(&iter.seq); |
| 65 | else |
| 66 | skip_lines--; |
| 67 | if (KDB_FLAG(CMD_INTERRUPT)) |
| 68 | goto out; |
| 69 | } |
| 70 | |
| 71 | if (!cnt) |
| 72 | kdb_printf(" (ftrace buffer empty)\n"); |
| 73 | else |
| 74 | kdb_printf("---------------------------------\n"); |
| 75 | |
| 76 | out: |
| 77 | trace_flags = old_userobj; |
| 78 | |
| 79 | for_each_tracing_cpu(cpu) { |
| 80 | atomic_dec(&iter.tr->data[cpu]->disabled); |
| 81 | } |
| 82 | |
| 83 | for_each_tracing_cpu(cpu) |
| 84 | if (iter.buffer_iter[cpu]) |
| 85 | ring_buffer_read_finish(iter.buffer_iter[cpu]); |
| 86 | } |
| 87 | |
| 88 | /* |
| 89 | * kdb_ftdump - Dump the ftrace log buffer |
| 90 | */ |
| 91 | static int kdb_ftdump(int argc, const char **argv) |
| 92 | { |
| 93 | int skip_lines = 0; |
| 94 | char *cp; |
| 95 | |
| 96 | if (argc > 1) |
| 97 | return KDB_ARGCOUNT; |
| 98 | |
| 99 | if (argc) { |
| 100 | skip_lines = simple_strtol(argv[1], &cp, 0); |
| 101 | if (*cp) |
| 102 | skip_lines = 0; |
| 103 | } |
| 104 | |
| 105 | kdb_trap_printk++; |
| 106 | ftrace_dump_buf(skip_lines); |
| 107 | kdb_trap_printk--; |
| 108 | |
| 109 | return 0; |
| 110 | } |
| 111 | |
| 112 | static __init int kdb_ftrace_register(void) |
| 113 | { |
| 114 | kdb_register_repeat("ftdump", kdb_ftdump, "", "Dump ftrace log", |
| 115 | 0, KDB_REPEAT_NONE); |
| 116 | return 0; |
| 117 | } |
| 118 | |
| 119 | late_initcall(kdb_ftrace_register); |