From 955b61e597984745fb7d34c75708f6503b6aaeab Mon Sep 17 00:00:00 2001 From: Jason Wessel Date: Thu, 5 Aug 2010 09:22:23 -0500 Subject: ftrace,kdb: Extend kdb to be able to dump the ftrace buffer Add in a helper function to allow the kdb shell to dump the ftrace buffer. Modify trace.c to expose the capability to iterate over the ftrace buffer in a read only capacity. Signed-off-by: Jason Wessel Acked-by: Steven Rostedt CC: Frederic Weisbecker --- kernel/trace/trace_kdb.c | 119 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 119 insertions(+) create mode 100644 kernel/trace/trace_kdb.c (limited to 'kernel/trace/trace_kdb.c') diff --git a/kernel/trace/trace_kdb.c b/kernel/trace/trace_kdb.c new file mode 100644 index 000000000000..44cbda25b0a5 --- /dev/null +++ b/kernel/trace/trace_kdb.c @@ -0,0 +1,119 @@ +/* + * kdb helper for dumping the ftrace buffer + * + * Copyright (C) 2010 Jason Wessel + * + * ftrace_dump_buf based on ftrace_dump: + * Copyright (C) 2007-2008 Steven Rostedt + * Copyright (C) 2008 Ingo Molnar + * + */ +#include +#include +#include +#include + +#include "../debug/kdb/kdb_private.h" +#include "trace.h" +#include "trace_output.h" + +static void ftrace_dump_buf(int skip_lines) +{ + /* use static because iter can be a bit big for the stack */ + static struct trace_iterator iter; + unsigned int old_userobj; + int cnt = 0, cpu; + + trace_init_global_iter(&iter); + + for_each_tracing_cpu(cpu) { + atomic_inc(&iter.tr->data[cpu]->disabled); + } + + old_userobj = trace_flags; + + /* don't look at user memory in panic mode */ + trace_flags &= ~TRACE_ITER_SYM_USEROBJ; + + kdb_printf("Dumping ftrace buffer:\n"); + + /* reset all but tr, trace, and overruns */ + memset(&iter.seq, 0, + sizeof(struct trace_iterator) - + offsetof(struct trace_iterator, seq)); + iter.iter_flags |= TRACE_FILE_LAT_FMT; + iter.pos = -1; + + for_each_tracing_cpu(cpu) { + iter.buffer_iter[cpu] = + ring_buffer_read_prepare(iter.tr->buffer, cpu); + ring_buffer_read_start(iter.buffer_iter[cpu]); + tracing_iter_reset(&iter, cpu); + } + + if (!trace_empty(&iter)) + trace_find_next_entry_inc(&iter); + while (!trace_empty(&iter)) { + if (!cnt) + kdb_printf("---------------------------------\n"); + cnt++; + + if (trace_find_next_entry_inc(&iter) != NULL && !skip_lines) + print_trace_line(&iter); + if (!skip_lines) + trace_printk_seq(&iter.seq); + else + skip_lines--; + if (KDB_FLAG(CMD_INTERRUPT)) + goto out; + } + + if (!cnt) + kdb_printf(" (ftrace buffer empty)\n"); + else + kdb_printf("---------------------------------\n"); + +out: + trace_flags = old_userobj; + + for_each_tracing_cpu(cpu) { + atomic_dec(&iter.tr->data[cpu]->disabled); + } + + for_each_tracing_cpu(cpu) + if (iter.buffer_iter[cpu]) + ring_buffer_read_finish(iter.buffer_iter[cpu]); +} + +/* + * kdb_ftdump - Dump the ftrace log buffer + */ +static int kdb_ftdump(int argc, const char **argv) +{ + int skip_lines = 0; + char *cp; + + if (argc > 1) + return KDB_ARGCOUNT; + + if (argc) { + skip_lines = simple_strtol(argv[1], &cp, 0); + if (*cp) + skip_lines = 0; + } + + kdb_trap_printk++; + ftrace_dump_buf(skip_lines); + kdb_trap_printk--; + + return 0; +} + +static __init int kdb_ftrace_register(void) +{ + kdb_register_repeat("ftdump", kdb_ftdump, "", "Dump ftrace log", + 0, KDB_REPEAT_NONE); + return 0; +} + +late_initcall(kdb_ftrace_register); -- cgit v1.2.3 From 19063c776fe745fab11216422cf56489ee83b452 Mon Sep 17 00:00:00 2001 From: Jason Wessel Date: Thu, 5 Aug 2010 09:22:23 -0500 Subject: ftrace,kdb: Allow dumping a specific cpu's buffer with ftdump In systems with more than one processor it is desirable to look at the per cpu trace buffers. Signed-off-by: Jason Wessel Acked-by: Steven Rostedt CC: Frederic Weisbecker --- kernel/trace/trace_kdb.c | 37 +++++++++++++++++++++++++++---------- 1 file changed, 27 insertions(+), 10 deletions(-) (limited to 'kernel/trace/trace_kdb.c') diff --git a/kernel/trace/trace_kdb.c b/kernel/trace/trace_kdb.c index 44cbda25b0a5..7b8ecd751d93 100644 --- a/kernel/trace/trace_kdb.c +++ b/kernel/trace/trace_kdb.c @@ -17,7 +17,7 @@ #include "trace.h" #include "trace_output.h" -static void ftrace_dump_buf(int skip_lines) +static void ftrace_dump_buf(int skip_lines, long cpu_file) { /* use static because iter can be a bit big for the stack */ static struct trace_iterator iter; @@ -44,13 +44,20 @@ static void ftrace_dump_buf(int skip_lines) iter.iter_flags |= TRACE_FILE_LAT_FMT; iter.pos = -1; - for_each_tracing_cpu(cpu) { - iter.buffer_iter[cpu] = + if (cpu_file == TRACE_PIPE_ALL_CPU) { + for_each_tracing_cpu(cpu) { + iter.buffer_iter[cpu] = ring_buffer_read_prepare(iter.tr->buffer, cpu); - ring_buffer_read_start(iter.buffer_iter[cpu]); - tracing_iter_reset(&iter, cpu); + ring_buffer_read_start(iter.buffer_iter[cpu]); + tracing_iter_reset(&iter, cpu); + } + } else { + iter.cpu_file = cpu_file; + iter.buffer_iter[cpu_file] = + ring_buffer_read_prepare(iter.tr->buffer, cpu_file); + ring_buffer_read_start(iter.buffer_iter[cpu_file]); + tracing_iter_reset(&iter, cpu_file); } - if (!trace_empty(&iter)) trace_find_next_entry_inc(&iter); while (!trace_empty(&iter)) { @@ -91,9 +98,10 @@ out: static int kdb_ftdump(int argc, const char **argv) { int skip_lines = 0; + long cpu_file; char *cp; - if (argc > 1) + if (argc > 2) return KDB_ARGCOUNT; if (argc) { @@ -102,8 +110,17 @@ static int kdb_ftdump(int argc, const char **argv) skip_lines = 0; } + if (argc == 2) { + cpu_file = simple_strtol(argv[2], &cp, 0); + if (*cp || cpu_file >= NR_CPUS || cpu_file < 0 || + !cpu_online(cpu_file)) + return KDB_BADINT; + } else { + cpu_file = TRACE_PIPE_ALL_CPU; + } + kdb_trap_printk++; - ftrace_dump_buf(skip_lines); + ftrace_dump_buf(skip_lines, cpu_file); kdb_trap_printk--; return 0; @@ -111,8 +128,8 @@ static int kdb_ftdump(int argc, const char **argv) static __init int kdb_ftrace_register(void) { - kdb_register_repeat("ftdump", kdb_ftdump, "", "Dump ftrace log", - 0, KDB_REPEAT_NONE); + kdb_register_repeat("ftdump", kdb_ftdump, "[skip_#lines] [cpu]", + "Dump ftrace log", 0, KDB_REPEAT_NONE); return 0; } -- cgit v1.2.3