[linux-2.6-block.git] / kernel / trace / trace_kdb.c

// SPDX-License-Identifier: GPL-2.0
/*
 * kdb helper for dumping the ftrace buffer
 *
 * Copyright (C) 2010 Jason Wessel <jason.wessel@windriver.com>
 *
 * ftrace_dump_buf based on ftrace_dump:
 * Copyright (C) 2007-2008 Steven Rostedt <srostedt@redhat.com>
 * Copyright (C) 2008 Ingo Molnar <mingo@redhat.com>
 *
 */
#include <linux/init.h>
#include <linux/kgdb.h>
#include <linux/kdb.h>
#include <linux/ftrace.h>

#include "trace.h"
#include "trace_output.h"

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;
	static struct ring_buffer_iter *buffer_iter[CONFIG_NR_CPUS];
	struct trace_array *tr;
	unsigned int old_userobj;
	int cnt = 0, cpu;

	trace_init_global_iter(&iter);
	iter.buffer_iter = buffer_iter;
	tr = iter.tr;

	for_each_tracing_cpu(cpu) {
		atomic_inc(&per_cpu_ptr(iter.trace_buffer->data, cpu)->disabled);
	}

	old_userobj = tr->trace_flags;

	/* don't look at user memory in panic mode */
	tr->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;

	if (cpu_file == RING_BUFFER_ALL_CPUS) {
		for_each_tracing_cpu(cpu) {
			iter.buffer_iter[cpu] =
			ring_buffer_read_prepare(iter.trace_buffer->buffer, 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.trace_buffer->buffer, cpu_file);
		ring_buffer_read_start(iter.buffer_iter[cpu_file]);
		tracing_iter_reset(&iter, cpu_file);
	}

	while (trace_find_next_entry_inc(&iter)) {
		if (!cnt)
			kdb_printf("---------------------------------\n");
		cnt++;

		if (!skip_lines) {
			print_trace_line(&iter);
			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:
	tr->trace_flags = old_userobj;

	for_each_tracing_cpu(cpu) {
		atomic_dec(&per_cpu_ptr(iter.trace_buffer->data, cpu)->disabled);
	}

	for_each_tracing_cpu(cpu) {
		if (iter.buffer_iter[cpu]) {
			ring_buffer_read_finish(iter.buffer_iter[cpu]);
			iter.buffer_iter[cpu] = NULL;
		}
	}
}

/*
 * kdb_ftdump - Dump the ftrace log buffer
 */
static int kdb_ftdump(int argc, const char **argv)
{
	int skip_lines = 0;
	long cpu_file;
	char *cp;

	if (argc > 2)
		return KDB_ARGCOUNT;

	if (argc) {
		skip_lines = simple_strtol(argv[1], &cp, 0);
		if (*cp)
			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 = RING_BUFFER_ALL_CPUS;
	}

	kdb_trap_printk++;
	ftrace_dump_buf(skip_lines, cpu_file);
	kdb_trap_printk--;

	return 0;
}

static __init int kdb_ftrace_register(void)
{
	kdb_register_flags("ftdump", kdb_ftdump, "[skip_#lines] [cpu]",
			    "Dump ftrace log", 0, KDB_ENABLE_ALWAYS_SAFE);
	return 0;
}

late_initcall(kdb_ftrace_register);
Commit	Line	Data
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
955b61e5 JW	33	for_each_tracing_cpu(cpu) {
12883efb	34	atomic_inc(&per_cpu_ptr(iter.trace_buffer->data, cpu)->disabled);
955b61e5 JW	35	}
955b61e5 JW	36
983f938a	37	old_userobj = tr->trace_flags;
955b61e5 JW	38
955b61e5 JW	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) {
19063c77 JW	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]);
19063c77 JW	63	tracing_iter_reset(&iter, cpu_file);
955b61e5	64	}
8520dedb DT	65
8520dedb DT	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	}
8520dedb DT	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
955b61e5 JW	90	for_each_tracing_cpu(cpu) {
12883efb	91	atomic_dec(&per_cpu_ptr(iter.trace_buffer->data, cpu)->disabled);
955b61e5 JW	92	}
955b61e5 JW	93
c270cc75 DT	94	for_each_tracing_cpu(cpu) {
c270cc75 DT	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;
955b61e5 JW	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	}
19063c77 JW	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);