Adding upstream version 4.19.249.upstream/4.19.249

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 8709 insertions, 0 deletions

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
new file mode 100644
index 000000000..5b7a6e9b0
--- /dev/null
+++ b/kernel/trace/trace.c
@@ -0,0 +1,8709 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * ring buffer based function tracer
+ *
+ * Copyright (C) 2007-2012 Steven Rostedt <srostedt@redhat.com>
+ * Copyright (C) 2008 Ingo Molnar <mingo@redhat.com>
+ *
+ * Originally taken from the RT patch by:
+ *    Arnaldo Carvalho de Melo <acme@redhat.com>
+ *
+ * Based on code from the latency_tracer, that is:
+ *  Copyright (C) 2004-2006 Ingo Molnar
+ *  Copyright (C) 2004 Nadia Yvette Chambers
+ */
+#include <linux/ring_buffer.h>
+#include <generated/utsrelease.h>
+#include <linux/stacktrace.h>
+#include <linux/writeback.h>
+#include <linux/kallsyms.h>
+#include <linux/seq_file.h>
+#include <linux/notifier.h>
+#include <linux/irqflags.h>
+#include <linux/debugfs.h>
+#include <linux/tracefs.h>
+#include <linux/pagemap.h>
+#include <linux/hardirq.h>
+#include <linux/linkage.h>
+#include <linux/uaccess.h>
+#include <linux/vmalloc.h>
+#include <linux/ftrace.h>
+#include <linux/module.h>
+#include <linux/percpu.h>
+#include <linux/splice.h>
+#include <linux/kdebug.h>
+#include <linux/string.h>
+#include <linux/mount.h>
+#include <linux/rwsem.h>
+#include <linux/slab.h>
+#include <linux/ctype.h>
+#include <linux/init.h>
+#include <linux/poll.h>
+#include <linux/nmi.h>
+#include <linux/fs.h>
+#include <linux/trace.h>
+#include <linux/sched/clock.h>
+#include <linux/sched/rt.h>
+
+#include "trace.h"
+#include "trace_output.h"
+
+/*
+ * On boot up, the ring buffer is set to the minimum size, so that
+ * we do not waste memory on systems that are not using tracing.
+ */
+bool ring_buffer_expanded;
+
+/*
+ * We need to change this state when a selftest is running.
+ * A selftest will lurk into the ring-buffer to count the
+ * entries inserted during the selftest although some concurrent
+ * insertions into the ring-buffer such as trace_printk could occurred
+ * at the same time, giving false positive or negative results.
+ */
+static bool __read_mostly tracing_selftest_running;
+
+/*
+ * If a tracer is running, we do not want to run SELFTEST.
+ */
+bool __read_mostly tracing_selftest_disabled;
+
+/* Pipe tracepoints to printk */
+struct trace_iterator *tracepoint_print_iter;
+int tracepoint_printk;
+static DEFINE_STATIC_KEY_FALSE(tracepoint_printk_key);
+
+/* For tracers that don't implement custom flags */
+static struct tracer_opt dummy_tracer_opt[] = {
+	{ }
+};
+
+static int
+dummy_set_flag(struct trace_array *tr, u32 old_flags, u32 bit, int set)
+{
+	return 0;
+}
+
+/*
+ * To prevent the comm cache from being overwritten when no
+ * tracing is active, only save the comm when a trace event
+ * occurred.
+ */
+static DEFINE_PER_CPU(bool, trace_taskinfo_save);
+
+/*
+ * Kill all tracing for good (never come back).
+ * It is initialized to 1 but will turn to zero if the initialization
+ * of the tracer is successful. But that is the only place that sets
+ * this back to zero.
+ */
+static int tracing_disabled = 1;
+
+cpumask_var_t __read_mostly	tracing_buffer_mask;
+
+/*
+ * ftrace_dump_on_oops - variable to dump ftrace buffer on oops
+ *
+ * If there is an oops (or kernel panic) and the ftrace_dump_on_oops
+ * is set, then ftrace_dump is called. This will output the contents
+ * of the ftrace buffers to the console.  This is very useful for
+ * capturing traces that lead to crashes and outputing it to a
+ * serial console.
+ *
+ * It is default off, but you can enable it with either specifying
+ * "ftrace_dump_on_oops" in the kernel command line, or setting
+ * /proc/sys/kernel/ftrace_dump_on_oops
+ * Set 1 if you want to dump buffers of all CPUs
+ * Set 2 if you want to dump the buffer of the CPU that triggered oops
+ */
+
+enum ftrace_dump_mode ftrace_dump_on_oops;
+
+/* When set, tracing will stop when a WARN*() is hit */
+int __disable_trace_on_warning;
+
+#ifdef CONFIG_TRACE_EVAL_MAP_FILE
+/* Map of enums to their values, for "eval_map" file */
+struct trace_eval_map_head {
+	struct module			*mod;
+	unsigned long			length;
+};
+
+union trace_eval_map_item;
+
+struct trace_eval_map_tail {
+	/*
+	 * "end" is first and points to NULL as it must be different
+	 * than "mod" or "eval_string"
+	 */
+	union trace_eval_map_item	*next;
+	const char			*end;	/* points to NULL */
+};
+
+static DEFINE_MUTEX(trace_eval_mutex);
+
+/*
+ * The trace_eval_maps are saved in an array with two extra elements,
+ * one at the beginning, and one at the end. The beginning item contains
+ * the count of the saved maps (head.length), and the module they
+ * belong to if not built in (head.mod). The ending item contains a
+ * pointer to the next array of saved eval_map items.
+ */
+union trace_eval_map_item {
+	struct trace_eval_map		map;
+	struct trace_eval_map_head	head;
+	struct trace_eval_map_tail	tail;
+};
+
+static union trace_eval_map_item *trace_eval_maps;
+#endif /* CONFIG_TRACE_EVAL_MAP_FILE */
+
+static int tracing_set_tracer(struct trace_array *tr, const char *buf);
+
+#define MAX_TRACER_SIZE		100
+static char bootup_tracer_buf[MAX_TRACER_SIZE] __initdata;
+static char *default_bootup_tracer;
+
+static bool allocate_snapshot;
+
+static int __init set_cmdline_ftrace(char *str)
+{
+	strlcpy(bootup_tracer_buf, str, MAX_TRACER_SIZE);
+	default_bootup_tracer = bootup_tracer_buf;
+	/* We are using ftrace early, expand it */
+	ring_buffer_expanded = true;
+	return 1;
+}
+__setup("ftrace=", set_cmdline_ftrace);
+
+static int __init set_ftrace_dump_on_oops(char *str)
+{
+	if (*str++ != '=' || !*str) {
+		ftrace_dump_on_oops = DUMP_ALL;
+		return 1;
+	}
+
+	if (!strcmp("orig_cpu", str)) {
+		ftrace_dump_on_oops = DUMP_ORIG;
+                return 1;
+        }
+
+        return 0;
+}
+__setup("ftrace_dump_on_oops", set_ftrace_dump_on_oops);
+
+static int __init stop_trace_on_warning(char *str)
+{
+	if ((strcmp(str, "=0") != 0 && strcmp(str, "=off") != 0))
+		__disable_trace_on_warning = 1;
+	return 1;
+}
+__setup("traceoff_on_warning", stop_trace_on_warning);
+
+static int __init boot_alloc_snapshot(char *str)
+{
+	allocate_snapshot = true;
+	/* We also need the main ring buffer expanded */
+	ring_buffer_expanded = true;
+	return 1;
+}
+__setup("alloc_snapshot", boot_alloc_snapshot);
+
+
+static char trace_boot_options_buf[MAX_TRACER_SIZE] __initdata;
+
+static int __init set_trace_boot_options(char *str)
+{
+	strlcpy(trace_boot_options_buf, str, MAX_TRACER_SIZE);
+	return 0;
+}
+__setup("trace_options=", set_trace_boot_options);
+
+static char trace_boot_clock_buf[MAX_TRACER_SIZE] __initdata;
+static char *trace_boot_clock __initdata;
+
+static int __init set_trace_boot_clock(char *str)
+{
+	strlcpy(trace_boot_clock_buf, str, MAX_TRACER_SIZE);
+	trace_boot_clock = trace_boot_clock_buf;
+	return 0;
+}
+__setup("trace_clock=", set_trace_boot_clock);
+
+static int __init set_tracepoint_printk(char *str)
+{
+	/* Ignore the "tp_printk_stop_on_boot" param */
+	if (*str == '_')
+		return 0;
+
+	if ((strcmp(str, "=0") != 0 && strcmp(str, "=off") != 0))
+		tracepoint_printk = 1;
+	return 1;
+}
+__setup("tp_printk", set_tracepoint_printk);
+
+unsigned long long ns2usecs(u64 nsec)
+{
+	nsec += 500;
+	do_div(nsec, 1000);
+	return nsec;
+}
+
+/* trace_flags holds trace_options default values */
+#define TRACE_DEFAULT_FLAGS						\
+	(FUNCTION_DEFAULT_FLAGS |					\
+	 TRACE_ITER_PRINT_PARENT | TRACE_ITER_PRINTK |			\
+	 TRACE_ITER_ANNOTATE | TRACE_ITER_CONTEXT_INFO |		\
+	 TRACE_ITER_RECORD_CMD | TRACE_ITER_OVERWRITE |			\
+	 TRACE_ITER_IRQ_INFO | TRACE_ITER_MARKERS)
+
+/* trace_options that are only supported by global_trace */
+#define TOP_LEVEL_TRACE_FLAGS (TRACE_ITER_PRINTK |			\
+	       TRACE_ITER_PRINTK_MSGONLY | TRACE_ITER_RECORD_CMD)
+
+/* trace_flags that are default zero for instances */
+#define ZEROED_TRACE_FLAGS \
+	(TRACE_ITER_EVENT_FORK | TRACE_ITER_FUNC_FORK)
+
+/*
+ * The global_trace is the descriptor that holds the top-level tracing
+ * buffers for the live tracing.
+ */
+static struct trace_array global_trace = {
+	.trace_flags = TRACE_DEFAULT_FLAGS,
+};
+
+LIST_HEAD(ftrace_trace_arrays);
+
+int trace_array_get(struct trace_array *this_tr)
+{
+	struct trace_array *tr;
+	int ret = -ENODEV;
+
+	mutex_lock(&trace_types_lock);
+	list_for_each_entry(tr, &ftrace_trace_arrays, list) {
+		if (tr == this_tr) {
+			tr->ref++;
+			ret = 0;
+			break;
+		}
+	}
+	mutex_unlock(&trace_types_lock);
+
+	return ret;
+}
+
+static void __trace_array_put(struct trace_array *this_tr)
+{
+	WARN_ON(!this_tr->ref);
+	this_tr->ref--;
+}
+
+void trace_array_put(struct trace_array *this_tr)
+{
+	mutex_lock(&trace_types_lock);
+	__trace_array_put(this_tr);
+	mutex_unlock(&trace_types_lock);
+}
+
+int call_filter_check_discard(struct trace_event_call *call, void *rec,
+			      struct ring_buffer *buffer,
+			      struct ring_buffer_event *event)
+{
+	if (unlikely(call->flags & TRACE_EVENT_FL_FILTERED) &&
+	    !filter_match_preds(call->filter, rec)) {
+		__trace_event_discard_commit(buffer, event);
+		return 1;
+	}
+
+	return 0;
+}
+
+void trace_free_pid_list(struct trace_pid_list *pid_list)
+{
+	vfree(pid_list->pids);
+	kfree(pid_list);
+}
+
+/**
+ * trace_find_filtered_pid - check if a pid exists in a filtered_pid list
+ * @filtered_pids: The list of pids to check
+ * @search_pid: The PID to find in @filtered_pids
+ *
+ * Returns true if @search_pid is fonud in @filtered_pids, and false otherwis.
+ */
+bool
+trace_find_filtered_pid(struct trace_pid_list *filtered_pids, pid_t search_pid)
+{
+	/*
+	 * If pid_max changed after filtered_pids was created, we
+	 * by default ignore all pids greater than the previous pid_max.
+	 */
+	if (search_pid >= filtered_pids->pid_max)
+		return false;
+
+	return test_bit(search_pid, filtered_pids->pids);
+}
+
+/**
+ * trace_ignore_this_task - should a task be ignored for tracing
+ * @filtered_pids: The list of pids to check
+ * @task: The task that should be ignored if not filtered
+ *
+ * Checks if @task should be traced or not from @filtered_pids.
+ * Returns true if @task should *NOT* be traced.
+ * Returns false if @task should be traced.
+ */
+bool
+trace_ignore_this_task(struct trace_pid_list *filtered_pids, struct task_struct *task)
+{
+	/*
+	 * Return false, because if filtered_pids does not exist,
+	 * all pids are good to trace.
+	 */
+	if (!filtered_pids)
+		return false;
+
+	return !trace_find_filtered_pid(filtered_pids, task->pid);
+}
+
+/**
+ * trace_pid_filter_add_remove_task - Add or remove a task from a pid_list
+ * @pid_list: The list to modify
+ * @self: The current task for fork or NULL for exit
+ * @task: The task to add or remove
+ *
+ * If adding a task, if @self is defined, the task is only added if @self
+ * is also included in @pid_list. This happens on fork and tasks should
+ * only be added when the parent is listed. If @self is NULL, then the
+ * @task pid will be removed from the list, which would happen on exit
+ * of a task.
+ */
+void trace_filter_add_remove_task(struct trace_pid_list *pid_list,
+				  struct task_struct *self,
+				  struct task_struct *task)
+{
+	if (!pid_list)
+		return;
+
+	/* For forks, we only add if the forking task is listed */
+	if (self) {
+		if (!trace_find_filtered_pid(pid_list, self->pid))
+			return;
+	}
+
+	/* Sorry, but we don't support pid_max changing after setting */
+	if (task->pid >= pid_list->pid_max)
+		return;
+
+	/* "self" is set for forks, and NULL for exits */
+	if (self)
+		set_bit(task->pid, pid_list->pids);
+	else
+		clear_bit(task->pid, pid_list->pids);
+}
+
+/**
+ * trace_pid_next - Used for seq_file to get to the next pid of a pid_list
+ * @pid_list: The pid list to show
+ * @v: The last pid that was shown (+1 the actual pid to let zero be displayed)
+ * @pos: The position of the file
+ *
+ * This is used by the seq_file "next" operation to iterate the pids
+ * listed in a trace_pid_list structure.
+ *
+ * Returns the pid+1 as we want to display pid of zero, but NULL would
+ * stop the iteration.
+ */
+void *trace_pid_next(struct trace_pid_list *pid_list, void *v, loff_t *pos)
+{
+	unsigned long pid = (unsigned long)v;
+
+	(*pos)++;
+
+	/* pid already is +1 of the actual prevous bit */
+	pid = find_next_bit(pid_list->pids, pid_list->pid_max, pid);
+
+	/* Return pid + 1 to allow zero to be represented */
+	if (pid < pid_list->pid_max)
+		return (void *)(pid + 1);
+
+	return NULL;
+}
+
+/**
+ * trace_pid_start - Used for seq_file to start reading pid lists
+ * @pid_list: The pid list to show
+ * @pos: The position of the file
+ *
+ * This is used by seq_file "start" operation to start the iteration
+ * of listing pids.
+ *
+ * Returns the pid+1 as we want to display pid of zero, but NULL would
+ * stop the iteration.
+ */
+void *trace_pid_start(struct trace_pid_list *pid_list, loff_t *pos)
+{
+	unsigned long pid;
+	loff_t l = 0;
+
+	pid = find_first_bit(pid_list->pids, pid_list->pid_max);
+	if (pid >= pid_list->pid_max)
+		return NULL;
+
+	/* Return pid + 1 so that zero can be the exit value */
+	for (pid++; pid && l < *pos;
+	     pid = (unsigned long)trace_pid_next(pid_list, (void *)pid, &l))
+		;
+	return (void *)pid;
+}
+
+/**
+ * trace_pid_show - show the current pid in seq_file processing
+ * @m: The seq_file structure to write into
+ * @v: A void pointer of the pid (+1) value to display
+ *
+ * Can be directly used by seq_file operations to display the current
+ * pid value.
+ */
+int trace_pid_show(struct seq_file *m, void *v)
+{
+	unsigned long pid = (unsigned long)v - 1;
+
+	seq_printf(m, "%lu\n", pid);
+	return 0;
+}
+
+/* 128 should be much more than enough */
+#define PID_BUF_SIZE		127
+
+int trace_pid_write(struct trace_pid_list *filtered_pids,
+		    struct trace_pid_list **new_pid_list,
+		    const char __user *ubuf, size_t cnt)
+{
+	struct trace_pid_list *pid_list;
+	struct trace_parser parser;
+	unsigned long val;
+	int nr_pids = 0;
+	ssize_t read = 0;
+	ssize_t ret = 0;
+	loff_t pos;
+	pid_t pid;
+
+	if (trace_parser_get_init(&parser, PID_BUF_SIZE + 1))
+		return -ENOMEM;
+
+	/*
+	 * Always recreate a new array. The write is an all or nothing
+	 * operation. Always create a new array when adding new pids by
+	 * the user. If the operation fails, then the current list is
+	 * not modified.
+	 */
+	pid_list = kmalloc(sizeof(*pid_list), GFP_KERNEL);
+	if (!pid_list) {
+		trace_parser_put(&parser);
+		return -ENOMEM;
+	}
+
+	pid_list->pid_max = READ_ONCE(pid_max);
+
+	/* Only truncating will shrink pid_max */
+	if (filtered_pids && filtered_pids->pid_max > pid_list->pid_max)
+		pid_list->pid_max = filtered_pids->pid_max;
+
+	pid_list->pids = vzalloc((pid_list->pid_max + 7) >> 3);
+	if (!pid_list->pids) {
+		trace_parser_put(&parser);
+		kfree(pid_list);
+		return -ENOMEM;
+	}
+
+	if (filtered_pids) {
+		/* copy the current bits to the new max */
+		for_each_set_bit(pid, filtered_pids->pids,
+				 filtered_pids->pid_max) {
+			set_bit(pid, pid_list->pids);
+			nr_pids++;
+		}
+	}
+
+	while (cnt > 0) {
+
+		pos = 0;
+
+		ret = trace_get_user(&parser, ubuf, cnt, &pos);
+		if (ret < 0 || !trace_parser_loaded(&parser))
+			break;
+
+		read += ret;
+		ubuf += ret;
+		cnt -= ret;
+
+		ret = -EINVAL;
+		if (kstrtoul(parser.buffer, 0, &val))
+			break;
+		if (val >= pid_list->pid_max)
+			break;
+
+		pid = (pid_t)val;
+
+		set_bit(pid, pid_list->pids);
+		nr_pids++;
+
+		trace_parser_clear(&parser);
+		ret = 0;
+	}
+	trace_parser_put(&parser);
+
+	if (ret < 0) {
+		trace_free_pid_list(pid_list);
+		return ret;
+	}
+
+	if (!nr_pids) {
+		/* Cleared the list of pids */
+		trace_free_pid_list(pid_list);
+		read = ret;
+		pid_list = NULL;
+	}
+
+	*new_pid_list = pid_list;
+
+	return read;
+}
+
+static u64 buffer_ftrace_now(struct trace_buffer *buf, int cpu)
+{
+	u64 ts;
+
+	/* Early boot up does not have a buffer yet */
+	if (!buf->buffer)
+		return trace_clock_local();
+
+	ts = ring_buffer_time_stamp(buf->buffer, cpu);
+	ring_buffer_normalize_time_stamp(buf->buffer, cpu, &ts);
+
+	return ts;
+}
+
+u64 ftrace_now(int cpu)
+{
+	return buffer_ftrace_now(&global_trace.trace_buffer, cpu);
+}
+
+/**
+ * tracing_is_enabled - Show if global_trace has been disabled
+ *
+ * Shows if the global trace has been enabled or not. It uses the
+ * mirror flag "buffer_disabled" to be used in fast paths such as for
+ * the irqsoff tracer. But it may be inaccurate due to races. If you
+ * need to know the accurate state, use tracing_is_on() which is a little
+ * slower, but accurate.
+ */
+int tracing_is_enabled(void)
+{
+	/*
+	 * For quick access (irqsoff uses this in fast path), just
+	 * return the mirror variable of the state of the ring buffer.
+	 * It's a little racy, but we don't really care.
+	 */
+	smp_rmb();
+	return !global_trace.buffer_disabled;
+}
+
+/*
+ * trace_buf_size is the size in bytes that is allocated
+ * for a buffer. Note, the number of bytes is always rounded
+ * to page size.
+ *
+ * This number is purposely set to a low number of 16384.
+ * If the dump on oops happens, it will be much appreciated
+ * to not have to wait for all that output. Anyway this can be
+ * boot time and run time configurable.
+ */
+#define TRACE_BUF_SIZE_DEFAULT	1441792UL /* 16384 * 88 (sizeof(entry)) */
+
+static unsigned long		trace_buf_size = TRACE_BUF_SIZE_DEFAULT;
+
+/* trace_types holds a link list of available tracers. */
+static struct tracer		*trace_types __read_mostly;
+
+/*
+ * trace_types_lock is used to protect the trace_types list.
+ */
+DEFINE_MUTEX(trace_types_lock);
+
+/*
+ * serialize the access of the ring buffer
+ *
+ * ring buffer serializes readers, but it is low level protection.
+ * The validity of the events (which returns by ring_buffer_peek() ..etc)
+ * are not protected by ring buffer.
+ *
+ * The content of events may become garbage if we allow other process consumes
+ * these events concurrently:
+ *   A) the page of the consumed events may become a normal page
+ *      (not reader page) in ring buffer, and this page will be rewrited
+ *      by events producer.
+ *   B) The page of the consumed events may become a page for splice_read,
+ *      and this page will be returned to system.
+ *
+ * These primitives allow multi process access to different cpu ring buffer
+ * concurrently.
+ *
+ * These primitives don't distinguish read-only and read-consume access.
+ * Multi read-only access are also serialized.
+ */
+
+#ifdef CONFIG_SMP
+static DECLARE_RWSEM(all_cpu_access_lock);
+static DEFINE_PER_CPU(struct mutex, cpu_access_lock);
+
+static inline void trace_access_lock(int cpu)
+{
+	if (cpu == RING_BUFFER_ALL_CPUS) {
+		/* gain it for accessing the whole ring buffer. */
+		down_write(&all_cpu_access_lock);
+	} else {
+		/* gain it for accessing a cpu ring buffer. */
+
+		/* Firstly block other trace_access_lock(RING_BUFFER_ALL_CPUS). */
+		down_read(&all_cpu_access_lock);
+
+		/* Secondly block other access to this @cpu ring buffer. */
+		mutex_lock(&per_cpu(cpu_access_lock, cpu));
+	}
+}
+
+static inline void trace_access_unlock(int cpu)
+{
+	if (cpu == RING_BUFFER_ALL_CPUS) {
+		up_write(&all_cpu_access_lock);
+	} else {
+		mutex_unlock(&per_cpu(cpu_access_lock, cpu));
+		up_read(&all_cpu_access_lock);
+	}
+}
+
+static inline void trace_access_lock_init(void)
+{
+	int cpu;
+
+	for_each_possible_cpu(cpu)
+		mutex_init(&per_cpu(cpu_access_lock, cpu));
+}
+
+#else
+
+static DEFINE_MUTEX(access_lock);
+
+static inline void trace_access_lock(int cpu)
+{
+	(void)cpu;
+	mutex_lock(&access_lock);
+}
+
+static inline void trace_access_unlock(int cpu)
+{
+	(void)cpu;
+	mutex_unlock(&access_lock);
+}
+
+static inline void trace_access_lock_init(void)
+{
+}
+
+#endif
+
+#ifdef CONFIG_STACKTRACE
+static void __ftrace_trace_stack(struct ring_buffer *buffer,
+				 unsigned long flags,
+				 int skip, int pc, struct pt_regs *regs);
+static inline void ftrace_trace_stack(struct trace_array *tr,
+				      struct ring_buffer *buffer,
+				      unsigned long flags,
+				      int skip, int pc, struct pt_regs *regs);
+
+#else
+static inline void __ftrace_trace_stack(struct ring_buffer *buffer,
+					unsigned long flags,
+					int skip, int pc, struct pt_regs *regs)
+{
+}
+static inline void ftrace_trace_stack(struct trace_array *tr,
+				      struct ring_buffer *buffer,
+				      unsigned long flags,
+				      int skip, int pc, struct pt_regs *regs)
+{
+}
+
+#endif
+
+static __always_inline void
+trace_event_setup(struct ring_buffer_event *event,
+		  int type, unsigned long flags, int pc)
+{
+	struct trace_entry *ent = ring_buffer_event_data(event);
+
+	tracing_generic_entry_update(ent, flags, pc);
+	ent->type = type;
+}
+
+static __always_inline struct ring_buffer_event *
+__trace_buffer_lock_reserve(struct ring_buffer *buffer,
+			  int type,
+			  unsigned long len,
+			  unsigned long flags, int pc)
+{
+	struct ring_buffer_event *event;
+
+	event = ring_buffer_lock_reserve(buffer, len);
+	if (event != NULL)
+		trace_event_setup(event, type, flags, pc);
+
+	return event;
+}
+
+void tracer_tracing_on(struct trace_array *tr)
+{
+	if (tr->trace_buffer.buffer)
+		ring_buffer_record_on(tr->trace_buffer.buffer);
+	/*
+	 * This flag is looked at when buffers haven't been allocated
+	 * yet, or by some tracers (like irqsoff), that just want to
+	 * know if the ring buffer has been disabled, but it can handle
+	 * races of where it gets disabled but we still do a record.
+	 * As the check is in the fast path of the tracers, it is more
+	 * important to be fast than accurate.
+	 */
+	tr->buffer_disabled = 0;
+	/* Make the flag seen by readers */
+	smp_wmb();
+}
+
+/**
+ * tracing_on - enable tracing buffers
+ *
+ * This function enables tracing buffers that may have been
+ * disabled with tracing_off.
+ */
+void tracing_on(void)
+{
+	tracer_tracing_on(&global_trace);
+}
+EXPORT_SYMBOL_GPL(tracing_on);
+
+
+static __always_inline void
+__buffer_unlock_commit(struct ring_buffer *buffer, struct ring_buffer_event *event)
+{
+	__this_cpu_write(trace_taskinfo_save, true);
+
+	/* If this is the temp buffer, we need to commit fully */
+	if (this_cpu_read(trace_buffered_event) == event) {
+		/* Length is in event->array[0] */
+		ring_buffer_write(buffer, event->array[0], &event->array[1]);
+		/* Release the temp buffer */
+		this_cpu_dec(trace_buffered_event_cnt);
+	} else
+		ring_buffer_unlock_commit(buffer, event);
+}
+
+/**
+ * __trace_puts - write a constant string into the trace buffer.
+ * @ip:	   The address of the caller
+ * @str:   The constant string to write
+ * @size:  The size of the string.
+ */
+int __trace_puts(unsigned long ip, const char *str, int size)
+{
+	struct ring_buffer_event *event;
+	struct ring_buffer *buffer;
+	struct print_entry *entry;
+	unsigned long irq_flags;
+	int alloc;
+	int pc;
+
+	if (!(global_trace.trace_flags & TRACE_ITER_PRINTK))
+		return 0;
+
+	pc = preempt_count();
+
+	if (unlikely(tracing_selftest_running || tracing_disabled))
+		return 0;
+
+	alloc = sizeof(*entry) + size + 2; /* possible \n added */
+
+	local_save_flags(irq_flags);
+	buffer = global_trace.trace_buffer.buffer;
+	event = __trace_buffer_lock_reserve(buffer, TRACE_PRINT, alloc, 
+					    irq_flags, pc);
+	if (!event)
+		return 0;
+
+	entry = ring_buffer_event_data(event);
+	entry->ip = ip;
+
+	memcpy(&entry->buf, str, size);
+
+	/* Add a newline if necessary */
+	if (entry->buf[size - 1] != '\n') {
+		entry->buf[size] = '\n';
+		entry->buf[size + 1] = '\0';
+	} else
+		entry->buf[size] = '\0';
+
+	__buffer_unlock_commit(buffer, event);
+	ftrace_trace_stack(&global_trace, buffer, irq_flags, 4, pc, NULL);
+
+	return size;
+}
+EXPORT_SYMBOL_GPL(__trace_puts);
+
+/**
+ * __trace_bputs - write the pointer to a constant string into trace buffer
+ * @ip:	   The address of the caller
+ * @str:   The constant string to write to the buffer to
+ */
+int __trace_bputs(unsigned long ip, const char *str)
+{
+	struct ring_buffer_event *event;
+	struct ring_buffer *buffer;
+	struct bputs_entry *entry;
+	unsigned long irq_flags;
+	int size = sizeof(struct bputs_entry);
+	int pc;
+
+	if (!(global_trace.trace_flags & TRACE_ITER_PRINTK))
+		return 0;
+
+	pc = preempt_count();
+
+	if (unlikely(tracing_selftest_running || tracing_disabled))
+		return 0;
+
+	local_save_flags(irq_flags);
+	buffer = global_trace.trace_buffer.buffer;
+	event = __trace_buffer_lock_reserve(buffer, TRACE_BPUTS, size,
+					    irq_flags, pc);
+	if (!event)
+		return 0;
+
+	entry = ring_buffer_event_data(event);
+	entry->ip			= ip;
+	entry->str			= str;
+
+	__buffer_unlock_commit(buffer, event);
+	ftrace_trace_stack(&global_trace, buffer, irq_flags, 4, pc, NULL);
+
+	return 1;
+}
+EXPORT_SYMBOL_GPL(__trace_bputs);
+
+#ifdef CONFIG_TRACER_SNAPSHOT
+void tracing_snapshot_instance(struct trace_array *tr)
+{
+	struct tracer *tracer = tr->current_trace;
+	unsigned long flags;
+
+	if (in_nmi()) {
+		internal_trace_puts("*** SNAPSHOT CALLED FROM NMI CONTEXT ***\n");
+		internal_trace_puts("*** snapshot is being ignored        ***\n");
+		return;
+	}
+
+	if (!tr->allocated_snapshot) {
+		internal_trace_puts("*** SNAPSHOT NOT ALLOCATED ***\n");
+		internal_trace_puts("*** stopping trace here!   ***\n");
+		tracing_off();
+		return;
+	}
+
+	/* Note, snapshot can not be used when the tracer uses it */
+	if (tracer->use_max_tr) {
+		internal_trace_puts("*** LATENCY TRACER ACTIVE ***\n");
+		internal_trace_puts("*** Can not use snapshot (sorry) ***\n");
+		return;
+	}
+
+	local_irq_save(flags);
+	update_max_tr(tr, current, smp_processor_id());
+	local_irq_restore(flags);
+}
+
+/**
+ * tracing_snapshot - take a snapshot of the current buffer.
+ *
+ * This causes a swap between the snapshot buffer and the current live
+ * tracing buffer. You can use this to take snapshots of the live
+ * trace when some condition is triggered, but continue to trace.
+ *
+ * Note, make sure to allocate the snapshot with either
+ * a tracing_snapshot_alloc(), or by doing it manually
+ * with: echo 1 > /sys/kernel/debug/tracing/snapshot
+ *
+ * If the snapshot buffer is not allocated, it will stop tracing.
+ * Basically making a permanent snapshot.
+ */
+void tracing_snapshot(void)
+{
+	struct trace_array *tr = &global_trace;
+
+	tracing_snapshot_instance(tr);
+}
+EXPORT_SYMBOL_GPL(tracing_snapshot);
+
+static int resize_buffer_duplicate_size(struct trace_buffer *trace_buf,
+					struct trace_buffer *size_buf, int cpu_id);
+static void set_buffer_entries(struct trace_buffer *buf, unsigned long val);
+
+int tracing_alloc_snapshot_instance(struct trace_array *tr)
+{
+	int ret;
+
+	if (!tr->allocated_snapshot) {
+
+		/* allocate spare buffer */
+		ret = resize_buffer_duplicate_size(&tr->max_buffer,
+				   &tr->trace_buffer, RING_BUFFER_ALL_CPUS);
+		if (ret < 0)
+			return ret;
+
+		tr->allocated_snapshot = true;
+	}
+
+	return 0;
+}
+
+static void free_snapshot(struct trace_array *tr)
+{
+	/*
+	 * We don't free the ring buffer. instead, resize it because
+	 * The max_tr ring buffer has some state (e.g. ring->clock) and
+	 * we want preserve it.
+	 */
+	ring_buffer_resize(tr->max_buffer.buffer, 1, RING_BUFFER_ALL_CPUS);
+	set_buffer_entries(&tr->max_buffer, 1);
+	tracing_reset_online_cpus(&tr->max_buffer);
+	tr->allocated_snapshot = false;
+}
+
+/**
+ * tracing_alloc_snapshot - allocate snapshot buffer.
+ *
+ * This only allocates the snapshot buffer if it isn't already
+ * allocated - it doesn't also take a snapshot.
+ *
+ * This is meant to be used in cases where the snapshot buffer needs
+ * to be set up for events that can't sleep but need to be able to
+ * trigger a snapshot.
+ */
+int tracing_alloc_snapshot(void)
+{
+	struct trace_array *tr = &global_trace;
+	int ret;
+
+	ret = tracing_alloc_snapshot_instance(tr);
+	WARN_ON(ret < 0);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(tracing_alloc_snapshot);
+
+/**
+ * tracing_snapshot_alloc - allocate and take a snapshot of the current buffer.
+ *
+ * This is similar to tracing_snapshot(), but it will allocate the
+ * snapshot buffer if it isn't already allocated. Use this only
+ * where it is safe to sleep, as the allocation may sleep.
+ *
+ * This causes a swap between the snapshot buffer and the current live
+ * tracing buffer. You can use this to take snapshots of the live
+ * trace when some condition is triggered, but continue to trace.
+ */
+void tracing_snapshot_alloc(void)
+{
+	int ret;
+
+	ret = tracing_alloc_snapshot();
+	if (ret < 0)
+		return;
+
+	tracing_snapshot();
+}
+EXPORT_SYMBOL_GPL(tracing_snapshot_alloc);
+#else
+void tracing_snapshot(void)
+{
+	WARN_ONCE(1, "Snapshot feature not enabled, but internal snapshot used");
+}
+EXPORT_SYMBOL_GPL(tracing_snapshot);
+int tracing_alloc_snapshot(void)
+{
+	WARN_ONCE(1, "Snapshot feature not enabled, but snapshot allocation used");
+	return -ENODEV;
+}
+EXPORT_SYMBOL_GPL(tracing_alloc_snapshot);
+void tracing_snapshot_alloc(void)
+{
+	/* Give warning */
+	tracing_snapshot();
+}
+EXPORT_SYMBOL_GPL(tracing_snapshot_alloc);
+#endif /* CONFIG_TRACER_SNAPSHOT */
+
+void tracer_tracing_off(struct trace_array *tr)
+{
+	if (tr->trace_buffer.buffer)
+		ring_buffer_record_off(tr->trace_buffer.buffer);
+	/*
+	 * This flag is looked at when buffers haven't been allocated
+	 * yet, or by some tracers (like irqsoff), that just want to
+	 * know if the ring buffer has been disabled, but it can handle
+	 * races of where it gets disabled but we still do a record.
+	 * As the check is in the fast path of the tracers, it is more
+	 * important to be fast than accurate.
+	 */
+	tr->buffer_disabled = 1;
+	/* Make the flag seen by readers */
+	smp_wmb();
+}
+
+/**
+ * tracing_off - turn off tracing buffers
+ *
+ * This function stops the tracing buffers from recording data.
+ * It does not disable any overhead the tracers themselves may
+ * be causing. This function simply causes all recording to
+ * the ring buffers to fail.
+ */
+void tracing_off(void)
+{
+	tracer_tracing_off(&global_trace);
+}
+EXPORT_SYMBOL_GPL(tracing_off);
+
+void disable_trace_on_warning(void)
+{
+	if (__disable_trace_on_warning)
+		tracing_off();
+}
+
+/**
+ * tracer_tracing_is_on - show real state of ring buffer enabled
+ * @tr : the trace array to know if ring buffer is enabled
+ *
+ * Shows real state of the ring buffer if it is enabled or not.
+ */
+bool tracer_tracing_is_on(struct trace_array *tr)
+{
+	if (tr->trace_buffer.buffer)
+		return ring_buffer_record_is_on(tr->trace_buffer.buffer);
+	return !tr->buffer_disabled;
+}
+
+/**
+ * tracing_is_on - show state of ring buffers enabled
+ */
+int tracing_is_on(void)
+{
+	return tracer_tracing_is_on(&global_trace);
+}
+EXPORT_SYMBOL_GPL(tracing_is_on);
+
+static int __init set_buf_size(char *str)
+{
+	unsigned long buf_size;
+
+	if (!str)
+		return 0;
+	buf_size = memparse(str, &str);
+	/*
+	 * nr_entries can not be zero and the startup
+	 * tests require some buffer space. Therefore
+	 * ensure we have at least 4096 bytes of buffer.
+	 */
+	trace_buf_size = max(4096UL, buf_size);
+	return 1;
+}
+__setup("trace_buf_size=", set_buf_size);
+
+static int __init set_tracing_thresh(char *str)
+{
+	unsigned long threshold;
+	int ret;
+
+	if (!str)
+		return 0;
+	ret = kstrtoul(str, 0, &threshold);
+	if (ret < 0)
+		return 0;
+	tracing_thresh = threshold * 1000;
+	return 1;
+}
+__setup("tracing_thresh=", set_tracing_thresh);
+
+unsigned long nsecs_to_usecs(unsigned long nsecs)
+{
+	return nsecs / 1000;
+}
+
+/*
+ * TRACE_FLAGS is defined as a tuple matching bit masks with strings.
+ * It uses C(a, b) where 'a' is the eval (enum) name and 'b' is the string that
+ * matches it. By defining "C(a, b) b", TRACE_FLAGS becomes a list
+ * of strings in the order that the evals (enum) were defined.
+ */
+#undef C
+#define C(a, b) b
+
+/* These must match the bit postions in trace_iterator_flags */
+static const char *trace_options[] = {
+	TRACE_FLAGS
+	NULL
+};
+
+static struct {
+	u64 (*func)(void);
+	const char *name;
+	int in_ns;		/* is this clock in nanoseconds? */
+} trace_clocks[] = {
+	{ trace_clock_local,		"local",	1 },
+	{ trace_clock_global,		"global",	1 },
+	{ trace_clock_counter,		"counter",	0 },
+	{ trace_clock_jiffies,		"uptime",	0 },
+	{ trace_clock,			"perf",		1 },
+	{ ktime_get_mono_fast_ns,	"mono",		1 },
+	{ ktime_get_raw_fast_ns,	"mono_raw",	1 },
+	{ ktime_get_boot_fast_ns,	"boot",		1 },
+	ARCH_TRACE_CLOCKS
+};
+
+bool trace_clock_in_ns(struct trace_array *tr)
+{
+	if (trace_clocks[tr->clock_id].in_ns)
+		return true;
+
+	return false;
+}
+
+/*
+ * trace_parser_get_init - gets the buffer for trace parser
+ */
+int trace_parser_get_init(struct trace_parser *parser, int size)
+{
+	memset(parser, 0, sizeof(*parser));
+
+	parser->buffer = kmalloc(size, GFP_KERNEL);
+	if (!parser->buffer)
+		return 1;
+
+	parser->size = size;
+	return 0;
+}
+
+/*
+ * trace_parser_put - frees the buffer for trace parser
+ */
+void trace_parser_put(struct trace_parser *parser)
+{
+	kfree(parser->buffer);
+	parser->buffer = NULL;
+}
+
+/*
+ * trace_get_user - reads the user input string separated by  space
+ * (matched by isspace(ch))
+ *
+ * For each string found the 'struct trace_parser' is updated,
+ * and the function returns.
+ *
+ * Returns number of bytes read.
+ *
+ * See kernel/trace/trace.h for 'struct trace_parser' details.
+ */
+int trace_get_user(struct trace_parser *parser, const char __user *ubuf,
+	size_t cnt, loff_t *ppos)
+{
+	char ch;
+	size_t read = 0;
+	ssize_t ret;
+
+	if (!*ppos)
+		trace_parser_clear(parser);
+
+	ret = get_user(ch, ubuf++);
+	if (ret)
+		goto out;
+
+	read++;
+	cnt--;
+
+	/*
+	 * The parser is not finished with the last write,
+	 * continue reading the user input without skipping spaces.
+	 */
+	if (!parser->cont) {
+		/* skip white space */
+		while (cnt && isspace(ch)) {
+			ret = get_user(ch, ubuf++);
+			if (ret)
+				goto out;
+			read++;
+			cnt--;
+		}
+
+		parser->idx = 0;
+
+		/* only spaces were written */
+		if (isspace(ch) || !ch) {
+			*ppos += read;
+			ret = read;
+			goto out;
+		}
+	}
+
+	/* read the non-space input */
+	while (cnt && !isspace(ch) && ch) {
+		if (parser->idx < parser->size - 1)
+			parser->buffer[parser->idx++] = ch;
+		else {
+			ret = -EINVAL;
+			goto out;
+		}
+		ret = get_user(ch, ubuf++);
+		if (ret)
+			goto out;
+		read++;
+		cnt--;
+	}
+
+	/* We either got finished input or we have to wait for another call. */
+	if (isspace(ch) || !ch) {
+		parser->buffer[parser->idx] = 0;
+		parser->cont = false;
+	} else if (parser->idx < parser->size - 1) {
+		parser->cont = true;
+		parser->buffer[parser->idx++] = ch;
+		/* Make sure the parsed string always terminates with '\0'. */
+		parser->buffer[parser->idx] = 0;
+	} else {
+		ret = -EINVAL;
+		goto out;
+	}
+
+	*ppos += read;
+	ret = read;
+
+out:
+	return ret;
+}
+
+/* TODO add a seq_buf_to_buffer() */
+static ssize_t trace_seq_to_buffer(struct trace_seq *s, void *buf, size_t cnt)
+{
+	int len;
+
+	if (trace_seq_used(s) <= s->seq.readpos)
+		return -EBUSY;
+
+	len = trace_seq_used(s) - s->seq.readpos;
+	if (cnt > len)
+		cnt = len;
+	memcpy(buf, s->buffer + s->seq.readpos, cnt);
+
+	s->seq.readpos += cnt;
+	return cnt;
+}
+
+unsigned long __read_mostly	tracing_thresh;
+
+#ifdef CONFIG_TRACER_MAX_TRACE
+/*
+ * Copy the new maximum trace into the separate maximum-trace
+ * structure. (this way the maximum trace is permanently saved,
+ * for later retrieval via /sys/kernel/tracing/tracing_max_latency)
+ */
+static void
+__update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu)
+{
+	struct trace_buffer *trace_buf = &tr->trace_buffer;
+	struct trace_buffer *max_buf = &tr->max_buffer;
+	struct trace_array_cpu *data = per_cpu_ptr(trace_buf->data, cpu);
+	struct trace_array_cpu *max_data = per_cpu_ptr(max_buf->data, cpu);
+
+	max_buf->cpu = cpu;
+	max_buf->time_start = data->preempt_timestamp;
+
+	max_data->saved_latency = tr->max_latency;
+	max_data->critical_start = data->critical_start;
+	max_data->critical_end = data->critical_end;
+
+	memcpy(max_data->comm, tsk->comm, TASK_COMM_LEN);
+	max_data->pid = tsk->pid;
+	/*
+	 * If tsk == current, then use current_uid(), as that does not use
+	 * RCU. The irq tracer can be called out of RCU scope.
+	 */
+	if (tsk == current)
+		max_data->uid = current_uid();
+	else
+		max_data->uid = task_uid(tsk);
+
+	max_data->nice = tsk->static_prio - 20 - MAX_RT_PRIO;
+	max_data->policy = tsk->policy;
+	max_data->rt_priority = tsk->rt_priority;
+
+	/* record this tasks comm */
+	tracing_record_cmdline(tsk);
+}
+
+/**
+ * update_max_tr - snapshot all trace buffers from global_trace to max_tr
+ * @tr: tracer
+ * @tsk: the task with the latency
+ * @cpu: The cpu that initiated the trace.
+ *
+ * Flip the buffers between the @tr and the max_tr and record information
+ * about which task was the cause of this latency.
+ */
+void
+update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu)
+{
+	if (tr->stop_count)
+		return;
+
+	WARN_ON_ONCE(!irqs_disabled());
+
+	if (!tr->allocated_snapshot) {
+		/* Only the nop tracer should hit this when disabling */
+		WARN_ON_ONCE(tr->current_trace != &nop_trace);
+		return;
+	}
+
+	arch_spin_lock(&tr->max_lock);
+
+	/* Inherit the recordable setting from trace_buffer */
+	if (ring_buffer_record_is_set_on(tr->trace_buffer.buffer))
+		ring_buffer_record_on(tr->max_buffer.buffer);
+	else
+		ring_buffer_record_off(tr->max_buffer.buffer);
+
+	swap(tr->trace_buffer.buffer, tr->max_buffer.buffer);
+
+	__update_max_tr(tr, tsk, cpu);
+	arch_spin_unlock(&tr->max_lock);
+}
+
+/**
+ * update_max_tr_single - only copy one trace over, and reset the rest
+ * @tr - tracer
+ * @tsk - task with the latency
+ * @cpu - the cpu of the buffer to copy.
+ *
+ * Flip the trace of a single CPU buffer between the @tr and the max_tr.
+ */
+void
+update_max_tr_single(struct trace_array *tr, struct task_struct *tsk, int cpu)
+{
+	int ret;
+
+	if (tr->stop_count)
+		return;
+
+	WARN_ON_ONCE(!irqs_disabled());
+	if (!tr->allocated_snapshot) {
+		/* Only the nop tracer should hit this when disabling */
+		WARN_ON_ONCE(tr->current_trace != &nop_trace);
+		return;
+	}
+
+	arch_spin_lock(&tr->max_lock);
+
+	ret = ring_buffer_swap_cpu(tr->max_buffer.buffer, tr->trace_buffer.buffer, cpu);
+
+	if (ret == -EBUSY) {
+		/*
+		 * We failed to swap the buffer due to a commit taking
+		 * place on this CPU. We fail to record, but we reset
+		 * the max trace buffer (no one writes directly to it)
+		 * and flag that it failed.
+		 */
+		trace_array_printk_buf(tr->max_buffer.buffer, _THIS_IP_,
+			"Failed to swap buffers due to commit in progress\n");
+	}
+
+	WARN_ON_ONCE(ret && ret != -EAGAIN && ret != -EBUSY);
+
+	__update_max_tr(tr, tsk, cpu);
+	arch_spin_unlock(&tr->max_lock);
+}
+#endif /* CONFIG_TRACER_MAX_TRACE */
+
+static int wait_on_pipe(struct trace_iterator *iter, bool full)
+{
+	/* Iterators are static, they should be filled or empty */
+	if (trace_buffer_iter(iter, iter->cpu_file))
+		return 0;
+
+	return ring_buffer_wait(iter->trace_buffer->buffer, iter->cpu_file,
+				full);
+}
+
+#ifdef CONFIG_FTRACE_STARTUP_TEST
+static bool selftests_can_run;
+
+struct trace_selftests {
+	struct list_head		list;
+	struct tracer			*type;
+};
+
+static LIST_HEAD(postponed_selftests);
+
+static int save_selftest(struct tracer *type)
+{
+	struct trace_selftests *selftest;
+
+	selftest = kmalloc(sizeof(*selftest), GFP_KERNEL);
+	if (!selftest)
+		return -ENOMEM;
+
+	selftest->type = type;
+	list_add(&selftest->list, &postponed_selftests);
+	return 0;
+}
+
+static int run_tracer_selftest(struct tracer *type)
+{
+	struct trace_array *tr = &global_trace;
+	struct tracer *saved_tracer = tr->current_trace;
+	int ret;
+
+	if (!type->selftest || tracing_selftest_disabled)
+		return 0;
+
+	/*
+	 * If a tracer registers early in boot up (before scheduling is
+	 * initialized and such), then do not run its selftests yet.
+	 * Instead, run it a little later in the boot process.
+	 */
+	if (!selftests_can_run)
+		return save_selftest(type);
+
+	/*
+	 * Run a selftest on this tracer.
+	 * Here we reset the trace buffer, and set the current
+	 * tracer to be this tracer. The tracer can then run some
+	 * internal tracing to verify that everything is in order.
+	 * If we fail, we do not register this tracer.
+	 */
+	tracing_reset_online_cpus(&tr->trace_buffer);
+
+	tr->current_trace = type;
+
+#ifdef CONFIG_TRACER_MAX_TRACE
+	if (type->use_max_tr) {
+		/* If we expanded the buffers, make sure the max is expanded too */
+		if (ring_buffer_expanded)
+			ring_buffer_resize(tr->max_buffer.buffer, trace_buf_size,
+					   RING_BUFFER_ALL_CPUS);
+		tr->allocated_snapshot = true;
+	}
+#endif
+
+	/* the test is responsible for initializing and enabling */
+	pr_info("Testing tracer %s: ", type->name);
+	ret = type->selftest(type, tr);
+	/* the test is responsible for resetting too */
+	tr->current_trace = saved_tracer;
+	if (ret) {
+		printk(KERN_CONT "FAILED!\n");
+		/* Add the warning after printing 'FAILED' */
+		WARN_ON(1);
+		return -1;
+	}
+	/* Only reset on passing, to avoid touching corrupted buffers */
+	tracing_reset_online_cpus(&tr->trace_buffer);
+
+#ifdef CONFIG_TRACER_MAX_TRACE
+	if (type->use_max_tr) {
+		tr->allocated_snapshot = false;
+
+		/* Shrink the max buffer again */
+		if (ring_buffer_expanded)
+			ring_buffer_resize(tr->max_buffer.buffer, 1,
+					   RING_BUFFER_ALL_CPUS);
+	}
+#endif
+
+	printk(KERN_CONT "PASSED\n");
+	return 0;
+}
+
+static __init int init_trace_selftests(void)
+{
+	struct trace_selftests *p, *n;
+	struct tracer *t, **last;
+	int ret;
+
+	selftests_can_run = true;
+
+	mutex_lock(&trace_types_lock);
+
+	if (list_empty(&postponed_selftests))
+		goto out;
+
+	pr_info("Running postponed tracer tests:\n");
+
+	tracing_selftest_running = true;
+	list_for_each_entry_safe(p, n, &postponed_selftests, list) {
+		ret = run_tracer_selftest(p->type);
+		/* If the test fails, then warn and remove from available_tracers */
+		if (ret < 0) {
+			WARN(1, "tracer: %s failed selftest, disabling\n",
+			     p->type->name);
+			last = &trace_types;
+			for (t = trace_types; t; t = t->next) {
+				if (t == p->type) {
+					*last = t->next;
+					break;
+				}
+				last = &t->next;
+			}
+		}
+		list_del(&p->list);
+		kfree(p);
+	}
+	tracing_selftest_running = false;
+
+ out:
+	mutex_unlock(&trace_types_lock);
+
+	return 0;
+}
+core_initcall(init_trace_selftests);
+#else
+static inline int run_tracer_selftest(struct tracer *type)
+{
+	return 0;
+}
+#endif /* CONFIG_FTRACE_STARTUP_TEST */
+
+static void add_tracer_options(struct trace_array *tr, struct tracer *t);
+
+static void __init apply_trace_boot_options(void);
+
+/**
+ * register_tracer - register a tracer with the ftrace system.
+ * @type - the plugin for the tracer
+ *
+ * Register a new plugin tracer.
+ */
+int __init register_tracer(struct tracer *type)
+{
+	struct tracer *t;
+	int ret = 0;
+
+	if (!type->name) {
+		pr_info("Tracer must have a name\n");
+		return -1;
+	}
+
+	if (strlen(type->name) >= MAX_TRACER_SIZE) {
+		pr_info("Tracer has a name longer than %d\n", MAX_TRACER_SIZE);
+		return -1;
+	}
+
+	mutex_lock(&trace_types_lock);
+
+	tracing_selftest_running = true;
+
+	for (t = trace_types; t; t = t->next) {
+		if (strcmp(type->name, t->name) == 0) {
+			/* already found */
+			pr_info("Tracer %s already registered\n",
+				type->name);
+			ret = -1;
+			goto out;
+		}
+	}
+
+	if (!type->set_flag)
+		type->set_flag = &dummy_set_flag;
+	if (!type->flags) {
+		/*allocate a dummy tracer_flags*/
+		type->flags = kmalloc(sizeof(*type->flags), GFP_KERNEL);
+		if (!type->flags) {
+			ret = -ENOMEM;
+			goto out;
+		}
+		type->flags->val = 0;
+		type->flags->opts = dummy_tracer_opt;
+	} else
+		if (!type->flags->opts)
+			type->flags->opts = dummy_tracer_opt;
+
+	/* store the tracer for __set_tracer_option */
+	type->flags->trace = type;
+
+	ret = run_tracer_selftest(type);
+	if (ret < 0)
+		goto out;
+
+	type->next = trace_types;
+	trace_types = type;
+	add_tracer_options(&global_trace, type);
+
+ out:
+	tracing_selftest_running = false;
+	mutex_unlock(&trace_types_lock);
+
+	if (ret || !default_bootup_tracer)
+		goto out_unlock;
+
+	if (strncmp(default_bootup_tracer, type->name, MAX_TRACER_SIZE))
+		goto out_unlock;
+
+	printk(KERN_INFO "Starting tracer '%s'\n", type->name);
+	/* Do we want this tracer to start on bootup? */
+	tracing_set_tracer(&global_trace, type->name);
+	default_bootup_tracer = NULL;
+
+	apply_trace_boot_options();
+
+	/* disable other selftests, since this will break it. */
+	tracing_selftest_disabled = true;
+#ifdef CONFIG_FTRACE_STARTUP_TEST
+	printk(KERN_INFO "Disabling FTRACE selftests due to running tracer '%s'\n",
+	       type->name);
+#endif
+
+ out_unlock:
+	return ret;
+}
+
+void tracing_reset(struct trace_buffer *buf, int cpu)
+{
+	struct ring_buffer *buffer = buf->buffer;
+
+	if (!buffer)
+		return;
+
+	ring_buffer_record_disable(buffer);
+
+	/* Make sure all commits have finished */
+	synchronize_sched();
+	ring_buffer_reset_cpu(buffer, cpu);
+
+	ring_buffer_record_enable(buffer);
+}
+
+void tracing_reset_online_cpus(struct trace_buffer *buf)
+{
+	struct ring_buffer *buffer = buf->buffer;
+	int cpu;
+
+	if (!buffer)
+		return;
+
+	ring_buffer_record_disable(buffer);
+
+	/* Make sure all commits have finished */
+	synchronize_sched();
+
+	buf->time_start = buffer_ftrace_now(buf, buf->cpu);
+
+	for_each_online_cpu(cpu)
+		ring_buffer_reset_cpu(buffer, cpu);
+
+	ring_buffer_record_enable(buffer);
+}
+
+/* Must have trace_types_lock held */
+void tracing_reset_all_online_cpus(void)
+{
+	struct trace_array *tr;
+
+	list_for_each_entry(tr, &ftrace_trace_arrays, list) {
+		if (!tr->clear_trace)
+			continue;
+		tr->clear_trace = false;
+		tracing_reset_online_cpus(&tr->trace_buffer);
+#ifdef CONFIG_TRACER_MAX_TRACE
+		tracing_reset_online_cpus(&tr->max_buffer);
+#endif
+	}
+}
+
+/*
+ * The tgid_map array maps from pid to tgid; i.e. the value stored at index i
+ * is the tgid last observed corresponding to pid=i.
+ */
+static int *tgid_map;
+
+/* The maximum valid index into tgid_map. */
+static size_t tgid_map_max;
+
+#define SAVED_CMDLINES_DEFAULT 128
+#define NO_CMDLINE_MAP UINT_MAX
+static arch_spinlock_t trace_cmdline_lock = __ARCH_SPIN_LOCK_UNLOCKED;
+struct saved_cmdlines_buffer {
+	unsigned map_pid_to_cmdline[PID_MAX_DEFAULT+1];
+	unsigned *map_cmdline_to_pid;
+	unsigned cmdline_num;
+	int cmdline_idx;
+	char *saved_cmdlines;
+};
+static struct saved_cmdlines_buffer *savedcmd;
+
+static inline char *get_saved_cmdlines(int idx)
+{
+	return &savedcmd->saved_cmdlines[idx * TASK_COMM_LEN];
+}
+
+static inline void set_cmdline(int idx, const char *cmdline)
+{
+	memcpy(get_saved_cmdlines(idx), cmdline, TASK_COMM_LEN);
+}
+
+static int allocate_cmdlines_buffer(unsigned int val,
+				    struct saved_cmdlines_buffer *s)
+{
+	s->map_cmdline_to_pid = kmalloc_array(val,
+					      sizeof(*s->map_cmdline_to_pid),
+					      GFP_KERNEL);
+	if (!s->map_cmdline_to_pid)
+		return -ENOMEM;
+
+	s->saved_cmdlines = kmalloc_array(TASK_COMM_LEN, val, GFP_KERNEL);
+	if (!s->saved_cmdlines) {
+		kfree(s->map_cmdline_to_pid);
+		return -ENOMEM;
+	}
+
+	s->cmdline_idx = 0;
+	s->cmdline_num = val;
+	memset(&s->map_pid_to_cmdline, NO_CMDLINE_MAP,
+	       sizeof(s->map_pid_to_cmdline));
+	memset(s->map_cmdline_to_pid, NO_CMDLINE_MAP,
+	       val * sizeof(*s->map_cmdline_to_pid));
+
+	return 0;
+}
+
+static int trace_create_savedcmd(void)
+{
+	int ret;
+
+	savedcmd = kmalloc(sizeof(*savedcmd), GFP_KERNEL);
+	if (!savedcmd)
+		return -ENOMEM;
+
+	ret = allocate_cmdlines_buffer(SAVED_CMDLINES_DEFAULT, savedcmd);
+	if (ret < 0) {
+		kfree(savedcmd);
+		savedcmd = NULL;
+		return -ENOMEM;
+	}
+
+	return 0;
+}
+
+int is_tracing_stopped(void)
+{
+	return global_trace.stop_count;
+}
+
+/**
+ * tracing_start - quick start of the tracer
+ *
+ * If tracing is enabled but was stopped by tracing_stop,
+ * this will start the tracer back up.
+ */
+void tracing_start(void)
+{
+	struct ring_buffer *buffer;
+	unsigned long flags;
+
+	if (tracing_disabled)
+		return;
+
+	raw_spin_lock_irqsave(&global_trace.start_lock, flags);
+	if (--global_trace.stop_count) {
+		if (global_trace.stop_count < 0) {
+			/* Someone screwed up their debugging */
+			WARN_ON_ONCE(1);
+			global_trace.stop_count = 0;
+		}
+		goto out;
+	}
+
+	/* Prevent the buffers from switching */
+	arch_spin_lock(&global_trace.max_lock);
+
+	buffer = global_trace.trace_buffer.buffer;
+	if (buffer)
+		ring_buffer_record_enable(buffer);
+
+#ifdef CONFIG_TRACER_MAX_TRACE
+	buffer = global_trace.max_buffer.buffer;
+	if (buffer)
+		ring_buffer_record_enable(buffer);
+#endif
+
+	arch_spin_unlock(&global_trace.max_lock);
+
+ out:
+	raw_spin_unlock_irqrestore(&global_trace.start_lock, flags);
+}
+
+static void tracing_start_tr(struct trace_array *tr)
+{
+	struct ring_buffer *buffer;
+	unsigned long flags;
+
+	if (tracing_disabled)
+		return;
+
+	/* If global, we need to also start the max tracer */
+	if (tr->flags & TRACE_ARRAY_FL_GLOBAL)
+		return tracing_start();
+
+	raw_spin_lock_irqsave(&tr->start_lock, flags);
+
+	if (--tr->stop_count) {
+		if (tr->stop_count < 0) {
+			/* Someone screwed up their debugging */
+			WARN_ON_ONCE(1);
+			tr->stop_count = 0;
+		}
+		goto out;
+	}
+
+	buffer = tr->trace_buffer.buffer;
+	if (buffer)
+		ring_buffer_record_enable(buffer);
+
+ out:
+	raw_spin_unlock_irqrestore(&tr->start_lock, flags);
+}
+
+/**
+ * tracing_stop - quick stop of the tracer
+ *
+ * Light weight way to stop tracing. Use in conjunction with
+ * tracing_start.
+ */
+void tracing_stop(void)
+{
+	struct ring_buffer *buffer;
+	unsigned long flags;
+
+	raw_spin_lock_irqsave(&global_trace.start_lock, flags);
+	if (global_trace.stop_count++)
+		goto out;
+
+	/* Prevent the buffers from switching */
+	arch_spin_lock(&global_trace.max_lock);
+
+	buffer = global_trace.trace_buffer.buffer;
+	if (buffer)
+		ring_buffer_record_disable(buffer);
+
+#ifdef CONFIG_TRACER_MAX_TRACE
+	buffer = global_trace.max_buffer.buffer;
+	if (buffer)
+		ring_buffer_record_disable(buffer);
+#endif
+
+	arch_spin_unlock(&global_trace.max_lock);
+
+ out:
+	raw_spin_unlock_irqrestore(&global_trace.start_lock, flags);
+}
+
+static void tracing_stop_tr(struct trace_array *tr)
+{
+	struct ring_buffer *buffer;
+	unsigned long flags;
+
+	/* If global, we need to also stop the max tracer */
+	if (tr->flags & TRACE_ARRAY_FL_GLOBAL)
+		return tracing_stop();
+
+	raw_spin_lock_irqsave(&tr->start_lock, flags);
+	if (tr->stop_count++)
+		goto out;
+
+	buffer = tr->trace_buffer.buffer;
+	if (buffer)
+		ring_buffer_record_disable(buffer);
+
+ out:
+	raw_spin_unlock_irqrestore(&tr->start_lock, flags);
+}
+
+static int trace_save_cmdline(struct task_struct *tsk)
+{
+	unsigned tpid, idx;
+
+	/* treat recording of idle task as a success */
+	if (!tsk->pid)
+		return 1;
+
+	tpid = tsk->pid & (PID_MAX_DEFAULT - 1);
+
+	/*
+	 * It's not the end of the world if we don't get
+	 * the lock, but we also don't want to spin
+	 * nor do we want to disable interrupts,
+	 * so if we miss here, then better luck next time.
+	 */
+	if (!arch_spin_trylock(&trace_cmdline_lock))
+		return 0;
+
+	idx = savedcmd->map_pid_to_cmdline[tpid];
+	if (idx == NO_CMDLINE_MAP) {
+		idx = (savedcmd->cmdline_idx + 1) % savedcmd->cmdline_num;
+
+		savedcmd->map_pid_to_cmdline[tpid] = idx;
+		savedcmd->cmdline_idx = idx;
+	}
+
+	savedcmd->map_cmdline_to_pid[idx] = tsk->pid;
+	set_cmdline(idx, tsk->comm);
+
+	arch_spin_unlock(&trace_cmdline_lock);
+
+	return 1;
+}
+
+static void __trace_find_cmdline(int pid, char comm[])
+{
+	unsigned map;
+	int tpid;
+
+	if (!pid) {
+		strcpy(comm, "<idle>");
+		return;
+	}
+
+	if (WARN_ON_ONCE(pid < 0)) {
+		strcpy(comm, "<XXX>");
+		return;
+	}
+
+	tpid = pid & (PID_MAX_DEFAULT - 1);
+	map = savedcmd->map_pid_to_cmdline[tpid];
+	if (map != NO_CMDLINE_MAP) {
+		tpid = savedcmd->map_cmdline_to_pid[map];
+		if (tpid == pid) {
+			strlcpy(comm, get_saved_cmdlines(map), TASK_COMM_LEN);
+			return;
+		}
+	}
+	strcpy(comm, "<...>");
+}
+
+void trace_find_cmdline(int pid, char comm[])
+{
+	preempt_disable();
+	arch_spin_lock(&trace_cmdline_lock);
+
+	__trace_find_cmdline(pid, comm);
+
+	arch_spin_unlock(&trace_cmdline_lock);
+	preempt_enable();
+}
+
+static int *trace_find_tgid_ptr(int pid)
+{
+	/*
+	 * Pairs with the smp_store_release in set_tracer_flag() to ensure that
+	 * if we observe a non-NULL tgid_map then we also observe the correct
+	 * tgid_map_max.
+	 */
+	int *map = smp_load_acquire(&tgid_map);
+
+	if (unlikely(!map || pid > tgid_map_max))
+		return NULL;
+
+	return &map[pid];
+}
+
+int trace_find_tgid(int pid)
+{
+	int *ptr = trace_find_tgid_ptr(pid);
+
+	return ptr ? *ptr : 0;
+}
+
+static int trace_save_tgid(struct task_struct *tsk)
+{
+	int *ptr;
+
+	/* treat recording of idle task as a success */
+	if (!tsk->pid)
+		return 1;
+
+	ptr = trace_find_tgid_ptr(tsk->pid);
+	if (!ptr)
+		return 0;
+
+	*ptr = tsk->tgid;
+	return 1;
+}
+
+static bool tracing_record_taskinfo_skip(int flags)
+{
+	if (unlikely(!(flags & (TRACE_RECORD_CMDLINE | TRACE_RECORD_TGID))))
+		return true;
+	if (!__this_cpu_read(trace_taskinfo_save))
+		return true;
+	return false;
+}
+
+/**
+ * tracing_record_taskinfo - record the task info of a task
+ *
+ * @task  - task to record
+ * @flags - TRACE_RECORD_CMDLINE for recording comm
+ *        - TRACE_RECORD_TGID for recording tgid
+ */
+void tracing_record_taskinfo(struct task_struct *task, int flags)
+{
+	bool done;
+
+	if (tracing_record_taskinfo_skip(flags))
+		return;
+
+	/*
+	 * Record as much task information as possible. If some fail, continue
+	 * to try to record the others.
+	 */
+	done = !(flags & TRACE_RECORD_CMDLINE) || trace_save_cmdline(task);
+	done &= !(flags & TRACE_RECORD_TGID) || trace_save_tgid(task);
+
+	/* If recording any information failed, retry again soon. */
+	if (!done)
+		return;
+
+	__this_cpu_write(trace_taskinfo_save, false);
+}
+
+/**
+ * tracing_record_taskinfo_sched_switch - record task info for sched_switch
+ *
+ * @prev - previous task during sched_switch
+ * @next - next task during sched_switch
+ * @flags - TRACE_RECORD_CMDLINE for recording comm
+ *          TRACE_RECORD_TGID for recording tgid
+ */
+void tracing_record_taskinfo_sched_switch(struct task_struct *prev,
+					  struct task_struct *next, int flags)
+{
+	bool done;
+
+	if (tracing_record_taskinfo_skip(flags))
+		return;
+
+	/*
+	 * Record as much task information as possible. If some fail, continue
+	 * to try to record the others.
+	 */
+	done  = !(flags & TRACE_RECORD_CMDLINE) || trace_save_cmdline(prev);
+	done &= !(flags & TRACE_RECORD_CMDLINE) || trace_save_cmdline(next);
+	done &= !(flags & TRACE_RECORD_TGID) || trace_save_tgid(prev);
+	done &= !(flags & TRACE_RECORD_TGID) || trace_save_tgid(next);
+
+	/* If recording any information failed, retry again soon. */
+	if (!done)
+		return;
+
+	__this_cpu_write(trace_taskinfo_save, false);
+}
+
+/* Helpers to record a specific task information */
+void tracing_record_cmdline(struct task_struct *task)
+{
+	tracing_record_taskinfo(task, TRACE_RECORD_CMDLINE);
+}
+
+void tracing_record_tgid(struct task_struct *task)
+{
+	tracing_record_taskinfo(task, TRACE_RECORD_TGID);
+}
+
+/*
+ * Several functions return TRACE_TYPE_PARTIAL_LINE if the trace_seq
+ * overflowed, and TRACE_TYPE_HANDLED otherwise. This helper function
+ * simplifies those functions and keeps them in sync.
+ */
+enum print_line_t trace_handle_return(struct trace_seq *s)
+{
+	return trace_seq_has_overflowed(s) ?
+		TRACE_TYPE_PARTIAL_LINE : TRACE_TYPE_HANDLED;
+}
+EXPORT_SYMBOL_GPL(trace_handle_return);
+
+void
+tracing_generic_entry_update(struct trace_entry *entry, unsigned long flags,
+			     int pc)
+{
+	struct task_struct *tsk = current;
+
+	entry->preempt_count		= pc & 0xff;
+	entry->pid			= (tsk) ? tsk->pid : 0;
+	entry->flags =
+#ifdef CONFIG_TRACE_IRQFLAGS_SUPPORT
+		(irqs_disabled_flags(flags) ? TRACE_FLAG_IRQS_OFF : 0) |
+#else
+		TRACE_FLAG_IRQS_NOSUPPORT |
+#endif
+		((pc & NMI_MASK    ) ? TRACE_FLAG_NMI     : 0) |
+		((pc & HARDIRQ_MASK) ? TRACE_FLAG_HARDIRQ : 0) |
+		((pc & SOFTIRQ_OFFSET) ? TRACE_FLAG_SOFTIRQ : 0) |
+		(tif_need_resched() ? TRACE_FLAG_NEED_RESCHED : 0) |
+		(test_preempt_need_resched() ? TRACE_FLAG_PREEMPT_RESCHED : 0);
+}
+EXPORT_SYMBOL_GPL(tracing_generic_entry_update);
+
+struct ring_buffer_event *
+trace_buffer_lock_reserve(struct ring_buffer *buffer,
+			  int type,
+			  unsigned long len,
+			  unsigned long flags, int pc)
+{
+	return __trace_buffer_lock_reserve(buffer, type, len, flags, pc);
+}
+
+DEFINE_PER_CPU(struct ring_buffer_event *, trace_buffered_event);
+DEFINE_PER_CPU(int, trace_buffered_event_cnt);
+static int trace_buffered_event_ref;
+
+/**
+ * trace_buffered_event_enable - enable buffering events
+ *
+ * When events are being filtered, it is quicker to use a temporary
+ * buffer to write the event data into if there's a likely chance
+ * that it will not be committed. The discard of the ring buffer
+ * is not as fast as committing, and is much slower than copying
+ * a commit.
+ *
+ * When an event is to be filtered, allocate per cpu buffers to
+ * write the event data into, and if the event is filtered and discarded
+ * it is simply dropped, otherwise, the entire data is to be committed
+ * in one shot.
+ */
+void trace_buffered_event_enable(void)
+{
+	struct ring_buffer_event *event;
+	struct page *page;
+	int cpu;
+
+	WARN_ON_ONCE(!mutex_is_locked(&event_mutex));
+
+	if (trace_buffered_event_ref++)
+		return;
+
+	for_each_tracing_cpu(cpu) {
+		page = alloc_pages_node(cpu_to_node(cpu),
+					GFP_KERNEL | __GFP_NORETRY, 0);
+		if (!page)
+			goto failed;
+
+		event = page_address(page);
+		memset(event, 0, sizeof(*event));
+
+		per_cpu(trace_buffered_event, cpu) = event;
+
+		preempt_disable();
+		if (cpu == smp_processor_id() &&
+		    this_cpu_read(trace_buffered_event) !=
+		    per_cpu(trace_buffered_event, cpu))
+			WARN_ON_ONCE(1);
+		preempt_enable();
+	}
+
+	return;
+ failed:
+	trace_buffered_event_disable();
+}
+
+static void enable_trace_buffered_event(void *data)
+{
+	/* Probably not needed, but do it anyway */
+	smp_rmb();
+	this_cpu_dec(trace_buffered_event_cnt);
+}
+
+static void disable_trace_buffered_event(void *data)
+{
+	this_cpu_inc(trace_buffered_event_cnt);
+}
+
+/**
+ * trace_buffered_event_disable - disable buffering events
+ *
+ * When a filter is removed, it is faster to not use the buffered
+ * events, and to commit directly into the ring buffer. Free up
+ * the temp buffers when there are no more users. This requires
+ * special synchronization with current events.
+ */
+void trace_buffered_event_disable(void)
+{
+	int cpu;
+
+	WARN_ON_ONCE(!mutex_is_locked(&event_mutex));
+
+	if (WARN_ON_ONCE(!trace_buffered_event_ref))
+		return;
+
+	if (--trace_buffered_event_ref)
+		return;
+
+	preempt_disable();
+	/* For each CPU, set the buffer as used. */
+	smp_call_function_many(tracing_buffer_mask,
+			       disable_trace_buffered_event, NULL, 1);
+	preempt_enable();
+
+	/* Wait for all current users to finish */
+	synchronize_sched();
+
+	for_each_tracing_cpu(cpu) {
+		free_page((unsigned long)per_cpu(trace_buffered_event, cpu));
+		per_cpu(trace_buffered_event, cpu) = NULL;
+	}
+	/*
+	 * Make sure trace_buffered_event is NULL before clearing
+	 * trace_buffered_event_cnt.
+	 */
+	smp_wmb();
+
+	preempt_disable();
+	/* Do the work on each cpu */
+	smp_call_function_many(tracing_buffer_mask,
+			       enable_trace_buffered_event, NULL, 1);
+	preempt_enable();
+}
+
+static struct ring_buffer *temp_buffer;
+
+struct ring_buffer_event *
+trace_event_buffer_lock_reserve(struct ring_buffer **current_rb,
+			  struct trace_event_file *trace_file,
+			  int type, unsigned long len,
+			  unsigned long flags, int pc)
+{
+	struct ring_buffer_event *entry;
+	int val;
+
+	*current_rb = trace_file->tr->trace_buffer.buffer;
+
+	if (!ring_buffer_time_stamp_abs(*current_rb) && (trace_file->flags &
+	     (EVENT_FILE_FL_SOFT_DISABLED | EVENT_FILE_FL_FILTERED)) &&
+	    (entry = this_cpu_read(trace_buffered_event))) {
+		/* Try to use the per cpu buffer first */
+		val = this_cpu_inc_return(trace_buffered_event_cnt);
+		if ((len < (PAGE_SIZE - sizeof(*entry) - sizeof(entry->array[0]))) && val == 1) {
+			trace_event_setup(entry, type, flags, pc);
+			entry->array[0] = len;
+			return entry;
+		}
+		this_cpu_dec(trace_buffered_event_cnt);
+	}
+
+	entry = __trace_buffer_lock_reserve(*current_rb,
+					    type, len, flags, pc);
+	/*
+	 * If tracing is off, but we have triggers enabled
+	 * we still need to look at the event data. Use the temp_buffer
+	 * to store the trace event for the tigger to use. It's recusive
+	 * safe and will not be recorded anywhere.
+	 */
+	if (!entry && trace_file->flags & EVENT_FILE_FL_TRIGGER_COND) {
+		*current_rb = temp_buffer;
+		entry = __trace_buffer_lock_reserve(*current_rb,
+						    type, len, flags, pc);
+	}
+	return entry;
+}
+EXPORT_SYMBOL_GPL(trace_event_buffer_lock_reserve);
+
+static DEFINE_RAW_SPINLOCK(tracepoint_iter_lock);
+static DEFINE_MUTEX(tracepoint_printk_mutex);
+
+static void output_printk(struct trace_event_buffer *fbuffer)
+{
+	struct trace_event_call *event_call;
+	struct trace_event *event;
+	unsigned long flags;
+	struct trace_iterator *iter = tracepoint_print_iter;
+
+	/* We should never get here if iter is NULL */
+	if (WARN_ON_ONCE(!iter))
+		return;
+
+	event_call = fbuffer->trace_file->event_call;
+	if (!event_call || !event_call->event.funcs ||
+	    !event_call->event.funcs->trace)
+		return;
+
+	event = &fbuffer->trace_file->event_call->event;
+
+	raw_spin_lock_irqsave(&tracepoint_iter_lock, flags);
+	trace_seq_init(&iter->seq);
+	iter->ent = fbuffer->entry;
+	event_call->event.funcs->trace(iter, 0, event);
+	trace_seq_putc(&iter->seq, 0);
+	printk("%s", iter->seq.buffer);
+
+	raw_spin_unlock_irqrestore(&tracepoint_iter_lock, flags);
+}
+
+int tracepoint_printk_sysctl(struct ctl_table *table, int write,
+			     void __user *buffer, size_t *lenp,
+			     loff_t *ppos)
+{
+	int save_tracepoint_printk;
+	int ret;
+
+	mutex_lock(&tracepoint_printk_mutex);
+	save_tracepoint_printk = tracepoint_printk;
+
+	ret = proc_dointvec(table, write, buffer, lenp, ppos);
+
+	/*
+	 * This will force exiting early, as tracepoint_printk
+	 * is always zero when tracepoint_printk_iter is not allocated
+	 */
+	if (!tracepoint_print_iter)
+		tracepoint_printk = 0;
+
+	if (save_tracepoint_printk == tracepoint_printk)
+		goto out;
+
+	if (tracepoint_printk)
+		static_key_enable(&tracepoint_printk_key.key);
+	else
+		static_key_disable(&tracepoint_printk_key.key);
+
+ out:
+	mutex_unlock(&tracepoint_printk_mutex);
+
+	return ret;
+}
+
+void trace_event_buffer_commit(struct trace_event_buffer *fbuffer)
+{
+	if (static_key_false(&tracepoint_printk_key.key))
+		output_printk(fbuffer);
+
+	event_trigger_unlock_commit(fbuffer->trace_file, fbuffer->buffer,
+				    fbuffer->event, fbuffer->entry,
+				    fbuffer->flags, fbuffer->pc);
+}
+EXPORT_SYMBOL_GPL(trace_event_buffer_commit);
+
+/*
+ * Skip 3:
+ *
+ *   trace_buffer_unlock_commit_regs()
+ *   trace_event_buffer_commit()
+ *   trace_event_raw_event_xxx()
+ */
+# define STACK_SKIP 3
+
+void trace_buffer_unlock_commit_regs(struct trace_array *tr,
+				     struct ring_buffer *buffer,
+				     struct ring_buffer_event *event,
+				     unsigned long flags, int pc,
+				     struct pt_regs *regs)
+{
+	__buffer_unlock_commit(buffer, event);
+
+	/*
+	 * If regs is not set, then skip the necessary functions.
+	 * Note, we can still get here via blktrace, wakeup tracer
+	 * and mmiotrace, but that's ok if they lose a function or
+	 * two. They are not that meaningful.
+	 */
+	ftrace_trace_stack(tr, buffer, flags, regs ? 0 : STACK_SKIP, pc, regs);
+	ftrace_trace_userstack(tr, buffer, flags, pc);
+}
+
+/*
+ * Similar to trace_buffer_unlock_commit_regs() but do not dump stack.
+ */
+void
+trace_buffer_unlock_commit_nostack(struct ring_buffer *buffer,
+				   struct ring_buffer_event *event)
+{
+	__buffer_unlock_commit(buffer, event);
+}
+
+static void
+trace_process_export(struct trace_export *export,
+	       struct ring_buffer_event *event)
+{
+	struct trace_entry *entry;
+	unsigned int size = 0;
+
+	entry = ring_buffer_event_data(event);
+	size = ring_buffer_event_length(event);
+	export->write(export, entry, size);
+}
+
+static DEFINE_MUTEX(ftrace_export_lock);
+
+static struct trace_export __rcu *ftrace_exports_list __read_mostly;
+
+static DEFINE_STATIC_KEY_FALSE(ftrace_exports_enabled);
+
+static inline void ftrace_exports_enable(void)
+{
+	static_branch_enable(&ftrace_exports_enabled);
+}
+
+static inline void ftrace_exports_disable(void)
+{
+	static_branch_disable(&ftrace_exports_enabled);
+}
+
+void ftrace_exports(struct ring_buffer_event *event)
+{
+	struct trace_export *export;
+
+	preempt_disable_notrace();
+
+	export = rcu_dereference_raw_notrace(ftrace_exports_list);
+	while (export) {
+		trace_process_export(export, event);
+		export = rcu_dereference_raw_notrace(export->next);
+	}
+
+	preempt_enable_notrace();
+}
+
+static inline void
+add_trace_export(struct trace_export **list, struct trace_export *export)
+{
+	rcu_assign_pointer(export->next, *list);
+	/*
+	 * We are entering export into the list but another
+	 * CPU might be walking that list. We need to make sure
+	 * the export->next pointer is valid before another CPU sees
+	 * the export pointer included into the list.
+	 */
+	rcu_assign_pointer(*list, export);
+}
+
+static inline int
+rm_trace_export(struct trace_export **list, struct trace_export *export)
+{
+	struct trace_export **p;
+
+	for (p = list; *p != NULL; p = &(*p)->next)
+		if (*p == export)
+			break;
+
+	if (*p != export)
+		return -1;
+
+	rcu_assign_pointer(*p, (*p)->next);
+
+	return 0;
+}
+
+static inline void
+add_ftrace_export(struct trace_export **list, struct trace_export *export)
+{
+	if (*list == NULL)
+		ftrace_exports_enable();
+
+	add_trace_export(list, export);
+}
+
+static inline int
+rm_ftrace_export(struct trace_export **list, struct trace_export *export)
+{
+	int ret;
+
+	ret = rm_trace_export(list, export);
+	if (*list == NULL)
+		ftrace_exports_disable();
+
+	return ret;
+}
+
+int register_ftrace_export(struct trace_export *export)
+{
+	if (WARN_ON_ONCE(!export->write))
+		return -1;
+
+	mutex_lock(&ftrace_export_lock);
+
+	add_ftrace_export(&ftrace_exports_list, export);
+
+	mutex_unlock(&ftrace_export_lock);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(register_ftrace_export);
+
+int unregister_ftrace_export(struct trace_export *export)
+{
+	int ret;
+
+	mutex_lock(&ftrace_export_lock);
+
+	ret = rm_ftrace_export(&ftrace_exports_list, export);
+
+	mutex_unlock(&ftrace_export_lock);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(unregister_ftrace_export);
+
+void
+trace_function(struct trace_array *tr,
+	       unsigned long ip, unsigned long parent_ip, unsigned long flags,
+	       int pc)
+{
+	struct trace_event_call *call = &event_function;
+	struct ring_buffer *buffer = tr->trace_buffer.buffer;
+	struct ring_buffer_event *event;
+	struct ftrace_entry *entry;
+
+	event = __trace_buffer_lock_reserve(buffer, TRACE_FN, sizeof(*entry),
+					    flags, pc);
+	if (!event)
+		return;
+	entry	= ring_buffer_event_data(event);
+	entry->ip			= ip;
+	entry->parent_ip		= parent_ip;
+
+	if (!call_filter_check_discard(call, entry, buffer, event)) {
+		if (static_branch_unlikely(&ftrace_exports_enabled))
+			ftrace_exports(event);
+		__buffer_unlock_commit(buffer, event);
+	}
+}
+
+#ifdef CONFIG_STACKTRACE
+
+#define FTRACE_STACK_MAX_ENTRIES (PAGE_SIZE / sizeof(unsigned long))
+struct ftrace_stack {
+	unsigned long		calls[FTRACE_STACK_MAX_ENTRIES];
+};
+
+static DEFINE_PER_CPU(struct ftrace_stack, ftrace_stack);
+static DEFINE_PER_CPU(int, ftrace_stack_reserve);
+
+static void __ftrace_trace_stack(struct ring_buffer *buffer,
+				 unsigned long flags,
+				 int skip, int pc, struct pt_regs *regs)
+{
+	struct trace_event_call *call = &event_kernel_stack;
+	struct ring_buffer_event *event;
+	struct stack_entry *entry;
+	struct stack_trace trace;
+	int use_stack;
+	int size = FTRACE_STACK_ENTRIES;
+
+	trace.nr_entries	= 0;
+	trace.skip		= skip;
+
+	/*
+	 * Add one, for this function and the call to save_stack_trace()
+	 * If regs is set, then these functions will not be in the way.
+	 */
+#ifndef CONFIG_UNWINDER_ORC
+	if (!regs)
+		trace.skip++;
+#endif
+
+	/*
+	 * Since events can happen in NMIs there's no safe way to
+	 * use the per cpu ftrace_stacks. We reserve it and if an interrupt
+	 * or NMI comes in, it will just have to use the default
+	 * FTRACE_STACK_SIZE.
+	 */
+	preempt_disable_notrace();
+
+	use_stack = __this_cpu_inc_return(ftrace_stack_reserve);
+	/*
+	 * We don't need any atomic variables, just a barrier.
+	 * If an interrupt comes in, we don't care, because it would
+	 * have exited and put the counter back to what we want.
+	 * We just need a barrier to keep gcc from moving things
+	 * around.
+	 */
+	barrier();
+	if (use_stack == 1) {
+		trace.entries		= this_cpu_ptr(ftrace_stack.calls);
+		trace.max_entries	= FTRACE_STACK_MAX_ENTRIES;
+
+		if (regs)
+			save_stack_trace_regs(regs, &trace);
+		else
+			save_stack_trace(&trace);
+
+		if (trace.nr_entries > size)
+			size = trace.nr_entries;
+	} else
+		/* From now on, use_stack is a boolean */
+		use_stack = 0;
+
+	size *= sizeof(unsigned long);
+
+	event = __trace_buffer_lock_reserve(buffer, TRACE_STACK,
+				    (sizeof(*entry) - sizeof(entry->caller)) + size,
+				    flags, pc);
+	if (!event)
+		goto out;
+	entry = ring_buffer_event_data(event);
+
+	memset(&entry->caller, 0, size);
+
+	if (use_stack)
+		memcpy(&entry->caller, trace.entries,
+		       trace.nr_entries * sizeof(unsigned long));
+	else {
+		trace.max_entries	= FTRACE_STACK_ENTRIES;
+		trace.entries		= entry->caller;
+		if (regs)
+			save_stack_trace_regs(regs, &trace);
+		else
+			save_stack_trace(&trace);
+	}
+
+	entry->size = trace.nr_entries;
+
+	if (!call_filter_check_discard(call, entry, buffer, event))
+		__buffer_unlock_commit(buffer, event);
+
+ out:
+	/* Again, don't let gcc optimize things here */
+	barrier();
+	__this_cpu_dec(ftrace_stack_reserve);
+	preempt_enable_notrace();
+
+}
+
+static inline void ftrace_trace_stack(struct trace_array *tr,
+				      struct ring_buffer *buffer,
+				      unsigned long flags,
+				      int skip, int pc, struct pt_regs *regs)
+{
+	if (!(tr->trace_flags & TRACE_ITER_STACKTRACE))
+		return;
+
+	__ftrace_trace_stack(buffer, flags, skip, pc, regs);
+}
+
+void __trace_stack(struct trace_array *tr, unsigned long flags, int skip,
+		   int pc)
+{
+	struct ring_buffer *buffer = tr->trace_buffer.buffer;
+
+	if (rcu_is_watching()) {
+		__ftrace_trace_stack(buffer, flags, skip, pc, NULL);
+		return;
+	}
+
+	/*
+	 * When an NMI triggers, RCU is enabled via rcu_nmi_enter(),
+	 * but if the above rcu_is_watching() failed, then the NMI
+	 * triggered someplace critical, and rcu_irq_enter() should
+	 * not be called from NMI.
+	 */
+	if (unlikely(in_nmi()))
+		return;
+
+	rcu_irq_enter_irqson();
+	__ftrace_trace_stack(buffer, flags, skip, pc, NULL);
+	rcu_irq_exit_irqson();
+}
+
+/**
+ * trace_dump_stack - record a stack back trace in the trace buffer
+ * @skip: Number of functions to skip (helper handlers)
+ */
+void trace_dump_stack(int skip)
+{
+	unsigned long flags;
+
+	if (tracing_disabled || tracing_selftest_running)
+		return;
+
+	local_save_flags(flags);
+
+#ifndef CONFIG_UNWINDER_ORC
+	/* Skip 1 to skip this function. */
+	skip++;
+#endif
+	__ftrace_trace_stack(global_trace.trace_buffer.buffer,
+			     flags, skip, preempt_count(), NULL);
+}
+
+static DEFINE_PER_CPU(int, user_stack_count);
+
+void
+ftrace_trace_userstack(struct trace_array *tr,
+		       struct ring_buffer *buffer, unsigned long flags, int pc)
+{
+	struct trace_event_call *call = &event_user_stack;
+	struct ring_buffer_event *event;
+	struct userstack_entry *entry;
+	struct stack_trace trace;
+
+	if (!(tr->trace_flags & TRACE_ITER_USERSTACKTRACE))
+		return;
+
+	/*
+	 * NMIs can not handle page faults, even with fix ups.
+	 * The save user stack can (and often does) fault.
+	 */
+	if (unlikely(in_nmi()))
+		return;
+
+	/*
+	 * prevent recursion, since the user stack tracing may
+	 * trigger other kernel events.
+	 */
+	preempt_disable();
+	if (__this_cpu_read(user_stack_count))
+		goto out;
+
+	__this_cpu_inc(user_stack_count);
+
+	event = __trace_buffer_lock_reserve(buffer, TRACE_USER_STACK,
+					    sizeof(*entry), flags, pc);
+	if (!event)
+		goto out_drop_count;
+	entry	= ring_buffer_event_data(event);
+
+	entry->tgid		= current->tgid;
+	memset(&entry->caller, 0, sizeof(entry->caller));
+
+	trace.nr_entries	= 0;
+	trace.max_entries	= FTRACE_STACK_ENTRIES;
+	trace.skip		= 0;
+	trace.entries		= entry->caller;
+
+	save_stack_trace_user(&trace);
+	if (!call_filter_check_discard(call, entry, buffer, event))
+		__buffer_unlock_commit(buffer, event);
+
+ out_drop_count:
+	__this_cpu_dec(user_stack_count);
+ out:
+	preempt_enable();
+}
+
+#ifdef UNUSED
+static void __trace_userstack(struct trace_array *tr, unsigned long flags)
+{
+	ftrace_trace_userstack(tr, flags, preempt_count());
+}
+#endif /* UNUSED */
+
+#endif /* CONFIG_STACKTRACE */
+
+/* created for use with alloc_percpu */
+struct trace_buffer_struct {
+	int nesting;
+	char buffer[4][TRACE_BUF_SIZE];
+};
+
+static struct trace_buffer_struct __percpu *trace_percpu_buffer;
+
+/*
+ * Thise allows for lockless recording.  If we're nested too deeply, then
+ * this returns NULL.
+ */
+static char *get_trace_buf(void)
+{
+	struct trace_buffer_struct *buffer = this_cpu_ptr(trace_percpu_buffer);
+
+	if (!trace_percpu_buffer || buffer->nesting >= 4)
+		return NULL;
+
+	buffer->nesting++;
+
+	/* Interrupts must see nesting incremented before we use the buffer */
+	barrier();
+	return &buffer->buffer[buffer->nesting - 1][0];
+}
+
+static void put_trace_buf(void)
+{
+	/* Don't let the decrement of nesting leak before this */
+	barrier();
+	this_cpu_dec(trace_percpu_buffer->nesting);
+}
+
+static int alloc_percpu_trace_buffer(void)
+{
+	struct trace_buffer_struct __percpu *buffers;
+
+	buffers = alloc_percpu(struct trace_buffer_struct);
+	if (WARN(!buffers, "Could not allocate percpu trace_printk buffer"))
+		return -ENOMEM;
+
+	trace_percpu_buffer = buffers;
+	return 0;
+}
+
+static int buffers_allocated;
+
+void trace_printk_init_buffers(void)
+{
+	if (buffers_allocated)
+		return;
+
+	if (alloc_percpu_trace_buffer())
+		return;
+
+	/* trace_printk() is for debug use only. Don't use it in production. */
+
+	pr_warn("\n");
+	pr_warn("**********************************************************\n");
+	pr_warn("**   NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE   **\n");
+	pr_warn("**                                                      **\n");
+	pr_warn("** trace_printk() being used. Allocating extra memory.  **\n");
+	pr_warn("**                                                      **\n");
+	pr_warn("** This means that this is a DEBUG kernel and it is     **\n");
+	pr_warn("** unsafe for production use.                           **\n");
+	pr_warn("**                                                      **\n");
+	pr_warn("** If you see this message and you are not debugging    **\n");
+	pr_warn("** the kernel, report this immediately to your vendor!  **\n");
+	pr_warn("**                                                      **\n");
+	pr_warn("**   NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE NOTICE   **\n");
+	pr_warn("**********************************************************\n");
+
+	/* Expand the buffers to set size */
+	tracing_update_buffers();
+
+	buffers_allocated = 1;
+
+	/*
+	 * trace_printk_init_buffers() can be called by modules.
+	 * If that happens, then we need to start cmdline recording
+	 * directly here. If the global_trace.buffer is already
+	 * allocated here, then this was called by module code.
+	 */
+	if (global_trace.trace_buffer.buffer)
+		tracing_start_cmdline_record();
+}
+
+void trace_printk_start_comm(void)
+{
+	/* Start tracing comms if trace printk is set */
+	if (!buffers_allocated)
+		return;
+	tracing_start_cmdline_record();
+}
+
+static void trace_printk_start_stop_comm(int enabled)
+{
+	if (!buffers_allocated)
+		return;
+
+	if (enabled)
+		tracing_start_cmdline_record();
+	else
+		tracing_stop_cmdline_record();
+}
+
+/**
+ * trace_vbprintk - write binary msg to tracing buffer
+ *
+ */
+int trace_vbprintk(unsigned long ip, const char *fmt, va_list args)
+{
+	struct trace_event_call *call = &event_bprint;
+	struct ring_buffer_event *event;
+	struct ring_buffer *buffer;
+	struct trace_array *tr = &global_trace;
+	struct bprint_entry *entry;
+	unsigned long flags;
+	char *tbuffer;
+	int len = 0, size, pc;
+
+	if (unlikely(tracing_selftest_running || tracing_disabled))
+		return 0;
+
+	/* Don't pollute graph traces with trace_vprintk internals */
+	pause_graph_tracing();
+
+	pc = preempt_count();
+	preempt_disable_notrace();
+
+	tbuffer = get_trace_buf();
+	if (!tbuffer) {
+		len = 0;
+		goto out_nobuffer;
+	}
+
+	len = vbin_printf((u32 *)tbuffer, TRACE_BUF_SIZE/sizeof(int), fmt, args);
+
+	if (len > TRACE_BUF_SIZE/sizeof(int) || len < 0)
+		goto out;
+
+	local_save_flags(flags);
+	size = sizeof(*entry) + sizeof(u32) * len;
+	buffer = tr->trace_buffer.buffer;
+	event = __trace_buffer_lock_reserve(buffer, TRACE_BPRINT, size,
+					    flags, pc);
+	if (!event)
+		goto out;
+	entry = ring_buffer_event_data(event);
+	entry->ip			= ip;
+	entry->fmt			= fmt;
+
+	memcpy(entry->buf, tbuffer, sizeof(u32) * len);
+	if (!call_filter_check_discard(call, entry, buffer, event)) {
+		__buffer_unlock_commit(buffer, event);
+		ftrace_trace_stack(tr, buffer, flags, 6, pc, NULL);
+	}
+
+out:
+	put_trace_buf();
+
+out_nobuffer:
+	preempt_enable_notrace();
+	unpause_graph_tracing();
+
+	return len;
+}
+EXPORT_SYMBOL_GPL(trace_vbprintk);
+
+__printf(3, 0)
+static int
+__trace_array_vprintk(struct ring_buffer *buffer,
+		      unsigned long ip, const char *fmt, va_list args)
+{
+	struct trace_event_call *call = &event_print;
+	struct ring_buffer_event *event;
+	int len = 0, size, pc;
+	struct print_entry *entry;
+	unsigned long flags;
+	char *tbuffer;
+
+	if (tracing_disabled || tracing_selftest_running)
+		return 0;
+
+	/* Don't pollute graph traces with trace_vprintk internals */
+	pause_graph_tracing();
+
+	pc = preempt_count();
+	preempt_disable_notrace();
+
+
+	tbuffer = get_trace_buf();
+	if (!tbuffer) {
+		len = 0;
+		goto out_nobuffer;
+	}
+
+	len = vscnprintf(tbuffer, TRACE_BUF_SIZE, fmt, args);
+
+	local_save_flags(flags);
+	size = sizeof(*entry) + len + 1;
+	event = __trace_buffer_lock_reserve(buffer, TRACE_PRINT, size,
+					    flags, pc);
+	if (!event)
+		goto out;
+	entry = ring_buffer_event_data(event);
+	entry->ip = ip;
+
+	memcpy(&entry->buf, tbuffer, len + 1);
+	if (!call_filter_check_discard(call, entry, buffer, event)) {
+		__buffer_unlock_commit(buffer, event);
+		ftrace_trace_stack(&global_trace, buffer, flags, 6, pc, NULL);
+	}
+
+out:
+	put_trace_buf();
+
+out_nobuffer:
+	preempt_enable_notrace();
+	unpause_graph_tracing();
+
+	return len;
+}
+
+__printf(3, 0)
+int trace_array_vprintk(struct trace_array *tr,
+			unsigned long ip, const char *fmt, va_list args)
+{
+	return __trace_array_vprintk(tr->trace_buffer.buffer, ip, fmt, args);
+}
+
+__printf(3, 0)
+int trace_array_printk(struct trace_array *tr,
+		       unsigned long ip, const char *fmt, ...)
+{
+	int ret;
+	va_list ap;
+
+	if (!(global_trace.trace_flags & TRACE_ITER_PRINTK))
+		return 0;
+
+	if (!tr)
+		return -ENOENT;
+
+	va_start(ap, fmt);
+	ret = trace_array_vprintk(tr, ip, fmt, ap);
+	va_end(ap);
+	return ret;
+}
+
+__printf(3, 4)
+int trace_array_printk_buf(struct ring_buffer *buffer,
+			   unsigned long ip, const char *fmt, ...)
+{
+	int ret;
+	va_list ap;
+
+	if (!(global_trace.trace_flags & TRACE_ITER_PRINTK))
+		return 0;
+
+	va_start(ap, fmt);
+	ret = __trace_array_vprintk(buffer, ip, fmt, ap);
+	va_end(ap);
+	return ret;
+}
+
+__printf(2, 0)
+int trace_vprintk(unsigned long ip, const char *fmt, va_list args)
+{
+	return trace_array_vprintk(&global_trace, ip, fmt, args);
+}
+EXPORT_SYMBOL_GPL(trace_vprintk);
+
+static void trace_iterator_increment(struct trace_iterator *iter)
+{
+	struct ring_buffer_iter *buf_iter = trace_buffer_iter(iter, iter->cpu);
+
+	iter->idx++;
+	if (buf_iter)
+		ring_buffer_read(buf_iter, NULL);
+}
+
+static struct trace_entry *
+peek_next_entry(struct trace_iterator *iter, int cpu, u64 *ts,
+		unsigned long *lost_events)
+{
+	struct ring_buffer_event *event;
+	struct ring_buffer_iter *buf_iter = trace_buffer_iter(iter, cpu);
+
+	if (buf_iter)
+		event = ring_buffer_iter_peek(buf_iter, ts);
+	else
+		event = ring_buffer_peek(iter->trace_buffer->buffer, cpu, ts,
+					 lost_events);
+
+	if (event) {
+		iter->ent_size = ring_buffer_event_length(event);
+		return ring_buffer_event_data(event);
+	}
+	iter->ent_size = 0;
+	return NULL;
+}
+
+static struct trace_entry *
+__find_next_entry(struct trace_iterator *iter, int *ent_cpu,
+		  unsigned long *missing_events, u64 *ent_ts)
+{
+	struct ring_buffer *buffer = iter->trace_buffer->buffer;
+	struct trace_entry *ent, *next = NULL;
+	unsigned long lost_events = 0, next_lost = 0;
+	int cpu_file = iter->cpu_file;
+	u64 next_ts = 0, ts;
+	int next_cpu = -1;
+	int next_size = 0;
+	int cpu;
+
+	/*
+	 * If we are in a per_cpu trace file, don't bother by iterating over
+	 * all cpu and peek directly.
+	 */
+	if (cpu_file > RING_BUFFER_ALL_CPUS) {
+		if (ring_buffer_empty_cpu(buffer, cpu_file))
+			return NULL;
+		ent = peek_next_entry(iter, cpu_file, ent_ts, missing_events);
+		if (ent_cpu)
+			*ent_cpu = cpu_file;
+
+		return ent;
+	}
+
+	for_each_tracing_cpu(cpu) {
+
+		if (ring_buffer_empty_cpu(buffer, cpu))
+			continue;
+
+		ent = peek_next_entry(iter, cpu, &ts, &lost_events);
+
+		/*
+		 * Pick the entry with the smallest timestamp:
+		 */
+		if (ent && (!next || ts < next_ts)) {
+			next = ent;
+			next_cpu = cpu;
+			next_ts = ts;
+			next_lost = lost_events;
+			next_size = iter->ent_size;
+		}
+	}
+
+	iter->ent_size = next_size;
+
+	if (ent_cpu)
+		*ent_cpu = next_cpu;
+
+	if (ent_ts)
+		*ent_ts = next_ts;
+
+	if (missing_events)
+		*missing_events = next_lost;
+
+	return next;
+}
+
+/* Find the next real entry, without updating the iterator itself */
+struct trace_entry *trace_find_next_entry(struct trace_iterator *iter,
+					  int *ent_cpu, u64 *ent_ts)
+{
+	return __find_next_entry(iter, ent_cpu, NULL, ent_ts);
+}
+
+/* Find the next real entry, and increment the iterator to the next entry */
+void *trace_find_next_entry_inc(struct trace_iterator *iter)
+{
+	iter->ent = __find_next_entry(iter, &iter->cpu,
+				      &iter->lost_events, &iter->ts);
+
+	if (iter->ent)
+		trace_iterator_increment(iter);
+
+	return iter->ent ? iter : NULL;
+}
+
+static void trace_consume(struct trace_iterator *iter)
+{
+	ring_buffer_consume(iter->trace_buffer->buffer, iter->cpu, &iter->ts,
+			    &iter->lost_events);
+}
+
+static void *s_next(struct seq_file *m, void *v, loff_t *pos)
+{
+	struct trace_iterator *iter = m->private;
+	int i = (int)*pos;
+	void *ent;
+
+	WARN_ON_ONCE(iter->leftover);
+
+	(*pos)++;
+
+	/* can't go backwards */
+	if (iter->idx > i)
+		return NULL;
+
+	if (iter->idx < 0)
+		ent = trace_find_next_entry_inc(iter);
+	else
+		ent = iter;
+
+	while (ent && iter->idx < i)
+		ent = trace_find_next_entry_inc(iter);
+
+	iter->pos = *pos;
+
+	return ent;
+}
+
+void tracing_iter_reset(struct trace_iterator *iter, int cpu)
+{
+	struct ring_buffer_event *event;
+	struct ring_buffer_iter *buf_iter;
+	unsigned long entries = 0;
+	u64 ts;
+
+	per_cpu_ptr(iter->trace_buffer->data, cpu)->skipped_entries = 0;
+
+	buf_iter = trace_buffer_iter(iter, cpu);
+	if (!buf_iter)
+		return;
+
+	ring_buffer_iter_reset(buf_iter);
+
+	/*
+	 * We could have the case with the max latency tracers
+	 * that a reset never took place on a cpu. This is evident
+	 * by the timestamp being before the start of the buffer.
+	 */
+	while ((event = ring_buffer_iter_peek(buf_iter, &ts))) {
+		if (ts >= iter->trace_buffer->time_start)
+			break;
+		entries++;
+		ring_buffer_read(buf_iter, NULL);
+	}
+
+	per_cpu_ptr(iter->trace_buffer->data, cpu)->skipped_entries = entries;
+}
+
+/*
+ * The current tracer is copied to avoid a global locking
+ * all around.
+ */
+static void *s_start(struct seq_file *m, loff_t *pos)
+{
+	struct trace_iterator *iter = m->private;
+	struct trace_array *tr = iter->tr;
+	int cpu_file = iter->cpu_file;
+	void *p = NULL;
+	loff_t l = 0;
+	int cpu;
+
+	/*
+	 * copy the tracer to avoid using a global lock all around.
+	 * iter->trace is a copy of current_trace, the pointer to the
+	 * name may be used instead of a strcmp(), as iter->trace->name
+	 * will point to the same string as current_trace->name.
+	 */
+	mutex_lock(&trace_types_lock);
+	if (unlikely(tr->current_trace && iter->trace->name != tr->current_trace->name))
+		*iter->trace = *tr->current_trace;
+	mutex_unlock(&trace_types_lock);
+
+#ifdef CONFIG_TRACER_MAX_TRACE
+	if (iter->snapshot && iter->trace->use_max_tr)
+		return ERR_PTR(-EBUSY);
+#endif
+
+	if (*pos != iter->pos) {
+		iter->ent = NULL;
+		iter->cpu = 0;
+		iter->idx = -1;
+
+		if (cpu_file == RING_BUFFER_ALL_CPUS) {
+			for_each_tracing_cpu(cpu)
+				tracing_iter_reset(iter, cpu);
+		} else
+			tracing_iter_reset(iter, cpu_file);
+
+		iter->leftover = 0;
+		for (p = iter; p && l < *pos; p = s_next(m, p, &l))
+			;
+
+	} else {
+		/*
+		 * If we overflowed the seq_file before, then we want
+		 * to just reuse the trace_seq buffer again.
+		 */
+		if (iter->leftover)
+			p = iter;
+		else {
+			l = *pos - 1;
+			p = s_next(m, p, &l);
+		}
+	}
+
+	trace_event_read_lock();
+	trace_access_lock(cpu_file);
+	return p;
+}
+
+static void s_stop(struct seq_file *m, void *p)
+{
+	struct trace_iterator *iter = m->private;
+
+#ifdef CONFIG_TRACER_MAX_TRACE
+	if (iter->snapshot && iter->trace->use_max_tr)
+		return;
+#endif
+
+	trace_access_unlock(iter->cpu_file);
+	trace_event_read_unlock();
+}
+
+static void
+get_total_entries(struct trace_buffer *buf,
+		  unsigned long *total, unsigned long *entries)
+{
+	unsigned long count;
+	int cpu;
+
+	*total = 0;
+	*entries = 0;
+
+	for_each_tracing_cpu(cpu) {
+		count = ring_buffer_entries_cpu(buf->buffer, cpu);
+		/*
+		 * If this buffer has skipped entries, then we hold all
+		 * entries for the trace and we need to ignore the
+		 * ones before the time stamp.
+		 */
+		if (per_cpu_ptr(buf->data, cpu)->skipped_entries) {
+			count -= per_cpu_ptr(buf->data, cpu)->skipped_entries;
+			/* total is the same as the entries */
+			*total += count;
+		} else
+			*total += count +
+				ring_buffer_overrun_cpu(buf->buffer, cpu);
+		*entries += count;
+	}
+}
+
+static void print_lat_help_header(struct seq_file *m)
+{
+	seq_puts(m, "#                  _------=> CPU#            \n"
+		    "#                 / _-----=> irqs-off        \n"
+		    "#                | / _----=> need-resched    \n"
+		    "#                || / _---=> hardirq/softirq \n"
+		    "#                ||| / _--=> preempt-depth   \n"
+		    "#                |||| /     delay            \n"
+		    "#  cmd     pid   ||||| time  |   caller      \n"
+		    "#     \\   /      |||||  \\    |   /         \n");
+}
+
+static void print_event_info(struct trace_buffer *buf, struct seq_file *m)
+{
+	unsigned long total;
+	unsigned long entries;
+
+	get_total_entries(buf, &total, &entries);
+	seq_printf(m, "# entries-in-buffer/entries-written: %lu/%lu   #P:%d\n",
+		   entries, total, num_online_cpus());
+	seq_puts(m, "#\n");
+}
+
+static void print_func_help_header(struct trace_buffer *buf, struct seq_file *m,
+				   unsigned int flags)
+{
+	bool tgid = flags & TRACE_ITER_RECORD_TGID;
+
+	print_event_info(buf, m);
+
+	seq_printf(m, "#           TASK-PID   %s  CPU#   TIMESTAMP  FUNCTION\n", tgid ? "TGID     " : "");
+	seq_printf(m, "#              | |     %s    |       |         |\n",	 tgid ? "  |      " : "");
+}
+
+static void print_func_help_header_irq(struct trace_buffer *buf, struct seq_file *m,
+				       unsigned int flags)
+{
+	bool tgid = flags & TRACE_ITER_RECORD_TGID;
+	const char tgid_space[] = "          ";
+	const char space[] = "  ";
+
+	print_event_info(buf, m);
+
+	seq_printf(m, "#                          %s  _-----=> irqs-off\n",
+		   tgid ? tgid_space : space);
+	seq_printf(m, "#                          %s / _----=> need-resched\n",
+		   tgid ? tgid_space : space);
+	seq_printf(m, "#                          %s| / _---=> hardirq/softirq\n",
+		   tgid ? tgid_space : space);
+	seq_printf(m, "#                          %s|| / _--=> preempt-depth\n",
+		   tgid ? tgid_space : space);
+	seq_printf(m, "#                          %s||| /     delay\n",
+		   tgid ? tgid_space : space);
+	seq_printf(m, "#           TASK-PID %sCPU#  ||||    TIMESTAMP  FUNCTION\n",
+		   tgid ? "   TGID   " : space);
+	seq_printf(m, "#              | |   %s  |   ||||       |         |\n",
+		   tgid ? "     |    " : space);
+}
+
+void
+print_trace_header(struct seq_file *m, struct trace_iterator *iter)
+{
+	unsigned long sym_flags = (global_trace.trace_flags & TRACE_ITER_SYM_MASK);
+	struct trace_buffer *buf = iter->trace_buffer;
+	struct trace_array_cpu *data = per_cpu_ptr(buf->data, buf->cpu);
+	struct tracer *type = iter->trace;
+	unsigned long entries;
+	unsigned long total;
+	const char *name = "preemption";
+
+	name = type->name;
+
+	get_total_entries(buf, &total, &entries);
+
+	seq_printf(m, "# %s latency trace v1.1.5 on %s\n",
+		   name, UTS_RELEASE);
+	seq_puts(m, "# -----------------------------------"
+		 "---------------------------------\n");
+	seq_printf(m, "# latency: %lu us, #%lu/%lu, CPU#%d |"
+		   " (M:%s VP:%d, KP:%d, SP:%d HP:%d",
+		   nsecs_to_usecs(data->saved_latency),
+		   entries,
+		   total,
+		   buf->cpu,
+#if defined(CONFIG_PREEMPT_NONE)
+		   "server",
+#elif defined(CONFIG_PREEMPT_VOLUNTARY)
+		   "desktop",
+#elif defined(CONFIG_PREEMPT)
+		   "preempt",
+#else
+		   "unknown",
+#endif
+		   /* These are reserved for later use */
+		   0, 0, 0, 0);
+#ifdef CONFIG_SMP
+	seq_printf(m, " #P:%d)\n", num_online_cpus());
+#else
+	seq_puts(m, ")\n");
+#endif
+	seq_puts(m, "#    -----------------\n");
+	seq_printf(m, "#    | task: %.16s-%d "
+		   "(uid:%d nice:%ld policy:%ld rt_prio:%ld)\n",
+		   data->comm, data->pid,
+		   from_kuid_munged(seq_user_ns(m), data->uid), data->nice,
+		   data->policy, data->rt_priority);
+	seq_puts(m, "#    -----------------\n");
+
+	if (data->critical_start) {
+		seq_puts(m, "#  => started at: ");
+		seq_print_ip_sym(&iter->seq, data->critical_start, sym_flags);
+		trace_print_seq(m, &iter->seq);
+		seq_puts(m, "\n#  => ended at:   ");
+		seq_print_ip_sym(&iter->seq, data->critical_end, sym_flags);
+		trace_print_seq(m, &iter->seq);
+		seq_puts(m, "\n#\n");
+	}
+
+	seq_puts(m, "#\n");
+}
+
+static void test_cpu_buff_start(struct trace_iterator *iter)
+{
+	struct trace_seq *s = &iter->seq;
+	struct trace_array *tr = iter->tr;
+
+	if (!(tr->trace_flags & TRACE_ITER_ANNOTATE))
+		return;
+
+	if (!(iter->iter_flags & TRACE_FILE_ANNOTATE))
+		return;
+
+	if (cpumask_available(iter->started) &&
+	    cpumask_test_cpu(iter->cpu, iter->started))
+		return;
+
+	if (per_cpu_ptr(iter->trace_buffer->data, iter->cpu)->skipped_entries)
+		return;
+
+	if (cpumask_available(iter->started))
+		cpumask_set_cpu(iter->cpu, iter->started);
+
+	/* Don't print started cpu buffer for the first entry of the trace */
+	if (iter->idx > 1)
+		trace_seq_printf(s, "##### CPU %u buffer started ####\n",
+				iter->cpu);
+}
+
+static enum print_line_t print_trace_fmt(struct trace_iterator *iter)
+{
+	struct trace_array *tr = iter->tr;
+	struct trace_seq *s = &iter->seq;
+	unsigned long sym_flags = (tr->trace_flags & TRACE_ITER_SYM_MASK);
+	struct trace_entry *entry;
+	struct trace_event *event;
+
+	entry = iter->ent;
+
+	test_cpu_buff_start(iter);
+
+	event = ftrace_find_event(entry->type);
+
+	if (tr->trace_flags & TRACE_ITER_CONTEXT_INFO) {
+		if (iter->iter_flags & TRACE_FILE_LAT_FMT)
+			trace_print_lat_context(iter);
+		else
+			trace_print_context(iter);
+	}
+
+	if (trace_seq_has_overflowed(s))
+		return TRACE_TYPE_PARTIAL_LINE;
+
+	if (event)
+		return event->funcs->trace(iter, sym_flags, event);
+
+	trace_seq_printf(s, "Unknown type %d\n", entry->type);
+
+	return trace_handle_return(s);
+}
+
+static enum print_line_t print_raw_fmt(struct trace_iterator *iter)
+{
+	struct trace_array *tr = iter->tr;
+	struct trace_seq *s = &iter->seq;
+	struct trace_entry *entry;
+	struct trace_event *event;
+
+	entry = iter->ent;
+
+	if (tr->trace_flags & TRACE_ITER_CONTEXT_INFO)
+		trace_seq_printf(s, "%d %d %llu ",
+				 entry->pid, iter->cpu, iter->ts);
+
+	if (trace_seq_has_overflowed(s))
+		return TRACE_TYPE_PARTIAL_LINE;
+
+	event = ftrace_find_event(entry->type);
+	if (event)
+		return event->funcs->raw(iter, 0, event);
+
+	trace_seq_printf(s, "%d ?\n", entry->type);
+
+	return trace_handle_return(s);
+}
+
+static enum print_line_t print_hex_fmt(struct trace_iterator *iter)
+{
+	struct trace_array *tr = iter->tr;
+	struct trace_seq *s = &iter->seq;
+	unsigned char newline = '\n';
+	struct trace_entry *entry;
+	struct trace_event *event;
+
+	entry = iter->ent;
+
+	if (tr->trace_flags & TRACE_ITER_CONTEXT_INFO) {
+		SEQ_PUT_HEX_FIELD(s, entry->pid);
+		SEQ_PUT_HEX_FIELD(s, iter->cpu);
+		SEQ_PUT_HEX_FIELD(s, iter->ts);
+		if (trace_seq_has_overflowed(s))
+			return TRACE_TYPE_PARTIAL_LINE;
+	}
+
+	event = ftrace_find_event(entry->type);
+	if (event) {
+		enum print_line_t ret = event->funcs->hex(iter, 0, event);
+		if (ret != TRACE_TYPE_HANDLED)
+			return ret;
+	}
+
+	SEQ_PUT_FIELD(s, newline);
+
+	return trace_handle_return(s);
+}
+
+static enum print_line_t print_bin_fmt(struct trace_iterator *iter)
+{
+	struct trace_array *tr = iter->tr;
+	struct trace_seq *s = &iter->seq;
+	struct trace_entry *entry;
+	struct trace_event *event;
+
+	entry = iter->ent;
+
+	if (tr->trace_flags & TRACE_ITER_CONTEXT_INFO) {
+		SEQ_PUT_FIELD(s, entry->pid);
+		SEQ_PUT_FIELD(s, iter->cpu);
+		SEQ_PUT_FIELD(s, iter->ts);
+		if (trace_seq_has_overflowed(s))
+			return TRACE_TYPE_PARTIAL_LINE;
+	}
+
+	event = ftrace_find_event(entry->type);
+	return event ? event->funcs->binary(iter, 0, event) :
+		TRACE_TYPE_HANDLED;
+}
+
+int trace_empty(struct trace_iterator *iter)
+{
+	struct ring_buffer_iter *buf_iter;
+	int cpu;
+
+	/* If we are looking at one CPU buffer, only check that one */
+	if (iter->cpu_file != RING_BUFFER_ALL_CPUS) {
+		cpu = iter->cpu_file;
+		buf_iter = trace_buffer_iter(iter, cpu);
+		if (buf_iter) {
+			if (!ring_buffer_iter_empty(buf_iter))
+				return 0;
+		} else {
+			if (!ring_buffer_empty_cpu(iter->trace_buffer->buffer, cpu))
+				return 0;
+		}
+		return 1;
+	}
+
+	for_each_tracing_cpu(cpu) {
+		buf_iter = trace_buffer_iter(iter, cpu);
+		if (buf_iter) {
+			if (!ring_buffer_iter_empty(buf_iter))
+				return 0;
+		} else {
+			if (!ring_buffer_empty_cpu(iter->trace_buffer->buffer, cpu))
+				return 0;
+		}
+	}
+
+	return 1;
+}
+
+/*  Called with trace_event_read_lock() held. */
+enum print_line_t print_trace_line(struct trace_iterator *iter)
+{
+	struct trace_array *tr = iter->tr;
+	unsigned long trace_flags = tr->trace_flags;
+	enum print_line_t ret;
+
+	if (iter->lost_events) {
+		trace_seq_printf(&iter->seq, "CPU:%d [LOST %lu EVENTS]\n",
+				 iter->cpu, iter->lost_events);
+		if (trace_seq_has_overflowed(&iter->seq))
+			return TRACE_TYPE_PARTIAL_LINE;
+	}
+
+	if (iter->trace && iter->trace->print_line) {
+		ret = iter->trace->print_line(iter);
+		if (ret != TRACE_TYPE_UNHANDLED)
+			return ret;
+	}
+
+	if (iter->ent->type == TRACE_BPUTS &&
+			trace_flags & TRACE_ITER_PRINTK &&
+			trace_flags & TRACE_ITER_PRINTK_MSGONLY)
+		return trace_print_bputs_msg_only(iter);
+
+	if (iter->ent->type == TRACE_BPRINT &&
+			trace_flags & TRACE_ITER_PRINTK &&
+			trace_flags & TRACE_ITER_PRINTK_MSGONLY)
+		return trace_print_bprintk_msg_only(iter);
+
+	if (iter->ent->type == TRACE_PRINT &&
+			trace_flags & TRACE_ITER_PRINTK &&
+			trace_flags & TRACE_ITER_PRINTK_MSGONLY)
+		return trace_print_printk_msg_only(iter);
+
+	if (trace_flags & TRACE_ITER_BIN)
+		return print_bin_fmt(iter);
+
+	if (trace_flags & TRACE_ITER_HEX)
+		return print_hex_fmt(iter);
+
+	if (trace_flags & TRACE_ITER_RAW)
+		return print_raw_fmt(iter);
+
+	return print_trace_fmt(iter);
+}
+
+void trace_latency_header(struct seq_file *m)
+{
+	struct trace_iterator *iter = m->private;
+	struct trace_array *tr = iter->tr;
+
+	/* print nothing if the buffers are empty */
+	if (trace_empty(iter))
+		return;
+
+	if (iter->iter_flags & TRACE_FILE_LAT_FMT)
+		print_trace_header(m, iter);
+
+	if (!(tr->trace_flags & TRACE_ITER_VERBOSE))
+		print_lat_help_header(m);
+}
+
+void trace_default_header(struct seq_file *m)
+{
+	struct trace_iterator *iter = m->private;
+	struct trace_array *tr = iter->tr;
+	unsigned long trace_flags = tr->trace_flags;
+
+	if (!(trace_flags & TRACE_ITER_CONTEXT_INFO))
+		return;
+
+	if (iter->iter_flags & TRACE_FILE_LAT_FMT) {
+		/* print nothing if the buffers are empty */
+		if (trace_empty(iter))
+			return;
+		print_trace_header(m, iter);
+		if (!(trace_flags & TRACE_ITER_VERBOSE))
+			print_lat_help_header(m);
+	} else {
+		if (!(trace_flags & TRACE_ITER_VERBOSE)) {
+			if (trace_flags & TRACE_ITER_IRQ_INFO)
+				print_func_help_header_irq(iter->trace_buffer,
+							   m, trace_flags);
+			else
+				print_func_help_header(iter->trace_buffer, m,
+						       trace_flags);
+		}
+	}
+}
+
+static void test_ftrace_alive(struct seq_file *m)
+{
+	if (!ftrace_is_dead())
+		return;
+	seq_puts(m, "# WARNING: FUNCTION TRACING IS CORRUPTED\n"
+		    "#          MAY BE MISSING FUNCTION EVENTS\n");
+}
+
+#ifdef CONFIG_TRACER_MAX_TRACE
+static void show_snapshot_main_help(struct seq_file *m)
+{
+	seq_puts(m, "# echo 0 > snapshot : Clears and frees snapshot buffer\n"
+		    "# echo 1 > snapshot : Allocates snapshot buffer, if not already allocated.\n"
+		    "#                      Takes a snapshot of the main buffer.\n"
+		    "# echo 2 > snapshot : Clears snapshot buffer (but does not allocate or free)\n"
+		    "#                      (Doesn't have to be '2' works with any number that\n"
+		    "#                       is not a '0' or '1')\n");
+}
+
+static void show_snapshot_percpu_help(struct seq_file *m)
+{
+	seq_puts(m, "# echo 0 > snapshot : Invalid for per_cpu snapshot file.\n");
+#ifdef CONFIG_RING_BUFFER_ALLOW_SWAP
+	seq_puts(m, "# echo 1 > snapshot : Allocates snapshot buffer, if not already allocated.\n"
+		    "#                      Takes a snapshot of the main buffer for this cpu.\n");
+#else
+	seq_puts(m, "# echo 1 > snapshot : Not supported with this kernel.\n"
+		    "#                     Must use main snapshot file to allocate.\n");
+#endif
+	seq_puts(m, "# echo 2 > snapshot : Clears this cpu's snapshot buffer (but does not allocate)\n"
+		    "#                      (Doesn't have to be '2' works with any number that\n"
+		    "#                       is not a '0' or '1')\n");
+}
+
+static void print_snapshot_help(struct seq_file *m, struct trace_iterator *iter)
+{
+	if (iter->tr->allocated_snapshot)
+		seq_puts(m, "#\n# * Snapshot is allocated *\n#\n");
+	else
+		seq_puts(m, "#\n# * Snapshot is freed *\n#\n");
+
+	seq_puts(m, "# Snapshot commands:\n");
+	if (iter->cpu_file == RING_BUFFER_ALL_CPUS)
+		show_snapshot_main_help(m);
+	else
+		show_snapshot_percpu_help(m);
+}
+#else
+/* Should never be called */
+static inline void print_snapshot_help(struct seq_file *m, struct trace_iterator *iter) { }
+#endif
+
+static int s_show(struct seq_file *m, void *v)
+{
+	struct trace_iterator *iter = v;
+	int ret;
+
+	if (iter->ent == NULL) {
+		if (iter->tr) {
+			seq_printf(m, "# tracer: %s\n", iter->trace->name);
+			seq_puts(m, "#\n");
+			test_ftrace_alive(m);
+		}
+		if (iter->snapshot && trace_empty(iter))
+			print_snapshot_help(m, iter);
+		else if (iter->trace && iter->trace->print_header)
+			iter->trace->print_header(m);
+		else
+			trace_default_header(m);
+
+	} else if (iter->leftover) {
+		/*
+		 * If we filled the seq_file buffer earlier, we
+		 * want to just show it now.
+		 */
+		ret = trace_print_seq(m, &iter->seq);
+
+		/* ret should this time be zero, but you never know */
+		iter->leftover = ret;
+
+	} else {
+		print_trace_line(iter);
+		ret = trace_print_seq(m, &iter->seq);
+		/*
+		 * If we overflow the seq_file buffer, then it will
+		 * ask us for this data again at start up.
+		 * Use that instead.
+		 *  ret is 0 if seq_file write succeeded.
+		 *        -1 otherwise.
+		 */
+		iter->leftover = ret;
+	}
+
+	return 0;
+}
+
+/*
+ * Should be used after trace_array_get(), trace_types_lock
+ * ensures that i_cdev was already initialized.
+ */
+static inline int tracing_get_cpu(struct inode *inode)
+{
+	if (inode->i_cdev) /* See trace_create_cpu_file() */
+		return (long)inode->i_cdev - 1;
+	return RING_BUFFER_ALL_CPUS;
+}
+
+static const struct seq_operations tracer_seq_ops = {
+	.start		= s_start,
+	.next		= s_next,
+	.stop		= s_stop,
+	.show		= s_show,
+};
+
+static struct trace_iterator *
+__tracing_open(struct inode *inode, struct file *file, bool snapshot)
+{
+	struct trace_array *tr = inode->i_private;
+	struct trace_iterator *iter;
+	int cpu;
+
+	if (tracing_disabled)
+		return ERR_PTR(-ENODEV);
+
+	iter = __seq_open_private(file, &tracer_seq_ops, sizeof(*iter));
+	if (!iter)
+		return ERR_PTR(-ENOMEM);
+
+	iter->buffer_iter = kcalloc(nr_cpu_ids, sizeof(*iter->buffer_iter),
+				    GFP_KERNEL);
+	if (!iter->buffer_iter)
+		goto release;
+
+	/*
+	 * We make a copy of the current tracer to avoid concurrent
+	 * changes on it while we are reading.
+	 */
+	mutex_lock(&trace_types_lock);
+	iter->trace = kzalloc(sizeof(*iter->trace), GFP_KERNEL);
+	if (!iter->trace)
+		goto fail;
+
+	*iter->trace = *tr->current_trace;
+
+	if (!zalloc_cpumask_var(&iter->started, GFP_KERNEL))
+		goto fail;
+
+	iter->tr = tr;
+
+#ifdef CONFIG_TRACER_MAX_TRACE
+	/* Currently only the top directory has a snapshot */
+	if (tr->current_trace->print_max || snapshot)
+		iter->trace_buffer = &tr->max_buffer;
+	else
+#endif
+		iter->trace_buffer = &tr->trace_buffer;
+	iter->snapshot = snapshot;
+	iter->pos = -1;
+	iter->cpu_file = tracing_get_cpu(inode);
+	mutex_init(&iter->mutex);
+
+	/* Notify the tracer early; before we stop tracing. */
+	if (iter->trace && iter->trace->open)
+		iter->trace->open(iter);
+
+	/* Annotate start of buffers if we had overruns */
+	if (ring_buffer_overruns(iter->trace_buffer->buffer))
+		iter->iter_flags |= TRACE_FILE_ANNOTATE;
+
+	/* Output in nanoseconds only if we are using a clock in nanoseconds. */
+	if (trace_clocks[tr->clock_id].in_ns)
+		iter->iter_flags |= TRACE_FILE_TIME_IN_NS;
+
+	/* stop the trace while dumping if we are not opening "snapshot" */
+	if (!iter->snapshot)
+		tracing_stop_tr(tr);
+
+	if (iter->cpu_file == RING_BUFFER_ALL_CPUS) {
+		for_each_tracing_cpu(cpu) {
+			iter->buffer_iter[cpu] =
+				ring_buffer_read_prepare(iter->trace_buffer->buffer,
+							 cpu, GFP_KERNEL);
+		}
+		ring_buffer_read_prepare_sync();
+		for_each_tracing_cpu(cpu) {
+			ring_buffer_read_start(iter->buffer_iter[cpu]);
+			tracing_iter_reset(iter, cpu);
+		}
+	} else {
+		cpu = iter->cpu_file;
+		iter->buffer_iter[cpu] =
+			ring_buffer_read_prepare(iter->trace_buffer->buffer,
+						 cpu, GFP_KERNEL);
+		ring_buffer_read_prepare_sync();
+		ring_buffer_read_start(iter->buffer_iter[cpu]);
+		tracing_iter_reset(iter, cpu);
+	}
+
+	mutex_unlock(&trace_types_lock);
+
+	return iter;
+
+ fail:
+	mutex_unlock(&trace_types_lock);
+	kfree(iter->trace);
+	kfree(iter->buffer_iter);
+release:
+	seq_release_private(inode, file);
+	return ERR_PTR(-ENOMEM);
+}
+
+int tracing_open_generic(struct inode *inode, struct file *filp)
+{
+	if (tracing_disabled)
+		return -ENODEV;
+
+	filp->private_data = inode->i_private;
+	return 0;
+}
+
+bool tracing_is_disabled(void)
+{
+	return (tracing_disabled) ? true: false;
+}
+
+/*
+ * Open and update trace_array ref count.
+ * Must have the current trace_array passed to it.
+ */
+static int tracing_open_generic_tr(struct inode *inode, struct file *filp)
+{
+	struct trace_array *tr = inode->i_private;
+
+	if (tracing_disabled)
+		return -ENODEV;
+
+	if (trace_array_get(tr) < 0)
+		return -ENODEV;
+
+	filp->private_data = inode->i_private;
+
+	return 0;
+}
+
+static int tracing_release(struct inode *inode, struct file *file)
+{
+	struct trace_array *tr = inode->i_private;
+	struct seq_file *m = file->private_data;
+	struct trace_iterator *iter;
+	int cpu;
+
+	if (!(file->f_mode & FMODE_READ)) {
+		trace_array_put(tr);
+		return 0;
+	}
+
+	/* Writes do not use seq_file */
+	iter = m->private;
+	mutex_lock(&trace_types_lock);
+
+	for_each_tracing_cpu(cpu) {
+		if (iter->buffer_iter[cpu])
+			ring_buffer_read_finish(iter->buffer_iter[cpu]);
+	}
+
+	if (iter->trace && iter->trace->close)
+		iter->trace->close(iter);
+
+	if (!iter->snapshot)
+		/* reenable tracing if it was previously enabled */
+		tracing_start_tr(tr);
+
+	__trace_array_put(tr);
+
+	mutex_unlock(&trace_types_lock);
+
+	mutex_destroy(&iter->mutex);
+	free_cpumask_var(iter->started);
+	kfree(iter->trace);
+	kfree(iter->buffer_iter);
+	seq_release_private(inode, file);
+
+	return 0;
+}
+
+static int tracing_release_generic_tr(struct inode *inode, struct file *file)
+{
+	struct trace_array *tr = inode->i_private;
+
+	trace_array_put(tr);
+	return 0;
+}
+
+static int tracing_single_release_tr(struct inode *inode, struct file *file)
+{
+	struct trace_array *tr = inode->i_private;
+
+	trace_array_put(tr);
+
+	return single_release(inode, file);
+}
+
+static int tracing_open(struct inode *inode, struct file *file)
+{
+	struct trace_array *tr = inode->i_private;
+	struct trace_iterator *iter;
+	int ret = 0;
+
+	if (trace_array_get(tr) < 0)
+		return -ENODEV;
+
+	/* If this file was open for write, then erase contents */
+	if ((file->f_mode & FMODE_WRITE) && (file->f_flags & O_TRUNC)) {
+		int cpu = tracing_get_cpu(inode);
+		struct trace_buffer *trace_buf = &tr->trace_buffer;
+
+#ifdef CONFIG_TRACER_MAX_TRACE
+		if (tr->current_trace->print_max)
+			trace_buf = &tr->max_buffer;
+#endif
+
+		if (cpu == RING_BUFFER_ALL_CPUS)
+			tracing_reset_online_cpus(trace_buf);
+		else
+			tracing_reset(trace_buf, cpu);
+	}
+
+	if (file->f_mode & FMODE_READ) {
+		iter = __tracing_open(inode, file, false);
+		if (IS_ERR(iter))
+			ret = PTR_ERR(iter);
+		else if (tr->trace_flags & TRACE_ITER_LATENCY_FMT)
+			iter->iter_flags |= TRACE_FILE_LAT_FMT;
+	}
+
+	if (ret < 0)
+		trace_array_put(tr);
+
+	return ret;
+}
+
+/*
+ * Some tracers are not suitable for instance buffers.
+ * A tracer is always available for the global array (toplevel)
+ * or if it explicitly states that it is.
+ */
+static bool
+trace_ok_for_array(struct tracer *t, struct trace_array *tr)
+{
+	return (tr->flags & TRACE_ARRAY_FL_GLOBAL) || t->allow_instances;
+}
+
+/* Find the next tracer that this trace array may use */
+static struct tracer *
+get_tracer_for_array(struct trace_array *tr, struct tracer *t)
+{
+	while (t && !trace_ok_for_array(t, tr))
+		t = t->next;
+
+	return t;
+}
+
+static void *
+t_next(struct seq_file *m, void *v, loff_t *pos)
+{
+	struct trace_array *tr = m->private;
+	struct tracer *t = v;
+
+	(*pos)++;
+
+	if (t)
+		t = get_tracer_for_array(tr, t->next);
+
+	return t;
+}
+
+static void *t_start(struct seq_file *m, loff_t *pos)
+{
+	struct trace_array *tr = m->private;
+	struct tracer *t;
+	loff_t l = 0;
+
+	mutex_lock(&trace_types_lock);
+
+	t = get_tracer_for_array(tr, trace_types);
+	for (; t && l < *pos; t = t_next(m, t, &l))
+			;
+
+	return t;
+}
+
+static void t_stop(struct seq_file *m, void *p)
+{
+	mutex_unlock(&trace_types_lock);
+}
+
+static int t_show(struct seq_file *m, void *v)
+{
+	struct tracer *t = v;
+
+	if (!t)
+		return 0;
+
+	seq_puts(m, t->name);
+	if (t->next)
+		seq_putc(m, ' ');
+	else
+		seq_putc(m, '\n');
+
+	return 0;
+}
+
+static const struct seq_operations show_traces_seq_ops = {
+	.start		= t_start,
+	.next		= t_next,
+	.stop		= t_stop,
+	.show		= t_show,
+};
+
+static int show_traces_open(struct inode *inode, struct file *file)
+{
+	struct trace_array *tr = inode->i_private;
+	struct seq_file *m;
+	int ret;
+
+	if (tracing_disabled)
+		return -ENODEV;
+
+	if (trace_array_get(tr) < 0)
+		return -ENODEV;
+
+	ret = seq_open(file, &show_traces_seq_ops);
+	if (ret) {
+		trace_array_put(tr);
+		return ret;
+	}
+
+	m = file->private_data;
+	m->private = tr;
+
+	return 0;
+}
+
+static int show_traces_release(struct inode *inode, struct file *file)
+{
+	struct trace_array *tr = inode->i_private;
+
+	trace_array_put(tr);
+	return seq_release(inode, file);
+}
+
+static ssize_t
+tracing_write_stub(struct file *filp, const char __user *ubuf,
+		   size_t count, loff_t *ppos)
+{
+	return count;
+}
+
+loff_t tracing_lseek(struct file *file, loff_t offset, int whence)
+{
+	int ret;
+
+	if (file->f_mode & FMODE_READ)
+		ret = seq_lseek(file, offset, whence);
+	else
+		file->f_pos = ret = 0;
+
+	return ret;
+}
+
+static const struct file_operations tracing_fops = {
+	.open		= tracing_open,
+	.read		= seq_read,
+	.write		= tracing_write_stub,
+	.llseek		= tracing_lseek,
+	.release	= tracing_release,
+};
+
+static const struct file_operations show_traces_fops = {
+	.open		= show_traces_open,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.release	= show_traces_release,
+};
+
+static ssize_t
+tracing_cpumask_read(struct file *filp, char __user *ubuf,
+		     size_t count, loff_t *ppos)
+{
+	struct trace_array *tr = file_inode(filp)->i_private;
+	char *mask_str;
+	int len;
+
+	len = snprintf(NULL, 0, "%*pb\n",
+		       cpumask_pr_args(tr->tracing_cpumask)) + 1;
+	mask_str = kmalloc(len, GFP_KERNEL);
+	if (!mask_str)
+		return -ENOMEM;
+
+	len = snprintf(mask_str, len, "%*pb\n",
+		       cpumask_pr_args(tr->tracing_cpumask));
+	if (len >= count) {
+		count = -EINVAL;
+		goto out_err;
+	}
+	count = simple_read_from_buffer(ubuf, count, ppos, mask_str, len);
+
+out_err:
+	kfree(mask_str);
+
+	return count;
+}
+
+static ssize_t
+tracing_cpumask_write(struct file *filp, const char __user *ubuf,
+		      size_t count, loff_t *ppos)
+{
+	struct trace_array *tr = file_inode(filp)->i_private;
+	cpumask_var_t tracing_cpumask_new;
+	int err, cpu;
+
+	if (!alloc_cpumask_var(&tracing_cpumask_new, GFP_KERNEL))
+		return -ENOMEM;
+
+	err = cpumask_parse_user(ubuf, count, tracing_cpumask_new);
+	if (err)
+		goto err_unlock;
+
+	local_irq_disable();
+	arch_spin_lock(&tr->max_lock);
+	for_each_tracing_cpu(cpu) {
+		/*
+		 * Increase/decrease the disabled counter if we are
+		 * about to flip a bit in the cpumask:
+		 */
+		if (cpumask_test_cpu(cpu, tr->tracing_cpumask) &&
+				!cpumask_test_cpu(cpu, tracing_cpumask_new)) {
+			atomic_inc(&per_cpu_ptr(tr->trace_buffer.data, cpu)->disabled);
+			ring_buffer_record_disable_cpu(tr->trace_buffer.buffer, cpu);
+		}
+		if (!cpumask_test_cpu(cpu, tr->tracing_cpumask) &&
+				cpumask_test_cpu(cpu, tracing_cpumask_new)) {
+			atomic_dec(&per_cpu_ptr(tr->trace_buffer.data, cpu)->disabled);
+			ring_buffer_record_enable_cpu(tr->trace_buffer.buffer, cpu);
+		}
+	}
+	arch_spin_unlock(&tr->max_lock);
+	local_irq_enable();
+
+	cpumask_copy(tr->tracing_cpumask, tracing_cpumask_new);
+	free_cpumask_var(tracing_cpumask_new);
+
+	return count;
+
+err_unlock:
+	free_cpumask_var(tracing_cpumask_new);
+
+	return err;
+}
+
+static const struct file_operations tracing_cpumask_fops = {
+	.open		= tracing_open_generic_tr,
+	.read		= tracing_cpumask_read,
+	.write		= tracing_cpumask_write,
+	.release	= tracing_release_generic_tr,
+	.llseek		= generic_file_llseek,
+};
+
+static int tracing_trace_options_show(struct seq_file *m, void *v)
+{
+	struct tracer_opt *trace_opts;
+	struct trace_array *tr = m->private;
+	u32 tracer_flags;
+	int i;
+
+	mutex_lock(&trace_types_lock);
+	tracer_flags = tr->current_trace->flags->val;
+	trace_opts = tr->current_trace->flags->opts;
+
+	for (i = 0; trace_options[i]; i++) {
+		if (tr->trace_flags & (1 << i))
+			seq_printf(m, "%s\n", trace_options[i]);
+		else
+			seq_printf(m, "no%s\n", trace_options[i]);
+	}
+
+	for (i = 0; trace_opts[i].name; i++) {
+		if (tracer_flags & trace_opts[i].bit)
+			seq_printf(m, "%s\n", trace_opts[i].name);
+		else
+			seq_printf(m, "no%s\n", trace_opts[i].name);
+	}
+	mutex_unlock(&trace_types_lock);
+
+	return 0;
+}
+
+static int __set_tracer_option(struct trace_array *tr,
+			       struct tracer_flags *tracer_flags,
+			       struct tracer_opt *opts, int neg)
+{
+	struct tracer *trace = tracer_flags->trace;
+	int ret;
+
+	ret = trace->set_flag(tr, tracer_flags->val, opts->bit, !neg);
+	if (ret)
+		return ret;
+
+	if (neg)
+		tracer_flags->val &= ~opts->bit;
+	else
+		tracer_flags->val |= opts->bit;
+	return 0;
+}
+
+/* Try to assign a tracer specific option */
+static int set_tracer_option(struct trace_array *tr, char *cmp, int neg)
+{
+	struct tracer *trace = tr->current_trace;
+	struct tracer_flags *tracer_flags = trace->flags;
+	struct tracer_opt *opts = NULL;
+	int i;
+
+	for (i = 0; tracer_flags->opts[i].name; i++) {
+		opts = &tracer_flags->opts[i];
+
+		if (strcmp(cmp, opts->name) == 0)
+			return __set_tracer_option(tr, trace->flags, opts, neg);
+	}
+
+	return -EINVAL;
+}
+
+/* Some tracers require overwrite to stay enabled */
+int trace_keep_overwrite(struct tracer *tracer, u32 mask, int set)
+{
+	if (tracer->enabled && (mask & TRACE_ITER_OVERWRITE) && !set)
+		return -1;
+
+	return 0;
+}
+
+int set_tracer_flag(struct trace_array *tr, unsigned int mask, int enabled)
+{
+	int *map;
+
+	if ((mask == TRACE_ITER_RECORD_TGID) ||
+	    (mask == TRACE_ITER_RECORD_CMD))
+		lockdep_assert_held(&event_mutex);
+
+	/* do nothing if flag is already set */
+	if (!!(tr->trace_flags & mask) == !!enabled)
+		return 0;
+
+	/* Give the tracer a chance to approve the change */
+	if (tr->current_trace->flag_changed)
+		if (tr->current_trace->flag_changed(tr, mask, !!enabled))
+			return -EINVAL;
+
+	if (enabled)
+		tr->trace_flags |= mask;
+	else
+		tr->trace_flags &= ~mask;
+
+	if (mask == TRACE_ITER_RECORD_CMD)
+		trace_event_enable_cmd_record(enabled);
+
+	if (mask == TRACE_ITER_RECORD_TGID) {
+		if (!tgid_map) {
+			tgid_map_max = pid_max;
+			map = kvcalloc(tgid_map_max + 1, sizeof(*tgid_map),
+				       GFP_KERNEL);
+
+			/*
+			 * Pairs with smp_load_acquire() in
+			 * trace_find_tgid_ptr() to ensure that if it observes
+			 * the tgid_map we just allocated then it also observes
+			 * the corresponding tgid_map_max value.
+			 */
+			smp_store_release(&tgid_map, map);
+		}
+		if (!tgid_map) {
+			tr->trace_flags &= ~TRACE_ITER_RECORD_TGID;
+			return -ENOMEM;
+		}
+
+		trace_event_enable_tgid_record(enabled);
+	}
+
+	if (mask == TRACE_ITER_EVENT_FORK)
+		trace_event_follow_fork(tr, enabled);
+
+	if (mask == TRACE_ITER_FUNC_FORK)
+		ftrace_pid_follow_fork(tr, enabled);
+
+	if (mask == TRACE_ITER_OVERWRITE) {
+		ring_buffer_change_overwrite(tr->trace_buffer.buffer, enabled);
+#ifdef CONFIG_TRACER_MAX_TRACE
+		ring_buffer_change_overwrite(tr->max_buffer.buffer, enabled);
+#endif
+	}
+
+	if (mask == TRACE_ITER_PRINTK) {
+		trace_printk_start_stop_comm(enabled);
+		trace_printk_control(enabled);
+	}
+
+	return 0;
+}
+
+static int trace_set_options(struct trace_array *tr, char *option)
+{
+	char *cmp;
+	int neg = 0;
+	int ret;
+	size_t orig_len = strlen(option);
+
+	cmp = strstrip(option);
+
+	if (strncmp(cmp, "no", 2) == 0) {
+		neg = 1;
+		cmp += 2;
+	}
+
+	mutex_lock(&event_mutex);
+	mutex_lock(&trace_types_lock);
+
+	ret = match_string(trace_options, -1, cmp);
+	/* If no option could be set, test the specific tracer options */
+	if (ret < 0)
+		ret = set_tracer_option(tr, cmp, neg);
+	else
+		ret = set_tracer_flag(tr, 1 << ret, !neg);
+
+	mutex_unlock(&trace_types_lock);
+	mutex_unlock(&event_mutex);
+
+	/*
+	 * If the first trailing whitespace is replaced with '\0' by strstrip,
+	 * turn it back into a space.
+	 */
+	if (orig_len > strlen(option))
+		option[strlen(option)] = ' ';
+
+	return ret;
+}
+
+static void __init apply_trace_boot_options(void)
+{
+	char *buf = trace_boot_options_buf;
+	char *option;
+
+	while (true) {
+		option = strsep(&buf, ",");
+
+		if (!option)
+			break;
+
+		if (*option)
+			trace_set_options(&global_trace, option);
+
+		/* Put back the comma to allow this to be called again */
+		if (buf)
+			*(buf - 1) = ',';
+	}
+}
+
+static ssize_t
+tracing_trace_options_write(struct file *filp, const char __user *ubuf,
+			size_t cnt, loff_t *ppos)
+{
+	struct seq_file *m = filp->private_data;
+	struct trace_array *tr = m->private;
+	char buf[64];
+	int ret;
+
+	if (cnt >= sizeof(buf))
+		return -EINVAL;
+
+	if (copy_from_user(buf, ubuf, cnt))
+		return -EFAULT;
+
+	buf[cnt] = 0;
+
+	ret = trace_set_options(tr, buf);
+	if (ret < 0)
+		return ret;
+
+	*ppos += cnt;
+
+	return cnt;
+}
+
+static int tracing_trace_options_open(struct inode *inode, struct file *file)
+{
+	struct trace_array *tr = inode->i_private;
+	int ret;
+
+	if (tracing_disabled)
+		return -ENODEV;
+
+	if (trace_array_get(tr) < 0)
+		return -ENODEV;
+
+	ret = single_open(file, tracing_trace_options_show, inode->i_private);
+	if (ret < 0)
+		trace_array_put(tr);
+
+	return ret;
+}
+
+static const struct file_operations tracing_iter_fops = {
+	.open		= tracing_trace_options_open,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.release	= tracing_single_release_tr,
+	.write		= tracing_trace_options_write,
+};
+
+static const char readme_msg[] =
+	"tracing mini-HOWTO:\n\n"
+	"# echo 0 > tracing_on : quick way to disable tracing\n"
+	"# echo 1 > tracing_on : quick way to re-enable tracing\n\n"
+	" Important files:\n"
+	"  trace\t\t\t- The static contents of the buffer\n"
+	"\t\t\t  To clear the buffer write into this file: echo > trace\n"
+	"  trace_pipe\t\t- A consuming read to see the contents of the buffer\n"
+	"  current_tracer\t- function and latency tracers\n"
+	"  available_tracers\t- list of configured tracers for current_tracer\n"
+	"  buffer_size_kb\t- view and modify size of per cpu buffer\n"
+	"  buffer_total_size_kb  - view total size of all cpu buffers\n\n"
+	"  trace_clock\t\t-change the clock used to order events\n"
+	"       local:   Per cpu clock but may not be synced across CPUs\n"
+	"      global:   Synced across CPUs but slows tracing down.\n"
+	"     counter:   Not a clock, but just an increment\n"
+	"      uptime:   Jiffy counter from time of boot\n"
+	"        perf:   Same clock that perf events use\n"
+#ifdef CONFIG_X86_64
+	"     x86-tsc:   TSC cycle counter\n"
+#endif
+	"\n  timestamp_mode\t-view the mode used to timestamp events\n"
+	"       delta:   Delta difference against a buffer-wide timestamp\n"
+	"    absolute:   Absolute (standalone) timestamp\n"
+	"\n  trace_marker\t\t- Writes into this file writes into the kernel buffer\n"
+	"\n  trace_marker_raw\t\t- Writes into this file writes binary data into the kernel buffer\n"
+	"  tracing_cpumask\t- Limit which CPUs to trace\n"
+	"  instances\t\t- Make sub-buffers with: mkdir instances/foo\n"
+	"\t\t\t  Remove sub-buffer with rmdir\n"
+	"  trace_options\t\t- Set format or modify how tracing happens\n"
+	"\t\t\t  Disable an option by adding a suffix 'no' to the\n"
+	"\t\t\t  option name\n"
+	"  saved_cmdlines_size\t- echo command number in here to store comm-pid list\n"
+#ifdef CONFIG_DYNAMIC_FTRACE
+	"\n  available_filter_functions - list of functions that can be filtered on\n"
+	"  set_ftrace_filter\t- echo function name in here to only trace these\n"
+	"\t\t\t  functions\n"
+	"\t     accepts: func_full_name or glob-matching-pattern\n"
+	"\t     modules: Can select a group via module\n"
+	"\t      Format: :mod:<module-name>\n"
+	"\t     example: echo :mod:ext3 > set_ftrace_filter\n"
+	"\t    triggers: a command to perform when function is hit\n"
+	"\t      Format: <function>:<trigger>[:count]\n"
+	"\t     trigger: traceon, traceoff\n"
+	"\t\t      enable_event:<system>:<event>\n"
+	"\t\t      disable_event:<system>:<event>\n"
+#ifdef CONFIG_STACKTRACE
+	"\t\t      stacktrace\n"
+#endif
+#ifdef CONFIG_TRACER_SNAPSHOT
+	"\t\t      snapshot\n"
+#endif
+	"\t\t      dump\n"
+	"\t\t      cpudump\n"
+	"\t     example: echo do_fault:traceoff > set_ftrace_filter\n"
+	"\t              echo do_trap:traceoff:3 > set_ftrace_filter\n"
+	"\t     The first one will disable tracing every time do_fault is hit\n"
+	"\t     The second will disable tracing at most 3 times when do_trap is hit\n"
+	"\t       The first time do trap is hit and it disables tracing, the\n"
+	"\t       counter will decrement to 2. If tracing is already disabled,\n"
+	"\t       the counter will not decrement. It only decrements when the\n"
+	"\t       trigger did work\n"
+	"\t     To remove trigger without count:\n"
+	"\t       echo '!<function>:<trigger> > set_ftrace_filter\n"
+	"\t     To remove trigger with a count:\n"
+	"\t       echo '!<function>:<trigger>:0 > set_ftrace_filter\n"
+	"  set_ftrace_notrace\t- echo function name in here to never trace.\n"
+	"\t    accepts: func_full_name, *func_end, func_begin*, *func_middle*\n"
+	"\t    modules: Can select a group via module command :mod:\n"
+	"\t    Does not accept triggers\n"
+#endif /* CONFIG_DYNAMIC_FTRACE */
+#ifdef CONFIG_FUNCTION_TRACER
+	"  set_ftrace_pid\t- Write pid(s) to only function trace those pids\n"
+	"\t\t    (function)\n"
+#endif
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+	"  set_graph_function\t- Trace the nested calls of a function (function_graph)\n"
+	"  set_graph_notrace\t- Do not trace the nested calls of a function (function_graph)\n"
+	"  max_graph_depth\t- Trace a limited depth of nested calls (0 is unlimited)\n"
+#endif
+#ifdef CONFIG_TRACER_SNAPSHOT
+	"\n  snapshot\t\t- Like 'trace' but shows the content of the static\n"
+	"\t\t\t  snapshot buffer. Read the contents for more\n"
+	"\t\t\t  information\n"
+#endif
+#ifdef CONFIG_STACK_TRACER
+	"  stack_trace\t\t- Shows the max stack trace when active\n"
+	"  stack_max_size\t- Shows current max stack size that was traced\n"
+	"\t\t\t  Write into this file to reset the max size (trigger a\n"
+	"\t\t\t  new trace)\n"
+#ifdef CONFIG_DYNAMIC_FTRACE
+	"  stack_trace_filter\t- Like set_ftrace_filter but limits what stack_trace\n"
+	"\t\t\t  traces\n"
+#endif
+#endif /* CONFIG_STACK_TRACER */
+#ifdef CONFIG_KPROBE_EVENTS
+	"  kprobe_events\t\t- Add/remove/show the kernel dynamic events\n"
+	"\t\t\t  Write into this file to define/undefine new trace events.\n"
+#endif
+#ifdef CONFIG_UPROBE_EVENTS
+	"  uprobe_events\t\t- Add/remove/show the userspace dynamic events\n"
+	"\t\t\t  Write into this file to define/undefine new trace events.\n"
+#endif
+#if defined(CONFIG_KPROBE_EVENTS) || defined(CONFIG_UPROBE_EVENTS)
+	"\t  accepts: event-definitions (one definition per line)\n"
+	"\t   Format: p[:[<group>/]<event>] <place> [<args>]\n"
+	"\t           r[maxactive][:[<group>/]<event>] <place> [<args>]\n"
+	"\t           -:[<group>/]<event>\n"
+#ifdef CONFIG_KPROBE_EVENTS
+	"\t    place: [<module>:]<symbol>[+<offset>]|<memaddr>\n"
+  "place (kretprobe): [<module>:]<symbol>[+<offset>]|<memaddr>\n"
+#endif
+#ifdef CONFIG_UPROBE_EVENTS
+	"\t    place: <path>:<offset>\n"
+#endif
+	"\t     args: <name>=fetcharg[:type]\n"
+	"\t fetcharg: %<register>, @<address>, @<symbol>[+|-<offset>],\n"
+	"\t           $stack<index>, $stack, $retval, $comm\n"
+	"\t     type: s8/16/32/64, u8/16/32/64, x8/16/32/64, string,\n"
+	"\t           b<bit-width>@<bit-offset>/<container-size>\n"
+#endif
+	"  events/\t\t- Directory containing all trace event subsystems:\n"
+	"      enable\t\t- Write 0/1 to enable/disable tracing of all events\n"
+	"  events/<system>/\t- Directory containing all trace events for <system>:\n"
+	"      enable\t\t- Write 0/1 to enable/disable tracing of all <system>\n"
+	"\t\t\t  events\n"
+	"      filter\t\t- If set, only events passing filter are traced\n"
+	"  events/<system>/<event>/\t- Directory containing control files for\n"
+	"\t\t\t  <event>:\n"
+	"      enable\t\t- Write 0/1 to enable/disable tracing of <event>\n"
+	"      filter\t\t- If set, only events passing filter are traced\n"
+	"      trigger\t\t- If set, a command to perform when event is hit\n"
+	"\t    Format: <trigger>[:count][if <filter>]\n"
+	"\t   trigger: traceon, traceoff\n"
+	"\t            enable_event:<system>:<event>\n"
+	"\t            disable_event:<system>:<event>\n"
+#ifdef CONFIG_HIST_TRIGGERS
+	"\t            enable_hist:<system>:<event>\n"
+	"\t            disable_hist:<system>:<event>\n"
+#endif
+#ifdef CONFIG_STACKTRACE
+	"\t\t    stacktrace\n"
+#endif
+#ifdef CONFIG_TRACER_SNAPSHOT
+	"\t\t    snapshot\n"
+#endif
+#ifdef CONFIG_HIST_TRIGGERS
+	"\t\t    hist (see below)\n"
+#endif
+	"\t   example: echo traceoff > events/block/block_unplug/trigger\n"
+	"\t            echo traceoff:3 > events/block/block_unplug/trigger\n"
+	"\t            echo 'enable_event:kmem:kmalloc:3 if nr_rq > 1' > \\\n"
+	"\t                  events/block/block_unplug/trigger\n"
+	"\t   The first disables tracing every time block_unplug is hit.\n"
+	"\t   The second disables tracing the first 3 times block_unplug is hit.\n"
+	"\t   The third enables the kmalloc event the first 3 times block_unplug\n"
+	"\t     is hit and has value of greater than 1 for the 'nr_rq' event field.\n"
+	"\t   Like function triggers, the counter is only decremented if it\n"
+	"\t    enabled or disabled tracing.\n"
+	"\t   To remove a trigger without a count:\n"
+	"\t     echo '!<trigger> > <system>/<event>/trigger\n"
+	"\t   To remove a trigger with a count:\n"
+	"\t     echo '!<trigger>:0 > <system>/<event>/trigger\n"
+	"\t   Filters can be ignored when removing a trigger.\n"
+#ifdef CONFIG_HIST_TRIGGERS
+	"      hist trigger\t- If set, event hits are aggregated into a hash table\n"
+	"\t    Format: hist:keys=<field1[,field2,...]>\n"
+	"\t            [:values=<field1[,field2,...]>]\n"
+	"\t            [:sort=<field1[,field2,...]>]\n"
+	"\t            [:size=#entries]\n"
+	"\t            [:pause][:continue][:clear]\n"
+	"\t            [:name=histname1]\n"
+	"\t            [if <filter>]\n\n"
+	"\t    Note, special fields can be used as well:\n"
+	"\t            common_timestamp - to record current timestamp\n"
+	"\t            common_cpu - to record the CPU the event happened on\n"
+	"\n"
+	"\t    When a matching event is hit, an entry is added to a hash\n"
+	"\t    table using the key(s) and value(s) named, and the value of a\n"
+	"\t    sum called 'hitcount' is incremented.  Keys and values\n"
+	"\t    correspond to fields in the event's format description.  Keys\n"
+	"\t    can be any field, or the special string 'stacktrace'.\n"
+	"\t    Compound keys consisting of up to two fields can be specified\n"
+	"\t    by the 'keys' keyword.  Values must correspond to numeric\n"
+	"\t    fields.  Sort keys consisting of up to two fields can be\n"
+	"\t    specified using the 'sort' keyword.  The sort direction can\n"
+	"\t    be modified by appending '.descending' or '.ascending' to a\n"
+	"\t    sort field.  The 'size' parameter can be used to specify more\n"
+	"\t    or fewer than the default 2048 entries for the hashtable size.\n"
+	"\t    If a hist trigger is given a name using the 'name' parameter,\n"
+	"\t    its histogram data will be shared with other triggers of the\n"
+	"\t    same name, and trigger hits will update this common data.\n\n"
+	"\t    Reading the 'hist' file for the event will dump the hash\n"
+	"\t    table in its entirety to stdout.  If there are multiple hist\n"
+	"\t    triggers attached to an event, there will be a table for each\n"
+	"\t    trigger in the output.  The table displayed for a named\n"
+	"\t    trigger will be the same as any other instance having the\n"
+	"\t    same name.  The default format used to display a given field\n"
+	"\t    can be modified by appending any of the following modifiers\n"
+	"\t    to the field name, as applicable:\n\n"
+	"\t            .hex        display a number as a hex value\n"
+	"\t            .sym        display an address as a symbol\n"
+	"\t            .sym-offset display an address as a symbol and offset\n"
+	"\t            .execname   display a common_pid as a program name\n"
+	"\t            .syscall    display a syscall id as a syscall name\n"
+	"\t            .log2       display log2 value rather than raw number\n"
+	"\t            .usecs      display a common_timestamp in microseconds\n\n"
+	"\t    The 'pause' parameter can be used to pause an existing hist\n"
+	"\t    trigger or to start a hist trigger but not log any events\n"
+	"\t    until told to do so.  'continue' can be used to start or\n"
+	"\t    restart a paused hist trigger.\n\n"
+	"\t    The 'clear' parameter will clear the contents of a running\n"
+	"\t    hist trigger and leave its current paused/active state\n"
+	"\t    unchanged.\n\n"
+	"\t    The enable_hist and disable_hist triggers can be used to\n"
+	"\t    have one event conditionally start and stop another event's\n"
+	"\t    already-attached hist trigger.  The syntax is analagous to\n"
+	"\t    the enable_event and disable_event triggers.\n"
+#endif
+;
+
+static ssize_t
+tracing_readme_read(struct file *filp, char __user *ubuf,
+		       size_t cnt, loff_t *ppos)
+{
+	return simple_read_from_buffer(ubuf, cnt, ppos,
+					readme_msg, strlen(readme_msg));
+}
+
+static const struct file_operations tracing_readme_fops = {
+	.open		= tracing_open_generic,
+	.read		= tracing_readme_read,
+	.llseek		= generic_file_llseek,
+};
+
+static void *saved_tgids_next(struct seq_file *m, void *v, loff_t *pos)
+{
+	int pid = ++(*pos);
+
+	return trace_find_tgid_ptr(pid);
+}
+
+static void *saved_tgids_start(struct seq_file *m, loff_t *pos)
+{
+	int pid = *pos;
+
+	return trace_find_tgid_ptr(pid);
+}
+
+static void saved_tgids_stop(struct seq_file *m, void *v)
+{
+}
+
+static int saved_tgids_show(struct seq_file *m, void *v)
+{
+	int *entry = (int *)v;
+	int pid = entry - tgid_map;
+	int tgid = *entry;
+
+	if (tgid == 0)
+		return SEQ_SKIP;
+
+	seq_printf(m, "%d %d\n", pid, tgid);
+	return 0;
+}
+
+static const struct seq_operations tracing_saved_tgids_seq_ops = {
+	.start		= saved_tgids_start,
+	.stop		= saved_tgids_stop,
+	.next		= saved_tgids_next,
+	.show		= saved_tgids_show,
+};
+
+static int tracing_saved_tgids_open(struct inode *inode, struct file *filp)
+{
+	if (tracing_disabled)
+		return -ENODEV;
+
+	return seq_open(filp, &tracing_saved_tgids_seq_ops);
+}
+
+
+static const struct file_operations tracing_saved_tgids_fops = {
+	.open		= tracing_saved_tgids_open,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.release	= seq_release,
+};
+
+static void *saved_cmdlines_next(struct seq_file *m, void *v, loff_t *pos)
+{
+	unsigned int *ptr = v;
+
+	if (*pos || m->count)
+		ptr++;
+
+	(*pos)++;
+
+	for (; ptr < &savedcmd->map_cmdline_to_pid[savedcmd->cmdline_num];
+	     ptr++) {
+		if (*ptr == -1 || *ptr == NO_CMDLINE_MAP)
+			continue;
+
+		return ptr;
+	}
+
+	return NULL;
+}
+
+static void *saved_cmdlines_start(struct seq_file *m, loff_t *pos)
+{
+	void *v;
+	loff_t l = 0;
+
+	preempt_disable();
+	arch_spin_lock(&trace_cmdline_lock);
+
+	v = &savedcmd->map_cmdline_to_pid[0];
+	while (l <= *pos) {
+		v = saved_cmdlines_next(m, v, &l);
+		if (!v)
+			return NULL;
+	}
+
+	return v;
+}
+
+static void saved_cmdlines_stop(struct seq_file *m, void *v)
+{
+	arch_spin_unlock(&trace_cmdline_lock);
+	preempt_enable();
+}
+
+static int saved_cmdlines_show(struct seq_file *m, void *v)
+{
+	char buf[TASK_COMM_LEN];
+	unsigned int *pid = v;
+
+	__trace_find_cmdline(*pid, buf);
+	seq_printf(m, "%d %s\n", *pid, buf);
+	return 0;
+}
+
+static const struct seq_operations tracing_saved_cmdlines_seq_ops = {
+	.start		= saved_cmdlines_start,
+	.next		= saved_cmdlines_next,
+	.stop		= saved_cmdlines_stop,
+	.show		= saved_cmdlines_show,
+};
+
+static int tracing_saved_cmdlines_open(struct inode *inode, struct file *filp)
+{
+	if (tracing_disabled)
+		return -ENODEV;
+
+	return seq_open(filp, &tracing_saved_cmdlines_seq_ops);
+}
+
+static const struct file_operations tracing_saved_cmdlines_fops = {
+	.open		= tracing_saved_cmdlines_open,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.release	= seq_release,
+};
+
+static ssize_t
+tracing_saved_cmdlines_size_read(struct file *filp, char __user *ubuf,
+				 size_t cnt, loff_t *ppos)
+{
+	char buf[64];
+	int r;
+
+	arch_spin_lock(&trace_cmdline_lock);
+	r = scnprintf(buf, sizeof(buf), "%u\n", savedcmd->cmdline_num);
+	arch_spin_unlock(&trace_cmdline_lock);
+
+	return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
+}
+
+static void free_saved_cmdlines_buffer(struct saved_cmdlines_buffer *s)
+{
+	kfree(s->saved_cmdlines);
+	kfree(s->map_cmdline_to_pid);
+	kfree(s);
+}
+
+static int tracing_resize_saved_cmdlines(unsigned int val)
+{
+	struct saved_cmdlines_buffer *s, *savedcmd_temp;
+
+	s = kmalloc(sizeof(*s), GFP_KERNEL);
+	if (!s)
+		return -ENOMEM;
+
+	if (allocate_cmdlines_buffer(val, s) < 0) {
+		kfree(s);
+		return -ENOMEM;
+	}
+
+	arch_spin_lock(&trace_cmdline_lock);
+	savedcmd_temp = savedcmd;
+	savedcmd = s;
+	arch_spin_unlock(&trace_cmdline_lock);
+	free_saved_cmdlines_buffer(savedcmd_temp);
+
+	return 0;
+}
+
+static ssize_t
+tracing_saved_cmdlines_size_write(struct file *filp, const char __user *ubuf,
+				  size_t cnt, loff_t *ppos)
+{
+	unsigned long val;
+	int ret;
+
+	ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
+	if (ret)
+		return ret;
+
+	/* must have at least 1 entry or less than PID_MAX_DEFAULT */
+	if (!val || val > PID_MAX_DEFAULT)
+		return -EINVAL;
+
+	ret = tracing_resize_saved_cmdlines((unsigned int)val);
+	if (ret < 0)
+		return ret;
+
+	*ppos += cnt;
+
+	return cnt;
+}
+
+static const struct file_operations tracing_saved_cmdlines_size_fops = {
+	.open		= tracing_open_generic,
+	.read		= tracing_saved_cmdlines_size_read,
+	.write		= tracing_saved_cmdlines_size_write,
+};
+
+#ifdef CONFIG_TRACE_EVAL_MAP_FILE
+static union trace_eval_map_item *
+update_eval_map(union trace_eval_map_item *ptr)
+{
+	if (!ptr->map.eval_string) {
+		if (ptr->tail.next) {
+			ptr = ptr->tail.next;
+			/* Set ptr to the next real item (skip head) */
+			ptr++;
+		} else
+			return NULL;
+	}
+	return ptr;
+}
+
+static void *eval_map_next(struct seq_file *m, void *v, loff_t *pos)
+{
+	union trace_eval_map_item *ptr = v;
+
+	/*
+	 * Paranoid! If ptr points to end, we don't want to increment past it.
+	 * This really should never happen.
+	 */
+	ptr = update_eval_map(ptr);
+	if (WARN_ON_ONCE(!ptr))
+		return NULL;
+
+	ptr++;
+
+	(*pos)++;
+
+	ptr = update_eval_map(ptr);
+
+	return ptr;
+}
+
+static void *eval_map_start(struct seq_file *m, loff_t *pos)
+{
+	union trace_eval_map_item *v;
+	loff_t l = 0;
+
+	mutex_lock(&trace_eval_mutex);
+
+	v = trace_eval_maps;
+	if (v)
+		v++;
+
+	while (v && l < *pos) {
+		v = eval_map_next(m, v, &l);
+	}
+
+	return v;
+}
+
+static void eval_map_stop(struct seq_file *m, void *v)
+{
+	mutex_unlock(&trace_eval_mutex);
+}
+
+static int eval_map_show(struct seq_file *m, void *v)
+{
+	union trace_eval_map_item *ptr = v;
+
+	seq_printf(m, "%s %ld (%s)\n",
+		   ptr->map.eval_string, ptr->map.eval_value,
+		   ptr->map.system);
+
+	return 0;
+}
+
+static const struct seq_operations tracing_eval_map_seq_ops = {
+	.start		= eval_map_start,
+	.next		= eval_map_next,
+	.stop		= eval_map_stop,
+	.show		= eval_map_show,
+};
+
+static int tracing_eval_map_open(struct inode *inode, struct file *filp)
+{
+	if (tracing_disabled)
+		return -ENODEV;
+
+	return seq_open(filp, &tracing_eval_map_seq_ops);
+}
+
+static const struct file_operations tracing_eval_map_fops = {
+	.open		= tracing_eval_map_open,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.release	= seq_release,
+};
+
+static inline union trace_eval_map_item *
+trace_eval_jmp_to_tail(union trace_eval_map_item *ptr)
+{
+	/* Return tail of array given the head */
+	return ptr + ptr->head.length + 1;
+}
+
+static void
+trace_insert_eval_map_file(struct module *mod, struct trace_eval_map **start,
+			   int len)
+{
+	struct trace_eval_map **stop;
+	struct trace_eval_map **map;
+	union trace_eval_map_item *map_array;
+	union trace_eval_map_item *ptr;
+
+	stop = start + len;
+
+	/*
+	 * The trace_eval_maps contains the map plus a head and tail item,
+	 * where the head holds the module and length of array, and the
+	 * tail holds a pointer to the next list.
+	 */
+	map_array = kmalloc_array(len + 2, sizeof(*map_array), GFP_KERNEL);
+	if (!map_array) {
+		pr_warn("Unable to allocate trace eval mapping\n");
+		return;
+	}
+
+	mutex_lock(&trace_eval_mutex);
+
+	if (!trace_eval_maps)
+		trace_eval_maps = map_array;
+	else {
+		ptr = trace_eval_maps;
+		for (;;) {
+			ptr = trace_eval_jmp_to_tail(ptr);
+			if (!ptr->tail.next)
+				break;
+			ptr = ptr->tail.next;
+
+		}
+		ptr->tail.next = map_array;
+	}
+	map_array->head.mod = mod;
+	map_array->head.length = len;
+	map_array++;
+
+	for (map = start; (unsigned long)map < (unsigned long)stop; map++) {
+		map_array->map = **map;
+		map_array++;
+	}
+	memset(map_array, 0, sizeof(*map_array));
+
+	mutex_unlock(&trace_eval_mutex);
+}
+
+static void trace_create_eval_file(struct dentry *d_tracer)
+{
+	trace_create_file("eval_map", 0444, d_tracer,
+			  NULL, &tracing_eval_map_fops);
+}
+
+#else /* CONFIG_TRACE_EVAL_MAP_FILE */
+static inline void trace_create_eval_file(struct dentry *d_tracer) { }
+static inline void trace_insert_eval_map_file(struct module *mod,
+			      struct trace_eval_map **start, int len) { }
+#endif /* !CONFIG_TRACE_EVAL_MAP_FILE */
+
+static void trace_insert_eval_map(struct module *mod,
+				  struct trace_eval_map **start, int len)
+{
+	struct trace_eval_map **map;
+
+	if (len <= 0)
+		return;
+
+	map = start;
+
+	trace_event_eval_update(map, len);
+
+	trace_insert_eval_map_file(mod, start, len);
+}
+
+static ssize_t
+tracing_set_trace_read(struct file *filp, char __user *ubuf,
+		       size_t cnt, loff_t *ppos)
+{
+	struct trace_array *tr = filp->private_data;
+	char buf[MAX_TRACER_SIZE+2];
+	int r;
+
+	mutex_lock(&trace_types_lock);
+	r = sprintf(buf, "%s\n", tr->current_trace->name);
+	mutex_unlock(&trace_types_lock);
+
+	return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
+}
+
+int tracer_init(struct tracer *t, struct trace_array *tr)
+{
+	tracing_reset_online_cpus(&tr->trace_buffer);
+	return t->init(tr);
+}
+
+static void set_buffer_entries(struct trace_buffer *buf, unsigned long val)
+{
+	int cpu;
+
+	for_each_tracing_cpu(cpu)
+		per_cpu_ptr(buf->data, cpu)->entries = val;
+}
+
+#ifdef CONFIG_TRACER_MAX_TRACE
+/* resize @tr's buffer to the size of @size_tr's entries */
+static int resize_buffer_duplicate_size(struct trace_buffer *trace_buf,
+					struct trace_buffer *size_buf, int cpu_id)
+{
+	int cpu, ret = 0;
+
+	if (cpu_id == RING_BUFFER_ALL_CPUS) {
+		for_each_tracing_cpu(cpu) {
+			ret = ring_buffer_resize(trace_buf->buffer,
+				 per_cpu_ptr(size_buf->data, cpu)->entries, cpu);
+			if (ret < 0)
+				break;
+			per_cpu_ptr(trace_buf->data, cpu)->entries =
+				per_cpu_ptr(size_buf->data, cpu)->entries;
+		}
+	} else {
+		ret = ring_buffer_resize(trace_buf->buffer,
+				 per_cpu_ptr(size_buf->data, cpu_id)->entries, cpu_id);
+		if (ret == 0)
+			per_cpu_ptr(trace_buf->data, cpu_id)->entries =
+				per_cpu_ptr(size_buf->data, cpu_id)->entries;
+	}
+
+	return ret;
+}
+#endif /* CONFIG_TRACER_MAX_TRACE */
+
+static int __tracing_resize_ring_buffer(struct trace_array *tr,
+					unsigned long size, int cpu)
+{
+	int ret;
+
+	/*
+	 * If kernel or user changes the size of the ring buffer
+	 * we use the size that was given, and we can forget about
+	 * expanding it later.
+	 */
+	ring_buffer_expanded = true;
+
+	/* May be called before buffers are initialized */
+	if (!tr->trace_buffer.buffer)
+		return 0;
+
+	ret = ring_buffer_resize(tr->trace_buffer.buffer, size, cpu);
+	if (ret < 0)
+		return ret;
+
+#ifdef CONFIG_TRACER_MAX_TRACE
+	if (!(tr->flags & TRACE_ARRAY_FL_GLOBAL) ||
+	    !tr->current_trace->use_max_tr)
+		goto out;
+
+	ret = ring_buffer_resize(tr->max_buffer.buffer, size, cpu);
+	if (ret < 0) {
+		int r = resize_buffer_duplicate_size(&tr->trace_buffer,
+						     &tr->trace_buffer, cpu);
+		if (r < 0) {
+			/*
+			 * AARGH! We are left with different
+			 * size max buffer!!!!
+			 * The max buffer is our "snapshot" buffer.
+			 * When a tracer needs a snapshot (one of the
+			 * latency tracers), it swaps the max buffer
+			 * with the saved snap shot. We succeeded to
+			 * update the size of the main buffer, but failed to
+			 * update the size of the max buffer. But when we tried
+			 * to reset the main buffer to the original size, we
+			 * failed there too. This is very unlikely to
+			 * happen, but if it does, warn and kill all
+			 * tracing.
+			 */
+			WARN_ON(1);
+			tracing_disabled = 1;
+		}
+		return ret;
+	}
+
+	if (cpu == RING_BUFFER_ALL_CPUS)
+		set_buffer_entries(&tr->max_buffer, size);
+	else
+		per_cpu_ptr(tr->max_buffer.data, cpu)->entries = size;
+
+ out:
+#endif /* CONFIG_TRACER_MAX_TRACE */
+
+	if (cpu == RING_BUFFER_ALL_CPUS)
+		set_buffer_entries(&tr->trace_buffer, size);
+	else
+		per_cpu_ptr(tr->trace_buffer.data, cpu)->entries = size;
+
+	return ret;
+}
+
+static ssize_t tracing_resize_ring_buffer(struct trace_array *tr,
+					  unsigned long size, int cpu_id)
+{
+	int ret = size;
+
+	mutex_lock(&trace_types_lock);
+
+	if (cpu_id != RING_BUFFER_ALL_CPUS) {
+		/* make sure, this cpu is enabled in the mask */
+		if (!cpumask_test_cpu(cpu_id, tracing_buffer_mask)) {
+			ret = -EINVAL;
+			goto out;
+		}
+	}
+
+	ret = __tracing_resize_ring_buffer(tr, size, cpu_id);
+	if (ret < 0)
+		ret = -ENOMEM;
+
+out:
+	mutex_unlock(&trace_types_lock);
+
+	return ret;
+}
+
+
+/**
+ * tracing_update_buffers - used by tracing facility to expand ring buffers
+ *
+ * To save on memory when the tracing is never used on a system with it
+ * configured in. The ring buffers are set to a minimum size. But once
+ * a user starts to use the tracing facility, then they need to grow
+ * to their default size.
+ *
+ * This function is to be called when a tracer is about to be used.
+ */
+int tracing_update_buffers(void)
+{
+	int ret = 0;
+
+	mutex_lock(&trace_types_lock);
+	if (!ring_buffer_expanded)
+		ret = __tracing_resize_ring_buffer(&global_trace, trace_buf_size,
+						RING_BUFFER_ALL_CPUS);
+	mutex_unlock(&trace_types_lock);
+
+	return ret;
+}
+
+struct trace_option_dentry;
+
+static void
+create_trace_option_files(struct trace_array *tr, struct tracer *tracer);
+
+/*
+ * Used to clear out the tracer before deletion of an instance.
+ * Must have trace_types_lock held.
+ */
+static void tracing_set_nop(struct trace_array *tr)
+{
+	if (tr->current_trace == &nop_trace)
+		return;
+	
+	tr->current_trace->enabled--;
+
+	if (tr->current_trace->reset)
+		tr->current_trace->reset(tr);
+
+	tr->current_trace = &nop_trace;
+}
+
+static bool tracer_options_updated;
+
+static void add_tracer_options(struct trace_array *tr, struct tracer *t)
+{
+	/* Only enable if the directory has been created already. */
+	if (!tr->dir)
+		return;
+
+	/* Only create trace option files after update_tracer_options finish */
+	if (!tracer_options_updated)
+		return;
+
+	create_trace_option_files(tr, t);
+}
+
+static int tracing_set_tracer(struct trace_array *tr, const char *buf)
+{
+	struct tracer *t;
+#ifdef CONFIG_TRACER_MAX_TRACE
+	bool had_max_tr;
+#endif
+	int ret = 0;
+
+	mutex_lock(&trace_types_lock);
+
+	if (!ring_buffer_expanded) {
+		ret = __tracing_resize_ring_buffer(tr, trace_buf_size,
+						RING_BUFFER_ALL_CPUS);
+		if (ret < 0)
+			goto out;
+		ret = 0;
+	}
+
+	for (t = trace_types; t; t = t->next) {
+		if (strcmp(t->name, buf) == 0)
+			break;
+	}
+	if (!t) {
+		ret = -EINVAL;
+		goto out;
+	}
+	if (t == tr->current_trace)
+		goto out;
+
+	/* Some tracers won't work on kernel command line */
+	if (system_state < SYSTEM_RUNNING && t->noboot) {
+		pr_warn("Tracer '%s' is not allowed on command line, ignored\n",
+			t->name);
+		goto out;
+	}
+
+	/* Some tracers are only allowed for the top level buffer */
+	if (!trace_ok_for_array(t, tr)) {
+		ret = -EINVAL;
+		goto out;
+	}
+
+	/* If trace pipe files are being read, we can't change the tracer */
+	if (tr->current_trace->ref) {
+		ret = -EBUSY;
+		goto out;
+	}
+
+	trace_branch_disable();
+
+	tr->current_trace->enabled--;
+
+	if (tr->current_trace->reset)
+		tr->current_trace->reset(tr);
+
+	/* Current trace needs to be nop_trace before synchronize_sched */
+	tr->current_trace = &nop_trace;
+
+#ifdef CONFIG_TRACER_MAX_TRACE
+	had_max_tr = tr->allocated_snapshot;
+
+	if (had_max_tr && !t->use_max_tr) {
+		/*
+		 * We need to make sure that the update_max_tr sees that
+		 * current_trace changed to nop_trace to keep it from
+		 * swapping the buffers after we resize it.
+		 * The update_max_tr is called from interrupts disabled
+		 * so a synchronized_sched() is sufficient.
+		 */
+		synchronize_sched();
+		free_snapshot(tr);
+	}
+#endif
+
+#ifdef CONFIG_TRACER_MAX_TRACE
+	if (t->use_max_tr && !had_max_tr) {
+		ret = tracing_alloc_snapshot_instance(tr);
+		if (ret < 0)
+			goto out;
+	}
+#endif
+
+	if (t->init) {
+		ret = tracer_init(t, tr);
+		if (ret)
+			goto out;
+	}
+
+	tr->current_trace = t;
+	tr->current_trace->enabled++;
+	trace_branch_enable(tr);
+ out:
+	mutex_unlock(&trace_types_lock);
+
+	return ret;
+}
+
+static ssize_t
+tracing_set_trace_write(struct file *filp, const char __user *ubuf,
+			size_t cnt, loff_t *ppos)
+{
+	struct trace_array *tr = filp->private_data;
+	char buf[MAX_TRACER_SIZE+1];
+	int i;
+	size_t ret;
+	int err;
+
+	ret = cnt;
+
+	if (cnt > MAX_TRACER_SIZE)
+		cnt = MAX_TRACER_SIZE;
+
+	if (copy_from_user(buf, ubuf, cnt))
+		return -EFAULT;
+
+	buf[cnt] = 0;
+
+	/* strip ending whitespace. */
+	for (i = cnt - 1; i > 0 && isspace(buf[i]); i--)
+		buf[i] = 0;
+
+	err = tracing_set_tracer(tr, buf);
+	if (err)
+		return err;
+
+	*ppos += ret;
+
+	return ret;
+}
+
+static ssize_t
+tracing_nsecs_read(unsigned long *ptr, char __user *ubuf,
+		   size_t cnt, loff_t *ppos)
+{
+	char buf[64];
+	int r;
+
+	r = snprintf(buf, sizeof(buf), "%ld\n",
+		     *ptr == (unsigned long)-1 ? -1 : nsecs_to_usecs(*ptr));
+	if (r > sizeof(buf))
+		r = sizeof(buf);
+	return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
+}
+
+static ssize_t
+tracing_nsecs_write(unsigned long *ptr, const char __user *ubuf,
+		    size_t cnt, loff_t *ppos)
+{
+	unsigned long val;
+	int ret;
+
+	ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
+	if (ret)
+		return ret;
+
+	*ptr = val * 1000;
+
+	return cnt;
+}
+
+static ssize_t
+tracing_thresh_read(struct file *filp, char __user *ubuf,
+		    size_t cnt, loff_t *ppos)
+{
+	return tracing_nsecs_read(&tracing_thresh, ubuf, cnt, ppos);
+}
+
+static ssize_t
+tracing_thresh_write(struct file *filp, const char __user *ubuf,
+		     size_t cnt, loff_t *ppos)
+{
+	struct trace_array *tr = filp->private_data;
+	int ret;
+
+	mutex_lock(&trace_types_lock);
+	ret = tracing_nsecs_write(&tracing_thresh, ubuf, cnt, ppos);
+	if (ret < 0)
+		goto out;
+
+	if (tr->current_trace->update_thresh) {
+		ret = tr->current_trace->update_thresh(tr);
+		if (ret < 0)
+			goto out;
+	}
+
+	ret = cnt;
+out:
+	mutex_unlock(&trace_types_lock);
+
+	return ret;
+}
+
+#if defined(CONFIG_TRACER_MAX_TRACE) || defined(CONFIG_HWLAT_TRACER)
+
+static ssize_t
+tracing_max_lat_read(struct file *filp, char __user *ubuf,
+		     size_t cnt, loff_t *ppos)
+{
+	return tracing_nsecs_read(filp->private_data, ubuf, cnt, ppos);
+}
+
+static ssize_t
+tracing_max_lat_write(struct file *filp, const char __user *ubuf,
+		      size_t cnt, loff_t *ppos)
+{
+	return tracing_nsecs_write(filp->private_data, ubuf, cnt, ppos);
+}
+
+#endif
+
+static int tracing_open_pipe(struct inode *inode, struct file *filp)
+{
+	struct trace_array *tr = inode->i_private;
+	struct trace_iterator *iter;
+	int ret = 0;
+
+	if (tracing_disabled)
+		return -ENODEV;
+
+	if (trace_array_get(tr) < 0)
+		return -ENODEV;
+
+	mutex_lock(&trace_types_lock);
+
+	/* create a buffer to store the information to pass to userspace */
+	iter = kzalloc(sizeof(*iter), GFP_KERNEL);
+	if (!iter) {
+		ret = -ENOMEM;
+		__trace_array_put(tr);
+		goto out;
+	}
+
+	trace_seq_init(&iter->seq);
+	iter->trace = tr->current_trace;
+
+	if (!alloc_cpumask_var(&iter->started, GFP_KERNEL)) {
+		ret = -ENOMEM;
+		goto fail;
+	}
+
+	/* trace pipe does not show start of buffer */
+	cpumask_setall(iter->started);
+
+	if (tr->trace_flags & TRACE_ITER_LATENCY_FMT)
+		iter->iter_flags |= TRACE_FILE_LAT_FMT;
+
+	/* Output in nanoseconds only if we are using a clock in nanoseconds. */
+	if (trace_clocks[tr->clock_id].in_ns)
+		iter->iter_flags |= TRACE_FILE_TIME_IN_NS;
+
+	iter->tr = tr;
+	iter->trace_buffer = &tr->trace_buffer;
+	iter->cpu_file = tracing_get_cpu(inode);
+	mutex_init(&iter->mutex);
+	filp->private_data = iter;
+
+	if (iter->trace->pipe_open)
+		iter->trace->pipe_open(iter);
+
+	nonseekable_open(inode, filp);
+
+	tr->current_trace->ref++;
+out:
+	mutex_unlock(&trace_types_lock);
+	return ret;
+
+fail:
+	kfree(iter);
+	__trace_array_put(tr);
+	mutex_unlock(&trace_types_lock);
+	return ret;
+}
+
+static int tracing_release_pipe(struct inode *inode, struct file *file)
+{
+	struct trace_iterator *iter = file->private_data;
+	struct trace_array *tr = inode->i_private;
+
+	mutex_lock(&trace_types_lock);
+
+	tr->current_trace->ref--;
+
+	if (iter->trace->pipe_close)
+		iter->trace->pipe_close(iter);
+
+	mutex_unlock(&trace_types_lock);
+
+	free_cpumask_var(iter->started);
+	mutex_destroy(&iter->mutex);
+	kfree(iter);
+
+	trace_array_put(tr);
+
+	return 0;
+}
+
+static __poll_t
+trace_poll(struct trace_iterator *iter, struct file *filp, poll_table *poll_table)
+{
+	struct trace_array *tr = iter->tr;
+
+	/* Iterators are static, they should be filled or empty */
+	if (trace_buffer_iter(iter, iter->cpu_file))
+		return EPOLLIN | EPOLLRDNORM;
+
+	if (tr->trace_flags & TRACE_ITER_BLOCK)
+		/*
+		 * Always select as readable when in blocking mode
+		 */
+		return EPOLLIN | EPOLLRDNORM;
+	else
+		return ring_buffer_poll_wait(iter->trace_buffer->buffer, iter->cpu_file,
+					     filp, poll_table);
+}
+
+static __poll_t
+tracing_poll_pipe(struct file *filp, poll_table *poll_table)
+{
+	struct trace_iterator *iter = filp->private_data;
+
+	return trace_poll(iter, filp, poll_table);
+}
+
+/* Must be called with iter->mutex held. */
+static int tracing_wait_pipe(struct file *filp)
+{
+	struct trace_iterator *iter = filp->private_data;
+	int ret;
+
+	while (trace_empty(iter)) {
+
+		if ((filp->f_flags & O_NONBLOCK)) {
+			return -EAGAIN;
+		}
+
+		/*
+		 * We block until we read something and tracing is disabled.
+		 * We still block if tracing is disabled, but we have never
+		 * read anything. This allows a user to cat this file, and
+		 * then enable tracing. But after we have read something,
+		 * we give an EOF when tracing is again disabled.
+		 *
+		 * iter->pos will be 0 if we haven't read anything.
+		 */
+		if (!tracer_tracing_is_on(iter->tr) && iter->pos)
+			break;
+
+		mutex_unlock(&iter->mutex);
+
+		ret = wait_on_pipe(iter, false);
+
+		mutex_lock(&iter->mutex);
+
+		if (ret)
+			return ret;
+	}
+
+	return 1;
+}
+
+/*
+ * Consumer reader.
+ */
+static ssize_t
+tracing_read_pipe(struct file *filp, char __user *ubuf,
+		  size_t cnt, loff_t *ppos)
+{
+	struct trace_iterator *iter = filp->private_data;
+	ssize_t sret;
+
+	/*
+	 * Avoid more than one consumer on a single file descriptor
+	 * This is just a matter of traces coherency, the ring buffer itself
+	 * is protected.
+	 */
+	mutex_lock(&iter->mutex);
+
+	/* return any leftover data */
+	sret = trace_seq_to_user(&iter->seq, ubuf, cnt);
+	if (sret != -EBUSY)
+		goto out;
+
+	trace_seq_init(&iter->seq);
+
+	if (iter->trace->read) {
+		sret = iter->trace->read(iter, filp, ubuf, cnt, ppos);
+		if (sret)
+			goto out;
+	}
+
+waitagain:
+	sret = tracing_wait_pipe(filp);
+	if (sret <= 0)
+		goto out;
+
+	/* stop when tracing is finished */
+	if (trace_empty(iter)) {
+		sret = 0;
+		goto out;
+	}
+
+	if (cnt >= PAGE_SIZE)
+		cnt = PAGE_SIZE - 1;
+
+	/* reset all but tr, trace, and overruns */
+	memset(&iter->seq, 0,
+	       sizeof(struct trace_iterator) -
+	       offsetof(struct trace_iterator, seq));
+	cpumask_clear(iter->started);
+	trace_seq_init(&iter->seq);
+	iter->pos = -1;
+
+	trace_event_read_lock();
+	trace_access_lock(iter->cpu_file);
+	while (trace_find_next_entry_inc(iter) != NULL) {
+		enum print_line_t ret;
+		int save_len = iter->seq.seq.len;
+
+		ret = print_trace_line(iter);
+		if (ret == TRACE_TYPE_PARTIAL_LINE) {
+			/* don't print partial lines */
+			iter->seq.seq.len = save_len;
+			break;
+		}
+		if (ret != TRACE_TYPE_NO_CONSUME)
+			trace_consume(iter);
+
+		if (trace_seq_used(&iter->seq) >= cnt)
+			break;
+
+		/*
+		 * Setting the full flag means we reached the trace_seq buffer
+		 * size and we should leave by partial output condition above.
+		 * One of the trace_seq_* functions is not used properly.
+		 */
+		WARN_ONCE(iter->seq.full, "full flag set for trace type %d",
+			  iter->ent->type);
+	}
+	trace_access_unlock(iter->cpu_file);
+	trace_event_read_unlock();
+
+	/* Now copy what we have to the user */
+	sret = trace_seq_to_user(&iter->seq, ubuf, cnt);
+	if (iter->seq.seq.readpos >= trace_seq_used(&iter->seq))
+		trace_seq_init(&iter->seq);
+
+	/*
+	 * If there was nothing to send to user, in spite of consuming trace
+	 * entries, go back to wait for more entries.
+	 */
+	if (sret == -EBUSY)
+		goto waitagain;
+
+out:
+	mutex_unlock(&iter->mutex);
+
+	return sret;
+}
+
+static void tracing_spd_release_pipe(struct splice_pipe_desc *spd,
+				     unsigned int idx)
+{
+	__free_page(spd->pages[idx]);
+}
+
+static const struct pipe_buf_operations tracing_pipe_buf_ops = {
+	.can_merge		= 0,
+	.confirm		= generic_pipe_buf_confirm,
+	.release		= generic_pipe_buf_release,
+	.steal			= generic_pipe_buf_steal,
+	.get			= generic_pipe_buf_get,
+};
+
+static size_t
+tracing_fill_pipe_page(size_t rem, struct trace_iterator *iter)
+{
+	size_t count;
+	int save_len;
+	int ret;
+
+	/* Seq buffer is page-sized, exactly what we need. */
+	for (;;) {
+		save_len = iter->seq.seq.len;
+		ret = print_trace_line(iter);
+
+		if (trace_seq_has_overflowed(&iter->seq)) {
+			iter->seq.seq.len = save_len;
+			break;
+		}
+
+		/*
+		 * This should not be hit, because it should only
+		 * be set if the iter->seq overflowed. But check it
+		 * anyway to be safe.
+		 */
+		if (ret == TRACE_TYPE_PARTIAL_LINE) {
+			iter->seq.seq.len = save_len;
+			break;
+		}
+
+		count = trace_seq_used(&iter->seq) - save_len;
+		if (rem < count) {
+			rem = 0;
+			iter->seq.seq.len = save_len;
+			break;
+		}
+
+		if (ret != TRACE_TYPE_NO_CONSUME)
+			trace_consume(iter);
+		rem -= count;
+		if (!trace_find_next_entry_inc(iter))	{
+			rem = 0;
+			iter->ent = NULL;
+			break;
+		}
+	}
+
+	return rem;
+}
+
+static ssize_t tracing_splice_read_pipe(struct file *filp,
+					loff_t *ppos,
+					struct pipe_inode_info *pipe,
+					size_t len,
+					unsigned int flags)
+{
+	struct page *pages_def[PIPE_DEF_BUFFERS];
+	struct partial_page partial_def[PIPE_DEF_BUFFERS];
+	struct trace_iterator *iter = filp->private_data;
+	struct splice_pipe_desc spd = {
+		.pages		= pages_def,
+		.partial	= partial_def,
+		.nr_pages	= 0, /* This gets updated below. */
+		.nr_pages_max	= PIPE_DEF_BUFFERS,
+		.ops		= &tracing_pipe_buf_ops,
+		.spd_release	= tracing_spd_release_pipe,
+	};
+	ssize_t ret;
+	size_t rem;
+	unsigned int i;
+
+	if (splice_grow_spd(pipe, &spd))
+		return -ENOMEM;
+
+	mutex_lock(&iter->mutex);
+
+	if (iter->trace->splice_read) {
+		ret = iter->trace->splice_read(iter, filp,
+					       ppos, pipe, len, flags);
+		if (ret)
+			goto out_err;
+	}
+
+	ret = tracing_wait_pipe(filp);
+	if (ret <= 0)
+		goto out_err;
+
+	if (!iter->ent && !trace_find_next_entry_inc(iter)) {
+		ret = -EFAULT;
+		goto out_err;
+	}
+
+	trace_event_read_lock();
+	trace_access_lock(iter->cpu_file);
+
+	/* Fill as many pages as possible. */
+	for (i = 0, rem = len; i < spd.nr_pages_max && rem; i++) {
+		spd.pages[i] = alloc_page(GFP_KERNEL);
+		if (!spd.pages[i])
+			break;
+
+		rem = tracing_fill_pipe_page(rem, iter);
+
+		/* Copy the data into the page, so we can start over. */
+		ret = trace_seq_to_buffer(&iter->seq,
+					  page_address(spd.pages[i]),
+					  trace_seq_used(&iter->seq));
+		if (ret < 0) {
+			__free_page(spd.pages[i]);
+			break;
+		}
+		spd.partial[i].offset = 0;
+		spd.partial[i].len = trace_seq_used(&iter->seq);
+
+		trace_seq_init(&iter->seq);
+	}
+
+	trace_access_unlock(iter->cpu_file);
+	trace_event_read_unlock();
+	mutex_unlock(&iter->mutex);
+
+	spd.nr_pages = i;
+
+	if (i)
+		ret = splice_to_pipe(pipe, &spd);
+	else
+		ret = 0;
+out:
+	splice_shrink_spd(&spd);
+	return ret;
+
+out_err:
+	mutex_unlock(&iter->mutex);
+	goto out;
+}
+
+static ssize_t
+tracing_entries_read(struct file *filp, char __user *ubuf,
+		     size_t cnt, loff_t *ppos)
+{
+	struct inode *inode = file_inode(filp);
+	struct trace_array *tr = inode->i_private;
+	int cpu = tracing_get_cpu(inode);
+	char buf[64];
+	int r = 0;
+	ssize_t ret;
+
+	mutex_lock(&trace_types_lock);
+
+	if (cpu == RING_BUFFER_ALL_CPUS) {
+		int cpu, buf_size_same;
+		unsigned long size;
+
+		size = 0;
+		buf_size_same = 1;
+		/* check if all cpu sizes are same */
+		for_each_tracing_cpu(cpu) {
+			/* fill in the size from first enabled cpu */
+			if (size == 0)
+				size = per_cpu_ptr(tr->trace_buffer.data, cpu)->entries;
+			if (size != per_cpu_ptr(tr->trace_buffer.data, cpu)->entries) {
+				buf_size_same = 0;
+				break;
+			}
+		}
+
+		if (buf_size_same) {
+			if (!ring_buffer_expanded)
+				r = sprintf(buf, "%lu (expanded: %lu)\n",
+					    size >> 10,
+					    trace_buf_size >> 10);
+			else
+				r = sprintf(buf, "%lu\n", size >> 10);
+		} else
+			r = sprintf(buf, "X\n");
+	} else
+		r = sprintf(buf, "%lu\n", per_cpu_ptr(tr->trace_buffer.data, cpu)->entries >> 10);
+
+	mutex_unlock(&trace_types_lock);
+
+	ret = simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
+	return ret;
+}
+
+static ssize_t
+tracing_entries_write(struct file *filp, const char __user *ubuf,
+		      size_t cnt, loff_t *ppos)
+{
+	struct inode *inode = file_inode(filp);
+	struct trace_array *tr = inode->i_private;
+	unsigned long val;
+	int ret;
+
+	ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
+	if (ret)
+		return ret;
+
+	/* must have at least 1 entry */
+	if (!val)
+		return -EINVAL;
+
+	/* value is in KB */
+	val <<= 10;
+	ret = tracing_resize_ring_buffer(tr, val, tracing_get_cpu(inode));
+	if (ret < 0)
+		return ret;
+
+	*ppos += cnt;
+
+	return cnt;
+}
+
+static ssize_t
+tracing_total_entries_read(struct file *filp, char __user *ubuf,
+				size_t cnt, loff_t *ppos)
+{
+	struct trace_array *tr = filp->private_data;
+	char buf[64];
+	int r, cpu;
+	unsigned long size = 0, expanded_size = 0;
+
+	mutex_lock(&trace_types_lock);
+	for_each_tracing_cpu(cpu) {
+		size += per_cpu_ptr(tr->trace_buffer.data, cpu)->entries >> 10;
+		if (!ring_buffer_expanded)
+			expanded_size += trace_buf_size >> 10;
+	}
+	if (ring_buffer_expanded)
+		r = sprintf(buf, "%lu\n", size);
+	else
+		r = sprintf(buf, "%lu (expanded: %lu)\n", size, expanded_size);
+	mutex_unlock(&trace_types_lock);
+
+	return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
+}
+
+static ssize_t
+tracing_free_buffer_write(struct file *filp, const char __user *ubuf,
+			  size_t cnt, loff_t *ppos)
+{
+	/*
+	 * There is no need to read what the user has written, this function
+	 * is just to make sure that there is no error when "echo" is used
+	 */
+
+	*ppos += cnt;
+
+	return cnt;
+}
+
+static int
+tracing_free_buffer_release(struct inode *inode, struct file *filp)
+{
+	struct trace_array *tr = inode->i_private;
+
+	/* disable tracing ? */
+	if (tr->trace_flags & TRACE_ITER_STOP_ON_FREE)
+		tracer_tracing_off(tr);
+	/* resize the ring buffer to 0 */
+	tracing_resize_ring_buffer(tr, 0, RING_BUFFER_ALL_CPUS);
+
+	trace_array_put(tr);
+
+	return 0;
+}
+
+static ssize_t
+tracing_mark_write(struct file *filp, const char __user *ubuf,
+					size_t cnt, loff_t *fpos)
+{
+	struct trace_array *tr = filp->private_data;
+	struct ring_buffer_event *event;
+	enum event_trigger_type tt = ETT_NONE;
+	struct ring_buffer *buffer;
+	struct print_entry *entry;
+	unsigned long irq_flags;
+	const char faulted[] = "<faulted>";
+	ssize_t written;
+	int size;
+	int len;
+
+/* Used in tracing_mark_raw_write() as well */
+#define FAULTED_SIZE (sizeof(faulted) - 1) /* '\0' is already accounted for */
+
+	if (tracing_disabled)
+		return -EINVAL;
+
+	if (!(tr->trace_flags & TRACE_ITER_MARKERS))
+		return -EINVAL;
+
+	if (cnt > TRACE_BUF_SIZE)
+		cnt = TRACE_BUF_SIZE;
+
+	BUILD_BUG_ON(TRACE_BUF_SIZE >= PAGE_SIZE);
+
+	local_save_flags(irq_flags);
+	size = sizeof(*entry) + cnt + 2; /* add '\0' and possible '\n' */
+
+	/* If less than "<faulted>", then make sure we can still add that */
+	if (cnt < FAULTED_SIZE)
+		size += FAULTED_SIZE - cnt;
+
+	buffer = tr->trace_buffer.buffer;
+	event = __trace_buffer_lock_reserve(buffer, TRACE_PRINT, size,
+					    irq_flags, preempt_count());
+	if (unlikely(!event))
+		/* Ring buffer disabled, return as if not open for write */
+		return -EBADF;
+
+	entry = ring_buffer_event_data(event);
+	entry->ip = _THIS_IP_;
+
+	len = __copy_from_user_inatomic(&entry->buf, ubuf, cnt);
+	if (len) {
+		memcpy(&entry->buf, faulted, FAULTED_SIZE);
+		cnt = FAULTED_SIZE;
+		written = -EFAULT;
+	} else
+		written = cnt;
+	len = cnt;
+
+	if (tr->trace_marker_file && !list_empty(&tr->trace_marker_file->triggers)) {
+		/* do not add \n before testing triggers, but add \0 */
+		entry->buf[cnt] = '\0';
+		tt = event_triggers_call(tr->trace_marker_file, entry, event);
+	}
+
+	if (entry->buf[cnt - 1] != '\n') {
+		entry->buf[cnt] = '\n';
+		entry->buf[cnt + 1] = '\0';
+	} else
+		entry->buf[cnt] = '\0';
+
+	__buffer_unlock_commit(buffer, event);
+
+	if (tt)
+		event_triggers_post_call(tr->trace_marker_file, tt);
+
+	if (written > 0)
+		*fpos += written;
+
+	return written;
+}
+
+/* Limit it for now to 3K (including tag) */
+#define RAW_DATA_MAX_SIZE (1024*3)
+
+static ssize_t
+tracing_mark_raw_write(struct file *filp, const char __user *ubuf,
+					size_t cnt, loff_t *fpos)
+{
+	struct trace_array *tr = filp->private_data;
+	struct ring_buffer_event *event;
+	struct ring_buffer *buffer;
+	struct raw_data_entry *entry;
+	const char faulted[] = "<faulted>";
+	unsigned long irq_flags;
+	ssize_t written;
+	int size;
+	int len;
+
+#define FAULT_SIZE_ID (FAULTED_SIZE + sizeof(int))
+
+	if (tracing_disabled)
+		return -EINVAL;
+
+	if (!(tr->trace_flags & TRACE_ITER_MARKERS))
+		return -EINVAL;
+
+	/* The marker must at least have a tag id */
+	if (cnt < sizeof(unsigned int) || cnt > RAW_DATA_MAX_SIZE)
+		return -EINVAL;
+
+	if (cnt > TRACE_BUF_SIZE)
+		cnt = TRACE_BUF_SIZE;
+
+	BUILD_BUG_ON(TRACE_BUF_SIZE >= PAGE_SIZE);
+
+	local_save_flags(irq_flags);
+	size = sizeof(*entry) + cnt;
+	if (cnt < FAULT_SIZE_ID)
+		size += FAULT_SIZE_ID - cnt;
+
+	buffer = tr->trace_buffer.buffer;
+	event = __trace_buffer_lock_reserve(buffer, TRACE_RAW_DATA, size,
+					    irq_flags, preempt_count());
+	if (!event)
+		/* Ring buffer disabled, return as if not open for write */
+		return -EBADF;
+
+	entry = ring_buffer_event_data(event);
+
+	len = __copy_from_user_inatomic(&entry->id, ubuf, cnt);
+	if (len) {
+		entry->id = -1;
+		memcpy(&entry->buf, faulted, FAULTED_SIZE);
+		written = -EFAULT;
+	} else
+		written = cnt;
+
+	__buffer_unlock_commit(buffer, event);
+
+	if (written > 0)
+		*fpos += written;
+
+	return written;
+}
+
+static int tracing_clock_show(struct seq_file *m, void *v)
+{
+	struct trace_array *tr = m->private;
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(trace_clocks); i++)
+		seq_printf(m,
+			"%s%s%s%s", i ? " " : "",
+			i == tr->clock_id ? "[" : "", trace_clocks[i].name,
+			i == tr->clock_id ? "]" : "");
+	seq_putc(m, '\n');
+
+	return 0;
+}
+
+int tracing_set_clock(struct trace_array *tr, const char *clockstr)
+{
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(trace_clocks); i++) {
+		if (strcmp(trace_clocks[i].name, clockstr) == 0)
+			break;
+	}
+	if (i == ARRAY_SIZE(trace_clocks))
+		return -EINVAL;
+
+	mutex_lock(&trace_types_lock);
+
+	tr->clock_id = i;
+
+	ring_buffer_set_clock(tr->trace_buffer.buffer, trace_clocks[i].func);
+
+	/*
+	 * New clock may not be consistent with the previous clock.
+	 * Reset the buffer so that it doesn't have incomparable timestamps.
+	 */
+	tracing_reset_online_cpus(&tr->trace_buffer);
+
+#ifdef CONFIG_TRACER_MAX_TRACE
+	if (tr->max_buffer.buffer)
+		ring_buffer_set_clock(tr->max_buffer.buffer, trace_clocks[i].func);
+	tracing_reset_online_cpus(&tr->max_buffer);
+#endif
+
+	mutex_unlock(&trace_types_lock);
+
+	return 0;
+}
+
+static ssize_t tracing_clock_write(struct file *filp, const char __user *ubuf,
+				   size_t cnt, loff_t *fpos)
+{
+	struct seq_file *m = filp->private_data;
+	struct trace_array *tr = m->private;
+	char buf[64];
+	const char *clockstr;
+	int ret;
+
+	if (cnt >= sizeof(buf))
+		return -EINVAL;
+
+	if (copy_from_user(buf, ubuf, cnt))
+		return -EFAULT;
+
+	buf[cnt] = 0;
+
+	clockstr = strstrip(buf);
+
+	ret = tracing_set_clock(tr, clockstr);
+	if (ret)
+		return ret;
+
+	*fpos += cnt;
+
+	return cnt;
+}
+
+static int tracing_clock_open(struct inode *inode, struct file *file)
+{
+	struct trace_array *tr = inode->i_private;
+	int ret;
+
+	if (tracing_disabled)
+		return -ENODEV;
+
+	if (trace_array_get(tr))
+		return -ENODEV;
+
+	ret = single_open(file, tracing_clock_show, inode->i_private);
+	if (ret < 0)
+		trace_array_put(tr);
+
+	return ret;
+}
+
+static int tracing_time_stamp_mode_show(struct seq_file *m, void *v)
+{
+	struct trace_array *tr = m->private;
+
+	mutex_lock(&trace_types_lock);
+
+	if (ring_buffer_time_stamp_abs(tr->trace_buffer.buffer))
+		seq_puts(m, "delta [absolute]\n");
+	else
+		seq_puts(m, "[delta] absolute\n");
+
+	mutex_unlock(&trace_types_lock);
+
+	return 0;
+}
+
+static int tracing_time_stamp_mode_open(struct inode *inode, struct file *file)
+{
+	struct trace_array *tr = inode->i_private;
+	int ret;
+
+	if (tracing_disabled)
+		return -ENODEV;
+
+	if (trace_array_get(tr))
+		return -ENODEV;
+
+	ret = single_open(file, tracing_time_stamp_mode_show, inode->i_private);
+	if (ret < 0)
+		trace_array_put(tr);
+
+	return ret;
+}
+
+int tracing_set_time_stamp_abs(struct trace_array *tr, bool abs)
+{
+	int ret = 0;
+
+	mutex_lock(&trace_types_lock);
+
+	if (abs && tr->time_stamp_abs_ref++)
+		goto out;
+
+	if (!abs) {
+		if (WARN_ON_ONCE(!tr->time_stamp_abs_ref)) {
+			ret = -EINVAL;
+			goto out;
+		}
+
+		if (--tr->time_stamp_abs_ref)
+			goto out;
+	}
+
+	ring_buffer_set_time_stamp_abs(tr->trace_buffer.buffer, abs);
+
+#ifdef CONFIG_TRACER_MAX_TRACE
+	if (tr->max_buffer.buffer)
+		ring_buffer_set_time_stamp_abs(tr->max_buffer.buffer, abs);
+#endif
+ out:
+	mutex_unlock(&trace_types_lock);
+
+	return ret;
+}
+
+struct ftrace_buffer_info {
+	struct trace_iterator	iter;
+	void			*spare;
+	unsigned int		spare_cpu;
+	unsigned int		read;
+};
+
+#ifdef CONFIG_TRACER_SNAPSHOT
+static int tracing_snapshot_open(struct inode *inode, struct file *file)
+{
+	struct trace_array *tr = inode->i_private;
+	struct trace_iterator *iter;
+	struct seq_file *m;
+	int ret = 0;
+
+	if (trace_array_get(tr) < 0)
+		return -ENODEV;
+
+	if (file->f_mode & FMODE_READ) {
+		iter = __tracing_open(inode, file, true);
+		if (IS_ERR(iter))
+			ret = PTR_ERR(iter);
+	} else {
+		/* Writes still need the seq_file to hold the private data */
+		ret = -ENOMEM;
+		m = kzalloc(sizeof(*m), GFP_KERNEL);
+		if (!m)
+			goto out;
+		iter = kzalloc(sizeof(*iter), GFP_KERNEL);
+		if (!iter) {
+			kfree(m);
+			goto out;
+		}
+		ret = 0;
+
+		iter->tr = tr;
+		iter->trace_buffer = &tr->max_buffer;
+		iter->cpu_file = tracing_get_cpu(inode);
+		m->private = iter;
+		file->private_data = m;
+	}
+out:
+	if (ret < 0)
+		trace_array_put(tr);
+
+	return ret;
+}
+
+static ssize_t
+tracing_snapshot_write(struct file *filp, const char __user *ubuf, size_t cnt,
+		       loff_t *ppos)
+{
+	struct seq_file *m = filp->private_data;
+	struct trace_iterator *iter = m->private;
+	struct trace_array *tr = iter->tr;
+	unsigned long val;
+	int ret;
+
+	ret = tracing_update_buffers();
+	if (ret < 0)
+		return ret;
+
+	ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
+	if (ret)
+		return ret;
+
+	mutex_lock(&trace_types_lock);
+
+	if (tr->current_trace->use_max_tr) {
+		ret = -EBUSY;
+		goto out;
+	}
+
+	switch (val) {
+	case 0:
+		if (iter->cpu_file != RING_BUFFER_ALL_CPUS) {
+			ret = -EINVAL;
+			break;
+		}
+		if (tr->allocated_snapshot)
+			free_snapshot(tr);
+		break;
+	case 1:
+/* Only allow per-cpu swap if the ring buffer supports it */
+#ifndef CONFIG_RING_BUFFER_ALLOW_SWAP
+		if (iter->cpu_file != RING_BUFFER_ALL_CPUS) {
+			ret = -EINVAL;
+			break;
+		}
+#endif
+		if (tr->allocated_snapshot)
+			ret = resize_buffer_duplicate_size(&tr->max_buffer,
+					&tr->trace_buffer, iter->cpu_file);
+		else
+			ret = tracing_alloc_snapshot_instance(tr);
+		if (ret < 0)
+			break;
+		local_irq_disable();
+		/* Now, we're going to swap */
+		if (iter->cpu_file == RING_BUFFER_ALL_CPUS)
+			update_max_tr(tr, current, smp_processor_id());
+		else
+			update_max_tr_single(tr, current, iter->cpu_file);
+		local_irq_enable();
+		break;
+	default:
+		if (tr->allocated_snapshot) {
+			if (iter->cpu_file == RING_BUFFER_ALL_CPUS)
+				tracing_reset_online_cpus(&tr->max_buffer);
+			else
+				tracing_reset(&tr->max_buffer, iter->cpu_file);
+		}
+		break;
+	}
+
+	if (ret >= 0) {
+		*ppos += cnt;
+		ret = cnt;
+	}
+out:
+	mutex_unlock(&trace_types_lock);
+	return ret;
+}
+
+static int tracing_snapshot_release(struct inode *inode, struct file *file)
+{
+	struct seq_file *m = file->private_data;
+	int ret;
+
+	ret = tracing_release(inode, file);
+
+	if (file->f_mode & FMODE_READ)
+		return ret;
+
+	/* If write only, the seq_file is just a stub */
+	if (m)
+		kfree(m->private);
+	kfree(m);
+
+	return 0;
+}
+
+static int tracing_buffers_open(struct inode *inode, struct file *filp);
+static ssize_t tracing_buffers_read(struct file *filp, char __user *ubuf,
+				    size_t count, loff_t *ppos);
+static int tracing_buffers_release(struct inode *inode, struct file *file);
+static ssize_t tracing_buffers_splice_read(struct file *file, loff_t *ppos,
+		   struct pipe_inode_info *pipe, size_t len, unsigned int flags);
+
+static int snapshot_raw_open(struct inode *inode, struct file *filp)
+{
+	struct ftrace_buffer_info *info;
+	int ret;
+
+	ret = tracing_buffers_open(inode, filp);
+	if (ret < 0)
+		return ret;
+
+	info = filp->private_data;
+
+	if (info->iter.trace->use_max_tr) {
+		tracing_buffers_release(inode, filp);
+		return -EBUSY;
+	}
+
+	info->iter.snapshot = true;
+	info->iter.trace_buffer = &info->iter.tr->max_buffer;
+
+	return ret;
+}
+
+#endif /* CONFIG_TRACER_SNAPSHOT */
+
+
+static const struct file_operations tracing_thresh_fops = {
+	.open		= tracing_open_generic,
+	.read		= tracing_thresh_read,
+	.write		= tracing_thresh_write,
+	.llseek		= generic_file_llseek,
+};
+
+#if defined(CONFIG_TRACER_MAX_TRACE) || defined(CONFIG_HWLAT_TRACER)
+static const struct file_operations tracing_max_lat_fops = {
+	.open		= tracing_open_generic,
+	.read		= tracing_max_lat_read,
+	.write		= tracing_max_lat_write,
+	.llseek		= generic_file_llseek,
+};
+#endif
+
+static const struct file_operations set_tracer_fops = {
+	.open		= tracing_open_generic,
+	.read		= tracing_set_trace_read,
+	.write		= tracing_set_trace_write,
+	.llseek		= generic_file_llseek,
+};
+
+static const struct file_operations tracing_pipe_fops = {
+	.open		= tracing_open_pipe,
+	.poll		= tracing_poll_pipe,
+	.read		= tracing_read_pipe,
+	.splice_read	= tracing_splice_read_pipe,
+	.release	= tracing_release_pipe,
+	.llseek		= no_llseek,
+};
+
+static const struct file_operations tracing_entries_fops = {
+	.open		= tracing_open_generic_tr,
+	.read		= tracing_entries_read,
+	.write		= tracing_entries_write,
+	.llseek		= generic_file_llseek,
+	.release	= tracing_release_generic_tr,
+};
+
+static const struct file_operations tracing_total_entries_fops = {
+	.open		= tracing_open_generic_tr,
+	.read		= tracing_total_entries_read,
+	.llseek		= generic_file_llseek,
+	.release	= tracing_release_generic_tr,
+};
+
+static const struct file_operations tracing_free_buffer_fops = {
+	.open		= tracing_open_generic_tr,
+	.write		= tracing_free_buffer_write,
+	.release	= tracing_free_buffer_release,
+};
+
+static const struct file_operations tracing_mark_fops = {
+	.open		= tracing_open_generic_tr,
+	.write		= tracing_mark_write,
+	.llseek		= generic_file_llseek,
+	.release	= tracing_release_generic_tr,
+};
+
+static const struct file_operations tracing_mark_raw_fops = {
+	.open		= tracing_open_generic_tr,
+	.write		= tracing_mark_raw_write,
+	.llseek		= generic_file_llseek,
+	.release	= tracing_release_generic_tr,
+};
+
+static const struct file_operations trace_clock_fops = {
+	.open		= tracing_clock_open,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.release	= tracing_single_release_tr,
+	.write		= tracing_clock_write,
+};
+
+static const struct file_operations trace_time_stamp_mode_fops = {
+	.open		= tracing_time_stamp_mode_open,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.release	= tracing_single_release_tr,
+};
+
+#ifdef CONFIG_TRACER_SNAPSHOT
+static const struct file_operations snapshot_fops = {
+	.open		= tracing_snapshot_open,
+	.read		= seq_read,
+	.write		= tracing_snapshot_write,
+	.llseek		= tracing_lseek,
+	.release	= tracing_snapshot_release,
+};
+
+static const struct file_operations snapshot_raw_fops = {
+	.open		= snapshot_raw_open,
+	.read		= tracing_buffers_read,
+	.release	= tracing_buffers_release,
+	.splice_read	= tracing_buffers_splice_read,
+	.llseek		= no_llseek,
+};
+
+#endif /* CONFIG_TRACER_SNAPSHOT */
+
+static int tracing_buffers_open(struct inode *inode, struct file *filp)
+{
+	struct trace_array *tr = inode->i_private;
+	struct ftrace_buffer_info *info;
+	int ret;
+
+	if (tracing_disabled)
+		return -ENODEV;
+
+	if (trace_array_get(tr) < 0)
+		return -ENODEV;
+
+	info = kzalloc(sizeof(*info), GFP_KERNEL);
+	if (!info) {
+		trace_array_put(tr);
+		return -ENOMEM;
+	}
+
+	mutex_lock(&trace_types_lock);
+
+	info->iter.tr		= tr;
+	info->iter.cpu_file	= tracing_get_cpu(inode);
+	info->iter.trace	= tr->current_trace;
+	info->iter.trace_buffer = &tr->trace_buffer;
+	info->spare		= NULL;
+	/* Force reading ring buffer for first read */
+	info->read		= (unsigned int)-1;
+
+	filp->private_data = info;
+
+	tr->current_trace->ref++;
+
+	mutex_unlock(&trace_types_lock);
+
+	ret = nonseekable_open(inode, filp);
+	if (ret < 0)
+		trace_array_put(tr);
+
+	return ret;
+}
+
+static __poll_t
+tracing_buffers_poll(struct file *filp, poll_table *poll_table)
+{
+	struct ftrace_buffer_info *info = filp->private_data;
+	struct trace_iterator *iter = &info->iter;
+
+	return trace_poll(iter, filp, poll_table);
+}
+
+static ssize_t
+tracing_buffers_read(struct file *filp, char __user *ubuf,
+		     size_t count, loff_t *ppos)
+{
+	struct ftrace_buffer_info *info = filp->private_data;
+	struct trace_iterator *iter = &info->iter;
+	ssize_t ret = 0;
+	ssize_t size;
+
+	if (!count)
+		return 0;
+
+#ifdef CONFIG_TRACER_MAX_TRACE
+	if (iter->snapshot && iter->tr->current_trace->use_max_tr)
+		return -EBUSY;
+#endif
+
+	if (!info->spare) {
+		info->spare = ring_buffer_alloc_read_page(iter->trace_buffer->buffer,
+							  iter->cpu_file);
+		if (IS_ERR(info->spare)) {
+			ret = PTR_ERR(info->spare);
+			info->spare = NULL;
+		} else {
+			info->spare_cpu = iter->cpu_file;
+		}
+	}
+	if (!info->spare)
+		return ret;
+
+	/* Do we have previous read data to read? */
+	if (info->read < PAGE_SIZE)
+		goto read;
+
+ again:
+	trace_access_lock(iter->cpu_file);
+	ret = ring_buffer_read_page(iter->trace_buffer->buffer,
+				    &info->spare,
+				    count,
+				    iter->cpu_file, 0);
+	trace_access_unlock(iter->cpu_file);
+
+	if (ret < 0) {
+		if (trace_empty(iter)) {
+			if ((filp->f_flags & O_NONBLOCK))
+				return -EAGAIN;
+
+			ret = wait_on_pipe(iter, false);
+			if (ret)
+				return ret;
+
+			goto again;
+		}
+		return 0;
+	}
+
+	info->read = 0;
+ read:
+	size = PAGE_SIZE - info->read;
+	if (size > count)
+		size = count;
+
+	ret = copy_to_user(ubuf, info->spare + info->read, size);
+	if (ret == size)
+		return -EFAULT;
+
+	size -= ret;
+
+	*ppos += size;
+	info->read += size;
+
+	return size;
+}
+
+static int tracing_buffers_release(struct inode *inode, struct file *file)
+{
+	struct ftrace_buffer_info *info = file->private_data;
+	struct trace_iterator *iter = &info->iter;
+
+	mutex_lock(&trace_types_lock);
+
+	iter->tr->current_trace->ref--;
+
+	__trace_array_put(iter->tr);
+
+	if (info->spare)
+		ring_buffer_free_read_page(iter->trace_buffer->buffer,
+					   info->spare_cpu, info->spare);
+	kfree(info);
+
+	mutex_unlock(&trace_types_lock);
+
+	return 0;
+}
+
+struct buffer_ref {
+	struct ring_buffer	*buffer;
+	void			*page;
+	int			cpu;
+	refcount_t		refcount;
+};
+
+static void buffer_ref_release(struct buffer_ref *ref)
+{
+	if (!refcount_dec_and_test(&ref->refcount))
+		return;
+	ring_buffer_free_read_page(ref->buffer, ref->cpu, ref->page);
+	kfree(ref);
+}
+
+static void buffer_pipe_buf_release(struct pipe_inode_info *pipe,
+				    struct pipe_buffer *buf)
+{
+	struct buffer_ref *ref = (struct buffer_ref *)buf->private;
+
+	buffer_ref_release(ref);
+	buf->private = 0;
+}
+
+static bool buffer_pipe_buf_get(struct pipe_inode_info *pipe,
+				struct pipe_buffer *buf)
+{
+	struct buffer_ref *ref = (struct buffer_ref *)buf->private;
+
+	if (refcount_read(&ref->refcount) > INT_MAX/2)
+		return false;
+
+	refcount_inc(&ref->refcount);
+	return true;
+}
+
+/* Pipe buffer operations for a buffer. */
+static const struct pipe_buf_operations buffer_pipe_buf_ops = {
+	.can_merge		= 0,
+	.confirm		= generic_pipe_buf_confirm,
+	.release		= buffer_pipe_buf_release,
+	.steal			= generic_pipe_buf_nosteal,
+	.get			= buffer_pipe_buf_get,
+};
+
+/*
+ * Callback from splice_to_pipe(), if we need to release some pages
+ * at the end of the spd in case we error'ed out in filling the pipe.
+ */
+static void buffer_spd_release(struct splice_pipe_desc *spd, unsigned int i)
+{
+	struct buffer_ref *ref =
+		(struct buffer_ref *)spd->partial[i].private;
+
+	buffer_ref_release(ref);
+	spd->partial[i].private = 0;
+}
+
+static ssize_t
+tracing_buffers_splice_read(struct file *file, loff_t *ppos,
+			    struct pipe_inode_info *pipe, size_t len,
+			    unsigned int flags)
+{
+	struct ftrace_buffer_info *info = file->private_data;
+	struct trace_iterator *iter = &info->iter;
+	struct partial_page partial_def[PIPE_DEF_BUFFERS];
+	struct page *pages_def[PIPE_DEF_BUFFERS];
+	struct splice_pipe_desc spd = {
+		.pages		= pages_def,
+		.partial	= partial_def,
+		.nr_pages_max	= PIPE_DEF_BUFFERS,
+		.ops		= &buffer_pipe_buf_ops,
+		.spd_release	= buffer_spd_release,
+	};
+	struct buffer_ref *ref;
+	int entries, i;
+	ssize_t ret = 0;
+
+#ifdef CONFIG_TRACER_MAX_TRACE
+	if (iter->snapshot && iter->tr->current_trace->use_max_tr)
+		return -EBUSY;
+#endif
+
+	if (*ppos & (PAGE_SIZE - 1))
+		return -EINVAL;
+
+	if (len & (PAGE_SIZE - 1)) {
+		if (len < PAGE_SIZE)
+			return -EINVAL;
+		len &= PAGE_MASK;
+	}
+
+	if (splice_grow_spd(pipe, &spd))
+		return -ENOMEM;
+
+ again:
+	trace_access_lock(iter->cpu_file);
+	entries = ring_buffer_entries_cpu(iter->trace_buffer->buffer, iter->cpu_file);
+
+	for (i = 0; i < spd.nr_pages_max && len && entries; i++, len -= PAGE_SIZE) {
+		struct page *page;
+		int r;
+
+		ref = kzalloc(sizeof(*ref), GFP_KERNEL);
+		if (!ref) {
+			ret = -ENOMEM;
+			break;
+		}
+
+		refcount_set(&ref->refcount, 1);
+		ref->buffer = iter->trace_buffer->buffer;
+		ref->page = ring_buffer_alloc_read_page(ref->buffer, iter->cpu_file);
+		if (IS_ERR(ref->page)) {
+			ret = PTR_ERR(ref->page);
+			ref->page = NULL;
+			kfree(ref);
+			break;
+		}
+		ref->cpu = iter->cpu_file;
+
+		r = ring_buffer_read_page(ref->buffer, &ref->page,
+					  len, iter->cpu_file, 1);
+		if (r < 0) {
+			ring_buffer_free_read_page(ref->buffer, ref->cpu,
+						   ref->page);
+			kfree(ref);
+			break;
+		}
+
+		page = virt_to_page(ref->page);
+
+		spd.pages[i] = page;
+		spd.partial[i].len = PAGE_SIZE;
+		spd.partial[i].offset = 0;
+		spd.partial[i].private = (unsigned long)ref;
+		spd.nr_pages++;
+		*ppos += PAGE_SIZE;
+
+		entries = ring_buffer_entries_cpu(iter->trace_buffer->buffer, iter->cpu_file);
+	}
+
+	trace_access_unlock(iter->cpu_file);
+	spd.nr_pages = i;
+
+	/* did we read anything? */
+	if (!spd.nr_pages) {
+		if (ret)
+			goto out;
+
+		ret = -EAGAIN;
+		if ((file->f_flags & O_NONBLOCK) || (flags & SPLICE_F_NONBLOCK))
+			goto out;
+
+		ret = wait_on_pipe(iter, true);
+		if (ret)
+			goto out;
+
+		goto again;
+	}
+
+	ret = splice_to_pipe(pipe, &spd);
+out:
+	splice_shrink_spd(&spd);
+
+	return ret;
+}
+
+static const struct file_operations tracing_buffers_fops = {
+	.open		= tracing_buffers_open,
+	.read		= tracing_buffers_read,
+	.poll		= tracing_buffers_poll,
+	.release	= tracing_buffers_release,
+	.splice_read	= tracing_buffers_splice_read,
+	.llseek		= no_llseek,
+};
+
+static ssize_t
+tracing_stats_read(struct file *filp, char __user *ubuf,
+		   size_t count, loff_t *ppos)
+{
+	struct inode *inode = file_inode(filp);
+	struct trace_array *tr = inode->i_private;
+	struct trace_buffer *trace_buf = &tr->trace_buffer;
+	int cpu = tracing_get_cpu(inode);
+	struct trace_seq *s;
+	unsigned long cnt;
+	unsigned long long t;
+	unsigned long usec_rem;
+
+	s = kmalloc(sizeof(*s), GFP_KERNEL);
+	if (!s)
+		return -ENOMEM;
+
+	trace_seq_init(s);
+
+	cnt = ring_buffer_entries_cpu(trace_buf->buffer, cpu);
+	trace_seq_printf(s, "entries: %ld\n", cnt);
+
+	cnt = ring_buffer_overrun_cpu(trace_buf->buffer, cpu);
+	trace_seq_printf(s, "overrun: %ld\n", cnt);
+
+	cnt = ring_buffer_commit_overrun_cpu(trace_buf->buffer, cpu);
+	trace_seq_printf(s, "commit overrun: %ld\n", cnt);
+
+	cnt = ring_buffer_bytes_cpu(trace_buf->buffer, cpu);
+	trace_seq_printf(s, "bytes: %ld\n", cnt);
+
+	if (trace_clocks[tr->clock_id].in_ns) {
+		/* local or global for trace_clock */
+		t = ns2usecs(ring_buffer_oldest_event_ts(trace_buf->buffer, cpu));
+		usec_rem = do_div(t, USEC_PER_SEC);
+		trace_seq_printf(s, "oldest event ts: %5llu.%06lu\n",
+								t, usec_rem);
+
+		t = ns2usecs(ring_buffer_time_stamp(trace_buf->buffer, cpu));
+		usec_rem = do_div(t, USEC_PER_SEC);
+		trace_seq_printf(s, "now ts: %5llu.%06lu\n", t, usec_rem);
+	} else {
+		/* counter or tsc mode for trace_clock */
+		trace_seq_printf(s, "oldest event ts: %llu\n",
+				ring_buffer_oldest_event_ts(trace_buf->buffer, cpu));
+
+		trace_seq_printf(s, "now ts: %llu\n",
+				ring_buffer_time_stamp(trace_buf->buffer, cpu));
+	}
+
+	cnt = ring_buffer_dropped_events_cpu(trace_buf->buffer, cpu);
+	trace_seq_printf(s, "dropped events: %ld\n", cnt);
+
+	cnt = ring_buffer_read_events_cpu(trace_buf->buffer, cpu);
+	trace_seq_printf(s, "read events: %ld\n", cnt);
+
+	count = simple_read_from_buffer(ubuf, count, ppos,
+					s->buffer, trace_seq_used(s));
+
+	kfree(s);
+
+	return count;
+}
+
+static const struct file_operations tracing_stats_fops = {
+	.open		= tracing_open_generic_tr,
+	.read		= tracing_stats_read,
+	.llseek		= generic_file_llseek,
+	.release	= tracing_release_generic_tr,
+};
+
+#ifdef CONFIG_DYNAMIC_FTRACE
+
+static ssize_t
+tracing_read_dyn_info(struct file *filp, char __user *ubuf,
+		  size_t cnt, loff_t *ppos)
+{
+	unsigned long *p = filp->private_data;
+	char buf[64]; /* Not too big for a shallow stack */
+	int r;
+
+	r = scnprintf(buf, 63, "%ld", *p);
+	buf[r++] = '\n';
+
+	return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
+}
+
+static const struct file_operations tracing_dyn_info_fops = {
+	.open		= tracing_open_generic,
+	.read		= tracing_read_dyn_info,
+	.llseek		= generic_file_llseek,
+};
+#endif /* CONFIG_DYNAMIC_FTRACE */
+
+#if defined(CONFIG_TRACER_SNAPSHOT) && defined(CONFIG_DYNAMIC_FTRACE)
+static void
+ftrace_snapshot(unsigned long ip, unsigned long parent_ip,
+		struct trace_array *tr, struct ftrace_probe_ops *ops,
+		void *data)
+{
+	tracing_snapshot_instance(tr);
+}
+
+static void
+ftrace_count_snapshot(unsigned long ip, unsigned long parent_ip,
+		      struct trace_array *tr, struct ftrace_probe_ops *ops,
+		      void *data)
+{
+	struct ftrace_func_mapper *mapper = data;
+	long *count = NULL;
+
+	if (mapper)
+		count = (long *)ftrace_func_mapper_find_ip(mapper, ip);
+
+	if (count) {
+
+		if (*count <= 0)
+			return;
+
+		(*count)--;
+	}
+
+	tracing_snapshot_instance(tr);
+}
+
+static int
+ftrace_snapshot_print(struct seq_file *m, unsigned long ip,
+		      struct ftrace_probe_ops *ops, void *data)
+{
+	struct ftrace_func_mapper *mapper = data;
+	long *count = NULL;
+
+	seq_printf(m, "%ps:", (void *)ip);
+
+	seq_puts(m, "snapshot");
+
+	if (mapper)
+		count = (long *)ftrace_func_mapper_find_ip(mapper, ip);
+
+	if (count)
+		seq_printf(m, ":count=%ld\n", *count);
+	else
+		seq_puts(m, ":unlimited\n");
+
+	return 0;
+}
+
+static int
+ftrace_snapshot_init(struct ftrace_probe_ops *ops, struct trace_array *tr,
+		     unsigned long ip, void *init_data, void **data)
+{
+	struct ftrace_func_mapper *mapper = *data;
+
+	if (!mapper) {
+		mapper = allocate_ftrace_func_mapper();
+		if (!mapper)
+			return -ENOMEM;
+		*data = mapper;
+	}
+
+	return ftrace_func_mapper_add_ip(mapper, ip, init_data);
+}
+
+static void
+ftrace_snapshot_free(struct ftrace_probe_ops *ops, struct trace_array *tr,
+		     unsigned long ip, void *data)
+{
+	struct ftrace_func_mapper *mapper = data;
+
+	if (!ip) {
+		if (!mapper)
+			return;
+		free_ftrace_func_mapper(mapper, NULL);
+		return;
+	}
+
+	ftrace_func_mapper_remove_ip(mapper, ip);
+}
+
+static struct ftrace_probe_ops snapshot_probe_ops = {
+	.func			= ftrace_snapshot,
+	.print			= ftrace_snapshot_print,
+};
+
+static struct ftrace_probe_ops snapshot_count_probe_ops = {
+	.func			= ftrace_count_snapshot,
+	.print			= ftrace_snapshot_print,
+	.init			= ftrace_snapshot_init,
+	.free			= ftrace_snapshot_free,
+};
+
+static int
+ftrace_trace_snapshot_callback(struct trace_array *tr, struct ftrace_hash *hash,
+			       char *glob, char *cmd, char *param, int enable)
+{
+	struct ftrace_probe_ops *ops;
+	void *count = (void *)-1;
+	char *number;
+	int ret;
+
+	if (!tr)
+		return -ENODEV;
+
+	/* hash funcs only work with set_ftrace_filter */
+	if (!enable)
+		return -EINVAL;
+
+	ops = param ? &snapshot_count_probe_ops :  &snapshot_probe_ops;
+
+	if (glob[0] == '!')
+		return unregister_ftrace_function_probe_func(glob+1, tr, ops);
+
+	if (!param)
+		goto out_reg;
+
+	number = strsep(&param, ":");
+
+	if (!strlen(number))
+		goto out_reg;
+
+	/*
+	 * We use the callback data field (which is a pointer)
+	 * as our counter.
+	 */
+	ret = kstrtoul(number, 0, (unsigned long *)&count);
+	if (ret)
+		return ret;
+
+ out_reg:
+	ret = tracing_alloc_snapshot_instance(tr);
+	if (ret < 0)
+		goto out;
+
+	ret = register_ftrace_function_probe(glob, tr, ops, count);
+
+ out:
+	return ret < 0 ? ret : 0;
+}
+
+static struct ftrace_func_command ftrace_snapshot_cmd = {
+	.name			= "snapshot",
+	.func			= ftrace_trace_snapshot_callback,
+};
+
+static __init int register_snapshot_cmd(void)
+{
+	return register_ftrace_command(&ftrace_snapshot_cmd);
+}
+#else
+static inline __init int register_snapshot_cmd(void) { return 0; }
+#endif /* defined(CONFIG_TRACER_SNAPSHOT) && defined(CONFIG_DYNAMIC_FTRACE) */
+
+static struct dentry *tracing_get_dentry(struct trace_array *tr)
+{
+	if (WARN_ON(!tr->dir))
+		return ERR_PTR(-ENODEV);
+
+	/* Top directory uses NULL as the parent */
+	if (tr->flags & TRACE_ARRAY_FL_GLOBAL)
+		return NULL;
+
+	/* All sub buffers have a descriptor */
+	return tr->dir;
+}
+
+static struct dentry *tracing_dentry_percpu(struct trace_array *tr, int cpu)
+{
+	struct dentry *d_tracer;
+
+	if (tr->percpu_dir)
+		return tr->percpu_dir;
+
+	d_tracer = tracing_get_dentry(tr);
+	if (IS_ERR(d_tracer))
+		return NULL;
+
+	tr->percpu_dir = tracefs_create_dir("per_cpu", d_tracer);
+
+	WARN_ONCE(!tr->percpu_dir,
+		  "Could not create tracefs directory 'per_cpu/%d'\n", cpu);
+
+	return tr->percpu_dir;
+}
+
+static struct dentry *
+trace_create_cpu_file(const char *name, umode_t mode, struct dentry *parent,
+		      void *data, long cpu, const struct file_operations *fops)
+{
+	struct dentry *ret = trace_create_file(name, mode, parent, data, fops);
+
+	if (ret) /* See tracing_get_cpu() */
+		d_inode(ret)->i_cdev = (void *)(cpu + 1);
+	return ret;
+}
+
+static void
+tracing_init_tracefs_percpu(struct trace_array *tr, long cpu)
+{
+	struct dentry *d_percpu = tracing_dentry_percpu(tr, cpu);
+	struct dentry *d_cpu;
+	char cpu_dir[30]; /* 30 characters should be more than enough */
+
+	if (!d_percpu)
+		return;
+
+	snprintf(cpu_dir, 30, "cpu%ld", cpu);
+	d_cpu = tracefs_create_dir(cpu_dir, d_percpu);
+	if (!d_cpu) {
+		pr_warn("Could not create tracefs '%s' entry\n", cpu_dir);
+		return;
+	}
+
+	/* per cpu trace_pipe */
+	trace_create_cpu_file("trace_pipe", 0444, d_cpu,
+				tr, cpu, &tracing_pipe_fops);
+
+	/* per cpu trace */
+	trace_create_cpu_file("trace", 0644, d_cpu,
+				tr, cpu, &tracing_fops);
+
+	trace_create_cpu_file("trace_pipe_raw", 0444, d_cpu,
+				tr, cpu, &tracing_buffers_fops);
+
+	trace_create_cpu_file("stats", 0444, d_cpu,
+				tr, cpu, &tracing_stats_fops);
+
+	trace_create_cpu_file("buffer_size_kb", 0444, d_cpu,
+				tr, cpu, &tracing_entries_fops);
+
+#ifdef CONFIG_TRACER_SNAPSHOT
+	trace_create_cpu_file("snapshot", 0644, d_cpu,
+				tr, cpu, &snapshot_fops);
+
+	trace_create_cpu_file("snapshot_raw", 0444, d_cpu,
+				tr, cpu, &snapshot_raw_fops);
+#endif
+}
+
+#ifdef CONFIG_FTRACE_SELFTEST
+/* Let selftest have access to static functions in this file */
+#include "trace_selftest.c"
+#endif
+
+static ssize_t
+trace_options_read(struct file *filp, char __user *ubuf, size_t cnt,
+			loff_t *ppos)
+{
+	struct trace_option_dentry *topt = filp->private_data;
+	char *buf;
+
+	if (topt->flags->val & topt->opt->bit)
+		buf = "1\n";
+	else
+		buf = "0\n";
+
+	return simple_read_from_buffer(ubuf, cnt, ppos, buf, 2);
+}
+
+static ssize_t
+trace_options_write(struct file *filp, const char __user *ubuf, size_t cnt,
+			 loff_t *ppos)
+{
+	struct trace_option_dentry *topt = filp->private_data;
+	unsigned long val;
+	int ret;
+
+	ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
+	if (ret)
+		return ret;
+
+	if (val != 0 && val != 1)
+		return -EINVAL;
+
+	if (!!(topt->flags->val & topt->opt->bit) != val) {
+		mutex_lock(&trace_types_lock);
+		ret = __set_tracer_option(topt->tr, topt->flags,
+					  topt->opt, !val);
+		mutex_unlock(&trace_types_lock);
+		if (ret)
+			return ret;
+	}
+
+	*ppos += cnt;
+
+	return cnt;
+}
+
+
+static const struct file_operations trace_options_fops = {
+	.open = tracing_open_generic,
+	.read = trace_options_read,
+	.write = trace_options_write,
+	.llseek	= generic_file_llseek,
+};
+
+/*
+ * In order to pass in both the trace_array descriptor as well as the index
+ * to the flag that the trace option file represents, the trace_array
+ * has a character array of trace_flags_index[], which holds the index
+ * of the bit for the flag it represents. index[0] == 0, index[1] == 1, etc.
+ * The address of this character array is passed to the flag option file
+ * read/write callbacks.
+ *
+ * In order to extract both the index and the trace_array descriptor,
+ * get_tr_index() uses the following algorithm.
+ *
+ *   idx = *ptr;
+ *
+ * As the pointer itself contains the address of the index (remember
+ * index[1] == 1).
+ *
+ * Then to get the trace_array descriptor, by subtracting that index
+ * from the ptr, we get to the start of the index itself.
+ *
+ *   ptr - idx == &index[0]
+ *
+ * Then a simple container_of() from that pointer gets us to the
+ * trace_array descriptor.
+ */
+static void get_tr_index(void *data, struct trace_array **ptr,
+			 unsigned int *pindex)
+{
+	*pindex = *(unsigned char *)data;
+
+	*ptr = container_of(data - *pindex, struct trace_array,
+			    trace_flags_index);
+}
+
+static ssize_t
+trace_options_core_read(struct file *filp, char __user *ubuf, size_t cnt,
+			loff_t *ppos)
+{
+	void *tr_index = filp->private_data;
+	struct trace_array *tr;
+	unsigned int index;
+	char *buf;
+
+	get_tr_index(tr_index, &tr, &index);
+
+	if (tr->trace_flags & (1 << index))
+		buf = "1\n";
+	else
+		buf = "0\n";
+
+	return simple_read_from_buffer(ubuf, cnt, ppos, buf, 2);
+}
+
+static ssize_t
+trace_options_core_write(struct file *filp, const char __user *ubuf, size_t cnt,
+			 loff_t *ppos)
+{
+	void *tr_index = filp->private_data;
+	struct trace_array *tr;
+	unsigned int index;
+	unsigned long val;
+	int ret;
+
+	get_tr_index(tr_index, &tr, &index);
+
+	ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
+	if (ret)
+		return ret;
+
+	if (val != 0 && val != 1)
+		return -EINVAL;
+
+	mutex_lock(&event_mutex);
+	mutex_lock(&trace_types_lock);
+	ret = set_tracer_flag(tr, 1 << index, val);
+	mutex_unlock(&trace_types_lock);
+	mutex_unlock(&event_mutex);
+
+	if (ret < 0)
+		return ret;
+
+	*ppos += cnt;
+
+	return cnt;
+}
+
+static const struct file_operations trace_options_core_fops = {
+	.open = tracing_open_generic,
+	.read = trace_options_core_read,
+	.write = trace_options_core_write,
+	.llseek = generic_file_llseek,
+};
+
+struct dentry *trace_create_file(const char *name,
+				 umode_t mode,
+				 struct dentry *parent,
+				 void *data,
+				 const struct file_operations *fops)
+{
+	struct dentry *ret;
+
+	ret = tracefs_create_file(name, mode, parent, data, fops);
+	if (!ret)
+		pr_warn("Could not create tracefs '%s' entry\n", name);
+
+	return ret;
+}
+
+
+static struct dentry *trace_options_init_dentry(struct trace_array *tr)
+{
+	struct dentry *d_tracer;
+
+	if (tr->options)
+		return tr->options;
+
+	d_tracer = tracing_get_dentry(tr);
+	if (IS_ERR(d_tracer))
+		return NULL;
+
+	tr->options = tracefs_create_dir("options", d_tracer);
+	if (!tr->options) {
+		pr_warn("Could not create tracefs directory 'options'\n");
+		return NULL;
+	}
+
+	return tr->options;
+}
+
+static void
+create_trace_option_file(struct trace_array *tr,
+			 struct trace_option_dentry *topt,
+			 struct tracer_flags *flags,
+			 struct tracer_opt *opt)
+{
+	struct dentry *t_options;
+
+	t_options = trace_options_init_dentry(tr);
+	if (!t_options)
+		return;
+
+	topt->flags = flags;
+	topt->opt = opt;
+	topt->tr = tr;
+
+	topt->entry = trace_create_file(opt->name, 0644, t_options, topt,
+				    &trace_options_fops);
+
+}
+
+static void
+create_trace_option_files(struct trace_array *tr, struct tracer *tracer)
+{
+	struct trace_option_dentry *topts;
+	struct trace_options *tr_topts;
+	struct tracer_flags *flags;
+	struct tracer_opt *opts;
+	int cnt;
+	int i;
+
+	if (!tracer)
+		return;
+
+	flags = tracer->flags;
+
+	if (!flags || !flags->opts)
+		return;
+
+	/*
+	 * If this is an instance, only create flags for tracers
+	 * the instance may have.
+	 */
+	if (!trace_ok_for_array(tracer, tr))
+		return;
+
+	for (i = 0; i < tr->nr_topts; i++) {
+		/* Make sure there's no duplicate flags. */
+		if (WARN_ON_ONCE(tr->topts[i].tracer->flags == tracer->flags))
+			return;
+	}
+
+	opts = flags->opts;
+
+	for (cnt = 0; opts[cnt].name; cnt++)
+		;
+
+	topts = kcalloc(cnt + 1, sizeof(*topts), GFP_KERNEL);
+	if (!topts)
+		return;
+
+	tr_topts = krealloc(tr->topts, sizeof(*tr->topts) * (tr->nr_topts + 1),
+			    GFP_KERNEL);
+	if (!tr_topts) {
+		kfree(topts);
+		return;
+	}
+
+	tr->topts = tr_topts;
+	tr->topts[tr->nr_topts].tracer = tracer;
+	tr->topts[tr->nr_topts].topts = topts;
+	tr->nr_topts++;
+
+	for (cnt = 0; opts[cnt].name; cnt++) {
+		create_trace_option_file(tr, &topts[cnt], flags,
+					 &opts[cnt]);
+		WARN_ONCE(topts[cnt].entry == NULL,
+			  "Failed to create trace option: %s",
+			  opts[cnt].name);
+	}
+}
+
+static struct dentry *
+create_trace_option_core_file(struct trace_array *tr,
+			      const char *option, long index)
+{
+	struct dentry *t_options;
+
+	t_options = trace_options_init_dentry(tr);
+	if (!t_options)
+		return NULL;
+
+	return trace_create_file(option, 0644, t_options,
+				 (void *)&tr->trace_flags_index[index],
+				 &trace_options_core_fops);
+}
+
+static void create_trace_options_dir(struct trace_array *tr)
+{
+	struct dentry *t_options;
+	bool top_level = tr == &global_trace;
+	int i;
+
+	t_options = trace_options_init_dentry(tr);
+	if (!t_options)
+		return;
+
+	for (i = 0; trace_options[i]; i++) {
+		if (top_level ||
+		    !((1 << i) & TOP_LEVEL_TRACE_FLAGS))
+			create_trace_option_core_file(tr, trace_options[i], i);
+	}
+}
+
+static ssize_t
+rb_simple_read(struct file *filp, char __user *ubuf,
+	       size_t cnt, loff_t *ppos)
+{
+	struct trace_array *tr = filp->private_data;
+	char buf[64];
+	int r;
+
+	r = tracer_tracing_is_on(tr);
+	r = sprintf(buf, "%d\n", r);
+
+	return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
+}
+
+static ssize_t
+rb_simple_write(struct file *filp, const char __user *ubuf,
+		size_t cnt, loff_t *ppos)
+{
+	struct trace_array *tr = filp->private_data;
+	struct ring_buffer *buffer = tr->trace_buffer.buffer;
+	unsigned long val;
+	int ret;
+
+	ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
+	if (ret)
+		return ret;
+
+	if (buffer) {
+		mutex_lock(&trace_types_lock);
+		if (!!val == tracer_tracing_is_on(tr)) {
+			val = 0; /* do nothing */
+		} else if (val) {
+			tracer_tracing_on(tr);
+			if (tr->current_trace->start)
+				tr->current_trace->start(tr);
+		} else {
+			tracer_tracing_off(tr);
+			if (tr->current_trace->stop)
+				tr->current_trace->stop(tr);
+		}
+		mutex_unlock(&trace_types_lock);
+	}
+
+	(*ppos)++;
+
+	return cnt;
+}
+
+static const struct file_operations rb_simple_fops = {
+	.open		= tracing_open_generic_tr,
+	.read		= rb_simple_read,
+	.write		= rb_simple_write,
+	.release	= tracing_release_generic_tr,
+	.llseek		= default_llseek,
+};
+
+struct dentry *trace_instance_dir;
+
+static void
+init_tracer_tracefs(struct trace_array *tr, struct dentry *d_tracer);
+
+static int
+allocate_trace_buffer(struct trace_array *tr, struct trace_buffer *buf, int size)
+{
+	enum ring_buffer_flags rb_flags;
+
+	rb_flags = tr->trace_flags & TRACE_ITER_OVERWRITE ? RB_FL_OVERWRITE : 0;
+
+	buf->tr = tr;
+
+	buf->buffer = ring_buffer_alloc(size, rb_flags);
+	if (!buf->buffer)
+		return -ENOMEM;
+
+	buf->data = alloc_percpu(struct trace_array_cpu);
+	if (!buf->data) {
+		ring_buffer_free(buf->buffer);
+		buf->buffer = NULL;
+		return -ENOMEM;
+	}
+
+	/* Allocate the first page for all buffers */
+	set_buffer_entries(&tr->trace_buffer,
+			   ring_buffer_size(tr->trace_buffer.buffer, 0));
+
+	return 0;
+}
+
+static int allocate_trace_buffers(struct trace_array *tr, int size)
+{
+	int ret;
+
+	ret = allocate_trace_buffer(tr, &tr->trace_buffer, size);
+	if (ret)
+		return ret;
+
+#ifdef CONFIG_TRACER_MAX_TRACE
+	ret = allocate_trace_buffer(tr, &tr->max_buffer,
+				    allocate_snapshot ? size : 1);
+	if (WARN_ON(ret)) {
+		ring_buffer_free(tr->trace_buffer.buffer);
+		tr->trace_buffer.buffer = NULL;
+		free_percpu(tr->trace_buffer.data);
+		tr->trace_buffer.data = NULL;
+		return -ENOMEM;
+	}
+	tr->allocated_snapshot = allocate_snapshot;
+
+	/*
+	 * Only the top level trace array gets its snapshot allocated
+	 * from the kernel command line.
+	 */
+	allocate_snapshot = false;
+#endif
+
+	/*
+	 * Because of some magic with the way alloc_percpu() works on
+	 * x86_64, we need to synchronize the pgd of all the tables,
+	 * otherwise the trace events that happen in x86_64 page fault
+	 * handlers can't cope with accessing the chance that a
+	 * alloc_percpu()'d memory might be touched in the page fault trace
+	 * event. Oh, and we need to audit all other alloc_percpu() and vmalloc()
+	 * calls in tracing, because something might get triggered within a
+	 * page fault trace event!
+	 */
+	vmalloc_sync_mappings();
+
+	return 0;
+}
+
+static void free_trace_buffer(struct trace_buffer *buf)
+{
+	if (buf->buffer) {
+		ring_buffer_free(buf->buffer);
+		buf->buffer = NULL;
+		free_percpu(buf->data);
+		buf->data = NULL;
+	}
+}
+
+static void free_trace_buffers(struct trace_array *tr)
+{
+	if (!tr)
+		return;
+
+	free_trace_buffer(&tr->trace_buffer);
+
+#ifdef CONFIG_TRACER_MAX_TRACE
+	free_trace_buffer(&tr->max_buffer);
+#endif
+}
+
+static void init_trace_flags_index(struct trace_array *tr)
+{
+	int i;
+
+	/* Used by the trace options files */
+	for (i = 0; i < TRACE_FLAGS_MAX_SIZE; i++)
+		tr->trace_flags_index[i] = i;
+}
+
+static void __update_tracer_options(struct trace_array *tr)
+{
+	struct tracer *t;
+
+	for (t = trace_types; t; t = t->next)
+		add_tracer_options(tr, t);
+}
+
+static void update_tracer_options(struct trace_array *tr)
+{
+	mutex_lock(&trace_types_lock);
+	tracer_options_updated = true;
+	__update_tracer_options(tr);
+	mutex_unlock(&trace_types_lock);
+}
+
+static int instance_mkdir(const char *name)
+{
+	struct trace_array *tr;
+	int ret;
+
+	mutex_lock(&event_mutex);
+	mutex_lock(&trace_types_lock);
+
+	ret = -EEXIST;
+	list_for_each_entry(tr, &ftrace_trace_arrays, list) {
+		if (tr->name && strcmp(tr->name, name) == 0)
+			goto out_unlock;
+	}
+
+	ret = -ENOMEM;
+	tr = kzalloc(sizeof(*tr), GFP_KERNEL);
+	if (!tr)
+		goto out_unlock;
+
+	tr->name = kstrdup(name, GFP_KERNEL);
+	if (!tr->name)
+		goto out_free_tr;
+
+	if (!alloc_cpumask_var(&tr->tracing_cpumask, GFP_KERNEL))
+		goto out_free_tr;
+
+	tr->trace_flags = global_trace.trace_flags & ~ZEROED_TRACE_FLAGS;
+
+	cpumask_copy(tr->tracing_cpumask, cpu_all_mask);
+
+	raw_spin_lock_init(&tr->start_lock);
+
+	tr->max_lock = (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED;
+
+	tr->current_trace = &nop_trace;
+
+	INIT_LIST_HEAD(&tr->systems);
+	INIT_LIST_HEAD(&tr->events);
+	INIT_LIST_HEAD(&tr->hist_vars);
+
+	if (allocate_trace_buffers(tr, trace_buf_size) < 0)
+		goto out_free_tr;
+
+	tr->dir = tracefs_create_dir(name, trace_instance_dir);
+	if (!tr->dir)
+		goto out_free_tr;
+
+	ret = event_trace_add_tracer(tr->dir, tr);
+	if (ret) {
+		tracefs_remove_recursive(tr->dir);
+		goto out_free_tr;
+	}
+
+	ftrace_init_trace_array(tr);
+
+	init_tracer_tracefs(tr, tr->dir);
+	init_trace_flags_index(tr);
+	__update_tracer_options(tr);
+
+	list_add(&tr->list, &ftrace_trace_arrays);
+
+	mutex_unlock(&trace_types_lock);
+	mutex_unlock(&event_mutex);
+
+	return 0;
+
+ out_free_tr:
+	free_trace_buffers(tr);
+	free_cpumask_var(tr->tracing_cpumask);
+	kfree(tr->name);
+	kfree(tr);
+
+ out_unlock:
+	mutex_unlock(&trace_types_lock);
+	mutex_unlock(&event_mutex);
+
+	return ret;
+
+}
+
+static int instance_rmdir(const char *name)
+{
+	struct trace_array *tr;
+	int found = 0;
+	int ret;
+	int i;
+
+	mutex_lock(&event_mutex);
+	mutex_lock(&trace_types_lock);
+
+	ret = -ENODEV;
+	list_for_each_entry(tr, &ftrace_trace_arrays, list) {
+		if (tr->name && strcmp(tr->name, name) == 0) {
+			found = 1;
+			break;
+		}
+	}
+	if (!found)
+		goto out_unlock;
+
+	ret = -EBUSY;
+	if (tr->ref || (tr->current_trace && tr->current_trace->ref))
+		goto out_unlock;
+
+	list_del(&tr->list);
+
+	/* Disable all the flags that were enabled coming in */
+	for (i = 0; i < TRACE_FLAGS_MAX_SIZE; i++) {
+		if ((1 << i) & ZEROED_TRACE_FLAGS)
+			set_tracer_flag(tr, 1 << i, 0);
+	}
+
+	tracing_set_nop(tr);
+	clear_ftrace_function_probes(tr);
+	event_trace_del_tracer(tr);
+	ftrace_clear_pids(tr);
+	ftrace_destroy_function_files(tr);
+	tracefs_remove_recursive(tr->dir);
+	free_trace_buffers(tr);
+
+	for (i = 0; i < tr->nr_topts; i++) {
+		kfree(tr->topts[i].topts);
+	}
+	kfree(tr->topts);
+
+	free_cpumask_var(tr->tracing_cpumask);
+	kfree(tr->name);
+	kfree(tr);
+
+	ret = 0;
+
+ out_unlock:
+	mutex_unlock(&trace_types_lock);
+	mutex_unlock(&event_mutex);
+
+	return ret;
+}
+
+static __init void create_trace_instances(struct dentry *d_tracer)
+{
+	trace_instance_dir = tracefs_create_instance_dir("instances", d_tracer,
+							 instance_mkdir,
+							 instance_rmdir);
+	if (WARN_ON(!trace_instance_dir))
+		return;
+}
+
+static void
+init_tracer_tracefs(struct trace_array *tr, struct dentry *d_tracer)
+{
+	struct trace_event_file *file;
+	int cpu;
+
+	trace_create_file("available_tracers", 0444, d_tracer,
+			tr, &show_traces_fops);
+
+	trace_create_file("current_tracer", 0644, d_tracer,
+			tr, &set_tracer_fops);
+
+	trace_create_file("tracing_cpumask", 0644, d_tracer,
+			  tr, &tracing_cpumask_fops);
+
+	trace_create_file("trace_options", 0644, d_tracer,
+			  tr, &tracing_iter_fops);
+
+	trace_create_file("trace", 0644, d_tracer,
+			  tr, &tracing_fops);
+
+	trace_create_file("trace_pipe", 0444, d_tracer,
+			  tr, &tracing_pipe_fops);
+
+	trace_create_file("buffer_size_kb", 0644, d_tracer,
+			  tr, &tracing_entries_fops);
+
+	trace_create_file("buffer_total_size_kb", 0444, d_tracer,
+			  tr, &tracing_total_entries_fops);
+
+	trace_create_file("free_buffer", 0200, d_tracer,
+			  tr, &tracing_free_buffer_fops);
+
+	trace_create_file("trace_marker", 0220, d_tracer,
+			  tr, &tracing_mark_fops);
+
+	file = __find_event_file(tr, "ftrace", "print");
+	if (file && file->dir)
+		trace_create_file("trigger", 0644, file->dir, file,
+				  &event_trigger_fops);
+	tr->trace_marker_file = file;
+
+	trace_create_file("trace_marker_raw", 0220, d_tracer,
+			  tr, &tracing_mark_raw_fops);
+
+	trace_create_file("trace_clock", 0644, d_tracer, tr,
+			  &trace_clock_fops);
+
+	trace_create_file("tracing_on", 0644, d_tracer,
+			  tr, &rb_simple_fops);
+
+	trace_create_file("timestamp_mode", 0444, d_tracer, tr,
+			  &trace_time_stamp_mode_fops);
+
+	create_trace_options_dir(tr);
+
+#if defined(CONFIG_TRACER_MAX_TRACE) || defined(CONFIG_HWLAT_TRACER)
+	trace_create_file("tracing_max_latency", 0644, d_tracer,
+			&tr->max_latency, &tracing_max_lat_fops);
+#endif
+
+	if (ftrace_create_function_files(tr, d_tracer))
+		WARN(1, "Could not allocate function filter files");
+
+#ifdef CONFIG_TRACER_SNAPSHOT
+	trace_create_file("snapshot", 0644, d_tracer,
+			  tr, &snapshot_fops);
+#endif
+
+	for_each_tracing_cpu(cpu)
+		tracing_init_tracefs_percpu(tr, cpu);
+
+	ftrace_init_tracefs(tr, d_tracer);
+}
+
+static struct vfsmount *trace_automount(struct dentry *mntpt, void *ingore)
+{
+	struct vfsmount *mnt;
+	struct file_system_type *type;
+
+	/*
+	 * To maintain backward compatibility for tools that mount
+	 * debugfs to get to the tracing facility, tracefs is automatically
+	 * mounted to the debugfs/tracing directory.
+	 */
+	type = get_fs_type("tracefs");
+	if (!type)
+		return NULL;
+	mnt = vfs_submount(mntpt, type, "tracefs", NULL);
+	put_filesystem(type);
+	if (IS_ERR(mnt))
+		return NULL;
+	mntget(mnt);
+
+	return mnt;
+}
+
+/**
+ * tracing_init_dentry - initialize top level trace array
+ *
+ * This is called when creating files or directories in the tracing
+ * directory. It is called via fs_initcall() by any of the boot up code
+ * and expects to return the dentry of the top level tracing directory.
+ */
+struct dentry *tracing_init_dentry(void)
+{
+	struct trace_array *tr = &global_trace;
+
+	/* The top level trace array uses  NULL as parent */
+	if (tr->dir)
+		return NULL;
+
+	if (WARN_ON(!tracefs_initialized()) ||
+		(IS_ENABLED(CONFIG_DEBUG_FS) &&
+		 WARN_ON(!debugfs_initialized())))
+		return ERR_PTR(-ENODEV);
+
+	/*
+	 * As there may still be users that expect the tracing
+	 * files to exist in debugfs/tracing, we must automount
+	 * the tracefs file system there, so older tools still
+	 * work with the newer kerenl.
+	 */
+	tr->dir = debugfs_create_automount("tracing", NULL,
+					   trace_automount, NULL);
+	if (!tr->dir) {
+		pr_warn_once("Could not create debugfs directory 'tracing'\n");
+		return ERR_PTR(-ENOMEM);
+	}
+
+	return NULL;
+}
+
+extern struct trace_eval_map *__start_ftrace_eval_maps[];
+extern struct trace_eval_map *__stop_ftrace_eval_maps[];
+
+static void __init trace_eval_init(void)
+{
+	int len;
+
+	len = __stop_ftrace_eval_maps - __start_ftrace_eval_maps;
+	trace_insert_eval_map(NULL, __start_ftrace_eval_maps, len);
+}
+
+#ifdef CONFIG_MODULES
+static void trace_module_add_evals(struct module *mod)
+{
+	if (!mod->num_trace_evals)
+		return;
+
+	/*
+	 * Modules with bad taint do not have events created, do
+	 * not bother with enums either.
+	 */
+	if (trace_module_has_bad_taint(mod))
+		return;
+
+	trace_insert_eval_map(mod, mod->trace_evals, mod->num_trace_evals);
+}
+
+#ifdef CONFIG_TRACE_EVAL_MAP_FILE
+static void trace_module_remove_evals(struct module *mod)
+{
+	union trace_eval_map_item *map;
+	union trace_eval_map_item **last = &trace_eval_maps;
+
+	if (!mod->num_trace_evals)
+		return;
+
+	mutex_lock(&trace_eval_mutex);
+
+	map = trace_eval_maps;
+
+	while (map) {
+		if (map->head.mod == mod)
+			break;
+		map = trace_eval_jmp_to_tail(map);
+		last = &map->tail.next;
+		map = map->tail.next;
+	}
+	if (!map)
+		goto out;
+
+	*last = trace_eval_jmp_to_tail(map)->tail.next;
+	kfree(map);
+ out:
+	mutex_unlock(&trace_eval_mutex);
+}
+#else
+static inline void trace_module_remove_evals(struct module *mod) { }
+#endif /* CONFIG_TRACE_EVAL_MAP_FILE */
+
+static int trace_module_notify(struct notifier_block *self,
+			       unsigned long val, void *data)
+{
+	struct module *mod = data;
+
+	switch (val) {
+	case MODULE_STATE_COMING:
+		trace_module_add_evals(mod);
+		break;
+	case MODULE_STATE_GOING:
+		trace_module_remove_evals(mod);
+		break;
+	}
+
+	return 0;
+}
+
+static struct notifier_block trace_module_nb = {
+	.notifier_call = trace_module_notify,
+	.priority = 0,
+};
+#endif /* CONFIG_MODULES */
+
+static __init int tracer_init_tracefs(void)
+{
+	struct dentry *d_tracer;
+
+	trace_access_lock_init();
+
+	d_tracer = tracing_init_dentry();
+	if (IS_ERR(d_tracer))
+		return 0;
+
+	event_trace_init();
+
+	init_tracer_tracefs(&global_trace, d_tracer);
+	ftrace_init_tracefs_toplevel(&global_trace, d_tracer);
+
+	trace_create_file("tracing_thresh", 0644, d_tracer,
+			&global_trace, &tracing_thresh_fops);
+
+	trace_create_file("README", 0444, d_tracer,
+			NULL, &tracing_readme_fops);
+
+	trace_create_file("saved_cmdlines", 0444, d_tracer,
+			NULL, &tracing_saved_cmdlines_fops);
+
+	trace_create_file("saved_cmdlines_size", 0644, d_tracer,
+			  NULL, &tracing_saved_cmdlines_size_fops);
+
+	trace_create_file("saved_tgids", 0444, d_tracer,
+			NULL, &tracing_saved_tgids_fops);
+
+	trace_eval_init();
+
+	trace_create_eval_file(d_tracer);
+
+#ifdef CONFIG_MODULES
+	register_module_notifier(&trace_module_nb);
+#endif
+
+#ifdef CONFIG_DYNAMIC_FTRACE
+	trace_create_file("dyn_ftrace_total_info", 0444, d_tracer,
+			&ftrace_update_tot_cnt, &tracing_dyn_info_fops);
+#endif
+
+	create_trace_instances(d_tracer);
+
+	update_tracer_options(&global_trace);
+
+	return 0;
+}
+
+static int trace_panic_handler(struct notifier_block *this,
+			       unsigned long event, void *unused)
+{
+	if (ftrace_dump_on_oops)
+		ftrace_dump(ftrace_dump_on_oops);
+	return NOTIFY_OK;
+}
+
+static struct notifier_block trace_panic_notifier = {
+	.notifier_call  = trace_panic_handler,
+	.next           = NULL,
+	.priority       = 150   /* priority: INT_MAX >= x >= 0 */
+};
+
+static int trace_die_handler(struct notifier_block *self,
+			     unsigned long val,
+			     void *data)
+{
+	switch (val) {
+	case DIE_OOPS:
+		if (ftrace_dump_on_oops)
+			ftrace_dump(ftrace_dump_on_oops);
+		break;
+	default:
+		break;
+	}
+	return NOTIFY_OK;
+}
+
+static struct notifier_block trace_die_notifier = {
+	.notifier_call = trace_die_handler,
+	.priority = 200
+};
+
+/*
+ * printk is set to max of 1024, we really don't need it that big.
+ * Nothing should be printing 1000 characters anyway.
+ */
+#define TRACE_MAX_PRINT		1000
+
+/*
+ * Define here KERN_TRACE so that we have one place to modify
+ * it if we decide to change what log level the ftrace dump
+ * should be at.
+ */
+#define KERN_TRACE		KERN_EMERG
+
+void
+trace_printk_seq(struct trace_seq *s)
+{
+	/* Probably should print a warning here. */
+	if (s->seq.len >= TRACE_MAX_PRINT)
+		s->seq.len = TRACE_MAX_PRINT;
+
+	/*
+	 * More paranoid code. Although the buffer size is set to
+	 * PAGE_SIZE, and TRACE_MAX_PRINT is 1000, this is just
+	 * an extra layer of protection.
+	 */
+	if (WARN_ON_ONCE(s->seq.len >= s->seq.size))
+		s->seq.len = s->seq.size - 1;
+
+	/* should be zero ended, but we are paranoid. */
+	s->buffer[s->seq.len] = 0;
+
+	printk(KERN_TRACE "%s", s->buffer);
+
+	trace_seq_init(s);
+}
+
+void trace_init_global_iter(struct trace_iterator *iter)
+{
+	iter->tr = &global_trace;
+	iter->trace = iter->tr->current_trace;
+	iter->cpu_file = RING_BUFFER_ALL_CPUS;
+	iter->trace_buffer = &global_trace.trace_buffer;
+
+	if (iter->trace && iter->trace->open)
+		iter->trace->open(iter);
+
+	/* Annotate start of buffers if we had overruns */
+	if (ring_buffer_overruns(iter->trace_buffer->buffer))
+		iter->iter_flags |= TRACE_FILE_ANNOTATE;
+
+	/* Output in nanoseconds only if we are using a clock in nanoseconds. */
+	if (trace_clocks[iter->tr->clock_id].in_ns)
+		iter->iter_flags |= TRACE_FILE_TIME_IN_NS;
+}
+
+void ftrace_dump(enum ftrace_dump_mode oops_dump_mode)
+{
+	/* use static because iter can be a bit big for the stack */
+	static struct trace_iterator iter;
+	static atomic_t dump_running;
+	struct trace_array *tr = &global_trace;
+	unsigned int old_userobj;
+	unsigned long flags;
+	int cnt = 0, cpu;
+
+	/* Only allow one dump user at a time. */
+	if (atomic_inc_return(&dump_running) != 1) {
+		atomic_dec(&dump_running);
+		return;
+	}
+
+	/*
+	 * Always turn off tracing when we dump.
+	 * We don't need to show trace output of what happens
+	 * between multiple crashes.
+	 *
+	 * If the user does a sysrq-z, then they can re-enable
+	 * tracing with echo 1 > tracing_on.
+	 */
+	tracing_off();
+
+	local_irq_save(flags);
+	printk_nmi_direct_enter();
+
+	/* Simulate the iterator */
+	trace_init_global_iter(&iter);
+
+	for_each_tracing_cpu(cpu) {
+		atomic_inc(&per_cpu_ptr(iter.trace_buffer->data, cpu)->disabled);
+	}
+
+	old_userobj = tr->trace_flags & TRACE_ITER_SYM_USEROBJ;
+
+	/* don't look at user memory in panic mode */
+	tr->trace_flags &= ~TRACE_ITER_SYM_USEROBJ;
+
+	switch (oops_dump_mode) {
+	case DUMP_ALL:
+		iter.cpu_file = RING_BUFFER_ALL_CPUS;
+		break;
+	case DUMP_ORIG:
+		iter.cpu_file = raw_smp_processor_id();
+		break;
+	case DUMP_NONE:
+		goto out_enable;
+	default:
+		printk(KERN_TRACE "Bad dumping mode, switching to all CPUs dump\n");
+		iter.cpu_file = RING_BUFFER_ALL_CPUS;
+	}
+
+	printk(KERN_TRACE "Dumping ftrace buffer:\n");
+
+	/* Did function tracer already get disabled? */
+	if (ftrace_is_dead()) {
+		printk("# WARNING: FUNCTION TRACING IS CORRUPTED\n");
+		printk("#          MAY BE MISSING FUNCTION EVENTS\n");
+	}
+
+	/*
+	 * We need to stop all tracing on all CPUS to read the
+	 * the next buffer. This is a bit expensive, but is
+	 * not done often. We fill all what we can read,
+	 * and then release the locks again.
+	 */
+
+	while (!trace_empty(&iter)) {
+
+		if (!cnt)
+			printk(KERN_TRACE "---------------------------------\n");
+
+		cnt++;
+
+		trace_iterator_reset(&iter);
+		iter.iter_flags |= TRACE_FILE_LAT_FMT;
+
+		if (trace_find_next_entry_inc(&iter) != NULL) {
+			int ret;
+
+			ret = print_trace_line(&iter);
+			if (ret != TRACE_TYPE_NO_CONSUME)
+				trace_consume(&iter);
+		}
+		touch_nmi_watchdog();
+
+		trace_printk_seq(&iter.seq);
+	}
+
+	if (!cnt)
+		printk(KERN_TRACE "   (ftrace buffer empty)\n");
+	else
+		printk(KERN_TRACE "---------------------------------\n");
+
+ out_enable:
+	tr->trace_flags |= old_userobj;
+
+	for_each_tracing_cpu(cpu) {
+		atomic_dec(&per_cpu_ptr(iter.trace_buffer->data, cpu)->disabled);
+	}
+	atomic_dec(&dump_running);
+	printk_nmi_direct_exit();
+	local_irq_restore(flags);
+}
+EXPORT_SYMBOL_GPL(ftrace_dump);
+
+int trace_run_command(const char *buf, int (*createfn)(int, char **))
+{
+	char **argv;
+	int argc, ret;
+
+	argc = 0;
+	ret = 0;
+	argv = argv_split(GFP_KERNEL, buf, &argc);
+	if (!argv)
+		return -ENOMEM;
+
+	if (argc)
+		ret = createfn(argc, argv);
+
+	argv_free(argv);
+
+	return ret;
+}
+
+#define WRITE_BUFSIZE  4096
+
+ssize_t trace_parse_run_command(struct file *file, const char __user *buffer,
+				size_t count, loff_t *ppos,
+				int (*createfn)(int, char **))
+{
+	char *kbuf, *buf, *tmp;
+	int ret = 0;
+	size_t done = 0;
+	size_t size;
+
+	kbuf = kmalloc(WRITE_BUFSIZE, GFP_KERNEL);
+	if (!kbuf)
+		return -ENOMEM;
+
+	while (done < count) {
+		size = count - done;
+
+		if (size >= WRITE_BUFSIZE)
+			size = WRITE_BUFSIZE - 1;
+
+		if (copy_from_user(kbuf, buffer + done, size)) {
+			ret = -EFAULT;
+			goto out;
+		}
+		kbuf[size] = '\0';
+		buf = kbuf;
+		do {
+			tmp = strchr(buf, '\n');
+			if (tmp) {
+				*tmp = '\0';
+				size = tmp - buf + 1;
+			} else {
+				size = strlen(buf);
+				if (done + size < count) {
+					if (buf != kbuf)
+						break;
+					/* This can accept WRITE_BUFSIZE - 2 ('\n' + '\0') */
+					pr_warn("Line length is too long: Should be less than %d\n",
+						WRITE_BUFSIZE - 2);
+					ret = -EINVAL;
+					goto out;
+				}
+			}
+			done += size;
+
+			/* Remove comments */
+			tmp = strchr(buf, '#');
+
+			if (tmp)
+				*tmp = '\0';
+
+			ret = trace_run_command(buf, createfn);
+			if (ret)
+				goto out;
+			buf += size;
+
+		} while (done < count);
+	}
+	ret = done;
+
+out:
+	kfree(kbuf);
+
+	return ret;
+}
+
+__init static int tracer_alloc_buffers(void)
+{
+	int ring_buf_size;
+	int ret = -ENOMEM;
+
+	/*
+	 * Make sure we don't accidently add more trace options
+	 * than we have bits for.
+	 */
+	BUILD_BUG_ON(TRACE_ITER_LAST_BIT > TRACE_FLAGS_MAX_SIZE);
+
+	if (!alloc_cpumask_var(&tracing_buffer_mask, GFP_KERNEL))
+		goto out;
+
+	if (!alloc_cpumask_var(&global_trace.tracing_cpumask, GFP_KERNEL))
+		goto out_free_buffer_mask;
+
+	/* Only allocate trace_printk buffers if a trace_printk exists */
+	if (&__stop___trace_bprintk_fmt != &__start___trace_bprintk_fmt)
+		/* Must be called before global_trace.buffer is allocated */
+		trace_printk_init_buffers();
+
+	/* To save memory, keep the ring buffer size to its minimum */
+	if (ring_buffer_expanded)
+		ring_buf_size = trace_buf_size;
+	else
+		ring_buf_size = 1;
+
+	cpumask_copy(tracing_buffer_mask, cpu_possible_mask);
+	cpumask_copy(global_trace.tracing_cpumask, cpu_all_mask);
+
+	raw_spin_lock_init(&global_trace.start_lock);
+
+	/*
+	 * The prepare callbacks allocates some memory for the ring buffer. We
+	 * don't free the buffer if the if the CPU goes down. If we were to free
+	 * the buffer, then the user would lose any trace that was in the
+	 * buffer. The memory will be removed once the "instance" is removed.
+	 */
+	ret = cpuhp_setup_state_multi(CPUHP_TRACE_RB_PREPARE,
+				      "trace/RB:preapre", trace_rb_cpu_prepare,
+				      NULL);
+	if (ret < 0)
+		goto out_free_cpumask;
+	/* Used for event triggers */
+	ret = -ENOMEM;
+	temp_buffer = ring_buffer_alloc(PAGE_SIZE, RB_FL_OVERWRITE);
+	if (!temp_buffer)
+		goto out_rm_hp_state;
+
+	if (trace_create_savedcmd() < 0)
+		goto out_free_temp_buffer;
+
+	/* TODO: make the number of buffers hot pluggable with CPUS */
+	if (allocate_trace_buffers(&global_trace, ring_buf_size) < 0) {
+		printk(KERN_ERR "tracer: failed to allocate ring buffer!\n");
+		WARN_ON(1);
+		goto out_free_savedcmd;
+	}
+
+	if (global_trace.buffer_disabled)
+		tracing_off();
+
+	if (trace_boot_clock) {
+		ret = tracing_set_clock(&global_trace, trace_boot_clock);
+		if (ret < 0)
+			pr_warn("Trace clock %s not defined, going back to default\n",
+				trace_boot_clock);
+	}
+
+	/*
+	 * register_tracer() might reference current_trace, so it
+	 * needs to be set before we register anything. This is
+	 * just a bootstrap of current_trace anyway.
+	 */
+	global_trace.current_trace = &nop_trace;
+
+	global_trace.max_lock = (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED;
+
+	ftrace_init_global_array_ops(&global_trace);
+
+	init_trace_flags_index(&global_trace);
+
+	register_tracer(&nop_trace);
+
+	/* Function tracing may start here (via kernel command line) */
+	init_function_trace();
+
+	/* All seems OK, enable tracing */
+	tracing_disabled = 0;
+
+	atomic_notifier_chain_register(&panic_notifier_list,
+				       &trace_panic_notifier);
+
+	register_die_notifier(&trace_die_notifier);
+
+	global_trace.flags = TRACE_ARRAY_FL_GLOBAL;
+
+	INIT_LIST_HEAD(&global_trace.systems);
+	INIT_LIST_HEAD(&global_trace.events);
+	INIT_LIST_HEAD(&global_trace.hist_vars);
+	list_add(&global_trace.list, &ftrace_trace_arrays);
+
+	apply_trace_boot_options();
+
+	register_snapshot_cmd();
+
+	return 0;
+
+out_free_savedcmd:
+	free_saved_cmdlines_buffer(savedcmd);
+out_free_temp_buffer:
+	ring_buffer_free(temp_buffer);
+out_rm_hp_state:
+	cpuhp_remove_multi_state(CPUHP_TRACE_RB_PREPARE);
+out_free_cpumask:
+	free_cpumask_var(global_trace.tracing_cpumask);
+out_free_buffer_mask:
+	free_cpumask_var(tracing_buffer_mask);
+out:
+	return ret;
+}
+
+void __init early_trace_init(void)
+{
+	if (tracepoint_printk) {
+		tracepoint_print_iter =
+			kmalloc(sizeof(*tracepoint_print_iter), GFP_KERNEL);
+		if (WARN_ON(!tracepoint_print_iter))
+			tracepoint_printk = 0;
+		else
+			static_key_enable(&tracepoint_printk_key.key);
+	}
+	tracer_alloc_buffers();
+}
+
+void __init trace_init(void)
+{
+	trace_event_init();
+}
+
+__init static int clear_boot_tracer(void)
+{
+	/*
+	 * The default tracer at boot buffer is an init section.
+	 * This function is called in lateinit. If we did not
+	 * find the boot tracer, then clear it out, to prevent
+	 * later registration from accessing the buffer that is
+	 * about to be freed.
+	 */
+	if (!default_bootup_tracer)
+		return 0;
+
+	printk(KERN_INFO "ftrace bootup tracer '%s' not registered.\n",
+	       default_bootup_tracer);
+	default_bootup_tracer = NULL;
+
+	return 0;
+}
+
+fs_initcall(tracer_init_tracefs);
+late_initcall_sync(clear_boot_tracer);
+
+#ifdef CONFIG_HAVE_UNSTABLE_SCHED_CLOCK
+__init static int tracing_set_default_clock(void)
+{
+	/* sched_clock_stable() is determined in late_initcall */
+	if (!trace_boot_clock && !sched_clock_stable()) {
+		printk(KERN_WARNING
+		       "Unstable clock detected, switching default tracing clock to \"global\"\n"
+		       "If you want to keep using the local clock, then add:\n"
+		       "  \"trace_clock=local\"\n"
+		       "on the kernel command line\n");
+		tracing_set_clock(&global_trace, "global");
+	}
+
+	return 0;
+}
+late_initcall_sync(tracing_set_default_clock);
+#endif