Merge branch 'master' of master.kernel.org:/pub/scm/linux/kernel/git/torvalds/linux-2.6

Conflicts:

	Documentation/powerpc/booting-without-of.txt
	drivers/atm/Makefile
	drivers/net/fs_enet/fs_enet-main.c
	drivers/pci/pci-acpi.c
	net/8021q/vlan.c
	net/iucv/iucv.c

1 files changed, 3161 insertions, 0 deletions

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
new file mode 100644
index 000000000000..868e121c8e38
--- /dev/null
+++ b/kernel/trace/trace.c
@@ -0,0 +1,3161 @@
+/*
+ * ring buffer based function tracer
+ *
+ * Copyright (C) 2007-2008 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 William Lee Irwin III
+ */
+#include <linux/utsrelease.h>
+#include <linux/kallsyms.h>
+#include <linux/seq_file.h>
+#include <linux/debugfs.h>
+#include <linux/pagemap.h>
+#include <linux/hardirq.h>
+#include <linux/linkage.h>
+#include <linux/uaccess.h>
+#include <linux/ftrace.h>
+#include <linux/module.h>
+#include <linux/percpu.h>
+#include <linux/ctype.h>
+#include <linux/init.h>
+#include <linux/poll.h>
+#include <linux/gfp.h>
+#include <linux/fs.h>
+#include <linux/kprobes.h>
+#include <linux/writeback.h>
+
+#include <linux/stacktrace.h>
+
+#include "trace.h"
+
+unsigned long __read_mostly	tracing_max_latency = (cycle_t)ULONG_MAX;
+unsigned long __read_mostly	tracing_thresh;
+
+static unsigned long __read_mostly	tracing_nr_buffers;
+static cpumask_t __read_mostly		tracing_buffer_mask;
+
+#define for_each_tracing_cpu(cpu)	\
+	for_each_cpu_mask(cpu, tracing_buffer_mask)
+
+static int trace_alloc_page(void);
+static int trace_free_page(void);
+
+static int tracing_disabled = 1;
+
+static unsigned long tracing_pages_allocated;
+
+long
+ns2usecs(cycle_t nsec)
+{
+	nsec += 500;
+	do_div(nsec, 1000);
+	return nsec;
+}
+
+cycle_t ftrace_now(int cpu)
+{
+	return cpu_clock(cpu);
+}
+
+/*
+ * The global_trace is the descriptor that holds the tracing
+ * buffers for the live tracing. For each CPU, it contains
+ * a link list of pages that will store trace entries. The
+ * page descriptor of the pages in the memory is used to hold
+ * the link list by linking the lru item in the page descriptor
+ * to each of the pages in the buffer per CPU.
+ *
+ * For each active CPU there is a data field that holds the
+ * pages for the buffer for that CPU. Each CPU has the same number
+ * of pages allocated for its buffer.
+ */
+static struct trace_array	global_trace;
+
+static DEFINE_PER_CPU(struct trace_array_cpu, global_trace_cpu);
+
+/*
+ * The max_tr is used to snapshot the global_trace when a maximum
+ * latency is reached. Some tracers will use this to store a maximum
+ * trace while it continues examining live traces.
+ *
+ * The buffers for the max_tr are set up the same as the global_trace.
+ * When a snapshot is taken, the link list of the max_tr is swapped
+ * with the link list of the global_trace and the buffers are reset for
+ * the global_trace so the tracing can continue.
+ */
+static struct trace_array	max_tr;
+
+static DEFINE_PER_CPU(struct trace_array_cpu, max_data);
+
+/* tracer_enabled is used to toggle activation of a tracer */
+static int			tracer_enabled = 1;
+
+/* function tracing enabled */
+int				ftrace_function_enabled;
+
+/*
+ * trace_nr_entries is the number of entries that is allocated
+ * for a buffer. Note, the number of entries is always rounded
+ * to ENTRIES_PER_PAGE.
+ */
+static unsigned long		trace_nr_entries = 65536UL;
+
+/* trace_types holds a link list of available tracers. */
+static struct tracer		*trace_types __read_mostly;
+
+/* current_trace points to the tracer that is currently active */
+static struct tracer		*current_trace __read_mostly;
+
+/*
+ * max_tracer_type_len is used to simplify the allocating of
+ * buffers to read userspace tracer names. We keep track of
+ * the longest tracer name registered.
+ */
+static int			max_tracer_type_len;
+
+/*
+ * trace_types_lock is used to protect the trace_types list.
+ * This lock is also used to keep user access serialized.
+ * Accesses from userspace will grab this lock while userspace
+ * activities happen inside the kernel.
+ */
+static DEFINE_MUTEX(trace_types_lock);
+
+/* trace_wait is a waitqueue for tasks blocked on trace_poll */
+static DECLARE_WAIT_QUEUE_HEAD(trace_wait);
+
+/* trace_flags holds iter_ctrl options */
+unsigned long trace_flags = TRACE_ITER_PRINT_PARENT;
+
+static notrace void no_trace_init(struct trace_array *tr)
+{
+	int cpu;
+
+	ftrace_function_enabled = 0;
+	if(tr->ctrl)
+		for_each_online_cpu(cpu)
+			tracing_reset(tr->data[cpu]);
+	tracer_enabled = 0;
+}
+
+/* dummy trace to disable tracing */
+static struct tracer no_tracer __read_mostly = {
+	.name		= "none",
+	.init		= no_trace_init
+};
+
+
+/**
+ * trace_wake_up - wake up tasks waiting for trace input
+ *
+ * Simply wakes up any task that is blocked on the trace_wait
+ * queue. These is used with trace_poll for tasks polling the trace.
+ */
+void trace_wake_up(void)
+{
+	/*
+	 * The runqueue_is_locked() can fail, but this is the best we
+	 * have for now:
+	 */
+	if (!(trace_flags & TRACE_ITER_BLOCK) && !runqueue_is_locked())
+		wake_up(&trace_wait);
+}
+
+#define ENTRIES_PER_PAGE (PAGE_SIZE / sizeof(struct trace_entry))
+
+static int __init set_nr_entries(char *str)
+{
+	unsigned long nr_entries;
+	int ret;
+
+	if (!str)
+		return 0;
+	ret = strict_strtoul(str, 0, &nr_entries);
+	/* nr_entries can not be zero */
+	if (ret < 0 || nr_entries == 0)
+		return 0;
+	trace_nr_entries = nr_entries;
+	return 1;
+}
+__setup("trace_entries=", set_nr_entries);
+
+unsigned long nsecs_to_usecs(unsigned long nsecs)
+{
+	return nsecs / 1000;
+}
+
+/*
+ * trace_flag_type is an enumeration that holds different
+ * states when a trace occurs. These are:
+ *  IRQS_OFF	- interrupts were disabled
+ *  NEED_RESCED - reschedule is requested
+ *  HARDIRQ	- inside an interrupt handler
+ *  SOFTIRQ	- inside a softirq handler
+ */
+enum trace_flag_type {
+	TRACE_FLAG_IRQS_OFF		= 0x01,
+	TRACE_FLAG_NEED_RESCHED		= 0x02,
+	TRACE_FLAG_HARDIRQ		= 0x04,
+	TRACE_FLAG_SOFTIRQ		= 0x08,
+};
+
+/*
+ * TRACE_ITER_SYM_MASK masks the options in trace_flags that
+ * control the output of kernel symbols.
+ */
+#define TRACE_ITER_SYM_MASK \
+	(TRACE_ITER_PRINT_PARENT|TRACE_ITER_SYM_OFFSET|TRACE_ITER_SYM_ADDR)
+
+/* These must match the bit postions in trace_iterator_flags */
+static const char *trace_options[] = {
+	"print-parent",
+	"sym-offset",
+	"sym-addr",
+	"verbose",
+	"raw",
+	"hex",
+	"bin",
+	"block",
+	"stacktrace",
+	"sched-tree",
+	NULL
+};
+
+/*
+ * ftrace_max_lock is used to protect the swapping of buffers
+ * when taking a max snapshot. The buffers themselves are
+ * protected by per_cpu spinlocks. But the action of the swap
+ * needs its own lock.
+ *
+ * This is defined as a raw_spinlock_t in order to help
+ * with performance when lockdep debugging is enabled.
+ */
+static raw_spinlock_t ftrace_max_lock =
+	(raw_spinlock_t)__RAW_SPIN_LOCK_UNLOCKED;
+
+/*
+ * Copy the new maximum trace into the separate maximum-trace
+ * structure. (this way the maximum trace is permanently saved,
+ * for later retrieval via /debugfs/tracing/latency_trace)
+ */
+static void
+__update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu)
+{
+	struct trace_array_cpu *data = tr->data[cpu];
+
+	max_tr.cpu = cpu;
+	max_tr.time_start = data->preempt_timestamp;
+
+	data = max_tr.data[cpu];
+	data->saved_latency = tracing_max_latency;
+
+	memcpy(data->comm, tsk->comm, TASK_COMM_LEN);
+	data->pid = tsk->pid;
+	data->uid = tsk->uid;
+	data->nice = tsk->static_prio - 20 - MAX_RT_PRIO;
+	data->policy = tsk->policy;
+	data->rt_priority = tsk->rt_priority;
+
+	/* record this tasks comm */
+	tracing_record_cmdline(current);
+}
+
+#define CHECK_COND(cond)			\
+	if (unlikely(cond)) {			\
+		tracing_disabled = 1;		\
+		WARN_ON(1);			\
+		return -1;			\
+	}
+
+/**
+ * check_pages - integrity check of trace buffers
+ *
+ * As a safty measure we check to make sure the data pages have not
+ * been corrupted.
+ */
+int check_pages(struct trace_array_cpu *data)
+{
+	struct page *page, *tmp;
+
+	CHECK_COND(data->trace_pages.next->prev != &data->trace_pages);
+	CHECK_COND(data->trace_pages.prev->next != &data->trace_pages);
+
+	list_for_each_entry_safe(page, tmp, &data->trace_pages, lru) {
+		CHECK_COND(page->lru.next->prev != &page->lru);
+		CHECK_COND(page->lru.prev->next != &page->lru);
+	}
+
+	return 0;
+}
+
+/**
+ * head_page - page address of the first page in per_cpu buffer.
+ *
+ * head_page returns the page address of the first page in
+ * a per_cpu buffer. This also preforms various consistency
+ * checks to make sure the buffer has not been corrupted.
+ */
+void *head_page(struct trace_array_cpu *data)
+{
+	struct page *page;
+
+	if (list_empty(&data->trace_pages))
+		return NULL;
+
+	page = list_entry(data->trace_pages.next, struct page, lru);
+	BUG_ON(&page->lru == &data->trace_pages);
+
+	return page_address(page);
+}
+
+/**
+ * trace_seq_printf - sequence printing of trace information
+ * @s: trace sequence descriptor
+ * @fmt: printf format string
+ *
+ * The tracer may use either sequence operations or its own
+ * copy to user routines. To simplify formating of a trace
+ * trace_seq_printf is used to store strings into a special
+ * buffer (@s). Then the output may be either used by
+ * the sequencer or pulled into another buffer.
+ */
+int
+trace_seq_printf(struct trace_seq *s, const char *fmt, ...)
+{
+	int len = (PAGE_SIZE - 1) - s->len;
+	va_list ap;
+	int ret;
+
+	if (!len)
+		return 0;
+
+	va_start(ap, fmt);
+	ret = vsnprintf(s->buffer + s->len, len, fmt, ap);
+	va_end(ap);
+
+	/* If we can't write it all, don't bother writing anything */
+	if (ret >= len)
+		return 0;
+
+	s->len += ret;
+
+	return len;
+}
+
+/**
+ * trace_seq_puts - trace sequence printing of simple string
+ * @s: trace sequence descriptor
+ * @str: simple string to record
+ *
+ * The tracer may use either the sequence operations or its own
+ * copy to user routines. This function records a simple string
+ * into a special buffer (@s) for later retrieval by a sequencer
+ * or other mechanism.
+ */
+static int
+trace_seq_puts(struct trace_seq *s, const char *str)
+{
+	int len = strlen(str);
+
+	if (len > ((PAGE_SIZE - 1) - s->len))
+		return 0;
+
+	memcpy(s->buffer + s->len, str, len);
+	s->len += len;
+
+	return len;
+}
+
+static int
+trace_seq_putc(struct trace_seq *s, unsigned char c)
+{
+	if (s->len >= (PAGE_SIZE - 1))
+		return 0;
+
+	s->buffer[s->len++] = c;
+
+	return 1;
+}
+
+static int
+trace_seq_putmem(struct trace_seq *s, void *mem, size_t len)
+{
+	if (len > ((PAGE_SIZE - 1) - s->len))
+		return 0;
+
+	memcpy(s->buffer + s->len, mem, len);
+	s->len += len;
+
+	return len;
+}
+
+#define HEX_CHARS 17
+static const char hex2asc[] = "0123456789abcdef";
+
+static int
+trace_seq_putmem_hex(struct trace_seq *s, void *mem, size_t len)
+{
+	unsigned char hex[HEX_CHARS];
+	unsigned char *data = mem;
+	unsigned char byte;
+	int i, j;
+
+	BUG_ON(len >= HEX_CHARS);
+
+#ifdef __BIG_ENDIAN
+	for (i = 0, j = 0; i < len; i++) {
+#else
+	for (i = len-1, j = 0; i >= 0; i--) {
+#endif
+		byte = data[i];
+
+		hex[j++] = hex2asc[byte & 0x0f];
+		hex[j++] = hex2asc[byte >> 4];
+	}
+	hex[j++] = ' ';
+
+	return trace_seq_putmem(s, hex, j);
+}
+
+static void
+trace_seq_reset(struct trace_seq *s)
+{
+	s->len = 0;
+	s->readpos = 0;
+}
+
+ssize_t trace_seq_to_user(struct trace_seq *s, char __user *ubuf, size_t cnt)
+{
+	int len;
+	int ret;
+
+	if (s->len <= s->readpos)
+		return -EBUSY;
+
+	len = s->len - s->readpos;
+	if (cnt > len)
+		cnt = len;
+	ret = copy_to_user(ubuf, s->buffer + s->readpos, cnt);
+	if (ret)
+		return -EFAULT;
+
+	s->readpos += len;
+	return cnt;
+}
+
+static void
+trace_print_seq(struct seq_file *m, struct trace_seq *s)
+{
+	int len = s->len >= PAGE_SIZE ? PAGE_SIZE - 1 : s->len;
+
+	s->buffer[len] = 0;
+	seq_puts(m, s->buffer);
+
+	trace_seq_reset(s);
+}
+
+/*
+ * flip the trace buffers between two trace descriptors.
+ * This usually is the buffers between the global_trace and
+ * the max_tr to record a snapshot of a current trace.
+ *
+ * The ftrace_max_lock must be held.
+ */
+static void
+flip_trace(struct trace_array_cpu *tr1, struct trace_array_cpu *tr2)
+{
+	struct list_head flip_pages;
+
+	INIT_LIST_HEAD(&flip_pages);
+
+	memcpy(&tr1->trace_head_idx, &tr2->trace_head_idx,
+		sizeof(struct trace_array_cpu) -
+		offsetof(struct trace_array_cpu, trace_head_idx));
+
+	check_pages(tr1);
+	check_pages(tr2);
+	list_splice_init(&tr1->trace_pages, &flip_pages);
+	list_splice_init(&tr2->trace_pages, &tr1->trace_pages);
+	list_splice_init(&flip_pages, &tr2->trace_pages);
+	BUG_ON(!list_empty(&flip_pages));
+	check_pages(tr1);
+	check_pages(tr2);
+}
+
+/**
+ * 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)
+{
+	struct trace_array_cpu *data;
+	int i;
+
+	WARN_ON_ONCE(!irqs_disabled());
+	__raw_spin_lock(&ftrace_max_lock);
+	/* clear out all the previous traces */
+	for_each_tracing_cpu(i) {
+		data = tr->data[i];
+		flip_trace(max_tr.data[i], data);
+		tracing_reset(data);
+	}
+
+	__update_max_tr(tr, tsk, cpu);
+	__raw_spin_unlock(&ftrace_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)
+{
+	struct trace_array_cpu *data = tr->data[cpu];
+	int i;
+
+	WARN_ON_ONCE(!irqs_disabled());
+	__raw_spin_lock(&ftrace_max_lock);
+	for_each_tracing_cpu(i)
+		tracing_reset(max_tr.data[i]);
+
+	flip_trace(max_tr.data[cpu], data);
+	tracing_reset(data);
+
+	__update_max_tr(tr, tsk, cpu);
+	__raw_spin_unlock(&ftrace_max_lock);
+}
+
+/**
+ * register_tracer - register a tracer with the ftrace system.
+ * @type - the plugin for the tracer
+ *
+ * Register a new plugin tracer.
+ */
+int register_tracer(struct tracer *type)
+{
+	struct tracer *t;
+	int len;
+	int ret = 0;
+
+	if (!type->name) {
+		pr_info("Tracer must have a name\n");
+		return -1;
+	}
+
+	mutex_lock(&trace_types_lock);
+	for (t = trace_types; t; t = t->next) {
+		if (strcmp(type->name, t->name) == 0) {
+			/* already found */
+			pr_info("Trace %s already registered\n",
+				type->name);
+			ret = -1;
+			goto out;
+		}
+	}
+
+#ifdef CONFIG_FTRACE_STARTUP_TEST
+	if (type->selftest) {
+		struct tracer *saved_tracer = current_trace;
+		struct trace_array_cpu *data;
+		struct trace_array *tr = &global_trace;
+		int saved_ctrl = tr->ctrl;
+		int i;
+		/*
+		 * 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.
+		 */
+		for_each_tracing_cpu(i) {
+			data = tr->data[i];
+			if (!head_page(data))
+				continue;
+			tracing_reset(data);
+		}
+		current_trace = type;
+		tr->ctrl = 0;
+		/* 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 */
+		current_trace = saved_tracer;
+		tr->ctrl = saved_ctrl;
+		if (ret) {
+			printk(KERN_CONT "FAILED!\n");
+			goto out;
+		}
+		/* Only reset on passing, to avoid touching corrupted buffers */
+		for_each_tracing_cpu(i) {
+			data = tr->data[i];
+			if (!head_page(data))
+				continue;
+			tracing_reset(data);
+		}
+		printk(KERN_CONT "PASSED\n");
+	}
+#endif
+
+	type->next = trace_types;
+	trace_types = type;
+	len = strlen(type->name);
+	if (len > max_tracer_type_len)
+		max_tracer_type_len = len;
+
+ out:
+	mutex_unlock(&trace_types_lock);
+
+	return ret;
+}
+
+void unregister_tracer(struct tracer *type)
+{
+	struct tracer **t;
+	int len;
+
+	mutex_lock(&trace_types_lock);
+	for (t = &trace_types; *t; t = &(*t)->next) {
+		if (*t == type)
+			goto found;
+	}
+	pr_info("Trace %s not registered\n", type->name);
+	goto out;
+
+ found:
+	*t = (*t)->next;
+	if (strlen(type->name) != max_tracer_type_len)
+		goto out;
+
+	max_tracer_type_len = 0;
+	for (t = &trace_types; *t; t = &(*t)->next) {
+		len = strlen((*t)->name);
+		if (len > max_tracer_type_len)
+			max_tracer_type_len = len;
+	}
+ out:
+	mutex_unlock(&trace_types_lock);
+}
+
+void tracing_reset(struct trace_array_cpu *data)
+{
+	data->trace_idx = 0;
+	data->overrun = 0;
+	data->trace_head = data->trace_tail = head_page(data);
+	data->trace_head_idx = 0;
+	data->trace_tail_idx = 0;
+}
+
+#define SAVED_CMDLINES 128
+static unsigned map_pid_to_cmdline[PID_MAX_DEFAULT+1];
+static unsigned map_cmdline_to_pid[SAVED_CMDLINES];
+static char saved_cmdlines[SAVED_CMDLINES][TASK_COMM_LEN];
+static int cmdline_idx;
+static DEFINE_SPINLOCK(trace_cmdline_lock);
+
+/* temporary disable recording */
+atomic_t trace_record_cmdline_disabled __read_mostly;
+
+static void trace_init_cmdlines(void)
+{
+	memset(&map_pid_to_cmdline, -1, sizeof(map_pid_to_cmdline));
+	memset(&map_cmdline_to_pid, -1, sizeof(map_cmdline_to_pid));
+	cmdline_idx = 0;
+}
+
+void trace_stop_cmdline_recording(void);
+
+static void trace_save_cmdline(struct task_struct *tsk)
+{
+	unsigned map;
+	unsigned idx;
+
+	if (!tsk->pid || unlikely(tsk->pid > PID_MAX_DEFAULT))
+		return;
+
+	/*
+	 * 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 (!spin_trylock(&trace_cmdline_lock))
+		return;
+
+	idx = map_pid_to_cmdline[tsk->pid];
+	if (idx >= SAVED_CMDLINES) {
+		idx = (cmdline_idx + 1) % SAVED_CMDLINES;
+
+		map = map_cmdline_to_pid[idx];
+		if (map <= PID_MAX_DEFAULT)
+			map_pid_to_cmdline[map] = (unsigned)-1;
+
+		map_pid_to_cmdline[tsk->pid] = idx;
+
+		cmdline_idx = idx;
+	}
+
+	memcpy(&saved_cmdlines[idx], tsk->comm, TASK_COMM_LEN);
+
+	spin_unlock(&trace_cmdline_lock);
+}
+
+static char *trace_find_cmdline(int pid)
+{
+	char *cmdline = "<...>";
+	unsigned map;
+
+	if (!pid)
+		return "<idle>";
+
+	if (pid > PID_MAX_DEFAULT)
+		goto out;
+
+	map = map_pid_to_cmdline[pid];
+	if (map >= SAVED_CMDLINES)
+		goto out;
+
+	cmdline = saved_cmdlines[map];
+
+ out:
+	return cmdline;
+}
+
+void tracing_record_cmdline(struct task_struct *tsk)
+{
+	if (atomic_read(&trace_record_cmdline_disabled))
+		return;
+
+	trace_save_cmdline(tsk);
+}
+
+static inline struct list_head *
+trace_next_list(struct trace_array_cpu *data, struct list_head *next)
+{
+	/*
+	 * Roundrobin - but skip the head (which is not a real page):
+	 */
+	next = next->next;
+	if (unlikely(next == &data->trace_pages))
+		next = next->next;
+	BUG_ON(next == &data->trace_pages);
+
+	return next;
+}
+
+static inline void *
+trace_next_page(struct trace_array_cpu *data, void *addr)
+{
+	struct list_head *next;
+	struct page *page;
+
+	page = virt_to_page(addr);
+
+	next = trace_next_list(data, &page->lru);
+	page = list_entry(next, struct page, lru);
+
+	return page_address(page);
+}
+
+static inline struct trace_entry *
+tracing_get_trace_entry(struct trace_array *tr, struct trace_array_cpu *data)
+{
+	unsigned long idx, idx_next;
+	struct trace_entry *entry;
+
+	data->trace_idx++;
+	idx = data->trace_head_idx;
+	idx_next = idx + 1;
+
+	BUG_ON(idx * TRACE_ENTRY_SIZE >= PAGE_SIZE);
+
+	entry = data->trace_head + idx * TRACE_ENTRY_SIZE;
+
+	if (unlikely(idx_next >= ENTRIES_PER_PAGE)) {
+		data->trace_head = trace_next_page(data, data->trace_head);
+		idx_next = 0;
+	}
+
+	if (data->trace_head == data->trace_tail &&
+	    idx_next == data->trace_tail_idx) {
+		/* overrun */
+		data->overrun++;
+		data->trace_tail_idx++;
+		if (data->trace_tail_idx >= ENTRIES_PER_PAGE) {
+			data->trace_tail =
+				trace_next_page(data, data->trace_tail);
+			data->trace_tail_idx = 0;
+		}
+	}
+
+	data->trace_head_idx = idx_next;
+
+	return entry;
+}
+
+static inline void
+tracing_generic_entry_update(struct trace_entry *entry, unsigned long flags)
+{
+	struct task_struct *tsk = current;
+	unsigned long pc;
+
+	pc = preempt_count();
+
+	entry->preempt_count	= pc & 0xff;
+	entry->pid		= (tsk) ? tsk->pid : 0;
+	entry->t		= ftrace_now(raw_smp_processor_id());
+	entry->flags = (irqs_disabled_flags(flags) ? TRACE_FLAG_IRQS_OFF : 0) |
+		((pc & HARDIRQ_MASK) ? TRACE_FLAG_HARDIRQ : 0) |
+		((pc & SOFTIRQ_MASK) ? TRACE_FLAG_SOFTIRQ : 0) |
+		(need_resched() ? TRACE_FLAG_NEED_RESCHED : 0);
+}
+
+void
+trace_function(struct trace_array *tr, struct trace_array_cpu *data,
+	       unsigned long ip, unsigned long parent_ip, unsigned long flags)
+{
+	struct trace_entry *entry;
+	unsigned long irq_flags;
+
+	raw_local_irq_save(irq_flags);
+	__raw_spin_lock(&data->lock);
+	entry			= tracing_get_trace_entry(tr, data);
+	tracing_generic_entry_update(entry, flags);
+	entry->type		= TRACE_FN;
+	entry->fn.ip		= ip;
+	entry->fn.parent_ip	= parent_ip;
+	__raw_spin_unlock(&data->lock);
+	raw_local_irq_restore(irq_flags);
+}
+
+void
+ftrace(struct trace_array *tr, struct trace_array_cpu *data,
+       unsigned long ip, unsigned long parent_ip, unsigned long flags)
+{
+	if (likely(!atomic_read(&data->disabled)))
+		trace_function(tr, data, ip, parent_ip, flags);
+}
+
+#ifdef CONFIG_MMIOTRACE
+void __trace_mmiotrace_rw(struct trace_array *tr, struct trace_array_cpu *data,
+						struct mmiotrace_rw *rw)
+{
+	struct trace_entry *entry;
+	unsigned long irq_flags;
+
+	raw_local_irq_save(irq_flags);
+	__raw_spin_lock(&data->lock);
+
+	entry			= tracing_get_trace_entry(tr, data);
+	tracing_generic_entry_update(entry, 0);
+	entry->type		= TRACE_MMIO_RW;
+	entry->mmiorw		= *rw;
+
+	__raw_spin_unlock(&data->lock);
+	raw_local_irq_restore(irq_flags);
+
+	trace_wake_up();
+}
+
+void __trace_mmiotrace_map(struct trace_array *tr, struct trace_array_cpu *data,
+						struct mmiotrace_map *map)
+{
+	struct trace_entry *entry;
+	unsigned long irq_flags;
+
+	raw_local_irq_save(irq_flags);
+	__raw_spin_lock(&data->lock);
+
+	entry			= tracing_get_trace_entry(tr, data);
+	tracing_generic_entry_update(entry, 0);
+	entry->type		= TRACE_MMIO_MAP;
+	entry->mmiomap		= *map;
+
+	__raw_spin_unlock(&data->lock);
+	raw_local_irq_restore(irq_flags);
+
+	trace_wake_up();
+}
+#endif
+
+void __trace_stack(struct trace_array *tr,
+		   struct trace_array_cpu *data,
+		   unsigned long flags,
+		   int skip)
+{
+	struct trace_entry *entry;
+	struct stack_trace trace;
+
+	if (!(trace_flags & TRACE_ITER_STACKTRACE))
+		return;
+
+	entry			= tracing_get_trace_entry(tr, data);
+	tracing_generic_entry_update(entry, flags);
+	entry->type		= TRACE_STACK;
+
+	memset(&entry->stack, 0, sizeof(entry->stack));
+
+	trace.nr_entries	= 0;
+	trace.max_entries	= FTRACE_STACK_ENTRIES;
+	trace.skip		= skip;
+	trace.entries		= entry->stack.caller;
+
+	save_stack_trace(&trace);
+}
+
+void
+__trace_special(void *__tr, void *__data,
+		unsigned long arg1, unsigned long arg2, unsigned long arg3)
+{
+	struct trace_array_cpu *data = __data;
+	struct trace_array *tr = __tr;
+	struct trace_entry *entry;
+	unsigned long irq_flags;
+
+	raw_local_irq_save(irq_flags);
+	__raw_spin_lock(&data->lock);
+	entry			= tracing_get_trace_entry(tr, data);
+	tracing_generic_entry_update(entry, 0);
+	entry->type		= TRACE_SPECIAL;
+	entry->special.arg1	= arg1;
+	entry->special.arg2	= arg2;
+	entry->special.arg3	= arg3;
+	__trace_stack(tr, data, irq_flags, 4);
+	__raw_spin_unlock(&data->lock);
+	raw_local_irq_restore(irq_flags);
+
+	trace_wake_up();
+}
+
+void
+tracing_sched_switch_trace(struct trace_array *tr,
+			   struct trace_array_cpu *data,
+			   struct task_struct *prev,
+			   struct task_struct *next,
+			   unsigned long flags)
+{
+	struct trace_entry *entry;
+	unsigned long irq_flags;
+
+	raw_local_irq_save(irq_flags);
+	__raw_spin_lock(&data->lock);
+	entry			= tracing_get_trace_entry(tr, data);
+	tracing_generic_entry_update(entry, flags);
+	entry->type		= TRACE_CTX;
+	entry->ctx.prev_pid	= prev->pid;
+	entry->ctx.prev_prio	= prev->prio;
+	entry->ctx.prev_state	= prev->state;
+	entry->ctx.next_pid	= next->pid;
+	entry->ctx.next_prio	= next->prio;
+	entry->ctx.next_state	= next->state;
+	__trace_stack(tr, data, flags, 5);
+	__raw_spin_unlock(&data->lock);
+	raw_local_irq_restore(irq_flags);
+}
+
+void
+tracing_sched_wakeup_trace(struct trace_array *tr,
+			   struct trace_array_cpu *data,
+			   struct task_struct *wakee,
+			   struct task_struct *curr,
+			   unsigned long flags)
+{
+	struct trace_entry *entry;
+	unsigned long irq_flags;
+
+	raw_local_irq_save(irq_flags);
+	__raw_spin_lock(&data->lock);
+	entry			= tracing_get_trace_entry(tr, data);
+	tracing_generic_entry_update(entry, flags);
+	entry->type		= TRACE_WAKE;
+	entry->ctx.prev_pid	= curr->pid;
+	entry->ctx.prev_prio	= curr->prio;
+	entry->ctx.prev_state	= curr->state;
+	entry->ctx.next_pid	= wakee->pid;
+	entry->ctx.next_prio	= wakee->prio;
+	entry->ctx.next_state	= wakee->state;
+	__trace_stack(tr, data, flags, 6);
+	__raw_spin_unlock(&data->lock);
+	raw_local_irq_restore(irq_flags);
+
+	trace_wake_up();
+}
+
+void
+ftrace_special(unsigned long arg1, unsigned long arg2, unsigned long arg3)
+{
+	struct trace_array *tr = &global_trace;
+	struct trace_array_cpu *data;
+	unsigned long flags;
+	long disabled;
+	int cpu;
+
+	if (tracing_disabled || current_trace == &no_tracer || !tr->ctrl)
+		return;
+
+	local_irq_save(flags);
+	cpu = raw_smp_processor_id();
+	data = tr->data[cpu];
+	disabled = atomic_inc_return(&data->disabled);
+
+	if (likely(disabled == 1))
+		__trace_special(tr, data, arg1, arg2, arg3);
+
+	atomic_dec(&data->disabled);
+	local_irq_restore(flags);
+}
+
+#ifdef CONFIG_FTRACE
+static void
+function_trace_call(unsigned long ip, unsigned long parent_ip)
+{
+	struct trace_array *tr = &global_trace;
+	struct trace_array_cpu *data;
+	unsigned long flags;
+	long disabled;
+	int cpu;
+
+	if (unlikely(!ftrace_function_enabled))
+		return;
+
+	if (skip_trace(ip))
+		return;
+
+	local_irq_save(flags);
+	cpu = raw_smp_processor_id();
+	data = tr->data[cpu];
+	disabled = atomic_inc_return(&data->disabled);
+
+	if (likely(disabled == 1))
+		trace_function(tr, data, ip, parent_ip, flags);
+
+	atomic_dec(&data->disabled);
+	local_irq_restore(flags);
+}
+
+static struct ftrace_ops trace_ops __read_mostly =
+{
+	.func = function_trace_call,
+};
+
+void tracing_start_function_trace(void)
+{
+	ftrace_function_enabled = 0;
+	register_ftrace_function(&trace_ops);
+	if (tracer_enabled)
+		ftrace_function_enabled = 1;
+}
+
+void tracing_stop_function_trace(void)
+{
+	ftrace_function_enabled = 0;
+	unregister_ftrace_function(&trace_ops);
+}
+#endif
+
+enum trace_file_type {
+	TRACE_FILE_LAT_FMT	= 1,
+};
+
+static struct trace_entry *
+trace_entry_idx(struct trace_array *tr, struct trace_array_cpu *data,
+		struct trace_iterator *iter, int cpu)
+{
+	struct page *page;
+	struct trace_entry *array;
+
+	if (iter->next_idx[cpu] >= tr->entries ||
+	    iter->next_idx[cpu] >= data->trace_idx ||
+	    (data->trace_head == data->trace_tail &&
+	     data->trace_head_idx == data->trace_tail_idx))
+		return NULL;
+
+	if (!iter->next_page[cpu]) {
+		/* Initialize the iterator for this cpu trace buffer */
+		WARN_ON(!data->trace_tail);
+		page = virt_to_page(data->trace_tail);
+		iter->next_page[cpu] = &page->lru;
+		iter->next_page_idx[cpu] = data->trace_tail_idx;
+	}
+
+	page = list_entry(iter->next_page[cpu], struct page, lru);
+	BUG_ON(&data->trace_pages == &page->lru);
+
+	array = page_address(page);
+
+	WARN_ON(iter->next_page_idx[cpu] >= ENTRIES_PER_PAGE);
+	return &array[iter->next_page_idx[cpu]];
+}
+
+static struct trace_entry *
+find_next_entry(struct trace_iterator *iter, int *ent_cpu)
+{
+	struct trace_array *tr = iter->tr;
+	struct trace_entry *ent, *next = NULL;
+	int next_cpu = -1;
+	int cpu;
+
+	for_each_tracing_cpu(cpu) {
+		if (!head_page(tr->data[cpu]))
+			continue;
+		ent = trace_entry_idx(tr, tr->data[cpu], iter, cpu);
+		/*
+		 * Pick the entry with the smallest timestamp:
+		 */
+		if (ent && (!next || ent->t < next->t)) {
+			next = ent;
+			next_cpu = cpu;
+		}
+	}
+
+	if (ent_cpu)
+		*ent_cpu = next_cpu;
+
+	return next;
+}
+
+static void trace_iterator_increment(struct trace_iterator *iter)
+{
+	iter->idx++;
+	iter->next_idx[iter->cpu]++;
+	iter->next_page_idx[iter->cpu]++;
+
+	if (iter->next_page_idx[iter->cpu] >= ENTRIES_PER_PAGE) {
+		struct trace_array_cpu *data = iter->tr->data[iter->cpu];
+
+		iter->next_page_idx[iter->cpu] = 0;
+		iter->next_page[iter->cpu] =
+			trace_next_list(data, iter->next_page[iter->cpu]);
+	}
+}
+
+static void trace_consume(struct trace_iterator *iter)
+{
+	struct trace_array_cpu *data = iter->tr->data[iter->cpu];
+
+	data->trace_tail_idx++;
+	if (data->trace_tail_idx >= ENTRIES_PER_PAGE) {
+		data->trace_tail = trace_next_page(data, data->trace_tail);
+		data->trace_tail_idx = 0;
+	}
+
+	/* Check if we empty it, then reset the index */
+	if (data->trace_head == data->trace_tail &&
+	    data->trace_head_idx == data->trace_tail_idx)
+		data->trace_idx = 0;
+}
+
+static void *find_next_entry_inc(struct trace_iterator *iter)
+{
+	struct trace_entry *next;
+	int next_cpu = -1;
+
+	next = find_next_entry(iter, &next_cpu);
+
+	iter->prev_ent = iter->ent;
+	iter->prev_cpu = iter->cpu;
+
+	iter->ent = next;
+	iter->cpu = next_cpu;
+
+	if (next)
+		trace_iterator_increment(iter);
+
+	return next ? iter : NULL;
+}
+
+static void *s_next(struct seq_file *m, void *v, loff_t *pos)
+{
+	struct trace_iterator *iter = m->private;
+	void *last_ent = iter->ent;
+	int i = (int)*pos;
+	void *ent;
+
+	(*pos)++;
+
+	/* can't go backwards */
+	if (iter->idx > i)
+		return NULL;
+
+	if (iter->idx < 0)
+		ent = find_next_entry_inc(iter);
+	else
+		ent = iter;
+
+	while (ent && iter->idx < i)
+		ent = find_next_entry_inc(iter);
+
+	iter->pos = *pos;
+
+	if (last_ent && !ent)
+		seq_puts(m, "\n\nvim:ft=help\n");
+
+	return ent;
+}
+
+static void *s_start(struct seq_file *m, loff_t *pos)
+{
+	struct trace_iterator *iter = m->private;
+	void *p = NULL;
+	loff_t l = 0;
+	int i;
+
+	mutex_lock(&trace_types_lock);
+
+	if (!current_trace || current_trace != iter->trace) {
+		mutex_unlock(&trace_types_lock);
+		return NULL;
+	}
+
+	atomic_inc(&trace_record_cmdline_disabled);
+
+	/* let the tracer grab locks here if needed */
+	if (current_trace->start)
+		current_trace->start(iter);
+
+	if (*pos != iter->pos) {
+		iter->ent = NULL;
+		iter->cpu = 0;
+		iter->idx = -1;
+		iter->prev_ent = NULL;
+		iter->prev_cpu = -1;
+
+		for_each_tracing_cpu(i) {
+			iter->next_idx[i] = 0;
+			iter->next_page[i] = NULL;
+		}
+
+		for (p = iter; p && l < *pos; p = s_next(m, p, &l))
+			;
+
+	} else {
+		l = *pos - 1;
+		p = s_next(m, p, &l);
+	}
+
+	return p;
+}
+
+static void s_stop(struct seq_file *m, void *p)
+{
+	struct trace_iterator *iter = m->private;
+
+	atomic_dec(&trace_record_cmdline_disabled);
+
+	/* let the tracer release locks here if needed */
+	if (current_trace && current_trace == iter->trace && iter->trace->stop)
+		iter->trace->stop(iter);
+
+	mutex_unlock(&trace_types_lock);
+}
+
+#define KRETPROBE_MSG "[unknown/kretprobe'd]"
+
+#ifdef CONFIG_KRETPROBES
+static inline int kretprobed(unsigned long addr)
+{
+	return addr == (unsigned long)kretprobe_trampoline;
+}
+#else
+static inline int kretprobed(unsigned long addr)
+{
+	return 0;
+}
+#endif /* CONFIG_KRETPROBES */
+
+static int
+seq_print_sym_short(struct trace_seq *s, const char *fmt, unsigned long address)
+{
+#ifdef CONFIG_KALLSYMS
+	char str[KSYM_SYMBOL_LEN];
+
+	kallsyms_lookup(address, NULL, NULL, NULL, str);
+
+	return trace_seq_printf(s, fmt, str);
+#endif
+	return 1;
+}
+
+static int
+seq_print_sym_offset(struct trace_seq *s, const char *fmt,
+		     unsigned long address)
+{
+#ifdef CONFIG_KALLSYMS
+	char str[KSYM_SYMBOL_LEN];
+
+	sprint_symbol(str, address);
+	return trace_seq_printf(s, fmt, str);
+#endif
+	return 1;
+}
+
+#ifndef CONFIG_64BIT
+# define IP_FMT "%08lx"
+#else
+# define IP_FMT "%016lx"
+#endif
+
+static int
+seq_print_ip_sym(struct trace_seq *s, unsigned long ip, unsigned long sym_flags)
+{
+	int ret;
+
+	if (!ip)
+		return trace_seq_printf(s, "0");
+
+	if (sym_flags & TRACE_ITER_SYM_OFFSET)
+		ret = seq_print_sym_offset(s, "%s", ip);
+	else
+		ret = seq_print_sym_short(s, "%s", ip);
+
+	if (!ret)
+		return 0;
+
+	if (sym_flags & TRACE_ITER_SYM_ADDR)
+		ret = trace_seq_printf(s, " <" IP_FMT ">", ip);
+	return ret;
+}
+
+static void print_lat_help_header(struct seq_file *m)
+{
+	seq_puts(m, "#                _------=> CPU#            \n");
+	seq_puts(m, "#               / _-----=> irqs-off        \n");
+	seq_puts(m, "#              | / _----=> need-resched    \n");
+	seq_puts(m, "#              || / _---=> hardirq/softirq \n");
+	seq_puts(m, "#              ||| / _--=> preempt-depth   \n");
+	seq_puts(m, "#              |||| /                      \n");
+	seq_puts(m, "#              |||||     delay             \n");
+	seq_puts(m, "#  cmd     pid ||||| time  |   caller      \n");
+	seq_puts(m, "#     \\   /    |||||   \\   |   /           \n");
+}
+
+static void print_func_help_header(struct seq_file *m)
+{
+	seq_puts(m, "#           TASK-PID   CPU#    TIMESTAMP  FUNCTION\n");
+	seq_puts(m, "#              | |      |          |         |\n");
+}
+
+
+static void
+print_trace_header(struct seq_file *m, struct trace_iterator *iter)
+{
+	unsigned long sym_flags = (trace_flags & TRACE_ITER_SYM_MASK);
+	struct trace_array *tr = iter->tr;
+	struct trace_array_cpu *data = tr->data[tr->cpu];
+	struct tracer *type = current_trace;
+	unsigned long total   = 0;
+	unsigned long entries = 0;
+	int cpu;
+	const char *name = "preemption";
+
+	if (type)
+		name = type->name;
+
+	for_each_tracing_cpu(cpu) {
+		if (head_page(tr->data[cpu])) {
+			total += tr->data[cpu]->trace_idx;
+			if (tr->data[cpu]->trace_idx > tr->entries)
+				entries += tr->entries;
+			else
+				entries += tr->data[cpu]->trace_idx;
+		}
+	}
+
+	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,
+		   tr->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, 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");
+	}
+
+	seq_puts(m, "\n");
+}
+
+static void
+lat_print_generic(struct trace_seq *s, struct trace_entry *entry, int cpu)
+{
+	int hardirq, softirq;
+	char *comm;
+
+	comm = trace_find_cmdline(entry->pid);
+
+	trace_seq_printf(s, "%8.8s-%-5d ", comm, entry->pid);
+	trace_seq_printf(s, "%d", cpu);
+	trace_seq_printf(s, "%c%c",
+			(entry->flags & TRACE_FLAG_IRQS_OFF) ? 'd' : '.',
+			((entry->flags & TRACE_FLAG_NEED_RESCHED) ? 'N' : '.'));
+
+	hardirq = entry->flags & TRACE_FLAG_HARDIRQ;
+	softirq = entry->flags & TRACE_FLAG_SOFTIRQ;
+	if (hardirq && softirq) {
+		trace_seq_putc(s, 'H');
+	} else {
+		if (hardirq) {
+			trace_seq_putc(s, 'h');
+		} else {
+			if (softirq)
+				trace_seq_putc(s, 's');
+			else
+				trace_seq_putc(s, '.');
+		}
+	}
+
+	if (entry->preempt_count)
+		trace_seq_printf(s, "%x", entry->preempt_count);
+	else
+		trace_seq_puts(s, ".");
+}
+
+unsigned long preempt_mark_thresh = 100;
+
+static void
+lat_print_timestamp(struct trace_seq *s, unsigned long long abs_usecs,
+		    unsigned long rel_usecs)
+{
+	trace_seq_printf(s, " %4lldus", abs_usecs);
+	if (rel_usecs > preempt_mark_thresh)
+		trace_seq_puts(s, "!: ");
+	else if (rel_usecs > 1)
+		trace_seq_puts(s, "+: ");
+	else
+		trace_seq_puts(s, " : ");
+}
+
+static const char state_to_char[] = TASK_STATE_TO_CHAR_STR;
+
+static int
+print_lat_fmt(struct trace_iterator *iter, unsigned int trace_idx, int cpu)
+{
+	struct trace_seq *s = &iter->seq;
+	unsigned long sym_flags = (trace_flags & TRACE_ITER_SYM_MASK);
+	struct trace_entry *next_entry = find_next_entry(iter, NULL);
+	unsigned long verbose = (trace_flags & TRACE_ITER_VERBOSE);
+	struct trace_entry *entry = iter->ent;
+	unsigned long abs_usecs;
+	unsigned long rel_usecs;
+	char *comm;
+	int S, T;
+	int i;
+	unsigned state;
+
+	if (!next_entry)
+		next_entry = entry;
+	rel_usecs = ns2usecs(next_entry->t - entry->t);
+	abs_usecs = ns2usecs(entry->t - iter->tr->time_start);
+
+	if (verbose) {
+		comm = trace_find_cmdline(entry->pid);
+		trace_seq_printf(s, "%16s %5d %d %d %08x %08x [%08lx]"
+				 " %ld.%03ldms (+%ld.%03ldms): ",
+				 comm,
+				 entry->pid, cpu, entry->flags,
+				 entry->preempt_count, trace_idx,
+				 ns2usecs(entry->t),
+				 abs_usecs/1000,
+				 abs_usecs % 1000, rel_usecs/1000,
+				 rel_usecs % 1000);
+	} else {
+		lat_print_generic(s, entry, cpu);
+		lat_print_timestamp(s, abs_usecs, rel_usecs);
+	}
+	switch (entry->type) {
+	case TRACE_FN:
+		seq_print_ip_sym(s, entry->fn.ip, sym_flags);
+		trace_seq_puts(s, " (");
+		if (kretprobed(entry->fn.parent_ip))
+			trace_seq_puts(s, KRETPROBE_MSG);
+		else
+			seq_print_ip_sym(s, entry->fn.parent_ip, sym_flags);
+		trace_seq_puts(s, ")\n");
+		break;
+	case TRACE_CTX:
+	case TRACE_WAKE:
+		T = entry->ctx.next_state < sizeof(state_to_char) ?
+			state_to_char[entry->ctx.next_state] : 'X';
+
+		state = entry->ctx.prev_state ? __ffs(entry->ctx.prev_state) + 1 : 0;
+		S = state < sizeof(state_to_char) - 1 ? state_to_char[state] : 'X';
+		comm = trace_find_cmdline(entry->ctx.next_pid);
+		trace_seq_printf(s, " %5d:%3d:%c %s %5d:%3d:%c %s\n",
+				 entry->ctx.prev_pid,
+				 entry->ctx.prev_prio,
+				 S, entry->type == TRACE_CTX ? "==>" : "  +",
+				 entry->ctx.next_pid,
+				 entry->ctx.next_prio,
+				 T, comm);
+		break;
+	case TRACE_SPECIAL:
+		trace_seq_printf(s, "# %ld %ld %ld\n",
+				 entry->special.arg1,
+				 entry->special.arg2,
+				 entry->special.arg3);
+		break;
+	case TRACE_STACK:
+		for (i = 0; i < FTRACE_STACK_ENTRIES; i++) {
+			if (i)
+				trace_seq_puts(s, " <= ");
+			seq_print_ip_sym(s, entry->stack.caller[i], sym_flags);
+		}
+		trace_seq_puts(s, "\n");
+		break;
+	default:
+		trace_seq_printf(s, "Unknown type %d\n", entry->type);
+	}
+	return 1;
+}
+
+static int print_trace_fmt(struct trace_iterator *iter)
+{
+	struct trace_seq *s = &iter->seq;
+	unsigned long sym_flags = (trace_flags & TRACE_ITER_SYM_MASK);
+	struct trace_entry *entry;
+	unsigned long usec_rem;
+	unsigned long long t;
+	unsigned long secs;
+	char *comm;
+	int ret;
+	int S, T;
+	int i;
+
+	entry = iter->ent;
+
+	comm = trace_find_cmdline(iter->ent->pid);
+
+	t = ns2usecs(entry->t);
+	usec_rem = do_div(t, 1000000ULL);
+	secs = (unsigned long)t;
+
+	ret = trace_seq_printf(s, "%16s-%-5d ", comm, entry->pid);
+	if (!ret)
+		return 0;
+	ret = trace_seq_printf(s, "[%02d] ", iter->cpu);
+	if (!ret)
+		return 0;
+	ret = trace_seq_printf(s, "%5lu.%06lu: ", secs, usec_rem);
+	if (!ret)
+		return 0;
+
+	switch (entry->type) {
+	case TRACE_FN:
+		ret = seq_print_ip_sym(s, entry->fn.ip, sym_flags);
+		if (!ret)
+			return 0;
+		if ((sym_flags & TRACE_ITER_PRINT_PARENT) &&
+						entry->fn.parent_ip) {
+			ret = trace_seq_printf(s, " <-");
+			if (!ret)
+				return 0;
+			if (kretprobed(entry->fn.parent_ip))
+				ret = trace_seq_puts(s, KRETPROBE_MSG);
+			else
+				ret = seq_print_ip_sym(s, entry->fn.parent_ip,
+						       sym_flags);
+			if (!ret)
+				return 0;
+		}
+		ret = trace_seq_printf(s, "\n");
+		if (!ret)
+			return 0;
+		break;
+	case TRACE_CTX:
+	case TRACE_WAKE:
+		S = entry->ctx.prev_state < sizeof(state_to_char) ?
+			state_to_char[entry->ctx.prev_state] : 'X';
+		T = entry->ctx.next_state < sizeof(state_to_char) ?
+			state_to_char[entry->ctx.next_state] : 'X';
+		ret = trace_seq_printf(s, " %5d:%3d:%c %s %5d:%3d:%c\n",
+				       entry->ctx.prev_pid,
+				       entry->ctx.prev_prio,
+				       S,
+				       entry->type == TRACE_CTX ? "==>" : "  +",
+				       entry->ctx.next_pid,
+				       entry->ctx.next_prio,
+				       T);
+		if (!ret)
+			return 0;
+		break;
+	case TRACE_SPECIAL:
+		ret = trace_seq_printf(s, "# %ld %ld %ld\n",
+				 entry->special.arg1,
+				 entry->special.arg2,
+				 entry->special.arg3);
+		if (!ret)
+			return 0;
+		break;
+	case TRACE_STACK:
+		for (i = 0; i < FTRACE_STACK_ENTRIES; i++) {
+			if (i) {
+				ret = trace_seq_puts(s, " <= ");
+				if (!ret)
+					return 0;
+			}
+			ret = seq_print_ip_sym(s, entry->stack.caller[i],
+					       sym_flags);
+			if (!ret)
+				return 0;
+		}
+		ret = trace_seq_puts(s, "\n");
+		if (!ret)
+			return 0;
+		break;
+	}
+	return 1;
+}
+
+static int print_raw_fmt(struct trace_iterator *iter)
+{
+	struct trace_seq *s = &iter->seq;
+	struct trace_entry *entry;
+	int ret;
+	int S, T;
+
+	entry = iter->ent;
+
+	ret = trace_seq_printf(s, "%d %d %llu ",
+		entry->pid, iter->cpu, entry->t);
+	if (!ret)
+		return 0;
+
+	switch (entry->type) {
+	case TRACE_FN:
+		ret = trace_seq_printf(s, "%x %x\n",
+					entry->fn.ip, entry->fn.parent_ip);
+		if (!ret)
+			return 0;
+		break;
+	case TRACE_CTX:
+	case TRACE_WAKE:
+		S = entry->ctx.prev_state < sizeof(state_to_char) ?
+			state_to_char[entry->ctx.prev_state] : 'X';
+		T = entry->ctx.next_state < sizeof(state_to_char) ?
+			state_to_char[entry->ctx.next_state] : 'X';
+		if (entry->type == TRACE_WAKE)
+			S = '+';
+		ret = trace_seq_printf(s, "%d %d %c %d %d %c\n",
+				       entry->ctx.prev_pid,
+				       entry->ctx.prev_prio,
+				       S,
+				       entry->ctx.next_pid,
+				       entry->ctx.next_prio,
+				       T);
+		if (!ret)
+			return 0;
+		break;
+	case TRACE_SPECIAL:
+	case TRACE_STACK:
+		ret = trace_seq_printf(s, "# %ld %ld %ld\n",
+				 entry->special.arg1,
+				 entry->special.arg2,
+				 entry->special.arg3);
+		if (!ret)
+			return 0;
+		break;
+	}
+	return 1;
+}
+
+#define SEQ_PUT_FIELD_RET(s, x)				\
+do {							\
+	if (!trace_seq_putmem(s, &(x), sizeof(x)))	\
+		return 0;				\
+} while (0)
+
+#define SEQ_PUT_HEX_FIELD_RET(s, x)			\
+do {							\
+	if (!trace_seq_putmem_hex(s, &(x), sizeof(x)))	\
+		return 0;				\
+} while (0)
+
+static int print_hex_fmt(struct trace_iterator *iter)
+{
+	struct trace_seq *s = &iter->seq;
+	unsigned char newline = '\n';
+	struct trace_entry *entry;
+	int S, T;
+
+	entry = iter->ent;
+
+	SEQ_PUT_HEX_FIELD_RET(s, entry->pid);
+	SEQ_PUT_HEX_FIELD_RET(s, iter->cpu);
+	SEQ_PUT_HEX_FIELD_RET(s, entry->t);
+
+	switch (entry->type) {
+	case TRACE_FN:
+		SEQ_PUT_HEX_FIELD_RET(s, entry->fn.ip);
+		SEQ_PUT_HEX_FIELD_RET(s, entry->fn.parent_ip);
+		break;
+	case TRACE_CTX:
+	case TRACE_WAKE:
+		S = entry->ctx.prev_state < sizeof(state_to_char) ?
+			state_to_char[entry->ctx.prev_state] : 'X';
+		T = entry->ctx.next_state < sizeof(state_to_char) ?
+			state_to_char[entry->ctx.next_state] : 'X';
+		if (entry->type == TRACE_WAKE)
+			S = '+';
+		SEQ_PUT_HEX_FIELD_RET(s, entry->ctx.prev_pid);
+		SEQ_PUT_HEX_FIELD_RET(s, entry->ctx.prev_prio);
+		SEQ_PUT_HEX_FIELD_RET(s, S);
+		SEQ_PUT_HEX_FIELD_RET(s, entry->ctx.next_pid);
+		SEQ_PUT_HEX_FIELD_RET(s, entry->ctx.next_prio);
+		SEQ_PUT_HEX_FIELD_RET(s, entry->fn.parent_ip);
+		SEQ_PUT_HEX_FIELD_RET(s, T);
+		break;
+	case TRACE_SPECIAL:
+	case TRACE_STACK:
+		SEQ_PUT_HEX_FIELD_RET(s, entry->special.arg1);
+		SEQ_PUT_HEX_FIELD_RET(s, entry->special.arg2);
+		SEQ_PUT_HEX_FIELD_RET(s, entry->special.arg3);
+		break;
+	}
+	SEQ_PUT_FIELD_RET(s, newline);
+
+	return 1;
+}
+
+static int print_bin_fmt(struct trace_iterator *iter)
+{
+	struct trace_seq *s = &iter->seq;
+	struct trace_entry *entry;
+
+	entry = iter->ent;
+
+	SEQ_PUT_FIELD_RET(s, entry->pid);
+	SEQ_PUT_FIELD_RET(s, entry->cpu);
+	SEQ_PUT_FIELD_RET(s, entry->t);
+
+	switch (entry->type) {
+	case TRACE_FN:
+		SEQ_PUT_FIELD_RET(s, entry->fn.ip);
+		SEQ_PUT_FIELD_RET(s, entry->fn.parent_ip);
+		break;
+	case TRACE_CTX:
+		SEQ_PUT_FIELD_RET(s, entry->ctx.prev_pid);
+		SEQ_PUT_FIELD_RET(s, entry->ctx.prev_prio);
+		SEQ_PUT_FIELD_RET(s, entry->ctx.prev_state);
+		SEQ_PUT_FIELD_RET(s, entry->ctx.next_pid);
+		SEQ_PUT_FIELD_RET(s, entry->ctx.next_prio);
+		SEQ_PUT_FIELD_RET(s, entry->ctx.next_state);
+		break;
+	case TRACE_SPECIAL:
+	case TRACE_STACK:
+		SEQ_PUT_FIELD_RET(s, entry->special.arg1);
+		SEQ_PUT_FIELD_RET(s, entry->special.arg2);
+		SEQ_PUT_FIELD_RET(s, entry->special.arg3);
+		break;
+	}
+	return 1;
+}
+
+static int trace_empty(struct trace_iterator *iter)
+{
+	struct trace_array_cpu *data;
+	int cpu;
+
+	for_each_tracing_cpu(cpu) {
+		data = iter->tr->data[cpu];
+
+		if (head_page(data) && data->trace_idx &&
+		    (data->trace_tail != data->trace_head ||
+		     data->trace_tail_idx != data->trace_head_idx))
+			return 0;
+	}
+	return 1;
+}
+
+static int print_trace_line(struct trace_iterator *iter)
+{
+	if (iter->trace && iter->trace->print_line)
+		return iter->trace->print_line(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);
+
+	if (iter->iter_flags & TRACE_FILE_LAT_FMT)
+		return print_lat_fmt(iter, iter->idx, iter->cpu);
+
+	return print_trace_fmt(iter);
+}
+
+static int s_show(struct seq_file *m, void *v)
+{
+	struct trace_iterator *iter = v;
+
+	if (iter->ent == NULL) {
+		if (iter->tr) {
+			seq_printf(m, "# tracer: %s\n", iter->trace->name);
+			seq_puts(m, "#\n");
+		}
+		if (iter->iter_flags & TRACE_FILE_LAT_FMT) {
+			/* print nothing if the buffers are empty */
+			if (trace_empty(iter))
+				return 0;
+			print_trace_header(m, iter);
+			if (!(trace_flags & TRACE_ITER_VERBOSE))
+				print_lat_help_header(m);
+		} else {
+			if (!(trace_flags & TRACE_ITER_VERBOSE))
+				print_func_help_header(m);
+		}
+	} else {
+		print_trace_line(iter);
+		trace_print_seq(m, &iter->seq);
+	}
+
+	return 0;
+}
+
+static 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, int *ret)
+{
+	struct trace_iterator *iter;
+
+	if (tracing_disabled) {
+		*ret = -ENODEV;
+		return NULL;
+	}
+
+	iter = kzalloc(sizeof(*iter), GFP_KERNEL);
+	if (!iter) {
+		*ret = -ENOMEM;
+		goto out;
+	}
+
+	mutex_lock(&trace_types_lock);
+	if (current_trace && current_trace->print_max)
+		iter->tr = &max_tr;
+	else
+		iter->tr = inode->i_private;
+	iter->trace = current_trace;
+	iter->pos = -1;
+
+	/* TODO stop tracer */
+	*ret = seq_open(file, &tracer_seq_ops);
+	if (!*ret) {
+		struct seq_file *m = file->private_data;
+		m->private = iter;
+
+		/* stop the trace while dumping */
+		if (iter->tr->ctrl) {
+			tracer_enabled = 0;
+			ftrace_function_enabled = 0;
+		}
+
+		if (iter->trace && iter->trace->open)
+			iter->trace->open(iter);
+	} else {
+		kfree(iter);
+		iter = NULL;
+	}
+	mutex_unlock(&trace_types_lock);
+
+ out:
+	return iter;
+}
+
+int tracing_open_generic(struct inode *inode, struct file *filp)
+{
+	if (tracing_disabled)
+		return -ENODEV;
+
+	filp->private_data = inode->i_private;
+	return 0;
+}
+
+int tracing_release(struct inode *inode, struct file *file)
+{
+	struct seq_file *m = (struct seq_file *)file->private_data;
+	struct trace_iterator *iter = m->private;
+
+	mutex_lock(&trace_types_lock);
+	if (iter->trace && iter->trace->close)
+		iter->trace->close(iter);
+
+	/* reenable tracing if it was previously enabled */
+	if (iter->tr->ctrl) {
+		tracer_enabled = 1;
+		/*
+		 * It is safe to enable function tracing even if it
+		 * isn't used
+		 */
+		ftrace_function_enabled = 1;
+	}
+	mutex_unlock(&trace_types_lock);
+
+	seq_release(inode, file);
+	kfree(iter);
+	return 0;
+}
+
+static int tracing_open(struct inode *inode, struct file *file)
+{
+	int ret;
+
+	__tracing_open(inode, file, &ret);
+
+	return ret;
+}
+
+static int tracing_lt_open(struct inode *inode, struct file *file)
+{
+	struct trace_iterator *iter;
+	int ret;
+
+	iter = __tracing_open(inode, file, &ret);
+
+	if (!ret)
+		iter->iter_flags |= TRACE_FILE_LAT_FMT;
+
+	return ret;
+}
+
+
+static void *
+t_next(struct seq_file *m, void *v, loff_t *pos)
+{
+	struct tracer *t = m->private;
+
+	(*pos)++;
+
+	if (t)
+		t = t->next;
+
+	m->private = t;
+
+	return t;
+}
+
+static void *t_start(struct seq_file *m, loff_t *pos)
+{
+	struct tracer *t = m->private;
+	loff_t l = 0;
+
+	mutex_lock(&trace_types_lock);
+	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_printf(m, "%s", t->name);
+	if (t->next)
+		seq_putc(m, ' ');
+	else
+		seq_putc(m, '\n');
+
+	return 0;
+}
+
+static 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)
+{
+	int ret;
+
+	if (tracing_disabled)
+		return -ENODEV;
+
+	ret = seq_open(file, &show_traces_seq_ops);
+	if (!ret) {
+		struct seq_file *m = file->private_data;
+		m->private = trace_types;
+	}
+
+	return ret;
+}
+
+static struct file_operations tracing_fops = {
+	.open		= tracing_open,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.release	= tracing_release,
+};
+
+static struct file_operations tracing_lt_fops = {
+	.open		= tracing_lt_open,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.release	= tracing_release,
+};
+
+static struct file_operations show_traces_fops = {
+	.open		= show_traces_open,
+	.read		= seq_read,
+	.release	= seq_release,
+};
+
+/*
+ * Only trace on a CPU if the bitmask is set:
+ */
+static cpumask_t tracing_cpumask = CPU_MASK_ALL;
+
+/*
+ * When tracing/tracing_cpu_mask is modified then this holds
+ * the new bitmask we are about to install:
+ */
+static cpumask_t tracing_cpumask_new;
+
+/*
+ * The tracer itself will not take this lock, but still we want
+ * to provide a consistent cpumask to user-space:
+ */
+static DEFINE_MUTEX(tracing_cpumask_update_lock);
+
+/*
+ * Temporary storage for the character representation of the
+ * CPU bitmask (and one more byte for the newline):
+ */
+static char mask_str[NR_CPUS + 1];
+
+static ssize_t
+tracing_cpumask_read(struct file *filp, char __user *ubuf,
+		     size_t count, loff_t *ppos)
+{
+	int len;
+
+	mutex_lock(&tracing_cpumask_update_lock);
+
+	len = cpumask_scnprintf(mask_str, count, tracing_cpumask);
+	if (count - len < 2) {
+		count = -EINVAL;
+		goto out_err;
+	}
+	len += sprintf(mask_str + len, "\n");
+	count = simple_read_from_buffer(ubuf, count, ppos, mask_str, NR_CPUS+1);
+
+out_err:
+	mutex_unlock(&tracing_cpumask_update_lock);
+
+	return count;
+}
+
+static ssize_t
+tracing_cpumask_write(struct file *filp, const char __user *ubuf,
+		      size_t count, loff_t *ppos)
+{
+	int err, cpu;
+
+	mutex_lock(&tracing_cpumask_update_lock);
+	err = cpumask_parse_user(ubuf, count, tracing_cpumask_new);
+	if (err)
+		goto err_unlock;
+
+	raw_local_irq_disable();
+	__raw_spin_lock(&ftrace_max_lock);
+	for_each_tracing_cpu(cpu) {
+		/*
+		 * Increase/decrease the disabled counter if we are
+		 * about to flip a bit in the cpumask:
+		 */
+		if (cpu_isset(cpu, tracing_cpumask) &&
+				!cpu_isset(cpu, tracing_cpumask_new)) {
+			atomic_inc(&global_trace.data[cpu]->disabled);
+		}
+		if (!cpu_isset(cpu, tracing_cpumask) &&
+				cpu_isset(cpu, tracing_cpumask_new)) {
+			atomic_dec(&global_trace.data[cpu]->disabled);
+		}
+	}
+	__raw_spin_unlock(&ftrace_max_lock);
+	raw_local_irq_enable();
+
+	tracing_cpumask = tracing_cpumask_new;
+
+	mutex_unlock(&tracing_cpumask_update_lock);
+
+	return count;
+
+err_unlock:
+	mutex_unlock(&tracing_cpumask_update_lock);
+
+	return err;
+}
+
+static struct file_operations tracing_cpumask_fops = {
+	.open		= tracing_open_generic,
+	.read		= tracing_cpumask_read,
+	.write		= tracing_cpumask_write,
+};
+
+static ssize_t
+tracing_iter_ctrl_read(struct file *filp, char __user *ubuf,
+		       size_t cnt, loff_t *ppos)
+{
+	char *buf;
+	int r = 0;
+	int len = 0;
+	int i;
+
+	/* calulate max size */
+	for (i = 0; trace_options[i]; i++) {
+		len += strlen(trace_options[i]);
+		len += 3; /* "no" and space */
+	}
+
+	/* +2 for \n and \0 */
+	buf = kmalloc(len + 2, GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
+
+	for (i = 0; trace_options[i]; i++) {
+		if (trace_flags & (1 << i))
+			r += sprintf(buf + r, "%s ", trace_options[i]);
+		else
+			r += sprintf(buf + r, "no%s ", trace_options[i]);
+	}
+
+	r += sprintf(buf + r, "\n");
+	WARN_ON(r >= len + 2);
+
+	r = simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
+
+	kfree(buf);
+
+	return r;
+}
+
+static ssize_t
+tracing_iter_ctrl_write(struct file *filp, const char __user *ubuf,
+			size_t cnt, loff_t *ppos)
+{
+	char buf[64];
+	char *cmp = buf;
+	int neg = 0;
+	int i;
+
+	if (cnt >= sizeof(buf))
+		return -EINVAL;
+
+	if (copy_from_user(&buf, ubuf, cnt))
+		return -EFAULT;
+
+	buf[cnt] = 0;
+
+	if (strncmp(buf, "no", 2) == 0) {
+		neg = 1;
+		cmp += 2;
+	}
+
+	for (i = 0; trace_options[i]; i++) {
+		int len = strlen(trace_options[i]);
+
+		if (strncmp(cmp, trace_options[i], len) == 0) {
+			if (neg)
+				trace_flags &= ~(1 << i);
+			else
+				trace_flags |= (1 << i);
+			break;
+		}
+	}
+	/*
+	 * If no option could be set, return an error:
+	 */
+	if (!trace_options[i])
+		return -EINVAL;
+
+	filp->f_pos += cnt;
+
+	return cnt;
+}
+
+static struct file_operations tracing_iter_fops = {
+	.open		= tracing_open_generic,
+	.read		= tracing_iter_ctrl_read,
+	.write		= tracing_iter_ctrl_write,
+};
+
+static const char readme_msg[] =
+	"tracing mini-HOWTO:\n\n"
+	"# mkdir /debug\n"
+	"# mount -t debugfs nodev /debug\n\n"
+	"# cat /debug/tracing/available_tracers\n"
+	"wakeup preemptirqsoff preemptoff irqsoff ftrace sched_switch none\n\n"
+	"# cat /debug/tracing/current_tracer\n"
+	"none\n"
+	"# echo sched_switch > /debug/tracing/current_tracer\n"
+	"# cat /debug/tracing/current_tracer\n"
+	"sched_switch\n"
+	"# cat /debug/tracing/iter_ctrl\n"
+	"noprint-parent nosym-offset nosym-addr noverbose\n"
+	"# echo print-parent > /debug/tracing/iter_ctrl\n"
+	"# echo 1 > /debug/tracing/tracing_enabled\n"
+	"# cat /debug/tracing/trace > /tmp/trace.txt\n"
+	"echo 0 > /debug/tracing/tracing_enabled\n"
+;
+
+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 struct file_operations tracing_readme_fops = {
+	.open		= tracing_open_generic,
+	.read		= tracing_readme_read,
+};
+
+static ssize_t
+tracing_ctrl_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 = sprintf(buf, "%ld\n", tr->ctrl);
+	return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
+}
+
+static ssize_t
+tracing_ctrl_write(struct file *filp, const char __user *ubuf,
+		   size_t cnt, loff_t *ppos)
+{
+	struct trace_array *tr = filp->private_data;
+	char buf[64];
+	long val;
+	int ret;
+
+	if (cnt >= sizeof(buf))
+		return -EINVAL;
+
+	if (copy_from_user(&buf, ubuf, cnt))
+		return -EFAULT;
+
+	buf[cnt] = 0;
+
+	ret = strict_strtoul(buf, 10, &val);
+	if (ret < 0)
+		return ret;
+
+	val = !!val;
+
+	mutex_lock(&trace_types_lock);
+	if (tr->ctrl ^ val) {
+		if (val)
+			tracer_enabled = 1;
+		else
+			tracer_enabled = 0;
+
+		tr->ctrl = val;
+
+		if (current_trace && current_trace->ctrl_update)
+			current_trace->ctrl_update(tr);
+	}
+	mutex_unlock(&trace_types_lock);
+
+	filp->f_pos += cnt;
+
+	return cnt;
+}
+
+static ssize_t
+tracing_set_trace_read(struct file *filp, char __user *ubuf,
+		       size_t cnt, loff_t *ppos)
+{
+	char buf[max_tracer_type_len+2];
+	int r;
+
+	mutex_lock(&trace_types_lock);
+	if (current_trace)
+		r = sprintf(buf, "%s\n", current_trace->name);
+	else
+		r = sprintf(buf, "\n");
+	mutex_unlock(&trace_types_lock);
+
+	return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
+}
+
+static ssize_t
+tracing_set_trace_write(struct file *filp, const char __user *ubuf,
+			size_t cnt, loff_t *ppos)
+{
+	struct trace_array *tr = &global_trace;
+	struct tracer *t;
+	char buf[max_tracer_type_len+1];
+	int i;
+
+	if (cnt > max_tracer_type_len)
+		cnt = max_tracer_type_len;
+
+	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;
+
+	mutex_lock(&trace_types_lock);
+	for (t = trace_types; t; t = t->next) {
+		if (strcmp(t->name, buf) == 0)
+			break;
+	}
+	if (!t || t == current_trace)
+		goto out;
+
+	if (current_trace && current_trace->reset)
+		current_trace->reset(tr);
+
+	current_trace = t;
+	if (t->init)
+		t->init(tr);
+
+ out:
+	mutex_unlock(&trace_types_lock);
+
+	filp->f_pos += cnt;
+
+	return cnt;
+}
+
+static ssize_t
+tracing_max_lat_read(struct file *filp, char __user *ubuf,
+		     size_t cnt, loff_t *ppos)
+{
+	unsigned long *ptr = filp->private_data;
+	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_max_lat_write(struct file *filp, const char __user *ubuf,
+		      size_t cnt, loff_t *ppos)
+{
+	long *ptr = filp->private_data;
+	char buf[64];
+	long val;
+	int ret;
+
+	if (cnt >= sizeof(buf))
+		return -EINVAL;
+
+	if (copy_from_user(&buf, ubuf, cnt))
+		return -EFAULT;
+
+	buf[cnt] = 0;
+
+	ret = strict_strtoul(buf, 10, &val);
+	if (ret < 0)
+		return ret;
+
+	*ptr = val * 1000;
+
+	return cnt;
+}
+
+static atomic_t tracing_reader;
+
+static int tracing_open_pipe(struct inode *inode, struct file *filp)
+{
+	struct trace_iterator *iter;
+
+	if (tracing_disabled)
+		return -ENODEV;
+
+	/* We only allow for reader of the pipe */
+	if (atomic_inc_return(&tracing_reader) != 1) {
+		atomic_dec(&tracing_reader);
+		return -EBUSY;
+	}
+
+	/* create a buffer to store the information to pass to userspace */
+	iter = kzalloc(sizeof(*iter), GFP_KERNEL);
+	if (!iter)
+		return -ENOMEM;
+
+	mutex_lock(&trace_types_lock);
+	iter->tr = &global_trace;
+	iter->trace = current_trace;
+	filp->private_data = iter;
+
+	if (iter->trace->pipe_open)
+		iter->trace->pipe_open(iter);
+	mutex_unlock(&trace_types_lock);
+
+	return 0;
+}
+
+static int tracing_release_pipe(struct inode *inode, struct file *file)
+{
+	struct trace_iterator *iter = file->private_data;
+
+	kfree(iter);
+	atomic_dec(&tracing_reader);
+
+	return 0;
+}
+
+static unsigned int
+tracing_poll_pipe(struct file *filp, poll_table *poll_table)
+{
+	struct trace_iterator *iter = filp->private_data;
+
+	if (trace_flags & TRACE_ITER_BLOCK) {
+		/*
+		 * Always select as readable when in blocking mode
+		 */
+		return POLLIN | POLLRDNORM;
+	} else {
+		if (!trace_empty(iter))
+			return POLLIN | POLLRDNORM;
+		poll_wait(filp, &trace_wait, poll_table);
+		if (!trace_empty(iter))
+			return POLLIN | POLLRDNORM;
+
+		return 0;
+	}
+}
+
+/*
+ * 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;
+	struct trace_array_cpu *data;
+	static cpumask_t mask;
+	unsigned long flags;
+#ifdef CONFIG_FTRACE
+	int ftrace_save;
+#endif
+	int cpu;
+	ssize_t sret;
+
+	/* return any leftover data */
+	sret = trace_seq_to_user(&iter->seq, ubuf, cnt);
+	if (sret != -EBUSY)
+		return sret;
+	sret = 0;
+
+	trace_seq_reset(&iter->seq);
+
+	mutex_lock(&trace_types_lock);
+	if (iter->trace->read) {
+		sret = iter->trace->read(iter, filp, ubuf, cnt, ppos);
+		if (sret)
+			goto out;
+	}
+
+	while (trace_empty(iter)) {
+
+		if ((filp->f_flags & O_NONBLOCK)) {
+			sret = -EAGAIN;
+			goto out;
+		}
+
+		/*
+		 * This is a make-shift waitqueue. The reason we don't use
+		 * an actual wait queue is because:
+		 *  1) we only ever have one waiter
+		 *  2) the tracing, traces all functions, we don't want
+		 *     the overhead of calling wake_up and friends
+		 *     (and tracing them too)
+		 *     Anyway, this is really very primitive wakeup.
+		 */
+		set_current_state(TASK_INTERRUPTIBLE);
+		iter->tr->waiter = current;
+
+		mutex_unlock(&trace_types_lock);
+
+		/* sleep for 100 msecs, and try again. */
+		schedule_timeout(HZ/10);
+
+		mutex_lock(&trace_types_lock);
+
+		iter->tr->waiter = NULL;
+
+		if (signal_pending(current)) {
+			sret = -EINTR;
+			goto out;
+		}
+
+		if (iter->trace != current_trace)
+			goto out;
+
+		/*
+		 * 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_enabled && iter->pos)
+			break;
+
+		continue;
+	}
+
+	/* stop when tracing is finished */
+	if (trace_empty(iter))
+		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));
+	iter->pos = -1;
+
+	/*
+	 * 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.
+	 */
+
+	cpus_clear(mask);
+	local_irq_save(flags);
+#ifdef CONFIG_FTRACE
+	ftrace_save = ftrace_enabled;
+	ftrace_enabled = 0;
+#endif
+	smp_wmb();
+	for_each_tracing_cpu(cpu) {
+		data = iter->tr->data[cpu];
+
+		if (!head_page(data) || !data->trace_idx)
+			continue;
+
+		atomic_inc(&data->disabled);
+		cpu_set(cpu, mask);
+	}
+
+	for_each_cpu_mask(cpu, mask) {
+		data = iter->tr->data[cpu];
+		__raw_spin_lock(&data->lock);
+
+		if (data->overrun > iter->last_overrun[cpu])
+			iter->overrun[cpu] +=
+				data->overrun - iter->last_overrun[cpu];
+		iter->last_overrun[cpu] = data->overrun;
+	}
+
+	while (find_next_entry_inc(iter) != NULL) {
+		int ret;
+		int len = iter->seq.len;
+
+		ret = print_trace_line(iter);
+		if (!ret) {
+			/* don't print partial lines */
+			iter->seq.len = len;
+			break;
+		}
+
+		trace_consume(iter);
+
+		if (iter->seq.len >= cnt)
+			break;
+	}
+
+	for_each_cpu_mask(cpu, mask) {
+		data = iter->tr->data[cpu];
+		__raw_spin_unlock(&data->lock);
+	}
+
+	for_each_cpu_mask(cpu, mask) {
+		data = iter->tr->data[cpu];
+		atomic_dec(&data->disabled);
+	}
+#ifdef CONFIG_FTRACE
+	ftrace_enabled = ftrace_save;
+#endif
+	local_irq_restore(flags);
+
+	/* Now copy what we have to the user */
+	sret = trace_seq_to_user(&iter->seq, ubuf, cnt);
+	if (iter->seq.readpos >= iter->seq.len)
+		trace_seq_reset(&iter->seq);
+	if (sret == -EBUSY)
+		sret = 0;
+
+out:
+	mutex_unlock(&trace_types_lock);
+
+	return sret;
+}
+
+static ssize_t
+tracing_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;
+
+	r = sprintf(buf, "%lu\n", tr->entries);
+	return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
+}
+
+static ssize_t
+tracing_entries_write(struct file *filp, const char __user *ubuf,
+		      size_t cnt, loff_t *ppos)
+{
+	unsigned long val;
+	char buf[64];
+	int i, ret;
+
+	if (cnt >= sizeof(buf))
+		return -EINVAL;
+
+	if (copy_from_user(&buf, ubuf, cnt))
+		return -EFAULT;
+
+	buf[cnt] = 0;
+
+	ret = strict_strtoul(buf, 10, &val);
+	if (ret < 0)
+		return ret;
+
+	/* must have at least 1 entry */
+	if (!val)
+		return -EINVAL;
+
+	mutex_lock(&trace_types_lock);
+
+	if (current_trace != &no_tracer) {
+		cnt = -EBUSY;
+		pr_info("ftrace: set current_tracer to none"
+			" before modifying buffer size\n");
+		goto out;
+	}
+
+	if (val > global_trace.entries) {
+		long pages_requested;
+		unsigned long freeable_pages;
+
+		/* make sure we have enough memory before mapping */
+		pages_requested =
+			(val + (ENTRIES_PER_PAGE-1)) / ENTRIES_PER_PAGE;
+
+		/* account for each buffer (and max_tr) */
+		pages_requested *= tracing_nr_buffers * 2;
+
+		/* Check for overflow */
+		if (pages_requested < 0) {
+			cnt = -ENOMEM;
+			goto out;
+		}
+
+		freeable_pages = determine_dirtyable_memory();
+
+		/* we only allow to request 1/4 of useable memory */
+		if (pages_requested >
+		    ((freeable_pages + tracing_pages_allocated) / 4)) {
+			cnt = -ENOMEM;
+			goto out;
+		}
+
+		while (global_trace.entries < val) {
+			if (trace_alloc_page()) {
+				cnt = -ENOMEM;
+				goto out;
+			}
+			/* double check that we don't go over the known pages */
+			if (tracing_pages_allocated > pages_requested)
+				break;
+		}
+
+	} else {
+		/* include the number of entries in val (inc of page entries) */
+		while (global_trace.entries > val + (ENTRIES_PER_PAGE - 1))
+			trace_free_page();
+	}
+
+	/* check integrity */
+	for_each_tracing_cpu(i)
+		check_pages(global_trace.data[i]);
+
+	filp->f_pos += cnt;
+
+	/* If check pages failed, return ENOMEM */
+	if (tracing_disabled)
+		cnt = -ENOMEM;
+ out:
+	max_tr.entries = global_trace.entries;
+	mutex_unlock(&trace_types_lock);
+
+	return cnt;
+}
+
+static struct file_operations tracing_max_lat_fops = {
+	.open		= tracing_open_generic,
+	.read		= tracing_max_lat_read,
+	.write		= tracing_max_lat_write,
+};
+
+static struct file_operations tracing_ctrl_fops = {
+	.open		= tracing_open_generic,
+	.read		= tracing_ctrl_read,
+	.write		= tracing_ctrl_write,
+};
+
+static struct file_operations set_tracer_fops = {
+	.open		= tracing_open_generic,
+	.read		= tracing_set_trace_read,
+	.write		= tracing_set_trace_write,
+};
+
+static struct file_operations tracing_pipe_fops = {
+	.open		= tracing_open_pipe,
+	.poll		= tracing_poll_pipe,
+	.read		= tracing_read_pipe,
+	.release	= tracing_release_pipe,
+};
+
+static struct file_operations tracing_entries_fops = {
+	.open		= tracing_open_generic,
+	.read		= tracing_entries_read,
+	.write		= tracing_entries_write,
+};
+
+#ifdef CONFIG_DYNAMIC_FTRACE
+
+static ssize_t
+tracing_read_long(struct file *filp, char __user *ubuf,
+		  size_t cnt, loff_t *ppos)
+{
+	unsigned long *p = filp->private_data;
+	char buf[64];
+	int r;
+
+	r = sprintf(buf, "%ld\n", *p);
+
+	return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
+}
+
+static struct file_operations tracing_read_long_fops = {
+	.open		= tracing_open_generic,
+	.read		= tracing_read_long,
+};
+#endif
+
+static struct dentry *d_tracer;
+
+struct dentry *tracing_init_dentry(void)
+{
+	static int once;
+
+	if (d_tracer)
+		return d_tracer;
+
+	d_tracer = debugfs_create_dir("tracing", NULL);
+
+	if (!d_tracer && !once) {
+		once = 1;
+		pr_warning("Could not create debugfs directory 'tracing'\n");
+		return NULL;
+	}
+
+	return d_tracer;
+}
+
+#ifdef CONFIG_FTRACE_SELFTEST
+/* Let selftest have access to static functions in this file */
+#include "trace_selftest.c"
+#endif
+
+static __init void tracer_init_debugfs(void)
+{
+	struct dentry *d_tracer;
+	struct dentry *entry;
+
+	d_tracer = tracing_init_dentry();
+
+	entry = debugfs_create_file("tracing_enabled", 0644, d_tracer,
+				    &global_trace, &tracing_ctrl_fops);
+	if (!entry)
+		pr_warning("Could not create debugfs 'tracing_enabled' entry\n");
+
+	entry = debugfs_create_file("iter_ctrl", 0644, d_tracer,
+				    NULL, &tracing_iter_fops);
+	if (!entry)
+		pr_warning("Could not create debugfs 'iter_ctrl' entry\n");
+
+	entry = debugfs_create_file("tracing_cpumask", 0644, d_tracer,
+				    NULL, &tracing_cpumask_fops);
+	if (!entry)
+		pr_warning("Could not create debugfs 'tracing_cpumask' entry\n");
+
+	entry = debugfs_create_file("latency_trace", 0444, d_tracer,
+				    &global_trace, &tracing_lt_fops);
+	if (!entry)
+		pr_warning("Could not create debugfs 'latency_trace' entry\n");
+
+	entry = debugfs_create_file("trace", 0444, d_tracer,
+				    &global_trace, &tracing_fops);
+	if (!entry)
+		pr_warning("Could not create debugfs 'trace' entry\n");
+
+	entry = debugfs_create_file("available_tracers", 0444, d_tracer,
+				    &global_trace, &show_traces_fops);
+	if (!entry)
+		pr_warning("Could not create debugfs 'trace' entry\n");
+
+	entry = debugfs_create_file("current_tracer", 0444, d_tracer,
+				    &global_trace, &set_tracer_fops);
+	if (!entry)
+		pr_warning("Could not create debugfs 'trace' entry\n");
+
+	entry = debugfs_create_file("tracing_max_latency", 0644, d_tracer,
+				    &tracing_max_latency,
+				    &tracing_max_lat_fops);
+	if (!entry)
+		pr_warning("Could not create debugfs "
+			   "'tracing_max_latency' entry\n");
+
+	entry = debugfs_create_file("tracing_thresh", 0644, d_tracer,
+				    &tracing_thresh, &tracing_max_lat_fops);
+	if (!entry)
+		pr_warning("Could not create debugfs "
+			   "'tracing_threash' entry\n");
+	entry = debugfs_create_file("README", 0644, d_tracer,
+				    NULL, &tracing_readme_fops);
+	if (!entry)
+		pr_warning("Could not create debugfs 'README' entry\n");
+
+	entry = debugfs_create_file("trace_pipe", 0644, d_tracer,
+				    NULL, &tracing_pipe_fops);
+	if (!entry)
+		pr_warning("Could not create debugfs "
+			   "'tracing_threash' entry\n");
+
+	entry = debugfs_create_file("trace_entries", 0644, d_tracer,
+				    &global_trace, &tracing_entries_fops);
+	if (!entry)
+		pr_warning("Could not create debugfs "
+			   "'tracing_threash' entry\n");
+
+#ifdef CONFIG_DYNAMIC_FTRACE
+	entry = debugfs_create_file("dyn_ftrace_total_info", 0444, d_tracer,
+				    &ftrace_update_tot_cnt,
+				    &tracing_read_long_fops);
+	if (!entry)
+		pr_warning("Could not create debugfs "
+			   "'dyn_ftrace_total_info' entry\n");
+#endif
+#ifdef CONFIG_SYSPROF_TRACER
+	init_tracer_sysprof_debugfs(d_tracer);
+#endif
+}
+
+static int trace_alloc_page(void)
+{
+	struct trace_array_cpu *data;
+	struct page *page, *tmp;
+	LIST_HEAD(pages);
+	void *array;
+	unsigned pages_allocated = 0;
+	int i;
+
+	/* first allocate a page for each CPU */
+	for_each_tracing_cpu(i) {
+		array = (void *)__get_free_page(GFP_KERNEL);
+		if (array == NULL) {
+			printk(KERN_ERR "tracer: failed to allocate page"
+			       "for trace buffer!\n");
+			goto free_pages;
+		}
+
+		pages_allocated++;
+		page = virt_to_page(array);
+		list_add(&page->lru, &pages);
+
+/* Only allocate if we are actually using the max trace */
+#ifdef CONFIG_TRACER_MAX_TRACE
+		array = (void *)__get_free_page(GFP_KERNEL);
+		if (array == NULL) {
+			printk(KERN_ERR "tracer: failed to allocate page"
+			       "for trace buffer!\n");
+			goto free_pages;
+		}
+		pages_allocated++;
+		page = virt_to_page(array);
+		list_add(&page->lru, &pages);
+#endif
+	}
+
+	/* Now that we successfully allocate a page per CPU, add them */
+	for_each_tracing_cpu(i) {
+		data = global_trace.data[i];
+		page = list_entry(pages.next, struct page, lru);
+		list_del_init(&page->lru);
+		list_add_tail(&page->lru, &data->trace_pages);
+		ClearPageLRU(page);
+
+#ifdef CONFIG_TRACER_MAX_TRACE
+		data = max_tr.data[i];
+		page = list_entry(pages.next, struct page, lru);
+		list_del_init(&page->lru);
+		list_add_tail(&page->lru, &data->trace_pages);
+		SetPageLRU(page);
+#endif
+	}
+	tracing_pages_allocated += pages_allocated;
+	global_trace.entries += ENTRIES_PER_PAGE;
+
+	return 0;
+
+ free_pages:
+	list_for_each_entry_safe(page, tmp, &pages, lru) {
+		list_del_init(&page->lru);
+		__free_page(page);
+	}
+	return -ENOMEM;
+}
+
+static int trace_free_page(void)
+{
+	struct trace_array_cpu *data;
+	struct page *page;
+	struct list_head *p;
+	int i;
+	int ret = 0;
+
+	/* free one page from each buffer */
+	for_each_tracing_cpu(i) {
+		data = global_trace.data[i];
+		p = data->trace_pages.next;
+		if (p == &data->trace_pages) {
+			/* should never happen */
+			WARN_ON(1);
+			tracing_disabled = 1;
+			ret = -1;
+			break;
+		}
+		page = list_entry(p, struct page, lru);
+		ClearPageLRU(page);
+		list_del(&page->lru);
+		tracing_pages_allocated--;
+		tracing_pages_allocated--;
+		__free_page(page);
+
+		tracing_reset(data);
+
+#ifdef CONFIG_TRACER_MAX_TRACE
+		data = max_tr.data[i];
+		p = data->trace_pages.next;
+		if (p == &data->trace_pages) {
+			/* should never happen */
+			WARN_ON(1);
+			tracing_disabled = 1;
+			ret = -1;
+			break;
+		}
+		page = list_entry(p, struct page, lru);
+		ClearPageLRU(page);
+		list_del(&page->lru);
+		__free_page(page);
+
+		tracing_reset(data);
+#endif
+	}
+	global_trace.entries -= ENTRIES_PER_PAGE;
+
+	return ret;
+}
+
+__init static int tracer_alloc_buffers(void)
+{
+	struct trace_array_cpu *data;
+	void *array;
+	struct page *page;
+	int pages = 0;
+	int ret = -ENOMEM;
+	int i;
+
+	/* TODO: make the number of buffers hot pluggable with CPUS */
+	tracing_nr_buffers = num_possible_cpus();
+	tracing_buffer_mask = cpu_possible_map;
+
+	/* Allocate the first page for all buffers */
+	for_each_tracing_cpu(i) {
+		data = global_trace.data[i] = &per_cpu(global_trace_cpu, i);
+		max_tr.data[i] = &per_cpu(max_data, i);
+
+		array = (void *)__get_free_page(GFP_KERNEL);
+		if (array == NULL) {
+			printk(KERN_ERR "tracer: failed to allocate page"
+			       "for trace buffer!\n");
+			goto free_buffers;
+		}
+
+		/* set the array to the list */
+		INIT_LIST_HEAD(&data->trace_pages);
+		page = virt_to_page(array);
+		list_add(&page->lru, &data->trace_pages);
+		/* use the LRU flag to differentiate the two buffers */
+		ClearPageLRU(page);
+
+		data->lock = (raw_spinlock_t)__RAW_SPIN_LOCK_UNLOCKED;
+		max_tr.data[i]->lock = (raw_spinlock_t)__RAW_SPIN_LOCK_UNLOCKED;
+
+/* Only allocate if we are actually using the max trace */
+#ifdef CONFIG_TRACER_MAX_TRACE
+		array = (void *)__get_free_page(GFP_KERNEL);
+		if (array == NULL) {
+			printk(KERN_ERR "tracer: failed to allocate page"
+			       "for trace buffer!\n");
+			goto free_buffers;
+		}
+
+		INIT_LIST_HEAD(&max_tr.data[i]->trace_pages);
+		page = virt_to_page(array);
+		list_add(&page->lru, &max_tr.data[i]->trace_pages);
+		SetPageLRU(page);
+#endif
+	}
+
+	/*
+	 * Since we allocate by orders of pages, we may be able to
+	 * round up a bit.
+	 */
+	global_trace.entries = ENTRIES_PER_PAGE;
+	pages++;
+
+	while (global_trace.entries < trace_nr_entries) {
+		if (trace_alloc_page())
+			break;
+		pages++;
+	}
+	max_tr.entries = global_trace.entries;
+
+	pr_info("tracer: %d pages allocated for %ld entries of %ld bytes\n",
+		pages, trace_nr_entries, (long)TRACE_ENTRY_SIZE);
+	pr_info("   actual entries %ld\n", global_trace.entries);
+
+	tracer_init_debugfs();
+
+	trace_init_cmdlines();
+
+	register_tracer(&no_tracer);
+	current_trace = &no_tracer;
+
+	/* All seems OK, enable tracing */
+	global_trace.ctrl = tracer_enabled;
+	tracing_disabled = 0;
+
+	return 0;
+
+ free_buffers:
+	for (i-- ; i >= 0; i--) {
+		struct page *page, *tmp;
+		struct trace_array_cpu *data = global_trace.data[i];
+
+		if (data) {
+			list_for_each_entry_safe(page, tmp,
+						 &data->trace_pages, lru) {
+				list_del_init(&page->lru);
+				__free_page(page);
+			}
+		}
+
+#ifdef CONFIG_TRACER_MAX_TRACE
+		data = max_tr.data[i];
+		if (data) {
+			list_for_each_entry_safe(page, tmp,
+						 &data->trace_pages, lru) {
+				list_del_init(&page->lru);
+				__free_page(page);
+			}
+		}
+#endif
+	}
+	return ret;
+}
+fs_initcall(tracer_alloc_buffers);