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-rw-r--r--kernel/trace/trace.c3161
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);