unsigned long __read_mostly tracing_max_latency = (cycle_t)ULONG_MAX;
unsigned long __read_mostly tracing_thresh;
+
+/*
+ * Kill all tracing for good (never come back).
+ * It is initialized to 1 but will turn to zero if the initialization
+ * of the tracer is successful. But that is the only place that sets
+ * this back to zero.
+ */
+int tracing_disabled = 1;
+
static DEFINE_PER_CPU(local_t, ftrace_cpu_disabled);
static inline void ftrace_disable_cpu(void)
#define for_each_tracing_cpu(cpu) \
for_each_cpu_mask(cpu, tracing_buffer_mask)
-static int tracing_disabled = 1;
+/*
+ * ftrace_dump_on_oops - variable to dump ftrace buffer on oops
+ *
+ * If there is an oops (or kernel panic) and the ftrace_dump_on_oops
+ * is set, then ftrace_dump is called. This will output the contents
+ * of the ftrace buffers to the console. This is very useful for
+ * capturing traces that lead to crashes and outputing it to a
+ * serial console.
+ *
+ * It is default off, but you can enable it with either specifying
+ * "ftrace_dump_on_oops" in the kernel command line, or setting
+ * /proc/sys/kernel/ftrace_dump_on_oops to true.
+ */
+int ftrace_dump_on_oops;
+
+static int tracing_set_tracer(char *buf);
+
+static int __init set_ftrace(char *str)
+{
+ tracing_set_tracer(str);
+ return 1;
+}
+__setup("ftrace", set_ftrace);
+
+static int __init set_ftrace_dump_on_oops(char *str)
+{
+ ftrace_dump_on_oops = 1;
+ return 1;
+}
+__setup("ftrace_dump_on_oops", set_ftrace_dump_on_oops);
long
ns2usecs(cycle_t nsec)
/* tracer_enabled is used to toggle activation of a tracer */
static int tracer_enabled = 1;
+/**
+ * tracing_is_enabled - return tracer_enabled status
+ *
+ * This function is used by other tracers to know the status
+ * of the tracer_enabled flag. Tracers may use this function
+ * to know if it should enable their features when starting
+ * up. See irqsoff tracer for an example (start_irqsoff_tracer).
+ */
+int tracing_is_enabled(void)
+{
+ return tracer_enabled;
+}
+
/* function tracing enabled */
int ftrace_function_enabled;
"stacktrace",
"sched-tree",
"ftrace_printk",
+ "ftrace_preempt",
NULL
};
cmdline_idx = 0;
}
+static int trace_stop_count;
+static DEFINE_SPINLOCK(tracing_start_lock);
+
+/**
+ * tracing_start - quick start of the tracer
+ *
+ * If tracing is enabled but was stopped by tracing_stop,
+ * this will start the tracer back up.
+ */
+void tracing_start(void)
+{
+ struct ring_buffer *buffer;
+ unsigned long flags;
+
+ if (tracing_disabled)
+ return;
+
+ spin_lock_irqsave(&tracing_start_lock, flags);
+ if (--trace_stop_count)
+ goto out;
+
+ if (trace_stop_count < 0) {
+ /* Someone screwed up their debugging */
+ WARN_ON_ONCE(1);
+ trace_stop_count = 0;
+ goto out;
+ }
+
+
+ buffer = global_trace.buffer;
+ if (buffer)
+ ring_buffer_record_enable(buffer);
+
+ buffer = max_tr.buffer;
+ if (buffer)
+ ring_buffer_record_enable(buffer);
+
+ ftrace_start();
+ out:
+ spin_unlock_irqrestore(&tracing_start_lock, flags);
+}
+
+/**
+ * tracing_stop - quick stop of the tracer
+ *
+ * Light weight way to stop tracing. Use in conjunction with
+ * tracing_start.
+ */
+void tracing_stop(void)
+{
+ struct ring_buffer *buffer;
+ unsigned long flags;
+
+ ftrace_stop();
+ spin_lock_irqsave(&tracing_start_lock, flags);
+ if (trace_stop_count++)
+ goto out;
+
+ buffer = global_trace.buffer;
+ if (buffer)
+ ring_buffer_record_disable(buffer);
+
+ buffer = max_tr.buffer;
+ if (buffer)
+ ring_buffer_record_disable(buffer);
+
+ out:
+ spin_unlock_irqrestore(&tracing_start_lock, flags);
+}
+
void trace_stop_cmdline_recording(void);
static void trace_save_cmdline(struct task_struct *tsk)
#ifdef CONFIG_FUNCTION_TRACER
static void
-function_trace_call(unsigned long ip, unsigned long parent_ip)
+function_trace_call_preempt_only(unsigned long ip, unsigned long parent_ip)
{
struct trace_array *tr = &global_trace;
struct trace_array_cpu *data;
return;
pc = preempt_count();
- resched = need_resched();
- preempt_disable_notrace();
+ resched = ftrace_preempt_disable();
local_save_flags(flags);
cpu = raw_smp_processor_id();
data = tr->data[cpu];
trace_function(tr, data, ip, parent_ip, flags, pc);
atomic_dec(&data->disabled);
- if (resched)
- preempt_enable_no_resched_notrace();
- else
- preempt_enable_notrace();
+ ftrace_preempt_enable(resched);
+}
+
+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;
+ int pc;
+
+ if (unlikely(!ftrace_function_enabled))
+ return;
+
+ /*
+ * Need to use raw, since this must be called before the
+ * recursive protection is performed.
+ */
+ raw_local_irq_save(flags);
+ cpu = raw_smp_processor_id();
+ data = tr->data[cpu];
+ disabled = atomic_inc_return(&data->disabled);
+
+ if (likely(disabled == 1)) {
+ pc = preempt_count();
+ trace_function(tr, data, ip, parent_ip, flags, pc);
+ }
+
+ atomic_dec(&data->disabled);
+ raw_local_irq_restore(flags);
}
static struct ftrace_ops trace_ops __read_mostly =
void tracing_start_function_trace(void)
{
ftrace_function_enabled = 0;
+
+ if (trace_flags & TRACE_ITER_PREEMPTONLY)
+ trace_ops.func = function_trace_call_preempt_only;
+ else
+ trace_ops.func = function_trace_call;
+
register_ftrace_function(&trace_ops);
- if (tracer_enabled)
- ftrace_function_enabled = 1;
+ ftrace_function_enabled = 1;
}
void tracing_stop_function_trace(void)
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;
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);
}
m->private = iter;
/* stop the trace while dumping */
- if (iter->tr->ctrl) {
- tracer_enabled = 0;
- ftrace_function_enabled = 0;
- }
+ tracing_stop();
if (iter->trace && iter->trace->open)
iter->trace->open(iter);
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;
- }
+ tracing_start();
mutex_unlock(&trace_types_lock);
seq_release(inode, file);
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);
+ r = sprintf(buf, "%u\n", tracer_enabled);
return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
}
val = !!val;
mutex_lock(&trace_types_lock);
- if (tr->ctrl ^ val) {
- if (val)
+ if (tracer_enabled ^ val) {
+ if (val) {
tracer_enabled = 1;
- else
+ if (current_trace->start)
+ current_trace->start(tr);
+ tracing_start();
+ } else {
tracer_enabled = 0;
-
- tr->ctrl = val;
-
- if (current_trace && current_trace->ctrl_update)
- current_trace->ctrl_update(tr);
+ tracing_stop();
+ if (current_trace->stop)
+ current_trace->stop(tr);
+ }
}
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)
+static int tracing_set_tracer(char *buf)
{
struct trace_array *tr = &global_trace;
struct tracer *t;
- char buf[max_tracer_type_len+1];
- int i;
- size_t ret;
-
- ret = cnt;
-
- 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;
+ int ret = 0;
mutex_lock(&trace_types_lock);
for (t = trace_types; t; t = t->next) {
out:
mutex_unlock(&trace_types_lock);
+ return ret;
+}
+
+static ssize_t
+tracing_set_trace_write(struct file *filp, const char __user *ubuf,
+ size_t cnt, loff_t *ppos)
+{
+ char buf[max_tracer_type_len+1];
+ int i;
+ size_t ret;
+
+ 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;
+
+ ret = tracing_set_tracer(buf);
+ if (!ret)
+ ret = cnt;
+
if (ret > 0)
filp->f_pos += ret;
#ifdef CONFIG_DYNAMIC_FTRACE
+int __weak ftrace_arch_read_dyn_info(char *buf, int size)
+{
+ return 0;
+}
+
static ssize_t
-tracing_read_long(struct file *filp, char __user *ubuf,
+tracing_read_dyn_info(struct file *filp, char __user *ubuf,
size_t cnt, loff_t *ppos)
{
+ static char ftrace_dyn_info_buffer[1024];
+ static DEFINE_MUTEX(dyn_info_mutex);
unsigned long *p = filp->private_data;
- char buf[64];
+ char *buf = ftrace_dyn_info_buffer;
+ int size = ARRAY_SIZE(ftrace_dyn_info_buffer);
int r;
- r = sprintf(buf, "%ld\n", *p);
+ mutex_lock(&dyn_info_mutex);
+ r = sprintf(buf, "%ld ", *p);
- return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
+ r += ftrace_arch_read_dyn_info(buf+r, (size-1)-r);
+ buf[r++] = '\n';
+
+ r = simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
+
+ mutex_unlock(&dyn_info_mutex);
+
+ return r;
}
-static struct file_operations tracing_read_long_fops = {
+static struct file_operations tracing_dyn_info_fops = {
.open = tracing_open_generic,
- .read = tracing_read_long,
+ .read = tracing_read_dyn_info,
};
#endif
#ifdef CONFIG_DYNAMIC_FTRACE
entry = debugfs_create_file("dyn_ftrace_total_info", 0444, d_tracer,
&ftrace_update_tot_cnt,
- &tracing_read_long_fops);
+ &tracing_dyn_info_fops);
if (!entry)
pr_warning("Could not create debugfs "
"'dyn_ftrace_total_info' entry\n");
static int trace_panic_handler(struct notifier_block *this,
unsigned long event, void *unused)
{
- ftrace_dump();
+ if (ftrace_dump_on_oops)
+ ftrace_dump();
return NOTIFY_OK;
}
{
switch (val) {
case DIE_OOPS:
- ftrace_dump();
+ if (ftrace_dump_on_oops)
+ ftrace_dump();
break;
default:
break;
trace_seq_reset(s);
}
-
void ftrace_dump(void)
{
static DEFINE_SPINLOCK(ftrace_dump_lock);
register_tracer(&nop_trace);
#ifdef CONFIG_BOOT_TRACER
+ /* We don't want to launch sched_switch tracer yet */
+ global_trace.ctrl = 0;
register_tracer(&boot_tracer);
current_trace = &boot_tracer;
current_trace->init(&global_trace);
#endif
/* All seems OK, enable tracing */
- global_trace.ctrl = tracer_enabled;
+ global_trace.ctrl = 1;
tracing_disabled = 0;
atomic_notifier_chain_register(&panic_notifier_list,
projects / mv-sheeva.git / blobdiff