1 files changed, 100 insertions, 37 deletions

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index d345d649d073..e4c40c868d67 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -34,6 +34,7 @@
 
 #include <linux/stacktrace.h>
 #include <linux/ring_buffer.h>
+#include <linux/irqflags.h>
 
 #include "trace.h"
 
@@ -63,6 +64,37 @@ static cpumask_t __read_mostly		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)
 {
@@ -655,7 +687,11 @@ tracing_generic_entry_update(struct trace_entry *entry, unsigned long flags,
 	entry->preempt_count		= pc & 0xff;
 	entry->pid			= (tsk) ? tsk->pid : 0;
 	entry->flags =
+#ifdef CONFIG_TRACE_IRQFLAGS_SUPPORT
 		(irqs_disabled_flags(flags) ? TRACE_FLAG_IRQS_OFF : 0) |
+#else
+		TRACE_FLAG_IRQS_NOSUPPORT |
+#endif
 		((pc & HARDIRQ_MASK) ? TRACE_FLAG_HARDIRQ : 0) |
 		((pc & SOFTIRQ_MASK) ? TRACE_FLAG_SOFTIRQ : 0) |
 		(need_resched() ? TRACE_FLAG_NEED_RESCHED : 0);
@@ -700,6 +736,7 @@ static void ftrace_trace_stack(struct trace_array *tr,
 			       unsigned long flags,
 			       int skip, int pc)
 {
+#ifdef CONFIG_STACKTRACE
 	struct ring_buffer_event *event;
 	struct stack_entry *entry;
 	struct stack_trace trace;
@@ -725,6 +762,7 @@ static void ftrace_trace_stack(struct trace_array *tr,
 
 	save_stack_trace(&trace);
 	ring_buffer_unlock_commit(tr->buffer, event, irq_flags);
+#endif
 }
 
 void __trace_stack(struct trace_array *tr,
@@ -851,7 +889,7 @@ ftrace_special(unsigned long arg1, unsigned long arg2, unsigned long arg3)
 	preempt_enable_notrace();
 }
 
-#ifdef CONFIG_FTRACE
+#ifdef CONFIG_FUNCTION_TRACER
 static void
 function_trace_call(unsigned long ip, unsigned long parent_ip)
 {
@@ -865,9 +903,6 @@ function_trace_call(unsigned long ip, unsigned long parent_ip)
 	if (unlikely(!ftrace_function_enabled))
 		return;
 
-	if (skip_trace(ip))
-		return;
-
 	pc = preempt_count();
 	resched = need_resched();
 	preempt_disable_notrace();
@@ -1246,7 +1281,8 @@ lat_print_generic(struct trace_seq *s, struct trace_entry *entry, int cpu)
 	trace_seq_printf(s, "%8.8s-%-5d ", comm, entry->pid);
 	trace_seq_printf(s, "%3d", cpu);
 	trace_seq_printf(s, "%c%c",
-			(entry->flags & TRACE_FLAG_IRQS_OFF) ? 'd' : '.',
+			(entry->flags & TRACE_FLAG_IRQS_OFF) ? 'd' :
+			 (entry->flags & TRACE_FLAG_IRQS_NOSUPPORT) ? 'X' : '.',
 			((entry->flags & TRACE_FLAG_NEED_RESCHED) ? 'N' : '.'));
 
 	hardirq = entry->flags & TRACE_FLAG_HARDIRQ;
@@ -2369,28 +2405,11 @@ tracing_set_trace_read(struct file *filp, char __user *ubuf,
 	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;
-
-	if (cnt > max_tracer_type_len)
-		cnt = max_tracer_type_len;
-	ret = cnt;
-
-	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) {
@@ -2414,8 +2433,35 @@ tracing_set_trace_write(struct file *filp, const char __user *ubuf,
  out:
 	mutex_unlock(&trace_types_lock);
 
-	if (ret == cnt)
-		filp->f_pos += cnt;
+	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;
 
 	return ret;
 }
@@ -2816,22 +2862,38 @@ static struct file_operations tracing_mark_fops = {
 
 #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
 
@@ -2940,7 +3002,7 @@ static __init int tracer_init_debugfs(void)
 #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");
@@ -3021,7 +3083,8 @@ EXPORT_SYMBOL_GPL(__ftrace_printk);
 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;
 }
 
@@ -3037,7 +3100,8 @@ static int trace_die_handler(struct notifier_block *self,
 {
 	switch (val) {
 	case DIE_OOPS:
-		ftrace_dump();
+		if (ftrace_dump_on_oops)
+			ftrace_dump();
 		break;
 	default:
 		break;
@@ -3078,7 +3142,6 @@ trace_printk_seq(struct trace_seq *s)
 	trace_seq_reset(s);
 }
 
-
 void ftrace_dump(void)
 {
 	static DEFINE_SPINLOCK(ftrace_dump_lock);
@@ -3097,7 +3160,7 @@ void ftrace_dump(void)
 	dump_ran = 1;
 
 	/* No turning back! */
-	ftrace_kill_atomic();
+	ftrace_kill();
 
 	for_each_tracing_cpu(cpu) {
 		atomic_inc(&global_trace.data[cpu]->disabled);