1 files changed, 92 insertions, 80 deletions

diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 1e6640f80454..6d2cb14f9449 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -22,12 +22,13 @@
 #include <linux/hardirq.h>
 #include <linux/kthread.h>
 #include <linux/uaccess.h>
-#include <linux/kprobes.h>
 #include <linux/ftrace.h>
 #include <linux/sysctl.h>
+#include <linux/slab.h>
 #include <linux/ctype.h>
 #include <linux/list.h>
 #include <linux/hash.h>
+#include <linux/rcupdate.h>
 
 #include <trace/events/sched.h>
 
@@ -85,22 +86,22 @@ ftrace_func_t ftrace_trace_function __read_mostly = ftrace_stub;
 ftrace_func_t __ftrace_trace_function __read_mostly = ftrace_stub;
 ftrace_func_t ftrace_pid_function __read_mostly = ftrace_stub;
 
-#ifdef CONFIG_FUNCTION_GRAPH_TRACER
-static int ftrace_set_func(unsigned long *array, int *idx, char *buffer);
-#endif
-
+/*
+ * Traverse the ftrace_list, invoking all entries.  The reason that we
+ * can use rcu_dereference_raw() is that elements removed from this list
+ * are simply leaked, so there is no need to interact with a grace-period
+ * mechanism.  The rcu_dereference_raw() calls are needed to handle
+ * concurrent insertions into the ftrace_list.
+ *
+ * Silly Alpha and silly pointer-speculation compiler optimizations!
+ */
 static void ftrace_list_func(unsigned long ip, unsigned long parent_ip)
 {
-	struct ftrace_ops *op = ftrace_list;
-
-	/* in case someone actually ports this to alpha! */
-	read_barrier_depends();
+	struct ftrace_ops *op = rcu_dereference_raw(ftrace_list); /*see above*/
 
 	while (op != &ftrace_list_end) {
-		/* silly alpha */
-		read_barrier_depends();
 		op->func(ip, parent_ip);
-		op = op->next;
+		op = rcu_dereference_raw(op->next); /*see above*/
 	};
 }
 
@@ -155,8 +156,7 @@ static int __register_ftrace_function(struct ftrace_ops *ops)
 	 * the ops->next pointer is valid before another CPU sees
 	 * the ops pointer included into the ftrace_list.
 	 */
-	smp_wmb();
-	ftrace_list = ops;
+	rcu_assign_pointer(ftrace_list, ops);
 
 	if (ftrace_enabled) {
 		ftrace_func_t func;
@@ -264,6 +264,7 @@ struct ftrace_profile {
 	unsigned long			counter;
 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 	unsigned long long		time;
+	unsigned long long		time_squared;
 #endif
 };
 
@@ -366,9 +367,9 @@ static int function_stat_headers(struct seq_file *m)
 {
 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 	seq_printf(m, "  Function                               "
-		   "Hit    Time            Avg\n"
+		   "Hit    Time            Avg             s^2\n"
 		      "  --------                               "
-		   "---    ----            ---\n");
+		   "---    ----            ---             ---\n");
 #else
 	seq_printf(m, "  Function                               Hit\n"
 		      "  --------                               ---\n");
@@ -384,6 +385,7 @@ static int function_stat_show(struct seq_file *m, void *v)
 	static DEFINE_MUTEX(mutex);
 	static struct trace_seq s;
 	unsigned long long avg;
+	unsigned long long stddev;
 #endif
 
 	kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
@@ -394,11 +396,25 @@ static int function_stat_show(struct seq_file *m, void *v)
 	avg = rec->time;
 	do_div(avg, rec->counter);
 
+	/* Sample standard deviation (s^2) */
+	if (rec->counter <= 1)
+		stddev = 0;
+	else {
+		stddev = rec->time_squared - rec->counter * avg * avg;
+		/*
+		 * Divide only 1000 for ns^2 -> us^2 conversion.
+		 * trace_print_graph_duration will divide 1000 again.
+		 */
+		do_div(stddev, (rec->counter - 1) * 1000);
+	}
+
 	mutex_lock(&mutex);
 	trace_seq_init(&s);
 	trace_print_graph_duration(rec->time, &s);
 	trace_seq_puts(&s, "    ");
 	trace_print_graph_duration(avg, &s);
+	trace_seq_puts(&s, "    ");
+	trace_print_graph_duration(stddev, &s);
 	trace_print_seq(m, &s);
 	mutex_unlock(&mutex);
 #endif
@@ -650,6 +666,10 @@ static void profile_graph_return(struct ftrace_graph_ret *trace)
 	if (!stat->hash || !ftrace_profile_enabled)
 		goto out;
 
+	/* If the calltime was zero'd ignore it */
+	if (!trace->calltime)
+		goto out;
+
 	calltime = trace->rettime - trace->calltime;
 
 	if (!(trace_flags & TRACE_ITER_GRAPH_TIME)) {
@@ -668,8 +688,10 @@ static void profile_graph_return(struct ftrace_graph_ret *trace)
 	}
 
 	rec = ftrace_find_profiled_func(stat, trace->func);
-	if (rec)
+	if (rec) {
 		rec->time += calltime;
+		rec->time_squared += calltime * calltime;
+	}
 
  out:
 	local_irq_restore(flags);
@@ -898,36 +920,6 @@ static struct dyn_ftrace *ftrace_free_records;
 		}				\
 	}
 
-#ifdef CONFIG_KPROBES
-
-static int frozen_record_count;
-
-static inline void freeze_record(struct dyn_ftrace *rec)
-{
-	if (!(rec->flags & FTRACE_FL_FROZEN)) {
-		rec->flags |= FTRACE_FL_FROZEN;
-		frozen_record_count++;
-	}
-}
-
-static inline void unfreeze_record(struct dyn_ftrace *rec)
-{
-	if (rec->flags & FTRACE_FL_FROZEN) {
-		rec->flags &= ~FTRACE_FL_FROZEN;
-		frozen_record_count--;
-	}
-}
-
-static inline int record_frozen(struct dyn_ftrace *rec)
-{
-	return rec->flags & FTRACE_FL_FROZEN;
-}
-#else
-# define freeze_record(rec)			({ 0; })
-# define unfreeze_record(rec)			({ 0; })
-# define record_frozen(rec)			({ 0; })
-#endif /* CONFIG_KPROBES */
-
 static void ftrace_free_rec(struct dyn_ftrace *rec)
 {
 	rec->freelist = ftrace_free_records;
@@ -1025,6 +1017,21 @@ static void ftrace_bug(int failed, unsigned long ip)
 }
 
 
+/* Return 1 if the address range is reserved for ftrace */
+int ftrace_text_reserved(void *start, void *end)
+{
+	struct dyn_ftrace *rec;
+	struct ftrace_page *pg;
+
+	do_for_each_ftrace_rec(pg, rec) {
+		if (rec->ip <= (unsigned long)end &&
+		    rec->ip + MCOUNT_INSN_SIZE > (unsigned long)start)
+			return 1;
+	} while_for_each_ftrace_rec();
+	return 0;
+}
+
+
 static int
 __ftrace_replace_code(struct dyn_ftrace *rec, int enable)
 {
@@ -1076,14 +1083,6 @@ static void ftrace_replace_code(int enable)
 		    !(rec->flags & FTRACE_FL_CONVERTED))
 			continue;
 
-		/* ignore updates to this record's mcount site */
-		if (get_kprobe((void *)rec->ip)) {
-			freeze_record(rec);
-			continue;
-		} else {
-			unfreeze_record(rec);
-		}
-
 		failed = __ftrace_replace_code(rec, enable);
 		if (failed) {
 			rec->flags |= FTRACE_FL_FAILED;
@@ -2300,6 +2299,8 @@ __setup("ftrace_filter=", set_ftrace_filter);
 
 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 static char ftrace_graph_buf[FTRACE_FILTER_SIZE] __initdata;
+static int ftrace_set_func(unsigned long *array, int *idx, char *buffer);
+
 static int __init set_graph_function(char *str)
 {
 	strlcpy(ftrace_graph_buf, str, FTRACE_FILTER_SIZE);
@@ -2426,6 +2427,7 @@ static const struct file_operations ftrace_notrace_fops = {
 static DEFINE_MUTEX(graph_lock);
 
 int ftrace_graph_count;
+int ftrace_graph_filter_enabled;
 unsigned long ftrace_graph_funcs[FTRACE_GRAPH_MAX_FUNCS] __read_mostly;
 
 static void *
@@ -2448,7 +2450,7 @@ static void *g_start(struct seq_file *m, loff_t *pos)
 	mutex_lock(&graph_lock);
 
 	/* Nothing, tell g_show to print all functions are enabled */
-	if (!ftrace_graph_count && !*pos)
+	if (!ftrace_graph_filter_enabled && !*pos)
 		return (void *)1;
 
 	return __g_next(m, pos);
@@ -2494,6 +2496,7 @@ ftrace_graph_open(struct inode *inode, struct file *file)
 	mutex_lock(&graph_lock);
 	if ((file->f_mode & FMODE_WRITE) &&
 	    (file->f_flags & O_TRUNC)) {
+		ftrace_graph_filter_enabled = 0;
 		ftrace_graph_count = 0;
 		memset(ftrace_graph_funcs, 0, sizeof(ftrace_graph_funcs));
 	}
@@ -2519,7 +2522,7 @@ ftrace_set_func(unsigned long *array, int *idx, char *buffer)
 	struct dyn_ftrace *rec;
 	struct ftrace_page *pg;
 	int search_len;
-	int found = 0;
+	int fail = 1;
 	int type, not;
 	char *search;
 	bool exists;
@@ -2530,37 +2533,51 @@ ftrace_set_func(unsigned long *array, int *idx, char *buffer)
 
 	/* decode regex */
 	type = filter_parse_regex(buffer, strlen(buffer), &search, &not);
-	if (not)
-		return -EINVAL;
+	if (!not && *idx >= FTRACE_GRAPH_MAX_FUNCS)
+		return -EBUSY;
 
 	search_len = strlen(search);
 
 	mutex_lock(&ftrace_lock);
 	do_for_each_ftrace_rec(pg, rec) {
 
-		if (*idx >= FTRACE_GRAPH_MAX_FUNCS)
-			break;
-
 		if (rec->flags & (FTRACE_FL_FAILED | FTRACE_FL_FREE))
 			continue;
 
 		if (ftrace_match_record(rec, search, search_len, type)) {
-			/* ensure it is not already in the array */
+			/* if it is in the array */
 			exists = false;
-			for (i = 0; i < *idx; i++)
+			for (i = 0; i < *idx; i++) {
 				if (array[i] == rec->ip) {
 					exists = true;
 					break;
 				}
-			if (!exists)
-				array[(*idx)++] = rec->ip;
-			found = 1;
+			}
+
+			if (!not) {
+				fail = 0;
+				if (!exists) {
+					array[(*idx)++] = rec->ip;
+					if (*idx >= FTRACE_GRAPH_MAX_FUNCS)
+						goto out;
+				}
+			} else {
+				if (exists) {
+					array[i] = array[--(*idx)];
+					array[*idx] = 0;
+					fail = 0;
+				}
+			}
 		}
 	} while_for_each_ftrace_rec();
-
+out:
 	mutex_unlock(&ftrace_lock);
 
-	return found ? 0 : -EINVAL;
+	if (fail)
+		return -EINVAL;
+
+	ftrace_graph_filter_enabled = 1;
+	return 0;
 }
 
 static ssize_t
@@ -2570,16 +2587,11 @@ ftrace_graph_write(struct file *file, const char __user *ubuf,
 	struct trace_parser parser;
 	ssize_t read, ret;
 
-	if (!cnt || cnt < 0)
+	if (!cnt)
 		return 0;
 
 	mutex_lock(&graph_lock);
 
-	if (ftrace_graph_count >= FTRACE_GRAPH_MAX_FUNCS) {
-		ret = -EBUSY;
-		goto out_unlock;
-	}
-
 	if (trace_parser_get_init(&parser, FTRACE_BUFF_MAX)) {
 		ret = -ENOMEM;
 		goto out_unlock;
@@ -3222,8 +3234,8 @@ free:
 }
 
 static void
-ftrace_graph_probe_sched_switch(struct rq *__rq, struct task_struct *prev,
-				struct task_struct *next)
+ftrace_graph_probe_sched_switch(void *ignore,
+			struct task_struct *prev, struct task_struct *next)
 {
 	unsigned long long timestamp;
 	int index;
@@ -3277,7 +3289,7 @@ static int start_graph_tracing(void)
 	} while (ret == -EAGAIN);
 
 	if (!ret) {
-		ret = register_trace_sched_switch(ftrace_graph_probe_sched_switch);
+		ret = register_trace_sched_switch(ftrace_graph_probe_sched_switch, NULL);
 		if (ret)
 			pr_info("ftrace_graph: Couldn't activate tracepoint"
 				" probe to kernel_sched_switch\n");
@@ -3349,11 +3361,11 @@ void unregister_ftrace_graph(void)
 		goto out;
 
 	ftrace_graph_active--;
-	unregister_trace_sched_switch(ftrace_graph_probe_sched_switch);
 	ftrace_graph_return = (trace_func_graph_ret_t)ftrace_stub;
 	ftrace_graph_entry = ftrace_graph_entry_stub;
 	ftrace_shutdown(FTRACE_STOP_FUNC_RET);
 	unregister_pm_notifier(&ftrace_suspend_notifier);
+	unregister_trace_sched_switch(ftrace_graph_probe_sched_switch, NULL);
 
  out:
 	mutex_unlock(&ftrace_lock);
@@ -3364,6 +3376,7 @@ void ftrace_graph_init_task(struct task_struct *t)
 {
 	/* Make sure we do not use the parent ret_stack */
 	t->ret_stack = NULL;
+	t->curr_ret_stack = -1;
 
 	if (ftrace_graph_active) {
 		struct ftrace_ret_stack *ret_stack;
@@ -3373,7 +3386,6 @@ void ftrace_graph_init_task(struct task_struct *t)
 				GFP_KERNEL);
 		if (!ret_stack)
 			return;
-		t->curr_ret_stack = -1;
 		atomic_set(&t->tracing_graph_pause, 0);
 		atomic_set(&t->trace_overrun, 0);
 		t->ftrace_timestamp = 0;