1 files changed, 76 insertions, 40 deletions

diff --git a/kernel/trace/trace_functions.c b/kernel/trace/trace_functions.c
index 85e517e84f50..3f8dc1ce8b9c 100644
--- a/kernel/trace/trace_functions.c
+++ b/kernel/trace/trace_functions.c
@@ -13,33 +13,83 @@
 #include <linux/debugfs.h>
 #include <linux/uaccess.h>
 #include <linux/ftrace.h>
+#include <linux/slab.h>
 #include <linux/fs.h>
 
 #include "trace.h"
 
-/* function tracing enabled */
-static int			ftrace_function_enabled;
+static void tracing_start_function_trace(struct trace_array *tr);
+static void tracing_stop_function_trace(struct trace_array *tr);
+static void
+function_trace_call(unsigned long ip, unsigned long parent_ip,
+		    struct ftrace_ops *op, struct pt_regs *pt_regs);
+static void
+function_stack_trace_call(unsigned long ip, unsigned long parent_ip,
+			  struct ftrace_ops *op, struct pt_regs *pt_regs);
+static struct ftrace_ops trace_ops;
+static struct ftrace_ops trace_stack_ops;
+static struct tracer_flags func_flags;
+
+/* Our option */
+enum {
+	TRACE_FUNC_OPT_STACK	= 0x1,
+};
+
+static int allocate_ftrace_ops(struct trace_array *tr)
+{
+	struct ftrace_ops *ops;
 
-static struct trace_array	*func_trace;
+	ops = kzalloc(sizeof(*ops), GFP_KERNEL);
+	if (!ops)
+		return -ENOMEM;
 
-static void tracing_start_function_trace(void);
-static void tracing_stop_function_trace(void);
+	/* Currently only the non stack verision is supported */
+	ops->func = function_trace_call;
+	ops->flags = FTRACE_OPS_FL_RECURSION_SAFE;
+
+	tr->ops = ops;
+	ops->private = tr;
+	return 0;
+}
 
 static int function_trace_init(struct trace_array *tr)
 {
-	func_trace = tr;
+	struct ftrace_ops *ops;
+	int ret;
+
+	if (tr->flags & TRACE_ARRAY_FL_GLOBAL) {
+		/* There's only one global tr */
+		if (!trace_ops.private) {
+			trace_ops.private = tr;
+			trace_stack_ops.private = tr;
+		}
+
+		if (func_flags.val & TRACE_FUNC_OPT_STACK)
+			ops = &trace_stack_ops;
+		else
+			ops = &trace_ops;
+		tr->ops = ops;
+	} else {
+		ret = allocate_ftrace_ops(tr);
+		if (ret)
+			return ret;
+	}
+
 	tr->trace_buffer.cpu = get_cpu();
 	put_cpu();
 
 	tracing_start_cmdline_record();
-	tracing_start_function_trace();
+	tracing_start_function_trace(tr);
 	return 0;
 }
 
 static void function_trace_reset(struct trace_array *tr)
 {
-	tracing_stop_function_trace();
+	tracing_stop_function_trace(tr);
 	tracing_stop_cmdline_record();
+	if (!(tr->flags & TRACE_ARRAY_FL_GLOBAL))
+		kfree(tr->ops);
+	tr->ops = NULL;
 }
 
 static void function_trace_start(struct trace_array *tr)
@@ -47,25 +97,18 @@ static void function_trace_start(struct trace_array *tr)
 	tracing_reset_online_cpus(&tr->trace_buffer);
 }
 
-/* Our option */
-enum {
-	TRACE_FUNC_OPT_STACK	= 0x1,
-};
-
-static struct tracer_flags func_flags;
-
 static void
 function_trace_call(unsigned long ip, unsigned long parent_ip,
 		    struct ftrace_ops *op, struct pt_regs *pt_regs)
 {
-	struct trace_array *tr = func_trace;
+	struct trace_array *tr = op->private;
 	struct trace_array_cpu *data;
 	unsigned long flags;
 	int bit;
 	int cpu;
 	int pc;
 
-	if (unlikely(!ftrace_function_enabled))
+	if (unlikely(!tr->function_enabled))
 		return;
 
 	pc = preempt_count();
@@ -91,14 +134,14 @@ static void
 function_stack_trace_call(unsigned long ip, unsigned long parent_ip,
 			  struct ftrace_ops *op, struct pt_regs *pt_regs)
 {
-	struct trace_array *tr = func_trace;
+	struct trace_array *tr = op->private;
 	struct trace_array_cpu *data;
 	unsigned long flags;
 	long disabled;
 	int cpu;
 	int pc;
 
-	if (unlikely(!ftrace_function_enabled))
+	if (unlikely(!tr->function_enabled))
 		return;
 
 	/*
@@ -128,7 +171,6 @@ function_stack_trace_call(unsigned long ip, unsigned long parent_ip,
 	local_irq_restore(flags);
 }
 
-
 static struct ftrace_ops trace_ops __read_mostly =
 {
 	.func = function_trace_call,
@@ -153,26 +195,17 @@ static struct tracer_flags func_flags = {
 	.opts = func_opts
 };
 
-static void tracing_start_function_trace(void)
+static void tracing_start_function_trace(struct trace_array *tr)
 {
-	ftrace_function_enabled = 0;
-
-	if (func_flags.val & TRACE_FUNC_OPT_STACK)
-		register_ftrace_function(&trace_stack_ops);
-	else
-		register_ftrace_function(&trace_ops);
-
-	ftrace_function_enabled = 1;
+	tr->function_enabled = 0;
+	register_ftrace_function(tr->ops);
+	tr->function_enabled = 1;
 }
 
-static void tracing_stop_function_trace(void)
+static void tracing_stop_function_trace(struct trace_array *tr)
 {
-	ftrace_function_enabled = 0;
-
-	if (func_flags.val & TRACE_FUNC_OPT_STACK)
-		unregister_ftrace_function(&trace_stack_ops);
-	else
-		unregister_ftrace_function(&trace_ops);
+	tr->function_enabled = 0;
+	unregister_ftrace_function(tr->ops);
 }
 
 static int
@@ -184,12 +217,14 @@ func_set_flag(struct trace_array *tr, u32 old_flags, u32 bit, int set)
 		if (!!set == !!(func_flags.val & TRACE_FUNC_OPT_STACK))
 			break;
 
+		unregister_ftrace_function(tr->ops);
+
 		if (set) {
-			unregister_ftrace_function(&trace_ops);
-			register_ftrace_function(&trace_stack_ops);
+			tr->ops = &trace_stack_ops;
+			register_ftrace_function(tr->ops);
 		} else {
-			unregister_ftrace_function(&trace_stack_ops);
-			register_ftrace_function(&trace_ops);
+			tr->ops = &trace_ops;
+			register_ftrace_function(tr->ops);
 		}
 
 		break;
@@ -209,6 +244,7 @@ static struct tracer function_trace __tracer_data =
 	.wait_pipe	= poll_wait_pipe,
 	.flags		= &func_flags,
 	.set_flag	= func_set_flag,
+	.allow_instances = true,
 #ifdef CONFIG_FTRACE_SELFTEST
 	.selftest	= trace_selftest_startup_function,
 #endif