1 files changed, 353 insertions, 16 deletions

diff --git a/kernel/trace/trace_functions.c b/kernel/trace/trace_functions.c
index 9236d7e25a16..c9a0b7df44ff 100644
--- a/kernel/trace/trace_functions.c
+++ b/kernel/trace/trace_functions.c
@@ -9,6 +9,7 @@
  *  Copyright (C) 2004-2006 Ingo Molnar
  *  Copyright (C) 2004 William Lee Irwin III
  */
+#include <linux/ring_buffer.h>
 #include <linux/debugfs.h>
 #include <linux/uaccess.h>
 #include <linux/ftrace.h>
@@ -16,52 +17,388 @@
 
 #include "trace.h"
 
-static void start_function_trace(struct trace_array *tr)
+/* function tracing enabled */
+static int			ftrace_function_enabled;
+
+static struct trace_array	*func_trace;
+
+static void tracing_start_function_trace(void);
+static void tracing_stop_function_trace(void);
+
+static int function_trace_init(struct trace_array *tr)
 {
+	func_trace = tr;
 	tr->cpu = get_cpu();
-	tracing_reset_online_cpus(tr);
 	put_cpu();
 
 	tracing_start_cmdline_record();
 	tracing_start_function_trace();
+	return 0;
 }
 
-static void stop_function_trace(struct trace_array *tr)
+static void function_trace_reset(struct trace_array *tr)
 {
 	tracing_stop_function_trace();
 	tracing_stop_cmdline_record();
 }
 
-static int function_trace_init(struct trace_array *tr)
+static void function_trace_start(struct trace_array *tr)
 {
-	start_function_trace(tr);
-	return 0;
+	tracing_reset_online_cpus(tr);
 }
 
-static void function_trace_reset(struct trace_array *tr)
+static void
+function_trace_call_preempt_only(unsigned long ip, unsigned long parent_ip)
+{
+	struct trace_array *tr = func_trace;
+	struct trace_array_cpu *data;
+	unsigned long flags;
+	long disabled;
+	int cpu, resched;
+	int pc;
+
+	if (unlikely(!ftrace_function_enabled))
+		return;
+
+	pc = preempt_count();
+	resched = ftrace_preempt_disable();
+	local_save_flags(flags);
+	cpu = raw_smp_processor_id();
+	data = tr->data[cpu];
+	disabled = atomic_inc_return(&data->disabled);
+
+	if (likely(disabled == 1))
+		trace_function(tr, ip, parent_ip, flags, pc);
+
+	atomic_dec(&data->disabled);
+	ftrace_preempt_enable(resched);
+}
+
+static void
+function_trace_call(unsigned long ip, unsigned long parent_ip)
 {
-	stop_function_trace(tr);
+	struct trace_array *tr = func_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.
+	 */
+	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, ip, parent_ip, flags, pc);
+	}
+
+	atomic_dec(&data->disabled);
+	local_irq_restore(flags);
 }
 
-static void function_trace_start(struct trace_array *tr)
+static void
+function_stack_trace_call(unsigned long ip, unsigned long parent_ip)
 {
-	tracing_reset_online_cpus(tr);
+	struct trace_array *tr = func_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.
+	 */
+	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, ip, parent_ip, flags, pc);
+		/*
+		 * skip over 5 funcs:
+		 *    __ftrace_trace_stack,
+		 *    __trace_stack,
+		 *    function_stack_trace_call
+		 *    ftrace_list_func
+		 *    ftrace_call
+		 */
+		__trace_stack(tr, flags, 5, pc);
+	}
+
+	atomic_dec(&data->disabled);
+	local_irq_restore(flags);
+}
+
+
+static struct ftrace_ops trace_ops __read_mostly =
+{
+	.func = function_trace_call,
+};
+
+static struct ftrace_ops trace_stack_ops __read_mostly =
+{
+	.func = function_stack_trace_call,
+};
+
+/* Our two options */
+enum {
+	TRACE_FUNC_OPT_STACK = 0x1,
+};
+
+static struct tracer_opt func_opts[] = {
+#ifdef CONFIG_STACKTRACE
+	{ TRACER_OPT(func_stack_trace, TRACE_FUNC_OPT_STACK) },
+#endif
+	{ } /* Always set a last empty entry */
+};
+
+static struct tracer_flags func_flags = {
+	.val = 0, /* By default: all flags disabled */
+	.opts = func_opts
+};
+
+static 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;
+
+	if (func_flags.val & TRACE_FUNC_OPT_STACK)
+		register_ftrace_function(&trace_stack_ops);
+	else
+		register_ftrace_function(&trace_ops);
+
+	ftrace_function_enabled = 1;
+}
+
+static void tracing_stop_function_trace(void)
+{
+	ftrace_function_enabled = 0;
+	/* OK if they are not registered */
+	unregister_ftrace_function(&trace_stack_ops);
+	unregister_ftrace_function(&trace_ops);
+}
+
+static int func_set_flag(u32 old_flags, u32 bit, int set)
+{
+	if (bit == TRACE_FUNC_OPT_STACK) {
+		/* do nothing if already set */
+		if (!!set == !!(func_flags.val & TRACE_FUNC_OPT_STACK))
+			return 0;
+
+		if (set) {
+			unregister_ftrace_function(&trace_ops);
+			register_ftrace_function(&trace_stack_ops);
+		} else {
+			unregister_ftrace_function(&trace_stack_ops);
+			register_ftrace_function(&trace_ops);
+		}
+
+		return 0;
+	}
+
+	return -EINVAL;
 }
 
 static struct tracer function_trace __read_mostly =
 {
-	.name	     = "function",
-	.init	     = function_trace_init,
-	.reset	     = function_trace_reset,
-	.start	     = function_trace_start,
+	.name		= "function",
+	.init		= function_trace_init,
+	.reset		= function_trace_reset,
+	.start		= function_trace_start,
+	.wait_pipe	= poll_wait_pipe,
+	.flags		= &func_flags,
+	.set_flag	= func_set_flag,
 #ifdef CONFIG_FTRACE_SELFTEST
-	.selftest    = trace_selftest_startup_function,
+	.selftest	= trace_selftest_startup_function,
 #endif
 };
 
+#ifdef CONFIG_DYNAMIC_FTRACE
+static void
+ftrace_traceon(unsigned long ip, unsigned long parent_ip, void **data)
+{
+	long *count = (long *)data;
+
+	if (tracing_is_on())
+		return;
+
+	if (!*count)
+		return;
+
+	if (*count != -1)
+		(*count)--;
+
+	tracing_on();
+}
+
+static void
+ftrace_traceoff(unsigned long ip, unsigned long parent_ip, void **data)
+{
+	long *count = (long *)data;
+
+	if (!tracing_is_on())
+		return;
+
+	if (!*count)
+		return;
+
+	if (*count != -1)
+		(*count)--;
+
+	tracing_off();
+}
+
+static int
+ftrace_trace_onoff_print(struct seq_file *m, unsigned long ip,
+			 struct ftrace_probe_ops *ops, void *data);
+
+static struct ftrace_probe_ops traceon_probe_ops = {
+	.func			= ftrace_traceon,
+	.print			= ftrace_trace_onoff_print,
+};
+
+static struct ftrace_probe_ops traceoff_probe_ops = {
+	.func			= ftrace_traceoff,
+	.print			= ftrace_trace_onoff_print,
+};
+
+static int
+ftrace_trace_onoff_print(struct seq_file *m, unsigned long ip,
+			 struct ftrace_probe_ops *ops, void *data)
+{
+	char str[KSYM_SYMBOL_LEN];
+	long count = (long)data;
+
+	kallsyms_lookup(ip, NULL, NULL, NULL, str);
+	seq_printf(m, "%s:", str);
+
+	if (ops == &traceon_probe_ops)
+		seq_printf(m, "traceon");
+	else
+		seq_printf(m, "traceoff");
+
+	if (count == -1)
+		seq_printf(m, ":unlimited\n");
+	else
+		seq_printf(m, ":count=%ld", count);
+	seq_putc(m, '\n');
+
+	return 0;
+}
+
+static int
+ftrace_trace_onoff_unreg(char *glob, char *cmd, char *param)
+{
+	struct ftrace_probe_ops *ops;
+
+	/* we register both traceon and traceoff to this callback */
+	if (strcmp(cmd, "traceon") == 0)
+		ops = &traceon_probe_ops;
+	else
+		ops = &traceoff_probe_ops;
+
+	unregister_ftrace_function_probe_func(glob, ops);
+
+	return 0;
+}
+
+static int
+ftrace_trace_onoff_callback(char *glob, char *cmd, char *param, int enable)
+{
+	struct ftrace_probe_ops *ops;
+	void *count = (void *)-1;
+	char *number;
+	int ret;
+
+	/* hash funcs only work with set_ftrace_filter */
+	if (!enable)
+		return -EINVAL;
+
+	if (glob[0] == '!')
+		return ftrace_trace_onoff_unreg(glob+1, cmd, param);
+
+	/* we register both traceon and traceoff to this callback */
+	if (strcmp(cmd, "traceon") == 0)
+		ops = &traceon_probe_ops;
+	else
+		ops = &traceoff_probe_ops;
+
+	if (!param)
+		goto out_reg;
+
+	number = strsep(&param, ":");
+
+	if (!strlen(number))
+		goto out_reg;
+
+	/*
+	 * We use the callback data field (which is a pointer)
+	 * as our counter.
+	 */
+	ret = strict_strtoul(number, 0, (unsigned long *)&count);
+	if (ret)
+		return ret;
+
+ out_reg:
+	ret = register_ftrace_function_probe(glob, ops, count);
+
+	return ret;
+}
+
+static struct ftrace_func_command ftrace_traceon_cmd = {
+	.name			= "traceon",
+	.func			= ftrace_trace_onoff_callback,
+};
+
+static struct ftrace_func_command ftrace_traceoff_cmd = {
+	.name			= "traceoff",
+	.func			= ftrace_trace_onoff_callback,
+};
+
+static int __init init_func_cmd_traceon(void)
+{
+	int ret;
+
+	ret = register_ftrace_command(&ftrace_traceoff_cmd);
+	if (ret)
+		return ret;
+
+	ret = register_ftrace_command(&ftrace_traceon_cmd);
+	if (ret)
+		unregister_ftrace_command(&ftrace_traceoff_cmd);
+	return ret;
+}
+#else
+static inline int init_func_cmd_traceon(void)
+{
+	return 0;
+}
+#endif /* CONFIG_DYNAMIC_FTRACE */
+
 static __init int init_function_trace(void)
 {
+	init_func_cmd_traceon();
 	return register_tracer(&function_trace);
 }
-
 device_initcall(init_function_trace);
+