/* * ring buffer based function tracer * * Copyright (C) 2007-2008 Steven Rostedt <srostedt@redhat.com> * Copyright (C) 2008 Ingo Molnar <mingo@redhat.com> * * Based on code from the latency_tracer, that is: * *  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>#include <linux/fs.h> #include "trace.h" /* 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();	put_cpu(); 	tracing_start_cmdline_record();	tracing_start_function_trace();	return 0;} static void function_trace_reset(struct trace_array *tr){	tracing_stop_function_trace();	tracing_stop_cmdline_record();} static void function_trace_start(struct trace_array *tr){	tracing_reset_online_cpus(tr);} static voidfunction_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;	int pc; 	if (unlikely(!ftrace_function_enabled))		return; 	pc = preempt_count();	preempt_disable_notrace();	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);	preempt_enable_notrace();} static voidfunction_trace_call(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;	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 voidfunction_stack_trace_call(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;	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,	.flags = FTRACE_OPS_FL_GLOBAL,}; static struct ftrace_ops trace_stack_ops __read_mostly ={	.func = function_stack_trace_call,	.flags = FTRACE_OPS_FL_GLOBAL,}; /* 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; 	if (func_flags.val & TRACE_FUNC_OPT_STACK)		unregister_ftrace_function(&trace_stack_ops);	else		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,	.wait_pipe	= poll_wait_pipe,	.flags		= &func_flags,	.set_flag	= func_set_flag,#ifdef CONFIG_FTRACE_SELFTEST	.selftest	= trace_selftest_startup_function,#endif}; #ifdef CONFIG_DYNAMIC_FTRACEstatic voidftrace_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 voidftrace_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 intftrace_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 intftrace_trace_onoff_print(struct seq_file *m, unsigned long ip,			 struct ftrace_probe_ops *ops, void *data){	long count = (long)data; 	seq_printf(m, "%ps:", (void *)ip); 	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\n", count); 	return 0;} static intftrace_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 intftrace_trace_onoff_callback(struct ftrace_hash *hash,			    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 < 0 ? ret : 0;} 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;}#elsestatic 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);