/* * 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 Nadia Yvette Chambers */#include <linux/ring_buffer.h>#include <linux/debugfs.h>#include <linux/uaccess.h>#include <linux/ftrace.h>#include <linux/slab.h>#include <linux/fs.h> #include "trace.h" static void tracing_start_function_trace(struct trace_array *tr);static void tracing_stop_function_trace(struct trace_array *tr);static voidfunction_trace_call(unsigned long ip, unsigned long parent_ip,		    struct ftrace_ops *op, struct pt_regs *pt_regs);static voidfunction_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; 	ops = kzalloc(sizeof(*ops), GFP_KERNEL);	if (!ops)		return -ENOMEM; 	/* 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;}  int ftrace_create_function_files(struct trace_array *tr,				 struct dentry *parent){	int ret; 	/*	 * The top level array uses the "global_ops", and the files are	 * created on boot up.	 */	if (tr->flags & TRACE_ARRAY_FL_GLOBAL)		return 0; 	ret = allocate_ftrace_ops(tr);	if (ret)		return ret; 	ftrace_create_filter_files(tr->ops, parent); 	return 0;} void ftrace_destroy_function_files(struct trace_array *tr){	ftrace_destroy_filter_files(tr->ops);	kfree(tr->ops);	tr->ops = NULL;} static int function_trace_init(struct trace_array *tr){	struct ftrace_ops *ops; 	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 if (!tr->ops) {		/*		 * Instance trace_arrays get their ops allocated		 * at instance creation. Unless it failed		 * the allocation.		 */		return -ENOMEM;	} 	tr->trace_buffer.cpu = get_cpu();	put_cpu(); 	tracing_start_cmdline_record();	tracing_start_function_trace(tr);	return 0;} static void function_trace_reset(struct trace_array *tr){	tracing_stop_function_trace(tr);	tracing_stop_cmdline_record();} static void function_trace_start(struct trace_array *tr){	tracing_reset_online_cpus(&tr->trace_buffer);} static voidfunction_trace_call(unsigned long ip, unsigned long parent_ip,		    struct ftrace_ops *op, struct pt_regs *pt_regs){	struct trace_array *tr = op->private;	struct trace_array_cpu *data;	unsigned long flags;	int bit;	int cpu;	int pc; 	if (unlikely(!tr->function_enabled))		return; 	pc = preempt_count();	preempt_disable_notrace(); 	bit = trace_test_and_set_recursion(TRACE_FTRACE_START, TRACE_FTRACE_MAX);	if (bit < 0)		goto out; 	cpu = smp_processor_id();	data = per_cpu_ptr(tr->trace_buffer.data, cpu);	if (!atomic_read(&data->disabled)) {		local_save_flags(flags);		trace_function(tr, ip, parent_ip, flags, pc);	}	trace_clear_recursion(bit);  out:	preempt_enable_notrace();} static voidfunction_stack_trace_call(unsigned long ip, unsigned long parent_ip,			  struct ftrace_ops *op, struct pt_regs *pt_regs){	struct trace_array *tr = op->private;	struct trace_array_cpu *data;	unsigned long flags;	long disabled;	int cpu;	int pc; 	if (unlikely(!tr->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 = per_cpu_ptr(tr->trace_buffer.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 | FTRACE_OPS_FL_RECURSION_SAFE,}; static struct ftrace_ops trace_stack_ops __read_mostly ={	.func = function_stack_trace_call,	.flags = FTRACE_OPS_FL_GLOBAL | FTRACE_OPS_FL_RECURSION_SAFE,}; 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(struct trace_array *tr){	tr->function_enabled = 0;	register_ftrace_function(tr->ops);	tr->function_enabled = 1;} static void tracing_stop_function_trace(struct trace_array *tr){	tr->function_enabled = 0;	unregister_ftrace_function(tr->ops);} static intfunc_set_flag(struct trace_array *tr, u32 old_flags, u32 bit, int set){	switch (bit) {	case TRACE_FUNC_OPT_STACK:		/* do nothing if already set */		if (!!set == !!(func_flags.val & TRACE_FUNC_OPT_STACK))			break; 		unregister_ftrace_function(tr->ops); 		if (set) {			tr->ops = &trace_stack_ops;			register_ftrace_function(tr->ops);		} else {			tr->ops = &trace_ops;			register_ftrace_function(tr->ops);		} 		break;	default:		return -EINVAL;	} 	return 0;} static struct tracer function_trace __tracer_data ={	.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,	.allow_instances = true,#ifdef CONFIG_FTRACE_SELFTEST	.selftest	= trace_selftest_startup_function,#endif}; #ifdef CONFIG_DYNAMIC_FTRACEstatic int update_count(void **data){	unsigned long *count = (long *)data; 	if (!*count)		return 0; 	if (*count != -1)		(*count)--; 	return 1;} static voidftrace_traceon_count(unsigned long ip, unsigned long parent_ip, void **data){	if (tracing_is_on())		return; 	if (update_count(data))		tracing_on();} static voidftrace_traceoff_count(unsigned long ip, unsigned long parent_ip, void **data){	if (!tracing_is_on())		return; 	if (update_count(data))		tracing_off();} static voidftrace_traceon(unsigned long ip, unsigned long parent_ip, void **data){	if (tracing_is_on())		return; 	tracing_on();} static voidftrace_traceoff(unsigned long ip, unsigned long parent_ip, void **data){	if (!tracing_is_on())		return; 	tracing_off();} /* * Skip 4: *   ftrace_stacktrace() *   function_trace_probe_call() *   ftrace_ops_list_func() *   ftrace_call() */#define STACK_SKIP 4 static voidftrace_stacktrace(unsigned long ip, unsigned long parent_ip, void **data){	trace_dump_stack(STACK_SKIP);} static voidftrace_stacktrace_count(unsigned long ip, unsigned long parent_ip, void **data){	if (!tracing_is_on())		return; 	if (update_count(data))		trace_dump_stack(STACK_SKIP);} static voidftrace_dump_probe(unsigned long ip, unsigned long parent_ip, void **data){	if (update_count(data))		ftrace_dump(DUMP_ALL);} /* Only dump the current CPU buffer. */static voidftrace_cpudump_probe(unsigned long ip, unsigned long parent_ip, void **data){	if (update_count(data))		ftrace_dump(DUMP_ORIG);} static intftrace_probe_print(const char *name, struct seq_file *m,		   unsigned long ip, void *data){	long count = (long)data; 	seq_printf(m, "%ps:%s", (void *)ip, name); 	if (count == -1)		seq_printf(m, ":unlimited\n");	else		seq_printf(m, ":count=%ld\n", count); 	return 0;} static intftrace_traceon_print(struct seq_file *m, unsigned long ip,			 struct ftrace_probe_ops *ops, void *data){	return ftrace_probe_print("traceon", m, ip, data);} static intftrace_traceoff_print(struct seq_file *m, unsigned long ip,			 struct ftrace_probe_ops *ops, void *data){	return ftrace_probe_print("traceoff", m, ip, data);} static intftrace_stacktrace_print(struct seq_file *m, unsigned long ip,			struct ftrace_probe_ops *ops, void *data){	return ftrace_probe_print("stacktrace", m, ip, data);} static intftrace_dump_print(struct seq_file *m, unsigned long ip,			struct ftrace_probe_ops *ops, void *data){	return ftrace_probe_print("dump", m, ip, data);} static intftrace_cpudump_print(struct seq_file *m, unsigned long ip,			struct ftrace_probe_ops *ops, void *data){	return ftrace_probe_print("cpudump", m, ip, data);} static struct ftrace_probe_ops traceon_count_probe_ops = {	.func			= ftrace_traceon_count,	.print			= ftrace_traceon_print,}; static struct ftrace_probe_ops traceoff_count_probe_ops = {	.func			= ftrace_traceoff_count,	.print			= ftrace_traceoff_print,}; static struct ftrace_probe_ops stacktrace_count_probe_ops = {	.func			= ftrace_stacktrace_count,	.print			= ftrace_stacktrace_print,}; static struct ftrace_probe_ops dump_probe_ops = {	.func			= ftrace_dump_probe,	.print			= ftrace_dump_print,}; static struct ftrace_probe_ops cpudump_probe_ops = {	.func			= ftrace_cpudump_probe,	.print			= ftrace_cpudump_print,}; static struct ftrace_probe_ops traceon_probe_ops = {	.func			= ftrace_traceon,	.print			= ftrace_traceon_print,}; static struct ftrace_probe_ops traceoff_probe_ops = {	.func			= ftrace_traceoff,	.print			= ftrace_traceoff_print,}; static struct ftrace_probe_ops stacktrace_probe_ops = {	.func			= ftrace_stacktrace,	.print			= ftrace_stacktrace_print,}; static intftrace_trace_probe_callback(struct ftrace_probe_ops *ops,			    struct ftrace_hash *hash, char *glob,			    char *cmd, char *param, int enable){	void *count = (void *)-1;	char *number;	int ret; 	/* hash funcs only work with set_ftrace_filter */	if (!enable)		return -EINVAL; 	if (glob[0] == '!') {		unregister_ftrace_function_probe_func(glob+1, ops);		return 0;	} 	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 = kstrtoul(number, 0, (unsigned long *)&count);	if (ret)		return ret;  out_reg:	ret = register_ftrace_function_probe(glob, ops, count); 

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