[net-next-2.6.git] / kernel / trace / trace.h

#ifndef _LINUX_KERNEL_TRACE_H
#define _LINUX_KERNEL_TRACE_H

#include <linux/fs.h>
#include <asm/atomic.h>
#include <linux/sched.h>
#include <linux/clocksource.h>
#include <linux/ring_buffer.h>
#include <linux/mmiotrace.h>
#include <linux/ftrace.h>

enum trace_type {
	__TRACE_FIRST_TYPE = 0,

	TRACE_FN,
	TRACE_CTX,
	TRACE_WAKE,
	TRACE_CONT,
	TRACE_STACK,
	TRACE_PRINT,
	TRACE_SPECIAL,
	TRACE_MMIO_RW,
	TRACE_MMIO_MAP,
	TRACE_BOOT,

	__TRACE_LAST_TYPE
};

/*
 * The trace entry - the most basic unit of tracing. This is what
 * is printed in the end as a single line in the trace output, such as:
 *
 *     bash-15816 [01]   235.197585: idle_cpu <- irq_enter
 */
struct trace_entry {
	unsigned char		type;
	unsigned char		cpu;
	unsigned char		flags;
	unsigned char		preempt_count;
	int			pid;
};

/*
 * Function trace entry - function address and parent function addres:
 */
struct ftrace_entry {
	struct trace_entry	ent;
	unsigned long		ip;
	unsigned long		parent_ip;
};
extern struct tracer boot_tracer;
extern struct tracer sched_switch_trace; /* Used by the boot tracer */

/*
 * Context switch trace entry - which task (and prio) we switched from/to:
 */
struct ctx_switch_entry {
	struct trace_entry	ent;
	unsigned int		prev_pid;
	unsigned char		prev_prio;
	unsigned char		prev_state;
	unsigned int		next_pid;
	unsigned char		next_prio;
	unsigned char		next_state;
	unsigned int		next_cpu;
};

/*
 * Special (free-form) trace entry:
 */
struct special_entry {
	struct trace_entry	ent;
	unsigned long		arg1;
	unsigned long		arg2;
	unsigned long		arg3;
};

/*
 * Stack-trace entry:
 */

#define FTRACE_STACK_ENTRIES	8

struct stack_entry {
	struct trace_entry	ent;
	unsigned long		caller[FTRACE_STACK_ENTRIES];
};

/*
 * ftrace_printk entry:
 */
struct print_entry {
	struct trace_entry	ent;
	unsigned long		ip;
	char			buf[];
};

#define TRACE_OLD_SIZE		88

struct trace_field_cont {
	unsigned char		type;
	/* Temporary till we get rid of this completely */
	char			buf[TRACE_OLD_SIZE - 1];
};

struct trace_mmiotrace_rw {
	struct trace_entry	ent;
	struct mmiotrace_rw	rw;
};

struct trace_mmiotrace_map {
	struct trace_entry	ent;
	struct mmiotrace_map	map;
};

struct trace_boot {
	struct trace_entry	ent;
	struct boot_trace	initcall;
};

/*
 * trace_flag_type is an enumeration that holds different
 * states when a trace occurs. These are:
 *  IRQS_OFF		- interrupts were disabled
 *  IRQS_NOSUPPORT 	- arch does not support irqs_disabled_flags
 *  NEED_RESCED		- reschedule is requested
 *  HARDIRQ		- inside an interrupt handler
 *  SOFTIRQ		- inside a softirq handler
 *  CONT		- multiple entries hold the trace item
 */
enum trace_flag_type {
	TRACE_FLAG_IRQS_OFF		= 0x01,
	TRACE_FLAG_IRQS_NOSUPPORT	= 0x02,
	TRACE_FLAG_NEED_RESCHED		= 0x04,
	TRACE_FLAG_HARDIRQ		= 0x08,
	TRACE_FLAG_SOFTIRQ		= 0x10,
	TRACE_FLAG_CONT			= 0x20,
};

#define TRACE_BUF_SIZE		1024

/*
 * The CPU trace array - it consists of thousands of trace entries
 * plus some other descriptor data: (for example which task started
 * the trace, etc.)
 */
struct trace_array_cpu {
	atomic_t		disabled;

	/* these fields get copied into max-trace: */
	unsigned long		trace_idx;
	unsigned long		overrun;
	unsigned long		saved_latency;
	unsigned long		critical_start;
	unsigned long		critical_end;
	unsigned long		critical_sequence;
	unsigned long		nice;
	unsigned long		policy;
	unsigned long		rt_priority;
	cycle_t			preempt_timestamp;
	pid_t			pid;
	uid_t			uid;
	char			comm[TASK_COMM_LEN];
};

struct trace_iterator;

/*
 * The trace array - an array of per-CPU trace arrays. This is the
 * highest level data structure that individual tracers deal with.
 * They have on/off state as well:
 */
struct trace_array {
	struct ring_buffer	*buffer;
	unsigned long		entries;
	long			ctrl;
	int			cpu;
	cycle_t			time_start;
	struct task_struct	*waiter;
	struct trace_array_cpu	*data[NR_CPUS];
};

#define FTRACE_CMP_TYPE(var, type) \
	__builtin_types_compatible_p(typeof(var), type *)

#undef IF_ASSIGN
#define IF_ASSIGN(var, entry, etype, id)		\
	if (FTRACE_CMP_TYPE(var, etype)) {		\
		var = (typeof(var))(entry);		\
		WARN_ON(id && (entry)->type != id);	\
		break;					\
	}

/* Will cause compile errors if type is not found. */
extern void __ftrace_bad_type(void);

/*
 * The trace_assign_type is a verifier that the entry type is
 * the same as the type being assigned. To add new types simply
 * add a line with the following format:
 *
 * IF_ASSIGN(var, ent, type, id);
 *
 *  Where "type" is the trace type that includes the trace_entry
 *  as the "ent" item. And "id" is the trace identifier that is
 *  used in the trace_type enum.
 *
 *  If the type can have more than one id, then use zero.
 */
#define trace_assign_type(var, ent)					\
	do {								\
		IF_ASSIGN(var, ent, struct ftrace_entry, TRACE_FN);	\
		IF_ASSIGN(var, ent, struct ctx_switch_entry, 0);	\
		IF_ASSIGN(var, ent, struct trace_field_cont, TRACE_CONT); \
		IF_ASSIGN(var, ent, struct stack_entry, TRACE_STACK);	\
		IF_ASSIGN(var, ent, struct print_entry, TRACE_PRINT);	\
		IF_ASSIGN(var, ent, struct special_entry, 0);		\
		IF_ASSIGN(var, ent, struct trace_mmiotrace_rw,		\
			  TRACE_MMIO_RW);				\
		IF_ASSIGN(var, ent, struct trace_mmiotrace_map,		\
			  TRACE_MMIO_MAP);				\
		IF_ASSIGN(var, ent, struct trace_boot, TRACE_BOOT);	\
		__ftrace_bad_type();					\
	} while (0)

/* Return values for print_line callback */
enum print_line_t {
	TRACE_TYPE_PARTIAL_LINE	= 0,	/* Retry after flushing the seq */
	TRACE_TYPE_HANDLED	= 1,
	TRACE_TYPE_UNHANDLED	= 2	/* Relay to other output functions */
};

/*
 * A specific tracer, represented by methods that operate on a trace array:
 */
struct tracer {
	const char		*name;
	void			(*init)(struct trace_array *tr);
	void			(*reset)(struct trace_array *tr);
	void			(*open)(struct trace_iterator *iter);
	void			(*pipe_open)(struct trace_iterator *iter);
	void			(*close)(struct trace_iterator *iter);
	void			(*start)(struct trace_iterator *iter);
	void			(*stop)(struct trace_iterator *iter);
	ssize_t			(*read)(struct trace_iterator *iter,
					struct file *filp, char __user *ubuf,
					size_t cnt, loff_t *ppos);
	void			(*ctrl_update)(struct trace_array *tr);
#ifdef CONFIG_FTRACE_STARTUP_TEST
	int			(*selftest)(struct tracer *trace,
					    struct trace_array *tr);
#endif
	enum print_line_t	(*print_line)(struct trace_iterator *iter);
	struct tracer		*next;
	int			print_max;
};

struct trace_seq {
	unsigned char		buffer[PAGE_SIZE];
	unsigned int		len;
	unsigned int		readpos;
};

/*
 * Trace iterator - used by printout routines who present trace
 * results to users and which routines might sleep, etc:
 */
struct trace_iterator {
	struct trace_array	*tr;
	struct tracer		*trace;
	void			*private;
	struct ring_buffer_iter	*buffer_iter[NR_CPUS];

	/* The below is zeroed out in pipe_read */
	struct trace_seq	seq;
	struct trace_entry	*ent;
	int			cpu;
	u64			ts;

	unsigned long		iter_flags;
	loff_t			pos;
	long			idx;
};

void trace_wake_up(void);
void tracing_reset(struct trace_array *tr, int cpu);
int tracing_open_generic(struct inode *inode, struct file *filp);
struct dentry *tracing_init_dentry(void);
void init_tracer_sysprof_debugfs(struct dentry *d_tracer);

struct trace_entry *tracing_get_trace_entry(struct trace_array *tr,
						struct trace_array_cpu *data);
void tracing_generic_entry_update(struct trace_entry *entry,
				  unsigned long flags,
				  int pc);

void ftrace(struct trace_array *tr,
			    struct trace_array_cpu *data,
			    unsigned long ip,
			    unsigned long parent_ip,
			    unsigned long flags, int pc);
void tracing_sched_switch_trace(struct trace_array *tr,
				struct trace_array_cpu *data,
				struct task_struct *prev,
				struct task_struct *next,
				unsigned long flags, int pc);
void tracing_record_cmdline(struct task_struct *tsk);

void tracing_sched_wakeup_trace(struct trace_array *tr,
				struct trace_array_cpu *data,
				struct task_struct *wakee,
				struct task_struct *cur,
				unsigned long flags, int pc);
void trace_special(struct trace_array *tr,
		   struct trace_array_cpu *data,
		   unsigned long arg1,
		   unsigned long arg2,
		   unsigned long arg3, int pc);
void trace_function(struct trace_array *tr,
		    struct trace_array_cpu *data,
		    unsigned long ip,
		    unsigned long parent_ip,
		    unsigned long flags, int pc);

void tracing_start_cmdline_record(void);
void tracing_stop_cmdline_record(void);
int register_tracer(struct tracer *type);
void unregister_tracer(struct tracer *type);

extern unsigned long nsecs_to_usecs(unsigned long nsecs);

extern unsigned long tracing_max_latency;
extern unsigned long tracing_thresh;

void update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu);
void update_max_tr_single(struct trace_array *tr,
			  struct task_struct *tsk, int cpu);

extern cycle_t ftrace_now(int cpu);

#ifdef CONFIG_FUNCTION_TRACER
void tracing_start_function_trace(void);
void tracing_stop_function_trace(void);
#else
# define tracing_start_function_trace()		do { } while (0)
# define tracing_stop_function_trace()		do { } while (0)
#endif

#ifdef CONFIG_CONTEXT_SWITCH_TRACER
typedef void
(*tracer_switch_func_t)(void *private,
			void *__rq,
			struct task_struct *prev,
			struct task_struct *next);

struct tracer_switch_ops {
	tracer_switch_func_t		func;
	void				*private;
	struct tracer_switch_ops	*next;
};

#endif /* CONFIG_CONTEXT_SWITCH_TRACER */

#ifdef CONFIG_DYNAMIC_FTRACE
extern unsigned long ftrace_update_tot_cnt;
#define DYN_FTRACE_TEST_NAME trace_selftest_dynamic_test_func
extern int DYN_FTRACE_TEST_NAME(void);
#endif

#ifdef CONFIG_FTRACE_STARTUP_TEST
extern int trace_selftest_startup_function(struct tracer *trace,
					   struct trace_array *tr);
extern int trace_selftest_startup_irqsoff(struct tracer *trace,
					  struct trace_array *tr);
extern int trace_selftest_startup_preemptoff(struct tracer *trace,
					     struct trace_array *tr);
extern int trace_selftest_startup_preemptirqsoff(struct tracer *trace,
						 struct trace_array *tr);
extern int trace_selftest_startup_wakeup(struct tracer *trace,
					 struct trace_array *tr);
extern int trace_selftest_startup_nop(struct tracer *trace,
					 struct trace_array *tr);
extern int trace_selftest_startup_sched_switch(struct tracer *trace,
					       struct trace_array *tr);
extern int trace_selftest_startup_sysprof(struct tracer *trace,
					       struct trace_array *tr);
#endif /* CONFIG_FTRACE_STARTUP_TEST */

extern void *head_page(struct trace_array_cpu *data);
extern int trace_seq_printf(struct trace_seq *s, const char *fmt, ...);
extern void trace_seq_print_cont(struct trace_seq *s,
				 struct trace_iterator *iter);
extern ssize_t trace_seq_to_user(struct trace_seq *s, char __user *ubuf,
				 size_t cnt);
extern long ns2usecs(cycle_t nsec);
extern int trace_vprintk(unsigned long ip, const char *fmt, va_list args);

extern unsigned long trace_flags;

/*
 * trace_iterator_flags is an enumeration that defines bit
 * positions into trace_flags that controls the output.
 *
 * NOTE: These bits must match the trace_options array in
 *       trace.c.
 */
enum trace_iterator_flags {
	TRACE_ITER_PRINT_PARENT		= 0x01,
	TRACE_ITER_SYM_OFFSET		= 0x02,
	TRACE_ITER_SYM_ADDR		= 0x04,
	TRACE_ITER_VERBOSE		= 0x08,
	TRACE_ITER_RAW			= 0x10,
	TRACE_ITER_HEX			= 0x20,
	TRACE_ITER_BIN			= 0x40,
	TRACE_ITER_BLOCK		= 0x80,
	TRACE_ITER_STACKTRACE		= 0x100,
	TRACE_ITER_SCHED_TREE		= 0x200,
	TRACE_ITER_PRINTK		= 0x400,
	TRACE_ITER_PREEMPTONLY		= 0x800,
};

extern struct tracer nop_trace;

/**
 * ftrace_preempt_disable - disable preemption scheduler safe
 *
 * When tracing can happen inside the scheduler, there exists
 * cases that the tracing might happen before the need_resched
 * flag is checked. If this happens and the tracer calls
 * preempt_enable (after a disable), a schedule might take place
 * causing an infinite recursion.
 *
 * To prevent this, we read the need_recshed flag before
 * disabling preemption. When we want to enable preemption we
 * check the flag, if it is set, then we call preempt_enable_no_resched.
 * Otherwise, we call preempt_enable.
 *
 * The rational for doing the above is that if need resched is set
 * and we have yet to reschedule, we are either in an atomic location
 * (where we do not need to check for scheduling) or we are inside
 * the scheduler and do not want to resched.
 */
static inline int ftrace_preempt_disable(void)
{
	int resched;

	resched = need_resched();
	preempt_disable_notrace();

	return resched;
}

/**
 * ftrace_preempt_enable - enable preemption scheduler safe
 * @resched: the return value from ftrace_preempt_disable
 *
 * This is a scheduler safe way to enable preemption and not miss
 * any preemption checks. The disabled saved the state of preemption.
 * If resched is set, then we were either inside an atomic or
 * are inside the scheduler (we would have already scheduled
 * otherwise). In this case, we do not want to call normal
 * preempt_enable, but preempt_enable_no_resched instead.
 */
static inline void ftrace_preempt_enable(int resched)
{
	if (resched)
		preempt_enable_no_resched_notrace();
	else
		preempt_enable_notrace();
}

#endif /* _LINUX_KERNEL_TRACE_H */
Commit	Line	Data
bc0c38d1 SR	1	#ifndef _LINUX_KERNEL_TRACE_H
	2	#define _LINUX_KERNEL_TRACE_H
	3
	4	#include <linux/fs.h>
	5	#include <asm/atomic.h>
	6	#include <linux/sched.h>
	7	#include <linux/clocksource.h>
3928a8a2	8	#include <linux/ring_buffer.h>
bd8ac686	9	#include <linux/mmiotrace.h>
d13744cd	10	#include <linux/ftrace.h>
bc0c38d1	11
72829bc3 TG	12	enum trace_type {
	13	__TRACE_FIRST_TYPE = 0,
	14
	15	TRACE_FN,
	16	TRACE_CTX,
	17	TRACE_WAKE,
dd0e545f	18	TRACE_CONT,
72829bc3	19	TRACE_STACK,
dd0e545f	20	TRACE_PRINT,
72829bc3	21	TRACE_SPECIAL,
bd8ac686 PP	22	TRACE_MMIO_RW,
bd8ac686 PP	23	TRACE_MMIO_MAP,
d13744cd	24	TRACE_BOOT,
72829bc3 TG	25
	26	__TRACE_LAST_TYPE
	27	};
	28
777e208d SR	29	/*
	30	* The trace entry - the most basic unit of tracing. This is what
	31	* is printed in the end as a single line in the trace output, such as:
	32	*
	33	* bash-15816 [01] 235.197585: idle_cpu <- irq_enter
	34	*/
	35	struct trace_entry {
	36	unsigned char type;
	37	unsigned char cpu;
	38	unsigned char flags;
	39	unsigned char preempt_count;
	40	int pid;
	41	};
	42
bc0c38d1 SR	43	/*
	44	* Function trace entry - function address and parent function addres:
	45	*/
	46	struct ftrace_entry {
777e208d	47	struct trace_entry ent;
bc0c38d1 SR	48	unsigned long ip;
	49	unsigned long parent_ip;
	50	};
d13744cd	51	extern struct tracer boot_tracer;
d7ad44b6	52	extern struct tracer sched_switch_trace; /* Used by the boot tracer */
bc0c38d1 SR	53
	54	/*
	55	* Context switch trace entry - which task (and prio) we switched from/to:
	56	*/
	57	struct ctx_switch_entry {
777e208d	58	struct trace_entry ent;
bc0c38d1 SR	59	unsigned int prev_pid;
	60	unsigned char prev_prio;
	61	unsigned char prev_state;
	62	unsigned int next_pid;
	63	unsigned char next_prio;
bac524d3	64	unsigned char next_state;
80b5e940	65	unsigned int next_cpu;
bc0c38d1 SR	66	};
bc0c38d1 SR	67
f0a920d5 IM	68	/*
	69	* Special (free-form) trace entry:
	70	*/
	71	struct special_entry {
777e208d	72	struct trace_entry ent;
f0a920d5 IM	73	unsigned long arg1;
	74	unsigned long arg2;
	75	unsigned long arg3;
	76	};
	77
86387f7e IM	78	/*
	79	* Stack-trace entry:
	80	*/
	81
74f4e369	82	#define FTRACE_STACK_ENTRIES 8
86387f7e IM	83
86387f7e IM	84	struct stack_entry {
777e208d	85	struct trace_entry ent;
86387f7e IM	86	unsigned long caller[FTRACE_STACK_ENTRIES];
	87	};
	88
dd0e545f SR	89	/*
	90	* ftrace_printk entry:
	91	*/
	92	struct print_entry {
777e208d	93	struct trace_entry ent;
dd0e545f SR	94	unsigned long ip;
	95	char buf[];
	96	};
	97
777e208d SR	98	#define TRACE_OLD_SIZE 88
	99
	100	struct trace_field_cont {
	101	unsigned char type;
	102	/* Temporary till we get rid of this completely */
	103	char buf[TRACE_OLD_SIZE - 1];
	104	};
	105
	106	struct trace_mmiotrace_rw {
	107	struct trace_entry ent;
	108	struct mmiotrace_rw rw;
	109	};
	110
	111	struct trace_mmiotrace_map {
	112	struct trace_entry ent;
	113	struct mmiotrace_map map;
	114	};
	115
	116	struct trace_boot {
	117	struct trace_entry ent;
	118	struct boot_trace initcall;
	119	};
	120
fc5e27ae PP	121	/*
	122	* trace_flag_type is an enumeration that holds different
	123	* states when a trace occurs. These are:
9244489a SR	124	* IRQS_OFF - interrupts were disabled
	125	* IRQS_NOSUPPORT - arch does not support irqs_disabled_flags
	126	* NEED_RESCED - reschedule is requested
	127	* HARDIRQ - inside an interrupt handler
	128	* SOFTIRQ - inside a softirq handler
	129	* CONT - multiple entries hold the trace item
fc5e27ae PP	130	*/
	131	enum trace_flag_type {
	132	TRACE_FLAG_IRQS_OFF = 0x01,
9244489a SR	133	TRACE_FLAG_IRQS_NOSUPPORT = 0x02,
	134	TRACE_FLAG_NEED_RESCHED = 0x04,
	135	TRACE_FLAG_HARDIRQ = 0x08,
	136	TRACE_FLAG_SOFTIRQ = 0x10,
	137	TRACE_FLAG_CONT = 0x20,
fc5e27ae PP	138	};
fc5e27ae PP	139
5bf9a1ee	140	#define TRACE_BUF_SIZE 1024
bc0c38d1 SR	141
	142	/*
	143	* The CPU trace array - it consists of thousands of trace entries
	144	* plus some other descriptor data: (for example which task started
	145	* the trace, etc.)
	146	*/
	147	struct trace_array_cpu {
bc0c38d1	148	atomic_t disabled;
4e3c3333	149
c7aafc54	150	/* these fields get copied into max-trace: */
c7aafc54	151	unsigned long trace_idx;
53d0aa77	152	unsigned long overrun;
bc0c38d1 SR	153	unsigned long saved_latency;
	154	unsigned long critical_start;
	155	unsigned long critical_end;
	156	unsigned long critical_sequence;
	157	unsigned long nice;
	158	unsigned long policy;
	159	unsigned long rt_priority;
	160	cycle_t preempt_timestamp;
	161	pid_t pid;
	162	uid_t uid;
	163	char comm[TASK_COMM_LEN];
	164	};
	165
	166	struct trace_iterator;
	167
	168	/*
	169	* The trace array - an array of per-CPU trace arrays. This is the
	170	* highest level data structure that individual tracers deal with.
	171	* They have on/off state as well:
	172	*/
	173	struct trace_array {
3928a8a2	174	struct ring_buffer *buffer;
bc0c38d1 SR	175	unsigned long entries;
	176	long ctrl;
	177	int cpu;
	178	cycle_t time_start;
b3806b43	179	struct task_struct *waiter;
bc0c38d1 SR	180	struct trace_array_cpu *data[NR_CPUS];
	181	};
	182
7104f300 SR	183	#define FTRACE_CMP_TYPE(var, type) \
	184	__builtin_types_compatible_p(typeof(var), type *)
	185
	186	#undef IF_ASSIGN
	187	#define IF_ASSIGN(var, entry, etype, id) \
	188	if (FTRACE_CMP_TYPE(var, etype)) { \
	189	var = (typeof(var))(entry); \
	190	WARN_ON(id && (entry)->type != id); \
	191	break; \
	192	}
	193
	194	/* Will cause compile errors if type is not found. */
	195	extern void __ftrace_bad_type(void);
	196
	197	/*
	198	* The trace_assign_type is a verifier that the entry type is
	199	* the same as the type being assigned. To add new types simply
	200	* add a line with the following format:
	201	*
	202	* IF_ASSIGN(var, ent, type, id);
	203	*
	204	* Where "type" is the trace type that includes the trace_entry
	205	* as the "ent" item. And "id" is the trace identifier that is
	206	* used in the trace_type enum.
	207	*
	208	* If the type can have more than one id, then use zero.
	209	*/
	210	#define trace_assign_type(var, ent) \
	211	do { \
	212	IF_ASSIGN(var, ent, struct ftrace_entry, TRACE_FN); \
	213	IF_ASSIGN(var, ent, struct ctx_switch_entry, 0); \
	214	IF_ASSIGN(var, ent, struct trace_field_cont, TRACE_CONT); \
	215	IF_ASSIGN(var, ent, struct stack_entry, TRACE_STACK); \
	216	IF_ASSIGN(var, ent, struct print_entry, TRACE_PRINT); \
	217	IF_ASSIGN(var, ent, struct special_entry, 0); \
	218	IF_ASSIGN(var, ent, struct trace_mmiotrace_rw, \
	219	TRACE_MMIO_RW); \
	220	IF_ASSIGN(var, ent, struct trace_mmiotrace_map, \
	221	TRACE_MMIO_MAP); \
	222	IF_ASSIGN(var, ent, struct trace_boot, TRACE_BOOT); \
	223	__ftrace_bad_type(); \
	224	} while (0)
2c4f035f FW	225
	226	/* Return values for print_line callback */
	227	enum print_line_t {
	228	TRACE_TYPE_PARTIAL_LINE = 0, /* Retry after flushing the seq */
	229	TRACE_TYPE_HANDLED = 1,
	230	TRACE_TYPE_UNHANDLED = 2 /* Relay to other output functions */
	231	};
	232
bc0c38d1 SR	233	/*
	234	* A specific tracer, represented by methods that operate on a trace array:
	235	*/
	236	struct tracer {
	237	const char *name;
	238	void (init)(struct trace_array tr);
	239	void (reset)(struct trace_array tr);
	240	void (open)(struct trace_iterator iter);
107bad8b	241	void (pipe_open)(struct trace_iterator iter);
bc0c38d1 SR	242	void (close)(struct trace_iterator iter);
	243	void (start)(struct trace_iterator iter);
	244	void (stop)(struct trace_iterator iter);
107bad8b SR	245	ssize_t (read)(struct trace_iterator iter,
	246	struct file filp, char __user ubuf,
	247	size_t cnt, loff_t *ppos);
bc0c38d1	248	void (ctrl_update)(struct trace_array tr);
60a11774 SR	249	#ifdef CONFIG_FTRACE_STARTUP_TEST
	250	int (selftest)(struct tracer trace,
	251	struct trace_array *tr);
	252	#endif
2c4f035f	253	enum print_line_t (print_line)(struct trace_iterator iter);
bc0c38d1 SR	254	struct tracer *next;
	255	int print_max;
	256	};
	257
214023c3 SR	258	struct trace_seq {
	259	unsigned char buffer[PAGE_SIZE];
	260	unsigned int len;
6c6c2796	261	unsigned int readpos;
214023c3 SR	262	};
214023c3 SR	263
bc0c38d1 SR	264	/*
	265	* Trace iterator - used by printout routines who present trace
	266	* results to users and which routines might sleep, etc:
	267	*/
	268	struct trace_iterator {
	269	struct trace_array *tr;
	270	struct tracer *trace;
107bad8b	271	void *private;
3928a8a2	272	struct ring_buffer_iter *buffer_iter[NR_CPUS];
4e3c3333	273
53d0aa77 SR	274	/* The below is zeroed out in pipe_read */
53d0aa77 SR	275	struct trace_seq seq;
bc0c38d1	276	struct trace_entry *ent;
4e3c3333	277	int cpu;
3928a8a2	278	u64 ts;
4e3c3333	279
bc0c38d1 SR	280	unsigned long iter_flags;
bc0c38d1 SR	281	loff_t pos;
4c11d7ae	282	long idx;
bc0c38d1 SR	283	};
bc0c38d1 SR	284
45dcd8b8	285	void trace_wake_up(void);
3928a8a2	286	void tracing_reset(struct trace_array *tr, int cpu);
bc0c38d1 SR	287	int tracing_open_generic(struct inode inode, struct file filp);
bc0c38d1 SR	288	struct dentry *tracing_init_dentry(void);
d618b3e6 IM	289	void init_tracer_sysprof_debugfs(struct dentry *d_tracer);
d618b3e6 IM	290
45dcd8b8 PP	291	struct trace_entry tracing_get_trace_entry(struct trace_array tr,
	292	struct trace_array_cpu *data);
	293	void tracing_generic_entry_update(struct trace_entry *entry,
38697053 SR	294	unsigned long flags,
38697053 SR	295	int pc);
45dcd8b8	296
bc0c38d1 SR	297	void ftrace(struct trace_array *tr,
	298	struct trace_array_cpu *data,
	299	unsigned long ip,
	300	unsigned long parent_ip,
38697053	301	unsigned long flags, int pc);
bc0c38d1 SR	302	void tracing_sched_switch_trace(struct trace_array *tr,
	303	struct trace_array_cpu *data,
	304	struct task_struct *prev,
	305	struct task_struct *next,
38697053	306	unsigned long flags, int pc);
bc0c38d1	307	void tracing_record_cmdline(struct task_struct *tsk);
57422797 IM	308
	309	void tracing_sched_wakeup_trace(struct trace_array *tr,
	310	struct trace_array_cpu *data,
	311	struct task_struct *wakee,
	312	struct task_struct *cur,
38697053	313	unsigned long flags, int pc);
f0a920d5 IM	314	void trace_special(struct trace_array *tr,
	315	struct trace_array_cpu *data,
	316	unsigned long arg1,
	317	unsigned long arg2,
38697053	318	unsigned long arg3, int pc);
6fb44b71 SR	319	void trace_function(struct trace_array *tr,
	320	struct trace_array_cpu *data,
	321	unsigned long ip,
	322	unsigned long parent_ip,
38697053	323	unsigned long flags, int pc);
bc0c38d1	324
41bc8144 SR	325	void tracing_start_cmdline_record(void);
41bc8144 SR	326	void tracing_stop_cmdline_record(void);
bc0c38d1 SR	327	int register_tracer(struct tracer *type);
	328	void unregister_tracer(struct tracer *type);
	329
	330	extern unsigned long nsecs_to_usecs(unsigned long nsecs);
	331
	332	extern unsigned long tracing_max_latency;
	333	extern unsigned long tracing_thresh;
	334
	335	void update_max_tr(struct trace_array tr, struct task_struct tsk, int cpu);
	336	void update_max_tr_single(struct trace_array *tr,
	337	struct task_struct *tsk, int cpu);
	338
e309b41d	339	extern cycle_t ftrace_now(int cpu);
bc0c38d1	340
606576ce	341	#ifdef CONFIG_FUNCTION_TRACER
001b6767 SR	342	void tracing_start_function_trace(void);
	343	void tracing_stop_function_trace(void);
	344	#else
	345	# define tracing_start_function_trace() do { } while (0)
	346	# define tracing_stop_function_trace() do { } while (0)
	347	#endif
	348
bc0c38d1 SR	349	#ifdef CONFIG_CONTEXT_SWITCH_TRACER
	350	typedef void
	351	(tracer_switch_func_t)(void private,
5b82a1b0	352	void *__rq,
bc0c38d1 SR	353	struct task_struct *prev,
	354	struct task_struct *next);
	355
	356	struct tracer_switch_ops {
	357	tracer_switch_func_t func;
	358	void *private;
	359	struct tracer_switch_ops *next;
	360	};
	361
bc0c38d1 SR	362	#endif /* CONFIG_CONTEXT_SWITCH_TRACER */
	363
	364	#ifdef CONFIG_DYNAMIC_FTRACE
	365	extern unsigned long ftrace_update_tot_cnt;
d05cdb25 SR	366	#define DYN_FTRACE_TEST_NAME trace_selftest_dynamic_test_func
d05cdb25 SR	367	extern int DYN_FTRACE_TEST_NAME(void);
bc0c38d1 SR	368	#endif
bc0c38d1 SR	369
60a11774	370	#ifdef CONFIG_FTRACE_STARTUP_TEST
60a11774 SR	371	extern int trace_selftest_startup_function(struct tracer *trace,
60a11774 SR	372	struct trace_array *tr);
60a11774 SR	373	extern int trace_selftest_startup_irqsoff(struct tracer *trace,
60a11774 SR	374	struct trace_array *tr);
60a11774 SR	375	extern int trace_selftest_startup_preemptoff(struct tracer *trace,
60a11774 SR	376	struct trace_array *tr);
60a11774 SR	377	extern int trace_selftest_startup_preemptirqsoff(struct tracer *trace,
60a11774 SR	378	struct trace_array *tr);
60a11774 SR	379	extern int trace_selftest_startup_wakeup(struct tracer *trace,
60a11774 SR	380	struct trace_array *tr);
fb1b6d8b SN	381	extern int trace_selftest_startup_nop(struct tracer *trace,
fb1b6d8b SN	382	struct trace_array *tr);
60a11774 SR	383	extern int trace_selftest_startup_sched_switch(struct tracer *trace,
60a11774 SR	384	struct trace_array *tr);
a6dd24f8 IM	385	extern int trace_selftest_startup_sysprof(struct tracer *trace,
a6dd24f8 IM	386	struct trace_array *tr);
60a11774 SR	387	#endif /* CONFIG_FTRACE_STARTUP_TEST */
60a11774 SR	388
c7aafc54	389	extern void head_page(struct trace_array_cpu data);
72829bc3	390	extern int trace_seq_printf(struct trace_seq s, const char fmt, ...);
fc5e27ae PP	391	extern void trace_seq_print_cont(struct trace_seq *s,
fc5e27ae PP	392	struct trace_iterator *iter);
6c6c2796 PP	393	extern ssize_t trace_seq_to_user(struct trace_seq s, char __user ubuf,
6c6c2796 PP	394	size_t cnt);
72829bc3	395	extern long ns2usecs(cycle_t nsec);
801fe400	396	extern int trace_vprintk(unsigned long ip, const char *fmt, va_list args);
c7aafc54	397
4e655519 IM	398	extern unsigned long trace_flags;
4e655519 IM	399
4fcdae83 SR	400	/*
	401	* trace_iterator_flags is an enumeration that defines bit
	402	* positions into trace_flags that controls the output.
	403	*
	404	* NOTE: These bits must match the trace_options array in
	405	* trace.c.
	406	*/
4e655519 IM	407	enum trace_iterator_flags {
	408	TRACE_ITER_PRINT_PARENT = 0x01,
	409	TRACE_ITER_SYM_OFFSET = 0x02,
	410	TRACE_ITER_SYM_ADDR = 0x04,
	411	TRACE_ITER_VERBOSE = 0x08,
	412	TRACE_ITER_RAW = 0x10,
	413	TRACE_ITER_HEX = 0x20,
	414	TRACE_ITER_BIN = 0x40,
	415	TRACE_ITER_BLOCK = 0x80,
	416	TRACE_ITER_STACKTRACE = 0x100,
4ac3ba41	417	TRACE_ITER_SCHED_TREE = 0x200,
f09ce573	418	TRACE_ITER_PRINTK = 0x400,
b2a866f9	419	TRACE_ITER_PREEMPTONLY = 0x800,
4e655519 IM	420	};
4e655519 IM	421
43a15386 FW	422	extern struct tracer nop_trace;
43a15386 FW	423
8f0a056f SR	424	/**
	425	* ftrace_preempt_disable - disable preemption scheduler safe
	426	*
	427	* When tracing can happen inside the scheduler, there exists
	428	* cases that the tracing might happen before the need_resched
	429	* flag is checked. If this happens and the tracer calls
	430	* preempt_enable (after a disable), a schedule might take place
	431	* causing an infinite recursion.
	432	*
	433	* To prevent this, we read the need_recshed flag before
	434	* disabling preemption. When we want to enable preemption we
	435	* check the flag, if it is set, then we call preempt_enable_no_resched.
	436	* Otherwise, we call preempt_enable.
	437	*
	438	* The rational for doing the above is that if need resched is set
	439	* and we have yet to reschedule, we are either in an atomic location
	440	* (where we do not need to check for scheduling) or we are inside
	441	* the scheduler and do not want to resched.
	442	*/
	443	static inline int ftrace_preempt_disable(void)
	444	{
	445	int resched;
	446
	447	resched = need_resched();
	448	preempt_disable_notrace();
	449
	450	return resched;
	451	}
	452
	453	/**
	454	* ftrace_preempt_enable - enable preemption scheduler safe
	455	* @resched: the return value from ftrace_preempt_disable
	456	*
	457	* This is a scheduler safe way to enable preemption and not miss
	458	* any preemption checks. The disabled saved the state of preemption.
	459	* If resched is set, then we were either inside an atomic or
	460	* are inside the scheduler (we would have already scheduled
	461	* otherwise). In this case, we do not want to call normal
	462	* preempt_enable, but preempt_enable_no_resched instead.
	463	*/
	464	static inline void ftrace_preempt_enable(int resched)
	465	{
	466	if (resched)
	467	preempt_enable_no_resched_notrace();
	468	else
	469	preempt_enable_notrace();
	470	}
	471
bc0c38d1	472	#endif /* _LINUX_KERNEL_TRACE_H */