[mirror_ubuntu-zesty-kernel.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>
#include <trace/boot.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_FN_RET,

	__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;
};

/* Function return entry */
struct ftrace_ret_entry {
	struct trace_entry	ent;
	unsigned long		ip;
	unsigned long		parent_ip;
	unsigned long long	calltime;
	unsigned long long	rettime;
};
extern struct tracer 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;
	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);	\
		IF_ASSIGN(var, ent, struct ftrace_ret_entry, TRACE_FN_RET); \
		__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			(*start)(struct trace_array *tr);
	void			(*stop)(struct trace_array *tr);
	void			(*open)(struct trace_iterator *iter);
	void			(*pipe_open)(struct trace_iterator *iter);
	void			(*close)(struct trace_iterator *iter);
	ssize_t			(*read)(struct trace_iterator *iter,
					struct file *filp, char __user *ubuf,
					size_t cnt, loff_t *ppos);
#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;

	cpumask_t		started;
};

int tracing_is_enabled(void);
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
trace_function_return(struct ftrace_retfunc *trace);

void tracing_start_cmdline_record(void);
void tracing_stop_cmdline_record(void);
void tracing_sched_switch_assign_trace(struct trace_array *tr);
void tracing_stop_sched_switch_record(void);
void tracing_start_sched_switch_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 int
seq_print_ip_sym(struct trace_seq *s, unsigned long ip,
		unsigned long sym_flags);
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;

/* Standard output formatting function used for function return traces */
#ifdef CONFIG_FUNCTION_RET_TRACER
extern enum print_line_t print_return_function(struct trace_iterator *iter);
#else
static inline enum print_line_t
print_return_function(struct trace_iterator *iter)
{
	return TRACE_TYPE_UNHANDLED;
}
#endif

/*
 * 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,
};

/*
 * TRACE_ITER_SYM_MASK masks the options in trace_flags that
 * control the output of kernel symbols.
 */
#define TRACE_ITER_SYM_MASK \
	(TRACE_ITER_PRINT_PARENT|TRACE_ITER_SYM_OFFSET|TRACE_ITER_SYM_ADDR)

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>
3f5ec136	11	#include <trace/boot.h>
bc0c38d1	12
72829bc3 TG	13	enum trace_type {
	14	__TRACE_FIRST_TYPE = 0,
	15
	16	TRACE_FN,
	17	TRACE_CTX,
	18	TRACE_WAKE,
dd0e545f	19	TRACE_CONT,
72829bc3	20	TRACE_STACK,
dd0e545f	21	TRACE_PRINT,
72829bc3	22	TRACE_SPECIAL,
bd8ac686 PP	23	TRACE_MMIO_RW,
bd8ac686 PP	24	TRACE_MMIO_MAP,
d13744cd	25	TRACE_BOOT,
15e6cb36	26	TRACE_FN_RET,
72829bc3 TG	27
	28	__TRACE_LAST_TYPE
	29	};
	30
777e208d SR	31	/*
	32	* The trace entry - the most basic unit of tracing. This is what
	33	* is printed in the end as a single line in the trace output, such as:
	34	*
	35	* bash-15816 [01] 235.197585: idle_cpu <- irq_enter
	36	*/
	37	struct trace_entry {
	38	unsigned char type;
	39	unsigned char cpu;
	40	unsigned char flags;
	41	unsigned char preempt_count;
	42	int pid;
	43	};
	44
bc0c38d1 SR	45	/*
	46	* Function trace entry - function address and parent function addres:
	47	*/
	48	struct ftrace_entry {
777e208d	49	struct trace_entry ent;
bc0c38d1 SR	50	unsigned long ip;
	51	unsigned long parent_ip;
	52	};
15e6cb36 FW	53
	54	/* Function return entry */
	55	struct ftrace_ret_entry {
	56	struct trace_entry ent;
	57	unsigned long ip;
	58	unsigned long parent_ip;
	59	unsigned long long calltime;
	60	unsigned long long rettime;
	61	};
d13744cd	62	extern struct tracer boot_tracer;
bc0c38d1 SR	63
	64	/*
	65	* Context switch trace entry - which task (and prio) we switched from/to:
	66	*/
	67	struct ctx_switch_entry {
777e208d	68	struct trace_entry ent;
bc0c38d1 SR	69	unsigned int prev_pid;
	70	unsigned char prev_prio;
	71	unsigned char prev_state;
	72	unsigned int next_pid;
	73	unsigned char next_prio;
bac524d3	74	unsigned char next_state;
80b5e940	75	unsigned int next_cpu;
bc0c38d1 SR	76	};
bc0c38d1 SR	77
f0a920d5 IM	78	/*
	79	* Special (free-form) trace entry:
	80	*/
	81	struct special_entry {
777e208d	82	struct trace_entry ent;
f0a920d5 IM	83	unsigned long arg1;
	84	unsigned long arg2;
	85	unsigned long arg3;
	86	};
	87
86387f7e IM	88	/*
	89	* Stack-trace entry:
	90	*/
	91
74f4e369	92	#define FTRACE_STACK_ENTRIES 8
86387f7e IM	93
86387f7e IM	94	struct stack_entry {
777e208d	95	struct trace_entry ent;
86387f7e IM	96	unsigned long caller[FTRACE_STACK_ENTRIES];
	97	};
	98
dd0e545f SR	99	/*
	100	* ftrace_printk entry:
	101	*/
	102	struct print_entry {
777e208d	103	struct trace_entry ent;
dd0e545f SR	104	unsigned long ip;
	105	char buf[];
	106	};
	107
777e208d SR	108	#define TRACE_OLD_SIZE 88
	109
	110	struct trace_field_cont {
	111	unsigned char type;
	112	/* Temporary till we get rid of this completely */
	113	char buf[TRACE_OLD_SIZE - 1];
	114	};
	115
	116	struct trace_mmiotrace_rw {
	117	struct trace_entry ent;
	118	struct mmiotrace_rw rw;
	119	};
	120
	121	struct trace_mmiotrace_map {
	122	struct trace_entry ent;
	123	struct mmiotrace_map map;
	124	};
	125
	126	struct trace_boot {
	127	struct trace_entry ent;
	128	struct boot_trace initcall;
	129	};
	130
fc5e27ae PP	131	/*
	132	* trace_flag_type is an enumeration that holds different
	133	* states when a trace occurs. These are:
9244489a SR	134	* IRQS_OFF - interrupts were disabled
	135	* IRQS_NOSUPPORT - arch does not support irqs_disabled_flags
	136	* NEED_RESCED - reschedule is requested
	137	* HARDIRQ - inside an interrupt handler
	138	* SOFTIRQ - inside a softirq handler
	139	* CONT - multiple entries hold the trace item
fc5e27ae PP	140	*/
	141	enum trace_flag_type {
	142	TRACE_FLAG_IRQS_OFF = 0x01,
9244489a SR	143	TRACE_FLAG_IRQS_NOSUPPORT = 0x02,
	144	TRACE_FLAG_NEED_RESCHED = 0x04,
	145	TRACE_FLAG_HARDIRQ = 0x08,
	146	TRACE_FLAG_SOFTIRQ = 0x10,
	147	TRACE_FLAG_CONT = 0x20,
fc5e27ae PP	148	};
fc5e27ae PP	149
5bf9a1ee	150	#define TRACE_BUF_SIZE 1024
bc0c38d1 SR	151
	152	/*
	153	* The CPU trace array - it consists of thousands of trace entries
	154	* plus some other descriptor data: (for example which task started
	155	* the trace, etc.)
	156	*/
	157	struct trace_array_cpu {
bc0c38d1	158	atomic_t disabled;
4e3c3333	159
c7aafc54	160	/* these fields get copied into max-trace: */
c7aafc54	161	unsigned long trace_idx;
53d0aa77	162	unsigned long overrun;
bc0c38d1 SR	163	unsigned long saved_latency;
	164	unsigned long critical_start;
	165	unsigned long critical_end;
	166	unsigned long critical_sequence;
	167	unsigned long nice;
	168	unsigned long policy;
	169	unsigned long rt_priority;
	170	cycle_t preempt_timestamp;
	171	pid_t pid;
	172	uid_t uid;
	173	char comm[TASK_COMM_LEN];
	174	};
	175
	176	struct trace_iterator;
	177
	178	/*
	179	* The trace array - an array of per-CPU trace arrays. This is the
	180	* highest level data structure that individual tracers deal with.
	181	* They have on/off state as well:
	182	*/
	183	struct trace_array {
3928a8a2	184	struct ring_buffer *buffer;
bc0c38d1	185	unsigned long entries;
bc0c38d1 SR	186	int cpu;
bc0c38d1 SR	187	cycle_t time_start;
b3806b43	188	struct task_struct *waiter;
bc0c38d1 SR	189	struct trace_array_cpu *data[NR_CPUS];
	190	};
	191
7104f300 SR	192	#define FTRACE_CMP_TYPE(var, type) \
	193	__builtin_types_compatible_p(typeof(var), type *)
	194
	195	#undef IF_ASSIGN
	196	#define IF_ASSIGN(var, entry, etype, id) \
	197	if (FTRACE_CMP_TYPE(var, etype)) { \
	198	var = (typeof(var))(entry); \
	199	WARN_ON(id && (entry)->type != id); \
	200	break; \
	201	}
	202
	203	/* Will cause compile errors if type is not found. */
	204	extern void __ftrace_bad_type(void);
	205
	206	/*
	207	* The trace_assign_type is a verifier that the entry type is
	208	* the same as the type being assigned. To add new types simply
	209	* add a line with the following format:
	210	*
	211	* IF_ASSIGN(var, ent, type, id);
	212	*
	213	* Where "type" is the trace type that includes the trace_entry
	214	* as the "ent" item. And "id" is the trace identifier that is
	215	* used in the trace_type enum.
	216	*
	217	* If the type can have more than one id, then use zero.
	218	*/
	219	#define trace_assign_type(var, ent) \
	220	do { \
	221	IF_ASSIGN(var, ent, struct ftrace_entry, TRACE_FN); \
	222	IF_ASSIGN(var, ent, struct ctx_switch_entry, 0); \
	223	IF_ASSIGN(var, ent, struct trace_field_cont, TRACE_CONT); \
	224	IF_ASSIGN(var, ent, struct stack_entry, TRACE_STACK); \
	225	IF_ASSIGN(var, ent, struct print_entry, TRACE_PRINT); \
	226	IF_ASSIGN(var, ent, struct special_entry, 0); \
	227	IF_ASSIGN(var, ent, struct trace_mmiotrace_rw, \
	228	TRACE_MMIO_RW); \
	229	IF_ASSIGN(var, ent, struct trace_mmiotrace_map, \
	230	TRACE_MMIO_MAP); \
	231	IF_ASSIGN(var, ent, struct trace_boot, TRACE_BOOT); \
15e6cb36	232	IF_ASSIGN(var, ent, struct ftrace_ret_entry, TRACE_FN_RET); \
7104f300 SR	233	__ftrace_bad_type(); \
7104f300 SR	234	} while (0)
2c4f035f FW	235
	236	/* Return values for print_line callback */
	237	enum print_line_t {
	238	TRACE_TYPE_PARTIAL_LINE = 0, /* Retry after flushing the seq */
	239	TRACE_TYPE_HANDLED = 1,
	240	TRACE_TYPE_UNHANDLED = 2 /* Relay to other output functions */
	241	};
	242
bc0c38d1 SR	243	/*
	244	* A specific tracer, represented by methods that operate on a trace array:
	245	*/
	246	struct tracer {
	247	const char *name;
	248	void (init)(struct trace_array tr);
	249	void (reset)(struct trace_array tr);
9036990d SR	250	void (start)(struct trace_array tr);
9036990d SR	251	void (stop)(struct trace_array tr);
bc0c38d1	252	void (open)(struct trace_iterator iter);
107bad8b	253	void (pipe_open)(struct trace_iterator iter);
bc0c38d1	254	void (close)(struct trace_iterator iter);
107bad8b SR	255	ssize_t (read)(struct trace_iterator iter,
	256	struct file filp, char __user ubuf,
	257	size_t cnt, loff_t *ppos);
60a11774 SR	258	#ifdef CONFIG_FTRACE_STARTUP_TEST
	259	int (selftest)(struct tracer trace,
	260	struct trace_array *tr);
	261	#endif
2c4f035f	262	enum print_line_t (print_line)(struct trace_iterator iter);
bc0c38d1 SR	263	struct tracer *next;
	264	int print_max;
	265	};
	266
214023c3 SR	267	struct trace_seq {
	268	unsigned char buffer[PAGE_SIZE];
	269	unsigned int len;
6c6c2796	270	unsigned int readpos;
214023c3 SR	271	};
214023c3 SR	272
bc0c38d1 SR	273	/*
	274	* Trace iterator - used by printout routines who present trace
	275	* results to users and which routines might sleep, etc:
	276	*/
	277	struct trace_iterator {
	278	struct trace_array *tr;
	279	struct tracer *trace;
107bad8b	280	void *private;
3928a8a2	281	struct ring_buffer_iter *buffer_iter[NR_CPUS];
4e3c3333	282
53d0aa77 SR	283	/* The below is zeroed out in pipe_read */
53d0aa77 SR	284	struct trace_seq seq;
bc0c38d1	285	struct trace_entry *ent;
4e3c3333	286	int cpu;
3928a8a2	287	u64 ts;
4e3c3333	288
bc0c38d1 SR	289	unsigned long iter_flags;
bc0c38d1 SR	290	loff_t pos;
4c11d7ae	291	long idx;
a309720c SR	292
a309720c SR	293	cpumask_t started;
bc0c38d1 SR	294	};
bc0c38d1 SR	295
9036990d	296	int tracing_is_enabled(void);
45dcd8b8	297	void trace_wake_up(void);
3928a8a2	298	void tracing_reset(struct trace_array *tr, int cpu);
bc0c38d1 SR	299	int tracing_open_generic(struct inode inode, struct file filp);
bc0c38d1 SR	300	struct dentry *tracing_init_dentry(void);
d618b3e6 IM	301	void init_tracer_sysprof_debugfs(struct dentry *d_tracer);
d618b3e6 IM	302
45dcd8b8 PP	303	struct trace_entry tracing_get_trace_entry(struct trace_array tr,
	304	struct trace_array_cpu *data);
	305	void tracing_generic_entry_update(struct trace_entry *entry,
38697053 SR	306	unsigned long flags,
38697053 SR	307	int pc);
45dcd8b8	308
bc0c38d1 SR	309	void ftrace(struct trace_array *tr,
	310	struct trace_array_cpu *data,
	311	unsigned long ip,
	312	unsigned long parent_ip,
38697053	313	unsigned long flags, int pc);
bc0c38d1 SR	314	void tracing_sched_switch_trace(struct trace_array *tr,
	315	struct trace_array_cpu *data,
	316	struct task_struct *prev,
	317	struct task_struct *next,
38697053	318	unsigned long flags, int pc);
bc0c38d1	319	void tracing_record_cmdline(struct task_struct *tsk);
57422797 IM	320
	321	void tracing_sched_wakeup_trace(struct trace_array *tr,
	322	struct trace_array_cpu *data,
	323	struct task_struct *wakee,
	324	struct task_struct *cur,
38697053	325	unsigned long flags, int pc);
f0a920d5 IM	326	void trace_special(struct trace_array *tr,
	327	struct trace_array_cpu *data,
	328	unsigned long arg1,
	329	unsigned long arg2,
38697053	330	unsigned long arg3, int pc);
6fb44b71 SR	331	void trace_function(struct trace_array *tr,
	332	struct trace_array_cpu *data,
	333	unsigned long ip,
	334	unsigned long parent_ip,
38697053	335	unsigned long flags, int pc);
15e6cb36 FW	336	void
15e6cb36 FW	337	trace_function_return(struct ftrace_retfunc *trace);
bc0c38d1	338
41bc8144 SR	339	void tracing_start_cmdline_record(void);
41bc8144 SR	340	void tracing_stop_cmdline_record(void);
e168e051 SR	341	void tracing_sched_switch_assign_trace(struct trace_array *tr);
	342	void tracing_stop_sched_switch_record(void);
	343	void tracing_start_sched_switch_record(void);
bc0c38d1 SR	344	int register_tracer(struct tracer *type);
	345	void unregister_tracer(struct tracer *type);
	346
	347	extern unsigned long nsecs_to_usecs(unsigned long nsecs);
	348
	349	extern unsigned long tracing_max_latency;
	350	extern unsigned long tracing_thresh;
	351
	352	void update_max_tr(struct trace_array tr, struct task_struct tsk, int cpu);
	353	void update_max_tr_single(struct trace_array *tr,
	354	struct task_struct *tsk, int cpu);
	355
e309b41d	356	extern cycle_t ftrace_now(int cpu);
bc0c38d1	357
606576ce	358	#ifdef CONFIG_FUNCTION_TRACER
001b6767 SR	359	void tracing_start_function_trace(void);
	360	void tracing_stop_function_trace(void);
	361	#else
	362	# define tracing_start_function_trace() do { } while (0)
	363	# define tracing_stop_function_trace() do { } while (0)
	364	#endif
	365
bc0c38d1 SR	366	#ifdef CONFIG_CONTEXT_SWITCH_TRACER
	367	typedef void
	368	(tracer_switch_func_t)(void private,
5b82a1b0	369	void *__rq,
bc0c38d1 SR	370	struct task_struct *prev,
	371	struct task_struct *next);
	372
	373	struct tracer_switch_ops {
	374	tracer_switch_func_t func;
	375	void *private;
	376	struct tracer_switch_ops *next;
	377	};
	378
bc0c38d1 SR	379	#endif /* CONFIG_CONTEXT_SWITCH_TRACER */
	380
	381	#ifdef CONFIG_DYNAMIC_FTRACE
	382	extern unsigned long ftrace_update_tot_cnt;
d05cdb25 SR	383	#define DYN_FTRACE_TEST_NAME trace_selftest_dynamic_test_func
d05cdb25 SR	384	extern int DYN_FTRACE_TEST_NAME(void);
bc0c38d1 SR	385	#endif
bc0c38d1 SR	386
60a11774	387	#ifdef CONFIG_FTRACE_STARTUP_TEST
60a11774 SR	388	extern int trace_selftest_startup_function(struct tracer *trace,
60a11774 SR	389	struct trace_array *tr);
60a11774 SR	390	extern int trace_selftest_startup_irqsoff(struct tracer *trace,
60a11774 SR	391	struct trace_array *tr);
60a11774 SR	392	extern int trace_selftest_startup_preemptoff(struct tracer *trace,
60a11774 SR	393	struct trace_array *tr);
60a11774 SR	394	extern int trace_selftest_startup_preemptirqsoff(struct tracer *trace,
60a11774 SR	395	struct trace_array *tr);
60a11774 SR	396	extern int trace_selftest_startup_wakeup(struct tracer *trace,
60a11774 SR	397	struct trace_array *tr);
fb1b6d8b SN	398	extern int trace_selftest_startup_nop(struct tracer *trace,
fb1b6d8b SN	399	struct trace_array *tr);
60a11774 SR	400	extern int trace_selftest_startup_sched_switch(struct tracer *trace,
60a11774 SR	401	struct trace_array *tr);
a6dd24f8 IM	402	extern int trace_selftest_startup_sysprof(struct tracer *trace,
a6dd24f8 IM	403	struct trace_array *tr);
60a11774 SR	404	#endif /* CONFIG_FTRACE_STARTUP_TEST */
60a11774 SR	405
c7aafc54	406	extern void head_page(struct trace_array_cpu data);
72829bc3	407	extern int trace_seq_printf(struct trace_seq s, const char fmt, ...);
fc5e27ae PP	408	extern void trace_seq_print_cont(struct trace_seq *s,
fc5e27ae PP	409	struct trace_iterator *iter);
15e6cb36 FW	410
	411	extern int
	412	seq_print_ip_sym(struct trace_seq *s, unsigned long ip,
	413	unsigned long sym_flags);
6c6c2796 PP	414	extern ssize_t trace_seq_to_user(struct trace_seq s, char __user ubuf,
6c6c2796 PP	415	size_t cnt);
72829bc3	416	extern long ns2usecs(cycle_t nsec);
801fe400	417	extern int trace_vprintk(unsigned long ip, const char *fmt, va_list args);
c7aafc54	418
4e655519 IM	419	extern unsigned long trace_flags;
4e655519 IM	420
15e6cb36 FW	421	/* Standard output formatting function used for function return traces */
	422	#ifdef CONFIG_FUNCTION_RET_TRACER
	423	extern enum print_line_t print_return_function(struct trace_iterator *iter);
	424	#else
	425	static inline enum print_line_t
	426	print_return_function(struct trace_iterator *iter)
	427	{
	428	return TRACE_TYPE_UNHANDLED;
	429	}
	430	#endif
	431
4fcdae83 SR	432	/*
	433	* trace_iterator_flags is an enumeration that defines bit
	434	* positions into trace_flags that controls the output.
	435	*
	436	* NOTE: These bits must match the trace_options array in
	437	* trace.c.
	438	*/
4e655519 IM	439	enum trace_iterator_flags {
	440	TRACE_ITER_PRINT_PARENT = 0x01,
	441	TRACE_ITER_SYM_OFFSET = 0x02,
	442	TRACE_ITER_SYM_ADDR = 0x04,
	443	TRACE_ITER_VERBOSE = 0x08,
	444	TRACE_ITER_RAW = 0x10,
	445	TRACE_ITER_HEX = 0x20,
	446	TRACE_ITER_BIN = 0x40,
	447	TRACE_ITER_BLOCK = 0x80,
	448	TRACE_ITER_STACKTRACE = 0x100,
4ac3ba41	449	TRACE_ITER_SCHED_TREE = 0x200,
f09ce573	450	TRACE_ITER_PRINTK = 0x400,
b2a866f9	451	TRACE_ITER_PREEMPTONLY = 0x800,
4e655519 IM	452	};
4e655519 IM	453
15e6cb36 FW	454	/*
	455	* TRACE_ITER_SYM_MASK masks the options in trace_flags that
	456	* control the output of kernel symbols.
	457	*/
	458	#define TRACE_ITER_SYM_MASK \
	459	(TRACE_ITER_PRINT_PARENT\|TRACE_ITER_SYM_OFFSET\|TRACE_ITER_SYM_ADDR)
	460
43a15386 FW	461	extern struct tracer nop_trace;
43a15386 FW	462
8f0a056f SR	463	/**
	464	* ftrace_preempt_disable - disable preemption scheduler safe
	465	*
	466	* When tracing can happen inside the scheduler, there exists
	467	* cases that the tracing might happen before the need_resched
	468	* flag is checked. If this happens and the tracer calls
	469	* preempt_enable (after a disable), a schedule might take place
	470	* causing an infinite recursion.
	471	*
	472	* To prevent this, we read the need_recshed flag before
	473	* disabling preemption. When we want to enable preemption we
	474	* check the flag, if it is set, then we call preempt_enable_no_resched.
	475	* Otherwise, we call preempt_enable.
	476	*
	477	* The rational for doing the above is that if need resched is set
	478	* and we have yet to reschedule, we are either in an atomic location
	479	* (where we do not need to check for scheduling) or we are inside
	480	* the scheduler and do not want to resched.
	481	*/
	482	static inline int ftrace_preempt_disable(void)
	483	{
	484	int resched;
	485
	486	resched = need_resched();
	487	preempt_disable_notrace();
	488
	489	return resched;
	490	}
	491
	492	/**
	493	* ftrace_preempt_enable - enable preemption scheduler safe
	494	* @resched: the return value from ftrace_preempt_disable
	495	*
	496	* This is a scheduler safe way to enable preemption and not miss
	497	* any preemption checks. The disabled saved the state of preemption.
	498	* If resched is set, then we were either inside an atomic or
	499	* are inside the scheduler (we would have already scheduled
	500	* otherwise). In this case, we do not want to call normal
	501	* preempt_enable, but preempt_enable_no_resched instead.
	502	*/
	503	static inline void ftrace_preempt_enable(int resched)
	504	{
	505	if (resched)
	506	preempt_enable_no_resched_notrace();
	507	else
	508	preempt_enable_notrace();
	509	}
	510
bc0c38d1	511	#endif /* _LINUX_KERNEL_TRACE_H */