ftrace.h 14.7 KB
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/*
 * Ftrace header.  For implementation details beyond the random comments
 * scattered below, see: Documentation/trace/ftrace-design.txt
 */

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#ifndef _LINUX_FTRACE_H
#define _LINUX_FTRACE_H

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#include <linux/trace_clock.h>
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#include <linux/kallsyms.h>
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#include <linux/linkage.h>
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#include <linux/bitops.h>
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#include <linux/module.h>
#include <linux/ktime.h>
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#include <linux/sched.h>
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#include <linux/types.h>
#include <linux/init.h>
#include <linux/fs.h>
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#include <asm/ftrace.h>

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#ifdef CONFIG_FUNCTION_TRACER
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extern int ftrace_enabled;
extern int
ftrace_enable_sysctl(struct ctl_table *table, int write,
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		     void __user *buffer, size_t *lenp,
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		     loff_t *ppos);

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typedef void (*ftrace_func_t)(unsigned long ip, unsigned long parent_ip);

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struct ftrace_hash;

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struct ftrace_ops {
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	ftrace_func_t			func;
	struct ftrace_ops		*next;
#ifdef CONFIG_DYNAMIC_FTRACE
	struct ftrace_hash		*notrace_hash;
	struct ftrace_hash		*filter_hash;
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	unsigned long			flags;
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#endif
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};

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extern int function_trace_stop;

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/*
 * Type of the current tracing.
 */
enum ftrace_tracing_type_t {
	FTRACE_TYPE_ENTER = 0, /* Hook the call of the function */
	FTRACE_TYPE_RETURN,	/* Hook the return of the function */
};

/* Current tracing type, default is FTRACE_TYPE_ENTER */
extern enum ftrace_tracing_type_t ftrace_tracing_type;

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/**
 * ftrace_stop - stop function tracer.
 *
 * A quick way to stop the function tracer. Note this an on off switch,
 * it is not something that is recursive like preempt_disable.
 * This does not disable the calling of mcount, it only stops the
 * calling of functions from mcount.
 */
static inline void ftrace_stop(void)
{
	function_trace_stop = 1;
}

/**
 * ftrace_start - start the function tracer.
 *
 * This function is the inverse of ftrace_stop. This does not enable
 * the function tracing if the function tracer is disabled. This only
 * sets the function tracer flag to continue calling the functions
 * from mcount.
 */
static inline void ftrace_start(void)
{
	function_trace_stop = 0;
}

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/*
 * The ftrace_ops must be a static and should also
 * be read_mostly.  These functions do modify read_mostly variables
 * so use them sparely. Never free an ftrace_op or modify the
 * next pointer after it has been registered. Even after unregistering
 * it, the next pointer may still be used internally.
 */
int register_ftrace_function(struct ftrace_ops *ops);
int unregister_ftrace_function(struct ftrace_ops *ops);
void clear_ftrace_function(void);

extern void ftrace_stub(unsigned long a0, unsigned long a1);

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#else /* !CONFIG_FUNCTION_TRACER */
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/*
 * (un)register_ftrace_function must be a macro since the ops parameter
 * must not be evaluated.
 */
#define register_ftrace_function(ops) ({ 0; })
#define unregister_ftrace_function(ops) ({ 0; })
static inline void clear_ftrace_function(void) { }
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static inline void ftrace_kill(void) { }
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static inline void ftrace_stop(void) { }
static inline void ftrace_start(void) { }
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#endif /* CONFIG_FUNCTION_TRACER */
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#ifdef CONFIG_STACK_TRACER
extern int stack_tracer_enabled;
int
stack_trace_sysctl(struct ctl_table *table, int write,
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		   void __user *buffer, size_t *lenp,
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		   loff_t *ppos);
#endif

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struct ftrace_func_command {
	struct list_head	list;
	char			*name;
	int			(*func)(char *func, char *cmd,
					char *params, int enable);
};

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#ifdef CONFIG_DYNAMIC_FTRACE
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int ftrace_arch_code_modify_prepare(void);
int ftrace_arch_code_modify_post_process(void);

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struct seq_file;

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struct ftrace_probe_ops {
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	void			(*func)(unsigned long ip,
					unsigned long parent_ip,
					void **data);
	int			(*callback)(unsigned long ip, void **data);
	void			(*free)(void **data);
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	int			(*print)(struct seq_file *m,
					 unsigned long ip,
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					 struct ftrace_probe_ops *ops,
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					 void *data);
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};

extern int
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register_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
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			      void *data);
extern void
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unregister_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
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				void *data);
extern void
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unregister_ftrace_function_probe_func(char *glob, struct ftrace_probe_ops *ops);
extern void unregister_ftrace_function_probe_all(char *glob);
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extern int ftrace_text_reserved(void *start, void *end);

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enum {
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	FTRACE_FL_ENABLED	= (1 << 30),
	FTRACE_FL_FREE		= (1 << 31),
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};

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#define FTRACE_FL_MASK		(0x3UL << 30)
#define FTRACE_REF_MAX		((1 << 30) - 1)

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struct dyn_ftrace {
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	union {
		unsigned long		ip; /* address of mcount call-site */
		struct dyn_ftrace	*freelist;
	};
	union {
		unsigned long		flags;
		struct dyn_ftrace	*newlist;
	};
	struct dyn_arch_ftrace		arch;
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};

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int ftrace_force_update(void);
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void ftrace_set_filter(unsigned char *buf, int len, int reset);
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int register_ftrace_command(struct ftrace_func_command *cmd);
int unregister_ftrace_command(struct ftrace_func_command *cmd);

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/* defined in arch */
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extern int ftrace_ip_converted(unsigned long ip);
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extern int ftrace_dyn_arch_init(void *data);
extern int ftrace_update_ftrace_func(ftrace_func_t func);
extern void ftrace_caller(void);
extern void ftrace_call(void);
extern void mcount_call(void);
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#ifndef FTRACE_ADDR
#define FTRACE_ADDR ((unsigned long)ftrace_caller)
#endif
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#ifdef CONFIG_FUNCTION_GRAPH_TRACER
extern void ftrace_graph_caller(void);
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extern int ftrace_enable_ftrace_graph_caller(void);
extern int ftrace_disable_ftrace_graph_caller(void);
#else
static inline int ftrace_enable_ftrace_graph_caller(void) { return 0; }
static inline int ftrace_disable_ftrace_graph_caller(void) { return 0; }
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#endif
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/**
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 * ftrace_make_nop - convert code into nop
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 * @mod: module structure if called by module load initialization
 * @rec: the mcount call site record
 * @addr: the address that the call site should be calling
 *
 * This is a very sensitive operation and great care needs
 * to be taken by the arch.  The operation should carefully
 * read the location, check to see if what is read is indeed
 * what we expect it to be, and then on success of the compare,
 * it should write to the location.
 *
 * The code segment at @rec->ip should be a caller to @addr
 *
 * Return must be:
 *  0 on success
 *  -EFAULT on error reading the location
 *  -EINVAL on a failed compare of the contents
 *  -EPERM  on error writing to the location
 * Any other value will be considered a failure.
 */
extern int ftrace_make_nop(struct module *mod,
			   struct dyn_ftrace *rec, unsigned long addr);
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/**
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 * ftrace_make_call - convert a nop call site into a call to addr
 * @rec: the mcount call site record
 * @addr: the address that the call site should call
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 *
 * This is a very sensitive operation and great care needs
 * to be taken by the arch.  The operation should carefully
 * read the location, check to see if what is read is indeed
 * what we expect it to be, and then on success of the compare,
 * it should write to the location.
 *
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 * The code segment at @rec->ip should be a nop
 *
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 * Return must be:
 *  0 on success
 *  -EFAULT on error reading the location
 *  -EINVAL on a failed compare of the contents
 *  -EPERM  on error writing to the location
 * Any other value will be considered a failure.
 */
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extern int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr);

/* May be defined in arch */
extern int ftrace_arch_read_dyn_info(char *buf, int size);
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extern int skip_trace(unsigned long ip);

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extern void ftrace_disable_daemon(void);
extern void ftrace_enable_daemon(void);
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#else
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static inline int skip_trace(unsigned long ip) { return 0; }
static inline int ftrace_force_update(void) { return 0; }
static inline void ftrace_set_filter(unsigned char *buf, int len, int reset)
{
}
static inline void ftrace_disable_daemon(void) { }
static inline void ftrace_enable_daemon(void) { }
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static inline void ftrace_release_mod(struct module *mod) {}
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static inline int register_ftrace_command(struct ftrace_func_command *cmd)
{
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	return -EINVAL;
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}
static inline int unregister_ftrace_command(char *cmd_name)
{
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	return -EINVAL;
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}
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static inline int ftrace_text_reserved(void *start, void *end)
{
	return 0;
}
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#endif /* CONFIG_DYNAMIC_FTRACE */
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/* totally disable ftrace - can not re-enable after this */
void ftrace_kill(void);

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static inline void tracer_disable(void)
{
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#ifdef CONFIG_FUNCTION_TRACER
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	ftrace_enabled = 0;
#endif
}

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/*
 * Ftrace disable/restore without lock. Some synchronization mechanism
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 * must be used to prevent ftrace_enabled to be changed between
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 * disable/restore.
 */
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static inline int __ftrace_enabled_save(void)
{
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#ifdef CONFIG_FUNCTION_TRACER
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	int saved_ftrace_enabled = ftrace_enabled;
	ftrace_enabled = 0;
	return saved_ftrace_enabled;
#else
	return 0;
#endif
}

static inline void __ftrace_enabled_restore(int enabled)
{
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#ifdef CONFIG_FUNCTION_TRACER
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	ftrace_enabled = enabled;
#endif
}

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#ifndef HAVE_ARCH_CALLER_ADDR
# ifdef CONFIG_FRAME_POINTER
#  define CALLER_ADDR0 ((unsigned long)__builtin_return_address(0))
#  define CALLER_ADDR1 ((unsigned long)__builtin_return_address(1))
#  define CALLER_ADDR2 ((unsigned long)__builtin_return_address(2))
#  define CALLER_ADDR3 ((unsigned long)__builtin_return_address(3))
#  define CALLER_ADDR4 ((unsigned long)__builtin_return_address(4))
#  define CALLER_ADDR5 ((unsigned long)__builtin_return_address(5))
#  define CALLER_ADDR6 ((unsigned long)__builtin_return_address(6))
# else
#  define CALLER_ADDR0 ((unsigned long)__builtin_return_address(0))
#  define CALLER_ADDR1 0UL
#  define CALLER_ADDR2 0UL
#  define CALLER_ADDR3 0UL
#  define CALLER_ADDR4 0UL
#  define CALLER_ADDR5 0UL
#  define CALLER_ADDR6 0UL
# endif
#endif /* ifndef HAVE_ARCH_CALLER_ADDR */
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#ifdef CONFIG_IRQSOFF_TRACER
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  extern void time_hardirqs_on(unsigned long a0, unsigned long a1);
  extern void time_hardirqs_off(unsigned long a0, unsigned long a1);
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#else
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  static inline void time_hardirqs_on(unsigned long a0, unsigned long a1) { }
  static inline void time_hardirqs_off(unsigned long a0, unsigned long a1) { }
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#endif

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#ifdef CONFIG_PREEMPT_TRACER
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  extern void trace_preempt_on(unsigned long a0, unsigned long a1);
  extern void trace_preempt_off(unsigned long a0, unsigned long a1);
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#else
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  static inline void trace_preempt_on(unsigned long a0, unsigned long a1) { }
  static inline void trace_preempt_off(unsigned long a0, unsigned long a1) { }
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#endif

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#ifdef CONFIG_FTRACE_MCOUNT_RECORD
extern void ftrace_init(void);
#else
static inline void ftrace_init(void) { }
#endif

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/*
 * Structure that defines an entry function trace.
 */
struct ftrace_graph_ent {
	unsigned long func; /* Current function */
	int depth;
};
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/*
 * Structure that defines a return function trace.
 */
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struct ftrace_graph_ret {
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	unsigned long func; /* Current function */
	unsigned long long calltime;
	unsigned long long rettime;
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	/* Number of functions that overran the depth limit for current task */
	unsigned long overrun;
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	int depth;
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};

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/* Type of the callback handlers for tracing function graph*/
typedef void (*trace_func_graph_ret_t)(struct ftrace_graph_ret *); /* return */
typedef int (*trace_func_graph_ent_t)(struct ftrace_graph_ent *); /* entry */

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#ifdef CONFIG_FUNCTION_GRAPH_TRACER
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/* for init task */
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#define INIT_FTRACE_GRAPH		.ret_stack = NULL,
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/*
 * Stack of return addresses for functions
 * of a thread.
 * Used in struct thread_info
 */
struct ftrace_ret_stack {
	unsigned long ret;
	unsigned long func;
	unsigned long long calltime;
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	unsigned long long subtime;
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	unsigned long fp;
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};

/*
 * Primary handler of a function return.
 * It relays on ftrace_return_to_handler.
 * Defined in entry_32/64.S
 */
extern void return_to_handler(void);

extern int
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ftrace_push_return_trace(unsigned long ret, unsigned long func, int *depth,
			 unsigned long frame_pointer);
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/*
 * Sometimes we don't want to trace a function with the function
 * graph tracer but we want them to keep traced by the usual function
 * tracer if the function graph tracer is not configured.
 */
#define __notrace_funcgraph		notrace

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/*
 * We want to which function is an entrypoint of a hardirq.
 * That will help us to put a signal on output.
 */
#define __irq_entry		 __attribute__((__section__(".irqentry.text")))

/* Limits of hardirq entrypoints */
extern char __irqentry_text_start[];
extern char __irqentry_text_end[];

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#define FTRACE_RETFUNC_DEPTH 50
#define FTRACE_RETSTACK_ALLOC_SIZE 32
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extern int register_ftrace_graph(trace_func_graph_ret_t retfunc,
				trace_func_graph_ent_t entryfunc);

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extern void ftrace_graph_stop(void);

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/* The current handlers in use */
extern trace_func_graph_ret_t ftrace_graph_return;
extern trace_func_graph_ent_t ftrace_graph_entry;
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extern void unregister_ftrace_graph(void);
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extern void ftrace_graph_init_task(struct task_struct *t);
extern void ftrace_graph_exit_task(struct task_struct *t);
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extern void ftrace_graph_init_idle_task(struct task_struct *t, int cpu);
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static inline int task_curr_ret_stack(struct task_struct *t)
{
	return t->curr_ret_stack;
}
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static inline void pause_graph_tracing(void)
{
	atomic_inc(&current->tracing_graph_pause);
}

static inline void unpause_graph_tracing(void)
{
	atomic_dec(&current->tracing_graph_pause);
}
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#else /* !CONFIG_FUNCTION_GRAPH_TRACER */
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#define __notrace_funcgraph
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#define __irq_entry
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#define INIT_FTRACE_GRAPH
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static inline void ftrace_graph_init_task(struct task_struct *t) { }
static inline void ftrace_graph_exit_task(struct task_struct *t) { }
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static inline void ftrace_graph_init_idle_task(struct task_struct *t, int cpu) { }
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static inline int register_ftrace_graph(trace_func_graph_ret_t retfunc,
			  trace_func_graph_ent_t entryfunc)
{
	return -1;
}
static inline void unregister_ftrace_graph(void) { }

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static inline int task_curr_ret_stack(struct task_struct *tsk)
{
	return -1;
}
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static inline void pause_graph_tracing(void) { }
static inline void unpause_graph_tracing(void) { }
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#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
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#ifdef CONFIG_TRACING

/* flags for current->trace */
enum {
	TSK_TRACE_FL_TRACE_BIT	= 0,
	TSK_TRACE_FL_GRAPH_BIT	= 1,
};
enum {
	TSK_TRACE_FL_TRACE	= 1 << TSK_TRACE_FL_TRACE_BIT,
	TSK_TRACE_FL_GRAPH	= 1 << TSK_TRACE_FL_GRAPH_BIT,
};

static inline void set_tsk_trace_trace(struct task_struct *tsk)
{
	set_bit(TSK_TRACE_FL_TRACE_BIT, &tsk->trace);
}

static inline void clear_tsk_trace_trace(struct task_struct *tsk)
{
	clear_bit(TSK_TRACE_FL_TRACE_BIT, &tsk->trace);
}

static inline int test_tsk_trace_trace(struct task_struct *tsk)
{
	return tsk->trace & TSK_TRACE_FL_TRACE;
}

static inline void set_tsk_trace_graph(struct task_struct *tsk)
{
	set_bit(TSK_TRACE_FL_GRAPH_BIT, &tsk->trace);
}

static inline void clear_tsk_trace_graph(struct task_struct *tsk)
{
	clear_bit(TSK_TRACE_FL_GRAPH_BIT, &tsk->trace);
}

static inline int test_tsk_trace_graph(struct task_struct *tsk)
{
	return tsk->trace & TSK_TRACE_FL_GRAPH;
}

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enum ftrace_dump_mode;

extern enum ftrace_dump_mode ftrace_dump_on_oops;
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#ifdef CONFIG_PREEMPT
#define INIT_TRACE_RECURSION		.trace_recursion = 0,
#endif

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#endif /* CONFIG_TRACING */

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#ifndef INIT_TRACE_RECURSION
#define INIT_TRACE_RECURSION
#endif
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#ifdef CONFIG_FTRACE_SYSCALLS

unsigned long arch_syscall_addr(int nr);

#endif /* CONFIG_FTRACE_SYSCALLS */

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#endif /* _LINUX_FTRACE_H */