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32 results

button.h

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  • trace.h 19.59 KiB
    #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>
    #include <trace/kmemtrace.h>
    #include <trace/power.h>
    
    enum trace_type {
    	__TRACE_FIRST_TYPE = 0,
    
    	TRACE_FN,
    	TRACE_CTX,
    	TRACE_WAKE,
    	TRACE_STACK,
    	TRACE_PRINT,
    	TRACE_SPECIAL,
    	TRACE_MMIO_RW,
    	TRACE_MMIO_MAP,
    	TRACE_BRANCH,
    	TRACE_BOOT_CALL,
    	TRACE_BOOT_RET,
    	TRACE_GRAPH_RET,
    	TRACE_GRAPH_ENT,
    	TRACE_USER_STACK,
    	TRACE_HW_BRANCHES,
    	TRACE_KMEM_ALLOC,
    	TRACE_KMEM_FREE,
    	TRACE_POWER,
    	TRACE_BLK,
    
    	__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		flags;
    	unsigned char		preempt_count;
    	int			pid;
    	int			tgid;
    };
    
    /*
     * Function trace entry - function address and parent function addres:
     */
    struct ftrace_entry {
    	struct trace_entry	ent;
    	unsigned long		ip;
    	unsigned long		parent_ip;
    };
    
    /* Function call entry */
    struct ftrace_graph_ent_entry {
    	struct trace_entry		ent;
    	struct ftrace_graph_ent		graph_ent;
    };
    
    /* Function return entry */
    struct ftrace_graph_ret_entry {
    	struct trace_entry		ent;
    	struct ftrace_graph_ret		ret;
    };
    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];
    };
    
    struct userstack_entry {
    	struct trace_entry	ent;
    	unsigned long		caller[FTRACE_STACK_ENTRIES];
    };
    
    /*
     * ftrace_printk entry:
     */
    struct print_entry {
    	struct trace_entry	ent;
    	unsigned long		ip;
    	int			depth;
    	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_call {
    	struct trace_entry	ent;
    	struct boot_trace_call boot_call;
    };
    
    struct trace_boot_ret {
    	struct trace_entry	ent;
    	struct boot_trace_ret boot_ret;
    };
    
    #define TRACE_FUNC_SIZE 30
    #define TRACE_FILE_SIZE 20
    struct trace_branch {
    	struct trace_entry	ent;
    	unsigned	        line;
    	char			func[TRACE_FUNC_SIZE+1];
    	char			file[TRACE_FILE_SIZE+1];
    	char			correct;
    };
    
    struct hw_branch_entry {
    	struct trace_entry	ent;
    	u64			from;
    	u64			to;
    };
    
    struct trace_power {
    	struct trace_entry	ent;
    	struct power_trace	state_data;
    };
    
    struct kmemtrace_alloc_entry {
    	struct trace_entry	ent;
    	enum kmemtrace_type_id type_id;
    	unsigned long call_site;
    	const void *ptr;
    	size_t bytes_req;
    	size_t bytes_alloc;
    	gfp_t gfp_flags;
    	int node;
    };
    
    struct kmemtrace_free_entry {
    	struct trace_entry	ent;
    	enum kmemtrace_type_id type_id;
    	unsigned long call_site;
    	const void *ptr;
    };
    
    /*
     * 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
     */
    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,
    };
    
    #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 stack_entry, TRACE_STACK);	\
    		IF_ASSIGN(var, ent, struct userstack_entry, TRACE_USER_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_call, TRACE_BOOT_CALL);\
    		IF_ASSIGN(var, ent, struct trace_boot_ret, TRACE_BOOT_RET);\
    		IF_ASSIGN(var, ent, struct trace_branch, TRACE_BRANCH); \
    		IF_ASSIGN(var, ent, struct ftrace_graph_ent_entry,	\
    			  TRACE_GRAPH_ENT);		\
    		IF_ASSIGN(var, ent, struct ftrace_graph_ret_entry,	\
    			  TRACE_GRAPH_RET);		\
    		IF_ASSIGN(var, ent, struct hw_branch_entry, TRACE_HW_BRANCHES);\
     		IF_ASSIGN(var, ent, struct trace_power, TRACE_POWER); \
    		IF_ASSIGN(var, ent, struct kmemtrace_alloc_entry,	\
    			  TRACE_KMEM_ALLOC);	\
    		IF_ASSIGN(var, ent, struct kmemtrace_free_entry,	\
    			  TRACE_KMEM_FREE);	\
    		__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 */
    	TRACE_TYPE_NO_CONSUME	= 3	/* Handled but ask to not consume */
    };
    
    
    /*
     * An option specific to a tracer. This is a boolean value.
     * The bit is the bit index that sets its value on the
     * flags value in struct tracer_flags.
     */
    struct tracer_opt {
    	const char 	*name; /* Will appear on the trace_options file */
    	u32 		bit; /* Mask assigned in val field in tracer_flags */
    };
    
    /*
     * The set of specific options for a tracer. Your tracer
     * have to set the initial value of the flags val.
     */
    struct tracer_flags {
    	u32			val;
    	struct tracer_opt 	*opts;
    };
    
    /* Makes more easy to define a tracer opt */
    #define TRACER_OPT(s, b)	.name = #s, .bit = b
    
    
    /**
     * struct tracer - a specific tracer and its callbacks to interact with debugfs
     * @name: the name chosen to select it on the available_tracers file
     * @init: called when one switches to this tracer (echo name > current_tracer)
     * @reset: called when one switches to another tracer
     * @start: called when tracing is unpaused (echo 1 > tracing_enabled)
     * @stop: called when tracing is paused (echo 0 > tracing_enabled)
     * @open: called when the trace file is opened
     * @pipe_open: called when the trace_pipe file is opened
     * @wait_pipe: override how the user waits for traces on trace_pipe
     * @close: called when the trace file is released
     * @read: override the default read callback on trace_pipe
     * @splice_read: override the default splice_read callback on trace_pipe
     * @selftest: selftest to run on boot (see trace_selftest.c)
     * @print_headers: override the first lines that describe your columns
     * @print_line: callback that prints a trace
     * @set_flag: signals one of your private flags changed (trace_options file)
     * @flags: your private flags
     */
    struct tracer {
    	const char		*name;
    	int			(*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			(*wait_pipe)(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);
    	ssize_t			(*splice_read)(struct trace_iterator *iter,
    					       struct file *filp,
    					       loff_t *ppos,
    					       struct pipe_inode_info *pipe,
    					       size_t len,
    					       unsigned int flags);
    #ifdef CONFIG_FTRACE_STARTUP_TEST
    	int			(*selftest)(struct tracer *trace,
    					    struct trace_array *tr);
    #endif
    	void			(*print_header)(struct seq_file *m);
    	enum print_line_t	(*print_line)(struct trace_iterator *iter);
    	/* If you handled the flag setting, return 0 */
    	int			(*set_flag)(u32 old_flags, u32 bit, int set);
    	struct tracer		*next;
    	int			print_max;
    	struct tracer_flags 	*flags;
    	struct tracer_stat	*stats;
    };
    
    struct trace_seq {
    	unsigned char		buffer[PAGE_SIZE];
    	unsigned int		len;
    	unsigned int		readpos;
    };
    
    #define TRACE_PIPE_ALL_CPU	-1
    
    /*
     * 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;
    	int			cpu_file;
    	struct mutex		mutex;
    	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_var_t		started;
    };
    
    int tracer_init(struct tracer *t, struct trace_array *tr);
    int tracing_is_enabled(void);
    void trace_wake_up(void);
    void tracing_reset(struct trace_array *tr, int cpu);
    void tracing_reset_online_cpus(struct trace_array *tr);
    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 ring_buffer_event;
    
    struct ring_buffer_event *trace_buffer_lock_reserve(struct trace_array *tr,
    						    unsigned char type,
    						    unsigned long len,
    						    unsigned long flags,
    						    int pc);
    void trace_buffer_unlock_commit(struct trace_array *tr,
    				struct ring_buffer_event *event,
    				unsigned long flags, int pc);
    
    struct trace_entry *tracing_get_trace_entry(struct trace_array *tr,
    						struct trace_array_cpu *data);
    
    struct trace_entry *trace_find_next_entry(struct trace_iterator *iter,
    					  int *ent_cpu, u64 *ent_ts);
    
    void tracing_generic_entry_update(struct trace_entry *entry,
    				  unsigned long flags,
    				  int pc);
    
    void default_wait_pipe(struct trace_iterator *iter);
    void poll_wait_pipe(struct trace_iterator *iter);
    
    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 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 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,
    		    unsigned long ip,
    		    unsigned long parent_ip,
    		    unsigned long flags, int pc);
    
    void trace_graph_return(struct ftrace_graph_ret *trace);
    int trace_graph_entry(struct ftrace_graph_ent *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);
    
    void __trace_stack(struct trace_array *tr,
    		   unsigned long flags,
    		   int skip, int pc);
    
    extern cycle_t ftrace_now(int cpu);
    
    #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 */
    
    extern char *trace_find_cmdline(int pid);
    
    #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_function_graph(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);
    extern int trace_selftest_startup_branch(struct tracer *trace,
    					 struct trace_array *tr);
    #endif /* CONFIG_FTRACE_STARTUP_TEST */
    
    extern void *head_page(struct trace_array_cpu *data);
    extern long ns2usecs(cycle_t nsec);
    extern int
    trace_vprintk(unsigned long ip, int depth, const char *fmt, va_list args);
    
    extern unsigned long trace_flags;
    
    /* Standard output formatting function used for function return traces */
    #ifdef CONFIG_FUNCTION_GRAPH_TRACER
    extern enum print_line_t print_graph_function(struct trace_iterator *iter);
    
    #ifdef CONFIG_DYNAMIC_FTRACE
    /* TODO: make this variable */
    #define FTRACE_GRAPH_MAX_FUNCS		32
    extern int ftrace_graph_count;
    extern unsigned long ftrace_graph_funcs[FTRACE_GRAPH_MAX_FUNCS];
    
    static inline int ftrace_graph_addr(unsigned long addr)
    {
    	int i;
    
    	if (!ftrace_graph_count || test_tsk_trace_graph(current))
    		return 1;
    
    	for (i = 0; i < ftrace_graph_count; i++) {
    		if (addr == ftrace_graph_funcs[i])
    			return 1;
    	}
    
    	return 0;
    }
    #else
    static inline int ftrace_trace_addr(unsigned long addr)
    {
    	return 1;
    }
    static inline int ftrace_graph_addr(unsigned long addr)
    {
    	return 1;
    }
    #endif /* CONFIG_DYNAMIC_FTRACE */
    
    #else /* CONFIG_FUNCTION_GRAPH_TRACER */
    static inline enum print_line_t
    print_graph_function(struct trace_iterator *iter)
    {
    	return TRACE_TYPE_UNHANDLED;
    }
    #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
    
    extern struct pid *ftrace_pid_trace;
    
    static inline int ftrace_trace_task(struct task_struct *task)
    {
    	if (!ftrace_pid_trace)
    		return 1;
    
    	return test_tsk_trace_trace(task);
    }
    
    /*
     * 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_BRANCH		= 0x1000,
    	TRACE_ITER_ANNOTATE		= 0x2000,
    	TRACE_ITER_USERSTACKTRACE       = 0x4000,
    	TRACE_ITER_SYM_USEROBJ          = 0x8000,
    	TRACE_ITER_PRINTK_MSGONLY	= 0x10000,
    	TRACE_ITER_CONTEXT_INFO		= 0x20000 /* Print pid/cpu/time */
    };
    
    /*
     * 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_resched 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 are 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();
    }
    
    #ifdef CONFIG_BRANCH_TRACER
    extern int enable_branch_tracing(struct trace_array *tr);
    extern void disable_branch_tracing(void);
    static inline int trace_branch_enable(struct trace_array *tr)
    {
    	if (trace_flags & TRACE_ITER_BRANCH)
    		return enable_branch_tracing(tr);
    	return 0;
    }
    static inline void trace_branch_disable(void)
    {
    	/* due to races, always disable */
    	disable_branch_tracing();
    }
    #else
    static inline int trace_branch_enable(struct trace_array *tr)
    {
    	return 0;
    }
    static inline void trace_branch_disable(void)
    {
    }
    #endif /* CONFIG_BRANCH_TRACER */
    
    #endif /* _LINUX_KERNEL_TRACE_H */