root/include/linux/ftrace_event.h

INCLUDED FROM

DEFINITIONS

1. event
2. event
3. event
4. name
5. ftrace_trigger_soft_disabled
6. __event_trigger_test_discard
7. event_trigger_unlock_commit
8. event_trigger_unlock_commit_regs
9. perf_trace_buf_submit

#ifndef _LINUX_FTRACE_EVENT_H
#define _LINUX_FTRACE_EVENT_H

#include <linux/ring_buffer.h>
#include <linux/trace_seq.h>
#include <linux/percpu.h>
#include <linux/hardirq.h>
#include <linux/perf_event.h>
#include <linux/tracepoint.h>

struct trace_array;
struct trace_buffer;
struct tracer;
struct dentry;

struct trace_print_flags {
        unsigned long           mask;
        const char              *name;
};

struct trace_print_flags_u64 {
        unsigned long long      mask;
        const char              *name;
};

const char *ftrace_print_flags_seq(struct trace_seq *p, const char *delim,
                                   unsigned long flags,
                                   const struct trace_print_flags *flag_array);

const char *ftrace_print_symbols_seq(struct trace_seq *p, unsigned long val,
                                     const struct trace_print_flags *symbol_array);

#if BITS_PER_LONG == 32
const char *ftrace_print_symbols_seq_u64(struct trace_seq *p,
                                         unsigned long long val,
                                         const struct trace_print_flags_u64
                                                                 *symbol_array);
#endif

const char *ftrace_print_bitmask_seq(struct trace_seq *p, void *bitmask_ptr,
                                     unsigned int bitmask_size);

const char *ftrace_print_hex_seq(struct trace_seq *p,
                                 const unsigned char *buf, int len);

struct trace_iterator;
struct trace_event;

int ftrace_raw_output_prep(struct trace_iterator *iter,
                           struct trace_event *event);

/*
 * 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 short          type;
        unsigned char           flags;
        unsigned char           preempt_count;
        int                     pid;
};

#define FTRACE_MAX_EVENT                                                \
        ((1 << (sizeof(((struct trace_entry *)0)->type) * 8)) - 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;
        struct trace_buffer     *trace_buffer;
        void                    *private;
        int                     cpu_file;
        struct mutex            mutex;
        struct ring_buffer_iter **buffer_iter;
        unsigned long           iter_flags;

        /* trace_seq for __print_flags() and __print_symbolic() etc. */
        struct trace_seq        tmp_seq;

        cpumask_var_t           started;

        /* it's true when current open file is snapshot */
        bool                    snapshot;

        /* The below is zeroed out in pipe_read */
        struct trace_seq        seq;
        struct trace_entry      *ent;
        unsigned long           lost_events;
        int                     leftover;
        int                     ent_size;
        int                     cpu;
        u64                     ts;

        loff_t                  pos;
        long                    idx;

        /* All new field here will be zeroed out in pipe_read */
};

enum trace_iter_flags {
        TRACE_FILE_LAT_FMT      = 1,
        TRACE_FILE_ANNOTATE     = 2,
        TRACE_FILE_TIME_IN_NS   = 4,
};


typedef enum print_line_t (*trace_print_func)(struct trace_iterator *iter,
                                      int flags, struct trace_event *event);

struct trace_event_functions {
        trace_print_func        trace;
        trace_print_func        raw;
        trace_print_func        hex;
        trace_print_func        binary;
};

struct trace_event {
        struct hlist_node               node;
        struct list_head                list;
        int                             type;
        struct trace_event_functions    *funcs;
};

extern int register_ftrace_event(struct trace_event *event);
extern int unregister_ftrace_event(struct trace_event *event);

/* 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 */
};

void tracing_generic_entry_update(struct trace_entry *entry,
                                  unsigned long flags,
                                  int pc);
struct ftrace_event_file;

struct ring_buffer_event *
trace_event_buffer_lock_reserve(struct ring_buffer **current_buffer,
                                struct ftrace_event_file *ftrace_file,
                                int type, unsigned long len,
                                unsigned long flags, int pc);
struct ring_buffer_event *
trace_current_buffer_lock_reserve(struct ring_buffer **current_buffer,
                                  int type, unsigned long len,
                                  unsigned long flags, int pc);
void trace_current_buffer_unlock_commit(struct ring_buffer *buffer,
                                        struct ring_buffer_event *event,
                                        unsigned long flags, int pc);
void trace_buffer_unlock_commit(struct ring_buffer *buffer,
                                struct ring_buffer_event *event,
                                unsigned long flags, int pc);
void trace_buffer_unlock_commit_regs(struct ring_buffer *buffer,
                                     struct ring_buffer_event *event,
                                     unsigned long flags, int pc,
                                     struct pt_regs *regs);
void trace_current_buffer_discard_commit(struct ring_buffer *buffer,
                                         struct ring_buffer_event *event);

void tracing_record_cmdline(struct task_struct *tsk);

int ftrace_output_call(struct trace_iterator *iter, char *name, char *fmt, ...);

struct event_filter;

enum trace_reg {
        TRACE_REG_REGISTER,
        TRACE_REG_UNREGISTER,
#ifdef CONFIG_PERF_EVENTS
        TRACE_REG_PERF_REGISTER,
        TRACE_REG_PERF_UNREGISTER,
        TRACE_REG_PERF_OPEN,
        TRACE_REG_PERF_CLOSE,
        TRACE_REG_PERF_ADD,
        TRACE_REG_PERF_DEL,
#endif
};

struct ftrace_event_call;

struct ftrace_event_class {
        char                    *system;
        void                    *probe;
#ifdef CONFIG_PERF_EVENTS
        void                    *perf_probe;
#endif
        int                     (*reg)(struct ftrace_event_call *event,
                                       enum trace_reg type, void *data);
        int                     (*define_fields)(struct ftrace_event_call *);
        struct list_head        *(*get_fields)(struct ftrace_event_call *);
        struct list_head        fields;
        int                     (*raw_init)(struct ftrace_event_call *);
};

extern int ftrace_event_reg(struct ftrace_event_call *event,
                            enum trace_reg type, void *data);

int ftrace_output_event(struct trace_iterator *iter, struct ftrace_event_call *event,
                        char *fmt, ...);

int ftrace_event_define_field(struct ftrace_event_call *call,
                              char *type, int len, char *item, int offset,
                              int field_size, int sign, int filter);

struct ftrace_event_buffer {
        struct ring_buffer              *buffer;
        struct ring_buffer_event        *event;
        struct ftrace_event_file        *ftrace_file;
        void                            *entry;
        unsigned long                   flags;
        int                             pc;
};

void *ftrace_event_buffer_reserve(struct ftrace_event_buffer *fbuffer,
                                  struct ftrace_event_file *ftrace_file,
                                  unsigned long len);

void ftrace_event_buffer_commit(struct ftrace_event_buffer *fbuffer);

int ftrace_event_define_field(struct ftrace_event_call *call,
                              char *type, int len, char *item, int offset,
                              int field_size, int sign, int filter);

enum {
        TRACE_EVENT_FL_FILTERED_BIT,
        TRACE_EVENT_FL_CAP_ANY_BIT,
        TRACE_EVENT_FL_NO_SET_FILTER_BIT,
        TRACE_EVENT_FL_IGNORE_ENABLE_BIT,
        TRACE_EVENT_FL_WAS_ENABLED_BIT,
        TRACE_EVENT_FL_USE_CALL_FILTER_BIT,
        TRACE_EVENT_FL_TRACEPOINT_BIT,
};

/*
 * Event flags:
 *  FILTERED      - The event has a filter attached
 *  CAP_ANY       - Any user can enable for perf
 *  NO_SET_FILTER - Set when filter has error and is to be ignored
 *  IGNORE_ENABLE - For ftrace internal events, do not enable with debugfs file
 *  WAS_ENABLED   - Set and stays set when an event was ever enabled
 *                    (used for module unloading, if a module event is enabled,
 *                     it is best to clear the buffers that used it).
 *  USE_CALL_FILTER - For ftrace internal events, don't use file filter
 *  TRACEPOINT    - Event is a tracepoint
 */
enum {
        TRACE_EVENT_FL_FILTERED         = (1 << TRACE_EVENT_FL_FILTERED_BIT),
        TRACE_EVENT_FL_CAP_ANY          = (1 << TRACE_EVENT_FL_CAP_ANY_BIT),
        TRACE_EVENT_FL_NO_SET_FILTER    = (1 << TRACE_EVENT_FL_NO_SET_FILTER_BIT),
        TRACE_EVENT_FL_IGNORE_ENABLE    = (1 << TRACE_EVENT_FL_IGNORE_ENABLE_BIT),
        TRACE_EVENT_FL_WAS_ENABLED      = (1 << TRACE_EVENT_FL_WAS_ENABLED_BIT),
        TRACE_EVENT_FL_USE_CALL_FILTER  = (1 << TRACE_EVENT_FL_USE_CALL_FILTER_BIT),
        TRACE_EVENT_FL_TRACEPOINT       = (1 << TRACE_EVENT_FL_TRACEPOINT_BIT),
};

struct ftrace_event_call {
        struct list_head        list;
        struct ftrace_event_class *class;
        union {
                char                    *name;
                /* Set TRACE_EVENT_FL_TRACEPOINT flag when using "tp" */
                struct tracepoint       *tp;
        };
        struct trace_event      event;
        const char              *print_fmt;
        struct event_filter     *filter;
        void                    *mod;
        void                    *data;
        /*
         *   bit 0:             filter_active
         *   bit 1:             allow trace by non root (cap any)
         *   bit 2:             failed to apply filter
         *   bit 3:             ftrace internal event (do not enable)
         *   bit 4:             Event was enabled by module
         *   bit 5:             use call filter rather than file filter
         *   bit 6:             Event is a tracepoint
         */
        int                     flags; /* static flags of different events */

#ifdef CONFIG_PERF_EVENTS
        int                             perf_refcount;
        struct hlist_head __percpu      *perf_events;

        int     (*perf_perm)(struct ftrace_event_call *,
                             struct perf_event *);
#endif
};

static inline const char *
ftrace_event_name(struct ftrace_event_call *call)
{
        if (call->flags & TRACE_EVENT_FL_TRACEPOINT)
                return call->tp ? call->tp->name : NULL;
        else
                return call->name;
}

struct trace_array;
struct ftrace_subsystem_dir;

enum {
        FTRACE_EVENT_FL_ENABLED_BIT,
        FTRACE_EVENT_FL_RECORDED_CMD_BIT,
        FTRACE_EVENT_FL_FILTERED_BIT,
        FTRACE_EVENT_FL_NO_SET_FILTER_BIT,
        FTRACE_EVENT_FL_SOFT_MODE_BIT,
        FTRACE_EVENT_FL_SOFT_DISABLED_BIT,
        FTRACE_EVENT_FL_TRIGGER_MODE_BIT,
        FTRACE_EVENT_FL_TRIGGER_COND_BIT,
};

/*
 * Ftrace event file flags:
 *  ENABLED       - The event is enabled
 *  RECORDED_CMD  - The comms should be recorded at sched_switch
 *  FILTERED      - The event has a filter attached
 *  NO_SET_FILTER - Set when filter has error and is to be ignored
 *  SOFT_MODE     - The event is enabled/disabled by SOFT_DISABLED
 *  SOFT_DISABLED - When set, do not trace the event (even though its
 *                   tracepoint may be enabled)
 *  TRIGGER_MODE  - When set, invoke the triggers associated with the event
 *  TRIGGER_COND  - When set, one or more triggers has an associated filter
 */
enum {
        FTRACE_EVENT_FL_ENABLED         = (1 << FTRACE_EVENT_FL_ENABLED_BIT),
        FTRACE_EVENT_FL_RECORDED_CMD    = (1 << FTRACE_EVENT_FL_RECORDED_CMD_BIT),
        FTRACE_EVENT_FL_FILTERED        = (1 << FTRACE_EVENT_FL_FILTERED_BIT),
        FTRACE_EVENT_FL_NO_SET_FILTER   = (1 << FTRACE_EVENT_FL_NO_SET_FILTER_BIT),
        FTRACE_EVENT_FL_SOFT_MODE       = (1 << FTRACE_EVENT_FL_SOFT_MODE_BIT),
        FTRACE_EVENT_FL_SOFT_DISABLED   = (1 << FTRACE_EVENT_FL_SOFT_DISABLED_BIT),
        FTRACE_EVENT_FL_TRIGGER_MODE    = (1 << FTRACE_EVENT_FL_TRIGGER_MODE_BIT),
        FTRACE_EVENT_FL_TRIGGER_COND    = (1 << FTRACE_EVENT_FL_TRIGGER_COND_BIT),
};

struct ftrace_event_file {
        struct list_head                list;
        struct ftrace_event_call        *event_call;
        struct event_filter             *filter;
        struct dentry                   *dir;
        struct trace_array              *tr;
        struct ftrace_subsystem_dir     *system;
        struct list_head                triggers;

        /*
         * 32 bit flags:
         *   bit 0:             enabled
         *   bit 1:             enabled cmd record
         *   bit 2:             enable/disable with the soft disable bit
         *   bit 3:             soft disabled
         *   bit 4:             trigger enabled
         *
         * Note: The bits must be set atomically to prevent races
         * from other writers. Reads of flags do not need to be in
         * sync as they occur in critical sections. But the way flags
         * is currently used, these changes do not affect the code
         * except that when a change is made, it may have a slight
         * delay in propagating the changes to other CPUs due to
         * caching and such. Which is mostly OK ;-)
         */
        unsigned long           flags;
        atomic_t                sm_ref; /* soft-mode reference counter */
        atomic_t                tm_ref; /* trigger-mode reference counter */
};

#define __TRACE_EVENT_FLAGS(name, value)                                \
        static int __init trace_init_flags_##name(void)                 \
        {                                                               \
                event_##name.flags |= value;                            \
                return 0;                                               \
        }                                                               \
        early_initcall(trace_init_flags_##name);

#define __TRACE_EVENT_PERF_PERM(name, expr...)                          \
        static int perf_perm_##name(struct ftrace_event_call *tp_event, \
                                    struct perf_event *p_event)         \
        {                                                               \
                return ({ expr; });                                     \
        }                                                               \
        static int __init trace_init_perf_perm_##name(void)             \
        {                                                               \
                event_##name.perf_perm = &perf_perm_##name;             \
                return 0;                                               \
        }                                                               \
        early_initcall(trace_init_perf_perm_##name);

#define PERF_MAX_TRACE_SIZE     2048

#define MAX_FILTER_STR_VAL      256     /* Should handle KSYM_SYMBOL_LEN */

enum event_trigger_type {
        ETT_NONE                = (0),
        ETT_TRACE_ONOFF         = (1 << 0),
        ETT_SNAPSHOT            = (1 << 1),
        ETT_STACKTRACE          = (1 << 2),
        ETT_EVENT_ENABLE        = (1 << 3),
};

extern int filter_match_preds(struct event_filter *filter, void *rec);

extern int filter_check_discard(struct ftrace_event_file *file, void *rec,
                                struct ring_buffer *buffer,
                                struct ring_buffer_event *event);
extern int call_filter_check_discard(struct ftrace_event_call *call, void *rec,
                                     struct ring_buffer *buffer,
                                     struct ring_buffer_event *event);
extern enum event_trigger_type event_triggers_call(struct ftrace_event_file *file,
                                                   void *rec);
extern void event_triggers_post_call(struct ftrace_event_file *file,
                                     enum event_trigger_type tt);

/**
 * ftrace_trigger_soft_disabled - do triggers and test if soft disabled
 * @file: The file pointer of the event to test
 *
 * If any triggers without filters are attached to this event, they
 * will be called here. If the event is soft disabled and has no
 * triggers that require testing the fields, it will return true,
 * otherwise false.
 */
static inline bool
ftrace_trigger_soft_disabled(struct ftrace_event_file *file)
{
        unsigned long eflags = file->flags;

        if (!(eflags & FTRACE_EVENT_FL_TRIGGER_COND)) {
                if (eflags & FTRACE_EVENT_FL_TRIGGER_MODE)
                        event_triggers_call(file, NULL);
                if (eflags & FTRACE_EVENT_FL_SOFT_DISABLED)
                        return true;
        }
        return false;
}

/*
 * Helper function for event_trigger_unlock_commit{_regs}().
 * If there are event triggers attached to this event that requires
 * filtering against its fields, then they wil be called as the
 * entry already holds the field information of the current event.
 *
 * It also checks if the event should be discarded or not.
 * It is to be discarded if the event is soft disabled and the
 * event was only recorded to process triggers, or if the event
 * filter is active and this event did not match the filters.
 *
 * Returns true if the event is discarded, false otherwise.
 */
static inline bool
__event_trigger_test_discard(struct ftrace_event_file *file,
                             struct ring_buffer *buffer,
                             struct ring_buffer_event *event,
                             void *entry,
                             enum event_trigger_type *tt)
{
        unsigned long eflags = file->flags;

        if (eflags & FTRACE_EVENT_FL_TRIGGER_COND)
                *tt = event_triggers_call(file, entry);

        if (test_bit(FTRACE_EVENT_FL_SOFT_DISABLED_BIT, &file->flags))
                ring_buffer_discard_commit(buffer, event);
        else if (!filter_check_discard(file, entry, buffer, event))
                return false;

        return true;
}

/**
 * event_trigger_unlock_commit - handle triggers and finish event commit
 * @file: The file pointer assoctiated to the event
 * @buffer: The ring buffer that the event is being written to
 * @event: The event meta data in the ring buffer
 * @entry: The event itself
 * @irq_flags: The state of the interrupts at the start of the event
 * @pc: The state of the preempt count at the start of the event.
 *
 * This is a helper function to handle triggers that require data
 * from the event itself. It also tests the event against filters and
 * if the event is soft disabled and should be discarded.
 */
static inline void
event_trigger_unlock_commit(struct ftrace_event_file *file,
                            struct ring_buffer *buffer,
                            struct ring_buffer_event *event,
                            void *entry, unsigned long irq_flags, int pc)
{
        enum event_trigger_type tt = ETT_NONE;

        if (!__event_trigger_test_discard(file, buffer, event, entry, &tt))
                trace_buffer_unlock_commit(buffer, event, irq_flags, pc);

        if (tt)
                event_triggers_post_call(file, tt);
}

/**
 * event_trigger_unlock_commit_regs - handle triggers and finish event commit
 * @file: The file pointer assoctiated to the event
 * @buffer: The ring buffer that the event is being written to
 * @event: The event meta data in the ring buffer
 * @entry: The event itself
 * @irq_flags: The state of the interrupts at the start of the event
 * @pc: The state of the preempt count at the start of the event.
 *
 * This is a helper function to handle triggers that require data
 * from the event itself. It also tests the event against filters and
 * if the event is soft disabled and should be discarded.
 *
 * Same as event_trigger_unlock_commit() but calls
 * trace_buffer_unlock_commit_regs() instead of trace_buffer_unlock_commit().
 */
static inline void
event_trigger_unlock_commit_regs(struct ftrace_event_file *file,
                                 struct ring_buffer *buffer,
                                 struct ring_buffer_event *event,
                                 void *entry, unsigned long irq_flags, int pc,
                                 struct pt_regs *regs)
{
        enum event_trigger_type tt = ETT_NONE;

        if (!__event_trigger_test_discard(file, buffer, event, entry, &tt))
                trace_buffer_unlock_commit_regs(buffer, event,
                                                irq_flags, pc, regs);

        if (tt)
                event_triggers_post_call(file, tt);
}

enum {
        FILTER_OTHER = 0,
        FILTER_STATIC_STRING,
        FILTER_DYN_STRING,
        FILTER_PTR_STRING,
        FILTER_TRACE_FN,
};

extern int trace_event_raw_init(struct ftrace_event_call *call);
extern int trace_define_field(struct ftrace_event_call *call, const char *type,
                              const char *name, int offset, int size,
                              int is_signed, int filter_type);
extern int trace_add_event_call(struct ftrace_event_call *call);
extern int trace_remove_event_call(struct ftrace_event_call *call);

#define is_signed_type(type)    (((type)(-1)) < (type)1)

int trace_set_clr_event(const char *system, const char *event, int set);

/*
 * The double __builtin_constant_p is because gcc will give us an error
 * if we try to allocate the static variable to fmt if it is not a
 * constant. Even with the outer if statement optimizing out.
 */
#define event_trace_printk(ip, fmt, args...)                            \
do {                                                                    \
        __trace_printk_check_format(fmt, ##args);                       \
        tracing_record_cmdline(current);                                \
        if (__builtin_constant_p(fmt)) {                                \
                static const char *trace_printk_fmt                     \
                  __attribute__((section("__trace_printk_fmt"))) =      \
                        __builtin_constant_p(fmt) ? fmt : NULL;         \
                                                                        \
                __trace_bprintk(ip, trace_printk_fmt, ##args);          \
        } else                                                          \
                __trace_printk(ip, fmt, ##args);                        \
} while (0)

#ifdef CONFIG_PERF_EVENTS
struct perf_event;

DECLARE_PER_CPU(struct pt_regs, perf_trace_regs);

extern int  perf_trace_init(struct perf_event *event);
extern void perf_trace_destroy(struct perf_event *event);
extern int  perf_trace_add(struct perf_event *event, int flags);
extern void perf_trace_del(struct perf_event *event, int flags);
extern int  ftrace_profile_set_filter(struct perf_event *event, int event_id,
                                     char *filter_str);
extern void ftrace_profile_free_filter(struct perf_event *event);
extern void *perf_trace_buf_prepare(int size, unsigned short type,
                                    struct pt_regs *regs, int *rctxp);

static inline void
perf_trace_buf_submit(void *raw_data, int size, int rctx, u64 addr,
                       u64 count, struct pt_regs *regs, void *head,
                       struct task_struct *task)
{
        perf_tp_event(addr, count, raw_data, size, regs, head, rctx, task);
}
#endif

#endif /* _LINUX_FTRACE_EVENT_H */