perf: Fix task context scheduling

[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / include / linux / perf_event.h

/*
 * Performance events:
 *
 *    Copyright (C) 2008-2009, Thomas Gleixner <tglx@linutronix.de>
 *    Copyright (C) 2008-2009, Red Hat, Inc., Ingo Molnar
 *    Copyright (C) 2008-2009, Red Hat, Inc., Peter Zijlstra
 *
 * Data type definitions, declarations, prototypes.
 *
 *    Started by: Thomas Gleixner and Ingo Molnar
 *
 * For licencing details see kernel-base/COPYING
 */
#ifndef _LINUX_PERF_EVENT_H
#define _LINUX_PERF_EVENT_H

#include <linux/types.h>
#include <linux/ioctl.h>
#include <asm/byteorder.h>

/*
 * User-space ABI bits:
 */

/*
 * attr.type
 */
enum perf_type_id {
        PERF_TYPE_HARDWARE                      = 0,
        PERF_TYPE_SOFTWARE                      = 1,
        PERF_TYPE_TRACEPOINT                    = 2,
        PERF_TYPE_HW_CACHE                      = 3,
        PERF_TYPE_RAW                           = 4,
        PERF_TYPE_BREAKPOINT                    = 5,

        PERF_TYPE_MAX,                          /* non-ABI */
};

/*
 * Generalized performance event event_id types, used by the
 * attr.event_id parameter of the sys_perf_event_open()
 * syscall:
 */
enum perf_hw_id {
        /*
         * Common hardware events, generalized by the kernel:
         */
        PERF_COUNT_HW_CPU_CYCLES                = 0,
        PERF_COUNT_HW_INSTRUCTIONS              = 1,
        PERF_COUNT_HW_CACHE_REFERENCES          = 2,
        PERF_COUNT_HW_CACHE_MISSES              = 3,
        PERF_COUNT_HW_BRANCH_INSTRUCTIONS       = 4,
        PERF_COUNT_HW_BRANCH_MISSES             = 5,
        PERF_COUNT_HW_BUS_CYCLES                = 6,

        PERF_COUNT_HW_MAX,                      /* non-ABI */
};

/*
 * Generalized hardware cache events:
 *
 *       { L1-D, L1-I, LLC, ITLB, DTLB, BPU } x
 *       { read, write, prefetch } x
 *       { accesses, misses }
 */
enum perf_hw_cache_id {
        PERF_COUNT_HW_CACHE_L1D                 = 0,
        PERF_COUNT_HW_CACHE_L1I                 = 1,
        PERF_COUNT_HW_CACHE_LL                  = 2,
        PERF_COUNT_HW_CACHE_DTLB                = 3,
        PERF_COUNT_HW_CACHE_ITLB                = 4,
        PERF_COUNT_HW_CACHE_BPU                 = 5,

        PERF_COUNT_HW_CACHE_MAX,                /* non-ABI */
};

enum perf_hw_cache_op_id {
        PERF_COUNT_HW_CACHE_OP_READ             = 0,
        PERF_COUNT_HW_CACHE_OP_WRITE            = 1,
        PERF_COUNT_HW_CACHE_OP_PREFETCH         = 2,

        PERF_COUNT_HW_CACHE_OP_MAX,             /* non-ABI */
};

enum perf_hw_cache_op_result_id {
        PERF_COUNT_HW_CACHE_RESULT_ACCESS       = 0,
        PERF_COUNT_HW_CACHE_RESULT_MISS         = 1,

        PERF_COUNT_HW_CACHE_RESULT_MAX,         /* non-ABI */
};

/*
 * Special "software" events provided by the kernel, even if the hardware
 * does not support performance events. These events measure various
 * physical and sw events of the kernel (and allow the profiling of them as
 * well):
 */
enum perf_sw_ids {
        PERF_COUNT_SW_CPU_CLOCK                 = 0,
        PERF_COUNT_SW_TASK_CLOCK                = 1,
        PERF_COUNT_SW_PAGE_FAULTS               = 2,
        PERF_COUNT_SW_CONTEXT_SWITCHES          = 3,
        PERF_COUNT_SW_CPU_MIGRATIONS            = 4,
        PERF_COUNT_SW_PAGE_FAULTS_MIN           = 5,
        PERF_COUNT_SW_PAGE_FAULTS_MAJ           = 6,
        PERF_COUNT_SW_ALIGNMENT_FAULTS          = 7,
        PERF_COUNT_SW_EMULATION_FAULTS          = 8,

        PERF_COUNT_SW_MAX,                      /* non-ABI */
};

/*
 * Bits that can be set in attr.sample_type to request information
 * in the overflow packets.
 */
enum perf_event_sample_format {
        PERF_SAMPLE_IP                          = 1U << 0,
        PERF_SAMPLE_TID                         = 1U << 1,
        PERF_SAMPLE_TIME                        = 1U << 2,
        PERF_SAMPLE_ADDR                        = 1U << 3,
        PERF_SAMPLE_READ                        = 1U << 4,
        PERF_SAMPLE_CALLCHAIN                   = 1U << 5,
        PERF_SAMPLE_ID                          = 1U << 6,
        PERF_SAMPLE_CPU                         = 1U << 7,
        PERF_SAMPLE_PERIOD                      = 1U << 8,
        PERF_SAMPLE_STREAM_ID                   = 1U << 9,
        PERF_SAMPLE_RAW                         = 1U << 10,

        PERF_SAMPLE_MAX = 1U << 11,             /* non-ABI */
};

/*
 * The format of the data returned by read() on a perf event fd,
 * as specified by attr.read_format:
 *
 * struct read_format {
 *      { u64           value;
 *        { u64         time_enabled; } && PERF_FORMAT_ENABLED
 *        { u64         time_running; } && PERF_FORMAT_RUNNING
 *        { u64         id;           } && PERF_FORMAT_ID
 *      } && !PERF_FORMAT_GROUP
 *
 *      { u64           nr;
 *        { u64         time_enabled; } && PERF_FORMAT_ENABLED
 *        { u64         time_running; } && PERF_FORMAT_RUNNING
 *        { u64         value;
 *          { u64       id;           } && PERF_FORMAT_ID
 *        }             cntr[nr];
 *      } && PERF_FORMAT_GROUP
 * };
 */
enum perf_event_read_format {
        PERF_FORMAT_TOTAL_TIME_ENABLED          = 1U << 0,
        PERF_FORMAT_TOTAL_TIME_RUNNING          = 1U << 1,
        PERF_FORMAT_ID                          = 1U << 2,
        PERF_FORMAT_GROUP                       = 1U << 3,

        PERF_FORMAT_MAX = 1U << 4,              /* non-ABI */
};

#define PERF_ATTR_SIZE_VER0     64      /* sizeof first published struct */

/*
 * Hardware event_id to monitor via a performance monitoring event:
 */
struct perf_event_attr {

        /*
         * Major type: hardware/software/tracepoint/etc.
         */
        __u32                   type;

        /*
         * Size of the attr structure, for fwd/bwd compat.
         */
        __u32                   size;

        /*
         * Type specific configuration information.
         */
        __u64                   config;

        union {
                __u64           sample_period;
                __u64           sample_freq;
        };

        __u64                   sample_type;
        __u64                   read_format;

        __u64                   disabled       :  1, /* off by default        */
                                inherit        :  1, /* children inherit it   */
                                pinned         :  1, /* must always be on PMU */
                                exclusive      :  1, /* only group on PMU     */
                                exclude_user   :  1, /* don't count user      */
                                exclude_kernel :  1, /* ditto kernel          */
                                exclude_hv     :  1, /* ditto hypervisor      */
                                exclude_idle   :  1, /* don't count when idle */
                                mmap           :  1, /* include mmap data     */
                                comm           :  1, /* include comm data     */
                                freq           :  1, /* use freq, not period  */
                                inherit_stat   :  1, /* per task counts       */
                                enable_on_exec :  1, /* next exec enables     */
                                task           :  1, /* trace fork/exit       */
                                watermark      :  1, /* wakeup_watermark      */
                                /*
                                 * precise_ip:
                                 *
                                 *  0 - SAMPLE_IP can have arbitrary skid
                                 *  1 - SAMPLE_IP must have constant skid
                                 *  2 - SAMPLE_IP requested to have 0 skid
                                 *  3 - SAMPLE_IP must have 0 skid
                                 *
                                 *  See also PERF_RECORD_MISC_EXACT_IP
                                 */
                                precise_ip     :  2, /* skid constraint       */
                                mmap_data      :  1, /* non-exec mmap data    */
                                sample_id_all  :  1, /* sample_type all events */

                                __reserved_1   : 45;

        union {
                __u32           wakeup_events;    /* wakeup every n events */
                __u32           wakeup_watermark; /* bytes before wakeup   */
        };

        __u32                   bp_type;
        union {
                __u64           bp_addr;
                __u64           config1; /* extension of config */
        };
        union {
                __u64           bp_len;
                __u64           config2; /* extension of config1 */
        };
};

/*
 * Ioctls that can be done on a perf event fd:
 */
#define PERF_EVENT_IOC_ENABLE           _IO ('$', 0)
#define PERF_EVENT_IOC_DISABLE          _IO ('$', 1)
#define PERF_EVENT_IOC_REFRESH          _IO ('$', 2)
#define PERF_EVENT_IOC_RESET            _IO ('$', 3)
#define PERF_EVENT_IOC_PERIOD           _IOW('$', 4, __u64)
#define PERF_EVENT_IOC_SET_OUTPUT       _IO ('$', 5)
#define PERF_EVENT_IOC_SET_FILTER       _IOW('$', 6, char *)

enum perf_event_ioc_flags {
        PERF_IOC_FLAG_GROUP             = 1U << 0,
};

/*
 * Structure of the page that can be mapped via mmap
 */
struct perf_event_mmap_page {
        __u32   version;                /* version number of this structure */
        __u32   compat_version;         /* lowest version this is compat with */

        /*
         * Bits needed to read the hw events in user-space.
         *
         *   u32 seq;
         *   s64 count;
         *
         *   do {
         *     seq = pc->lock;
         *
         *     barrier()
         *     if (pc->index) {
         *       count = pmc_read(pc->index - 1);
         *       count += pc->offset;
         *     } else
         *       goto regular_read;
         *
         *     barrier();
         *   } while (pc->lock != seq);
         *
         * NOTE: for obvious reason this only works on self-monitoring
         *       processes.
         */
        __u32   lock;                   /* seqlock for synchronization */
        __u32   index;                  /* hardware event identifier */
        __s64   offset;                 /* add to hardware event value */
        __u64   time_enabled;           /* time event active */
        __u64   time_running;           /* time event on cpu */

                /*
                 * Hole for extension of the self monitor capabilities
                 */

        __u64   __reserved[123];        /* align to 1k */

        /*
         * Control data for the mmap() data buffer.
         *
         * User-space reading the @data_head value should issue an rmb(), on
         * SMP capable platforms, after reading this value -- see
         * perf_event_wakeup().
         *
         * When the mapping is PROT_WRITE the @data_tail value should be
         * written by userspace to reflect the last read data. In this case
         * the kernel will not over-write unread data.
         */
        __u64   data_head;              /* head in the data section */
        __u64   data_tail;              /* user-space written tail */
};

#define PERF_RECORD_MISC_CPUMODE_MASK           (7 << 0)
#define PERF_RECORD_MISC_CPUMODE_UNKNOWN        (0 << 0)
#define PERF_RECORD_MISC_KERNEL                 (1 << 0)
#define PERF_RECORD_MISC_USER                   (2 << 0)
#define PERF_RECORD_MISC_HYPERVISOR             (3 << 0)
#define PERF_RECORD_MISC_GUEST_KERNEL           (4 << 0)
#define PERF_RECORD_MISC_GUEST_USER             (5 << 0)

/*
 * Indicates that the content of PERF_SAMPLE_IP points to
 * the actual instruction that triggered the event. See also
 * perf_event_attr::precise_ip.
 */
#define PERF_RECORD_MISC_EXACT_IP               (1 << 14)
/*
 * Reserve the last bit to indicate some extended misc field
 */
#define PERF_RECORD_MISC_EXT_RESERVED           (1 << 15)

struct perf_event_header {
        __u32   type;
        __u16   misc;
        __u16   size;
};

enum perf_event_type {

        /*
         * If perf_event_attr.sample_id_all is set then all event types will
         * have the sample_type selected fields related to where/when
         * (identity) an event took place (TID, TIME, ID, CPU, STREAM_ID)
         * described in PERF_RECORD_SAMPLE below, it will be stashed just after
         * the perf_event_header and the fields already present for the existing
         * fields, i.e. at the end of the payload. That way a newer perf.data
         * file will be supported by older perf tools, with these new optional
         * fields being ignored.
         *
         * The MMAP events record the PROT_EXEC mappings so that we can
         * correlate userspace IPs to code. They have the following structure:
         *
         * struct {
         *      struct perf_event_header        header;
         *
         *      u32                             pid, tid;
         *      u64                             addr;
         *      u64                             len;
         *      u64                             pgoff;
         *      char                            filename[];
         * };
         */
        PERF_RECORD_MMAP                        = 1,

        /*
         * struct {
         *      struct perf_event_header        header;
         *      u64                             id;
         *      u64                             lost;
         * };
         */
        PERF_RECORD_LOST                        = 2,

        /*
         * struct {
         *      struct perf_event_header        header;
         *
         *      u32                             pid, tid;
         *      char                            comm[];
         * };
         */
        PERF_RECORD_COMM                        = 3,

        /*
         * struct {
         *      struct perf_event_header        header;
         *      u32                             pid, ppid;
         *      u32                             tid, ptid;
         *      u64                             time;
         * };
         */
        PERF_RECORD_EXIT                        = 4,

        /*
         * struct {
         *      struct perf_event_header        header;
         *      u64                             time;
         *      u64                             id;
         *      u64                             stream_id;
         * };
         */
        PERF_RECORD_THROTTLE                    = 5,
        PERF_RECORD_UNTHROTTLE                  = 6,

        /*
         * struct {
         *      struct perf_event_header        header;
         *      u32                             pid, ppid;
         *      u32                             tid, ptid;
         *      u64                             time;
         * };
         */
        PERF_RECORD_FORK                        = 7,

        /*
         * struct {
         *      struct perf_event_header        header;
         *      u32                             pid, tid;
         *
         *      struct read_format              values;
         * };
         */
        PERF_RECORD_READ                        = 8,

        /*
         * struct {
         *      struct perf_event_header        header;
         *
         *      { u64                   ip;       } && PERF_SAMPLE_IP
         *      { u32                   pid, tid; } && PERF_SAMPLE_TID
         *      { u64                   time;     } && PERF_SAMPLE_TIME
         *      { u64                   addr;     } && PERF_SAMPLE_ADDR
         *      { u64                   id;       } && PERF_SAMPLE_ID
         *      { u64                   stream_id;} && PERF_SAMPLE_STREAM_ID
         *      { u32                   cpu, res; } && PERF_SAMPLE_CPU
         *      { u64                   period;   } && PERF_SAMPLE_PERIOD
         *
         *      { struct read_format    values;   } && PERF_SAMPLE_READ
         *
         *      { u64                   nr,
         *        u64                   ips[nr];  } && PERF_SAMPLE_CALLCHAIN
         *
         *      #
         *      # The RAW record below is opaque data wrt the ABI
         *      #
         *      # That is, the ABI doesn't make any promises wrt to
         *      # the stability of its content, it may vary depending
         *      # on event, hardware, kernel version and phase of
         *      # the moon.
         *      #
         *      # In other words, PERF_SAMPLE_RAW contents are not an ABI.
         *      #
         *
         *      { u32                   size;
         *        char                  data[size];}&& PERF_SAMPLE_RAW
         * };
         */
        PERF_RECORD_SAMPLE                      = 9,

        PERF_RECORD_MAX,                        /* non-ABI */
};

enum perf_callchain_context {
        PERF_CONTEXT_HV                 = (__u64)-32,
        PERF_CONTEXT_KERNEL             = (__u64)-128,
        PERF_CONTEXT_USER               = (__u64)-512,

        PERF_CONTEXT_GUEST              = (__u64)-2048,
        PERF_CONTEXT_GUEST_KERNEL       = (__u64)-2176,
        PERF_CONTEXT_GUEST_USER         = (__u64)-2560,

        PERF_CONTEXT_MAX                = (__u64)-4095,
};

#define PERF_FLAG_FD_NO_GROUP   (1U << 0)
#define PERF_FLAG_FD_OUTPUT     (1U << 1)
#define PERF_FLAG_PID_CGROUP    (1U << 2) /* pid=cgroup id, per-cpu mode only */

#ifdef __KERNEL__
/*
 * Kernel-internal data types and definitions:
 */

#ifdef CONFIG_PERF_EVENTS
# include <linux/cgroup.h>
# include <asm/perf_event.h>
# include <asm/local64.h>
#endif

struct perf_guest_info_callbacks {
        int (*is_in_guest) (void);
        int (*is_user_mode) (void);
        unsigned long (*get_guest_ip) (void);
};

#ifdef CONFIG_HAVE_HW_BREAKPOINT
#include <asm/hw_breakpoint.h>
#endif

#include <linux/list.h>
#include <linux/mutex.h>
#include <linux/rculist.h>
#include <linux/rcupdate.h>
#include <linux/spinlock.h>
#include <linux/hrtimer.h>
#include <linux/fs.h>
#include <linux/pid_namespace.h>
#include <linux/workqueue.h>
#include <linux/ftrace.h>
#include <linux/cpu.h>
#include <linux/irq_work.h>
#include <linux/jump_label_ref.h>
#include <asm/atomic.h>
#include <asm/local.h>

#define PERF_MAX_STACK_DEPTH            255

struct perf_callchain_entry {
        __u64                           nr;
        __u64                           ip[PERF_MAX_STACK_DEPTH];
};

struct perf_raw_record {
        u32                             size;
        void                            *data;
};

struct perf_branch_entry {
        __u64                           from;
        __u64                           to;
        __u64                           flags;
};

struct perf_branch_stack {
        __u64                           nr;
        struct perf_branch_entry        entries[0];
};

struct task_struct;

/**
 * struct hw_perf_event - performance event hardware details:
 */
struct hw_perf_event {
#ifdef CONFIG_PERF_EVENTS
        union {
                struct { /* hardware */
                        u64             config;
                        u64             last_tag;
                        unsigned long   config_base;
                        unsigned long   event_base;
                        int             idx;
                        int             last_cpu;
                        unsigned int    extra_reg;
                        u64             extra_config;
                        int             extra_alloc;
                };
                struct { /* software */
                        struct hrtimer  hrtimer;
                };
#ifdef CONFIG_HAVE_HW_BREAKPOINT
                struct { /* breakpoint */
                        struct arch_hw_breakpoint       info;
                        struct list_head                bp_list;
                        /*
                         * Crufty hack to avoid the chicken and egg
                         * problem hw_breakpoint has with context
                         * creation and event initalization.
                         */
                        struct task_struct              *bp_target;
                };
#endif
        };
        int                             state;
        local64_t                       prev_count;
        u64                             sample_period;
        u64                             last_period;
        local64_t                       period_left;
        u64                             interrupts;

        u64                             freq_time_stamp;
        u64                             freq_count_stamp;
#endif
};

/*
 * hw_perf_event::state flags
 */
#define PERF_HES_STOPPED        0x01 /* the counter is stopped */
#define PERF_HES_UPTODATE       0x02 /* event->count up-to-date */
#define PERF_HES_ARCH           0x04

struct perf_event;

/*
 * Common implementation detail of pmu::{start,commit,cancel}_txn
 */
#define PERF_EVENT_TXN 0x1

/**
 * struct pmu - generic performance monitoring unit
 */
struct pmu {
        struct list_head                entry;

        struct device                   *dev;
        char                            *name;
        int                             type;

        int * __percpu                  pmu_disable_count;
        struct perf_cpu_context * __percpu pmu_cpu_context;
        int                             task_ctx_nr;

        /*
         * Fully disable/enable this PMU, can be used to protect from the PMI
         * as well as for lazy/batch writing of the MSRs.
         */
        void (*pmu_enable)              (struct pmu *pmu); /* optional */
        void (*pmu_disable)             (struct pmu *pmu); /* optional */

        /*
         * Try and initialize the event for this PMU.
         * Should return -ENOENT when the @event doesn't match this PMU.
         */
        int (*event_init)               (struct perf_event *event);

#define PERF_EF_START   0x01            /* start the counter when adding    */
#define PERF_EF_RELOAD  0x02            /* reload the counter when starting */
#define PERF_EF_UPDATE  0x04            /* update the counter when stopping */

        /*
         * Adds/Removes a counter to/from the PMU, can be done inside
         * a transaction, see the ->*_txn() methods.
         */
        int  (*add)                     (struct perf_event *event, int flags);
        void (*del)                     (struct perf_event *event, int flags);

        /*
         * Starts/Stops a counter present on the PMU. The PMI handler
         * should stop the counter when perf_event_overflow() returns
         * !0. ->start() will be used to continue.
         */
        void (*start)                   (struct perf_event *event, int flags);
        void (*stop)                    (struct perf_event *event, int flags);

        /*
         * Updates the counter value of the event.
         */
        void (*read)                    (struct perf_event *event);

        /*
         * Group events scheduling is treated as a transaction, add
         * group events as a whole and perform one schedulability test.
         * If the test fails, roll back the whole group
         *
         * Start the transaction, after this ->add() doesn't need to
         * do schedulability tests.
         */
        void (*start_txn)       (struct pmu *pmu); /* optional */
        /*
         * If ->start_txn() disabled the ->add() schedulability test
         * then ->commit_txn() is required to perform one. On success
         * the transaction is closed. On error the transaction is kept
         * open until ->cancel_txn() is called.
         */
        int  (*commit_txn)      (struct pmu *pmu); /* optional */
        /*
         * Will cancel the transaction, assumes ->del() is called
         * for each successfull ->add() during the transaction.
         */
        void (*cancel_txn)      (struct pmu *pmu); /* optional */
};

/**
 * enum perf_event_active_state - the states of a event
 */
enum perf_event_active_state {
        PERF_EVENT_STATE_ERROR          = -2,
        PERF_EVENT_STATE_OFF            = -1,
        PERF_EVENT_STATE_INACTIVE       =  0,
        PERF_EVENT_STATE_ACTIVE         =  1,
};

struct file;

#define PERF_BUFFER_WRITABLE            0x01

struct perf_buffer {
        atomic_t                        refcount;
        struct rcu_head                 rcu_head;
#ifdef CONFIG_PERF_USE_VMALLOC
        struct work_struct              work;
        int                             page_order;     /* allocation order  */
#endif
        int                             nr_pages;       /* nr of data pages  */
        int                             writable;       /* are we writable   */

        atomic_t                        poll;           /* POLL_ for wakeups */

        local_t                         head;           /* write position    */
        local_t                         nest;           /* nested writers    */
        local_t                         events;         /* event limit       */
        local_t                         wakeup;         /* wakeup stamp      */
        local_t                         lost;           /* nr records lost   */

        long                            watermark;      /* wakeup watermark  */

        struct perf_event_mmap_page     *user_page;
        void                            *data_pages[0];
};

struct perf_sample_data;

typedef void (*perf_overflow_handler_t)(struct perf_event *, int,
                                        struct perf_sample_data *,
                                        struct pt_regs *regs);

enum perf_group_flag {
        PERF_GROUP_SOFTWARE = 0x1,
};

#define SWEVENT_HLIST_BITS      8
#define SWEVENT_HLIST_SIZE      (1 << SWEVENT_HLIST_BITS)

struct swevent_hlist {
        struct hlist_head       heads[SWEVENT_HLIST_SIZE];
        struct rcu_head         rcu_head;
};

#define PERF_ATTACH_CONTEXT     0x01
#define PERF_ATTACH_GROUP       0x02
#define PERF_ATTACH_TASK        0x04

#ifdef CONFIG_CGROUP_PERF
/*
 * perf_cgroup_info keeps track of time_enabled for a cgroup.
 * This is a per-cpu dynamically allocated data structure.
 */
struct perf_cgroup_info {
        u64 time;
        u64 timestamp;
};

struct perf_cgroup {
        struct cgroup_subsys_state css;
        struct perf_cgroup_info *info;  /* timing info, one per cpu */
};
#endif

/**
 * struct perf_event - performance event kernel representation:
 */
struct perf_event {
#ifdef CONFIG_PERF_EVENTS
        struct list_head                group_entry;
        struct list_head                event_entry;
        struct list_head                sibling_list;
        struct hlist_node               hlist_entry;
        int                             nr_siblings;
        int                             group_flags;
        struct perf_event               *group_leader;
        struct pmu                      *pmu;

        enum perf_event_active_state    state;
        unsigned int                    attach_state;
        local64_t                       count;
        atomic64_t                      child_count;

        /*
         * These are the total time in nanoseconds that the event
         * has been enabled (i.e. eligible to run, and the task has
         * been scheduled in, if this is a per-task event)
         * and running (scheduled onto the CPU), respectively.
         *
         * They are computed from tstamp_enabled, tstamp_running and
         * tstamp_stopped when the event is in INACTIVE or ACTIVE state.
         */
        u64                             total_time_enabled;
        u64                             total_time_running;

        /*
         * These are timestamps used for computing total_time_enabled
         * and total_time_running when the event is in INACTIVE or
         * ACTIVE state, measured in nanoseconds from an arbitrary point
         * in time.
         * tstamp_enabled: the notional time when the event was enabled
         * tstamp_running: the notional time when the event was scheduled on
         * tstamp_stopped: in INACTIVE state, the notional time when the
         *      event was scheduled off.
         */
        u64                             tstamp_enabled;
        u64                             tstamp_running;
        u64                             tstamp_stopped;

        /*
         * timestamp shadows the actual context timing but it can
         * be safely used in NMI interrupt context. It reflects the
         * context time as it was when the event was last scheduled in.
         *
         * ctx_time already accounts for ctx->timestamp. Therefore to
         * compute ctx_time for a sample, simply add perf_clock().
         */
        u64                             shadow_ctx_time;

        struct perf_event_attr          attr;
        u16                             header_size;
        u16                             id_header_size;
        u16                             read_size;
        struct hw_perf_event            hw;

        struct perf_event_context       *ctx;
        struct file                     *filp;

        /*
         * These accumulate total time (in nanoseconds) that children
         * events have been enabled and running, respectively.
         */
        atomic64_t                      child_total_time_enabled;
        atomic64_t                      child_total_time_running;

        /*
         * Protect attach/detach and child_list:
         */
        struct mutex                    child_mutex;
        struct list_head                child_list;
        struct perf_event               *parent;

        int                             oncpu;
        int                             cpu;

        struct list_head                owner_entry;
        struct task_struct              *owner;

        /* mmap bits */
        struct mutex                    mmap_mutex;
        atomic_t                        mmap_count;
        int                             mmap_locked;
        struct user_struct              *mmap_user;
        struct perf_buffer              *buffer;

        /* poll related */
        wait_queue_head_t               waitq;
        struct fasync_struct            *fasync;

        /* delayed work for NMIs and such */
        int                             pending_wakeup;
        int                             pending_kill;
        int                             pending_disable;
        struct irq_work                 pending;

        atomic_t                        event_limit;

        void (*destroy)(struct perf_event *);
        struct rcu_head                 rcu_head;

        struct pid_namespace            *ns;
        u64                             id;

        perf_overflow_handler_t         overflow_handler;

#ifdef CONFIG_EVENT_TRACING
        struct ftrace_event_call        *tp_event;
        struct event_filter             *filter;
#endif

#ifdef CONFIG_CGROUP_PERF
        struct perf_cgroup              *cgrp; /* cgroup event is attach to */
        int                             cgrp_defer_enabled;
#endif

#endif /* CONFIG_PERF_EVENTS */
};

enum perf_event_context_type {
        task_context,
        cpu_context,
};

/**
 * struct perf_event_context - event context structure
 *
 * Used as a container for task events and CPU events as well:
 */
struct perf_event_context {
        struct pmu                      *pmu;
        enum perf_event_context_type    type;
        /*
         * Protect the states of the events in the list,
         * nr_active, and the list:
         */
        raw_spinlock_t                  lock;
        /*
         * Protect the list of events.  Locking either mutex or lock
         * is sufficient to ensure the list doesn't change; to change
         * the list you need to lock both the mutex and the spinlock.
         */
        struct mutex                    mutex;

        struct list_head                pinned_groups;
        struct list_head                flexible_groups;
        struct list_head                event_list;
        int                             nr_events;
        int                             nr_active;
        int                             is_active;
        int                             nr_stat;
        int                             rotate_disable;
        atomic_t                        refcount;
        struct task_struct              *task;

        /*
         * Context clock, runs when context enabled.
         */
        u64                             time;
        u64                             timestamp;

        /*
         * These fields let us detect when two contexts have both
         * been cloned (inherited) from a common ancestor.
         */
        struct perf_event_context       *parent_ctx;
        u64                             parent_gen;
        u64                             generation;
        int                             pin_count;
        struct rcu_head                 rcu_head;
        int                             nr_cgroups; /* cgroup events present */
};

/*
 * Number of contexts where an event can trigger:
 *      task, softirq, hardirq, nmi.
 */
#define PERF_NR_CONTEXTS        4

/**
 * struct perf_event_cpu_context - per cpu event context structure
 */
struct perf_cpu_context {
        struct perf_event_context       ctx;
        struct perf_event_context       *task_ctx;
        int                             active_oncpu;
        int                             exclusive;
        struct list_head                rotation_list;
        int                             jiffies_interval;
        struct pmu                      *active_pmu;
        struct perf_cgroup              *cgrp;
};

struct perf_output_handle {
        struct perf_event               *event;
        struct perf_buffer              *buffer;
        unsigned long                   wakeup;
        unsigned long                   size;
        void                            *addr;
        int                             page;
        int                             nmi;
        int                             sample;
};

#ifdef CONFIG_PERF_EVENTS

extern int perf_pmu_register(struct pmu *pmu, char *name, int type);
extern void perf_pmu_unregister(struct pmu *pmu);

extern int perf_num_counters(void);
extern const char *perf_pmu_name(void);
extern void __perf_event_task_sched_in(struct task_struct *task);
extern void __perf_event_task_sched_out(struct task_struct *task, struct task_struct *next);
extern int perf_event_init_task(struct task_struct *child);
extern void perf_event_exit_task(struct task_struct *child);
extern void perf_event_free_task(struct task_struct *task);
extern void perf_event_delayed_put(struct task_struct *task);
extern void perf_event_print_debug(void);
extern void perf_pmu_disable(struct pmu *pmu);
extern void perf_pmu_enable(struct pmu *pmu);
extern int perf_event_task_disable(void);
extern int perf_event_task_enable(void);
extern void perf_event_update_userpage(struct perf_event *event);
extern int perf_event_release_kernel(struct perf_event *event);
extern struct perf_event *
perf_event_create_kernel_counter(struct perf_event_attr *attr,
                                int cpu,
                                struct task_struct *task,
                                perf_overflow_handler_t callback);
extern u64 perf_event_read_value(struct perf_event *event,
                                 u64 *enabled, u64 *running);

struct perf_sample_data {
        u64                             type;

        u64                             ip;
        struct {
                u32     pid;
                u32     tid;
        }                               tid_entry;
        u64                             time;
        u64                             addr;
        u64                             id;
        u64                             stream_id;
        struct {
                u32     cpu;
                u32     reserved;
        }                               cpu_entry;
        u64                             period;
        struct perf_callchain_entry     *callchain;
        struct perf_raw_record          *raw;
};

static inline
void perf_sample_data_init(struct perf_sample_data *data, u64 addr)
{
        data->addr = addr;
        data->raw  = NULL;
}

extern void perf_output_sample(struct perf_output_handle *handle,
                               struct perf_event_header *header,
                               struct perf_sample_data *data,
                               struct perf_event *event);
extern void perf_prepare_sample(struct perf_event_header *header,
                                struct perf_sample_data *data,
                                struct perf_event *event,
                                struct pt_regs *regs);

extern int perf_event_overflow(struct perf_event *event, int nmi,
                                 struct perf_sample_data *data,
                                 struct pt_regs *regs);

static inline bool is_sampling_event(struct perf_event *event)
{
        return event->attr.sample_period != 0;
}

/*
 * Return 1 for a software event, 0 for a hardware event
 */
static inline int is_software_event(struct perf_event *event)
{
        return event->pmu->task_ctx_nr == perf_sw_context;
}

extern atomic_t perf_swevent_enabled[PERF_COUNT_SW_MAX];

extern void __perf_sw_event(u32, u64, int, struct pt_regs *, u64);

#ifndef perf_arch_fetch_caller_regs
static inline void
perf_arch_fetch_caller_regs(struct pt_regs *regs, unsigned long ip) { }
#endif

/*
 * Take a snapshot of the regs. Skip ip and frame pointer to
 * the nth caller. We only need a few of the regs:
 * - ip for PERF_SAMPLE_IP
 * - cs for user_mode() tests
 * - bp for callchains
 * - eflags, for future purposes, just in case
 */
static inline void perf_fetch_caller_regs(struct pt_regs *regs)
{
        memset(regs, 0, sizeof(*regs));

        perf_arch_fetch_caller_regs(regs, CALLER_ADDR0);
}

static __always_inline void
perf_sw_event(u32 event_id, u64 nr, int nmi, struct pt_regs *regs, u64 addr)
{
        struct pt_regs hot_regs;

        JUMP_LABEL(&perf_swevent_enabled[event_id], have_event);
        return;

have_event:
        if (!regs) {
                perf_fetch_caller_regs(&hot_regs);
                regs = &hot_regs;
        }
        __perf_sw_event(event_id, nr, nmi, regs, addr);
}

extern atomic_t perf_sched_events;

static inline void perf_event_task_sched_in(struct task_struct *task)
{
        COND_STMT(&perf_sched_events, __perf_event_task_sched_in(task));
}

static inline
void perf_event_task_sched_out(struct task_struct *task, struct task_struct *next)
{
        perf_sw_event(PERF_COUNT_SW_CONTEXT_SWITCHES, 1, 1, NULL, 0);

        __perf_event_task_sched_out(task, next);
}

extern void perf_event_mmap(struct vm_area_struct *vma);
extern struct perf_guest_info_callbacks *perf_guest_cbs;
extern int perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *callbacks);
extern int perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks *callbacks);

extern void perf_event_comm(struct task_struct *tsk);
extern void perf_event_fork(struct task_struct *tsk);

/* Callchains */
DECLARE_PER_CPU(struct perf_callchain_entry, perf_callchain_entry);

extern void perf_callchain_user(struct perf_callchain_entry *entry,
                                struct pt_regs *regs);
extern void perf_callchain_kernel(struct perf_callchain_entry *entry,
                                  struct pt_regs *regs);


static inline void
perf_callchain_store(struct perf_callchain_entry *entry, u64 ip)
{
        if (entry->nr < PERF_MAX_STACK_DEPTH)
                entry->ip[entry->nr++] = ip;
}

extern int sysctl_perf_event_paranoid;
extern int sysctl_perf_event_mlock;
extern int sysctl_perf_event_sample_rate;

extern int perf_proc_update_handler(struct ctl_table *table, int write,
                void __user *buffer, size_t *lenp,
                loff_t *ppos);

static inline bool perf_paranoid_tracepoint_raw(void)
{
        return sysctl_perf_event_paranoid > -1;
}

static inline bool perf_paranoid_cpu(void)
{
        return sysctl_perf_event_paranoid > 0;
}

static inline bool perf_paranoid_kernel(void)
{
        return sysctl_perf_event_paranoid > 1;
}

extern void perf_event_init(void);
extern void perf_tp_event(u64 addr, u64 count, void *record,
                          int entry_size, struct pt_regs *regs,
                          struct hlist_head *head, int rctx);
extern void perf_bp_event(struct perf_event *event, void *data);

#ifndef perf_misc_flags
#define perf_misc_flags(regs)   (user_mode(regs) ? PERF_RECORD_MISC_USER : \
                                 PERF_RECORD_MISC_KERNEL)
#define perf_instruction_pointer(regs)  instruction_pointer(regs)
#endif

extern int perf_output_begin(struct perf_output_handle *handle,
                             struct perf_event *event, unsigned int size,
                             int nmi, int sample);
extern void perf_output_end(struct perf_output_handle *handle);
extern void perf_output_copy(struct perf_output_handle *handle,
                             const void *buf, unsigned int len);
extern int perf_swevent_get_recursion_context(void);
extern void perf_swevent_put_recursion_context(int rctx);
extern void perf_event_enable(struct perf_event *event);
extern void perf_event_disable(struct perf_event *event);
extern void perf_event_task_tick(void);
#else
static inline void
perf_event_task_sched_in(struct task_struct *task)                      { }
static inline void
perf_event_task_sched_out(struct task_struct *task,
                            struct task_struct *next)                   { }
static inline int perf_event_init_task(struct task_struct *child)       { return 0; }
static inline void perf_event_exit_task(struct task_struct *child)      { }
static inline void perf_event_free_task(struct task_struct *task)       { }
static inline void perf_event_delayed_put(struct task_struct *task)     { }
static inline void perf_event_print_debug(void)                         { }
static inline int perf_event_task_disable(void)                         { return -EINVAL; }
static inline int perf_event_task_enable(void)                          { return -EINVAL; }

static inline void
perf_sw_event(u32 event_id, u64 nr, int nmi,
                     struct pt_regs *regs, u64 addr)                    { }
static inline void
perf_bp_event(struct perf_event *event, void *data)                     { }

static inline int perf_register_guest_info_callbacks
(struct perf_guest_info_callbacks *callbacks) { return 0; }
static inline int perf_unregister_guest_info_callbacks
(struct perf_guest_info_callbacks *callbacks) { return 0; }

static inline void perf_event_mmap(struct vm_area_struct *vma)          { }
static inline void perf_event_comm(struct task_struct *tsk)             { }
static inline void perf_event_fork(struct task_struct *tsk)             { }
static inline void perf_event_init(void)                                { }
static inline int  perf_swevent_get_recursion_context(void)             { return -1; }
static inline void perf_swevent_put_recursion_context(int rctx)         { }
static inline void perf_event_enable(struct perf_event *event)          { }
static inline void perf_event_disable(struct perf_event *event)         { }
static inline void perf_event_task_tick(void)                           { }
#endif

#define perf_output_put(handle, x) \
        perf_output_copy((handle), &(x), sizeof(x))

/*
 * This has to have a higher priority than migration_notifier in sched.c.
 */
#define perf_cpu_notifier(fn)                                   \
do {                                                            \
        static struct notifier_block fn##_nb __cpuinitdata =    \
                { .notifier_call = fn, .priority = CPU_PRI_PERF }; \
        fn(&fn##_nb, (unsigned long)CPU_UP_PREPARE,             \
                (void *)(unsigned long)smp_processor_id());     \
        fn(&fn##_nb, (unsigned long)CPU_STARTING,               \
                (void *)(unsigned long)smp_processor_id());     \
        fn(&fn##_nb, (unsigned long)CPU_ONLINE,                 \
                (void *)(unsigned long)smp_processor_id());     \
        register_cpu_notifier(&fn##_nb);                        \
} while (0)

#endif /* __KERNEL__ */
#endif /* _LINUX_PERF_EVENT_H */