/*
 * Performance events:
 *
 *    Copyright (C) 2008-2009, Thomas Gleixner <tglx@linutronix.de>
 *    Copyright (C) 2008-2011, Red Hat, Inc., Ingo Molnar
 *    Copyright (C) 2008-2011, 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 <uapi/linux/perf_event.h>
#include <uapi/linux/bpf_perf_event.h>

/*
 * Kernel-internal data types and definitions:
 */

#ifdef CONFIG_PERF_EVENTS
# 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);
        void                            (*handle_intel_pt_intr)(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/static_key.h>
#include <linux/jump_label_ratelimit.h>
#include <linux/atomic.h>
#include <linux/sysfs.h>
#include <linux/perf_regs.h>
#include <linux/cgroup.h>
#include <linux/refcount.h>
#include <linux/security.h>
#include <linux/static_call.h>
#include <asm/local.h>

struct perf_callchain_entry {
        __u64                           nr;
        __u64                           ip[]; /* /proc/sys/kernel/perf_event_max_stack */
};

struct perf_callchain_entry_ctx {
        struct perf_callchain_entry *entry;
        u32                         max_stack;
        u32                         nr;
        short                       contexts;
        bool                        contexts_maxed;
};

typedef unsigned long (*perf_copy_f)(void *dst, const void *src,
                                     unsigned long off, unsigned long len);

struct perf_raw_frag {
        union {
                struct perf_raw_frag    *next;
                unsigned long           pad;
        };
        perf_copy_f                     copy;
        void                            *data;
        u32                             size;
} __packed;

struct perf_raw_record {
        struct perf_raw_frag            frag;
        u32                             size;
};

/*
 * branch stack layout:
 *  nr: number of taken branches stored in entries[]
 *  hw_idx: The low level index of raw branch records
 *          for the most recent branch.
 *          -1ULL means invalid/unknown.
 *
 * Note that nr can vary from sample to sample
 * branches (to, from) are stored from most recent
 * to least recent, i.e., entries[0] contains the most
 * recent branch.
 * The entries[] is an abstraction of raw branch records,
 * which may not be stored in age order in HW, e.g. Intel LBR.
 * The hw_idx is to expose the low level index of raw
 * branch record for the most recent branch aka entries[0].
 * The hw_idx index is between -1 (unknown) and max depth,
 * which can be retrieved in /sys/devices/cpu/caps/branches.
 * For the architectures whose raw branch records are
 * already stored in age order, the hw_idx should be 0.
 */
struct perf_branch_stack {
        __u64                           nr;
        __u64                           hw_idx;
        struct perf_branch_entry        entries[];
};

struct task_struct;

/*
 * extra PMU register associated with an event
 */
struct hw_perf_event_extra {
        u64             config; /* register value */
        unsigned int    reg;    /* register address or index */
        int             alloc;  /* extra register already allocated */
        int             idx;    /* index in shared_regs->regs[] */
};

/**
 * 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             event_base_rdpmc;
                        int             idx;
                        int             last_cpu;
                        int             flags;

                        struct hw_perf_event_extra extra_reg;
                        struct hw_perf_event_extra branch_reg;
                };
                struct { /* software */
                        struct hrtimer  hrtimer;
                };
                struct { /* tracepoint */
                        /* for tp_event->class */
                        struct list_head        tp_list;
                };
                struct { /* amd_power */
                        u64     pwr_acc;
                        u64     ptsc;
                };
#ifdef CONFIG_HAVE_HW_BREAKPOINT
                struct { /* breakpoint */
                        /*
                         * Crufty hack to avoid the chicken and egg
                         * problem hw_breakpoint has with context
                         * creation and event initalization.
                         */
                        struct arch_hw_breakpoint       info;
                        struct list_head                bp_list;
                };
#endif
                struct { /* amd_iommu */
                        u8      iommu_bank;
                        u8      iommu_cntr;
                        u16     padding;
                        u64     conf;
                        u64     conf1;
                };
        };
        /*
         * If the event is a per task event, this will point to the task in
         * question. See the comment in perf_event_alloc().
         */
        struct task_struct              *target;

        /*
         * PMU would store hardware filter configuration
         * here.
         */
        void                            *addr_filters;

        /* Last sync'ed generation of filters */
        unsigned long                   addr_filters_gen;

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

        int                             state;

        /*
         * The last observed hardware counter value, updated with a
         * local64_cmpxchg() such that pmu::read() can be called nested.
         */
        local64_t                       prev_count;

        /*
         * The period to start the next sample with.
         */
        u64                             sample_period;

        union {
                struct { /* Sampling */
                        /*
                         * The period we started this sample with.
                         */
                        u64                             last_period;

                        /*
                         * However much is left of the current period;
                         * note that this is a full 64bit value and
                         * allows for generation of periods longer
                         * than hardware might allow.
                         */
                        local64_t                       period_left;
                };
                struct { /* Topdown events counting for context switch */
                        u64                             saved_metric;
                        u64                             saved_slots;
                };
        };

        /*
         * State for throttling the event, see __perf_event_overflow() and
         * perf_adjust_freq_unthr_context().
         */
        u64                             interrupts_seq;
        u64                             interrupts;

        /*
         * State for freq target events, see __perf_event_overflow() and
         * perf_adjust_freq_unthr_context().
         */
        u64                             freq_time_stamp;
        u64                             freq_count_stamp;
#endif
};

struct perf_event;

/*
 * Common implementation detail of pmu::{start,commit,cancel}_txn
 */
#define PERF_PMU_TXN_ADD  0x1           /* txn to add/schedule event on PMU */
#define PERF_PMU_TXN_READ 0x2           /* txn to read event group from PMU */

/**
 * pmu::capabilities flags
 */
#define PERF_PMU_CAP_NO_INTERRUPT               0x0001
#define PERF_PMU_CAP_NO_NMI                     0x0002
#define PERF_PMU_CAP_AUX_NO_SG                  0x0004
#define PERF_PMU_CAP_EXTENDED_REGS              0x0008
#define PERF_PMU_CAP_EXCLUSIVE                  0x0010
#define PERF_PMU_CAP_ITRACE                     0x0020
#define PERF_PMU_CAP_HETEROGENEOUS_CPUS         0x0040
#define PERF_PMU_CAP_NO_EXCLUDE                 0x0080
#define PERF_PMU_CAP_AUX_OUTPUT                 0x0100
#define PERF_PMU_CAP_EXTENDED_HW_TYPE           0x0200

struct perf_output_handle;

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

        struct module                   *module;
        struct device                   *dev;
        const struct attribute_group    **attr_groups;
        const struct attribute_group    **attr_update;
        const char                      *name;
        int                             type;

        /*
         * various common per-pmu feature flags
         */
        int                             capabilities;

        int __percpu                    *pmu_disable_count;
        struct perf_cpu_context __percpu *pmu_cpu_context;
        atomic_t                        exclusive_cnt; /* < 0: cpu; > 0: tsk */
        int                             task_ctx_nr;
        int                             hrtimer_interval_ms;

        /* number of address filters this PMU can do */
        unsigned int                    nr_addr_filters;

        /*
         * 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.
         *
         * Returns:
         *  -ENOENT     -- @event is not for this PMU
         *
         *  -ENODEV     -- @event is for this PMU but PMU not present
         *  -EBUSY      -- @event is for this PMU but PMU temporarily unavailable
         *  -EINVAL     -- @event is for this PMU but @event is not valid
         *  -EOPNOTSUPP -- @event is for this PMU, @event is valid, but not supported
         *  -EACCES     -- @event is for this PMU, @event is valid, but no privileges
         *
         *  0           -- @event is for this PMU and valid
         *
         * Other error return values are allowed.
         */
        int (*event_init)               (struct perf_event *event);

        /*
         * Notification that the event was mapped or unmapped.  Called
         * in the context of the mapping task.
         */
        void (*event_mapped)            (struct perf_event *event, struct mm_struct *mm); /* optional */
        void (*event_unmapped)          (struct perf_event *event, struct mm_struct *mm); /* optional */

        /*
         * Flags for ->add()/->del()/ ->start()/->stop(). There are
         * matching hw_perf_event::state flags.
         */
#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.
         *
         * The add/del callbacks will reserve all hardware resources required
         * to service the event, this includes any counter constraint
         * scheduling etc.
         *
         * Called with IRQs disabled and the PMU disabled on the CPU the event
         * is on.
         *
         * ->add() called without PERF_EF_START should result in the same state
         *  as ->add() followed by ->stop().
         *
         * ->del() must always PERF_EF_UPDATE stop an event. If it calls
         *  ->stop() that must deal with already being stopped without
         *  PERF_EF_UPDATE.
         */
        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.
         *
         * Also used to change the sample period.
         *
         * Called with IRQs disabled and the PMU disabled on the CPU the event
         * is on -- will be called from NMI context with the PMU generates
         * NMIs.
         *
         * ->stop() with PERF_EF_UPDATE will read the counter and update
         *  period/count values like ->read() would.
         *
         * ->start() with PERF_EF_RELOAD will reprogram the counter
         *  value, must be preceded by a ->stop() with PERF_EF_UPDATE.
         */
        void (*start)                   (struct perf_event *event, int flags);
        void (*stop)                    (struct perf_event *event, int flags);

        /*
         * Updates the counter value of the event.
         *
         * For sampling capable PMUs this will also update the software period
         * hw_perf_event::period_left field.
         */
        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.
         *
         * Optional.
         */
        void (*start_txn)               (struct pmu *pmu, unsigned int txn_flags);
        /*
         * 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.
         *
         * Optional.
         */
        int  (*commit_txn)              (struct pmu *pmu);
        /*
         * Will cancel the transaction, assumes ->del() is called
         * for each successful ->add() during the transaction.
         *
         * Optional.
         */
        void (*cancel_txn)              (struct pmu *pmu);

        /*
         * Will return the value for perf_event_mmap_page::index for this event,
         * if no implementation is provided it will default to: event->hw.idx + 1.
         */
        int (*event_idx)                (struct perf_event *event); /*optional */

        /*
         * context-switches callback
         */
        void (*sched_task)              (struct perf_event_context *ctx,
                                        bool sched_in);

        /*
         * Kmem cache of PMU specific data
         */
        struct kmem_cache               *task_ctx_cache;

        /*
         * PMU specific parts of task perf event context (i.e. ctx->task_ctx_data)
         * can be synchronized using this function. See Intel LBR callstack support
         * implementation and Perf core context switch handling callbacks for usage
         * examples.
         */
        void (*swap_task_ctx)           (struct perf_event_context *prev,
                                         struct perf_event_context *next);
                                        /* optional */

        /*
         * Set up pmu-private data structures for an AUX area
         */
        void *(*setup_aux)              (struct perf_event *event, void **pages,
                                         int nr_pages, bool overwrite);
                                        /* optional */

        /*
         * Free pmu-private AUX data structures
         */
        void (*free_aux)                (void *aux); /* optional */

        /*
         * Take a snapshot of the AUX buffer without touching the event
         * state, so that preempting ->start()/->stop() callbacks does
         * not interfere with their logic. Called in PMI context.
         *
         * Returns the size of AUX data copied to the output handle.
         *
         * Optional.
         */
        long (*snapshot_aux)            (struct perf_event *event,
                                         struct perf_output_handle *handle,
                                         unsigned long size);

        /*
         * Validate address range filters: make sure the HW supports the
         * requested configuration and number of filters; return 0 if the
         * supplied filters are valid, -errno otherwise.
         *
         * Runs in the context of the ioctl()ing process and is not serialized
         * with the rest of the PMU callbacks.
         */
        int (*addr_filters_validate)    (struct list_head *filters);
                                        /* optional */

        /*
         * Synchronize address range filter configuration:
         * translate hw-agnostic filters into hardware configuration in
         * event::hw::addr_filters.
         *
         * Runs as a part of filter sync sequence that is done in ->start()
         * callback by calling perf_event_addr_filters_sync().
         *
         * May (and should) traverse event::addr_filters::list, for which its
         * caller provides necessary serialization.
         */
        void (*addr_filters_sync)       (struct perf_event *event);
                                        /* optional */

        /*
         * Check if event can be used for aux_output purposes for
         * events of this PMU.
         *
         * Runs from perf_event_open(). Should return 0 for "no match"
         * or non-zero for "match".
         */
        int (*aux_output_match)         (struct perf_event *event);
                                        /* optional */

        /*
         * Filter events for PMU-specific reasons.
         */
        int (*filter_match)             (struct perf_event *event); /* optional */

        /*
         * Check period value for PERF_EVENT_IOC_PERIOD ioctl.
         */
        int (*check_period)             (struct perf_event *event, u64 value); /* optional */
};

enum perf_addr_filter_action_t {
        PERF_ADDR_FILTER_ACTION_STOP = 0,
        PERF_ADDR_FILTER_ACTION_START,
        PERF_ADDR_FILTER_ACTION_FILTER,
};

/**
 * struct perf_addr_filter - address range filter definition
 * @entry:      event's filter list linkage
 * @path:       object file's path for file-based filters
 * @offset:     filter range offset
 * @size:       filter range size (size==0 means single address trigger)
 * @action:     filter/start/stop
 *
 * This is a hardware-agnostic filter configuration as specified by the user.
 */
struct perf_addr_filter {
        struct list_head        entry;
        struct path             path;
        unsigned long           offset;
        unsigned long           size;
        enum perf_addr_filter_action_t  action;
};

/**
 * struct perf_addr_filters_head - container for address range filters
 * @list:       list of filters for this event
 * @lock:       spinlock that serializes accesses to the @list and event's
 *              (and its children's) filter generations.
 * @nr_file_filters:    number of file-based filters
 *
 * A child event will use parent's @list (and therefore @lock), so they are
 * bundled together; see perf_event_addr_filters().
 */
struct perf_addr_filters_head {
        struct list_head        list;
        raw_spinlock_t          lock;
        unsigned int            nr_file_filters;
};

struct perf_addr_filter_range {
        unsigned long           start;
        unsigned long           size;
};

/**
 * enum perf_event_state - the states of an event:
 */
enum perf_event_state {
        PERF_EVENT_STATE_DEAD           = -4,
        PERF_EVENT_STATE_EXIT           = -3,
        PERF_EVENT_STATE_ERROR          = -2,
        PERF_EVENT_STATE_OFF            = -1,
        PERF_EVENT_STATE_INACTIVE       =  0,
        PERF_EVENT_STATE_ACTIVE         =  1,
};

struct file;
struct perf_sample_data;

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

/*
 * Event capabilities. For event_caps and groups caps.
 *
 * PERF_EV_CAP_SOFTWARE: Is a software event.
 * PERF_EV_CAP_READ_ACTIVE_PKG: A CPU event (or cgroup event) that can be read
 * from any CPU in the package where it is active.
 * PERF_EV_CAP_SIBLING: An event with this flag must be a group sibling and
 * cannot be a group leader. If an event with this flag is detached from the
 * group it is scheduled out and moved into an unrecoverable ERROR state.
 */
#define PERF_EV_CAP_SOFTWARE            BIT(0)
#define PERF_EV_CAP_READ_ACTIVE_PKG     BIT(1)
#define PERF_EV_CAP_SIBLING             BIT(2)

#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
#define PERF_ATTACH_TASK_DATA   0x08
#define PERF_ATTACH_ITRACE      0x10
#define PERF_ATTACH_SCHED_CB    0x20
#define PERF_ATTACH_CHILD       0x40

struct perf_cgroup;
struct perf_buffer;

struct pmu_event_list {
        raw_spinlock_t          lock;
        struct list_head        list;
};

#define for_each_sibling_event(sibling, event)                  \
        if ((event)->group_leader == (event))                   \
                list_for_each_entry((sibling), &(event)->sibling_list, sibling_list)

/**
 * struct perf_event - performance event kernel representation:
 */
struct perf_event {
#ifdef CONFIG_PERF_EVENTS
        /*
         * entry onto perf_event_context::event_list;
         *   modifications require ctx->lock
         *   RCU safe iterations.
         */
        struct list_head                event_entry;

        /*
         * Locked for modification by both ctx->mutex and ctx->lock; holding
         * either sufficies for read.
         */
        struct list_head                sibling_list;
        struct list_head                active_list;
        /*
         * Node on the pinned or flexible tree located at the event context;
         */
        struct rb_node                  group_node;
        u64                             group_index;
        /*
         * We need storage to track the entries in perf_pmu_migrate_context; we
         * cannot use the event_entry because of RCU and we want to keep the
         * group in tact which avoids us using the other two entries.
         */
        struct list_head                migrate_entry;

        struct hlist_node               hlist_entry;
        struct list_head                active_entry;
        int                             nr_siblings;

        /* Not serialized. Only written during event initialization. */
        int                             event_caps;
        /* The cumulative AND of all event_caps for events in this group. */
        int                             group_caps;

        struct perf_event               *group_leader;
        struct pmu                      *pmu;
        void                            *pmu_private;

        enum perf_event_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.
         */
        u64                             total_time_enabled;
        u64                             total_time_running;
        u64                             tstamp;

        /*
         * 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,
         * or when ctx_sched_in failed to schedule the event because we
         * run out of PMC.
         *
         * 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;
        atomic_long_t                   refcount;

        /*
         * 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;

        struct perf_buffer              *rb;
        struct list_head                rb_entry;
        unsigned long                   rcu_batches;
        int                             rcu_pending;

        /* 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;
        unsigned long                   pending_addr;   /* SIGTRAP */
        struct irq_work                 pending;

        atomic_t                        event_limit;

        /* address range filters */
        struct perf_addr_filters_head   addr_filters;
        /* vma address array for file-based filders */
        struct perf_addr_filter_range   *addr_filter_ranges;
        unsigned long                   addr_filters_gen;

        /* for aux_output events */
        struct perf_event               *aux_event;

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

        struct pid_namespace            *ns;
        u64                             id;

        u64                             (*clock)(void);
        perf_overflow_handler_t         overflow_handler;
        void                            *overflow_handler_context;
#ifdef CONFIG_BPF_SYSCALL
        perf_overflow_handler_t         orig_overflow_handler;
        struct bpf_prog                 *prog;
        u64                             bpf_cookie;
#endif

#ifdef CONFIG_EVENT_TRACING
        struct trace_event_call         *tp_event;
        struct event_filter             *filter;
#ifdef CONFIG_FUNCTION_TRACER
        struct ftrace_ops               ftrace_ops;
#endif
#endif

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

#ifdef CONFIG_SECURITY
        void *security;
#endif
        struct list_head                sb_list;
#endif /* CONFIG_PERF_EVENTS */
};


struct perf_event_groups {
        struct rb_root  tree;
        u64             index;
};

/**
 * 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;
        /*
         * 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                active_ctx_list;
        struct perf_event_groups        pinned_groups;
        struct perf_event_groups        flexible_groups;
        struct list_head                event_list;

        struct list_head                pinned_active;
        struct list_head                flexible_active;

        int                             nr_events;
        int                             nr_active;
        int                             is_active;
        int                             nr_stat;
        int                             nr_freq;
        int                             rotate_disable;
        /*
         * Set when nr_events != nr_active, except tolerant to events not
         * necessary to be active due to scheduling constraints, such as cgroups.
         */
        int                             rotate_necessary;
        refcount_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;
#ifdef CONFIG_CGROUP_PERF
        int                             nr_cgroups;      /* cgroup evts */
#endif
        void                            *task_ctx_data; /* pmu specific data */
        struct rcu_head                 rcu_head;
};

/*
 * 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;

        raw_spinlock_t                  hrtimer_lock;
        struct hrtimer                  hrtimer;
        ktime_t                         hrtimer_interval;
        unsigned int                    hrtimer_active;

#ifdef CONFIG_CGROUP_PERF
        struct perf_cgroup              *cgrp;
        struct list_head                cgrp_cpuctx_entry;
#endif

        struct list_head                sched_cb_entry;
        int                             sched_cb_usage;

        int                             online;
        /*
         * Per-CPU storage for iterators used in visit_groups_merge. The default
         * storage is of size 2 to hold the CPU and any CPU event iterators.
         */
        int                             heap_size;
        struct perf_event               **heap;
        struct perf_event               *heap_default[2];
};

struct perf_output_handle {
        struct perf_event               *event;
        struct perf_buffer              *rb;
        unsigned long                   wakeup;
        unsigned long                   size;
        u64                             aux_flags;
        union {
                void                    *addr;
                unsigned long           head;
        };
        int                             page;
};

struct bpf_perf_event_data_kern {
        bpf_user_pt_regs_t *regs;
        struct perf_sample_data *data;
        struct perf_event *event;
};

#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 __percpu *info;
};

/*
 * Must ensure cgroup is pinned (css_get) before calling
 * this function. In other words, we cannot call this function
 * if there is no cgroup event for the current CPU context.
 */
static inline struct perf_cgroup *
perf_cgroup_from_task(struct task_struct *task, struct perf_event_context *ctx)
{
        return container_of(task_css_check(task, perf_event_cgrp_id,
                                           ctx ? lockdep_is_held(&ctx->lock)
                                               : true),
                            struct perf_cgroup, css);
}
#endif /* CONFIG_CGROUP_PERF */

#ifdef CONFIG_PERF_EVENTS

extern void *perf_aux_output_begin(struct perf_output_handle *handle,
                                   struct perf_event *event);
extern void perf_aux_output_end(struct perf_output_handle *handle,
                                unsigned long size);
extern int perf_aux_output_skip(struct perf_output_handle *handle,
                                unsigned long size);
extern void *perf_get_aux(struct perf_output_handle *handle);
extern void perf_aux_output_flag(struct perf_output_handle *handle, u64 flags);
extern void perf_event_itrace_started(struct perf_event *event);

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

extern void __perf_event_task_sched_in(struct task_struct *prev,
                                       struct task_struct *task);
extern void __perf_event_task_sched_out(struct task_struct *prev,
                                        struct task_struct *next);
extern int perf_event_init_task(struct task_struct *child, u64 clone_flags);
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 struct file *perf_event_get(unsigned int fd);
extern const struct perf_event *perf_get_event(struct file *file);
extern const struct perf_event_attr *perf_event_attrs(struct perf_event *event);
extern void perf_event_print_debug(void);
extern void perf_pmu_disable(struct pmu *pmu);
extern void perf_pmu_enable(struct pmu *pmu);
extern void perf_sched_cb_dec(struct pmu *pmu);
extern void perf_sched_cb_inc(struct pmu *pmu);
extern int perf_event_task_disable(void);
extern int perf_event_task_enable(void);

extern void perf_pmu_resched(struct pmu *pmu);

extern int perf_event_refresh(struct perf_event *event, int refresh);
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,
                                void *context);
extern void perf_pmu_migrate_context(struct pmu *pmu,
                                int src_cpu, int dst_cpu);
int perf_event_read_local(struct perf_event *event, u64 *value,
                          u64 *enabled, u64 *running);
extern u64 perf_event_read_value(struct perf_event *event,
                                 u64 *enabled, u64 *running);


struct perf_sample_data {
        /*

         * Fields set by perf_sample_data_init(), group so as to
         * minimize the cachelines touched.
         */
        u64                             addr;
        struct perf_raw_record          *raw;
        struct perf_branch_stack        *br_stack;
        u64                             period;
        union perf_sample_weight        weight;
        u64                             txn;
        union  perf_mem_data_src        data_src;

        /*
         * The other fields, optionally {set,used} by
         * perf_{prepare,output}_sample().
         */
        u64                             type;
        u64                             ip;
        struct {
                u32     pid;
                u32     tid;
        }                               tid_entry;
        u64                             time;
        u64                             id;
        u64                             stream_id;
        struct {
                u32     cpu;
                u32     reserved;
        }                               cpu_entry;
        struct perf_callchain_entry     *callchain;
        u64                             aux_size;

        struct perf_regs                regs_user;
        struct perf_regs                regs_intr;
        u64                             stack_user_size;

        u64                             phys_addr;
        u64                             cgroup;
        u64                             data_page_size;
        u64                             code_page_size;
} ____cacheline_aligned;

/* default value for data source */
#define PERF_MEM_NA (PERF_MEM_S(OP, NA)   |\
                    PERF_MEM_S(LVL, NA)   |\
                    PERF_MEM_S(SNOOP, NA) |\
                    PERF_MEM_S(LOCK, NA)  |\
                    PERF_MEM_S(TLB, NA))

static inline void perf_sample_data_init(struct perf_sample_data *data,
                                         u64 addr, u64 period)
{
        /* remaining struct members initialized in perf_prepare_sample() */
        data->addr = addr;
        data->raw  = NULL;
        data->br_stack = NULL;
        data->period = period;
        data->weight.full = 0;
        data->data_src.val = PERF_MEM_NA;
        data->txn = 0;
}

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,
                                 struct perf_sample_data *data,
                                 struct pt_regs *regs);

extern void perf_event_output_forward(struct perf_event *event,
                                     struct perf_sample_data *data,
                                     struct pt_regs *regs);
extern void perf_event_output_backward(struct perf_event *event,
                                       struct perf_sample_data *data,
                                       struct pt_regs *regs);
extern int perf_event_output(struct perf_event *event,
                             struct perf_sample_data *data,
                             struct pt_regs *regs);

static inline bool
is_default_overflow_handler(struct perf_event *event)
{
        if (likely(event->overflow_handler == perf_event_output_forward))
                return true;
        if (unlikely(event->overflow_handler == perf_event_output_backward))
                return true;
        return false;
}

extern void
perf_event_header__init_id(struct perf_event_header *header,
                           struct perf_sample_data *data,
                           struct perf_event *event);
extern void
perf_event__output_id_sample(struct perf_event *event,
                             struct perf_output_handle *handle,
                             struct perf_sample_data *sample);

extern void
perf_log_lost_samples(struct perf_event *event, u64 lost);

static inline bool event_has_any_exclude_flag(struct perf_event *event)
{
        struct perf_event_attr *attr = &event->attr;

        return attr->exclude_idle || attr->exclude_user ||
               attr->exclude_kernel || attr->exclude_hv ||
               attr->exclude_guest || attr->exclude_host;
}

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->event_caps & PERF_EV_CAP_SOFTWARE;
}

/*
 * Return 1 for event in sw context, 0 for event in hw context
 */
static inline int in_software_context(struct perf_event *event)
{
        return event->ctx->pmu->task_ctx_nr == perf_sw_context;
}

static inline int is_exclusive_pmu(struct pmu *pmu)
{
        return pmu->capabilities & PERF_PMU_CAP_EXCLUSIVE;
}

extern struct static_key perf_swevent_enabled[PERF_COUNT_SW_MAX];

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

/*
 * When generating a perf sample in-line, instead of from an interrupt /
 * exception, we lack a pt_regs. This is typically used from software events
 * like: SW_CONTEXT_SWITCHES, SW_MIGRATIONS and the tie-in with tracepoints.
 *
 * We typically don't need a full set, but (for x86) do require:
 * - ip for PERF_SAMPLE_IP
 * - cs for user_mode() tests
 * - sp for PERF_SAMPLE_CALLCHAIN
 * - eflags for MISC bits and CALLCHAIN (see: perf_hw_regs())
 *
 * NOTE: assumes @regs is otherwise already 0 filled; this is important for
 * things like PERF_SAMPLE_REGS_INTR.
 */
static inline void perf_fetch_caller_regs(struct pt_regs *regs)
{
        perf_arch_fetch_caller_regs(regs, CALLER_ADDR0);
}

static __always_inline void
perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
{
        if (static_key_false(&perf_swevent_enabled[event_id]))
                __perf_sw_event(event_id, nr, regs, addr);
}

DECLARE_PER_CPU(struct pt_regs, __perf_regs[4]);

/*
 * 'Special' version for the scheduler, it hard assumes no recursion,
 * which is guaranteed by us not actually scheduling inside other swevents
 * because those disable preemption.
 */
static __always_inline void __perf_sw_event_sched(u32 event_id, u64 nr, u64 addr)
{
        struct pt_regs *regs = this_cpu_ptr(&__perf_regs[0]);

        perf_fetch_caller_regs(regs);
        ___perf_sw_event(event_id, nr, regs, addr);
}

extern struct static_key_false perf_sched_events;

static __always_inline bool __perf_sw_enabled(int swevt)
{
        return static_key_false(&perf_swevent_enabled[swevt]);
}

static inline void perf_event_task_migrate(struct task_struct *task)
{
        if (__perf_sw_enabled(PERF_COUNT_SW_CPU_MIGRATIONS))
                task->sched_migrated = 1;
}

static inline void perf_event_task_sched_in(struct task_struct *prev,
                                            struct task_struct *task)
{
        if (static_branch_unlikely(&perf_sched_events))
                __perf_event_task_sched_in(prev, task);

        if (__perf_sw_enabled(PERF_COUNT_SW_CPU_MIGRATIONS) &&
            task->sched_migrated) {
                __perf_sw_event_sched(PERF_COUNT_SW_CPU_MIGRATIONS, 1, 0);
                task->sched_migrated = 0;
        }
}

static inline void perf_event_task_sched_out(struct task_struct *prev,
                                             struct task_struct *next)
{
        if (__perf_sw_enabled(PERF_COUNT_SW_CONTEXT_SWITCHES))
                __perf_sw_event_sched(PERF_COUNT_SW_CONTEXT_SWITCHES, 1, 0);

#ifdef CONFIG_CGROUP_PERF
        if (__perf_sw_enabled(PERF_COUNT_SW_CGROUP_SWITCHES) &&
            perf_cgroup_from_task(prev, NULL) !=
            perf_cgroup_from_task(next, NULL))
                __perf_sw_event_sched(PERF_COUNT_SW_CGROUP_SWITCHES, 1, 0);
#endif

        if (static_branch_unlikely(&perf_sched_events))
                __perf_event_task_sched_out(prev, next);
}

extern void perf_event_mmap(struct vm_area_struct *vma);

extern void perf_event_ksymbol(u16 ksym_type, u64 addr, u32 len,
                               bool unregister, const char *sym);
extern void perf_event_bpf_event(struct bpf_prog *prog,
                                 enum perf_bpf_event_type type,
                                 u16 flags);

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_exec(void);
extern void perf_event_comm(struct task_struct *tsk, bool exec);
extern void perf_event_namespaces(struct task_struct *tsk);
extern void perf_event_fork(struct task_struct *tsk);
extern void perf_event_text_poke(const void *addr,
                                 const void *old_bytes, size_t old_len,
                                 const void *new_bytes, size_t new_len);

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

extern void perf_callchain_user(struct perf_callchain_entry_ctx *entry, struct pt_regs *regs);
extern void perf_callchain_kernel(struct perf_callchain_entry_ctx *entry, struct pt_regs *regs);
extern struct perf_callchain_entry *
get_perf_callchain(struct pt_regs *regs, u32 init_nr, bool kernel, bool user,
                   u32 max_stack, bool crosstask, bool add_mark);
extern struct perf_callchain_entry *perf_callchain(struct perf_event *event, struct pt_regs *regs);
extern int get_callchain_buffers(int max_stack);
extern void put_callchain_buffers(void);
extern struct perf_callchain_entry *get_callchain_entry(int *rctx);
extern void put_callchain_entry(int rctx);

extern int sysctl_perf_event_max_stack;
extern int sysctl_perf_event_max_contexts_per_stack;

static inline int perf_callchain_store_context(struct perf_callchain_entry_ctx *ctx, u64 ip)
{
        if (ctx->contexts < sysctl_perf_event_max_contexts_per_stack) {
                struct perf_callchain_entry *entry = ctx->entry;
                entry->ip[entry->nr++] = ip;
                ++ctx->contexts;
                return 0;
        } else {
                ctx->contexts_maxed = true;
                return -1; /* no more room, stop walking the stack */
        }
}

static inline int perf_callchain_store(struct perf_callchain_entry_ctx *ctx, u64 ip)
{
        if (ctx->nr < ctx->max_stack && !ctx->contexts_maxed) {
                struct perf_callchain_entry *entry = ctx->entry;
                entry->ip[entry->nr++] = ip;
                ++ctx->nr;
                return 0;
        } else {
                return -1; /* no more room, stop walking the stack */
        }
}

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

extern void perf_sample_event_took(u64 sample_len_ns);

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

/* Access to perf_event_open(2) syscall. */
#define PERF_SECURITY_OPEN              0

/* Finer grained perf_event_open(2) access control. */
#define PERF_SECURITY_CPU               1
#define PERF_SECURITY_KERNEL            2
#define PERF_SECURITY_TRACEPOINT        3

static inline int perf_is_paranoid(void)
{
        return sysctl_perf_event_paranoid > -1;
}

static inline int perf_allow_kernel(struct perf_event_attr *attr)
{
        if (sysctl_perf_event_paranoid > 1 && !perfmon_capable())
                return -EACCES;

        return security_perf_event_open(attr, PERF_SECURITY_KERNEL);
}

static inline int perf_allow_cpu(struct perf_event_attr *attr)
{
        if (sysctl_perf_event_paranoid > 0 && !perfmon_capable())
                return -EACCES;

        return security_perf_event_open(attr, PERF_SECURITY_CPU);
}

static inline int perf_allow_tracepoint(struct perf_event_attr *attr)
{
        if (sysctl_perf_event_paranoid > -1 && !perfmon_capable())
                return -EPERM;

        return security_perf_event_open(attr, PERF_SECURITY_TRACEPOINT);
}

extern void perf_event_init(void);
extern void perf_tp_event(u16 event_type, u64 count, void *record,
                          int entry_size, struct pt_regs *regs,
                          struct hlist_head *head, int rctx,
                          struct task_struct *task);
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
#ifndef perf_arch_bpf_user_pt_regs
# define perf_arch_bpf_user_pt_regs(regs) regs
#endif

static inline bool has_branch_stack(struct perf_event *event)
{
        return event->attr.sample_type & PERF_SAMPLE_BRANCH_STACK;
}

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

static inline bool has_aux(struct perf_event *event)
{
        return event->pmu->setup_aux;
}

static inline bool is_write_backward(struct perf_event *event)
{
        return !!event->attr.write_backward;
}

static inline bool has_addr_filter(struct perf_event *event)
{
        return event->pmu->nr_addr_filters;
}

/*
 * An inherited event uses parent's filters
 */
static inline struct perf_addr_filters_head *
perf_event_addr_filters(struct perf_event *event)
{
        struct perf_addr_filters_head *ifh = &event->addr_filters;

        if (event->parent)
                ifh = &event->parent->addr_filters;

        return ifh;
}

extern void perf_event_addr_filters_sync(struct perf_event *event);
extern void perf_report_aux_output_id(struct perf_event *event, u64 hw_id);

extern int perf_output_begin(struct perf_output_handle *handle,
                             struct perf_sample_data *data,
                             struct perf_event *event, unsigned int size);
extern int perf_output_begin_forward(struct perf_output_handle *handle,
                                     struct perf_sample_data *data,
                                     struct perf_event *event,
                                     unsigned int size);
extern int perf_output_begin_backward(struct perf_output_handle *handle,
                                      struct perf_sample_data *data,
                                      struct perf_event *event,
                                      unsigned int size);

extern void perf_output_end(struct perf_output_handle *handle);
extern unsigned int perf_output_copy(struct perf_output_handle *handle,
                             const void *buf, unsigned int len);
extern unsigned int perf_output_skip(struct perf_output_handle *handle,
                                     unsigned int len);
extern long perf_output_copy_aux(struct perf_output_handle *aux_handle,
                                 struct perf_output_handle *handle,
                                 unsigned long from, unsigned long to);
extern int perf_swevent_get_recursion_context(void);
extern void perf_swevent_put_recursion_context(int rctx);
extern u64 perf_swevent_set_period(struct perf_event *event);
extern void perf_event_enable(struct perf_event *event);
extern void perf_event_disable(struct perf_event *event);
extern void perf_event_disable_local(struct perf_event *event);
extern void perf_event_disable_inatomic(struct perf_event *event);
extern void perf_event_task_tick(void);
extern int perf_event_account_interrupt(struct perf_event *event);
extern int perf_event_period(struct perf_event *event, u64 value);
extern u64 perf_event_pause(struct perf_event *event, bool reset);
#else /* !CONFIG_PERF_EVENTS: */
static inline void *
perf_aux_output_begin(struct perf_output_handle *handle,
                      struct perf_event *event)                         { return NULL; }
static inline void
perf_aux_output_end(struct perf_output_handle *handle, unsigned long size)
                                                                        { }
static inline int
perf_aux_output_skip(struct perf_output_handle *handle,
                     unsigned long size)                                { return -EINVAL; }
static inline void *
perf_get_aux(struct perf_output_handle *handle)                         { return NULL; }
static inline void
perf_event_task_migrate(struct task_struct *task)                       { }
static inline void
perf_event_task_sched_in(struct task_struct *prev,
                         struct task_struct *task)                      { }
static inline void
perf_event_task_sched_out(struct task_struct *prev,
                          struct task_struct *next)                     { }
static inline int perf_event_init_task(struct task_struct *child,
                                       u64 clone_flags)                 { 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 struct file *perf_event_get(unsigned int fd)      { return ERR_PTR(-EINVAL); }
static inline const struct perf_event *perf_get_event(struct file *file)
{
        return ERR_PTR(-EINVAL);
}
static inline const struct perf_event_attr *perf_event_attrs(struct perf_event *event)
{
        return ERR_PTR(-EINVAL);
}
static inline int perf_event_read_local(struct perf_event *event, u64 *value,
                                        u64 *enabled, u64 *running)
{
        return -EINVAL;
}
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 int perf_event_refresh(struct perf_event *event, int refresh)
{
        return -EINVAL;
}

static inline void
perf_sw_event(u32 event_id, u64 nr, 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)          { }

typedef int (perf_ksymbol_get_name_f)(char *name, int name_len, void *data);
static inline void perf_event_ksymbol(u16 ksym_type, u64 addr, u32 len,
                                      bool unregister, const char *sym) { }
static inline void perf_event_bpf_event(struct bpf_prog *prog,
                                        enum perf_bpf_event_type type,
                                        u16 flags)                      { }
static inline void perf_event_exec(void)                                { }
static inline void perf_event_comm(struct task_struct *tsk, bool exec)  { }
static inline void perf_event_namespaces(struct task_struct *tsk)       { }
static inline void perf_event_fork(struct task_struct *tsk)             { }
static inline void perf_event_text_poke(const void *addr,
                                        const void *old_bytes,
                                        size_t old_len,
                                        const void *new_bytes,
                                        size_t new_len)                 { }
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 u64 perf_swevent_set_period(struct perf_event *event)     { return 0; }
static inline void perf_event_enable(struct perf_event *event)          { }
static inline void perf_event_disable(struct perf_event *event)         { }
static inline int __perf_event_disable(void *info)                      { return -1; }
static inline void perf_event_task_tick(void)                           { }
static inline int perf_event_release_kernel(struct perf_event *event)   { return 0; }
static inline int perf_event_period(struct perf_event *event, u64 value)
{
        return -EINVAL;
}
static inline u64 perf_event_pause(struct perf_event *event, bool reset)
{
        return 0;
}
#endif

#if defined(CONFIG_PERF_EVENTS) && defined(CONFIG_CPU_SUP_INTEL)
extern void perf_restore_debug_store(void);
#else
static inline void perf_restore_debug_store(void)                       { }
#endif

static __always_inline bool perf_raw_frag_last(const struct perf_raw_frag *frag)
{
        return frag->pad < sizeof(u64);
}

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

struct perf_pmu_events_attr {
        struct device_attribute attr;
        u64 id;
        const char *event_str;
};

struct perf_pmu_events_ht_attr {
        struct device_attribute                 attr;
        u64                                     id;
        const char                              *event_str_ht;
        const char                              *event_str_noht;
};

struct perf_pmu_events_hybrid_attr {
        struct device_attribute                 attr;
        u64                                     id;
        const char                              *event_str;
        u64                                     pmu_type;
};

struct perf_pmu_format_hybrid_attr {
        struct device_attribute                 attr;
        u64                                     pmu_type;
};

ssize_t perf_event_sysfs_show(struct device *dev, struct device_attribute *attr,
                              char *page);

#define PMU_EVENT_ATTR(_name, _var, _id, _show)                         \
static struct perf_pmu_events_attr _var = {                             \
        .attr = __ATTR(_name, 0444, _show, NULL),                       \
        .id   =  _id,                                                   \
};

#define PMU_EVENT_ATTR_STRING(_name, _var, _str)                            \
static struct perf_pmu_events_attr _var = {                                 \
        .attr           = __ATTR(_name, 0444, perf_event_sysfs_show, NULL), \
        .id             = 0,                                                \
        .event_str      = _str,                                             \
};

#define PMU_EVENT_ATTR_ID(_name, _show, _id)                            \
        (&((struct perf_pmu_events_attr[]) {                            \
                { .attr = __ATTR(_name, 0444, _show, NULL),             \
                  .id = _id, }                                          \
        })[0].attr.attr)

#define PMU_FORMAT_ATTR(_name, _format)                                 \
static ssize_t                                                          \
_name##_show(struct device *dev,                                        \
                               struct device_attribute *attr,           \
                               char *page)                              \
{                                                                       \
        BUILD_BUG_ON(sizeof(_format) >= PAGE_SIZE);                     \
        return sprintf(page, _format "\n");                             \
}                                                                       \
                                                                        \
static struct device_attribute format_attr_##_name = __ATTR_RO(_name)

/* Performance counter hotplug functions */
#ifdef CONFIG_PERF_EVENTS
int perf_event_init_cpu(unsigned int cpu);
int perf_event_exit_cpu(unsigned int cpu);
#else
#define perf_event_init_cpu     NULL
#define perf_event_exit_cpu     NULL
#endif

extern void __weak arch_perf_update_userpage(struct perf_event *event,
                                             struct perf_event_mmap_page *userpg,
                                             u64 now);

#ifdef CONFIG_MMU
extern __weak u64 arch_perf_get_page_size(struct mm_struct *mm, unsigned long addr);
#endif

/*
 * Snapshot branch stack on software events.
 *
 * Branch stack can be very useful in understanding software events. For
 * example, when a long function, e.g. sys_perf_event_open, returns an
 * errno, it is not obvious why the function failed. Branch stack could
 * provide very helpful information in this type of scenarios.
 *
 * On software event, it is necessary to stop the hardware branch recorder
 * fast. Otherwise, the hardware register/buffer will be flushed with
 * entries of the triggering event. Therefore, static call is used to
 * stop the hardware recorder.
 */

/*
 * cnt is the number of entries allocated for entries.
 * Return number of entries copied to .
 */
typedef int (perf_snapshot_branch_stack_t)(struct perf_branch_entry *entries,
                                           unsigned int cnt);
DECLARE_STATIC_CALL(perf_snapshot_branch_stack, perf_snapshot_branch_stack_t);

#endif /* _LINUX_PERF_EVENT_H */