perf_counter: Fix race in attaching counters to tasks and exiting

[linux-2.6/mini2440.git] / include / linux / perf_counter.h

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

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

/*
 * User-space ABI bits:
 */

/*
 * hw_event.type
 */
enum perf_event_types {
        PERF_TYPE_HARDWARE              = 0,
        PERF_TYPE_SOFTWARE              = 1,
        PERF_TYPE_TRACEPOINT            = 2,

        /*
         * available TYPE space, raw is the max value.
         */

        PERF_TYPE_RAW                   = 128,
};

/*
 * Generalized performance counter event types, used by the hw_event.event_id
 * parameter of the sys_perf_counter_open() syscall:
 */
enum hw_event_ids {
        /*
         * Common hardware events, generalized by the kernel:
         */
        PERF_COUNT_CPU_CYCLES           = 0,
        PERF_COUNT_INSTRUCTIONS         = 1,
        PERF_COUNT_CACHE_REFERENCES     = 2,
        PERF_COUNT_CACHE_MISSES         = 3,
        PERF_COUNT_BRANCH_INSTRUCTIONS  = 4,
        PERF_COUNT_BRANCH_MISSES        = 5,
        PERF_COUNT_BUS_CYCLES           = 6,

        PERF_HW_EVENTS_MAX              = 7,
};

/*
 * Special "software" counters provided by the kernel, even if the hardware
 * does not support performance counters. These counters measure various
 * physical and sw events of the kernel (and allow the profiling of them as
 * well):
 */
enum sw_event_ids {
        PERF_COUNT_CPU_CLOCK            = 0,
        PERF_COUNT_TASK_CLOCK           = 1,
        PERF_COUNT_PAGE_FAULTS          = 2,
        PERF_COUNT_CONTEXT_SWITCHES     = 3,
        PERF_COUNT_CPU_MIGRATIONS       = 4,
        PERF_COUNT_PAGE_FAULTS_MIN      = 5,
        PERF_COUNT_PAGE_FAULTS_MAJ      = 6,

        PERF_SW_EVENTS_MAX              = 7,
};

#define __PERF_COUNTER_MASK(name)                       \
        (((1ULL << PERF_COUNTER_##name##_BITS) - 1) <<  \
         PERF_COUNTER_##name##_SHIFT)

#define PERF_COUNTER_RAW_BITS           1
#define PERF_COUNTER_RAW_SHIFT          63
#define PERF_COUNTER_RAW_MASK           __PERF_COUNTER_MASK(RAW)

#define PERF_COUNTER_CONFIG_BITS        63
#define PERF_COUNTER_CONFIG_SHIFT       0
#define PERF_COUNTER_CONFIG_MASK        __PERF_COUNTER_MASK(CONFIG)

#define PERF_COUNTER_TYPE_BITS          7
#define PERF_COUNTER_TYPE_SHIFT         56
#define PERF_COUNTER_TYPE_MASK          __PERF_COUNTER_MASK(TYPE)

#define PERF_COUNTER_EVENT_BITS         56
#define PERF_COUNTER_EVENT_SHIFT        0
#define PERF_COUNTER_EVENT_MASK         __PERF_COUNTER_MASK(EVENT)

/*
 * Bits that can be set in hw_event.record_type to request information
 * in the overflow packets.
 */
enum perf_counter_record_format {
        PERF_RECORD_IP                  = 1U << 0,
        PERF_RECORD_TID                 = 1U << 1,
        PERF_RECORD_TIME                = 1U << 2,
        PERF_RECORD_ADDR                = 1U << 3,
        PERF_RECORD_GROUP               = 1U << 4,
        PERF_RECORD_CALLCHAIN           = 1U << 5,
        PERF_RECORD_CONFIG              = 1U << 6,
        PERF_RECORD_CPU                 = 1U << 7,
};

/*
 * Bits that can be set in hw_event.read_format to request that
 * reads on the counter should return the indicated quantities,
 * in increasing order of bit value, after the counter value.
 */
enum perf_counter_read_format {
        PERF_FORMAT_TOTAL_TIME_ENABLED  =  1,
        PERF_FORMAT_TOTAL_TIME_RUNNING  =  2,
};

/*
 * Hardware event to monitor via a performance monitoring counter:
 */
struct perf_counter_hw_event {
        /*
         * The MSB of the config word signifies if the rest contains cpu
         * specific (raw) counter configuration data, if unset, the next
         * 7 bits are an event type and the rest of the bits are the event
         * identifier.
         */
        __u64                   config;

        union {
                __u64           irq_period;
                __u64           irq_freq;
        };

        __u32                   record_type;
        __u32                   read_format;

        __u64                   disabled       :  1, /* off by default        */
                                nmi            :  1, /* NMI sampling          */
                                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     */
                                munmap         :  1, /* include munmap data   */
                                comm           :  1, /* include comm data     */
                                freq           :  1, /* use freq, not period  */

                                __reserved_1   : 51;

        __u32                   wakeup_events;  /* wakeup every n events */
        __u32                   __reserved_2;

        __u64                   __reserved_3;
        __u64                   __reserved_4;
};

/*
 * Ioctls that can be done on a perf counter fd:
 */
#define PERF_COUNTER_IOC_ENABLE         _IOW('$', 0, u32)
#define PERF_COUNTER_IOC_DISABLE        _IOW('$', 1, u32)
#define PERF_COUNTER_IOC_REFRESH        _IOW('$', 2, u32)
#define PERF_COUNTER_IOC_RESET          _IOW('$', 3, u32)

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

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

        /*
         * Bits needed to read the hw counters 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 counter identifier */
        __s64   offset;                 /* add to hardware counter value */

        /*
         * Control data for the mmap() data buffer.
         *
         * User-space reading this value should issue an rmb(), on SMP capable
         * platforms, after reading this value -- see perf_counter_wakeup().
         */
        __u32   data_head;              /* head in the data section */
};

#define PERF_EVENT_MISC_CPUMODE_MASK    (3 << 0)
#define PERF_EVENT_MISC_CPUMODE_UNKNOWN (0 << 0)
#define PERF_EVENT_MISC_KERNEL          (1 << 0)
#define PERF_EVENT_MISC_USER            (2 << 0)
#define PERF_EVENT_MISC_HYPERVISOR      (3 << 0)
#define PERF_EVENT_MISC_OVERFLOW        (1 << 2)

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

enum perf_event_type {

        /*
         * 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_EVENT_MMAP                 = 1,
        PERF_EVENT_MUNMAP               = 2,

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

        /*
         * struct {
         *      struct perf_event_header        header;
         *      u64                             time;
         *      u64                             irq_period;
         * };
         */
        PERF_EVENT_PERIOD               = 4,

        /*
         * struct {
         *      struct perf_event_header        header;
         *      u64                             time;
         * };
         */
        PERF_EVENT_THROTTLE             = 5,
        PERF_EVENT_UNTHROTTLE           = 6,

        /*
         * When header.misc & PERF_EVENT_MISC_OVERFLOW the event_type field
         * will be PERF_RECORD_*
         *
         * struct {
         *      struct perf_event_header        header;
         *
         *      { u64                   ip;       } && PERF_RECORD_IP
         *      { u32                   pid, tid; } && PERF_RECORD_TID
         *      { u64                   time;     } && PERF_RECORD_TIME
         *      { u64                   addr;     } && PERF_RECORD_ADDR
         *      { u64                   config;   } && PERF_RECORD_CONFIG
         *      { u32                   cpu, res; } && PERF_RECORD_CPU
         *
         *      { u64                   nr;
         *        { u64 event, val; }   cnt[nr];  } && PERF_RECORD_GROUP
         *
         *      { u16                   nr,
         *                              hv,
         *                              kernel,
         *                              user;
         *        u64                   ips[nr];  } && PERF_RECORD_CALLCHAIN
         * };
         */
};

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

#ifdef CONFIG_PERF_COUNTERS
# include <asm/perf_counter.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 <asm/atomic.h>

struct task_struct;

static inline u64 perf_event_raw(struct perf_counter_hw_event *hw_event)
{
        return hw_event->config & PERF_COUNTER_RAW_MASK;
}

static inline u64 perf_event_config(struct perf_counter_hw_event *hw_event)
{
        return hw_event->config & PERF_COUNTER_CONFIG_MASK;
}

static inline u64 perf_event_type(struct perf_counter_hw_event *hw_event)
{
        return (hw_event->config & PERF_COUNTER_TYPE_MASK) >>
                PERF_COUNTER_TYPE_SHIFT;
}

static inline u64 perf_event_id(struct perf_counter_hw_event *hw_event)
{
        return hw_event->config & PERF_COUNTER_EVENT_MASK;
}

/**
 * struct hw_perf_counter - performance counter hardware details:
 */
struct hw_perf_counter {
#ifdef CONFIG_PERF_COUNTERS
        union {
                struct { /* hardware */
                        u64                             config;
                        unsigned long                   config_base;
                        unsigned long                   counter_base;
                        int                             nmi;
                        int                             idx;
                };
                union { /* software */
                        atomic64_t                      count;
                        struct hrtimer                  hrtimer;
                };
        };
        atomic64_t                      prev_count;
        u64                             irq_period;
        atomic64_t                      period_left;
        u64                             interrupts;
#endif
};

struct perf_counter;

/**
 * struct pmu - generic performance monitoring unit
 */
struct pmu {
        int (*enable)                   (struct perf_counter *counter);
        void (*disable)                 (struct perf_counter *counter);
        void (*read)                    (struct perf_counter *counter);
        void (*unthrottle)              (struct perf_counter *counter);
};

/**
 * enum perf_counter_active_state - the states of a counter
 */
enum perf_counter_active_state {
        PERF_COUNTER_STATE_ERROR        = -2,
        PERF_COUNTER_STATE_OFF          = -1,
        PERF_COUNTER_STATE_INACTIVE     =  0,
        PERF_COUNTER_STATE_ACTIVE       =  1,
};

struct file;

struct perf_mmap_data {
        struct rcu_head                 rcu_head;
        int                             nr_pages;       /* nr of data pages  */
        int                             nr_locked;      /* nr pages mlocked  */

        atomic_t                        poll;           /* POLL_ for wakeups */
        atomic_t                        head;           /* write position    */
        atomic_t                        events;         /* event limit       */

        atomic_t                        done_head;      /* completed head    */
        atomic_t                        lock;           /* concurrent writes */

        atomic_t                        wakeup;         /* needs a wakeup    */

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

struct perf_pending_entry {
        struct perf_pending_entry *next;
        void (*func)(struct perf_pending_entry *);
};

/**
 * struct perf_counter - performance counter kernel representation:
 */
struct perf_counter {
#ifdef CONFIG_PERF_COUNTERS
        struct list_head                list_entry;
        struct list_head                event_entry;
        struct list_head                sibling_list;
        int                             nr_siblings;
        struct perf_counter             *group_leader;
        const struct pmu                *pmu;

        enum perf_counter_active_state  state;
        enum perf_counter_active_state  prev_state;
        atomic64_t                      count;

        /*
         * These are the total time in nanoseconds that the counter
         * has been enabled (i.e. eligible to run, and the task has
         * been scheduled in, if this is a per-task counter)
         * and running (scheduled onto the CPU), respectively.
         *
         * They are computed from tstamp_enabled, tstamp_running and
         * tstamp_stopped when the counter 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 counter is in INACTIVE or
         * ACTIVE state, measured in nanoseconds from an arbitrary point
         * in time.
         * tstamp_enabled: the notional time when the counter was enabled
         * tstamp_running: the notional time when the counter was scheduled on
         * tstamp_stopped: in INACTIVE state, the notional time when the
         *      counter was scheduled off.
         */
        u64                             tstamp_enabled;
        u64                             tstamp_running;
        u64                             tstamp_stopped;

        struct perf_counter_hw_event    hw_event;
        struct hw_perf_counter          hw;

        struct perf_counter_context     *ctx;
        struct file                     *filp;

        /*
         * These accumulate total time (in nanoseconds) that children
         * counters 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_counter             *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_mmap_data           *data;

        /* 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 perf_pending_entry       pending;

        atomic_t                        event_limit;

        void (*destroy)(struct perf_counter *);
        struct rcu_head                 rcu_head;
#endif
};

/**
 * struct perf_counter_context - counter context structure
 *
 * Used as a container for task counters and CPU counters as well:
 */
struct perf_counter_context {
        /*
         * Protect the states of the counters in the list,
         * nr_active, and the list:
         */
        spinlock_t              lock;
        /*
         * Protect the list of counters.  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        counter_list;
        struct list_head        event_list;
        int                     nr_counters;
        int                     nr_active;
        int                     is_active;
        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_counter_context *parent_ctx;
        u64                     parent_gen;
        u64                     generation;
        struct rcu_head         rcu_head;
};

/**
 * struct perf_counter_cpu_context - per cpu counter context structure
 */
struct perf_cpu_context {
        struct perf_counter_context     ctx;
        struct perf_counter_context     *task_ctx;
        int                             active_oncpu;
        int                             max_pertask;
        int                             exclusive;

        /*
         * Recursion avoidance:
         *
         * task, softirq, irq, nmi context
         */
        int                     recursion[4];
};

#ifdef CONFIG_PERF_COUNTERS

/*
 * Set by architecture code:
 */
extern int perf_max_counters;

extern const struct pmu *hw_perf_counter_init(struct perf_counter *counter);

extern void perf_counter_task_sched_in(struct task_struct *task, int cpu);
extern void perf_counter_task_sched_out(struct task_struct *task,
                                        struct task_struct *next, int cpu);
extern void perf_counter_task_tick(struct task_struct *task, int cpu);
extern int perf_counter_init_task(struct task_struct *child);
extern void perf_counter_exit_task(struct task_struct *child);
extern void perf_counter_do_pending(void);
extern void perf_counter_print_debug(void);
extern void __perf_disable(void);
extern bool __perf_enable(void);
extern void perf_disable(void);
extern void perf_enable(void);
extern int perf_counter_task_disable(void);
extern int perf_counter_task_enable(void);
extern int hw_perf_group_sched_in(struct perf_counter *group_leader,
               struct perf_cpu_context *cpuctx,
               struct perf_counter_context *ctx, int cpu);
extern void perf_counter_update_userpage(struct perf_counter *counter);

extern int perf_counter_overflow(struct perf_counter *counter,
                                 int nmi, struct pt_regs *regs, u64 addr);
/*
 * Return 1 for a software counter, 0 for a hardware counter
 */
static inline int is_software_counter(struct perf_counter *counter)
{
        return !perf_event_raw(&counter->hw_event) &&
                perf_event_type(&counter->hw_event) != PERF_TYPE_HARDWARE;
}

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

extern void perf_counter_mmap(unsigned long addr, unsigned long len,
                              unsigned long pgoff, struct file *file);

extern void perf_counter_munmap(unsigned long addr, unsigned long len,
                                unsigned long pgoff, struct file *file);

extern void perf_counter_comm(struct task_struct *tsk);

#define MAX_STACK_DEPTH         255

struct perf_callchain_entry {
        u16     nr, hv, kernel, user;
        u64     ip[MAX_STACK_DEPTH];
};

extern struct perf_callchain_entry *perf_callchain(struct pt_regs *regs);

extern int sysctl_perf_counter_priv;
extern int sysctl_perf_counter_mlock;
extern int sysctl_perf_counter_limit;

extern void perf_counter_init(void);

#ifndef perf_misc_flags
#define perf_misc_flags(regs)   (user_mode(regs) ? PERF_EVENT_MISC_USER : \
                                 PERF_EVENT_MISC_KERNEL)
#define perf_instruction_pointer(regs)  instruction_pointer(regs)
#endif

#else
static inline void
perf_counter_task_sched_in(struct task_struct *task, int cpu)           { }
static inline void
perf_counter_task_sched_out(struct task_struct *task,
                            struct task_struct *next, int cpu)          { }
static inline void
perf_counter_task_tick(struct task_struct *task, int cpu)               { }
static inline int perf_counter_init_task(struct task_struct *child)     { return 0; }
static inline void perf_counter_exit_task(struct task_struct *child)    { }
static inline void perf_counter_do_pending(void)                        { }
static inline void perf_counter_print_debug(void)                       { }
static inline void perf_disable(void)                                   { }
static inline void perf_enable(void)                                    { }
static inline int perf_counter_task_disable(void)       { return -EINVAL; }
static inline int perf_counter_task_enable(void)        { return -EINVAL; }

static inline void
perf_swcounter_event(u32 event, u64 nr, int nmi,
                     struct pt_regs *regs, u64 addr)                    { }

static inline void
perf_counter_mmap(unsigned long addr, unsigned long len,
                  unsigned long pgoff, struct file *file)               { }

static inline void
perf_counter_munmap(unsigned long addr, unsigned long len,
                    unsigned long pgoff, struct file *file)             { }

static inline void perf_counter_comm(struct task_struct *tsk)           { }
static inline void perf_counter_init(void)                              { }
#endif

#endif /* __KERNEL__ */
#endif /* _LINUX_PERF_COUNTER_H */