include/linux/perf_counter.h

   1 /*
   2  *  Performance counters:
   3  *
   4  *   Copyright(C) 2008, Thomas Gleixner <tglx@linutronix.de>
   5  *   Copyright(C) 2008, Red Hat, Inc., Ingo Molnar
   6  *
   7  *  Data type definitions, declarations, prototypes.
   8  *
   9  *  Started by: Thomas Gleixner and Ingo Molnar
  10  *
  11  *  For licencing details see kernel-base/COPYING
  12  */
  13 #ifndef _LINUX_PERF_COUNTER_H
  14 #define _LINUX_PERF_COUNTER_H
  15
  16 #include <linux/types.h>
  17 #include <linux/ioctl.h>
  18 #include <asm/byteorder.h>
  19
  20 /*
  21  * User-space ABI bits:
  22  */
  23
  24 /*
  25  * attr.type
  26  */
  27 enum perf_event_types {
  28         PERF_TYPE_HARDWARE              = 0,
  29         PERF_TYPE_SOFTWARE              = 1,
  30         PERF_TYPE_TRACEPOINT            = 2,
  31
  32         /*
  33          * available TYPE space, raw is the max value.
  34          */
  35
  36         PERF_TYPE_RAW                   = 128,
  37 };
  38
  39 /*
  40  * Generalized performance counter event types, used by the attr.event_id
  41  * parameter of the sys_perf_counter_open() syscall:
  42  */
  43 enum attr_ids {
  44         /*
  45          * Common hardware events, generalized by the kernel:
  46          */
  47         PERF_COUNT_CPU_CYCLES           = 0,
  48         PERF_COUNT_INSTRUCTIONS         = 1,
  49         PERF_COUNT_CACHE_REFERENCES     = 2,
  50         PERF_COUNT_CACHE_MISSES         = 3,
  51         PERF_COUNT_BRANCH_INSTRUCTIONS  = 4,
  52         PERF_COUNT_BRANCH_MISSES        = 5,
  53         PERF_COUNT_BUS_CYCLES           = 6,
  54
  55         PERF_HW_EVENTS_MAX              = 7,
  56 };
  57
  58 /*
  59  * Special "software" counters provided by the kernel, even if the hardware
  60  * does not support performance counters. These counters measure various
  61  * physical and sw events of the kernel (and allow the profiling of them as
  62  * well):
  63  */
  64 enum sw_event_ids {
  65         PERF_COUNT_CPU_CLOCK            = 0,
  66         PERF_COUNT_TASK_CLOCK           = 1,
  67         PERF_COUNT_PAGE_FAULTS          = 2,
  68         PERF_COUNT_CONTEXT_SWITCHES     = 3,
  69         PERF_COUNT_CPU_MIGRATIONS       = 4,
  70         PERF_COUNT_PAGE_FAULTS_MIN      = 5,
  71         PERF_COUNT_PAGE_FAULTS_MAJ      = 6,
  72
  73         PERF_SW_EVENTS_MAX              = 7,
  74 };
  75
  76 #define __PERF_COUNTER_MASK(name)                       \
  77         (((1ULL << PERF_COUNTER_##name##_BITS) - 1) <<  \
  78          PERF_COUNTER_##name##_SHIFT)
  79
  80 #define PERF_COUNTER_RAW_BITS           1
  81 #define PERF_COUNTER_RAW_SHIFT          63
  82 #define PERF_COUNTER_RAW_MASK           __PERF_COUNTER_MASK(RAW)
  83
  84 #define PERF_COUNTER_CONFIG_BITS        63
  85 #define PERF_COUNTER_CONFIG_SHIFT       0
  86 #define PERF_COUNTER_CONFIG_MASK        __PERF_COUNTER_MASK(CONFIG)
  87
  88 #define PERF_COUNTER_TYPE_BITS          7
  89 #define PERF_COUNTER_TYPE_SHIFT         56
  90 #define PERF_COUNTER_TYPE_MASK          __PERF_COUNTER_MASK(TYPE)
  91
  92 #define PERF_COUNTER_EVENT_BITS         56
  93 #define PERF_COUNTER_EVENT_SHIFT        0
  94 #define PERF_COUNTER_EVENT_MASK         __PERF_COUNTER_MASK(EVENT)
  95
  96 /*
  97  * Bits that can be set in attr.sample_type to request information
  98  * in the overflow packets.
  99  */
 100 enum perf_counter_sample_format {
 101         PERF_SAMPLE_IP                  = 1U << 0,
 102         PERF_SAMPLE_TID                 = 1U << 1,
 103         PERF_SAMPLE_TIME                = 1U << 2,
 104         PERF_SAMPLE_ADDR                = 1U << 3,
 105         PERF_SAMPLE_GROUP               = 1U << 4,
 106         PERF_SAMPLE_CALLCHAIN           = 1U << 5,
 107         PERF_SAMPLE_ID                  = 1U << 6,
 108         PERF_SAMPLE_CPU                 = 1U << 7,
 109         PERF_SAMPLE_PERIOD              = 1U << 8,
 110 };
 111
 112 /*
 113  * Bits that can be set in attr.read_format to request that
 114  * reads on the counter should return the indicated quantities,
 115  * in increasing order of bit value, after the counter value.
 116  */
 117 enum perf_counter_read_format {
 118         PERF_FORMAT_TOTAL_TIME_ENABLED  =  1U << 0,
 119         PERF_FORMAT_TOTAL_TIME_RUNNING  =  1U << 1,
 120         PERF_FORMAT_ID                  =  1U << 2,
 121 };
 122
 123 /*
 124  * Hardware event to monitor via a performance monitoring counter:
 125  */
 126 struct perf_counter_attr {
 127         /*
 128          * The MSB of the config word signifies if the rest contains cpu
 129          * specific (raw) counter configuration data, if unset, the next
 130          * 7 bits are an event type and the rest of the bits are the event
 131          * identifier.
 132          */
 133         __u64                   config;
 134
 135         union {
 136                 __u64           sample_period;
 137                 __u64           sample_freq;
 138         };
 139
 140         __u64                   sample_type;
 141         __u64                   read_format;
 142
 143         __u64                   disabled       :  1, /* off by default        */
 144                                 inherit        :  1, /* children inherit it   */
 145                                 pinned         :  1, /* must always be on PMU */
 146                                 exclusive      :  1, /* only group on PMU     */
 147                                 exclude_user   :  1, /* don't count user      */
 148                                 exclude_kernel :  1, /* ditto kernel          */
 149                                 exclude_hv     :  1, /* ditto hypervisor      */
 150                                 exclude_idle   :  1, /* don't count when idle */
 151                                 mmap           :  1, /* include mmap data     */
 152                                 comm           :  1, /* include comm data     */
 153                                 freq           :  1, /* use freq, not period  */
 154
 155                                 __reserved_1   : 53;
 156
 157         __u32                   wakeup_events;  /* wakeup every n events */
 158         __u32                   __reserved_2;
 159
 160         __u64                   __reserved_3;
 161         __u64                   __reserved_4;
 162 };
 163
 164 /*
 165  * Ioctls that can be done on a perf counter fd:
 166  */
 167 #define PERF_COUNTER_IOC_ENABLE         _IO ('$', 0)
 168 #define PERF_COUNTER_IOC_DISABLE        _IO ('$', 1)
 169 #define PERF_COUNTER_IOC_REFRESH        _IO ('$', 2)
 170 #define PERF_COUNTER_IOC_RESET          _IO ('$', 3)
 171 #define PERF_COUNTER_IOC_PERIOD         _IOW('$', 4, u64)
 172
 173 enum perf_counter_ioc_flags {
 174         PERF_IOC_FLAG_GROUP             = 1U << 0,
 175 };
 176
 177 /*
 178  * Structure of the page that can be mapped via mmap
 179  */
 180 struct perf_counter_mmap_page {
 181         __u32   version;                /* version number of this structure */
 182         __u32   compat_version;         /* lowest version this is compat with */
 183
 184         /*
 185          * Bits needed to read the hw counters in user-space.
 186          *
 187          *   u32 seq;
 188          *   s64 count;
 189          *
 190          *   do {
 191          *     seq = pc->lock;
 192          *
 193          *     barrier()
 194          *     if (pc->index) {
 195          *       count = pmc_read(pc->index - 1);
 196          *       count += pc->offset;
 197          *     } else
 198          *       goto regular_read;
 199          *
 200          *     barrier();
 201          *   } while (pc->lock != seq);
 202          *
 203          * NOTE: for obvious reason this only works on self-monitoring
 204          *       processes.
 205          */
 206         __u32   lock;                   /* seqlock for synchronization */
 207         __u32   index;                  /* hardware counter identifier */
 208         __s64   offset;                 /* add to hardware counter value */
 209
 210         /*
 211          * Control data for the mmap() data buffer.
 212          *
 213          * User-space reading this value should issue an rmb(), on SMP capable
 214          * platforms, after reading this value -- see perf_counter_wakeup().
 215          */
 216         __u64   data_head;              /* head in the data section */
 217 };
 218
 219 #define PERF_EVENT_MISC_CPUMODE_MASK    (3 << 0)
 220 #define PERF_EVENT_MISC_CPUMODE_UNKNOWN (0 << 0)
 221 #define PERF_EVENT_MISC_KERNEL          (1 << 0)
 222 #define PERF_EVENT_MISC_USER            (2 << 0)
 223 #define PERF_EVENT_MISC_HYPERVISOR      (3 << 0)
 224 #define PERF_EVENT_MISC_OVERFLOW        (1 << 2)
 225
 226 struct perf_event_header {
 227         __u32   type;
 228         __u16   misc;
 229         __u16   size;
 230 };
 231
 232 enum perf_event_type {
 233
 234         /*
 235          * The MMAP events record the PROT_EXEC mappings so that we can
 236          * correlate userspace IPs to code. They have the following structure:
 237          *
 238          * struct {
 239          *      struct perf_event_header        header;
 240          *
 241          *      u32                             pid, tid;
 242          *      u64                             addr;
 243          *      u64                             len;
 244          *      u64                             pgoff;
 245          *      char                            filename[];
 246          * };
 247          */
 248         PERF_EVENT_MMAP                 = 1,
 249
 250         /*
 251          * struct {
 252          *      struct perf_event_header        header;
 253          *
 254          *      u32                             pid, tid;
 255          *      char                            comm[];
 256          * };
 257          */
 258         PERF_EVENT_COMM                 = 3,
 259
 260         /*
 261          * struct {
 262          *      struct perf_event_header        header;
 263          *      u64                             time;
 264          *      u64                             id;
 265          *      u64                             sample_period;
 266          * };
 267          */
 268         PERF_EVENT_PERIOD               = 4,
 269
 270         /*
 271          * struct {
 272          *      struct perf_event_header        header;
 273          *      u64                             time;
 274          * };
 275          */
 276         PERF_EVENT_THROTTLE             = 5,
 277         PERF_EVENT_UNTHROTTLE           = 6,
 278
 279         /*
 280          * struct {
 281          *      struct perf_event_header        header;
 282          *      u32                             pid, ppid;
 283          * };
 284          */
 285         PERF_EVENT_FORK                 = 7,
 286
 287         /*
 288          * When header.misc & PERF_EVENT_MISC_OVERFLOW the event_type field
 289          * will be PERF_RECORD_*
 290          *
 291          * struct {
 292          *      struct perf_event_header        header;
 293          *
 294          *      { u64                   ip;       } && PERF_RECORD_IP
 295          *      { u32                   pid, tid; } && PERF_RECORD_TID
 296          *      { u64                   time;     } && PERF_RECORD_TIME
 297          *      { u64                   addr;     } && PERF_RECORD_ADDR
 298          *      { u64                   config;   } && PERF_RECORD_CONFIG
 299          *      { u32                   cpu, res; } && PERF_RECORD_CPU
 300          *
 301          *      { u64                   nr;
 302          *        { u64 id, val; }      cnt[nr];  } && PERF_RECORD_GROUP
 303          *
 304          *      { u16                   nr,
 305          *                              hv,
 306          *                              kernel,
 307          *                              user;
 308          *        u64                   ips[nr];  } && PERF_RECORD_CALLCHAIN
 309          * };
 310          */
 311 };
 312
 313 #ifdef __KERNEL__
 314 /*
 315  * Kernel-internal data types and definitions:
 316  */
 317
 318 #ifdef CONFIG_PERF_COUNTERS
 319 # include <asm/perf_counter.h>
 320 #endif
 321
 322 #include <linux/list.h>
 323 #include <linux/mutex.h>
 324 #include <linux/rculist.h>
 325 #include <linux/rcupdate.h>
 326 #include <linux/spinlock.h>
 327 #include <linux/hrtimer.h>
 328 #include <linux/fs.h>
 329 #include <linux/pid_namespace.h>
 330 #include <asm/atomic.h>
 331
 332 struct task_struct;
 333
 334 static inline u64 perf_event_raw(struct perf_counter_attr *attr)
 335 {
 336         return attr->config & PERF_COUNTER_RAW_MASK;
 337 }
 338
 339 static inline u64 perf_event_config(struct perf_counter_attr *attr)
 340 {
 341         return attr->config & PERF_COUNTER_CONFIG_MASK;
 342 }
 343
 344 static inline u64 perf_event_type(struct perf_counter_attr *attr)
 345 {
 346         return (attr->config & PERF_COUNTER_TYPE_MASK) >>
 347                 PERF_COUNTER_TYPE_SHIFT;
 348 }
 349
 350 static inline u64 perf_event_id(struct perf_counter_attr *attr)
 351 {
 352         return attr->config & PERF_COUNTER_EVENT_MASK;
 353 }
 354
 355 /**
 356  * struct hw_perf_counter - performance counter hardware details:
 357  */
 358 struct hw_perf_counter {
 359 #ifdef CONFIG_PERF_COUNTERS
 360         union {
 361                 struct { /* hardware */
 362                         u64                             config;
 363                         unsigned long                   config_base;
 364                         unsigned long                   counter_base;
 365                         int                             idx;
 366                 };
 367                 union { /* software */
 368                         atomic64_t                      count;
 369                         struct hrtimer                  hrtimer;
 370                 };
 371         };
 372         atomic64_t                      prev_count;
 373         u64                             sample_period;
 374         atomic64_t                      period_left;
 375         u64                             interrupts;
 376
 377         u64                             freq_count;
 378         u64                             freq_interrupts;
 379 #endif
 380 };
 381
 382 struct perf_counter;
 383
 384 /**
 385  * struct pmu - generic performance monitoring unit
 386  */
 387 struct pmu {
 388         int (*enable)                   (struct perf_counter *counter);
 389         void (*disable)                 (struct perf_counter *counter);
 390         void (*read)                    (struct perf_counter *counter);
 391         void (*unthrottle)              (struct perf_counter *counter);
 392 };
 393
 394 /**
 395  * enum perf_counter_active_state - the states of a counter
 396  */
 397 enum perf_counter_active_state {
 398         PERF_COUNTER_STATE_ERROR        = -2,
 399         PERF_COUNTER_STATE_OFF          = -1,
 400         PERF_COUNTER_STATE_INACTIVE     =  0,
 401         PERF_COUNTER_STATE_ACTIVE       =  1,
 402 };
 403
 404 struct file;
 405
 406 struct perf_mmap_data {
 407         struct rcu_head                 rcu_head;
 408         int                             nr_pages;       /* nr of data pages  */
 409         int                             nr_locked;      /* nr pages mlocked  */
 410
 411         atomic_t                        poll;           /* POLL_ for wakeups */
 412         atomic_t                        events;         /* event limit       */
 413
 414         atomic_long_t                   head;           /* write position    */
 415         atomic_long_t                   done_head;      /* completed head    */
 416
 417         atomic_t                        lock;           /* concurrent writes */
 418
 419         atomic_t                        wakeup;         /* needs a wakeup    */
 420
 421         struct perf_counter_mmap_page   *user_page;
 422         void                            *data_pages[0];
 423 };
 424
 425 struct perf_pending_entry {
 426         struct perf_pending_entry *next;
 427         void (*func)(struct perf_pending_entry *);
 428 };
 429
 430 /**
 431  * struct perf_counter - performance counter kernel representation:
 432  */
 433 struct perf_counter {
 434 #ifdef CONFIG_PERF_COUNTERS
 435         struct list_head                list_entry;
 436         struct list_head                event_entry;
 437         struct list_head                sibling_list;
 438         int                             nr_siblings;
 439         struct perf_counter             *group_leader;
 440         const struct pmu                *pmu;
 441
 442         enum perf_counter_active_state  state;
 443         atomic64_t                      count;
 444
 445         /*
 446          * These are the total time in nanoseconds that the counter
 447          * has been enabled (i.e. eligible to run, and the task has
 448          * been scheduled in, if this is a per-task counter)
 449          * and running (scheduled onto the CPU), respectively.
 450          *
 451          * They are computed from tstamp_enabled, tstamp_running and
 452          * tstamp_stopped when the counter is in INACTIVE or ACTIVE state.
 453          */
 454         u64                             total_time_enabled;
 455         u64                             total_time_running;
 456
 457         /*
 458          * These are timestamps used for computing total_time_enabled
 459          * and total_time_running when the counter is in INACTIVE or
 460          * ACTIVE state, measured in nanoseconds from an arbitrary point
 461          * in time.
 462          * tstamp_enabled: the notional time when the counter was enabled
 463          * tstamp_running: the notional time when the counter was scheduled on
 464          * tstamp_stopped: in INACTIVE state, the notional time when the
 465          *      counter was scheduled off.
 466          */
 467         u64                             tstamp_enabled;
 468         u64                             tstamp_running;
 469         u64                             tstamp_stopped;
 470
 471         struct perf_counter_attr        attr;
 472         struct hw_perf_counter          hw;
 473
 474         struct perf_counter_context     *ctx;
 475         struct file                     *filp;
 476
 477         /*
 478          * These accumulate total time (in nanoseconds) that children
 479          * counters have been enabled and running, respectively.
 480          */
 481         atomic64_t                      child_total_time_enabled;
 482         atomic64_t                      child_total_time_running;
 483
 484         /*
 485          * Protect attach/detach and child_list:
 486          */
 487         struct mutex                    child_mutex;
 488         struct list_head                child_list;
 489         struct perf_counter             *parent;
 490
 491         int                             oncpu;
 492         int                             cpu;
 493
 494         struct list_head                owner_entry;
 495         struct task_struct              *owner;
 496
 497         /* mmap bits */
 498         struct mutex                    mmap_mutex;
 499         atomic_t                        mmap_count;
 500         struct perf_mmap_data           *data;
 501
 502         /* poll related */
 503         wait_queue_head_t               waitq;
 504         struct fasync_struct            *fasync;
 505
 506         /* delayed work for NMIs and such */
 507         int                             pending_wakeup;
 508         int                             pending_kill;
 509         int                             pending_disable;
 510         struct perf_pending_entry       pending;
 511
 512         atomic_t                        event_limit;
 513
 514         void (*destroy)(struct perf_counter *);
 515         struct rcu_head                 rcu_head;
 516
 517         struct pid_namespace            *ns;
 518         u64                             id;
 519 #endif
 520 };
 521
 522 /**
 523  * struct perf_counter_context - counter context structure
 524  *
 525  * Used as a container for task counters and CPU counters as well:
 526  */
 527 struct perf_counter_context {
 528         /*
 529          * Protect the states of the counters in the list,
 530          * nr_active, and the list:
 531          */
 532         spinlock_t              lock;
 533         /*
 534          * Protect the list of counters.  Locking either mutex or lock
 535          * is sufficient to ensure the list doesn't change; to change
 536          * the list you need to lock both the mutex and the spinlock.
 537          */
 538         struct mutex            mutex;
 539
 540         struct list_head        counter_list;
 541         struct list_head        event_list;
 542         int                     nr_counters;
 543         int                     nr_active;
 544         int                     is_active;
 545         atomic_t                refcount;
 546         struct task_struct      *task;
 547
 548         /*
 549          * Context clock, runs when context enabled.
 550          */
 551         u64                     time;
 552         u64                     timestamp;
 553
 554         /*
 555          * These fields let us detect when two contexts have both
 556          * been cloned (inherited) from a common ancestor.
 557          */
 558         struct perf_counter_context *parent_ctx;
 559         u64                     parent_gen;
 560         u64                     generation;
 561         int                     pin_count;
 562         struct rcu_head         rcu_head;
 563 };
 564
 565 /**
 566  * struct perf_counter_cpu_context - per cpu counter context structure
 567  */
 568 struct perf_cpu_context {
 569         struct perf_counter_context     ctx;
 570         struct perf_counter_context     *task_ctx;
 571         int                             active_oncpu;
 572         int                             max_pertask;
 573         int                             exclusive;
 574
 575         /*
 576          * Recursion avoidance:
 577          *
 578          * task, softirq, irq, nmi context
 579          */
 580         int                             recursion[4];
 581 };
 582
 583 #ifdef CONFIG_PERF_COUNTERS
 584
 585 /*
 586  * Set by architecture code:
 587  */
 588 extern int perf_max_counters;
 589
 590 extern const struct pmu *hw_perf_counter_init(struct perf_counter *counter);
 591
 592 extern void perf_counter_task_sched_in(struct task_struct *task, int cpu);
 593 extern void perf_counter_task_sched_out(struct task_struct *task,
 594                                         struct task_struct *next, int cpu);
 595 extern void perf_counter_task_tick(struct task_struct *task, int cpu);
 596 extern int perf_counter_init_task(struct task_struct *child);
 597 extern void perf_counter_exit_task(struct task_struct *child);
 598 extern void perf_counter_free_task(struct task_struct *task);
 599 extern void perf_counter_do_pending(void);
 600 extern void perf_counter_print_debug(void);
 601 extern void __perf_disable(void);
 602 extern bool __perf_enable(void);
 603 extern void perf_disable(void);
 604 extern void perf_enable(void);
 605 extern int perf_counter_task_disable(void);
 606 extern int perf_counter_task_enable(void);
 607 extern int hw_perf_group_sched_in(struct perf_counter *group_leader,
 608                struct perf_cpu_context *cpuctx,
 609                struct perf_counter_context *ctx, int cpu);
 610 extern void perf_counter_update_userpage(struct perf_counter *counter);
 611
 612 extern int perf_counter_overflow(struct perf_counter *counter,
 613                                  int nmi, struct pt_regs *regs, u64 addr);
 614 /*
 615  * Return 1 for a software counter, 0 for a hardware counter
 616  */
 617 static inline int is_software_counter(struct perf_counter *counter)
 618 {
 619         return !perf_event_raw(&counter->attr) &&
 620                 perf_event_type(&counter->attr) != PERF_TYPE_HARDWARE;
 621 }
 622
 623 extern void perf_swcounter_event(u32, u64, int, struct pt_regs *, u64);
 624
 625 extern void __perf_counter_mmap(struct vm_area_struct *vma);
 626
 627 static inline void perf_counter_mmap(struct vm_area_struct *vma)
 628 {
 629         if (vma->vm_flags & VM_EXEC)
 630                 __perf_counter_mmap(vma);
 631 }
 632
 633 extern void perf_counter_comm(struct task_struct *tsk);
 634 extern void perf_counter_fork(struct task_struct *tsk);
 635
 636 extern void perf_counter_task_migration(struct task_struct *task, int cpu);
 637
 638 #define MAX_STACK_DEPTH         255
 639
 640 struct perf_callchain_entry {
 641         u16     nr, hv, kernel, user;
 642         u64     ip[MAX_STACK_DEPTH];
 643 };
 644
 645 extern struct perf_callchain_entry *perf_callchain(struct pt_regs *regs);
 646
 647 extern int sysctl_perf_counter_priv;
 648 extern int sysctl_perf_counter_mlock;
 649 extern int sysctl_perf_counter_limit;
 650
 651 extern void perf_counter_init(void);
 652
 653 #ifndef perf_misc_flags
 654 #define perf_misc_flags(regs)   (user_mode(regs) ? PERF_EVENT_MISC_USER : \
 655                                  PERF_EVENT_MISC_KERNEL)
 656 #define perf_instruction_pointer(regs)  instruction_pointer(regs)
 657 #endif
 658
 659 #else
 660 static inline void
 661 perf_counter_task_sched_in(struct task_struct *task, int cpu)           { }
 662 static inline void
 663 perf_counter_task_sched_out(struct task_struct *task,
 664                             struct task_struct *next, int cpu)          { }
 665 static inline void
 666 perf_counter_task_tick(struct task_struct *task, int cpu)               { }
 667 static inline int perf_counter_init_task(struct task_struct *child)     { return 0; }
 668 static inline void perf_counter_exit_task(struct task_struct *child)    { }
 669 static inline void perf_counter_free_task(struct task_struct *task)     { }
 670 static inline void perf_counter_do_pending(void)                        { }
 671 static inline void perf_counter_print_debug(void)                       { }
 672 static inline void perf_disable(void)                                   { }
 673 static inline void perf_enable(void)                                    { }
 674 static inline int perf_counter_task_disable(void)       { return -EINVAL; }
 675 static inline int perf_counter_task_enable(void)        { return -EINVAL; }
 676
 677 static inline void
 678 perf_swcounter_event(u32 event, u64 nr, int nmi,
 679                      struct pt_regs *regs, u64 addr)                    { }
 680
 681 static inline void perf_counter_mmap(struct vm_area_struct *vma)        { }
 682 static inline void perf_counter_comm(struct task_struct *tsk)           { }
 683 static inline void perf_counter_fork(struct task_struct *tsk)           { }
 684 static inline void perf_counter_init(void)                              { }
 685 static inline void perf_counter_task_migration(struct task_struct *task,
 686                                                int cpu)                 { }
 687 #endif
 688
 689 #endif /* __KERNEL__ */
 690 #endif /* _LINUX_PERF_COUNTER_H */