LXR linux/tools/perf/bench/futex.h

   1/* SPDX-License-Identifier: GPL-2.0 */
   2/*
   3 * Glibc independent futex library for testing kernel functionality.
   4 * Shamelessly stolen from Darren Hart <dvhltc@us.ibm.com>
   5 *    http://git.kernel.org/cgit/linux/kernel/git/dvhart/futextest.git/
   6 */
   7
   8#ifndef _FUTEX_H
   9#define _FUTEX_H
  10
  11#include <unistd.h>
  12#include <sys/syscall.h>
  13#include <sys/types.h>
  14#include <linux/futex.h>
  15
  16/**
  17 * futex() - SYS_futex syscall wrapper
  18 * @uaddr:      address of first futex
  19 * @op:         futex op code
  20 * @val:        typically expected value of uaddr, but varies by op
  21 * @timeout:    typically an absolute struct timespec (except where noted
  22 *              otherwise). Overloaded by some ops
  23 * @uaddr2:     address of second futex for some ops\
  24 * @val3:       varies by op
  25 * @opflags:    flags to be bitwise OR'd with op, such as FUTEX_PRIVATE_FLAG
  26 *
  27 * futex() is used by all the following futex op wrappers. It can also be
  28 * used for misuse and abuse testing. Generally, the specific op wrappers
  29 * should be used instead. It is a macro instead of an static inline function as
  30 * some of the types over overloaded (timeout is used for nr_requeue for
  31 * example).
  32 *
  33 * These argument descriptions are the defaults for all
  34 * like-named arguments in the following wrappers except where noted below.
  35 */
  36#define futex(uaddr, op, val, timeout, uaddr2, val3, opflags) \
  37        syscall(SYS_futex, uaddr, op | opflags, val, timeout, uaddr2, val3)
  38
  39/**
  40 * futex_wait() - block on uaddr with optional timeout
  41 * @timeout:    relative timeout
  42 */
  43static inline int
  44futex_wait(u_int32_t *uaddr, u_int32_t val, struct timespec *timeout, int opflags)
  45{
  46        return futex(uaddr, FUTEX_WAIT, val, timeout, NULL, 0, opflags);
  47}
  48
  49/**
  50 * futex_wake() - wake one or more tasks blocked on uaddr
  51 * @nr_wake:    wake up to this many tasks
  52 */
  53static inline int
  54futex_wake(u_int32_t *uaddr, int nr_wake, int opflags)
  55{
  56        return futex(uaddr, FUTEX_WAKE, nr_wake, NULL, NULL, 0, opflags);
  57}
  58
  59/**
  60 * futex_lock_pi() - block on uaddr as a PI mutex
  61 */
  62static inline int
  63futex_lock_pi(u_int32_t *uaddr, struct timespec *timeout, int opflags)
  64{
  65        return futex(uaddr, FUTEX_LOCK_PI, 0, timeout, NULL, 0, opflags);
  66}
  67
  68/**
  69 * futex_unlock_pi() - release uaddr as a PI mutex, waking the top waiter
  70 */
  71static inline int
  72futex_unlock_pi(u_int32_t *uaddr, int opflags)
  73{
  74        return futex(uaddr, FUTEX_UNLOCK_PI, 0, NULL, NULL, 0, opflags);
  75}
  76
  77/**
  78* futex_cmp_requeue() - requeue tasks from uaddr to uaddr2
  79* @nr_wake:        wake up to this many tasks
  80* @nr_requeue:        requeue up to this many tasks
  81*/
  82static inline int
  83futex_cmp_requeue(u_int32_t *uaddr, u_int32_t val, u_int32_t *uaddr2, int nr_wake,
  84                 int nr_requeue, int opflags)
  85{
  86        return futex(uaddr, FUTEX_CMP_REQUEUE, nr_wake, nr_requeue, uaddr2,
  87                 val, opflags);
  88}
  89#endif /* _FUTEX_H */
  90