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  */
  43 static inline int
  44 futex_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  */
  53 static inline int
  54 futex_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  */
  62 static inline int
  63 futex_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  */
  71 static inline int
  72 futex_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 */
  82 static inline int
  83 futex_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 */