tools/perf/bench/futex.h

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