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/*
* Glibc independent futex library for testing kernel functionality.
* Shamelessly stolen from Darren Hart <dvhltc@us.ibm.com>
* http://git.kernel.org/cgit/linux/kernel/git/dvhart/futextest.git/
*/
#ifndef _FUTEX_H
#define _FUTEX_H
#include <unistd.h>
#include <sys/syscall.h>
#include <sys/types.h>
#include <linux/futex.h>
/**
* futex() - SYS_futex syscall wrapper
* @uaddr: address of first futex
* @op: futex op code
* @val: typically expected value of uaddr, but varies by op
* @timeout: typically an absolute struct timespec (except where noted
* otherwise). Overloaded by some ops
* @uaddr2: address of second futex for some ops\
* @val3: varies by op
* @opflags: flags to be bitwise OR'd with op, such as FUTEX_PRIVATE_FLAG
*
* futex() is used by all the following futex op wrappers. It can also be
* used for misuse and abuse testing. Generally, the specific op wrappers
* should be used instead. It is a macro instead of an static inline function as
* some of the types over overloaded (timeout is used for nr_requeue for
* example).
*
* These argument descriptions are the defaults for all
* like-named arguments in the following wrappers except where noted below.
*/
#define futex(uaddr, op, val, timeout, uaddr2, val3, opflags) \
syscall(SYS_futex, uaddr, op | opflags, val, timeout, uaddr2, val3)
/**
* futex_wait() - block on uaddr with optional timeout
* @timeout: relative timeout
*/
static inline int
futex_wait(u_int32_t *uaddr, u_int32_t val, struct timespec *timeout, int opflags)
{
return futex(uaddr, FUTEX_WAIT, val, timeout, NULL, 0, opflags);
}
/**
* futex_wake() - wake one or more tasks blocked on uaddr
* @nr_wake: wake up to this many tasks
*/
static inline int
futex_wake(u_int32_t *uaddr, int nr_wake, int opflags)
{
return futex(uaddr, FUTEX_WAKE, nr_wake, NULL, NULL, 0, opflags);
}
/**
* futex_cmp_requeue() - requeue tasks from uaddr to uaddr2
* @nr_wake: wake up to this many tasks
* @nr_requeue: requeue up to this many tasks
*/
static inline int
futex_cmp_requeue(u_int32_t *uaddr, u_int32_t val, u_int32_t *uaddr2, int nr_wake,
int nr_requeue, int opflags)
{
return futex(uaddr, FUTEX_CMP_REQUEUE, nr_wake, nr_requeue, uaddr2,
val, opflags);
}
#endif /* _FUTEX_H */
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