/* SPDX-License-Identifier: GPL-2.0 */
/*
* 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>
struct bench_futex_parameters {
bool silent;
bool fshared;
bool mlockall;
bool multi; /* lock-pi */
bool pi; /* requeue-pi */
bool broadcast; /* requeue */
unsigned int runtime; /* seconds*/
unsigned int nthreads;
unsigned int nfutexes;
unsigned int nwakes;
unsigned int nrequeue;
};
/**
* 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_lock_pi() - block on uaddr as a PI mutex
*/
static inline int
futex_lock_pi(u_int32_t *uaddr, struct timespec *timeout, int opflags)
{
return futex(uaddr, FUTEX_LOCK_PI, 0, timeout, NULL, 0, opflags);
}
/**
* futex_unlock_pi() - release uaddr as a PI mutex, waking the top waiter
*/
static inline int
futex_unlock_pi(u_int32_t *uaddr, int opflags)
{
return futex(uaddr, FUTEX_UNLOCK_PI, 0, 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);
}
/**
* futex_wait_requeue_pi() - block on uaddr and prepare to requeue to uaddr2
* @uaddr: non-PI futex source
* @uaddr2: PI futex target
*
* This is the first half of the requeue_pi mechanism. It shall always be
* paired with futex_cmp_requeue_pi().
*/
static inline int
futex_wait_requeue_pi(u_int32_t *uaddr, u_int32_t val, u_int32_t *uaddr2,
struct timespec *timeout, int opflags)
{
return futex(uaddr, FUTEX_WAIT_REQUEUE_PI, val, timeout, uaddr2, 0,
opflags);
}
/**
* futex_cmp_requeue_pi() - requeue tasks from uaddr to uaddr2
* @uaddr: non-PI futex source
* @uaddr2: PI futex target
* @nr_requeue: requeue up to this many tasks
*
* This is the second half of the requeue_pi mechanism. It shall always be
* paired with futex_wait_requeue_pi(). The first waker is always awoken.
*/
static inline int
futex_cmp_requeue_pi(u_int32_t *uaddr, u_int32_t val, u_int32_t *uaddr2,
int nr_requeue, int opflags)
{
return futex(uaddr, FUTEX_CMP_REQUEUE_PI, 1, nr_requeue, uaddr2,
val, opflags);
}
#endif /* _FUTEX_H */
