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262 lines
7.3 KiB
262 lines
7.3 KiB
/* SPDX-License-Identifier: GPL-2.0-or-later */ |
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/****************************************************************************** |
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* |
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* Copyright © International Business Machines Corp., 2009 |
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* |
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* DESCRIPTION |
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* Glibc independent futex library for testing kernel functionality. |
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* |
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* AUTHOR |
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* Darren Hart <[email protected]> |
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* |
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* HISTORY |
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* 2009-Nov-6: Initial version by Darren Hart <[email protected]> |
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* |
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*****************************************************************************/ |
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#ifndef _FUTEXTEST_H |
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#define _FUTEXTEST_H |
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#include <unistd.h> |
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#include <sys/syscall.h> |
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#include <sys/types.h> |
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#include <linux/futex.h> |
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typedef volatile u_int32_t futex_t; |
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#define FUTEX_INITIALIZER 0 |
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/* Define the newer op codes if the system header file is not up to date. */ |
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#ifndef FUTEX_WAIT_BITSET |
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#define FUTEX_WAIT_BITSET 9 |
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#endif |
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#ifndef FUTEX_WAKE_BITSET |
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#define FUTEX_WAKE_BITSET 10 |
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#endif |
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#ifndef FUTEX_WAIT_REQUEUE_PI |
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#define FUTEX_WAIT_REQUEUE_PI 11 |
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#endif |
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#ifndef FUTEX_CMP_REQUEUE_PI |
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#define FUTEX_CMP_REQUEUE_PI 12 |
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#endif |
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#ifndef FUTEX_WAIT_REQUEUE_PI_PRIVATE |
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#define FUTEX_WAIT_REQUEUE_PI_PRIVATE (FUTEX_WAIT_REQUEUE_PI | \ |
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FUTEX_PRIVATE_FLAG) |
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#endif |
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#ifndef FUTEX_REQUEUE_PI_PRIVATE |
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#define FUTEX_CMP_REQUEUE_PI_PRIVATE (FUTEX_CMP_REQUEUE_PI | \ |
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FUTEX_PRIVATE_FLAG) |
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#endif |
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/** |
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* futex() - SYS_futex syscall wrapper |
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* @uaddr: address of first futex |
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* @op: futex op code |
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* @val: typically expected value of uaddr, but varies by op |
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* @timeout: typically an absolute struct timespec (except where noted |
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* otherwise). Overloaded by some ops |
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* @uaddr2: address of second futex for some ops\ |
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* @val3: varies by op |
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* @opflags: flags to be bitwise OR'd with op, such as FUTEX_PRIVATE_FLAG |
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* |
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* futex() is used by all the following futex op wrappers. It can also be |
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* used for misuse and abuse testing. Generally, the specific op wrappers |
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* should be used instead. It is a macro instead of an static inline function as |
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* some of the types over overloaded (timeout is used for nr_requeue for |
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* example). |
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* |
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* These argument descriptions are the defaults for all |
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* like-named arguments in the following wrappers except where noted below. |
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*/ |
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#define futex(uaddr, op, val, timeout, uaddr2, val3, opflags) \ |
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syscall(SYS_futex, uaddr, op | opflags, val, timeout, uaddr2, val3) |
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/** |
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* futex_wait() - block on uaddr with optional timeout |
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* @timeout: relative timeout |
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*/ |
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static inline int |
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futex_wait(futex_t *uaddr, futex_t val, struct timespec *timeout, int opflags) |
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{ |
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return futex(uaddr, FUTEX_WAIT, val, timeout, NULL, 0, opflags); |
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} |
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/** |
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* futex_wake() - wake one or more tasks blocked on uaddr |
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* @nr_wake: wake up to this many tasks |
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*/ |
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static inline int |
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futex_wake(futex_t *uaddr, int nr_wake, int opflags) |
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{ |
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return futex(uaddr, FUTEX_WAKE, nr_wake, NULL, NULL, 0, opflags); |
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} |
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/** |
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* futex_wait_bitset() - block on uaddr with bitset |
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* @bitset: bitset to be used with futex_wake_bitset |
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*/ |
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static inline int |
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futex_wait_bitset(futex_t *uaddr, futex_t val, struct timespec *timeout, |
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u_int32_t bitset, int opflags) |
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{ |
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return futex(uaddr, FUTEX_WAIT_BITSET, val, timeout, NULL, bitset, |
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opflags); |
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} |
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/** |
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* futex_wake_bitset() - wake one or more tasks blocked on uaddr with bitset |
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* @bitset: bitset to compare with that used in futex_wait_bitset |
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*/ |
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static inline int |
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futex_wake_bitset(futex_t *uaddr, int nr_wake, u_int32_t bitset, int opflags) |
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{ |
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return futex(uaddr, FUTEX_WAKE_BITSET, nr_wake, NULL, NULL, bitset, |
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opflags); |
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} |
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/** |
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* futex_lock_pi() - block on uaddr as a PI mutex |
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* @detect: whether (1) or not (0) to perform deadlock detection |
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*/ |
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static inline int |
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futex_lock_pi(futex_t *uaddr, struct timespec *timeout, int detect, |
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int opflags) |
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{ |
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return futex(uaddr, FUTEX_LOCK_PI, detect, timeout, NULL, 0, opflags); |
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} |
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/** |
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* futex_unlock_pi() - release uaddr as a PI mutex, waking the top waiter |
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*/ |
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static inline int |
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futex_unlock_pi(futex_t *uaddr, int opflags) |
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{ |
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return futex(uaddr, FUTEX_UNLOCK_PI, 0, NULL, NULL, 0, opflags); |
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} |
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/** |
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* futex_wake_op() - FIXME: COME UP WITH A GOOD ONE LINE DESCRIPTION |
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*/ |
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static inline int |
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futex_wake_op(futex_t *uaddr, futex_t *uaddr2, int nr_wake, int nr_wake2, |
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int wake_op, int opflags) |
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{ |
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return futex(uaddr, FUTEX_WAKE_OP, nr_wake, nr_wake2, uaddr2, wake_op, |
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opflags); |
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} |
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/** |
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* futex_requeue() - requeue without expected value comparison, deprecated |
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* @nr_wake: wake up to this many tasks |
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* @nr_requeue: requeue up to this many tasks |
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* |
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* Due to its inherently racy implementation, futex_requeue() is deprecated in |
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* favor of futex_cmp_requeue(). |
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*/ |
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static inline int |
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futex_requeue(futex_t *uaddr, futex_t *uaddr2, int nr_wake, int nr_requeue, |
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int opflags) |
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{ |
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return futex(uaddr, FUTEX_REQUEUE, nr_wake, nr_requeue, uaddr2, 0, |
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opflags); |
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} |
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/** |
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* futex_cmp_requeue() - requeue tasks from uaddr to uaddr2 |
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* @nr_wake: wake up to this many tasks |
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* @nr_requeue: requeue up to this many tasks |
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*/ |
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static inline int |
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futex_cmp_requeue(futex_t *uaddr, futex_t val, futex_t *uaddr2, int nr_wake, |
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int nr_requeue, int opflags) |
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{ |
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return futex(uaddr, FUTEX_CMP_REQUEUE, nr_wake, nr_requeue, uaddr2, |
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val, opflags); |
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} |
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/** |
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* futex_wait_requeue_pi() - block on uaddr and prepare to requeue to uaddr2 |
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* @uaddr: non-PI futex source |
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* @uaddr2: PI futex target |
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* |
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* This is the first half of the requeue_pi mechanism. It shall always be |
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* paired with futex_cmp_requeue_pi(). |
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*/ |
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static inline int |
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futex_wait_requeue_pi(futex_t *uaddr, futex_t val, futex_t *uaddr2, |
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struct timespec *timeout, int opflags) |
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{ |
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return futex(uaddr, FUTEX_WAIT_REQUEUE_PI, val, timeout, uaddr2, 0, |
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opflags); |
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} |
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/** |
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* futex_cmp_requeue_pi() - requeue tasks from uaddr to uaddr2 (PI aware) |
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* @uaddr: non-PI futex source |
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* @uaddr2: PI futex target |
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* @nr_wake: wake up to this many tasks |
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* @nr_requeue: requeue up to this many tasks |
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*/ |
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static inline int |
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futex_cmp_requeue_pi(futex_t *uaddr, futex_t val, futex_t *uaddr2, int nr_wake, |
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int nr_requeue, int opflags) |
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{ |
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return futex(uaddr, FUTEX_CMP_REQUEUE_PI, nr_wake, nr_requeue, uaddr2, |
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val, opflags); |
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} |
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/** |
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* futex_cmpxchg() - atomic compare and exchange |
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* @uaddr: The address of the futex to be modified |
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* @oldval: The expected value of the futex |
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* @newval: The new value to try and assign the futex |
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* |
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* Implement cmpxchg using gcc atomic builtins. |
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* http://gcc.gnu.org/onlinedocs/gcc-4.1.0/gcc/Atomic-Builtins.html |
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* |
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* Return the old futex value. |
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*/ |
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static inline u_int32_t |
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futex_cmpxchg(futex_t *uaddr, u_int32_t oldval, u_int32_t newval) |
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{ |
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return __sync_val_compare_and_swap(uaddr, oldval, newval); |
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} |
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/** |
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* futex_dec() - atomic decrement of the futex value |
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* @uaddr: The address of the futex to be modified |
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* |
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* Return the new futex value. |
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*/ |
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static inline u_int32_t |
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futex_dec(futex_t *uaddr) |
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{ |
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return __sync_sub_and_fetch(uaddr, 1); |
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} |
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/** |
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* futex_inc() - atomic increment of the futex value |
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* @uaddr: the address of the futex to be modified |
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* |
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* Return the new futex value. |
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*/ |
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static inline u_int32_t |
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futex_inc(futex_t *uaddr) |
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{ |
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return __sync_add_and_fetch(uaddr, 1); |
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} |
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/** |
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* futex_set() - atomic decrement of the futex value |
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* @uaddr: the address of the futex to be modified |
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* @newval: New value for the atomic_t |
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* |
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* Return the new futex value. |
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*/ |
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static inline u_int32_t |
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futex_set(futex_t *uaddr, u_int32_t newval) |
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{ |
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*uaddr = newval; |
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return newval; |
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} |
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#endif
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