--- /dev/null
+/******************************************************************************
+ *
+ * Copyright © International Business Machines Corp., 2009
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * DESCRIPTION
+ * Glibc independent futex library for testing kernel functionality.
+ *
+ * AUTHOR
+ * Darren Hart <dvhart@linux.intel.com>
+ *
+ * HISTORY
+ * 2009-Nov-6: Initial version by Darren Hart <dvhart@linux.intel.com>
+ *
+ *****************************************************************************/
+
+#ifndef _FUTEXTEST_H
+#define _FUTEXTEST_H
+
+#include <unistd.h>
+#include <sys/syscall.h>
+#include <sys/types.h>
+#include <linux/futex.h>
+
+typedef volatile u_int32_t futex_t;
+#define FUTEX_INITIALIZER 0
+
+/* Define the newer op codes if the system header file is not up to date. */
+#ifndef FUTEX_WAIT_BITSET
+#define FUTEX_WAIT_BITSET 9
+#endif
+#ifndef FUTEX_WAKE_BITSET
+#define FUTEX_WAKE_BITSET 10
+#endif
+#ifndef FUTEX_WAIT_REQUEUE_PI
+#define FUTEX_WAIT_REQUEUE_PI 11
+#endif
+#ifndef FUTEX_CMP_REQUEUE_PI
+#define FUTEX_CMP_REQUEUE_PI 12
+#endif
+#ifndef FUTEX_WAIT_REQUEUE_PI_PRIVATE
+#define FUTEX_WAIT_REQUEUE_PI_PRIVATE (FUTEX_WAIT_REQUEUE_PI | \
+ FUTEX_PRIVATE_FLAG)
+#endif
+#ifndef FUTEX_REQUEUE_PI_PRIVATE
+#define FUTEX_CMP_REQUEUE_PI_PRIVATE (FUTEX_CMP_REQUEUE_PI | \
+ FUTEX_PRIVATE_FLAG)
+#endif
+
+/**
+ * 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(futex_t *uaddr, futex_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(futex_t *uaddr, int nr_wake, int opflags)
+{
+ return futex(uaddr, FUTEX_WAKE, nr_wake, NULL, NULL, 0, opflags);
+}
+
+/**
+ * futex_wait_bitset() - block on uaddr with bitset
+ * @bitset: bitset to be used with futex_wake_bitset
+ */
+static inline int
+futex_wait_bitset(futex_t *uaddr, futex_t val, struct timespec *timeout,
+ u_int32_t bitset, int opflags)
+{
+ return futex(uaddr, FUTEX_WAIT_BITSET, val, timeout, NULL, bitset,
+ opflags);
+}
+
+/**
+ * futex_wake_bitset() - wake one or more tasks blocked on uaddr with bitset
+ * @bitset: bitset to compare with that used in futex_wait_bitset
+ */
+static inline int
+futex_wake_bitset(futex_t *uaddr, int nr_wake, u_int32_t bitset, int opflags)
+{
+ return futex(uaddr, FUTEX_WAKE_BITSET, nr_wake, NULL, NULL, bitset,
+ opflags);
+}
+
+/**
+ * futex_lock_pi() - block on uaddr as a PI mutex
+ * @detect: whether (1) or not (0) to perform deadlock detection
+ */
+static inline int
+futex_lock_pi(futex_t *uaddr, struct timespec *timeout, int detect,
+ int opflags)
+{
+ return futex(uaddr, FUTEX_LOCK_PI, detect, timeout, NULL, 0, opflags);
+}
+
+/**
+ * futex_unlock_pi() - release uaddr as a PI mutex, waking the top waiter
+ */
+static inline int
+futex_unlock_pi(futex_t *uaddr, int opflags)
+{
+ return futex(uaddr, FUTEX_UNLOCK_PI, 0, NULL, NULL, 0, opflags);
+}
+
+/**
+ * futex_wake_op() - FIXME: COME UP WITH A GOOD ONE LINE DESCRIPTION
+ */
+static inline int
+futex_wake_op(futex_t *uaddr, futex_t *uaddr2, int nr_wake, int nr_wake2,
+ int wake_op, int opflags)
+{
+ return futex(uaddr, FUTEX_WAKE_OP, nr_wake, nr_wake2, uaddr2, wake_op,
+ opflags);
+}
+
+/**
+ * futex_requeue() - requeue without expected value comparison, deprecated
+ * @nr_wake: wake up to this many tasks
+ * @nr_requeue: requeue up to this many tasks
+ *
+ * Due to its inherently racy implementation, futex_requeue() is deprecated in
+ * favor of futex_cmp_requeue().
+ */
+static inline int
+futex_requeue(futex_t *uaddr, futex_t *uaddr2, int nr_wake, int nr_requeue,
+ int opflags)
+{
+ return futex(uaddr, FUTEX_REQUEUE, nr_wake, nr_requeue, uaddr2, 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(futex_t *uaddr, futex_t val, futex_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(futex_t *uaddr, futex_t val, futex_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 (PI aware)
+ * @uaddr: non-PI futex source
+ * @uaddr2: PI futex target
+ * @nr_wake: wake up to this many tasks
+ * @nr_requeue: requeue up to this many tasks
+ */
+static inline int
+futex_cmp_requeue_pi(futex_t *uaddr, futex_t val, futex_t *uaddr2, int nr_wake,
+ int nr_requeue, int opflags)
+{
+ return futex(uaddr, FUTEX_CMP_REQUEUE_PI, nr_wake, nr_requeue, uaddr2,
+ val, opflags);
+}
+
+/**
+ * futex_cmpxchg() - atomic compare and exchange
+ * @uaddr: The address of the futex to be modified
+ * @oldval: The expected value of the futex
+ * @newval: The new value to try and assign the futex
+ *
+ * Implement cmpxchg using gcc atomic builtins.
+ * http://gcc.gnu.org/onlinedocs/gcc-4.1.0/gcc/Atomic-Builtins.html
+ *
+ * Return the old futex value.
+ */
+static inline u_int32_t
+futex_cmpxchg(futex_t *uaddr, u_int32_t oldval, u_int32_t newval)
+{
+ return __sync_val_compare_and_swap(uaddr, oldval, newval);
+}
+
+/**
+ * futex_dec() - atomic decrement of the futex value
+ * @uaddr: The address of the futex to be modified
+ *
+ * Return the new futex value.
+ */
+static inline u_int32_t
+futex_dec(futex_t *uaddr)
+{
+ return __sync_sub_and_fetch(uaddr, 1);
+}
+
+/**
+ * futex_inc() - atomic increment of the futex value
+ * @uaddr: the address of the futex to be modified
+ *
+ * Return the new futex value.
+ */
+static inline u_int32_t
+futex_inc(futex_t *uaddr)
+{
+ return __sync_add_and_fetch(uaddr, 1);
+}
+
+/**
+ * futex_set() - atomic decrement of the futex value
+ * @uaddr: the address of the futex to be modified
+ * @newval: New value for the atomic_t
+ *
+ * Return the new futex value.
+ */
+static inline u_int32_t
+futex_set(futex_t *uaddr, u_int32_t newval)
+{
+ *uaddr = newval;
+ return newval;
+}
+
+#endif
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