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 /*
- * Copyright (c) 2003-2005 Apple Computer, Inc. All rights reserved.
+ * Copyright (c) 2003-2019 Apple Inc. All rights reserved.
  *
- * @APPLE_LICENSE_HEADER_START@
+ * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
  *
- * The contents of this file constitute Original Code as defined in and
- * are subject to the Apple Public Source License Version 1.1 (the
- * "License").  You may not use this file except in compliance with the
- * License.  Please obtain a copy of the License at
- * http://www.apple.com/publicsource and read it before using this file.
+ * This file contains Original Code and/or Modifications of Original Code
+ * as defined in and that are subject to the Apple Public Source License
+ * Version 2.0 (the 'License'). You may not use this file except in
+ * compliance with the License. The rights granted to you under the License
+ * may not be used to create, or enable the creation or redistribution of,
+ * unlawful or unlicensed copies of an Apple operating system, or to
+ * circumvent, violate, or enable the circumvention or violation of, any
+ * terms of an Apple operating system software license agreement.
  *
- * This Original Code and all software distributed under the License are
- * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
+ * Please obtain a copy of the License at
+ * http://www.opensource.apple.com/apsl/ and read it before using this file.
+ *
+ * The Original Code and all software distributed under the License are
+ * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
- * License for the specific language governing rights and limitations
- * under the License.
+ * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
+ * Please see the License for the specific language governing rights and
+ * limitations under the License.
  *
- * @APPLE_LICENSE_HEADER_END@
+ * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
  */
 
 #ifndef _KERN_LOCKS_H_
 #define _KERN_LOCKS_H_
 
-#include       <sys/cdefs.h>
-#include       <sys/appleapiopts.h>
-#include       <mach/boolean.h>
-#include       <mach/mach_types.h>
-#include       <kern/kern_types.h>
-#include       <machine/locks.h>
+#include <sys/cdefs.h>
+#include <sys/appleapiopts.h>
+#include <mach/boolean.h>
+#include <mach/mach_types.h>
+#include <kern/kern_types.h>
+#include <kern/lock_group.h>
+#include <machine/locks.h>
 
-#ifdef MACH_KERNEL_PRIVATE
-#include       <kern/queue.h>
+__BEGIN_DECLS
 
-extern void                            lck_mod_init(
-                                                               void);
+typedef unsigned int            lck_sleep_action_t;
 
-typedef        unsigned int    lck_type_t;
+#define LCK_SLEEP_DEFAULT       0x00    /* Release the lock while waiting for the event, then reclaim */
+/* RW locks are returned in the same mode */
+#define LCK_SLEEP_UNLOCK        0x01    /* Release the lock and return unheld */
+#define LCK_SLEEP_SHARED        0x02    /* Reclaim the lock in shared mode (RW only) */
+#define LCK_SLEEP_EXCLUSIVE     0x04    /* Reclaim the lock in exclusive mode (RW only) */
+#define LCK_SLEEP_SPIN          0x08    /* Reclaim the lock in spin mode (mutex only) */
+#define LCK_SLEEP_PROMOTED_PRI  0x10    /* Sleep at a promoted priority */
+#define LCK_SLEEP_SPIN_ALWAYS   0x20    /* Reclaim the lock in spin-always mode (mutex only) */
 
-#define        LCK_TYPE_SPIN   1
-#define        LCK_TYPE_MTX    2
-#define        LCK_TYPE_RW             3
+#define LCK_SLEEP_MASK          0x3f    /* Valid actions */
 
-#endif
+typedef unsigned int            lck_wake_action_t;
 
-typedef        unsigned int            lck_sleep_action_t;
+#define LCK_WAKE_DEFAULT                0x00 /* If waiters are present, transfer their push to the wokenup thread */
+#define LCK_WAKE_DO_NOT_TRANSFER_PUSH   0x01 /* Do not transfer waiters push when waking up */
 
-#define        LCK_SLEEP_DEFAULT       0x00    /* Release the lock while waiting for the event, then reclaim */
-                                                                       /* RW locks are returned in the same mode */
-#define        LCK_SLEEP_UNLOCK        0x01    /* Release the lock and return unheld */
-#define        LCK_SLEEP_SHARED        0x02    /* Reclaim the lock in shared mode (RW only) */
-#define        LCK_SLEEP_EXCLUSIVE     0x04    /* Reclaim the lock in exclusive mode (RW only) */
+#ifdef  XNU_KERNEL_PRIVATE
+#include <kern/startup.h>
 
-#define        LCK_SLEEP_MASK          0x07    /* Valid actions */
+typedef struct _lck_attr_ {
+       unsigned int    lck_attr_val;
+} lck_attr_t;
 
-#ifdef MACH_KERNEL_PRIVATE
+extern lck_attr_t      LockDefaultLckAttr;
 
-typedef struct {
-       uint64_t                        lck_grp_spin_util_cnt;
-       uint64_t                        lck_grp_spin_held_cnt;
-       uint64_t                        lck_grp_spin_miss_cnt;
-       uint64_t                        lck_grp_spin_held_max;
-       uint64_t                        lck_grp_spin_held_cum;
-} lck_grp_spin_stat_t;
+#define LCK_ATTR_NONE                   0
+#define LCK_ATTR_DEBUG                  0x00000001
+#define LCK_ATTR_RW_SHARED_PRIORITY     0x00010000
+#else /* !XNU_KERNEL_PRIVATE */
+typedef struct __lck_attr__ lck_attr_t;
+#endif /* !XNU_KERNEL_PRIVATE */
 
-typedef struct {
-       uint64_t                        lck_grp_mtx_util_cnt;
-       uint64_t                        lck_grp_mtx_held_cnt;
-       uint64_t                        lck_grp_mtx_miss_cnt;
-       uint64_t                        lck_grp_mtx_wait_cnt;
-       uint64_t                        lck_grp_mtx_held_max;
-       uint64_t                        lck_grp_mtx_held_cum;
-       uint64_t                        lck_grp_mtx_wait_max;
-       uint64_t                        lck_grp_mtx_wait_cum;
-} lck_grp_mtx_stat_t;
+#define LCK_ATTR_NULL (lck_attr_t *)NULL
+
+extern  lck_attr_t      *lck_attr_alloc_init(void);
+
+extern  void            lck_attr_setdefault(
+       lck_attr_t              *attr);
+
+extern  void            lck_attr_setdebug(
+       lck_attr_t              *attr);
+
+extern  void            lck_attr_cleardebug(
+       lck_attr_t              *attr);
+
+#ifdef  XNU_KERNEL_PRIVATE
+
+#if __x86_64__
+/*
+ * Extended mutexes are only implemented on x86_64
+ */
+#define HAS_EXT_MUTEXES 1
+#endif /* __x86_64__ */
+
+typedef union {
+       uint16_t tcurnext;
+       struct {
+               uint8_t cticket;
+               uint8_t nticket;
+       };
+} lck_ticket_internal;
 
 typedef struct {
-       uint64_t                        lck_grp_rw_util_cnt;
-       uint64_t                        lck_grp_rw_held_cnt;
-       uint64_t                        lck_grp_rw_miss_cnt;
-       uint64_t                        lck_grp_rw_wait_cnt;
-       uint64_t                        lck_grp_rw_held_max;
-       uint64_t                        lck_grp_rw_held_cum;
-       uint64_t                        lck_grp_rw_wait_max;
-       uint64_t                        lck_grp_rw_wait_cum;
-} lck_grp_rw_stat_t;
-
-typedef        struct _lck_grp_stat_ {
-       lck_grp_spin_stat_t     lck_grp_spin_stat;
-       lck_grp_mtx_stat_t      lck_grp_mtx_stat;
-       lck_grp_rw_stat_t       lck_grp_rw_stat;
-} lck_grp_stat_t;
-
-#define        LCK_GRP_MAX_NAME        64
-
-typedef        struct _lck_grp_ {
-       queue_chain_t           lck_grp_link;
-       unsigned int            lck_grp_refcnt;
-       unsigned int            lck_grp_spincnt;
-       unsigned int            lck_grp_mtxcnt;
-       unsigned int            lck_grp_rwcnt;
-       unsigned int            lck_grp_attr;
-       char                            lck_grp_name[LCK_GRP_MAX_NAME];
-       lck_grp_stat_t          lck_grp_stat;
-} lck_grp_t;
-
-#define LCK_GRP_NULL   (lck_grp_t *)0
+       lck_ticket_internal tu;
+       uintptr_t lck_owner;
+} lck_ticket_t;
+
+void lck_ticket_init(lck_ticket_t *tlock, lck_grp_t *grp);
 
+#if LOCK_STATS
+void lck_ticket_lock(lck_ticket_t *tlock, lck_grp_t *grp);
 #else
-typedef struct __lck_grp__ lck_grp_t;
+void lck_ticket_lock(lck_ticket_t *tlock);
+#define lck_ticket_lock(tlock, grp) lck_ticket_lock(tlock)
+#endif /* LOCK_STATS */
+
+void lck_ticket_unlock(lck_ticket_t *tlock);
+void lck_ticket_assert_owned(lck_ticket_t *tlock);
+
+extern  void            lck_attr_rw_shared_priority(
+       lck_attr_t              *attr);
 #endif
 
-#ifdef MACH_KERNEL_PRIVATE
-typedef        struct _lck_grp_attr_ {
-       unsigned int    grp_attr_val;
-} lck_grp_attr_t;
+extern  void            lck_attr_free(
+       lck_attr_t              *attr);
 
-extern lck_grp_attr_t  LockDefaultGroupAttr;
+#define decl_lck_spin_data(class, name)     class lck_spin_t name
 
-#define LCK_GRP_ATTR_STAT      0x1
+extern lck_spin_t      *lck_spin_alloc_init(
+       lck_grp_t               *grp,
+       lck_attr_t              *attr);
 
-#else
-typedef struct __lck_grp_attr__ lck_grp_attr_t;
-#endif
+extern void             lck_spin_init(
+       lck_spin_t              *lck,
+       lck_grp_t               *grp,
+       lck_attr_t              *attr);
 
-#define LCK_GRP_ATTR_NULL      (lck_grp_attr_t *)0
+extern void             lck_spin_lock(
+       lck_spin_t              *lck);
 
-__BEGIN_DECLS
+extern void             lck_spin_lock_grp(
+       lck_spin_t              *lck,
+       lck_grp_t               *grp);
 
-extern lck_grp_attr_t  *lck_grp_attr_alloc_init(
-                                                                       void);
+extern void             lck_spin_unlock(
+       lck_spin_t              *lck);
 
-extern void                    lck_grp_attr_setdefault(
-                                                                       lck_grp_attr_t  *attr);
+extern void             lck_spin_destroy(
+       lck_spin_t              *lck,
+       lck_grp_t               *grp);
 
-extern void                    lck_grp_attr_setstat(
-                                                                       lck_grp_attr_t  *attr);
+extern void             lck_spin_free(
+       lck_spin_t              *lck,
+       lck_grp_t               *grp);
 
-extern void                    lck_grp_attr_free(
-                                                                       lck_grp_attr_t  *attr);
+extern wait_result_t    lck_spin_sleep(
+       lck_spin_t              *lck,
+       lck_sleep_action_t      lck_sleep_action,
+       event_t                 event,
+       wait_interrupt_t        interruptible);
 
-extern lck_grp_t               *lck_grp_alloc_init(
-                                                                       const char*             grp_name,
-                                                                       lck_grp_attr_t  *attr);
+extern wait_result_t    lck_spin_sleep_grp(
+       lck_spin_t              *lck,
+       lck_sleep_action_t      lck_sleep_action,
+       event_t                 event,
+       wait_interrupt_t        interruptible,
+       lck_grp_t               *grp);
 
-__END_DECLS
+extern wait_result_t    lck_spin_sleep_deadline(
+       lck_spin_t              *lck,
+       lck_sleep_action_t      lck_sleep_action,
+       event_t                 event,
+       wait_interrupt_t        interruptible,
+       uint64_t                deadline);
 
-#ifdef MACH_KERNEL_PRIVATE
-extern void                    lck_grp_init(
-                                                                       lck_grp_t               *grp,
-                                                                       const char*             grp_name,
-                                                                       lck_grp_attr_t  *attr);
+#ifdef  KERNEL_PRIVATE
 
-extern void                    lck_grp_reference(
-                                                                       lck_grp_t               *grp);
+extern void             lck_spin_lock_nopreempt(
+       lck_spin_t              *lck);
 
-extern void                    lck_grp_deallocate(
-                                                                       lck_grp_t                *grp);
+extern void             lck_spin_lock_nopreempt_grp(
+       lck_spin_t              *lck, lck_grp_t *grp);
 
-extern void                    lck_grp_lckcnt_incr(
-                                                                       lck_grp_t               *grp,
-                                                                       lck_type_t              lck_type);
+extern void             lck_spin_unlock_nopreempt(
+       lck_spin_t              *lck);
+
+extern boolean_t        lck_spin_try_lock_grp(
+       lck_spin_t              *lck,
+       lck_grp_t               *grp);
+
+extern boolean_t        lck_spin_try_lock(
+       lck_spin_t              *lck);
+
+extern boolean_t        lck_spin_try_lock_nopreempt(
+       lck_spin_t              *lck);
+
+extern boolean_t        lck_spin_try_lock_nopreempt_grp(
+       lck_spin_t              *lck,
+       lck_grp_t               *grp);
+
+/* NOT SAFE: To be used only by kernel debugger to avoid deadlock. */
+extern boolean_t        kdp_lck_spin_is_acquired(
+       lck_spin_t              *lck);
+
+struct _lck_mtx_ext_;
+extern void lck_mtx_init_ext(
+       lck_mtx_t               *lck,
+       struct _lck_mtx_ext_    *lck_ext,
+       lck_grp_t               *grp,
+       lck_attr_t              *attr);
 
-extern void                    lck_grp_lckcnt_decr(
-                                                                       lck_grp_t               *grp,
-                                                                       lck_type_t              lck_type);
 #endif
 
-__BEGIN_DECLS
+#define decl_lck_mtx_data(class, name)     class lck_mtx_t name
 
-extern void                            lck_grp_free(
-                                                                       lck_grp_t               *grp);
+extern lck_mtx_t        *lck_mtx_alloc_init(
+       lck_grp_t               *grp,
+       lck_attr_t              *attr);
 
-__END_DECLS
+extern void             lck_mtx_init(
+       lck_mtx_t               *lck,
+       lck_grp_t               *grp,
+       lck_attr_t              *attr);
+extern void             lck_mtx_lock(
+       lck_mtx_t               *lck);
 
-#ifdef MACH_KERNEL_PRIVATE
-typedef        struct _lck_attr_ {
-       unsigned int    lck_attr_val;
-} lck_attr_t;
+extern void             lck_mtx_unlock(
+       lck_mtx_t               *lck);
 
-extern lck_attr_t      LockDefaultLckAttr;
+extern void             lck_mtx_destroy(
+       lck_mtx_t               *lck,
+       lck_grp_t               *grp);
 
-#define        LCK_ATTR_NONE           0
-#define        LCK_ATTR_DEBUG  0x1
+extern void             lck_mtx_free(
+       lck_mtx_t               *lck,
+       lck_grp_t               *grp);
 
-#else
-typedef struct __lck_attr__ lck_attr_t;
-#endif
+extern wait_result_t    lck_mtx_sleep(
+       lck_mtx_t               *lck,
+       lck_sleep_action_t      lck_sleep_action,
+       event_t                 event,
+       wait_interrupt_t        interruptible);
 
-#define LCK_ATTR_NULL (lck_attr_t *)0
+extern wait_result_t    lck_mtx_sleep_deadline(
+       lck_mtx_t               *lck,
+       lck_sleep_action_t      lck_sleep_action,
+       event_t                 event,
+       wait_interrupt_t        interruptible,
+       uint64_t                deadline);
 
-__BEGIN_DECLS
+#ifdef KERNEL_PRIVATE
+/*
+ * Name: lck_spin_sleep_with_inheritor
+ *
+ * Description: deschedule the current thread and wait on the waitq associated with event to be woken up.
+ *              While waiting, the sched priority of the waiting thread will contribute to the push of the event that will
+ *              be directed to the inheritor specified.
+ *              An interruptible mode and deadline can be specified to return earlier from the wait.
+ *
+ * Args:
+ *   Arg1: lck_spin_t lock used to protect the sleep. The lock will be dropped while sleeping and reaquired before returning according to the sleep action specified.
+ *   Arg2: sleep action. LCK_SLEEP_DEFAULT, LCK_SLEEP_UNLOCK.
+ *   Arg3: event to wait on.
+ *   Arg4: thread to propagate the event push to.
+ *   Arg5: interruptible flag for wait.
+ *   Arg6: deadline for wait.
+ *
+ * Conditions: Lock must be held. Returns with the lock held according to the sleep action specified.
+ *             Lock will be dropped while waiting.
+ *             The inheritor specified cannot run in user space until another inheritor is specified for the event or a
+ *             wakeup for the event is called.
+ *
+ * Returns: result of the wait.
+ */
+extern wait_result_t lck_spin_sleep_with_inheritor(lck_spin_t *lock, lck_sleep_action_t lck_sleep_action, event_t event, thread_t inheritor, wait_interrupt_t interruptible, uint64_t deadline);
+
+/*
+ * Name: lck_mtx_sleep_with_inheritor
+ *
+ * Description: deschedule the current thread and wait on the waitq associated with event to be woken up.
+ *              While waiting, the sched priority of the waiting thread will contribute to the push of the event that will
+ *              be directed to the inheritor specified.
+ *              An interruptible mode and deadline can be specified to return earlier from the wait.
+ *
+ * Args:
+ *   Arg1: lck_mtx_t lock used to protect the sleep. The lock will be dropped while sleeping and reaquired before returning according to the sleep action specified.
+ *   Arg2: sleep action. LCK_SLEEP_DEFAULT, LCK_SLEEP_UNLOCK, LCK_SLEEP_SPIN, LCK_SLEEP_SPIN_ALWAYS.
+ *   Arg3: event to wait on.
+ *   Arg4: thread to propagate the event push to.
+ *   Arg5: interruptible flag for wait.
+ *   Arg6: deadline for wait.
+ *
+ * Conditions: Lock must be held. Returns with the lock held according to the sleep action specified.
+ *             Lock will be dropped while waiting.
+ *             The inheritor specified cannot run in user space until another inheritor is specified for the event or a
+ *             wakeup for the event is called.
+ *
+ * Returns: result of the wait.
+ */
+extern wait_result_t lck_mtx_sleep_with_inheritor(lck_mtx_t *lock, lck_sleep_action_t lck_sleep_action, event_t event, thread_t inheritor, wait_interrupt_t interruptible, uint64_t deadline);
+
+/*
+ * Name: lck_mtx_sleep_with_inheritor
+ *
+ * Description: deschedule the current thread and wait on the waitq associated with event to be woken up.
+ *              While waiting, the sched priority of the waiting thread will contribute to the push of the event that will
+ *              be directed to the inheritor specified.
+ *              An interruptible mode and deadline can be specified to return earlier from the wait.
+ *
+ * Args:
+ *   Arg1: lck_rw_t lock used to protect the sleep. The lock will be dropped while sleeping and reaquired before returning according to the sleep action specified.
+ *   Arg2: sleep action. LCK_SLEEP_DEFAULT, LCK_SLEEP_SHARED, LCK_SLEEP_EXCLUSIVE.
+ *   Arg3: event to wait on.
+ *   Arg4: thread to propagate the event push to.
+ *   Arg5: interruptible flag for wait.
+ *   Arg6: deadline for wait.
+ *
+ * Conditions: Lock must be held. Returns with the lock held according to the sleep action specified.
+ *             Lock will be dropped while waiting.
+ *             The inheritor specified cannot run in user space until another inheritor is specified for the event or a
+ *             wakeup for the event is called.
+ *
+ * Returns: result of the wait.
+ */
+extern wait_result_t lck_rw_sleep_with_inheritor(lck_rw_t *lock, lck_sleep_action_t lck_sleep_action, event_t event, thread_t inheritor, wait_interrupt_t interruptible, uint64_t deadline);
+
+/*
+ * Name: wakeup_one_with_inheritor
+ *
+ * Description: wake up one waiter for event if any. The thread woken up will be the one with the higher sched priority waiting on event.
+ *              The push for the event will be transferred from the last inheritor to the woken up thread.
+ *
+ * Args:
+ *   Arg1: event to wake from.
+ *   Arg2: wait result to pass to the woken up thread.
+ *   Arg3: pointer for storing the thread wokenup.
+ *
+ * Returns: KERN_NOT_WAITING if no threads were waiting, KERN_SUCCESS otherwise.
+ *
+ * Conditions: The new inheritor wokenup cannot run in user space until another inheritor is specified for the event or a
+ *             wakeup for the event is called.
+ *             A reference for the wokenup thread is acquired.
+ *             NOTE: this cannot be called from interrupt context.
+ */
+extern kern_return_t wakeup_one_with_inheritor(event_t event, wait_result_t result, lck_wake_action_t action, thread_t *thread_wokenup);
+
+/*
+ * Name: wakeup_all_with_inheritor
+ *
+ * Description: wake up all waiters waiting for event. The old inheritor will lose the push.
+ *
+ * Args:
+ *   Arg1: event to wake from.
+ *   Arg2: wait result to pass to the woken up threads.
+ *
+ * Returns: KERN_NOT_WAITING if no threads were waiting, KERN_SUCCESS otherwise.
+ *
+ * Conditions: NOTE: this cannot be called from interrupt context.
+ */
+extern kern_return_t wakeup_all_with_inheritor(event_t event, wait_result_t result);
+
+/*
+ * Name: change_sleep_inheritor
+ *
+ * Description: Redirect the push of the waiting threads of event to the new inheritor specified.
+ *
+ * Args:
+ *   Arg1: event to redirect the push.
+ *   Arg2: new inheritor for event.
+ *
+ * Returns: KERN_NOT_WAITING if no threads were waiting, KERN_SUCCESS otherwise.
+ *
+ * Conditions: In case of success, the new inheritor cannot run in user space until another inheritor is specified for the event or a
+ *             wakeup for the event is called.
+ *             NOTE: this cannot be called from interrupt context.
+ */
+extern kern_return_t change_sleep_inheritor(event_t event, thread_t inheritor);
+
+/*
+ * gate structure
+ */
+typedef struct gate {
+       uintptr_t gate_data; // thread holder, interlock bit and waiter bit
+       struct turnstile *turnstile; // protected by the interlock bit
+} gate_t;
+
+#define GATE_ILOCK_BIT   0
+#define GATE_WAITERS_BIT 1
+
+#define GATE_ILOCK (1 << GATE_ILOCK_BIT)
+#define GATE_WAITERS (1 << GATE_WAITERS_BIT)
+
+#define gate_ilock(gate) hw_lock_bit((hw_lock_bit_t*)(&(gate)->gate_data), GATE_ILOCK_BIT, LCK_GRP_NULL)
+#define gate_iunlock(gate) hw_unlock_bit((hw_lock_bit_t*)(&(gate)->gate_data), GATE_ILOCK_BIT)
+#define gate_has_waiters(state) ((state & GATE_WAITERS) != 0)
+#define ordered_load_gate(gate) os_atomic_load(&(gate)->gate_data, compiler_acq_rel)
+#define ordered_store_gate(gate, value)  os_atomic_store(&(gate)->gate_data, value, compiler_acq_rel)
+
+#define GATE_THREAD_MASK (~(uintptr_t)(GATE_ILOCK | GATE_WAITERS))
+#define GATE_STATE_TO_THREAD(state) (thread_t)(state & GATE_THREAD_MASK)
+#define GATE_THREAD_TO_STATE(thread) ((uintptr_t)thread)
+
+/*
+ * Possible gate_wait_result_t values.
+ */
+typedef int gate_wait_result_t;
+#define GATE_HANDOFF       0
+#define GATE_OPENED        1
+#define GATE_TIMED_OUT     2
+#define GATE_INTERRUPTED   3
+
+/*
+ * Gate flags used by gate_assert
+ */
+#define GATE_ASSERT_CLOSED         0
+#define GATE_ASSERT_OPEN           1
+#define GATE_ASSERT_HELD           2
+
+/*
+ * Gate flags used by gate_handoff
+ */
+#define GATE_HANDOFF_DEFAULT                    0
+#define GATE_HANDOFF_OPEN_IF_NO_WAITERS         1
+
+#define GATE_EVENT(gate)     ((event_t) gate)
+#define EVENT_TO_GATE(event) ((gate_t *) event)
+
+/*
+ * Name: decl_lck_rw_gate_data
+ *
+ * Description: declares a gate variable with specified storage class.
+ *              The gate itself will be stored in this variable and it is the caller's responsibility
+ *              to ensure that this variable's memory is going to be accessible by all threads that will use
+ *              the gate.
+ *              Every gate function will require a pointer to this variable as parameter. The same pointer should
+ *              be used in every thread.
+ *
+ *              The variable needs to be initialized once with lck_rw_gate_init() and destroyed once with
+ *              lck_rw_gate_destroy() when not needed anymore.
+ *
+ *              The gate will be used in conjunction with a lck_rw_t.
+ *
+ * Args:
+ *   Arg1: storage class.
+ *   Arg2: variable name.
+ */
+#define decl_lck_rw_gate_data(class, name)                              class gate_t name
+
+/*
+ * Name: lck_rw_gate_init
+ *
+ * Description: initializes a variable declared with decl_lck_rw_gate_data.
+ *
+ * Args:
+ *   Arg1: lck_rw_t lock used to protect the gate.
+ *   Arg2: pointer to the gate data declared with decl_lck_rw_gate_data.
+ */
+extern void lck_rw_gate_init(lck_rw_t *lock, gate_t *gate);
+
+/*
+ * Name: lck_rw_gate_destroy
+ *
+ * Description: destroys a variable previously initialized.
+ *
+ * Args:
+ *   Arg1: lck_rw_t lock used to protect the gate.
+ *   Arg2: pointer to the gate data declared with decl_lck_rw_gate_data.
+ */
+extern void lck_rw_gate_destroy(lck_rw_t *lock, gate_t *gate);
+
+/*
+ * Name: lck_rw_gate_try_close
+ *
+ * Description: Tries to close the gate.
+ *              In case of success the current thread will be set as
+ *              the holder of the gate.
+ *
+ * Args:
+ *   Arg1: lck_rw_t lock used to protect the gate.
+ *   Arg2: pointer to the gate data declared with decl_lck_rw_gate_data.
+ *
+ * Conditions: Lock must be held. Returns with the lock held.
+ *
+ * Returns:
+ *          KERN_SUCCESS in case the gate was successfully closed. The current thread is the new holder
+ *          of the gate.
+ *          A matching lck_rw_gate_open() or lck_rw_gate_handoff() needs to be called later on
+ *          to wake up possible waiters on the gate before returning to userspace.
+ *          If the intent is to conditionally probe the gate before waiting, the lock must not be dropped
+ *          between the calls to lck_rw_gate_try_close() and lck_rw_gate_wait().
+ *
+ *          KERN_FAILURE in case the gate was already closed. Will panic if the current thread was already the holder of the gate.
+ *          lck_rw_gate_wait() should be called instead if the intent is to unconditionally wait on this gate.
+ *          The calls to lck_rw_gate_try_close() and lck_rw_gate_wait() should
+ *          be done without dropping the lock that is protecting the gate in between.
+ */
+extern kern_return_t lck_rw_gate_try_close(lck_rw_t *lock, gate_t *gate);
+
+/*
+ * Name: lck_rw_gate_close
+ *
+ * Description: Closes the gate. The current thread will be set as
+ *              the holder of the gate. Will panic if the gate is already closed.
+ *              A matching lck_rw_gate_open() or lck_rw_gate_handoff() needs to be called later on
+ *              to wake up possible waiters on the gate before returning to userspace.
+ *
+ * Args:
+ *   Arg1: lck_rw_t lock used to protect the gate.
+ *   Arg2: pointer to the gate data declared with decl_lck_rw_gate_data.
+ *
+ * Conditions: Lock must be held. Returns with the lock held.
+ *             The gate must be open.
+ *
+ */
+extern void lck_rw_gate_close(lck_rw_t *lock, gate_t *gate);
 
-extern lck_attr_t              *lck_attr_alloc_init(
-                                                                       void);
 
-extern void                    lck_attr_setdefault(
-                                                                       lck_attr_t              *attr);
+/*
+ * Name: lck_rw_gate_open
+ *
+ * Description: Opens the gate and wakes up possible waiters.
+ *
+ * Args:
+ *   Arg1: lck_rw_t lock used to protect the gate.
+ *   Arg2: pointer to the gate data declared with decl_lck_rw_gate_data.
+ *
+ * Conditions: Lock must be held. Returns with the lock held.
+ *             The current thread must be the holder of the gate.
+ *
+ */
+extern void lck_rw_gate_open(lck_rw_t *lock, gate_t *gate);
+
+/*
+ * Name: lck_rw_gate_handoff
+ *
+ * Description: Tries to transfer the ownership of the gate. The waiter with highest sched
+ *              priority will be selected as the new holder of the gate, and woken up,
+ *              with the gate remaining in the closed state throughout.
+ *              If no waiters are present, the gate will be kept closed and KERN_NOT_WAITING
+ *              will be returned.
+ *              GATE_HANDOFF_OPEN_IF_NO_WAITERS flag can be used to specify if the gate should be opened in
+ *              case no waiters were found.
+ *
+ *
+ * Args:
+ *   Arg1: lck_rw_t lock used to protect the gate.
+ *   Arg2: pointer to the gate data declared with decl_lck_rw_gate_data.
+ *   Arg3: flags - GATE_HANDOFF_DEFAULT or GATE_HANDOFF_OPEN_IF_NO_WAITERS
+ *
+ * Conditions: Lock must be held. Returns with the lock held.
+ *             The current thread must be the holder of the gate.
+ *
+ * Returns:
+ *          KERN_SUCCESS in case one of the waiters became the new holder.
+ *          KERN_NOT_WAITING in case there were no waiters.
+ *
+ */
+extern kern_return_t lck_rw_gate_handoff(lck_rw_t *lock, gate_t *gate, int flags);
+
+/*
+ * Name: lck_rw_gate_steal
+ *
+ * Description: Set the current ownership of the gate. It sets the current thread as the
+ *              new holder of the gate.
+ *              A matching lck_rw_gate_open() or lck_rw_gate_handoff() needs to be called later on
+ *              to wake up possible waiters on the gate before returning to userspace.
+ *              NOTE: the previous holder should not call lck_rw_gate_open() or lck_rw_gate_handoff()
+ *              anymore.
+ *
+ *
+ * Args:
+ *   Arg1: lck_rw_t lock used to protect the gate.
+ *   Arg2: pointer to the gate data declared with decl_lck_rw_gate_data.
+ *
+ * Conditions: Lock must be held. Returns with the lock held.
+ *             The gate must be closed and the current thread must not already be the holder.
+ *
+ */
+extern void lck_rw_gate_steal(lck_rw_t *lock, gate_t *gate);
+
+/*
+ * Name: lck_rw_gate_wait
+ *
+ * Description: Waits for the current thread to become the holder of the gate or for the
+ *              gate to become open. An interruptible mode and deadline can be specified
+ *              to return earlier from the wait.
+ *
+ * Args:
+ *   Arg1: lck_rw_t lock used to protect the gate.
+ *   Arg2: pointer to the gate data declared with decl_lck_rw_gate_data.
+ *   Arg3: sleep action. LCK_SLEEP_DEFAULT, LCK_SLEEP_SHARED, LCK_SLEEP_EXCLUSIVE.
+ *   Arg3: interruptible flag for wait.
+ *   Arg4: deadline
+ *
+ * Conditions: Lock must be held. Returns with the lock held according to the sleep action specified.
+ *             Lock will be dropped while waiting.
+ *             The gate must be closed.
+ *
+ * Returns: Reason why the thread was woken up.
+ *          GATE_HANDOFF - the current thread was handed off the ownership of the gate.
+ *                         A matching lck_rw_gate_open() or lck_rw_gate_handoff() needs to be called later on
+ *                         to wake up possible waiters on the gate before returning to userspace.
+ *          GATE_OPENED - the gate was opened by the holder.
+ *          GATE_TIMED_OUT - the thread was woken up by a timeout.
+ *          GATE_INTERRUPTED - the thread was interrupted while sleeping.
+ *
+ */
+extern gate_wait_result_t lck_rw_gate_wait(lck_rw_t *lock, gate_t *gate, lck_sleep_action_t lck_sleep_action, wait_interrupt_t interruptible, uint64_t deadline);
+
+/*
+ * Name: lck_rw_gate_assert
+ *
+ * Description: asserts that the gate is in the specified state.
+ *
+ * Args:
+ *   Arg1: lck_rw_t lock used to protect the gate.
+ *   Arg2: pointer to the gate data declared with decl_lck_rw_gate_data.
+ *   Arg3: flags to specified assert type.
+ *         GATE_ASSERT_CLOSED - the gate is currently closed
+ *         GATE_ASSERT_OPEN - the gate is currently opened
+ *         GATE_ASSERT_HELD - the gate is currently closed and the current thread is the holder
+ */
+extern void lck_rw_gate_assert(lck_rw_t *lock, gate_t *gate, int flags);
 
-extern void                    lck_attr_setdebug(
-                                                                       lck_attr_t              *attr);
+/*
+ * Name: decl_lck_mtx_gate_data
+ *
+ * Description: declares a gate variable with specified storage class.
+ *              The gate itself will be stored in this variable and it is the caller's responsibility
+ *              to ensure that this variable's memory is going to be accessible by all threads that will use
+ *              the gate.
+ *              Every gate function will require a pointer to this variable as parameter. The same pointer should
+ *              be used in every thread.
+ *
+ *              The variable needs to be initialized once with lck_mtx_gate_init() and destroyed once with
+ *              lck_mtx_gate_destroy() when not needed anymore.
+ *
+ *              The gate will be used in conjunction with a lck_mtx_t.
+ *
+ * Args:
+ *   Arg1: storage class.
+ *   Arg2: variable name.
+ */
+#define decl_lck_mtx_gate_data(class, name)                             class gate_t name
 
-extern void                    lck_attr_free(
-                                                                       lck_attr_t              *attr);
+/*
+ * Name: lck_mtx_gate_init
+ *
+ * Description: initializes a variable declared with decl_lck_mtx_gate_data.
+ *
+ * Args:
+ *   Arg1: lck_mtx_t lock used to protect the gate.
+ *   Arg2: pointer to the gate data declared with decl_lck_mtx_gate_data.
+ */
+extern void lck_mtx_gate_init(lck_mtx_t *lock, gate_t *gate);
 
-#define decl_lck_spin_data(class,name)     class lck_spin_t name;
+/*
+ * Name: lck_mtx_gate_destroy
+ *
+ * Description: destroys a variable previously initialized
+ *
+ * Args:
+ *   Arg1: lck_mtx_t lock used to protect the gate.
+ *   Arg2: pointer to the gate data declared with decl_lck_mtx_gate_data.
+ */
+extern void lck_mtx_gate_destroy(lck_mtx_t *lock, gate_t *gate);
 
-extern lck_spin_t              *lck_spin_alloc_init(
-                                                                       lck_grp_t               *grp,
-                                                                       lck_attr_t              *attr);
+/*
+ * Name: lck_mtx_gate_try_close
+ *
+ * Description: Tries to close the gate.
+ *              In case of success the current thread will be set as
+ *              the holder of the gate.
+ *
+ * Args:
+ *   Arg1: lck_mtx_t lock used to protect the gate.
+ *   Arg2: pointer to the gate data declared with decl_lck_mtx_gate_data.
+ *
+ * Conditions: Lock must be held. Returns with the lock held.
+ *
+ * Returns:
+ *          KERN_SUCCESS in case the gate was successfully closed. The current thread is the new holder
+ *          of the gate.
+ *          A matching lck_mtx_gate_open() or lck_mtx_gate_handoff() needs to be called later on
+ *          to wake up possible waiters on the gate before returning to userspace.
+ *          If the intent is to conditionally probe the gate before waiting, the lock must not be dropped
+ *          between the calls to lck_mtx_gate_try_close() and lck_mtx_gate_wait().
+ *
+ *          KERN_FAILURE in case the gate was already closed. Will panic if the current thread was already the holder of the gate.
+ *          lck_mtx_gate_wait() should be called instead if the intent is to unconditionally wait on this gate.
+ *          The calls to lck_mtx_gate_try_close() and lck_mtx_gate_wait() should
+ *          be done without dropping the lock that is protecting the gate in between.
+ */
+extern kern_return_t lck_mtx_gate_try_close(lck_mtx_t *lock, gate_t *gate);
 
-extern void                            lck_spin_init(
-                                                                       lck_spin_t              *lck, 
-                                                                       lck_grp_t               *grp,
-                                                                       lck_attr_t              *attr);
+/*
+ * Name: lck_mtx_gate_close
+ *
+ * Description: Closes the gate. The current thread will be set as
+ *              the holder of the gate. Will panic if the gate is already closed.
+ *              A matching lck_mtx_gate_open() or lck_mtx_gate_handoff() needs to be called later on
+ *              to wake up possible waiters on the gate before returning to userspace.
+ *
+ * Args:
+ *   Arg1: lck_mtx_t lock used to protect the gate.
+ *   Arg2: pointer to the gate data declared with decl_lck_mtx_gate_data.
+ *
+ * Conditions: Lock must be held. Returns with the lock held.
+ *             The gate must be open.
+ *
+ */
+extern void lck_mtx_gate_close(lck_mtx_t *lock, gate_t *gate);
 
-extern void                            lck_spin_lock(
-                                                                       lck_spin_t              *lck);
+/*
+ * Name: lck_mtx_gate_open
+ *
+ * Description: Opens of the gate and wakes up possible waiters.
+ *
+ * Args:
+ *   Arg1: lck_mtx_t lock used to protect the gate.
+ *   Arg2: pointer to the gate data declared with decl_lck_mtx_gate_data.
+ *
+ * Conditions: Lock must be held. Returns with the lock held.
+ *             The current thread must be the holder of the gate.
+ *
+ */
+extern void lck_mtx_gate_open(lck_mtx_t *lock, gate_t *gate);
 
-extern void                            lck_spin_unlock(
-                                                                       lck_spin_t              *lck);
+/*
+ * Name: lck_mtx_gate_handoff
+ *
+ * Description: Set the current ownership of the gate. The waiter with highest sched
+ *              priority will be selected as the new holder of the gate, and woken up,
+ *              with the gate remaining in the closed state throughout.
+ *              If no waiters are present, the gate will be kept closed and KERN_NOT_WAITING
+ *              will be returned.
+ *              OPEN_ON_FAILURE flag can be used to specify if the gate should be opened in
+ *              case no waiters were found.
+ *
+ *
+ * Args:
+ *   Arg1: lck_mtx_t lock used to protect the gate.
+ *   Arg2: pointer to the gate data declared with decl_lck_mtx_gate_data.
+ *   Arg3: flags - GATE_NO_FALGS or OPEN_ON_FAILURE
+ *
+ * Conditions: Lock must be held. Returns with the lock held.
+ *             The current thread must be the holder of the gate.
+ *
+ * Returns:
+ *          KERN_SUCCESS in case one of the waiters became the new holder.
+ *          KERN_NOT_WAITING in case there were no waiters.
+ *
+ */
+extern kern_return_t lck_mtx_gate_handoff(lck_mtx_t *lock, gate_t *gate, int flags);
 
-extern void                            lck_spin_destroy(
-                                                                       lck_spin_t              *lck,
-                                                                       lck_grp_t               *grp);
+/*
+ * Name: lck_mtx_gate_steal
+ *
+ * Description: Steals the ownership of the gate. It sets the current thread as the
+ *              new holder of the gate.
+ *              A matching lck_mtx_gate_open() or lck_mtx_gate_handoff() needs to be called later on
+ *              to wake up possible waiters on the gate before returning to userspace.
+ *              NOTE: the previous holder should not call lck_mtx_gate_open() or lck_mtx_gate_handoff()
+ *              anymore.
+ *
+ *
+ * Args:
+ *   Arg1: lck_mtx_t lock used to protect the gate.
+ *   Arg2: pointer to the gate data declared with decl_lck_mtx_gate_data.
+ *
+ * Conditions: Lock must be held. Returns with the lock held.
+ *             The gate must be closed and the current thread must not already be the holder.
+ *
+ */
+extern void lck_mtx_gate_steal(lck_mtx_t *lock, gate_t *gate);
 
-extern void                            lck_spin_free(
-                                                                       lck_spin_t              *lck,
-                                                                       lck_grp_t               *grp);
+/*
+ * Name: lck_mtx_gate_wait
+ *
+ * Description: Waits for the current thread to become the holder of the gate or for the
+ *              gate to become open. An interruptible mode and deadline can be specified
+ *              to return earlier from the wait.
+ *
+ * Args:
+ *   Arg1: lck_mtx_t lock used to protect the gate.
+ *   Arg2: pointer to the gate data declared with decl_lck_mtx_gate_data.
+ *   Arg3: sleep action. LCK_SLEEP_DEFAULT, LCK_SLEEP_UNLOCK, LCK_SLEEP_SPIN, LCK_SLEEP_SPIN_ALWAYS.
+ *   Arg3: interruptible flag for wait.
+ *   Arg4: deadline
+ *
+ * Conditions: Lock must be held. Returns with the lock held according to the sleep action specified.
+ *             Lock will be dropped while waiting.
+ *             The gate must be closed.
+ *
+ * Returns: Reason why the thread was woken up.
+ *          GATE_HANDOFF - the current thread was handed off the ownership of the gate.
+ *                         A matching lck_mtx_gate_open() or lck_mtx_gate_handoff() needs to be called later on
+ *                         to wake up possible waiters on the gate before returning to userspace.
+ *          GATE_OPENED - the gate was opened by the holder.
+ *          GATE_TIMED_OUT - the thread was woken up by a timeout.
+ *          GATE_INTERRUPTED - the thread was interrupted while sleeping.
+ *
+ */
+extern gate_wait_result_t lck_mtx_gate_wait(lck_mtx_t *lock, gate_t *gate, lck_sleep_action_t lck_sleep_action, wait_interrupt_t interruptible, uint64_t deadline);
 
-extern wait_result_t   lck_spin_sleep(
-                                                                       lck_spin_t                      *lck,
-                                                                       lck_sleep_action_t      lck_sleep_action,
-                                                                       event_t                         event,
-                                                                       wait_interrupt_t        interruptible);
+/*
+ * Name: lck_mtx_gate_assert
+ *
+ * Description: asserts that the gate is in the specified state.
+ *
+ * Args:
+ *   Arg1: lck_mtx_t lock used to protect the gate.
+ *   Arg2: pointer to the gate data declared with decl_lck_mtx_gate_data.
+ *   Arg3: flags to specified assert type.
+ *         GATE_ASSERT_CLOSED - the gate is currently closed
+ *         GATE_ASSERT_OPEN - the gate is currently opened
+ *         GATE_ASSERT_HELD - the gate is currently closed and the current thread is the holder
+ */
+extern void lck_mtx_gate_assert(lck_mtx_t *lock, gate_t *gate, int flags);
 
-extern wait_result_t   lck_spin_sleep_deadline(
-                                                                       lck_spin_t                      *lck,
-                                                                       lck_sleep_action_t      lck_sleep_action,
-                                                                       event_t                         event,
-                                                                       wait_interrupt_t        interruptible,
-                                                                       uint64_t                        deadline);
 
-#ifdef KERNEL_PRIVATE
+#endif //KERNEL_PRIVATE
 
-extern boolean_t               lck_spin_try_lock(
-                                                                       lck_spin_t              *lck);
+#if DEVELOPMENT || DEBUG
+#define FULL_CONTENDED 0
+#define HALF_CONTENDED 1
+#define MAX_CONDENDED  2
 
+extern void             erase_all_test_mtx_stats(void);
+extern int              get_test_mtx_stats_string(char* buffer, int buffer_size);
+extern void             lck_mtx_test_init(void);
+extern void             lck_mtx_test_lock(void);
+extern void             lck_mtx_test_unlock(void);
+extern int              lck_mtx_test_mtx_uncontended(int iter, char* buffer, int buffer_size);
+extern int              lck_mtx_test_mtx_contended(int iter, char* buffer, int buffer_size, int type);
+extern int              lck_mtx_test_mtx_uncontended_loop_time(int iter, char* buffer, int buffer_size);
+extern int              lck_mtx_test_mtx_contended_loop_time(int iter, char* buffer, int buffer_size, int type);
 #endif
+#ifdef  KERNEL_PRIVATE
 
+extern boolean_t        lck_mtx_try_lock(
+       lck_mtx_t               *lck);
 
-#define decl_lck_mtx_data(class,name)     class lck_mtx_t name;
+extern void             mutex_pause(uint32_t);
 
-extern lck_mtx_t               *lck_mtx_alloc_init(
-                                                                       lck_grp_t               *grp,
-                                                                       lck_attr_t              *attr);
+extern void             lck_mtx_yield(
+       lck_mtx_t               *lck);
 
-extern void                            lck_mtx_init(
-                                                                       lck_mtx_t               *lck, 
-                                                                       lck_grp_t               *grp,
-                                                                       lck_attr_t              *attr);
+extern boolean_t        lck_mtx_try_lock_spin(
+       lck_mtx_t               *lck);
 
-extern void                            lck_mtx_lock(
-                                                                       lck_mtx_t               *lck);
+extern void             lck_mtx_lock_spin(
+       lck_mtx_t               *lck);
 
-extern void                            lck_mtx_unlock(
-                                                                       lck_mtx_t               *lck);
+extern boolean_t        kdp_lck_mtx_lock_spin_is_acquired(
+       lck_mtx_t               *lck);
 
-extern void                            lck_mtx_destroy(
-                                                                       lck_mtx_t               *lck,
-                                                                       lck_grp_t               *grp);
+extern void             lck_mtx_convert_spin(
+       lck_mtx_t               *lck);
 
-extern void                            lck_mtx_free(
-                                                                       lck_mtx_t               *lck,
-                                                                       lck_grp_t               *grp);
+extern void             lck_mtx_lock_spin_always(
+       lck_mtx_t               *lck);
 
-extern wait_result_t   lck_mtx_sleep(
-                                                                       lck_mtx_t                       *lck,
-                                                                       lck_sleep_action_t      lck_sleep_action,
-                                                                       event_t                         event,
-                                                                       wait_interrupt_t        interruptible);
+extern boolean_t        lck_mtx_try_lock_spin_always(
+       lck_mtx_t               *lck);
 
-extern wait_result_t   lck_mtx_sleep_deadline(
-                                                                       lck_mtx_t                       *lck,
-                                                                       lck_sleep_action_t      lck_sleep_action,
-                                                                       event_t                         event,
-                                                                       wait_interrupt_t        interruptible,
-                                                                       uint64_t                        deadline);
+#define lck_mtx_unlock_always(l)        lck_mtx_unlock(l)
 
-#ifdef KERNEL_PRIVATE
+extern void             lck_spin_assert(
+       lck_spin_t              *lck,
+       unsigned                int    type);
 
-extern boolean_t               lck_mtx_try_lock(
-                                                                       lck_mtx_t               *lck);
+extern boolean_t        kdp_lck_rw_lock_is_acquired_exclusive(
+       lck_rw_t                *lck);
 
-#endif /* KERNEL_PRIVATE */
+#endif  /* KERNEL_PRIVATE */
 
-extern void                            lck_mtx_assert(
-                                                                       lck_mtx_t               *lck,
-                                                                       unsigned int    type);
+extern void             lck_mtx_assert(
+       lck_mtx_t               *lck,
+       unsigned                int    type);
 
-__END_DECLS
+#if MACH_ASSERT
+#define LCK_MTX_ASSERT(lck, type) lck_mtx_assert((lck),(type))
+#define LCK_SPIN_ASSERT(lck, type) lck_spin_assert((lck),(type))
+#define LCK_RW_ASSERT(lck, type) lck_rw_assert((lck),(type))
+#else /* MACH_ASSERT */
+#define LCK_MTX_ASSERT(lck, type)
+#define LCK_SPIN_ASSERT(lck, type)
+#define LCK_RW_ASSERT(lck, type)
+#endif /* MACH_ASSERT */
 
-#define        LCK_MTX_ASSERT_OWNED    0x01
-#define        LCK_MTX_ASSERT_NOTOWNED 0x02
+#if DEBUG
+#define LCK_MTX_ASSERT_DEBUG(lck, type) lck_mtx_assert((lck),(type))
+#define LCK_SPIN_ASSERT_DEBUG(lck, type) lck_spin_assert((lck),(type))
+#define LCK_RW_ASSERT_DEBUG(lck, type) lck_rw_assert((lck),(type))
+#else /* DEBUG */
+#define LCK_MTX_ASSERT_DEBUG(lck, type)
+#define LCK_SPIN_ASSERT_DEBUG(lck, type)
+#define LCK_RW_ASSERT_DEBUG(lck, type)
+#endif /* DEBUG */
 
-#ifdef MACH_KERNEL_PRIVATE
-extern void                            lck_mtx_lock_wait(
-                                                                       lck_mtx_t               *lck,
-                                                                       thread_t                holder);
+#define LCK_ASSERT_OWNED                1
+#define LCK_ASSERT_NOTOWNED             2
 
-extern int                             lck_mtx_lock_acquire(
-                                                                       lck_mtx_t               *lck);
+#define LCK_MTX_ASSERT_OWNED    LCK_ASSERT_OWNED
+#define LCK_MTX_ASSERT_NOTOWNED LCK_ASSERT_NOTOWNED
 
-extern void                            lck_mtx_unlock_wakeup(
-                                                                       lck_mtx_t               *lck,
-                                                                       thread_t                holder);
+#ifdef  MACH_KERNEL_PRIVATE
+struct turnstile;
+extern void             lck_mtx_lock_wait(
+       lck_mtx_t               *lck,
+       thread_t                holder,
+       struct turnstile        **ts);
+
+extern int              lck_mtx_lock_acquire(
+       lck_mtx_t               *lck,
+       struct turnstile        *ts);
+
+extern  boolean_t       lck_mtx_unlock_wakeup(
+       lck_mtx_t               *lck,
+       thread_t                holder);
+
+extern boolean_t        lck_mtx_ilk_unlock(
+       lck_mtx_t               *lck);
+
+extern boolean_t        lck_mtx_ilk_try_lock(
+       lck_mtx_t               *lck);
+
+extern void lck_mtx_wakeup_adjust_pri(thread_t thread, integer_t priority);
 
-extern boolean_t               lck_mtx_ilk_unlock(
-                                                                       lck_mtx_t               *lck);
 #endif
 
-#define decl_lck_rw_data(class,name)     class lck_rw_t name;
+#define decl_lck_rw_data(class, name)     class lck_rw_t name
 
-typedef unsigned int    lck_rw_type_t;
+typedef unsigned int     lck_rw_type_t;
 
-#define        LCK_RW_TYPE_SHARED                      0x01
-#define        LCK_RW_TYPE_EXCLUSIVE           0x02
+#define LCK_RW_TYPE_SHARED                      0x01
+#define LCK_RW_TYPE_EXCLUSIVE           0x02
 
-__BEGIN_DECLS
+#ifdef XNU_KERNEL_PRIVATE
+#define LCK_RW_ASSERT_SHARED    0x01
+#define LCK_RW_ASSERT_EXCLUSIVE 0x02
+#define LCK_RW_ASSERT_HELD              0x03
+#define LCK_RW_ASSERT_NOTHELD   0x04
+#endif
+
+extern lck_rw_t         *lck_rw_alloc_init(
+       lck_grp_t               *grp,
+       lck_attr_t              *attr);
 
-extern lck_rw_t                        *lck_rw_alloc_init(
-                                                                       lck_grp_t               *grp,
-                                                                       lck_attr_t              *attr);
+extern void             lck_rw_init(
+       lck_rw_t                *lck,
+       lck_grp_t               *grp,
+       lck_attr_t              *attr);
 
-extern void                            lck_rw_init(
-                                                                       lck_rw_t                *lck, 
-                                                                       lck_grp_t               *grp,
-                                                                       lck_attr_t              *attr);
+extern void             lck_rw_lock(
+       lck_rw_t                *lck,
+       lck_rw_type_t           lck_rw_type);
 
-extern void                            lck_rw_lock(
-                                                                       lck_rw_t                *lck,
-                                                                       lck_rw_type_t   lck_rw_type);
+extern void             lck_rw_unlock(
+       lck_rw_t                *lck,
+       lck_rw_type_t           lck_rw_type);
 
-extern void                            lck_rw_unlock(
-                                                                       lck_rw_t                *lck,
-                                                                       lck_rw_type_t   lck_rw_type);
+extern void             lck_rw_lock_shared(
+       lck_rw_t                *lck);
 
-extern void                            lck_rw_lock_shared(
-                                                                       lck_rw_t                *lck);
+extern void             lck_rw_unlock_shared(
+       lck_rw_t                *lck);
 
-extern void                            lck_rw_unlock_shared(
-                                                                       lck_rw_t                *lck);
+extern boolean_t        lck_rw_lock_yield_shared(
+       lck_rw_t                *lck,
+       boolean_t               force_yield);
+
+extern void             lck_rw_lock_exclusive(
+       lck_rw_t                *lck);
+/*
+ *     Grabs the lock exclusive.
+ *     Returns true iff the thread spun or blocked while attempting to
+ *     acquire the lock.
+ *
+ *     Note that the return value is ONLY A HEURISTIC w.r.t. the lock's
+ *     contention.
+ *
+ *     This routine IS EXPERIMENTAL.
+ *     It's only used for the vm object lock, and use for other subsystems
+ *     is UNSUPPORTED.
+ */
+extern bool                             lck_rw_lock_exclusive_check_contended(
+       lck_rw_t                *lck);
+
+extern void             lck_rw_unlock_exclusive(
+       lck_rw_t                *lck);
+
+#ifdef  XNU_KERNEL_PRIVATE
+/*
+ * CAUTION
+ * read-write locks do not have a concept of ownership, so lck_rw_assert()
+ * merely asserts that someone is holding the lock, not necessarily the caller.
+ */
+extern void             lck_rw_assert(
+       lck_rw_t                *lck,
+       unsigned int            type);
 
-extern void                            lck_rw_lock_exclusive(
-                                                                       lck_rw_t                *lck);
+extern void lck_rw_clear_promotion(thread_t thread, uintptr_t trace_obj);
+extern void lck_rw_set_promotion_locked(thread_t thread);
 
-extern void                            lck_rw_unlock_exclusive(
-                                                                       lck_rw_t                *lck);
+uintptr_t unslide_for_kdebug(void* object);
+#endif /* XNU_KERNEL_PRIVATE */
 
-#ifdef KERNEL_PRIVATE
+#ifdef  KERNEL_PRIVATE
 
-extern lck_rw_type_t   lck_rw_done(
-                                                                       lck_rw_t                *lck);
+extern lck_rw_type_t    lck_rw_done(
+       lck_rw_t                *lck);
 #endif
 
-extern void                            lck_rw_destroy(
-                                                                       lck_rw_t                *lck,
-                                                                       lck_grp_t               *grp);
+extern void             lck_rw_destroy(
+       lck_rw_t                *lck,
+       lck_grp_t               *grp);
+
+extern void             lck_rw_free(
+       lck_rw_t                *lck,
+       lck_grp_t               *grp);
 
-extern void                            lck_rw_free(
-                                                                       lck_rw_t                *lck,
-                                                                       lck_grp_t               *grp);
+extern wait_result_t    lck_rw_sleep(
+       lck_rw_t                *lck,
+       lck_sleep_action_t      lck_sleep_action,
+       event_t                 event,
+       wait_interrupt_t        interruptible);
 
-extern wait_result_t   lck_rw_sleep(
-                                                                       lck_rw_t                        *lck,
-                                                                       lck_sleep_action_t      lck_sleep_action,
-                                                                       event_t                         event,
-                                                                       wait_interrupt_t        interruptible);
+extern wait_result_t    lck_rw_sleep_deadline(
+       lck_rw_t                *lck,
+       lck_sleep_action_t      lck_sleep_action,
+       event_t                 event,
+       wait_interrupt_t        interruptible,
+       uint64_t                deadline);
 
-extern wait_result_t   lck_rw_sleep_deadline(
-                                                                       lck_rw_t                        *lck,
-                                                                       lck_sleep_action_t      lck_sleep_action,
-                                                                       event_t                         event,
-                                                                       wait_interrupt_t        interruptible,
-                                                                       uint64_t                        deadline);
+extern boolean_t        lck_rw_lock_shared_to_exclusive(
+       lck_rw_t                *lck);
 
-#ifdef KERNEL_PRIVATE
+extern void             lck_rw_lock_exclusive_to_shared(
+       lck_rw_t                *lck);
 
-extern boolean_t               lck_rw_lock_shared_to_exclusive(
-                                                                       lck_rw_t                *lck);
+extern boolean_t        lck_rw_try_lock(
+       lck_rw_t                *lck,
+       lck_rw_type_t           lck_rw_type);
 
-extern void                            lck_rw_lock_exclusive_to_shared(
-                                                                       lck_rw_t                *lck);
+#ifdef  KERNEL_PRIVATE
 
-extern boolean_t               lck_rw_try_lock(
-                                                                       lck_rw_t                *lck,
-                                                                       lck_rw_type_t   lck_rw_type);
+extern boolean_t        lck_rw_try_lock_shared(
+       lck_rw_t                *lck);
 
-extern boolean_t               lck_rw_try_lock_shared(
-                                                                       lck_rw_t                *lck);
+extern boolean_t        lck_rw_try_lock_exclusive(
+       lck_rw_t                *lck);
 
-extern boolean_t               lck_rw_try_lock_exclusive(
-                                                                       lck_rw_t                *lck);
 #endif
+#if XNU_KERNEL_PRIVATE
+
+struct lck_attr_startup_spec {
+       lck_attr_t              *lck_attr;
+       uint32_t                lck_attr_set_flags;
+       uint32_t                lck_attr_clear_flags;
+};
+
+struct lck_spin_startup_spec {
+       lck_spin_t              *lck;
+       lck_grp_t               *lck_grp;
+       lck_attr_t              *lck_attr;
+};
+
+struct lck_mtx_startup_spec {
+       lck_mtx_t               *lck;
+       struct _lck_mtx_ext_    *lck_ext;
+       lck_grp_t               *lck_grp;
+       lck_attr_t              *lck_attr;
+};
+
+struct lck_rw_startup_spec {
+       lck_rw_t                *lck;
+       lck_grp_t               *lck_grp;
+       lck_attr_t              *lck_attr;
+};
+
+extern void             lck_attr_startup_init(
+       struct lck_attr_startup_spec *spec);
+
+extern void             lck_spin_startup_init(
+       struct lck_spin_startup_spec *spec);
+
+extern void             lck_mtx_startup_init(
+       struct lck_mtx_startup_spec *spec);
+
+extern void             lck_rw_startup_init(
+       struct lck_rw_startup_spec *spec);
+
+/*
+ * Auto-initializing locks declarations
+ * ------------------------------------
+ *
+ * Unless you need to configure your locks in very specific ways,
+ * there is no point creating explicit lock attributes. For most
+ * static locks, these declaration macros can be used:
+ *
+ * - LCK_SPIN_DECLARE for spinlocks,
+ * - LCK_MTX_EARLY_DECLARE for mutexes initialized before memory
+ *   allocations are possible,
+ * - LCK_MTX_DECLARE for mutexes,
+ * - LCK_RW_DECLARE for reader writer locks.
+ *
+ * For cases when some particular attributes need to be used,
+ * these come in *_ATTR variants that take a variable declared with
+ * LCK_ATTR_DECLARE as an argument.
+ */
+#define LCK_ATTR_DECLARE(var, set_flags, clear_flags) \
+       SECURITY_READ_ONLY_LATE(lck_attr_t) var; \
+       static __startup_data struct lck_attr_startup_spec \
+       __startup_lck_attr_spec_ ## var = { &var, set_flags, clear_flags }; \
+       STARTUP_ARG(LOCKS_EARLY, STARTUP_RANK_SECOND, lck_attr_startup_init, \
+           &__startup_lck_attr_spec_ ## var)
+
+#define LCK_SPIN_DECLARE_ATTR(var, grp, attr) \
+       lck_spin_t var; \
+       static __startup_data struct lck_spin_startup_spec \
+       __startup_lck_spin_spec_ ## var = { &var, grp, attr }; \
+       STARTUP_ARG(LOCKS_EARLY, STARTUP_RANK_FOURTH, lck_spin_startup_init, \
+           &__startup_lck_spin_spec_ ## var)
+
+#define LCK_SPIN_DECLARE(var, grp) \
+       LCK_SPIN_DECLARE_ATTR(var, grp, LCK_ATTR_NULL)
+
+#define LCK_MTX_DECLARE_ATTR(var, grp, attr) \
+       lck_mtx_t var; \
+       static __startup_data struct lck_mtx_startup_spec \
+       __startup_lck_mtx_spec_ ## var = { &var, NULL, grp, attr }; \
+       STARTUP_ARG(LOCKS, STARTUP_RANK_FIRST, lck_mtx_startup_init, \
+           &__startup_lck_mtx_spec_ ## var)
+
+#define LCK_MTX_DECLARE(var, grp) \
+       LCK_MTX_DECLARE_ATTR(var, grp, LCK_ATTR_NULL)
+
+#define LCK_MTX_EARLY_DECLARE_ATTR(var, grp, attr) \
+       lck_mtx_ext_t var ## _ext; \
+       lck_mtx_t var; \
+       static __startup_data struct lck_mtx_startup_spec \
+       __startup_lck_mtx_spec_ ## var = { &var, &var ## _ext, grp, attr }; \
+       STARTUP_ARG(LOCKS_EARLY, STARTUP_RANK_FOURTH, lck_mtx_startup_init, \
+           &__startup_lck_mtx_spec_ ## var)
+
+#define LCK_MTX_EARLY_DECLARE(var, grp) \
+       LCK_MTX_EARLY_DECLARE_ATTR(var, grp, LCK_ATTR_NULL)
+
+#define LCK_RW_DECLARE_ATTR(var, grp, attr) \
+       lck_rw_t var; \
+       static __startup_data struct lck_rw_startup_spec \
+       __startup_lck_rw_spec_ ## var = { &var, grp, attr }; \
+       STARTUP_ARG(LOCKS_EARLY, STARTUP_RANK_FOURTH, lck_rw_startup_init, \
+           &__startup_lck_rw_spec_ ## var)
+
+#define LCK_RW_DECLARE(var, grp) \
+       LCK_RW_DECLARE_ATTR(var, grp, LCK_ATTR_NULL)
+
+#endif /* XNU_KERNEL_PRIVATE */
 
 __END_DECLS