X-Git-Url: https://git.saurik.com/apple/xnu.git/blobdiff_plain/43866e378188c25dd1e2208016ab3cbeb086ae6c..6d2010ae8f7a6078e10b361c6962983bab233e0f:/osfmk/kern/simple_lock.h diff --git a/osfmk/kern/simple_lock.h b/osfmk/kern/simple_lock.h index 44436c742..576212175 100644 --- a/osfmk/kern/simple_lock.h +++ b/osfmk/kern/simple_lock.h @@ -1,16 +1,19 @@ /* - * Copyright (c) 2000 Apple Computer, Inc. All rights reserved. + * Copyright (c) 2000-2005 Apple Computer, Inc. All rights reserved. * - * @APPLE_LICENSE_HEADER_START@ - * - * Copyright (c) 1999-2003 Apple Computer, Inc. All Rights Reserved. + * @APPLE_OSREFERENCE_LICENSE_HEADER_START@ * * 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. Please obtain a copy of the License at - * http://www.opensource.apple.com/apsl/ and read it before using this - * file. + * 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. + * + * 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 @@ -20,7 +23,7 @@ * Please see the License for the specific language governing rights and * limitations under the License. * - * @APPLE_LICENSE_HEADER_END@ + * @APPLE_OSREFERENCE_LICENSE_HEADER_END@ */ /* * Copyright (C) 1998 Apple Computer @@ -59,269 +62,114 @@ * Author: Avadis Tevanian, Jr., Michael Wayne Young * Date: 1985 * - * Simple Locking primitives definitions + * Atomic primitives and Simple Locking primitives definitions */ -#ifndef _SIMPLE_LOCK_H_ -#define _SIMPLE_LOCK_H_ +#ifdef KERNEL_PRIVATE -/* - * Configuration variables: - * - * - * MACH_LDEBUG: record pc and thread of callers, turn on - * all lock debugging. - * - * - * ETAP: The Event Trace Analysis Package (ETAP) monitors - * and records micro-kernel lock behavior and general - * kernel events. ETAP supports two levels of - * tracing for locks: - * - cumulative (ETAP_LOCK_ACCUMULATE) - * - monitored (ETAP_LOCK_MONITOR) - * - * Note: If either level of tracing is configured then - * ETAP_LOCK_TRACE is automatically defined to - * equal one. - * - * Several macros are added throughout the lock code to - * allow for convenient configuration. - */ +#ifndef _KERN_SIMPLE_LOCK_H_ +#define _KERN_SIMPLE_LOCK_H_ +#include #include #include - -#include -#include -#include -#include - -/* - * The Mach lock package exports the following simple lock abstractions: - * - * Lock Type Properties - * hw_lock lowest level hardware abstraction; atomic, - * non-blocking, mutual exclusion; supports pre-emption - * usimple non-blocking spinning lock, available in all - * kernel configurations; may be used from thread - * and interrupt contexts; supports debugging, - * statistics and pre-emption - * simple non-blocking spinning lock, intended for SMP - * synchronization (vanishes on a uniprocessor); - * supports debugging, statistics and pre-emption - * - * NOTES TO IMPLEMENTORS: there are essentially two versions - * of the lock package. One is portable, written in C, and - * supports all of the various flavors of debugging, statistics, - * uni- versus multi-processor, pre-emption, etc. The "other" - * is whatever set of lock routines is provided by machine-dependent - * code. Presumably, the machine-dependent package is heavily - * optimized and meant for production kernels. - * - * We encourage implementors to focus on highly-efficient, - * production implementations of machine-dependent lock code, - * and use the portable lock package for everything else. - */ - -#include - -#ifdef __APPLE_API_PRIVATE +#include #ifdef MACH_KERNEL_PRIVATE +#include -/* - * Mach always initializes locks, even those statically - * allocated. - * - * The conditional acquisition call, hw_lock_try, - * must return non-zero on success and zero on failure. - * - * The hw_lock_held operation returns non-zero if the - * lock is set, zero if the lock is clear. This operation - * should be implemented using an ordinary memory read, - * rather than a special atomic instruction, allowing - * a processor to spin in cache waiting for the lock to - * be released without chewing up bus cycles. - */ -extern void hw_lock_init(hw_lock_t); -extern void hw_lock_lock(hw_lock_t); -extern void hw_lock_unlock(hw_lock_t); -extern unsigned int hw_lock_to(hw_lock_t, unsigned int); -extern unsigned int hw_lock_try(hw_lock_t); -extern unsigned int hw_lock_held(hw_lock_t); +extern void hw_lock_init( + hw_lock_t); -#endif /* MACH_KERNEL_PRIVATE */ +extern void hw_lock_lock( + hw_lock_t); -#endif /* __APPLE_API_PRIVATE */ +extern void hw_lock_unlock( + hw_lock_t); -/* - * Machine dependent ops. - */ -extern unsigned int hw_lock_bit(unsigned int *, unsigned int, unsigned int); -extern unsigned int hw_cpu_sync(unsigned int *, unsigned int); -extern unsigned int hw_cpu_wcng(unsigned int *, unsigned int, unsigned int); -extern unsigned int hw_lock_mbits(unsigned int *, unsigned int, unsigned int, - unsigned int, unsigned int); -void hw_unlock_bit(unsigned int *, unsigned int); +extern unsigned int hw_lock_to( + hw_lock_t, + unsigned int); -extern uint32_t hw_atomic_add( - uint32_t *dest, - uint32_t delt); +extern unsigned int hw_lock_try( + hw_lock_t); -extern uint32_t hw_atomic_sub( - uint32_t *dest, - uint32_t delt); +extern unsigned int hw_lock_held( + hw_lock_t); -extern uint32_t hw_atomic_or( - uint32_t *dest, - uint32_t mask); +#endif /* MACH_KERNEL_PRIVATE */ -extern uint32_t hw_atomic_and( - uint32_t *dest, - uint32_t mask); +__BEGIN_DECLS -extern uint32_t hw_compare_and_store( - uint32_t oldval, - uint32_t newval, - uint32_t *dest); +extern uint32_t hw_atomic_add( + volatile uint32_t *dest, + uint32_t delt); -extern void hw_queue_atomic(unsigned int *anchor, unsigned int *elem, unsigned int disp); -extern void hw_queue_atomic_list(unsigned int *anchor, unsigned int *first, unsigned int *last, unsigned int disp); -extern unsigned int *hw_dequeue_atomic(unsigned int *anchor, unsigned int disp); +extern uint32_t hw_atomic_sub( + volatile uint32_t *dest, + uint32_t delt); +extern uint32_t hw_atomic_or( + volatile uint32_t *dest, + uint32_t mask); -/* - * The remaining locking constructs may have two versions. - * One version is machine-independent, built in C on top of the - * hw_lock construct. This version supports production, debugging - * and statistics configurations and is portable across architectures. - * - * Any particular port may override some or all of the portable - * lock package for whatever reason -- usually efficiency. - * - * The direct use of hw_locks by machine-independent Mach code - * should be rare; the preferred spinning lock is the simple_lock - * (see below). - */ +extern uint32_t hw_atomic_and( + volatile uint32_t *dest, + uint32_t mask); /* - * A "simple" spin lock, providing non-blocking mutual - * exclusion and conditional acquisition. - * - * The usimple_lock exists even in uniprocessor configurations. - * A data structure is always allocated for it and the following - * operations are always defined: - * - * usimple_lock_init lock initialization (mandatory!) - * usimple_lock lock acquisition - * usimple_unlock lock release - * usimple_lock_try conditional lock acquisition; - * non-zero means success - * Simple lock DEBUG interfaces - * usimple_lock_held verify lock already held by me - * usimple_lock_none_held verify no usimple locks are held - * - * The usimple_lock may be used for synchronization between - * thread context and interrupt context, or between a uniprocessor - * and an intelligent device. Obviously, it may also be used for - * multiprocessor synchronization. Its use should be rare; the - * simple_lock is the preferred spinning lock (see below). - * - * The usimple_lock supports optional lock debugging and statistics. - * - * Normally, we expect the usimple_lock data structure to be - * defined here, with its operations implemented in an efficient, - * machine-dependent way. However, any implementation may choose - * to rely on a C-based, portable version of the usimple_lock for - * debugging, statistics, and/or tracing. Three hooks are used in - * the portable lock package to allow the machine-dependent package - * to override some or all of the portable package's features. - * - * The usimple_lock also handles pre-emption. Lock acquisition - * implies disabling pre-emption, while lock release implies - * re-enabling pre-emption. Conditional lock acquisition does - * not assume success: on success, pre-emption is disabled - * but on failure the pre-emption state remains the same as - * the pre-emption state before the acquisition attempt. + * Variant of hw_atomic_or which doesn't return a value; potentially + * more efficient on some platforms. */ - +extern void hw_atomic_or_noret( + volatile uint32_t *dest, + uint32_t mask); /* - * Each usimple_lock has a type, used for debugging and - * statistics. This type may safely be ignored in a - * production configuration. - * - * The conditional acquisition call, usimple_lock_try, - * must return non-zero on success and zero on failure. + * Variant of hw_atomic_and which doesn't return a value; potentially + * more efficient on some platforms. */ -extern void usimple_lock_init(usimple_lock_t,etap_event_t); -extern void usimple_lock(usimple_lock_t); -extern void usimple_unlock(usimple_lock_t); -extern unsigned int usimple_lock_try(usimple_lock_t); -extern void usimple_lock_held(usimple_lock_t); -extern void usimple_lock_none_held(void); +extern void hw_atomic_and_noret( + volatile uint32_t *dest, + uint32_t mask); -/* - * Upon the usimple_lock we define the simple_lock, which - * exists for SMP configurations. These locks aren't needed - * in a uniprocessor configuration, so compile-time tricks - * make them disappear when NCPUS==1. (For debugging purposes, - * however, they can be enabled even on a uniprocessor.) This - * should be the "most popular" spinning lock; the usimple_lock - * and hw_lock should only be used in rare cases. - * - * IMPORTANT: simple_locks that may be shared between interrupt - * and thread context must have their use coordinated with spl. - * The spl level must alway be the same when acquiring the lock. - * Otherwise, deadlock may result. - */ +extern uint32_t hw_compare_and_store( + uint32_t oldval, + uint32_t newval, + volatile uint32_t *dest); -#ifdef __APPLE_API_PRIVATE +extern void hw_queue_atomic( + unsigned int *anchor, + unsigned int *elem, + unsigned int disp); -#ifdef MACH_KERNEL_PRIVATE +extern void hw_queue_atomic_list( + unsigned int *anchor, + unsigned int *first, + unsigned int *last, + unsigned int disp); -#include -#include +extern unsigned int *hw_dequeue_atomic( + unsigned int *anchor, + unsigned int disp); -#if NCPUS == 1 && !ETAP_LOCK_TRACE && !USLOCK_DEBUG -/* - * MACH_RT is a very special case: in the case that the - * machine-dependent lock package hasn't taken responsibility - * but there is no other reason to turn on locks, if MACH_RT - * is turned on locks denote critical, non-preemptable points - * in the code. - * - * Otherwise, simple_locks may be layered directly on top of - * usimple_locks. - * - * N.B. The reason that simple_lock_try may be assumed to - * succeed under MACH_RT is that the definition only is used - * when NCPUS==1 AND because simple_locks shared between thread - * and interrupt context are always acquired with elevated spl. - * Thus, it is never possible to be interrupted in a dangerous - * way while holding a simple_lock. - */ -/* - * for locks and there is no other apparent reason to turn them on. - * So make them disappear. - */ -#define simple_lock_init(l,t) -#define simple_lock(l) disable_preemption() -#define simple_unlock(l) enable_preemption() -#define simple_lock_try(l) (disable_preemption(), 1) -#define simple_lock_addr(lock) ((simple_lock_t)0) -#define __slock_held_func__(l) preemption_is_disabled() -#endif /* NCPUS == 1 && !ETAP_LOCK_TRACE && !USLOCK_DEBUG */ +extern void usimple_lock_init( + usimple_lock_t, + unsigned short); -#if ETAP_LOCK_TRACE -extern void simple_lock_no_trace(simple_lock_t l); -extern int simple_lock_try_no_trace(simple_lock_t l); -extern void simple_unlock_no_trace(simple_lock_t l); -#endif /* ETAP_LOCK_TRACE */ +extern void usimple_lock( + usimple_lock_t); -#endif /* MACH_KERNEL_PRIVATE */ +extern void usimple_unlock( + usimple_lock_t); + +extern unsigned int usimple_lock_try( + usimple_lock_t); -#endif /* __APPLE_API_PRIVATE */ +__END_DECLS + +#define ETAP_NO_TRACE 0 +#define ETAP_IO_AHA 0 /* * If we got to here and we still don't have simple_lock_init @@ -334,37 +182,10 @@ extern void simple_unlock_no_trace(simple_lock_t l); #define simple_unlock(l) usimple_unlock(l) #define simple_lock_try(l) usimple_lock_try(l) #define simple_lock_addr(l) (&(l)) -#define __slock_held_func__(l) usimple_lock_held(l) #define thread_sleep_simple_lock(l, e, i) \ thread_sleep_usimple_lock((l), (e), (i)) -#endif / * !defined(simple_lock_init) */ - -#if USLOCK_DEBUG -/* - * Debug-time only: - * + verify that usimple_lock is already held by caller - * + verify that usimple_lock is NOT held by caller - * + verify that current processor owns no usimple_locks - * - * We do not provide a simple_lock_NOT_held function because - * it's impossible to verify when only MACH_RT is turned on. - * In that situation, only preemption is enabled/disabled - * around lock use, and it's impossible to tell which lock - * acquisition caused preemption to be disabled. However, - * note that it's still valid to use check_simple_locks - * when only MACH_RT is turned on -- no locks should be - * held, hence preemption should be enabled. - * Actually, the above isn't strictly true, as explicit calls - * to disable_preemption() need to be accounted for. - */ -#define simple_lock_held(l) __slock_held_func__(l) -#define check_simple_locks() usimple_lock_none_held() - -#else /* USLOCK_DEBUG */ - -#define simple_lock_held(l) -#define check_simple_locks() +#endif /* !defined(simple_lock_init) */ -#endif /* USLOCK_DEBUG */ +#endif /*!_KERN_SIMPLE_LOCK_H_*/ -#endif /*!_SIMPLE_LOCK_H_*/ +#endif /* KERNEL_PRIVATE */