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      1 /*
      2  * CDDL HEADER START
      3  *
      4  * The contents of this file are subject to the terms of the
      5  * Common Development and Distribution License (the "License").
      6  * You may not use this file except in compliance with the License.
      7  *
      8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
      9  * or http://www.opensolaris.org/os/licensing.
     10  * See the License for the specific language governing permissions
     11  * and limitations under the License.
     12  *
     13  * When distributing Covered Code, include this CDDL HEADER in each
     14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
     15  * If applicable, add the following below this CDDL HEADER, with the
     16  * fields enclosed by brackets "[]" replaced with your own identifying
     17  * information: Portions Copyright [yyyy] [name of copyright owner]
     18  *
     19  * CDDL HEADER END
     20  */
     21 /*
     22  * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
     23  * Use is subject to license terms.
     24  */
     25 
     26 #ifndef _SYS_MUTEX_IMPL_H
     27 #define	_SYS_MUTEX_IMPL_H
     28 
     29 #ifndef	_ASM
     30 #include <sys/types.h>
     31 #include <sys/machlock.h>
     32 #endif
     33 
     34 #ifdef	__cplusplus
     35 extern "C" {
     36 #endif
     37 
     38 #ifndef	_ASM
     39 
     40 /*
     41  * mutex_enter() assumes that the mutex is adaptive and tries to grab the
     42  * lock by doing a atomic compare and exchange on the first word of the mutex.
     43  * If the compare and exchange fails, it means that either (1) the lock is a
     44  * spin lock, or (2) the lock is adaptive but already held.
     45  * mutex_vector_enter() distinguishes these cases by looking at the mutex
     46  * type, which is encoded in the low-order bits of the owner field.
     47  */
     48 typedef union mutex_impl {
     49 	/*
     50 	 * Adaptive mutex.
     51 	 */
     52 	struct adaptive_mutex {
     53 		uintptr_t _m_owner;	/* 0-3/0-7 owner and waiters bit */
     54 #ifndef _LP64
     55 		uintptr_t _m_filler;	/* 4-7 unused */
     56 #endif
     57 	} m_adaptive;
     58 
     59 	/*
     60 	 * Spin Mutex.
     61 	 */
     62 	struct spin_mutex {
     63 		lock_t	m_dummylock;	/* 0	dummy lock (always set) */
     64 		lock_t	m_spinlock;	/* 1	real lock */
     65 		ushort_t m_filler;	/* 2-3	unused */
     66 		ushort_t m_oldspl;	/* 4-5	old pil value */
     67 		ushort_t m_minspl;	/* 6-7	min pil val if lock held */
     68 	} m_spin;
     69 
     70 } mutex_impl_t;
     71 
     72 #define	m_owner	m_adaptive._m_owner
     73 
     74 #define	MUTEX_ALIGN	_LONG_ALIGNMENT
     75 #define	MUTEX_ALIGN_WARNINGS	10	/* num of warnings to issue */
     76 
     77 #define	MUTEX_WAITERS		0x1
     78 #define	MUTEX_DEAD		0x6
     79 #define	MUTEX_THREAD		(-0x8)
     80 
     81 #define	MUTEX_OWNER(lp)		((kthread_id_t)((lp)->m_owner & MUTEX_THREAD))
     82 #define	MUTEX_NO_OWNER		((kthread_id_t)NULL)
     83 
     84 #define	MUTEX_SET_WAITERS(lp)						\
     85 {									\
     86 	uintptr_t old;							\
     87 	while ((old = (lp)->m_owner) != 0 &&				\
     88 	    casip(&(lp)->m_owner, old, old | MUTEX_WAITERS) != old)	\
     89 		continue;						\
     90 }
     91 
     92 #define	MUTEX_HAS_WAITERS(lp)			((lp)->m_owner & MUTEX_WAITERS)
     93 #define	MUTEX_CLEAR_LOCK_AND_WAITERS(lp)	(lp)->m_owner = 0
     94 
     95 #define	MUTEX_SET_TYPE(lp, type)
     96 #define	MUTEX_TYPE_ADAPTIVE(lp)	(((lp)->m_owner & MUTEX_DEAD) == 0)
     97 #define	MUTEX_TYPE_SPIN(lp)	((lp)->m_spin.m_dummylock == LOCK_HELD_VALUE)
     98 
     99 #define	MUTEX_DESTROY(lp)	\
    100 	(lp)->m_owner = ((uintptr_t)curthread | MUTEX_DEAD)
    101 /* mutex backoff delay macro and constants  */
    102 #define	MUTEX_BACKOFF_BASE	1
    103 #define	MUTEX_BACKOFF_SHIFT	2
    104 #define	MUTEX_CAP_FACTOR	64
    105 #define	MUTEX_DELAY()	{	\
    106 			mutex_delay(); \
    107 			SMT_PAUSE();	\
    108 			}
    109 
    110 /* low overhead clock read */
    111 #define	MUTEX_GETTICK()	tsc_read()
    112 extern void null_xcall(void);
    113 #define	MUTEX_SYNC()	{	\
    114 			cpuset_t set;   \
    115 			CPUSET_ALL(set);        \
    116 			xc_call(0, 0, 0, CPUSET2BV(set),	\
    117 			    (xc_func_t)null_xcall); \
    118 		}
    119 
    120 extern int mutex_adaptive_tryenter(mutex_impl_t *);
    121 extern void *mutex_owner_running(mutex_impl_t *);
    122 
    123 #else	/* _ASM */
    124 
    125 #define	MUTEX_THREAD	-0x8
    126 
    127 #endif	/* _ASM */
    128 
    129 #ifdef	__cplusplus
    130 }
    131 #endif
    132 
    133 #endif	/* _SYS_MUTEX_IMPL_H */
    134