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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 2007 Sun Microsystems, Inc.  All rights reserved.
     23  * Use is subject to license terms.
     24  */
     25 
     26 #ifndef _SYS_MACHLOCK_H
     27 #define	_SYS_MACHLOCK_H
     28 
     29 #pragma ident	"%Z%%M%	%I%	%E% SMI"
     30 
     31 #ifdef	__cplusplus
     32 extern "C" {
     33 #endif
     34 
     35 #ifndef	_ASM
     36 
     37 #include <sys/types.h>
     38 
     39 #ifdef _KERNEL
     40 
     41 extern void	lock_set(lock_t *lp);
     42 extern int	lock_try(lock_t *lp);
     43 extern int	lock_spin_try(lock_t *lp);
     44 extern int	ulock_try(lock_t *lp);
     45 extern void	ulock_clear(lock_t *lp);
     46 extern void	lock_clear(lock_t *lp);
     47 extern void	lock_set_spl(lock_t *lp, int new_pil, ushort_t *old_pil);
     48 extern void	lock_clear_splx(lock_t *lp, int s);
     49 
     50 #endif	/* _KERNEL */
     51 
     52 #define	LOCK_HELD_VALUE		0xff
     53 #define	LOCK_INIT_CLEAR(lp)	(*(lp) = 0)
     54 #define	LOCK_INIT_HELD(lp)	(*(lp) = LOCK_HELD_VALUE)
     55 #define	LOCK_HELD(lp)		(*(volatile lock_t *)(lp) != 0)
     56 
     57 typedef	lock_t	disp_lock_t;		/* dispatcher lock type */
     58 
     59 /*
     60  * SPIN_LOCK() macro indicates whether lock is implemented as a spin lock or
     61  * an adaptive mutex, depending on what interrupt levels use it.
     62  */
     63 #define	SPIN_LOCK(pl)	((pl) > ipltospl(LOCK_LEVEL))
     64 
     65 /*
     66  * Macro to control loops which spin on a lock and then check state
     67  * periodically.  Its passed an integer, and returns a boolean value
     68  * that if true indicates its a good time to get the scheduler lock and
     69  * check the state of the current owner of the lock.
     70  */
     71 #define	LOCK_SAMPLE_INTERVAL(i)	(((i) & 0xff) == 0)
     72 
     73 /*
     74  * Extern for CLOCK_LOCK.
     75  */
     76 extern	volatile int	hres_lock;
     77 
     78 #endif	/* _ASM */
     79 
     80 /*
     81  * The definitions of the symbolic interrupt levels:
     82  *
     83  *   CLOCK_LEVEL =>  The level at which one must be to block the clock.
     84  *
     85  *   LOCK_LEVEL  =>  The highest level at which one may block (and thus the
     86  *                   highest level at which one may acquire adaptive locks)
     87  *                   Also the highest level at which one may be preempted.
     88  *
     89  *   DISP_LEVEL  =>  The level at which one must be to perform dispatcher
     90  *                   operations.
     91  *
     92  * The constraints on the platform:
     93  *
     94  *  - CLOCK_LEVEL must be less than or equal to LOCK_LEVEL
     95  *  - LOCK_LEVEL must be less than DISP_LEVEL
     96  *  - DISP_LEVEL should be as close to LOCK_LEVEL as possible
     97  *
     98  * Note that LOCK_LEVEL and CLOCK_LEVEL have historically always been equal;
     99  * changing this relationship is probably possible but not advised.
    100  *
    101  */
    102 #define	CLOCK_LEVEL	10
    103 #define	LOCK_LEVEL	10
    104 #define	DISP_LEVEL	(LOCK_LEVEL + 1)
    105 
    106 #define	HIGH_LEVELS	(PIL_MAX - LOCK_LEVEL)
    107 
    108 #define	PIL_MAX		15
    109 
    110 /*
    111  * The mutex and semaphore code depends on being able to represent a lock
    112  * plus owner in a single 32-bit word.  Thus the owner must contain at most
    113  * 24 significant bits.  At present only threads, mutexes and semaphores
    114  * must be aware of this vile constraint.  Different ISAs may handle this
    115  * differently depending on their capabilities (e.g. compare-and-swap)
    116  * and limitations (e.g. constraints on alignment and/or KERNELBASE).
    117  */
    118 #define	PTR24_LSB	5			/* lower bits all zero */
    119 #define	PTR24_MSB	(PTR24_LSB + 24)	/* upper bits all one */
    120 #define	PTR24_ALIGN	32		/* minimum alignment (1 << lsb) */
    121 #define	PTR24_BASE	0xe0000000	/* minimum ptr value (-1 >> (32-msb)) */
    122 
    123 #ifdef	__cplusplus
    124 }
    125 #endif
    126 
    127 #endif	/* _SYS_MACHLOCK_H */
    128