1/* $NetBSD: lock_stubs.s,v 1.8 2008/05/25 15:56:12 chs Exp $ */ 2 3/*- 4 * Copyright (c) 2002, 2006 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * This code is derived from software contributed to The NetBSD Foundation 8 * by Jason R. Thorpe and Andrew Doran. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 29 * POSSIBILITY OF SUCH DAMAGE. 30 */ 31 32#include "opt_multiprocessor.h" 33#include "opt_lockdebug.h" 34 35#include <machine/param.h> 36#include <machine/asm.h> 37 38#include "assym.h" 39 40#undef CURLWP 41#define CURLWP (CPUINFO_VA+CI_CURLWP) 42 43#if defined(MULTIPROCESSOR) 44#define MB_READ membar #LoadLoad 45#define MB_MEM membar #LoadStore | #StoreStore 46#else 47#define MB_READ /* nothing */ 48#define MB_MEM /* nothing */ 49#endif 50 51#ifdef __arch64__ 52#define CASPTR casx 53#define LDPTR ldx 54#define STPTR stx 55#define CCCR %xcc 56#else 57#define CASPTR cas 58#define LDPTR ld 59#define STPTR st 60#define CCCR %icc 61#endif /* __arch64__ */ 62 63/* 64 * int _lock_cas(uintptr_t *ptr, uintptr_t old, uintptr_t new); 65 */ 66.align 32 67ENTRY(_lock_cas) 68 CASPTR [%o0], %o1, %o2 ! compare-and-swap 69 MB_MEM 70 xor %o1, %o2, %o2 ! expected == actual? 71 clr %o0 72 retl 73 movrz %o2, 1, %o0 74 75#if !defined(LOCKDEBUG) 76 77/* 78 * void mutex_enter(kmutex_t *); 79 */ 80.align 32 81ENTRY(mutex_enter) 82 sethi %hi(CURLWP), %o1 83 LDPTR [%o1 + %lo(CURLWP)], %o1 ! current thread 84 CASPTR [%o0], %g0, %o1 ! compare-and-swap 85 MB_READ 86 brnz,pn %o1, 1f ! lock was unowned? 87 nop 88 retl ! - yes, done 89 nop 901: ba _C_LABEL(mutex_vector_enter) ! nope, do it the 91 nop ! hard way 92 93/* 94 * void mutex_exit(kmutex_t *); 95 * 96 * XXX This should use a restartable sequence. See mutex_vector_enter(). 97 */ 98.align 32 99ENTRY(mutex_exit) 100 sethi %hi(CURLWP), %o1 101 LDPTR [%o1 + %lo(CURLWP)], %o1 ! current thread 102 clr %o2 ! new value (0) 103 MB_MEM 104 CASPTR [%o0], %o1, %o2 ! compare-and-swap 105 cmp %o1, %o2 106 bne,pn CCCR, 1f ! nope, hard case 107 nop 108 retl 109 nop 1101: ba _C_LABEL(mutex_vector_exit) 111 nop 112 113#endif /* !LOCKDEBUG */ 114