1/* 2 * Copyright (c) 2000-2006 Apple Computer, Inc. All rights reserved. 3 * 4 * @APPLE_OSREFERENCE_LICENSE_HEADER_START@ 5 * 6 * This file contains Original Code and/or Modifications of Original Code 7 * as defined in and that are subject to the Apple Public Source License 8 * Version 2.0 (the 'License'). You may not use this file except in 9 * compliance with the License. The rights granted to you under the License 10 * may not be used to create, or enable the creation or redistribution of, 11 * unlawful or unlicensed copies of an Apple operating system, or to 12 * circumvent, violate, or enable the circumvention or violation of, any 13 * terms of an Apple operating system software license agreement. 14 * 15 * Please obtain a copy of the License at 16 * http://www.opensource.apple.com/apsl/ and read it before using this file. 17 * 18 * The Original Code and all software distributed under the License are 19 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER 20 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, 21 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, 22 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT. 23 * Please see the License for the specific language governing rights and 24 * limitations under the License. 25 * 26 * @APPLE_OSREFERENCE_LICENSE_HEADER_END@ 27 */ 28/* 29 * @OSF_COPYRIGHT@ 30 */ 31/* 32 * Mach Operating System 33 * Copyright (c) 1991,1990 Carnegie Mellon University 34 * All Rights Reserved. 35 * 36 * Permission to use, copy, modify and distribute this software and its 37 * documentation is hereby granted, provided that both the copyright 38 * notice and this permission notice appear in all copies of the 39 * software, derivative works or modified versions, and any portions 40 * thereof, and that both notices appear in supporting documentation. 41 * 42 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS" 43 * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR 44 * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE. 45 * 46 * Carnegie Mellon requests users of this software to return to 47 * 48 * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU 49 * School of Computer Science 50 * Carnegie Mellon University 51 * Pittsburgh PA 15213-3890 52 * 53 * any improvements or extensions that they make and grant Carnegie Mellon 54 * the rights to redistribute these changes. 55 */ 56/* 57 */ 58 59#include <platforms.h> 60 61#include <i386/asm.h> 62#include <i386/proc_reg.h> 63#include <i386/mp.h> 64#include <assym.s> 65 66 67#define CX(addr, reg) addr(,reg,4) 68 69 .text 70/* 71 * Context switch routines for i386. 72 */ 73 74Entry(Load_context) 75 movl S_ARG0,%ecx /* get thread */ 76 movl TH_KERNEL_STACK(%ecx),%ecx /* get kernel stack */ 77 lea -IKS_SIZE(%ecx),%edx 78 add EXT(kernel_stack_size),%edx /* point to stack top */ 79 movl %ecx,%gs:CPU_ACTIVE_STACK /* store stack address */ 80 movl %edx,%gs:CPU_KERNEL_STACK /* store stack top */ 81 82 movl %edx,%esp 83 movl %edx,%ebp 84 85 subl $12, %esp /* align stack */ 86 xorl %eax,%eax /* return zero (no old thread) */ 87 pushl %eax 88 call EXT(thread_continue) 89 90/* 91 * This has to save registers only 92 * when there is no explicit continuation. 93 */ 94 95Entry(Switch_context) 96 popl %eax /* pop return PC */ 97 98 /* Test for a continuation and skip all state saving if so... */ 99 cmpl $0,4(%esp) 100 jne 5f 101 movl %gs:CPU_KERNEL_STACK,%ecx /* get old kernel stack top */ 102 movl %ebx,KSS_EBX(%ecx) /* save registers */ 103 movl %ebp,KSS_EBP(%ecx) 104 movl %edi,KSS_EDI(%ecx) 105 movl %esi,KSS_ESI(%ecx) 106 movl %eax,KSS_EIP(%ecx) /* save return PC */ 107 movl %esp,KSS_ESP(%ecx) /* save SP */ 1085: 109 movl 0(%esp),%eax /* return old thread */ 110 movl 8(%esp),%ecx /* get new thread */ 111 movl %ecx,%gs:CPU_ACTIVE_THREAD /* new thread is active */ 112 movl TH_KERNEL_STACK(%ecx),%ebx /* get its kernel stack */ 113 lea -IKS_SIZE(%ebx),%ecx 114 add EXT(kernel_stack_size),%ecx 115 /* point to stack top */ 116 117 movl %ebx,%gs:CPU_ACTIVE_STACK /* set current stack */ 118 movl %ecx,%gs:CPU_KERNEL_STACK /* set stack top */ 119 120 121 movl KSS_ESP(%ecx),%esp /* switch stacks */ 122 movl KSS_ESI(%ecx),%esi /* restore registers */ 123 movl KSS_EDI(%ecx),%edi 124 movl KSS_EBP(%ecx),%ebp 125 movl KSS_EBX(%ecx),%ebx 126 jmp *KSS_EIP(%ecx) /* return old thread */ 127 128Entry(Thread_continue) 129 subl $12, %esp /* align stack */ 130 pushl %eax /* push the thread argument */ 131 xorl %ebp,%ebp /* zero frame pointer */ 132 call *%ebx /* call real continuation */ 133 134/* 135 * thread_t Shutdown_context(thread_t thread, 136 * void (*routine)(processor_t), 137 * processor_t processor) 138 * 139 * saves the kernel context of the thread, 140 * switches to the interrupt stack, 141 * continues the thread (with thread_continue), 142 * then runs routine on the interrupt stack. 143 * 144 */ 145Entry(Shutdown_context) 146 movl %gs:CPU_KERNEL_STACK,%ecx /* get old kernel stack */ 147 movl %ebx,KSS_EBX(%ecx) /* save registers */ 148 movl %ebp,KSS_EBP(%ecx) 149 movl %edi,KSS_EDI(%ecx) 150 movl %esi,KSS_ESI(%ecx) 151 popl KSS_EIP(%ecx) /* save return PC */ 152 movl %esp,KSS_ESP(%ecx) /* save SP */ 153 154 movl %gs:CPU_ACTIVE_STACK,%ecx /* get old stack */ 155 movl 0(%esp),%eax /* get old thread */ 156 movl %ecx,TH_KERNEL_STACK(%eax) /* save old stack */ 157 movl 4(%esp),%ebx /* get routine to run next */ 158 movl 8(%esp),%esi /* get its argument */ 159 160 movl %gs:CPU_INT_STACK_TOP,%esp /* switch to interrupt stack */ 161 162 subl $12, %esp /* align stack */ 163 pushl %esi /* push argument */ 164 call *%ebx /* call routine to run */ 165 hlt /* (should never return) */ 166