/* * Copyright (c) 2000-2006 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. 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 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT. * Please see the License for the specific language governing rights and * limitations under the License. * * @APPLE_OSREFERENCE_LICENSE_HEADER_END@ */ /* * @OSF_COPYRIGHT@ */ /* * Mach Operating System * Copyright (c) 1991,1990 Carnegie Mellon University * All Rights Reserved. * * Permission to use, copy, modify and distribute this software and its * documentation is hereby granted, provided that both the copyright * notice and this permission notice appear in all copies of the * software, derivative works or modified versions, and any portions * thereof, and that both notices appear in supporting documentation. * * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS" * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE. * * Carnegie Mellon requests users of this software to return to * * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU * School of Computer Science * Carnegie Mellon University * Pittsburgh PA 15213-3890 * * any improvements or extensions that they make and grant Carnegie Mellon * the rights to redistribute these changes. */ /* */ #include <platforms.h> #include <i386/asm.h> #include <i386/proc_reg.h> #include <assym.s> #ifdef SYMMETRY #include <sqt/asm_macros.h> #endif #if AT386 #include <i386/mp.h> #endif /* AT386 */ #define CX(addr, reg) addr(,reg,4) .text /* * Context switch routines for i386. */ Entry(Load_context) movl S_ARG0,%ecx /* get thread */ movl TH_KERNEL_STACK(%ecx),%ecx /* get kernel stack */ lea -IKS_SIZE-IEL_SIZE(%ecx),%edx add EXT(kernel_stack_size),%edx /* point to stack top */ movl %ecx,%gs:CPU_ACTIVE_STACK /* store stack address */ movl %edx,%gs:CPU_KERNEL_STACK /* store stack top */ movl %edx,%esp movl %edx,%ebp subl $12, %esp /* align stack */ xorl %eax,%eax /* return zero (no old thread) */ pushl %eax call EXT(thread_continue) /* * This has to save registers only * when there is no explicit continuation. */ Entry(Switch_context) popl %eax /* pop return PC */ /* Test for a continuation and skip all state saving if so... */ cmpl $0,4(%esp) jne 5f movl %gs:CPU_KERNEL_STACK,%ecx /* get old kernel stack top */ movl %ebx,KSS_EBX(%ecx) /* save registers */ movl %ebp,KSS_EBP(%ecx) movl %edi,KSS_EDI(%ecx) movl %esi,KSS_ESI(%ecx) movl %eax,KSS_EIP(%ecx) /* save return PC */ movl %esp,KSS_ESP(%ecx) /* save SP */ 5: movl 0(%esp),%eax /* return old thread */ movl 8(%esp),%ecx /* get new thread */ movl %ecx,%gs:CPU_ACTIVE_THREAD /* new thread is active */ movl TH_KERNEL_STACK(%ecx),%ebx /* get its kernel stack */ lea -IKS_SIZE-IEL_SIZE(%ebx),%ecx add EXT(kernel_stack_size),%ecx /* point to stack top */ movl %ebx,%gs:CPU_ACTIVE_STACK /* set current stack */ movl %ecx,%gs:CPU_KERNEL_STACK /* set stack top */ movl KSS_ESP(%ecx),%esp /* switch stacks */ movl KSS_ESI(%ecx),%esi /* restore registers */ movl KSS_EDI(%ecx),%edi movl KSS_EBP(%ecx),%ebp movl KSS_EBX(%ecx),%ebx jmp *KSS_EIP(%ecx) /* return old thread */ Entry(Thread_continue) subl $12, %esp /* align stack */ pushl %eax /* push the thread argument */ xorl %ebp,%ebp /* zero frame pointer */ call *%ebx /* call real continuation */ /* * thread_t Shutdown_context(thread_t thread, * void (*routine)(processor_t), * processor_t processor) * * saves the kernel context of the thread, * switches to the interrupt stack, * continues the thread (with thread_continue), * then runs routine on the interrupt stack. * */ Entry(Shutdown_context) movl %gs:CPU_KERNEL_STACK,%ecx /* get old kernel stack */ movl %ebx,KSS_EBX(%ecx) /* save registers */ movl %ebp,KSS_EBP(%ecx) movl %edi,KSS_EDI(%ecx) movl %esi,KSS_ESI(%ecx) popl KSS_EIP(%ecx) /* save return PC */ movl %esp,KSS_ESP(%ecx) /* save SP */ movl %gs:CPU_ACTIVE_STACK,%ecx /* get old stack */ movl 0(%esp),%eax /* get old thread */ movl %ecx,TH_KERNEL_STACK(%eax) /* save old stack */ movl 4(%esp),%ebx /* get routine to run next */ movl 8(%esp),%esi /* get its argument */ movl %gs:CPU_INT_STACK_TOP,%esp /* switch to interrupt stack */ subl $12, %esp /* align stack */ pushl %esi /* push argument */ call *%ebx /* call routine to run */ hlt /* (should never return) */