[apple/xnu.git] / osfmk / i386 / cswitch.s

/*
 * 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) */
Commit	Line	Data
1c79356b	1	/*
2d21ac55	2	* Copyright (c) 2000-2006 Apple Computer, Inc. All rights reserved.
1c79356b	3	*
2d21ac55 A	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
8f6c56a5 A	20	* EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
8f6c56a5 A	21	* INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
2d21ac55 A	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.
8f6c56a5	25	*
2d21ac55	26	* @APPLE_OSREFERENCE_LICENSE_HEADER_END@
1c79356b A	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
1c79356b A	59	#include <platforms.h>
	60
	61	#include <i386/asm.h>
	62	#include <i386/proc_reg.h>
	63	#include <assym.s>
	64
1c79356b A	65	#ifdef SYMMETRY
	66	#include <sqt/asm_macros.h>
	67	#endif
	68
	69	#if AT386
55e303ae	70	#include <i386/mp.h>
1c79356b A	71	#endif /* AT386 */
	72
	73	#define CX(addr, reg) addr(,reg,4)
	74
0c530ab8	75	.text
1c79356b A	76	/*
	77	* Context switch routines for i386.
	78	*/
	79
	80	Entry(Load_context)
	81	movl S_ARG0,%ecx /* get thread */
	82	movl TH_KERNEL_STACK(%ecx),%ecx /* get kernel stack */
b0d623f7 A	83	lea -IKS_SIZE-IEL_SIZE(%ecx),%edx
b0d623f7 A	84	add EXT(kernel_stack_size),%edx /* point to stack top */
91447636 A	85	movl %ecx,%gs:CPU_ACTIVE_STACK /* store stack address */
	86	movl %edx,%gs:CPU_KERNEL_STACK /* store stack top */
	87
	88	movl %edx,%esp
	89	movl %edx,%ebp
1c79356b	90
b0d623f7	91	subl $12, %esp /* align stack */
1c79356b	92	xorl %eax,%eax /* return zero (no old thread) */
91447636 A	93	pushl %eax
91447636 A	94	call EXT(thread_continue)
1c79356b A	95
1c79356b A	96	/*
0c530ab8	97	* This has to save registers only
1c79356b A	98	* when there is no explicit continuation.
	99	*/
	100
	101	Entry(Switch_context)
0c530ab8	102	popl %eax /* pop return PC */
1c79356b	103
0c530ab8 A	104	/* Test for a continuation and skip all state saving if so... */
	105	cmpl $0,4(%esp)
	106	jne 5f
b0d623f7	107	movl %gs:CPU_KERNEL_STACK,%ecx /* get old kernel stack top */
1c79356b A	108	movl %ebx,KSS_EBX(%ecx) /* save registers */
	109	movl %ebp,KSS_EBP(%ecx)
	110	movl %edi,KSS_EDI(%ecx)
	111	movl %esi,KSS_ESI(%ecx)
0c530ab8	112	movl %eax,KSS_EIP(%ecx) /* save return PC */
1c79356b	113	movl %esp,KSS_ESP(%ecx) /* save SP */
0c530ab8	114	5:
55e303ae	115	movl 0(%esp),%eax /* return old thread */
b0d623f7 A	116	movl 8(%esp),%ecx /* get new thread */
	117	movl %ecx,%gs:CPU_ACTIVE_THREAD /* new thread is active */
	118	movl TH_KERNEL_STACK(%ecx),%ebx /* get its kernel stack */
	119	lea -IKS_SIZE-IEL_SIZE(%ebx),%ecx
	120	add EXT(kernel_stack_size),%ecx
1c79356b A	121	/* point to stack top */
1c79356b A	122
b0d623f7 A	123	movl %ebx,%gs:CPU_ACTIVE_STACK /* set current stack */
b0d623f7 A	124	movl %ecx,%gs:CPU_KERNEL_STACK /* set stack top */
1c79356b	125
0c530ab8	126
1c79356b A	127	movl KSS_ESP(%ecx),%esp /* switch stacks */
	128	movl KSS_ESI(%ecx),%esi /* restore registers */
	129	movl KSS_EDI(%ecx),%edi
	130	movl KSS_EBP(%ecx),%ebp
	131	movl KSS_EBX(%ecx),%ebx
	132	jmp KSS_EIP(%ecx) / return old thread */
	133
	134	Entry(Thread_continue)
b0d623f7	135	subl $12, %esp /* align stack */
1c79356b A	136	pushl %eax /* push the thread argument */
	137	xorl %ebp,%ebp /* zero frame pointer */
	138	call %ebx / call real continuation */
	139
1c79356b	140	/*
0c530ab8 A	141	* thread_t Shutdown_context(thread_t thread,
	142	* void (*routine)(processor_t),
	143	* processor_t processor)
1c79356b A	144	*
	145	* saves the kernel context of the thread,
	146	* switches to the interrupt stack,
	147	* continues the thread (with thread_continue),
	148	* then runs routine on the interrupt stack.
	149	*
1c79356b	150	*/
0c530ab8	151	Entry(Shutdown_context)
b0d623f7	152	movl %gs:CPU_KERNEL_STACK,%ecx /* get old kernel stack */
1c79356b A	153	movl %ebx,KSS_EBX(%ecx) /* save registers */
	154	movl %ebp,KSS_EBP(%ecx)
	155	movl %edi,KSS_EDI(%ecx)
	156	movl %esi,KSS_ESI(%ecx)
	157	popl KSS_EIP(%ecx) /* save return PC */
	158	movl %esp,KSS_ESP(%ecx) /* save SP */
	159
b0d623f7	160	movl %gs:CPU_ACTIVE_STACK,%ecx /* get old stack */
1c79356b	161	movl 0(%esp),%eax /* get old thread */
1c79356b A	162	movl %ecx,TH_KERNEL_STACK(%eax) /* save old stack */
	163	movl 4(%esp),%ebx /* get routine to run next */
	164	movl 8(%esp),%esi /* get its argument */
	165
91447636	166	movl %gs:CPU_INT_STACK_TOP,%esp /* switch to interrupt stack */
1c79356b	167
b0d623f7	168	subl $12, %esp /* align stack */
1c79356b A	169	pushl %esi /* push argument */
	170	call %ebx / call routine to run */
	171	hlt /* (should never return) */