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

/*
 * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
 *
 * @APPLE_LICENSE_HEADER_START@
 * 
 * The contents of this file constitute Original Code as defined in and
 * are subject to the Apple Public Source License Version 1.1 (the
 * "License").  You may not use this file except in compliance with the
 * License.  Please obtain a copy of the License at
 * http://www.apple.com/publicsource and read it before using this file.
 * 
 * This 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 OR NON-INFRINGEMENT.  Please see the
 * License for the specific language governing rights and limitations
 * under the License.
 * 
 * @APPLE_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	KERNEL_STACK_SIZE-IKS_SIZE-IEL_SIZE(%ecx),%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

	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_ACTIVE_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)
	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),%ebx			/* get new thread */
	movl    %ebx,%gs:CPU_ACTIVE_THREAD      /* new thread is active */
	movl	TH_KERNEL_STACK(%ebx),%ecx	/* get its kernel stack */
	lea	KERNEL_STACK_SIZE-IKS_SIZE-IEL_SIZE(%ecx),%ebx
						/* point to stack top */

	movl	%ecx,%gs:CPU_ACTIVE_STACK	/* set current stack */
	movl	%ebx,%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)
	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_ACTIVE_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	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 */

	pushl	%esi				/* push argument */
	call	*%ebx				/* call routine to run */
	hlt					/* (should never return) */
Commit	Line	Data
1c79356b A	1	/*
	2	* Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
	3	*
	4	* @APPLE_LICENSE_HEADER_START@
	5	*
37839358 A	6	* The contents of this file constitute Original Code as defined in and
	7	* are subject to the Apple Public Source License Version 1.1 (the
	8	* "License"). You may not use this file except in compliance with the
	9	* License. Please obtain a copy of the License at
	10	* http://www.apple.com/publicsource and read it before using this file.
1c79356b	11	*
37839358 A	12	* This Original Code and all software distributed under the License are
37839358 A	13	* distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
1c79356b A	14	* EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
1c79356b A	15	* INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
37839358 A	16	* FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT. Please see the
	17	* License for the specific language governing rights and limitations
	18	* under the License.
1c79356b A	19	*
	20	* @APPLE_LICENSE_HEADER_END@
	21	*/
	22	/*
	23	* @OSF_COPYRIGHT@
	24	*/
	25	/*
	26	* Mach Operating System
	27	* Copyright (c) 1991,1990 Carnegie Mellon University
	28	* All Rights Reserved.
	29	*
	30	* Permission to use, copy, modify and distribute this software and its
	31	* documentation is hereby granted, provided that both the copyright
	32	* notice and this permission notice appear in all copies of the
	33	* software, derivative works or modified versions, and any portions
	34	* thereof, and that both notices appear in supporting documentation.
	35	*
	36	* CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
	37	* CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
	38	* ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
	39	*
	40	* Carnegie Mellon requests users of this software to return to
	41	*
	42	* Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
	43	* School of Computer Science
	44	* Carnegie Mellon University
	45	* Pittsburgh PA 15213-3890
	46	*
	47	* any improvements or extensions that they make and grant Carnegie Mellon
	48	* the rights to redistribute these changes.
	49	*/
	50	/*
	51	*/
	52
1c79356b A	53	#include <platforms.h>
	54
	55	#include <i386/asm.h>
	56	#include <i386/proc_reg.h>
	57	#include <assym.s>
	58
1c79356b A	59	#ifdef SYMMETRY
	60	#include <sqt/asm_macros.h>
	61	#endif
	62
	63	#if AT386
55e303ae	64	#include <i386/mp.h>
1c79356b A	65	#endif /* AT386 */
	66
	67	#define CX(addr, reg) addr(,reg,4)
	68
c0fea474	69	.text
1c79356b A	70	/*
	71	* Context switch routines for i386.
	72	*/
	73
	74	Entry(Load_context)
	75	movl S_ARG0,%ecx /* get thread */
	76	movl TH_KERNEL_STACK(%ecx),%ecx /* get kernel stack */
	77	lea KERNEL_STACK_SIZE-IKS_SIZE-IEL_SIZE(%ecx),%edx
	78	/* point to stack top */
91447636 A	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
1c79356b	84
1c79356b	85	xorl %eax,%eax /* return zero (no old thread) */
91447636 A	86	pushl %eax
91447636 A	87	call EXT(thread_continue)
1c79356b A	88
1c79356b A	89	/*
c0fea474	90	* This has to save registers only
1c79356b A	91	* when there is no explicit continuation.
	92	*/
	93
	94	Entry(Switch_context)
c0fea474	95	popl %eax /* pop return PC */
1c79356b	96
c0fea474 A	97	/* Test for a continuation and skip all state saving if so... */
	98	cmpl $0,4(%esp)
	99	jne 5f
	100	movl %gs:CPU_ACTIVE_STACK,%ecx /* get old kernel stack */
1c79356b A	101	movl %ebx,KSS_EBX(%ecx) /* save registers */
	102	movl %ebp,KSS_EBP(%ecx)
	103	movl %edi,KSS_EDI(%ecx)
	104	movl %esi,KSS_ESI(%ecx)
c0fea474	105	movl %eax,KSS_EIP(%ecx) /* save return PC */
1c79356b	106	movl %esp,KSS_ESP(%ecx) /* save SP */
c0fea474	107	5:
55e303ae	108	movl 0(%esp),%eax /* return old thread */
91447636	109	movl 8(%esp),%ebx /* get new thread */
c0fea474	110	movl %ebx,%gs:CPU_ACTIVE_THREAD /* new thread is active */
91447636	111	movl TH_KERNEL_STACK(%ebx),%ecx /* get its kernel stack */
1c79356b A	112	lea KERNEL_STACK_SIZE-IKS_SIZE-IEL_SIZE(%ecx),%ebx
	113	/* point to stack top */
	114
91447636 A	115	movl %ecx,%gs:CPU_ACTIVE_STACK /* set current stack */
91447636 A	116	movl %ebx,%gs:CPU_KERNEL_STACK /* set stack top */
1c79356b	117
c0fea474	118
1c79356b A	119	movl KSS_ESP(%ecx),%esp /* switch stacks */
	120	movl KSS_ESI(%ecx),%esi /* restore registers */
	121	movl KSS_EDI(%ecx),%edi
	122	movl KSS_EBP(%ecx),%ebp
	123	movl KSS_EBX(%ecx),%ebx
	124	jmp KSS_EIP(%ecx) / return old thread */
	125
	126	Entry(Thread_continue)
	127	pushl %eax /* push the thread argument */
	128	xorl %ebp,%ebp /* zero frame pointer */
	129	call %ebx / call real continuation */
	130
1c79356b	131	/*
c0fea474 A	132	* thread_t Shutdown_context(thread_t thread,
	133	* void (*routine)(processor_t),
	134	* processor_t processor)
1c79356b A	135	*
	136	* saves the kernel context of the thread,
	137	* switches to the interrupt stack,
	138	* continues the thread (with thread_continue),
	139	* then runs routine on the interrupt stack.
	140	*
1c79356b	141	*/
c0fea474	142	Entry(Shutdown_context)
91447636	143	movl %gs:CPU_ACTIVE_STACK,%ecx /* get old kernel stack */
1c79356b A	144	movl %ebx,KSS_EBX(%ecx) /* save registers */
	145	movl %ebp,KSS_EBP(%ecx)
	146	movl %edi,KSS_EDI(%ecx)
	147	movl %esi,KSS_ESI(%ecx)
	148	popl KSS_EIP(%ecx) /* save return PC */
	149	movl %esp,KSS_ESP(%ecx) /* save SP */
	150
	151	movl 0(%esp),%eax /* get old thread */
1c79356b A	152	movl %ecx,TH_KERNEL_STACK(%eax) /* save old stack */
	153	movl 4(%esp),%ebx /* get routine to run next */
	154	movl 8(%esp),%esi /* get its argument */
	155
91447636	156	movl %gs:CPU_INT_STACK_TOP,%esp /* switch to interrupt stack */
1c79356b A	157
	158	pushl %esi /* push argument */
	159	call %ebx / call routine to run */
	160	hlt /* (should never return) */