osfmk/i386/cswitch.s

   1 /*
   2  * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   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.
  11  *
  12  * This Original Code and all software distributed under the License are
  13  * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  14  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  15  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  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.
  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
  53 #include <cpus.h>
  54 #include <platforms.h>
  55
  56 #include <i386/asm.h>
  57 #include <i386/proc_reg.h>
  58 #include <assym.s>
  59
  60 #if     NCPUS > 1
  61
  62 #ifdef  SYMMETRY
  63 #include <sqt/asm_macros.h>
  64 #endif
  65
  66 #if     AT386
  67 #include <i386/AT386/mp/mp.h>
  68 #endif  /* AT386 */
  69
  70 #define CX(addr, reg)   addr(,reg,4)
  71
  72 #else   /* NCPUS == 1 */
  73
  74 #define CPU_NUMBER(reg)
  75 #define CX(addr,reg)    addr
  76
  77 #endif  /* NCPUS == 1 */
  78
  79 /*
  80  * Context switch routines for i386.
  81  */
  82
  83 Entry(Load_context)
  84         movl    S_ARG0,%ecx                     /* get thread */
  85         movl    TH_KERNEL_STACK(%ecx),%ecx      /* get kernel stack */
  86         lea     KERNEL_STACK_SIZE-IKS_SIZE-IEL_SIZE(%ecx),%edx
  87                                                 /* point to stack top */
  88         CPU_NUMBER(%eax)
  89         movl    %ecx,CX(EXT(active_stacks),%eax) /* store stack address */
  90         movl    %edx,CX(EXT(kernel_stack),%eax) /* store stack top */
  91
  92         movl    KSS_ESP(%ecx),%esp              /* switch stacks */
  93         movl    KSS_ESI(%ecx),%esi              /* restore registers */
  94         movl    KSS_EDI(%ecx),%edi
  95         movl    KSS_EBP(%ecx),%ebp
  96         movl    KSS_EBX(%ecx),%ebx
  97         xorl    %eax,%eax                       /* return zero (no old thread) */
  98         jmp     *KSS_EIP(%ecx)                  /* resume thread */
  99
 100 /*
 101  *      This really only has to save registers
 102  *      when there is no explicit continuation.
 103  */
 104
 105 Entry(Switch_context)
 106         CPU_NUMBER(%edx)
 107         movl    CX(EXT(active_stacks),%edx),%ecx /* get old kernel stack */
 108
 109         movl    %ebx,KSS_EBX(%ecx)              /* save registers */
 110         movl    %ebp,KSS_EBP(%ecx)
 111         movl    %edi,KSS_EDI(%ecx)
 112         movl    %esi,KSS_ESI(%ecx)
 113         popl    KSS_EIP(%ecx)                   /* save return PC */
 114         movl    %esp,KSS_ESP(%ecx)              /* save SP */
 115
 116         movl    0(%esp),%eax                    /* get old thread */
 117         movl    4(%esp),%ebx                    /* get continuation */
 118         movl    %ebx,TH_CONTINUATION(%eax)      /* save continuation */
 119         movl    %ecx,TH_KERNEL_STACK(%eax)      /* save kernel stack */
 120
 121         movl    8(%esp),%esi                    /* get new thread */
 122         movl    $ CPD_ACTIVE_THREAD,%ecx
 123         movl    %esi,%gs:(%ecx)                 /* new thread is active */
 124         movl    TH_KERNEL_STACK(%esi),%ecx      /* get its kernel stack */
 125         lea     KERNEL_STACK_SIZE-IKS_SIZE-IEL_SIZE(%ecx),%ebx
 126                                                 /* point to stack top */
 127
 128         movl    %ecx,CX(EXT(active_stacks),%edx) /* set current stack */
 129         movl    %ebx,CX(EXT(kernel_stack),%edx) /* set stack top */
 130
 131         movl    TH_TOP_ACT(%esi),%esi           /* get new_thread->top_act */
 132         cmpl    $0,ACT_KLOADED(%esi)            /* check kernel-loaded flag */
 133         je      0f
 134         movl    %esi,CX(EXT(active_kloaded),%edx)
 135         jmp     1f
 136 0:
 137         movl    $0,CX(EXT(active_kloaded),%edx)
 138 1:
 139         movl    KSS_ESP(%ecx),%esp              /* switch stacks */
 140         movl    KSS_ESI(%ecx),%esi              /* restore registers */
 141         movl    KSS_EDI(%ecx),%edi
 142         movl    KSS_EBP(%ecx),%ebp
 143         movl    KSS_EBX(%ecx),%ebx
 144         jmp     *KSS_EIP(%ecx)                  /* return old thread */
 145
 146 Entry(Thread_continue)
 147         pushl   %eax                            /* push the thread argument */
 148         xorl    %ebp,%ebp                       /* zero frame pointer */
 149         call    *%ebx                           /* call real continuation */
 150
 151 #if     NCPUS > 1
 152 /*
 153  * void switch_to_shutdown_context(thread_t thread,
 154  *                                 void (*routine)(processor_t),
 155  *                                 processor_t processor)
 156  *
 157  * saves the kernel context of the thread,
 158  * switches to the interrupt stack,
 159  * continues the thread (with thread_continue),
 160  * then runs routine on the interrupt stack.
 161  *
 162  * Assumes that the thread is a kernel thread (thus
 163  * has no FPU state)
 164  */
 165 Entry(switch_to_shutdown_context)
 166         CPU_NUMBER(%edx)
 167         movl    EXT(active_stacks)(,%edx,4),%ecx /* get old kernel stack */
 168         movl    %ebx,KSS_EBX(%ecx)              /* save registers */
 169         movl    %ebp,KSS_EBP(%ecx)
 170         movl    %edi,KSS_EDI(%ecx)
 171         movl    %esi,KSS_ESI(%ecx)
 172         popl    KSS_EIP(%ecx)                   /* save return PC */
 173         movl    %esp,KSS_ESP(%ecx)              /* save SP */
 174
 175         movl    0(%esp),%eax                    /* get old thread */
 176         movl    $0,TH_CONTINUATION(%eax)        /* clear continuation */
 177         movl    %ecx,TH_KERNEL_STACK(%eax)      /* save old stack */
 178         movl    4(%esp),%ebx                    /* get routine to run next */
 179         movl    8(%esp),%esi                    /* get its argument */
 180
 181         movl    CX(EXT(interrupt_stack),%edx),%ecx /* point to its intr stack */
 182         lea     INTSTACK_SIZE(%ecx),%esp        /* switch to it (top) */
 183
 184         pushl   %eax                            /* push thread */
 185         call    EXT(thread_dispatch)            /* reschedule thread */
 186         addl    $4,%esp                         /* clean stack */
 187
 188         pushl   %esi                            /* push argument */
 189         call    *%ebx                           /* call routine to run */
 190         hlt                                     /* (should never return) */
 191
 192 #endif  /* NCPUS > 1 */
 193
 194         .text
 195
 196         .globl  EXT(locore_end)
 197 LEXT(locore_end)
 198