reactos/ntoskrnl/ke/i386/tskswitch.S

   1 /*
   2  *  ReactOS kernel
   3  *  Copyright (C) 2000 David Welch <welch@cwcom.net>
   4  *
   5  *  This program is free software; you can redistribute it and/or modify
   6  *  it under the terms of the GNU General Public License as published by
   7  *  the Free Software Foundation; either version 2 of the License, or
   8  *  (at your option) any later version.
   9  *
  10  *  This program is distributed in the hope that it will be useful,
  11  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  *  GNU General Public License for more details.
  14  *
  15  *  You should have received a copy of the GNU General Public License
  16  *  along with this program; if not, write to the Free Software
  17  *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  18  */
  19 /*
  20  * FILE:            ntoskrnl/ke/i386/tskswitch.S
  21  * PURPOSE:         Microkernel thread support
  22  * PROGRAMMER:      David Welch (welch@cwcom.net)
  23  * UPDATE HISTORY:
  24  *                  Created 09/10/00
  25  */
  26
  27 /* INCLUDES ******************************************************************/
  28
  29 #include <internal/i386/segment.h>
  30 #include <internal/ps.h>
  31 #include <ntos/tss.h>
  32 #include <internal/ntoskrnl.h>
  33
  34 /* FUNCTIONS ****************************************************************/
  35
  36 .globl _Ki386ContextSwitch
  37 _Ki386ContextSwitch:
  38 /*
  39  * FUNCTIONS: Switches to another thread's context
  40  * ARGUMENTS:
  41  *        Thread = Thread to switch to
  42  *        OldThread = Thread to switch from
  43  */
  44         pushl   %ebp
  45         movl    %esp, %ebp
  46
  47         /*
  48          * Save callee save registers.
  49          */
  50         pushl   %ebx
  51         pushl   %esi
  52         pushl   %edi
  53
  54         /*
  55          * This is a critical section for this processor.
  56          */
  57         cli
  58
  59         /*
  60          * Get the pointer to the new thread.
  61          */
  62         movl    8(%ebp), %ebx
  63
  64         /*
  65          * Set the base of the TEB selector to the base of the TEB for
  66          * this thread.
  67          */
  68         pushl   %ebx
  69         pushl   KTHREAD_TEB(%ebx)
  70         pushl   $TEB_SELECTOR
  71         call    _KeSetBaseGdtSelector
  72         addl    $8, %esp
  73         popl    %ebx
  74
  75         /*
  76          * Load the PCR selector.
  77          */
  78         movl    $PCR_SELECTOR, %eax
  79         movl    %eax, %fs
  80
  81         /*
  82          * Set the current thread information in the PCR.
  83          */
  84         movl    %ebx, %fs:KPCR_CURRENT_THREAD
  85
  86         /*
  87          * Set the current LDT
  88          */
  89         xorl    %eax, %eax
  90         movl    KTHREAD_APCSTATE_PROCESS(%ebx), %edi
  91         testw   $0xFFFF, KPROCESS_LDT_DESCRIPTOR0(%edi)
  92         jz      .L4
  93
  94         pushl   KPROCESS_LDT_DESCRIPTOR1(%edi)
  95         pushl   KPROCESS_LDT_DESCRIPTOR0(%edi)
  96         pushl   $LDT_SELECTOR
  97         call    _KeSetGdtSelector
  98         addl    $12, %esp
  99
 100         movl    $LDT_SELECTOR, %eax
 101
 102 .L4:
 103         lldtw   %ax
 104
 105         /*
 106          * Load up the iomap offset for this thread in
 107          * preparation for setting it below.
 108          */
 109         movl    KPROCESS_IOPM_OFFSET(%edi), %eax
 110
 111         /*
 112          * FIXME: Save debugging state.
 113          */
 114
 115         /*
 116          * FIXME: Save floating point state.
 117          */
 118
 119         /*
 120          * Switch stacks
 121          */
 122         movl    12(%ebp), %ebx
 123         movl    %esp, KTHREAD_KERNEL_STACK(%ebx)
 124         movl    8(%ebp), %ebx
 125         movl    KTHREAD_KERNEL_STACK(%ebx), %esp
 126         movl    KTHREAD_STACK_LIMIT(%ebx), %edi
 127
 128         /*
 129          * Set the stack pointer in this processors TSS
 130          */
 131         movl    %fs:KPCR_TSS, %esi
 132
 133         /*
 134          * Set current IOPM offset in the TSS
 135          */
 136         movw    %ax, KTSS_IOMAPBASE(%esi)
 137
 138         movl    KTHREAD_INITIAL_STACK(%ebx), %eax
 139         movl    %eax, KTSS_ESP0(%esi)
 140
 141         /*
 142          * Change the address space
 143          */
 144         movl    KTHREAD_APCSTATE_PROCESS(%ebx), %ebx
 145         movl    KPROCESS_DIRECTORY_TABLE_BASE(%ebx), %eax
 146         movl    %eax, %cr3
 147
 148         /*
 149          * FIXME: Restore floating point state
 150          */
 151
 152         /*
 153          * FIXME: Restore debugging state
 154          */
 155
 156         /*
 157          * Exit the critical section
 158          */
 159         sti
 160
 161         push    $_PiThreadLock
 162         call    _KeReleaseSpinLockFromDpcLevel@4
 163
 164         cmpl    $0, _PiNrThreadsAwaitingReaping
 165         je      .L3
 166         call    _PiWakeupReaperThread@0
 167 .L3:
 168
 169         /*
 170          * Restore the saved register and exit
 171          */
 172         popl    %edi
 173         popl    %esi
 174         popl    %ebx
 175
 176         popl    %ebp
 177         ret