reactos/ntoskrnl/ke/i386/ctxswitch.S

   1 /*
   2  * COPYRIGHT:       See COPYING in the top level directory
   3  * PROJECT:         ReactOS kernel
   4  * FILE:            ntoskrnl/ke/i386/ctxswitch.S
   5  * PURPOSE:         Thread Context Switching
   6  *
   7  * PROGRAMMERS:     Alex Ionescu (alex@relsoft.net)
   8  *                  Gregor Anich (FPU Code)
   9  */
  10
  11 /* INCLUDES ******************************************************************/
  12
  13 #include <asm.inc>
  14 #include <ks386.inc>
  15
  16 EXTERN @KiSwapContextEntry@8:PROC
  17 EXTERN @KiSwapContextExit@8:PROC
  18 EXTERN @KiRetireDpcList@4:PROC
  19 EXTERN @KiEnterV86Mode@4:PROC
  20 EXTERN @KiExitV86Mode@4:PROC
  21
  22 /* FUNCTIONS ****************************************************************/
  23 .code
  24
  25 PUBLIC @KiSwapContextInternal@0
  26 @KiSwapContextInternal@0:
  27     /* Build switch frame */
  28     sub esp, 2 * 4
  29     mov ecx, esp
  30     jmp @KiSwapContextEntry@8
  31
  32
  33 PUBLIC @KiSwapContext@8
  34 @KiSwapContext@8:
  35     /* Save 4 registers */
  36     sub esp, 4 * 4
  37
  38     /* Save all the non-volatile ones */
  39     mov [esp+12], ebx
  40     mov [esp+8], esi
  41     mov [esp+4], edi
  42     mov [esp+0], ebp
  43
  44     /* Get the wait IRQL */
  45     or dl, cl
  46
  47     /* Do the swap with the registers correctly setup */
  48     call @KiSwapContextInternal@0
  49
  50     /* Return the registers */
  51     mov ebp, [esp+0]
  52     mov edi, [esp+4]
  53     mov esi, [esp+8]
  54     mov ebx, [esp+12]
  55
  56     /* Clean stack */
  57     add esp, 4 * 4
  58     ret
  59
  60
  61 PUBLIC @KiSwitchThreads@8
  62 @KiSwitchThreads@8:
  63     /* Load the new kernel stack and switch OS to new thread */
  64     mov esp, edx
  65     call @KiSwapContextExit@8
  66
  67     /* Now we're on the new thread. Return to the caller to restore registers */
  68     add esp, 2 * 4
  69     ret
  70
  71
  72 PUBLIC @KiRetireDpcListInDpcStack@8
  73 @KiRetireDpcListInDpcStack@8:
  74     /* Switch stacks and retire DPCs */
  75     mov eax, esp
  76     mov esp, edx
  77     push eax
  78     call @KiRetireDpcList@4
  79
  80     /* Return on original stack */
  81     pop esp
  82     ret
  83
  84 PUBLIC _Ki386EnableCurrentLargePage@8
  85 _Ki386EnableCurrentLargePage@8:
  86     /* Save StartAddress in eax */
  87     mov eax, [esp + 4]
  88
  89     /* Save new CR3 value in ecx */
  90     mov ecx, [esp + 8]
  91
  92     /* Save flags value */
  93     pushfd
  94
  95     /* Disable interrupts */
  96     cli
  97
  98     /* Compute linear address */
  99     sub eax, offset _Ki386EnableCurrentLargePage@8
 100     add eax, offset _Ki386LargePageIdentityLabel
 101
 102     /* Save old CR3 in edx and replace with a new one */
 103     mov edx, cr3
 104     mov cr3, ecx
 105
 106     /* Jump to the next instruction but in linear mapping */
 107     jmp eax
 108
 109 _Ki386LargePageIdentityLabel:
 110     /* Disable paging */
 111     mov eax, cr0
 112     and eax, NOT CR0_PG
 113     mov cr0, eax
 114
 115     /* Jump to the next instruction to clear the prefetch queue */
 116     jmp $+2
 117
 118     /* Enable Page Size Extension in CR4 */
 119     mov ecx, cr4
 120     or ecx, CR4_PSE
 121     mov cr4, ecx
 122
 123     /* Done, now re-enable paging */
 124     or eax, CR0_PG
 125     mov cr0, eax
 126
 127     /* Jump to virtual address */
 128     mov eax, offset VirtualSpace
 129     jmp eax
 130
 131 VirtualSpace:
 132     /* Restore CR3 contents */
 133     mov cr3, edx
 134
 135     /* Restore flags */
 136     popfd
 137
 138     ret 8
 139
 140 /* FIXFIX: Move to C code ****/
 141 PUBLIC _Ki386SetupAndExitToV86Mode@4
 142 _Ki386SetupAndExitToV86Mode@4:
 143
 144     /* Enter V8086 mode */
 145     pushad
 146     sub esp, (12 + KTRAP_FRAME_LENGTH + NPX_FRAME_LENGTH + 16)
 147     mov ecx, esp
 148     call @KiEnterV86Mode@4
 149     jmp $
 150
 151
 152 PUBLIC @Ki386BiosCallReturnAddress@4
 153 @Ki386BiosCallReturnAddress@4:
 154
 155     /* Exit V8086 mode */
 156     call @KiExitV86Mode@4
 157     mov esp, eax
 158     add esp, (12 + KTRAP_FRAME_LENGTH + NPX_FRAME_LENGTH + 16)
 159     popad
 160     ret 4
 161
 162 END