ntoskrnl/ke/arm/ctxswtch.s

   1 /*
   2  * PROJECT:         ReactOS Kernel
   3  * LICENSE:         BSD - See COPYING.ARM in the top level directory
   4  * FILE:            ntoskrnl/ke/arm/ctxswtch.s
   5  * PURPOSE:         Context Switch and Idle Thread on ARM
   6  * PROGRAMMERS:     ReactOS Portable Systems Group
   7  */
   8
   9     .title "ARM Context Switching"
  10     .include "ntoskrnl/include/internal/arm/kxarm.h"
  11     .include "ntoskrnl/include/internal/arm/ksarm.h"
  12
  13     TEXTAREA
  14     NESTED_ENTRY KiSwapContext
  15     PROLOG_END KiSwapContext
  16
  17         // BUSTEDDDD
  18         b .
  19
  20     //
  21     // a1 = Old Thread
  22     // a2 = New Thread
  23     //
  24
  25     //
  26     // Make space for the trap frame
  27     //
  28     sub sp, sp, #ExceptionFrameLength
  29
  30     //
  31     // Build exception frame
  32     // FIXME-PERF: Change to stmdb later
  33     //
  34     str r4, [sp, #ExR4]
  35     str r5, [sp, #ExR5]
  36     str r6, [sp, #ExR6]
  37     str r7, [sp, #ExR7]
  38     str r8, [sp, #ExR8]
  39     str r9, [sp, #ExR9]
  40     str r10, [sp, #ExR10]
  41     str r11, [sp, #ExR11]
  42     str lr, [sp, #ExLr]
  43     mrs r4, spsr_all
  44     str r4, [sp, #ExSpsr]
  45
  46     //
  47     // Switch stacks
  48     //
  49     str sp, [a1, #ThKernelStack]
  50     ldr sp, [a2, #ThKernelStack]
  51
  52     //
  53     // Call the C context switch code
  54     //
  55     bl KiSwapContextInternal
  56
  57     //
  58     // Get the SPSR and restore it
  59     //
  60     ldr r4, [sp, #ExSpsr]
  61     msr spsr_all, r4
  62
  63     //
  64     // Restore the registers
  65     // FIXME-PERF: Use LDMIA later
  66     //
  67     ldr r4, [sp, #ExR4]
  68     ldr r5, [sp, #ExR5]
  69     ldr r6, [sp, #ExR6]
  70     ldr r7, [sp, #ExR7]
  71     ldr r8, [sp, #ExR8]
  72     ldr r9, [sp, #ExR9]
  73     ldr r10, [sp, #ExR10]
  74     ldr r11, [sp, #ExR11]
  75     ldr lr, [sp, #ExLr]
  76
  77     //
  78     // Restore stack
  79     //
  80     add sp, sp, #ExceptionFrameLength
  81
  82     //
  83     // Jump to saved restore address
  84     //
  85     mov pc, lr
  86
  87     ENTRY_END KiSwapContext
  88
  89     NESTED_ENTRY KiThreadStartup
  90     PROLOG_END KiThreadStartup
  91
  92     //
  93     // Lower to APC_LEVEL
  94     //
  95     mov a1, #1
  96     bl KeLowerIrql
  97
  98     //
  99     // Set the start address and startup context
 100     //
 101     mov a1, r6
 102     mov a2, r5
 103     blx r7
 104
 105     //
 106     // Oh noes, we are back!
 107     //
 108     b .
 109
 110     ENTRY_END KiThreadStartup
 111
 112     NESTED_ENTRY KiSwitchThreads
 113     PROLOG_END KiSwitchThreads
 114
 115         // BUSTEDDDD
 116         b .
 117
 118     ENTRY_END KiSwitchThreads
 119
 120     NESTED_ENTRY KiSwapContextInternal
 121     PROLOG_END KiSwapContextInternal
 122
 123         // BUSTEDDDD
 124         b .
 125
 126     ENTRY_END KiSwapContextInternal