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:     Timo Kreuzer (timo.kreuzer@reactos.org)
   7  *                  ReactOS Portable Systems Group
   8  */
   9
  10 #include <ksarm.h>
  11
  12     IMPORT KeLowerIrql
  13
  14     TEXTAREA
  15
  16 /*!
  17  * \name KiSwapContextInternal
  18  *
  19  * \brief
  20  *     The KiSwapContextInternal routine switches context to another thread.
  21  *
  22  * \param r0
  23  *     Pointer to the KTHREAD to which the caller wishes to switch to.
  24  *
  25  * \param r1
  26  *     Pointer to the KTHREAD to which the caller wishes to switch from.
  27  *
  28  * \param r2
  29  *     APC bypass
  30  *
  31  * \return
  32  *     None.
  33  *
  34  * \remarks
  35  *     ...
  36  *
  37  *--*/
  38     NESTED_ENTRY KiSwapContextInternal
  39
  40     /* Push a KSWITCH_FRAME on the stack */
  41     stmdb sp!,{r2,r3,r11,lr} // FIXME: what is the 2nd field?
  42     // PROLOG_PUSH {r2,r3,r11,lr}
  43
  44     PROLOG_END KiSwapContextInternal
  45
  46     /* Save kernel stack of old thread */
  47     str sp, [r1, #ThKernelStack]
  48
  49     /* Save new thread in R11 */
  50     mov r11, r0
  51
  52     //bl KiSwapContextSuspend
  53     __debugbreak
  54
  55     /* Load stack of new thread */
  56     ldr sp, [r11, #ThKernelStack]
  57
  58     /* Reload APC bypass */
  59     ldr r2, [sp, #SwApcBypass]
  60
  61     //bl KiSwapContextResume
  62     __debugbreak
  63
  64     /* Restore R2, R11 and return */
  65     ldmia sp!,{r2,r3,r11,pc}
  66
  67     NESTED_END KiSwapContextInternal
  68
  69
  70 /*!
  71  * KiSwapContext
  72  *
  73  * \brief
  74  *     The KiSwapContext routine switches context to another thread.
  75  *
  76  * BOOLEAN
  77  * KiSwapContext(
  78  *     _In_ KIRQL WaitIrql,
  79  *     _Inout_ PKTHREAD CurrentThread);
  80  *
  81  * \param WaitIrql <r0>
  82  *     ...
  83  *
  84  * \param CurrentThread <r1>
  85  *     Pointer to the KTHREAD of the current thread.
  86  *
  87  * \return
  88  *     The WaitStatus of the Target Thread.
  89  *
  90  * \remarks
  91  *     This is a wrapper around KiSwapContextInternal which will save all the
  92  *     non-volatile registers so that the Internal function can use all of
  93  *     them. It will also save the old current thread and set the new one.
  94  *
  95  *     The calling thread does not return after KiSwapContextInternal until
  96  *     another thread switches to it.
  97  *
  98  *--*/
  99     NESTED_ENTRY KiSwapContext
 100
 101     /* Push non-volatiles and return address on the stack */
 102     stmdb sp!,{r4,r5,r6,r7,r8,r9,r10,r11,lr}
 103     // PROLOG_PUSH {r4,r5,r6,r7,r8,r9,r10,r11,lr}
 104
 105     PROLOG_END KiSwapContext
 106
 107     /* Do the swap with the registers correctly setup */
 108     mov32 r0, 0xFFDFF000 // FIXME: properly load the PCR into r0 (PCR should be in CP15, c3, TPIDRPRW)
 109     ldr r0, [r0, #PcCurrentThread] /* Pointer to the new thread */
 110     bl KiSwapContextInternal
 111
 112     /* Restore non-volatiles and return */
 113     ldmia sp!,{r4,r5,r6,r7,r8,r9,r10,r11,pc}
 114
 115     NESTED_END KiSwapContext
 116
 117
 118
 119     NESTED_ENTRY KiThreadStartup
 120     PROLOG_END KiThreadStartup
 121
 122     /* Lower IRQL to APC_LEVEL */
 123     mov a1, #1
 124     bl KeLowerIrql
 125
 126     /* Set the start address and startup context */
 127     mov a1, r6
 128     mov a2, r5
 129     blx r7
 130
 131     /* The function must not return! */
 132     __assertfail
 133
 134     NESTED_END KiThreadStartup
 135
 136
 137     NESTED_ENTRY KiSwitchThreads
 138     PROLOG_END KiSwitchThreads
 139
 140         // UNIMPLEMENTED!
 141         __debugbreak
 142
 143     NESTED_END KiSwitchThreads
 144
 145     END
 146 /* EOF */