- We now implement a skeleton framework for context switching

- The only things we do are swap the stack and then display the old/new thread/stack.
- More work to be done to actually save the non-volatiles, prepare the thread state, and restore the volatiles for the new thread.
- Then we will return to the saved return address, and we should be in Phase 1 with working thread switching/scheduling.

svn path=/trunk/; revision=33935

reactos/ntoskrnl/include/internal/arm/ksarm.h

@@ -55,6 +55,11 @@
  */
 .equ PcCurrentIrql,        0x14C
 
+/*
+ * KTHREAD Offsets
+ */
+.equ ThKernelStack,        0x20
+
 #else
 
 /*

reactos/ntoskrnl/ke/arm/ctxswtch.s

@@ -0,0 +1,50 @@
+/*
+ * PROJECT:         ReactOS Kernel
+ * LICENSE:         GPL - See COPYING in the top level directory
+ * FILE:            ntoskrnl/ke/arm/ctxswtch.s
+ * PURPOSE:         Context Switch and Idle Thread on ARM
+ * PROGRAMMERS:     ReactOS Portable Systems Group
+ */
+
+    .title "ARM Context Switching"
+    .include "ntoskrnl/include/internal/arm/kxarm.h"
+    .include "ntoskrnl/include/internal/arm/ksarm.h"
+
+    TEXTAREA
+    NESTED_ENTRY KiSwapContext
+    PROLOG_END KiSwapContext
+    //
+    // a1 = Old Thread
+    // a2 = New Thread
+    //
+    
+    //
+    // Save volatile registers for the OLD thread
+    //
+    
+    //
+    // Switch stacks
+    //
+    str sp, [a1, #ThKernelStack]
+    ldr sp, [a2, #ThKernelStack]
+    
+    //
+    // Call the C context switch code
+    //
+    bl KiSwapContextInternal
+    
+    //
+    // Restore volatile registers for the NEW thread
+    //
+    
+    //
+    // Jump to saved restore address
+    //
+    
+    //
+    // FIXME: TODO
+    //
+    b .
+    
+    ENTRY_END KiSwapContext
+

reactos/ntoskrnl/ke/arm/stubs.c

@@ -2,6 +2,8 @@
 #define NDEBUG
 #include "debug.h"
 
+CCHAR KeNumberProcessors;
+ULONG KeDcacheFlushCount;
 ULONG KeActiveProcessors;
 ULONG KeProcessorArchitecture;
 ULONG KeProcessorLevel;

reactos/ntoskrnl/ke/arm/stubs_asm.s

@@ -12,17 +12,14 @@ GENERATE_ARM_STUB _local_unwind2
 //
 // Exported Ke Arch-Specific APIs
 //
-GENERATE_ARM_STUB KiSwapContext
 GENERATE_ARM_STUB DbgBreakPointWithStatus 
 GENERATE_ARM_STUB KeConnectInterrupt 
-GENERATE_ARM_STUB KeDcacheFlushCount 
 GENERATE_ARM_STUB KeDisconnectInterrupt 
 GENERATE_ARM_STUB KeFlushEntireTb 
 GENERATE_ARM_STUB KeGetRecommendedSharedDataAlignment 
 GENERATE_ARM_STUB KeIcacheFlushCount 
 GENERATE_ARM_STUB KeInitializeInterrupt 
 GENERATE_ARM_STUB KeInvalidateAllCaches
-GENERATE_ARM_STUB KeNumberProcessors 
 GENERATE_ARM_STUB KeQueryActiveProcessors 
 GENERATE_ARM_STUB KeRaiseUserException 
 GENERATE_ARM_STUB KeSaveStateForHibernate 

reactos/ntoskrnl/ke/arm/trapc.c

@@ -24,7 +24,6 @@ KiSystemCall(
     IN PULONG Arguments,
     IN ULONG ArgumentCount
 );
- 
 
 /* FUNCTIONS ******************************************************************/
 
@@ -34,6 +33,18 @@ HalGetInterruptSource(VOID);
 VOID FASTCALL
 HalClearSoftwareInterrupt(IN KIRQL Request);
 
+VOID
+KiSwapContextInternal(IN PKTHREAD OldThread,
+                      IN PKTHREAD NewThread)
+{
+    //
+    // FIXME: TODO
+    //
+    DPRINT1("Switching from: %p to %p\n", OldThread, NewThread);
+    DPRINT1("Stacks: %p %p\n", OldThread->KernelStack, NewThread->KernelStack);
+    while (TRUE);
+}
+
 VOID
 KiDispatchInterrupt(VOID)
 {
@@ -107,9 +118,12 @@ KiDispatchInterrupt(VOID)
         
         //
         // Swap to the new thread
+        // On ARM we call KiSwapContext instead of KiSwapContextInternal,
+        // because we're calling this from C code and not assembly.
+        // This is similar to how it gets called for unwaiting, on x86
         //
         DPRINT1("Swapping context!\n");
-        //KiSwapContextInternal();
+        KiSwapContext(OldThread, NewThread);
         while (TRUE);
     }
 }

reactos/ntoskrnl/ntoskrnl-generic.rbuild

@@ -63,6 +63,7 @@
 				<file first="true">boot.s</file>
 				<file>arm_kprintf.c</file>
 				<file>cpu.c</file>
+				<file>ctxswtch.s</file>
 				<file>exp.c</file>
 				<file>kiinit.c</file>
 				<file>stubs_asm.s</file>