1 files changed, 152 insertions, 0 deletions
diff --git a/ArmPkg/Drivers/CpuDxe/ExceptionSupport.asm b/ArmPkg/Drivers/CpuDxe/ExceptionSupport.asm
new file mode 100755
index 0000000000..d91720cff3
--- /dev/null
+++ b/ArmPkg/Drivers/CpuDxe/ExceptionSupport.asm
@@ -0,0 +1,152 @@
+//------------------------------------------------------------------------------ 
+//
+// Copyright (c) 2008-2009 Apple Inc. All rights reserved.
+//
+// All rights reserved. This program and the accompanying materials
+// are licensed and made available under the terms and conditions of the BSD License
+// which accompanies this distribution.  The full text of the license may be found at
+// http://opensource.org/licenses/bsd-license.php
+//
+// THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
+// WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
+//
+//------------------------------------------------------------------------------
+
+  EXPORT  ExceptionHandlersStart
+  EXPORT  ExceptionHandlersEnd
+  EXPORT  CommonExceptionEntry
+  EXPORT  AsmCommonExceptionEntry
+  IMPORT  CommonCExceptionHandler
+
+  PRESERVE8
+  AREA  DxeExceptionHandlers, CODE, READONLY
+  
+ExceptionHandlersStart
+
+Reset
+  b   ResetEntry
+
+UndefinedInstruction
+  b   UndefinedInstructionEntry
+
+SoftwareInterrupt
+  b   SoftwareInterruptEntry
+
+PrefetchAbort
+  b   PrefetchAbortEntry
+
+DataAbort
+  b   DataAbortEntry
+
+ReservedException
+  b   ReservedExceptionEntry
+
+Irq
+  b   IrqEntry
+
+Fiq
+  b   FiqEntry
+
+ResetEntry
+  stmfd     SP!,{R0-R1}
+  mov       R0,#0
+  ldr       R1,CommonExceptionEntry
+  bx        R1
+
+UndefinedInstructionEntry
+  stmfd     SP!,{R0-R1}
+  mov       R0,#1
+  ldr       R1,CommonExceptionEntry
+  bx        R1
+
+SoftwareInterruptEntry
+  stmfd     SP!,{R0-R1}
+  mov       R0,#2
+  ldr       R1,CommonExceptionEntry
+  bx        R1
+
+PrefetchAbortEntry
+  stmfd     SP!,{R0-R1}
+  mov       R0,#3
+  SUB       LR,LR,#4
+  ldr       R1,CommonExceptionEntry
+  bx        R1
+
+DataAbortEntry
+  stmfd     SP!,{R0-R1}
+  mov       R0,#4
+  SUB       LR,LR,#8
+  ldr       R1,CommonExceptionEntry
+  bx        R1
+
+ReservedExceptionEntry
+  stmfd     SP!,{R0-R1}
+  mov       R0,#5
+  ldr       R1,CommonExceptionEntry
+  bx        R1
+
+IrqEntry
+  stmfd     SP!,{R0-R1}
+  mov       R0,#6
+  SUB       LR,LR,#4
+  ldr       R1,CommonExceptionEntry
+  bx        R1
+
+FiqEntry
+  stmfd     SP!,{R0-R1}
+  mov       R0,#7
+  SUB       LR,LR,#4
+  ldr       R1,CommonExceptionEntry
+  bx        R1
+
+CommonExceptionEntry
+  dcd       0x12345678
+
+ExceptionHandlersEnd
+
+AsmCommonExceptionEntry
+  mrc       p15, 0, r1, c6, c0, 2   ; Read IFAR
+  stmfd     SP!,{R1}                ; Store the IFAR
+  
+  mrc       p15, 0, r1, c5, c0, 1   ; Read IFSR
+  stmfd     SP!,{R1}                ; Store the IFSR
+  
+  mrc       p15, 0, r1, c6, c0, 0   ; Read DFAR
+  stmfd     SP!,{R1}                ; Store the DFAR
+  
+  mrc       p15, 0, r1, c5, c0, 0   ; Read DFSR
+  stmfd     SP!,{R1}                ; Store the DFSR
+  
+  mrs       R1,SPSR                 ; Read SPSR (which is the pre-exception CPSR)
+  stmfd     SP!,{R1}                ; Store the SPSR
+  
+  stmfd     SP!,{LR}                ; Store the link register (which is the pre-exception PC)
+  stmfd     SP,{SP,LR}^             ; Store user/system mode stack pointer and link register
+  nop                               ; Required by ARM architecture
+  SUB       SP,SP,#0x08             ; Adjust stack pointer
+  stmfd     SP!,{R2-R12}            ; Store general purpose registers
+  
+  ldr       R3,[SP,#0x50]           ; Read saved R1 from the stack (it was saved by the exception entry routine)
+  ldr       R2,[SP,#0x4C]           ; Read saved R0 from the stack (it was saved by the exception entry routine)
+  stmfd     SP!,{R2-R3}             ; Store general purpose registers R0 and R1
+  
+  mov       R1,SP                   ; Prepare System Context pointer as an argument for the exception handler
+  
+  sub       SP,SP,#4                ; Adjust SP to preserve 8-byte alignment
+  blx       CommonCExceptionHandler ; Call exception handler
+  add       SP,SP,#4                ; Adjust SP back to where we were
+  
+  ldr       R2,[SP,#0x40]           ; Load CPSR from context, in case it has changed
+  MSR       SPSR_cxsf,R2            ; Store it back to the SPSR to be restored when exiting this handler
+
+  ldmfd     SP!,{R0-R12}            ; Restore general purpose registers
+  ldm       SP,{SP,LR}^             ; Restore user/system mode stack pointer and link register
+  nop                               ; Required by ARM architecture
+  add       SP,SP,#0x08             ; Adjust stack pointer
+  ldmfd     SP!,{LR}                ; Restore the link register (which is the pre-exception PC)
+  add       SP,SP,#0x1C             ; Clear out the remaining stack space
+  movs      PC,LR                   ; Return from exception
+  
+  END
+
+