UnixPkg/Sec/Ia32/Stack.S

   1 #------------------------------------------------------------------------------
   2 #
   3 # Copyright (c) 2008 - 2009, Intel Corporation
   4 # Portions copyright (c) 2008-2009 Apple Inc.
   5 # All rights reserved. This program and the accompanying materials
   6 # are licensed and made available under the terms and conditions of the BSD License
   7 # which accompanies this distribution.  The full text of the license may be found at
   8 # http://opensource.org/licenses/bsd-license.php
   9 #
  10 # THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  11 # WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  12 #
  13 # Module Name:
  14 #
  15 #   Stack.asm
  16 #
  17 # Abstract:
  18 #
  19 #   Switch the stack from temporary memory to permenent memory.
  20 #
  21 #------------------------------------------------------------------------------
  22
  23 #------------------------------------------------------------------------------
  24 # VOID
  25 # EFIAPI
  26 # SecSwitchStack (
  27 #   UINT32   TemporaryMemoryBase,
  28 #   UINT32   PermenentMemoryBase
  29 #   );
  30 #------------------------------------------------------------------------------
  31
  32 #include <ProcessorBind.h>
  33
  34 ASM_GLOBAL ASM_PFX(SecSwitchStack)
  35 ASM_PFX(SecSwitchStack):
  36 #
  37 # Save three register: eax, ebx, ecx
  38 #
  39     push  %eax
  40     push  %ebx
  41     push  %ecx
  42     push  %edx
  43
  44 #
  45 # !!CAUTION!! this function address's is pushed into stack after
  46 # migration of whole temporary memory, so need save it to permenent
  47 # memory at first!
  48 #
  49
  50     movl  20(%esp), %ebx            # Save the first parameter
  51     movl  24(%esp), %ecx            # Save the second parameter
  52
  53 #
  54 # Save this function's return address into permenent memory at first.
  55 # Then, Fixup the esp point to permenent memory
  56 #
  57
  58     movl  %esp, %eax
  59     subl  %ebx, %eax
  60     addl  %ecx, %eax
  61     movl  (%esp), %edx                 # copy pushed register's value to permenent memory
  62     movl  %edx, (%eax)
  63     movl  4(%esp), %edx
  64     movl  %edx, 4(%eax)
  65     movl  8(%esp), %edx
  66     movl  %edx, 8(%eax)
  67     movl  12(%esp), %edx
  68     movl  %edx, 12(%eax)
  69     movl  16(%esp), %edx
  70     movl  %edx, 16(%eax)
  71     movl  %eax, %esp                   # From now, esp is pointed to permenent memory
  72
  73 #
  74 # Fixup the ebp point to permenent memory
  75 #
  76 #ifndef __APPLE__
  77     movl   %ebp, %eax
  78     subl   %ebx, %eax
  79     addl   %ecx, %eax
  80     movl   %eax, %ebp                  # From now, ebp is pointed to permenent memory
  81
  82 #
  83 # Fixup callee's ebp point for PeiDispatch
  84 #
  85     movl   (%ebp), %eax
  86     subl   %ebx, %eax
  87     addl   %ecx, %eax
  88     movl   %eax, (%ebp)                # From now, Temporary's PPI caller's stack is in permenent memory
  89 #endif
  90
  91     pop   %edx
  92     pop   %ecx
  93     pop   %ebx
  94     pop   %eax
  95     ret