IntelFspPkg/Library/BaseFspSwitchStackLib/Ia32/Stack.s

   1 #------------------------------------------------------------------------------
   2 #
   3 # Copyright (c) 2014 - 2015, Intel Corporation. All rights reserved.<BR>
   4 # SPDX-License-Identifier: BSD-2-Clause-Patent
   5 #
   6 # Abstract:
   7 #
   8 #   Switch the stack from temporary memory to permenent memory.
   9 #
  10 #------------------------------------------------------------------------------
  11
  12
  13 #------------------------------------------------------------------------------
  14 # UINT32
  15 # EFIAPI
  16 # Pei2LoaderSwitchStack (
  17 #   VOID
  18 #   )
  19 #------------------------------------------------------------------------------
  20 ASM_GLOBAL ASM_PFX(Pei2LoaderSwitchStack)
  21 ASM_PFX(Pei2LoaderSwitchStack):
  22     xorl    %eax, %eax
  23     jmp     ASM_PFX(FspSwitchStack)
  24
  25 #------------------------------------------------------------------------------
  26 # UINT32
  27 # EFIAPI
  28 # Loader2PeiSwitchStack (
  29 #   VOID
  30 #   )
  31 #------------------------------------------------------------------------------
  32 ASM_GLOBAL ASM_PFX(Loader2PeiSwitchStack)
  33 ASM_PFX(Loader2PeiSwitchStack):
  34     jmp     ASM_PFX(FspSwitchStack)
  35
  36 #------------------------------------------------------------------------------
  37 # UINT32
  38 # EFIAPI
  39 # FspSwitchStack (
  40 #   VOID
  41 #   )
  42 #------------------------------------------------------------------------------
  43 ASM_GLOBAL ASM_PFX(FspSwitchStack)
  44 ASM_PFX(FspSwitchStack):
  45     #
  46     #Save current contexts
  47     #
  48     push    %eax
  49     pushf
  50     cli
  51     pusha
  52     sub     $0x08, %esp
  53     sidt    (%esp)
  54
  55     #
  56     # Load new stack
  57     #
  58     push   %esp
  59     call   ASM_PFX(SwapStack)
  60     movl   %eax, %esp
  61
  62     #
  63     # Restore previous contexts
  64     #
  65     lidt    (%esp)
  66     add     $0x08,%esp
  67     popa
  68     popf
  69     add     $0x04,%esp
  70     ret
  71
  72