1 ;------------------------------------------------------------------------------ 2 ; 3 ; Copyright (c) 2014, Intel Corporation. All rights reserved.<BR> 4 ; This program and the accompanying materials 5 ; are licensed and made available under the terms and conditions of the BSD License 6 ; which accompanies this distribution. The full text of the license may be found at 7 ; http://opensource.org/licenses/bsd-license.php. 8 ; 9 ; THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS, 10 ; WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED. 11 ; 12 ; Abstract: 13 ; 14 ; Switch the stack from temporary memory to permenent memory. 15 ; 16 ;------------------------------------------------------------------------------ 17 18 .586p 19 .model flat,C 20 .code 21 22 ;------------------------------------------------------------------------------ 23 ; VOID 24 ; EFIAPI 25 ; SecSwitchStack ( 26 ; UINT32 TemporaryMemoryBase, 27 ; UINT32 PermenentMemoryBase 28 ; ); 29 ;------------------------------------------------------------------------------ 30 SecSwitchStack PROC 31 ; 32 ; Save three register: eax, ebx, ecx 33 ; 34 push eax 35 push ebx 36 push ecx 37 push edx 38 39 ; 40 ; !!CAUTION!! this function address's is pushed into stack after 41 ; migration of whole temporary memory, so need save it to permenent 42 ; memory at first! 43 ; 44 45 mov ebx, [esp + 20] ; Save the first parameter 46 mov ecx, [esp + 24] ; Save the second parameter 47 48 ; 49 ; Save this function's return address into permenent memory at first. 50 ; Then, Fixup the esp point to permenent memory 51 ; 52 mov eax, esp 53 sub eax, ebx 54 add eax, ecx 55 mov edx, dword ptr [esp] ; copy pushed register's value to permenent memory 56 mov dword ptr [eax], edx 57 mov edx, dword ptr [esp + 4] 58 mov dword ptr [eax + 4], edx 59 mov edx, dword ptr [esp + 8] 60 mov dword ptr [eax + 8], edx 61 mov edx, dword ptr [esp + 12] 62 mov dword ptr [eax + 12], edx 63 mov edx, dword ptr [esp + 16] ; Update this function's return address into permenent memory 64 mov dword ptr [eax + 16], edx 65 mov esp, eax ; From now, esp is pointed to permenent memory 66 67 ; 68 ; Fixup the ebp point to permenent memory 69 ; 70 mov eax, ebp 71 sub eax, ebx 72 add eax, ecx 73 mov ebp, eax ; From now, ebp is pointed to permenent memory 74 75 pop edx 76 pop ecx 77 pop ebx 78 pop eax 79 ret 80 SecSwitchStack ENDP 81 82 END 83
