1 ;------------------------------------------------------------------------------ 2 ; 3 ; Copyright (c) 2015, 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 permanent memory. 15 ; 16 ;------------------------------------------------------------------------------ 17 18 SECTION .text 19 20 ;------------------------------------------------------------------------------ 21 ; VOID 22 ; EFIAPI 23 ; SecSwitchStack ( 24 ; UINT32 TemporaryMemoryBase, 25 ; UINT32 PermenentMemoryBase 26 ; ); 27 ;------------------------------------------------------------------------------ 28 global ASM_PFX(SecSwitchStack) 29 ASM_PFX(SecSwitchStack): 30 ; 31 ; Save three register: eax, ebx, ecx 32 ; 33 push eax 34 push ebx 35 push ecx 36 push edx 37 38 ; 39 ; !!CAUTION!! this function address's is pushed into stack after 40 ; migration of whole temporary memory, so need save it to permanent 41 ; memory at first! 42 ; 43 44 mov ebx, [esp + 20] ; Save the first parameter 45 mov ecx, [esp + 24] ; Save the second parameter 46 47 ; 48 ; Save this function's return address into permanent memory at first. 49 ; Then, Fixup the esp point to permanent memory 50 ; 51 mov eax, esp 52 sub eax, ebx 53 add eax, ecx 54 mov edx, dword [esp] ; copy pushed register's value to permanent memory 55 mov dword [eax], edx 56 mov edx, dword [esp + 4] 57 mov dword [eax + 4], edx 58 mov edx, dword [esp + 8] 59 mov dword [eax + 8], edx 60 mov edx, dword [esp + 12] 61 mov dword [eax + 12], edx 62 mov edx, dword [esp + 16] ; Update this function's return address into permanent memory 63 mov dword [eax + 16], edx 64 mov esp, eax ; From now, esp is pointed to permanent memory 65 66 ; 67 ; Fixup the ebp point to permenent memory 68 ; 69 mov eax, ebp 70 sub eax, ebx 71 add eax, ecx 72 mov ebp, eax ; From now, ebp is pointed to permanent memory 73 74 pop edx 75 pop ecx 76 pop ebx 77 pop eax 78 ret 79
