1 ;------------------------------------------------------------------------------ 2 ; @file 3 ; Search for the SEC Core entry point 4 ; 5 ; Copyright (c) 2008 - 2011, Intel Corporation. All rights reserved.<BR> 6 ; This program and the accompanying materials 7 ; are licensed and made available under the terms and conditions of the BSD License 8 ; which accompanies this distribution. The full text of the license may be found at 9 ; http://opensource.org/licenses/bsd-license.php 10 ; 11 ; THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS, 12 ; WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED. 13 ; 14 ;------------------------------------------------------------------------------ 15 16 BITS 32 17 18 %define EFI_FV_FILETYPE_SECURITY_CORE 0x03 19 20 ; 21 ; Modified: EAX, EBX, ECX, EDX 22 ; Preserved: EDI, EBP, ESP 23 ; 24 ; @param[in] EBP Address of Boot Firmware Volume (BFV) 25 ; @param[out] ESI SEC Core Entry Point Address 26 ; 27 Flat32SearchForSecEntryPoint: 28 29 ; 30 ; Initialize EBP and ESI to 0 31 ; 32 xor ebx, ebx 33 mov esi, ebx 34 35 ; 36 ; Pass over the BFV header 37 ; 38 mov eax, ebp 39 mov bx, [ebp + 0x30] 40 add eax, ebx 41 jc secEntryPointWasNotFound 42 43 jmp searchingForFfsFileHeaderLoop 44 45 moveForwardWhileSearchingForFfsFileHeaderLoop: 46 ; 47 ; Make forward progress in the search 48 ; 49 inc eax 50 jc secEntryPointWasNotFound 51 52 searchingForFfsFileHeaderLoop: 53 test eax, eax 54 jz secEntryPointWasNotFound 55 56 ; 57 ; Ensure 8 byte alignment 58 ; 59 add eax, 7 60 jc secEntryPointWasNotFound 61 and al, 0xf8 62 63 ; 64 ; Look to see if there is an FFS file at eax 65 ; 66 mov bl, [eax + 0x17] 67 test bl, 0x20 68 jz moveForwardWhileSearchingForFfsFileHeaderLoop 69 mov ecx, [eax + 0x14] 70 and ecx, 0x00ffffff 71 or ecx, ecx 72 jz moveForwardWhileSearchingForFfsFileHeaderLoop 73 add ecx, eax 74 jz jumpSinceWeFoundTheLastFfsFile 75 jc moveForwardWhileSearchingForFfsFileHeaderLoop 76 jumpSinceWeFoundTheLastFfsFile: 77 78 ; 79 ; There seems to be a valid file at eax 80 ; 81 cmp byte [eax + 0x12], EFI_FV_FILETYPE_SECURITY_CORE ; Check File Type 82 jne readyToTryFfsFileAtEcx 83 84 fileTypeIsSecCore: 85 OneTimeCall GetEntryPointOfFfsFile 86 test eax, eax 87 jnz doneSeachingForSecEntryPoint 88 89 readyToTryFfsFileAtEcx: 90 ; 91 ; Try the next FFS file at ECX 92 ; 93 mov eax, ecx 94 jmp searchingForFfsFileHeaderLoop 95 96 secEntryPointWasNotFound: 97 xor eax, eax 98 99 doneSeachingForSecEntryPoint: 100 mov esi, eax 101 102 test esi, esi 103 jnz secCoreEntryPointWasFound 104 105 secCoreEntryPointWasNotFound: 106 ; 107 ; Hang if the SEC entry point was not found 108 ; 109 debugShowPostCode POSTCODE_SEC_NOT_FOUND 110 jz $ 111 112 secCoreEntryPointWasFound: 113 debugShowPostCode POSTCODE_SEC_FOUND 114 115 OneTimeCallRet Flat32SearchForSecEntryPoint 116 117 %define EFI_SECTION_PE32 0x10 118 %define EFI_SECTION_TE 0x12 119 120 ; 121 ; Input: 122 ; EAX - Start of FFS file 123 ; ECX - End of FFS file 124 ; 125 ; Output: 126 ; EAX - Entry point of PE32 (or 0 if not found) 127 ; 128 ; Modified: 129 ; EBX 130 ; 131 GetEntryPointOfFfsFile: 132 test eax, eax 133 jz getEntryPointOfFfsFileErrorReturn 134 add eax, 0x18 ; EAX = Start of section 135 136 getEntryPointOfFfsFileLoopForSections: 137 cmp eax, ecx 138 jae getEntryPointOfFfsFileErrorReturn 139 140 cmp byte [eax + 3], EFI_SECTION_PE32 141 je getEntryPointOfFfsFileFoundPe32Section 142 143 cmp byte [eax + 3], EFI_SECTION_TE 144 je getEntryPointOfFfsFileFoundTeSection 145 146 ; 147 ; The section type was not PE32 or TE, so move to next section 148 ; 149 mov ebx, dword [eax] 150 and ebx, 0x00ffffff 151 add eax, ebx 152 jc getEntryPointOfFfsFileErrorReturn 153 154 ; 155 ; Ensure that FFS section is 32-bit aligned 156 ; 157 add eax, 3 158 jc getEntryPointOfFfsFileErrorReturn 159 and al, 0xfc 160 jmp getEntryPointOfFfsFileLoopForSections 161 162 getEntryPointOfFfsFileFoundPe32Section: 163 add eax, 4 ; EAX = Start of PE32 image 164 165 cmp word [eax], 'MZ' 166 jne getEntryPointOfFfsFileErrorReturn 167 movzx ebx, word [eax + 0x3c] 168 add ebx, eax 169 170 ; if (Hdr.Pe32->Signature == EFI_IMAGE_NT_SIGNATURE) 171 cmp dword [ebx], `PE\x00\x00` 172 jne getEntryPointOfFfsFileErrorReturn 173 174 ; *EntryPoint = (VOID *)((UINTN)Pe32Data + 175 ; (UINTN)(Hdr.Pe32->OptionalHeader.AddressOfEntryPoint & 0x0ffffffff)); 176 add eax, [ebx + 0x4 + 0x14 + 0x10] 177 jmp getEntryPointOfFfsFileReturn 178 179 getEntryPointOfFfsFileFoundTeSection: 180 add eax, 4 ; EAX = Start of TE image 181 mov ebx, eax 182 183 ; if (Hdr.Te->Signature == EFI_TE_IMAGE_HEADER_SIGNATURE) 184 cmp word [ebx], 'VZ' 185 jne getEntryPointOfFfsFileErrorReturn 186 ; *EntryPoint = (VOID *)((UINTN)Pe32Data + 187 ; (UINTN)(Hdr.Te->AddressOfEntryPoint & 0x0ffffffff) + 188 ; sizeof(EFI_TE_IMAGE_HEADER) - Hdr.Te->StrippedSize); 189 add eax, [ebx + 0x8] 190 add eax, 0x28 191 movzx ebx, word [ebx + 0x6] 192 sub eax, ebx 193 jmp getEntryPointOfFfsFileReturn 194 195 getEntryPointOfFfsFileErrorReturn: 196 mov eax, 0 197 198 getEntryPointOfFfsFileReturn: 199 OneTimeCallRet GetEntryPointOfFfsFile 200 201
