UefiCpuPkg/ResetVector/Vtf0/Ia32/SearchForSecEntry.asm

   1 ;------------------------------------------------------------------------------
   2 ; @file
   3 ; Search for the SEC Core entry point
   4 ;
   5 ; Copyright (c) 2008 - 2009, 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
 119 ;
 120 ; Input:
 121 ;   EAX - Start of FFS file
 122 ;   ECX - End of FFS file
 123 ;
 124 ; Output:
 125 ;   EAX - Entry point of PE32 (or 0 if not found)
 126 ;
 127 ; Modified:
 128 ;   EBX
 129 ;
 130 GetEntryPointOfFfsFile:
 131     test    eax, eax
 132     jz      getEntryPointOfFfsFileErrorReturn
 133     add     eax, 0x18       ; EAX = Start of section
 134
 135 getEntryPointOfFfsFileLoopForSections:
 136     cmp     eax, ecx
 137     jae     getEntryPointOfFfsFileErrorReturn
 138
 139     cmp     byte [eax + 3], EFI_SECTION_PE32
 140     je      getEntryPointOfFfsFileFoundPe32Section
 141
 142     ;
 143     ; The section type was not PE32, so move to next section
 144     ;
 145     mov     ebx, dword [eax]
 146     and     ebx, 0x00ffffff
 147     add     eax, ebx
 148     jc      getEntryPointOfFfsFileErrorReturn
 149
 150     ;
 151     ; Ensure that FFS section is 32-bit aligned
 152     ;
 153     add     eax, 3
 154     jc      getEntryPointOfFfsFileErrorReturn
 155     and     al, 0xfc
 156     jmp     getEntryPointOfFfsFileLoopForSections
 157
 158 getEntryPointOfFfsFileFoundPe32Section:
 159     add     eax, 4       ; EAX = Start of PE32 image
 160
 161     mov     ebx, eax
 162     cmp     word [eax], 'MZ'
 163     jne     thereIsNotAnMzSignature
 164     movzx   ebx, word [eax + 0x3c]
 165     add     ebx, eax
 166 thereIsNotAnMzSignature:
 167
 168     ; if (Hdr.Te->Signature == EFI_TE_IMAGE_HEADER_SIGNATURE)
 169     cmp     word [ebx], 'VZ'
 170     jne     thereIsNoVzSignature
 171     ; *EntryPoint = (VOID *)((UINTN)Pe32Data +
 172     ;   (UINTN)(Hdr.Te->AddressOfEntryPoint & 0x0ffffffff) +
 173     ;   sizeof(EFI_TE_IMAGE_HEADER) - Hdr.Te->StrippedSize);
 174     add     eax, [ebx + 0x8]
 175     add     eax, 0x28
 176     movzx   ebx, word [ebx + 0x6]
 177     sub     eax, ebx
 178     jmp     getEntryPointOfFfsFileReturn
 179
 180 thereIsNoVzSignature:
 181
 182     ; if (Hdr.Pe32->Signature == EFI_IMAGE_NT_SIGNATURE)
 183     cmp     dword [ebx], `PE\x00\x00`
 184     jne     getEntryPointOfFfsFileErrorReturn
 185
 186     ; *EntryPoint = (VOID *)((UINTN)Pe32Data +
 187     ;   (UINTN)(Hdr.Pe32->OptionalHeader.AddressOfEntryPoint & 0x0ffffffff));
 188     add     eax, [ebx + 0x4 + 0x14 + 0x10]
 189     jmp     getEntryPointOfFfsFileReturn
 190
 191 getEntryPointOfFfsFileErrorReturn:
 192     mov     eax, 0
 193
 194 getEntryPointOfFfsFileReturn:
 195     OneTimeCallRet GetEntryPointOfFfsFile
 196