1 files changed, 86 insertions, 0 deletions
diff --git a/Core/UefiCpuPkg/ResetVector/Vtf0/Ia32/SearchForBfvBase.asm b/Core/UefiCpuPkg/ResetVector/Vtf0/Ia32/SearchForBfvBase.asm
new file mode 100644
index 0000000000..d0c2d8c39c
--- /dev/null
+++ b/Core/UefiCpuPkg/ResetVector/Vtf0/Ia32/SearchForBfvBase.asm
@@ -0,0 +1,86 @@
+;------------------------------------------------------------------------------
+; @file
+; Search for the Boot Firmware Volume (BFV) base address
+;
+; Copyright (c) 2008 - 2009, Intel Corporation. All rights reserved.<BR>
+; This program and the accompanying materials
+; are licensed and made available under the terms and conditions of the BSD License
+; which accompanies this distribution.  The full text of the license may be found at
+; http://opensource.org/licenses/bsd-license.php
+;
+; THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
+; WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
+;
+;------------------------------------------------------------------------------
+
+;#define EFI_FIRMWARE_FILE_SYSTEM2_GUID \
+;  { 0x8c8ce578, 0x8a3d, 0x4f1c, { 0x99, 0x35, 0x89, 0x61, 0x85, 0xc3, 0x2d, 0xd3 } }
+%define FFS_GUID_DWORD0 0x8c8ce578
+%define FFS_GUID_DWORD1 0x4f1c8a3d
+%define FFS_GUID_DWORD2 0x61893599
+%define FFS_GUID_DWORD3 0xd32dc385
+
+BITS    32
+
+;
+; Modified:  EAX, EBX
+; Preserved: EDI, ESP
+;
+; @param[out]  EBP  Address of Boot Firmware Volume (BFV)
+;
+Flat32SearchForBfvBase:
+
+    xor     eax, eax
+searchingForBfvHeaderLoop:
+    ;
+    ; We check for a firmware volume at every 4KB address in the top 16MB
+    ; just below 4GB.  (Addresses at 0xffHHH000 where H is any hex digit.)
+    ;
+    sub     eax, 0x1000
+    cmp     eax, 0xff000000
+    jb      searchedForBfvHeaderButNotFound
+
+    ;
+    ; Check FFS GUID
+    ;
+    cmp     dword [eax + 0x10], FFS_GUID_DWORD0
+    jne     searchingForBfvHeaderLoop
+    cmp     dword [eax + 0x14], FFS_GUID_DWORD1
+    jne     searchingForBfvHeaderLoop
+    cmp     dword [eax + 0x18], FFS_GUID_DWORD2
+    jne     searchingForBfvHeaderLoop
+    cmp     dword [eax + 0x1c], FFS_GUID_DWORD3
+    jne     searchingForBfvHeaderLoop
+
+    ;
+    ; Check FV Length
+    ;
+    cmp     dword [eax + 0x24], 0
+    jne     searchingForBfvHeaderLoop
+    mov     ebx, eax
+    add     ebx, dword [eax + 0x20]
+    jnz     searchingForBfvHeaderLoop
+
+    jmp     searchedForBfvHeaderAndItWasFound
+
+searchedForBfvHeaderButNotFound:
+    ;
+    ; Hang if the SEC entry point was not found
+    ;
+    debugShowPostCode POSTCODE_BFV_NOT_FOUND
+
+    ;
+    ; 0xbfbfbfbf in the EAX & EBP registers helps signal what failed
+    ; for debugging purposes.
+    ;
+    mov     eax, 0xBFBFBFBF
+    mov     ebp, eax
+    jmp     $
+
+searchedForBfvHeaderAndItWasFound:
+    mov     ebp, eax
+
+    debugShowPostCode POSTCODE_BFV_FOUND
+
+    OneTimeCallRet Flat32SearchForBfvBase
+