OVMF SEC: Modify to search sections of FFS file for PE32 image.

Previously the code would expect that the PE32 image was in the
first section of the FFS file.  This might not be the case if the
PE32 section is forced to be aligned.

git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@9331 6f19259b-4bc3-4df7-8a09-765794883524

OvmfPkg/ResetVector/Ia32/SearchForSecAndPeiEntries.asm

@@ -144,6 +144,7 @@ peiCoreEntryPointWasFound:
 ;
 ; Input:
 ;   EAX - Start of FFS file
+;   ECX - End of FFS file
 ;
 ; Output:
 ;   EAX - Entry point of PE32 (or 0 if not found)
@@ -154,11 +155,33 @@ peiCoreEntryPointWasFound:
 GetEntryPointOfFfsFileReturnEdx:
     test    eax, eax
     jz      getEntryPointOfFfsFileErrorReturn
+    add     eax, 0x18       ; EAX = Start of section
 
-    cmp     byte [eax + 0x1b], EFI_SECTION_PE32
-    jne     getEntryPointOfFfsFileErrorReturn
+getEntryPointOfFfsFileLoopForSections:
+    cmp     eax, ecx
+    jae     getEntryPointOfFfsFileErrorReturn
 
-    add     eax, 0x1c       ; EAX = Start of PE32 image
+    cmp     byte [eax + 3], EFI_SECTION_PE32
+    je      getEntryPointOfFfsFileFoundPe32Section
+
+    ;
+    ; The section type was not PE32, so move to next section
+    ;
+    mov     ebx, dword [eax]
+    and     ebx, 0x00ffffff
+    add     eax, ebx
+    jc      getEntryPointOfFfsFileErrorReturn
+
+    ;
+    ; Ensure that FFS section is 32-bit aligned
+    ;
+    add     eax, 3
+    jc      getEntryPointOfFfsFileErrorReturn
+    and     al, 0xfc
+    jmp     getEntryPointOfFfsFileLoopForSections
+
+getEntryPointOfFfsFileFoundPe32Section:
+    add     eax, 4       ; EAX = Start of PE32 image
 
     mov     ebx, eax
     cmp     word [eax], 'MZ'