1;------------------------------------------------------------------------------
2;
3; Copyright (c) 2010 - 2012, 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; Module Name:
13;
14;   PageFaultHandler.asm
15;
16; Abstract:
17;
18;   Defines page fault handler used to hook SMM IDT
19;
20;------------------------------------------------------------------------------
21
22EXTERN mOriginalHandler:QWORD
23EXTERN PageFaultHandler:PROC
24
25  .code
26
27PageFaultHandlerHook PROC
28    push    rax                         ; save all volatile registers
29    push    rcx
30    push    rdx
31    push    r8
32    push    r9
33    push    r10
34    push    r11
35
36    add     rsp, -10h * 6 - 8          ; reserve memory to store XMM registers and make address 16-byte alignment
37    movdqa  [rsp], xmm0
38    movdqa  [rsp + 10h], xmm1
39    movdqa  [rsp + 20h], xmm2
40    movdqa  [rsp + 30h], xmm3
41    movdqa  [rsp + 40h], xmm4
42    movdqa  [rsp + 50h], xmm5
43
44    add     rsp, -20h
45    call    PageFaultHandler
46    add     rsp, 20h
47
48    movdqa  xmm0, [rsp]
49    movdqa  xmm1, [rsp + 10h] 
50    movdqa  xmm2, [rsp + 20h]
51    movdqa  xmm3, [rsp + 30h]
52    movdqa  xmm4, [rsp + 40h]
53    movdqa  xmm5, [rsp + 50h]
54    add     rsp, 10h * 6 + 8
55    
56    test    al, al                      ; set ZF flag
57    pop     r11
58    pop     r10
59    pop     r9
60    pop     r8
61    pop     rdx
62    pop     rcx
63    pop     rax                         ; restore all volatile registers
64    jnz     @F                          ; check ZF flag
65    jmp     mOriginalHandler
66@@:
67    add     rsp, 08h                    ; skip error code for PF
68    iretq
69PageFaultHandlerHook ENDP
70  END
71