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f1baef62 | 1 | ;------------------------------------------------------------------------------\r |
2 | ;\r | |
63d7211e | 3 | ; Copyright (c) 2006 - 2008, Intel Corporation\r |
f1baef62 | 4 | ; All rights reserved. This program and the accompanying materials\r |
5 | ; are licensed and made available under the terms and conditions of the BSD License\r | |
6 | ; which accompanies this distribution. The full text of the license may be found at\r | |
7 | ; http://opensource.org/licenses/bsd-license.php\r | |
8 | ;\r | |
9 | ; THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,\r | |
10 | ; WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.\r | |
11 | ;\r | |
12 | ; Module Name:\r | |
13 | ;\r | |
14 | ; DisablePaging64.Asm\r | |
15 | ;\r | |
16 | ; Abstract:\r | |
17 | ;\r | |
18 | ; AsmDisablePaging64 function\r | |
19 | ;\r | |
20 | ; Notes:\r | |
21 | ;\r | |
22 | ;------------------------------------------------------------------------------\r | |
23 | \r | |
24 | .code\r | |
25 | \r | |
26 | ;------------------------------------------------------------------------------\r | |
27 | ; VOID\r | |
28 | ; EFIAPI\r | |
29 | ; InternalX86DisablePaging64 (\r | |
30 | ; IN UINT16 Cs,\r | |
31 | ; IN UINT32 EntryPoint,\r | |
32 | ; IN UINT32 Context1, OPTIONAL\r | |
33 | ; IN UINT32 Context2, OPTIONAL\r | |
34 | ; IN UINT32 NewStack\r | |
35 | ; );\r | |
36 | ;------------------------------------------------------------------------------\r | |
37 | InternalX86DisablePaging64 PROC\r | |
38 | cli\r | |
ce4c0e31 | 39 | lea rsi, @F ; rsi <- The start address of transition code\r |
5a762061 | 40 | mov edi, [rsp + 28h] ; rdi <- New stack\r |
41 | sub edi, 64 ; rdi <- use 64 byte in stack to hold transition code \r | |
42 | mov r10d, edi ; r10 <- The start address of transicition code below 4G\r | |
ce4c0e31 | 43 | lea rax, mTransitionEnd ; rax <- end of transition code\r |
44 | sub rax, rsi ; rax <- The size of transition piece code \r | |
45 | push rcx ; save rcx to stack\r | |
46 | mov rcx, rax ; rcx <- The size of transition piece code\r | |
47 | rep movsb ; copy transition code to (new stack - 64byte) below 4G\r | |
48 | pop rcx ; restore rcx\r | |
49 | \r | |
f1baef62 | 50 | mov esi, r8d\r |
f1baef62 | 51 | mov edi, r9d\r |
52 | mov eax, [rsp + 28h] ; eax <- New Stack\r | |
1a76fbef | 53 | push rcx ; push Cs to stack\r |
54 | push r10\r | |
55 | DB 48h ; prefix to composite "retq" with next "retf"\r | |
56 | retf ; Use far return to load CS register from stack\r | |
ce4c0e31 | 57 | \r |
58 | ; Start of transition code\r | |
f1baef62 | 59 | @@:\r |
60 | mov esp, eax ; set up new stack\r | |
61 | mov rax, cr0\r | |
62 | btr eax, 31\r | |
63 | mov cr0, rax ; disable paging\r | |
63d7211e | 64 | \r |
65 | mov rbx, rdx ; save EntryPoint to rbx, for rdmsr will overwrite rdx\r | |
f1baef62 | 66 | mov ecx, 0c0000080h\r |
67 | rdmsr\r | |
68 | and ah, NOT 1 ; clear LME\r | |
69 | wrmsr\r | |
70 | mov rax, cr4\r | |
71 | and al, NOT (1 SHL 5) ; clear PAE\r | |
72 | mov cr4, rax\r | |
73 | push rdi ; push Context2\r | |
74 | push rsi ; push Context1\r | |
63d7211e | 75 | call rbx ; transfer control to EntryPoint\r |
f1baef62 | 76 | hlt ; no one should get here\r |
77 | InternalX86DisablePaging64 ENDP\r | |
78 | \r | |
ce4c0e31 | 79 | mTransitionEnd LABEL BYTE\r |
80 | \r | |
f1baef62 | 81 | END\r |