1;------------------------------------------------------------------------------
2;
3; Copyright (c) 2006 - 2013, Intel Corporation. All rights reserved.<BR>
4;
5; This program and the accompanying materials
6; are licensed and made available under the terms and conditions of the BSD License
7; which accompanies this distribution.  The full text of the license may be found at
8; http://opensource.org/licenses/bsd-license.php.
9;
10; THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
11; WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
12;
13;------------------------------------------------------------------------------
14
15  DEFAULT REL
16  SECTION .text
17
18;------------------------------------------------------------------------------
19; VOID
20; EFIAPI
21; JumpToKernel (
22;   VOID *KernelStart,         // rcx
23;   VOID *KernelBootParams     // rdx
24;   );
25;------------------------------------------------------------------------------
26global ASM_PFX(JumpToKernel)
27ASM_PFX(JumpToKernel):
28
29    ; Set up for executing kernel. BP in %esi, entry point on the stack
30    ; (64-bit when the 'ret' will use it as 32-bit, but we're little-endian)
31    mov    rsi, rdx
32    push   rcx
33
34    ; Jump into the compatibility mode CS
35    push    0x10
36    lea     rax, [.0]
37    push    rax
38    DB 0x48, 0xcb                      ; retfq
39
40.0:
41    ; Now in compatibility mode.
42
43    DB 0xb8, 0x18, 0x0, 0x0, 0x0    ; movl    $0x18, %eax
44    DB 0x8e, 0xd8                      ; movl    %eax, %ds
45    DB 0x8e, 0xc0                      ; movl    %eax, %es
46    DB 0x8e, 0xe0                      ; movl    %eax, %fs
47    DB 0x8e, 0xe8                      ; movl    %eax, %gs
48    DB 0x8e, 0xd0                      ; movl    %eax, %ss
49
50    ; Disable paging
51    DB 0xf, 0x20, 0xc0                ; movl    %cr0, %eax
52    DB 0xf, 0xba, 0xf8, 0x1f          ; btcl    $31, %eax
53    DB 0xf, 0x22, 0xc0                ; movl    %eax, %cr0
54
55    ; Disable long mode in EFER
56    DB 0xb9, 0x80, 0x0, 0x0, 0xc0    ; movl    $0x0c0000080, %ecx
57    DB 0xf, 0x32                      ; rdmsr
58    DB 0xf, 0xba, 0xf8, 0x8          ; btcl    $8, %eax
59    DB 0xf, 0x30                      ; wrmsr
60
61    ; Disable PAE
62    DB 0xf, 0x20, 0xe0                ; movl    %cr4, %eax
63    DB 0xf, 0xba, 0xf8, 0x5          ; btcl    $5, %eax
64    DB 0xf, 0x22, 0xe0                ; movl    %eax, %cr4
65
66    DB 0x31, 0xed                      ; xor     %ebp, %ebp
67    DB 0x31, 0xff                      ; xor     %edi, %edi
68    DB 0x31, 0xdb                      ; xor     %ebx, %ebx
69    DB 0xc3                            ; ret
70
71;------------------------------------------------------------------------------
72; VOID
73; EFIAPI
74; JumpToUefiKernel (
75;   EFI_HANDLE ImageHandle,        // rcx
76;   EFI_SYSTEM_TABLE *SystemTable, // rdx
77;   VOID *KernelBootParams         // r8
78;   VOID *KernelStart,             // r9
79;   );
80;------------------------------------------------------------------------------
81global ASM_PFX(JumpToUefiKernel)
82ASM_PFX(JumpToUefiKernel):
83
84    mov     rdi, rcx
85    mov     rsi, rdx
86    mov     rdx, r8
87    xor     rax, rax
88    mov     eax, [r8 + 0x264]
89    add     r9, rax
90    add     r9, 0x200
91    call    r9
92    ret
93
94