1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
|
#------------------------------------------------------------------------------
#
# Copyright (c) 2006 - 2013, 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.
#
#------------------------------------------------------------------------------
ASM_GLOBAL ASM_PFX(JumpToKernel)
#------------------------------------------------------------------------------
# VOID
# EFIAPI
# JumpToKernel (
# VOID *KernelStart, // %rcx
# VOID *KernelBootParams // %rdx
# );
#------------------------------------------------------------------------------
ASM_PFX(JumpToKernel):
// Set up for executing kernel. BP in %esi, entry point on the stack
// (64-bit when the 'ret' will use it as 32-bit, but we're little-endian)
movq %rdx, %rsi
pushq %rcx
// Jump into the compatibility mode CS
pushq $0x10
leaq 1f(%rip), %rax
pushq %rax
.byte 0x48, 0xcb // retfq
1: // Now in compatibility mode
.code32
movl $0x18, %eax
movl %eax, %ds
movl %eax, %es
movl %eax, %fs
movl %eax, %gs
movl %eax, %ss
// Disable paging
movl %cr0, %eax
btcl $31, %eax
movl %eax, %cr0
// Disable long mode in EFER
movl $0x0c0000080, %ecx
rdmsr
btcl $8, %eax
wrmsr
// Disable PAE
movl %cr4, %eax
btcl $5, %eax
movl %eax, %cr4
// Zero registers and 'return' to kernel
xorl %ebp, %ebp
xorl %edi, %edi
xorl %ebx, %ebx
ret
.code64
|
