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;------------------------------------------------------------------------------
;
; Copyright (c) 2006 - 2013, Intel Corporation. All rights reserved.<BR>
;
; SPDX-License-Identifier: BSD-2-Clause-Patent
;
;------------------------------------------------------------------------------
DEFAULT REL
SECTION .text
;------------------------------------------------------------------------------
; VOID
; EFIAPI
; JumpToKernel (
; VOID *KernelStart, // rcx
; VOID *KernelBootParams // rdx
; );
;------------------------------------------------------------------------------
global ASM_PFX(JumpToKernel)
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)
mov rsi, rdx
push rcx
; Jump into the compatibility mode CS
push 0x10
lea rax, [.0]
push rax
DB 0x48, 0xcb ; retfq
.0:
; Now in compatibility mode.
DB 0xb8, 0x18, 0x0, 0x0, 0x0 ; movl $0x18, %eax
DB 0x8e, 0xd8 ; movl %eax, %ds
DB 0x8e, 0xc0 ; movl %eax, %es
DB 0x8e, 0xe0 ; movl %eax, %fs
DB 0x8e, 0xe8 ; movl %eax, %gs
DB 0x8e, 0xd0 ; movl %eax, %ss
; Disable paging
DB 0xf, 0x20, 0xc0 ; movl %cr0, %eax
DB 0xf, 0xba, 0xf8, 0x1f ; btcl $31, %eax
DB 0xf, 0x22, 0xc0 ; movl %eax, %cr0
; Disable long mode in EFER
DB 0xb9, 0x80, 0x0, 0x0, 0xc0 ; movl $0x0c0000080, %ecx
DB 0xf, 0x32 ; rdmsr
DB 0xf, 0xba, 0xf8, 0x8 ; btcl $8, %eax
DB 0xf, 0x30 ; wrmsr
; Disable PAE
DB 0xf, 0x20, 0xe0 ; movl %cr4, %eax
DB 0xf, 0xba, 0xf8, 0x5 ; btcl $5, %eax
DB 0xf, 0x22, 0xe0 ; movl %eax, %cr4
DB 0x31, 0xed ; xor %ebp, %ebp
DB 0x31, 0xff ; xor %edi, %edi
DB 0x31, 0xdb ; xor %ebx, %ebx
DB 0xc3 ; ret
;------------------------------------------------------------------------------
; VOID
; EFIAPI
; JumpToUefiKernel (
; EFI_HANDLE ImageHandle, // rcx
; EFI_SYSTEM_TABLE *SystemTable, // rdx
; VOID *KernelBootParams // r8
; VOID *KernelStart, // r9
; );
;------------------------------------------------------------------------------
global ASM_PFX(JumpToUefiKernel)
ASM_PFX(JumpToUefiKernel):
mov rdi, rcx
mov rsi, rdx
mov rdx, r8
xor rax, rax
mov eax, [r8 + 0x264]
add r9, rax
add r9, 0x200
call r9
ret
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