1/* ----------------------------------------------------------------------- *
 2 *
 3 *   Copyright (C) 1991, 1992 Linus Torvalds
 4 *   Copyright 2007 rPath, Inc. - All Rights Reserved
 5 *
 6 *   This file is part of the Linux kernel, and is made available under
 7 *   the terms of the GNU General Public License version 2.
 8 *
 9 * ----------------------------------------------------------------------- */
10
11/*
12 * The actual transition into protected mode
13 */
14
15#include <asm/boot.h>
16#include <asm/processor-flags.h>
17#include <asm/segment.h>
18#include <linux/linkage.h>
19
20	.text
21	.code16
22
23/*
24 * void protected_mode_jump(u32 entrypoint, u32 bootparams);
25 */
26GLOBAL(protected_mode_jump)
27	movl	%edx, %esi		# Pointer to boot_params table
28
29	xorl	%ebx, %ebx
30	movw	%cs, %bx
31	shll	$4, %ebx
32	addl	%ebx, 2f
33	jmp	1f			# Short jump to serialize on 386/486
341:
35
36	movw	$__BOOT_DS, %cx
37	movw	$__BOOT_TSS, %di
38
39	movl	%cr0, %edx
40	orb	$X86_CR0_PE, %dl	# Protected mode
41	movl	%edx, %cr0
42
43	# Transition to 32-bit mode
44	.byte	0x66, 0xea		# ljmpl opcode
452:	.long	in_pm32			# offset
46	.word	__BOOT_CS		# segment
47ENDPROC(protected_mode_jump)
48
49	.code32
50	.section ".text32","ax"
51GLOBAL(in_pm32)
52	# Set up data segments for flat 32-bit mode
53	movl	%ecx, %ds
54	movl	%ecx, %es
55	movl	%ecx, %fs
56	movl	%ecx, %gs
57	movl	%ecx, %ss
58	# The 32-bit code sets up its own stack, but this way we do have
59	# a valid stack if some debugging hack wants to use it.
60	addl	%ebx, %esp
61
62	# Set up TR to make Intel VT happy
63	ltr	%di
64
65	# Clear registers to allow for future extensions to the
66	# 32-bit boot protocol
67	xorl	%ecx, %ecx
68	xorl	%edx, %edx
69	xorl	%ebx, %ebx
70	xorl	%ebp, %ebp
71	xorl	%edi, %edi
72
73	# Set up LDTR to make Intel VT happy
74	lldt	%cx
75
76	jmpl	*%eax			# Jump to the 32-bit entrypoint
77ENDPROC(in_pm32)

 1/* SPDX-License-Identifier: GPL-2.0-only */
 2/* ----------------------------------------------------------------------- *
 3 *
 4 *   Copyright (C) 1991, 1992 Linus Torvalds
 5 *   Copyright 2007 rPath, Inc. - All Rights Reserved
 6 *
 
 
 
 7 * ----------------------------------------------------------------------- */
 8
 9/*
10 * The actual transition into protected mode
11 */
12
13#include <asm/boot.h>
14#include <asm/processor-flags.h>
15#include <asm/segment.h>
16#include <linux/linkage.h>
17
18	.text
19	.code16
20
21/*
22 * void protected_mode_jump(u32 entrypoint, u32 bootparams);
23 */
24SYM_FUNC_START_NOALIGN(protected_mode_jump)
25	movl	%edx, %esi		# Pointer to boot_params table
26
27	xorl	%ebx, %ebx
28	movw	%cs, %bx
29	shll	$4, %ebx
30	addl	%ebx, 2f
31	jmp	1f			# Short jump to serialize on 386/486
321:
33
34	movw	$__BOOT_DS, %cx
35	movw	$__BOOT_TSS, %di
36
37	movl	%cr0, %edx
38	orb	$X86_CR0_PE, %dl	# Protected mode
39	movl	%edx, %cr0
40
41	# Transition to 32-bit mode
42	.byte	0x66, 0xea		# ljmpl opcode
432:	.long	.Lin_pm32		# offset
44	.word	__BOOT_CS		# segment
45SYM_FUNC_END(protected_mode_jump)
46
47	.code32
48	.section ".text32","ax"
49SYM_FUNC_START_LOCAL_NOALIGN(.Lin_pm32)
50	# Set up data segments for flat 32-bit mode
51	movl	%ecx, %ds
52	movl	%ecx, %es
53	movl	%ecx, %fs
54	movl	%ecx, %gs
55	movl	%ecx, %ss
56	# The 32-bit code sets up its own stack, but this way we do have
57	# a valid stack if some debugging hack wants to use it.
58	addl	%ebx, %esp
59
60	# Set up TR to make Intel VT happy
61	ltr	%di
62
63	# Clear registers to allow for future extensions to the
64	# 32-bit boot protocol
65	xorl	%ecx, %ecx
66	xorl	%edx, %edx
67	xorl	%ebx, %ebx
68	xorl	%ebp, %ebp
69	xorl	%edi, %edi
70
71	# Set up LDTR to make Intel VT happy
72	lldt	%cx
73
74	jmpl	*%eax			# Jump to the 32-bit entrypoint
75SYM_FUNC_END(.Lin_pm32)