1/*-
2 * Copyright (c) 2003  Peter Wemm <peter@FreeBSD.org>
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 *
26 * $FreeBSD: src/sys/boot/i386/libi386/amd64_tramp.S,v 1.2 2003/05/17 00:30:51 peter Exp $
27 */
28
29#include "../bootasm.h"
30
31/*
32 * Quick and dirty trampoline to get into 64 bit (long) mode and running
33 * with paging enabled so that we enter the kernel at its linked address.
34 */
35#define MSR_EFER	0xc0000080
36#define EFER_LME	0x00000100
37#define CR4_PAE		0x00000020
38#define CR4_PSE		0x00000010
39#define CR0_PG		0x80000000
40
41/* GRRR. Deal with BTX that links us for a non-zero location */
42#define VTOP(x)	((x) + MEM_BTX_USR)
43
44	.data
45
46	.p2align 12,0x40
47
48	.globl	PT4
49PT4:
50	.space	0x1000
51	.globl	PT3
52PT3:
53	.space	0x1000
54	.globl	PT2
55PT2:
56	.space	0x1000
57
58gdtdesc:
59	.word	gdtend - gdt
60	.long	VTOP(gdt)		# low
61	.long	0			# high
62
63gdt:
64	.long	0			# null descriptor
65	.long	0
66	.long	0x00000000		# %cs
67	.long	0x00209800
68	.long	0x00000000		# %ds
69	.long	0x00008000
70gdtend:
71
72	.text
73	.code32
74
75	.globl	x86_64_tramp
76x86_64_tramp:
77	/* Be sure that interrupts are disabled */
78	cli
79
80	/* Turn on EFER.LME */
81	movl	$MSR_EFER, %ecx
82	rdmsr
83	orl	$EFER_LME, %eax
84	wrmsr
85
86	/* Turn on PAE */
87	movl	%cr4, %eax
88	orl	$(CR4_PAE | CR4_PSE), %eax
89	movl	%eax, %cr4
90
91	/* Set %cr3 for PT4 */
92	movl	$VTOP(PT4), %eax
93	movl	%eax, %cr3
94
95	/* Turn on paging (implicitly sets EFER.LMA) */
96	movl	%cr0, %eax
97	orl	$CR0_PG, %eax
98	movl	%eax, %cr0
99
100	/* Now we're in compatibility mode. set %cs for long mode */
101	movl	$VTOP(gdtdesc), %eax
102	movl	VTOP(entry_hi), %esi
103	movl	VTOP(entry_lo), %edi
104	lgdt	(%eax)
105	ljmp	$0x8, $VTOP(longmode)
106
107	.code64
108longmode:
109	/* We're still running V=P, jump to entry point */
110	movl	%esi, %eax
111	salq	$32, %rax
112	orq	%rdi, %rax
113	pushq	%rax
114	ret
115