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