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 * $FreeBSD$ 27 */ 28 29/* 30 * Quick and dirty trampoline to get into 64 bit (long) mode and running 31 * with paging enabled so that we enter the kernel at its linked address. 32 */ 33#define MSR_EFER 0xc0000080 34#define EFER_LME 0x00000100 35#define CR4_PAE 0x00000020 36#define CR4_PSE 0x00000010 37#define CR0_PG 0x80000000 38 39/* GRRR. Deal with BTX that links us for a non-zero location */ 40#define VPBASE 0xa000 41#define VTOP(x) ((x) + VPBASE) 42 43 .data 44 45 .p2align 12,0x40 46 47 .globl PT4 48PT4: 49 .space 0x1000 50 .globl PT3 51PT3: 52 .space 0x1000 53 .globl PT2 54PT2: 55 .space 0x1000 56 57gdtdesc: 58 .word gdtend - gdt 59 .long VTOP(gdt) # low 60 .long 0 # high 61 62gdt: 63 .long 0 # null descriptor 64 .long 0 65 .long 0x00000000 # %cs 66 .long 0x00209800 67 .long 0x00000000 # %ds 68 .long 0x00008000 69gdtend: 70 71 .text 72 .code32 73 74 .globl amd64_tramp 75amd64_tramp: 76 /* Be sure that interrupts are disabled */ 77 cli 78 79 /* Turn on EFER.LME */ 80 movl $MSR_EFER, %ecx 81 rdmsr 82 orl $EFER_LME, %eax 83 wrmsr 84 85 /* Turn on PAE */ 86 movl %cr4, %eax 87 orl $CR4_PAE, %eax 88 movl %eax, %cr4 89 90 /* Set %cr3 for PT4 */ 91 movl $VTOP(PT4), %eax 92 movl %eax, %cr3 93 94 /* Turn on paging (implicitly sets EFER.LMA) */ 95 movl %cr0, %eax 96 orl $CR0_PG, %eax 97 movl %eax, %cr0 98 99 /* Now we're in compatibility mode. set %cs for long mode */ 100 movl $VTOP(gdtdesc), %eax 101 movl VTOP(entry_hi), %esi 102 movl VTOP(entry_lo), %edi 103 lgdt (%eax) 104 ljmp $0x8, $VTOP(longmode) 105 106 .code64 107longmode: 108 /* We're still running V=P, jump to entry point */ 109 movl %esi, %eax 110 salq $32, %rax 111 orq %rdi, %rax 112 pushq %rax 113 ret 114