freebsd-skq/sys/boot/i386/libi386/amd64_tramp.S
Roger Pau Monné f5417a03e3 don't set CR4 PSE bit on amd64
Setting PSE together with PAE or in long mode just makes the PSE bit
completely ignored, so don't set it.

Sponsored by: Citrix Systems R&D
Reviewed by: kib
2014-07-23 15:53:29 +00:00

114 lines
2.8 KiB
ArmAsm

/*-
* Copyright (c) 2003 Peter Wemm <peter@FreeBSD.org>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $FreeBSD$
*/
/*
* Quick and dirty trampoline to get into 64 bit (long) mode and running
* with paging enabled so that we enter the kernel at its linked address.
*/
#define MSR_EFER 0xc0000080
#define EFER_LME 0x00000100
#define CR4_PAE 0x00000020
#define CR4_PSE 0x00000010
#define CR0_PG 0x80000000
/* GRRR. Deal with BTX that links us for a non-zero location */
#define VPBASE 0xa000
#define VTOP(x) ((x) + VPBASE)
.data
.p2align 12,0x40
.globl PT4
PT4:
.space 0x1000
.globl PT3
PT3:
.space 0x1000
.globl PT2
PT2:
.space 0x1000
gdtdesc:
.word gdtend - gdt
.long VTOP(gdt) # low
.long 0 # high
gdt:
.long 0 # null descriptor
.long 0
.long 0x00000000 # %cs
.long 0x00209800
.long 0x00000000 # %ds
.long 0x00008000
gdtend:
.text
.code32
.globl amd64_tramp
amd64_tramp:
/* Be sure that interrupts are disabled */
cli
/* Turn on EFER.LME */
movl $MSR_EFER, %ecx
rdmsr
orl $EFER_LME, %eax
wrmsr
/* Turn on PAE */
movl %cr4, %eax
orl $CR4_PAE, %eax
movl %eax, %cr4
/* Set %cr3 for PT4 */
movl $VTOP(PT4), %eax
movl %eax, %cr3
/* Turn on paging (implicitly sets EFER.LMA) */
movl %cr0, %eax
orl $CR0_PG, %eax
movl %eax, %cr0
/* Now we're in compatability mode. set %cs for long mode */
movl $VTOP(gdtdesc), %eax
movl VTOP(entry_hi), %esi
movl VTOP(entry_lo), %edi
lgdt (%eax)
ljmp $0x8, $VTOP(longmode)
.code64
longmode:
/* We're still running V=P, jump to entry point */
movl %esi, %eax
salq $32, %rax
orq %rdi, %rax
pushq %rax
ret