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