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#
# Copyright (C) 2005 Ondrej Palkovsky
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions
# are met:
#
# - Redistributions of source code must retain the above copyright
#   notice, this list of conditions and the following disclaimer.
# - 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.
# - The name of the author may not be used to endorse or promote products
#   derived from this software without specific prior written permission.
#
# THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 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.
#

#define __ASM__

#include <arch/mm/page.h>   
#include <arch/mm/ptl.h>
#include <arch/pm.h>
#include <arch/cpu.h>
#include <arch/cpuid.h>
#include <arch/boot/boot.h>

#define START_STACK_64  0xffffffff80007c00
                    
#
# This is where we require any SPARTAN-kernel-compatible boot loader
# to pass control in real mode.
#
# Protected mode tables are statically initialised during compile
# time. So we can just load the respective table registers and
# switch to protected mode.
#

#define START_STACK (BOOTSTRAP_OFFSET-0x400)
    
.section K_TEXT_START
.code16
.global kernel_image_start
kernel_image_start:
    cli
    xorw %ax,%ax
    movw %ax,%ds
    movw %ax,%es
    movw %ax,%ss            # initialize stack segment register
    movl $(START_STACK), %esp   # initialize stack pointer
    
    call memmap_arch_init
    
    movl $0x80000000, %eax  
    cpuid
    cmp $0x80000000, %eax   # any function > 80000000h?
    jbe no_long_mode
    movl $(AMD_CPUID_EXTENDED), %eax # Extended function code 80000001
    cpuid
    bt $29, %edx        # Test if long mode is supported.
    jnc no_long_mode

    # Load gdtr, idtr
    lgdt real_bootstrap_gdtr_boot
    
    movl %cr0,%eax
    orl $0x1,%eax
    movl %eax,%cr0          # switch to protected mode

    jmpl $gdtselector(KTEXT32_DES), $now_in_prot

no_long_mode:
1:
    jmp 1b

# Protected 32-bit. We want to reuse the code-seg descriptor,
# the Default operand size must not be 1 when entering long mode
.code32
now_in_prot:  
    # Set up stack & data descriptors
    movw $gdtselector(KDATA_DES), %ax
    movw %ax, %ds
    movw %ax, %ss

    movb $0xd1, %al     # enable A20 using the keyboard controller
    outb %al, $0x64
    movb $0xdf, %al
    outb %al, $0x60

    
    # Enable 64-bit page transaltion entries - CR4.PAE = 1.
    # Paging is not enabled until after long mode is enabled
    movl %cr4, %eax
    btsl $5, %eax
    movl %eax, %cr4

    # Set up paging tables
    leal ptl_0, %eax
    movl %eax, %cr3
    
    # Enable long mode
    movl $EFER_MSR_NUM, %ecx   # EFER MSR number
    rdmsr                   # Read EFER
    btsl $AMD_LME_FLAG, %eax            # Set LME=1
    wrmsr                   # Write EFER
    
    # Enable paging to activate long mode (set CR0.PG=1)
    movl %cr0, %eax
    btsl $31, %eax
    movl %eax, %cr0
    
    # At this point we are in compatibility mode
    jmpl $gdtselector(KTEXT_DES), $start64

.code64
start64:
    movq $(PA2KA(START_STACK)), %rsp

    # Copy kernel to higher physical memory
    movq $BOOTSTRAP_OFFSET, %rsi
    movq $BOOTSTRAP_OFFSET + BOOT_OFFSET, %rdi
    movq $_hardcoded_kernel_size, %rcx
    cld
    rep movsb
    
    call main_bsp   # never returns
1:
    jmp 1b
                
.section K_DATA_START
.align 4096

# Identical mapping of first 16MB and the same of -2GB -> 0 
.global ptl_2
ptl_2:  
    .quad 0x0 | (PTL_WRITABLE | PTL_PRESENT | PTL_2MB_PAGE)
    .quad 0x200000 | (PTL_WRITABLE | PTL_PRESENT | PTL_2MB_PAGE)
    .quad 0x400000 | (PTL_WRITABLE | PTL_PRESENT | PTL_2MB_PAGE)
    .quad 0x600000 | (PTL_WRITABLE | PTL_PRESENT | PTL_2MB_PAGE)
    .quad 0x800000 | (PTL_WRITABLE | PTL_PRESENT | PTL_2MB_PAGE)
    .quad 0xa00000 | (PTL_WRITABLE | PTL_PRESENT | PTL_2MB_PAGE)
    .quad 0xc00000 | (PTL_WRITABLE | PTL_PRESENT | PTL_2MB_PAGE)
    .quad 0xe00000 | (PTL_WRITABLE | PTL_PRESENT | PTL_2MB_PAGE)
    
.align 4096
.global ptl_1
ptl_1:
    .quad ptl_2 + (PTL_WRITABLE | PTL_PRESENT)
    .fill 509,8,0
    .quad ptl_2 + (PTL_WRITABLE | PTL_PRESENT)
    .fill 1,8,0
    
.align 4096
.global ptl_0
ptl_0:
    .quad ptl_1 + (PTL_WRITABLE | PTL_PRESENT)
    .fill 510,8,0
    .quad ptl_1 + (PTL_WRITABLE | PTL_PRESENT)

.global real_bootstrap_gdtr_boot
real_bootstrap_gdtr_boot:
    .word gdtselector(GDT_ITEMS)
    .long KA2PA(gdt)-BOOT_OFFSET