source: mainline/kernel/arch/amd64/src/boot/boot.S@ a1f60f3

#
# Copyright (c) 2005 Ondrej Palkovsky
# Copyright (c) 2006 Martin Decky
# Copyright (c) 2008 Jakub Jermar
# 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.
#

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

#define START_STACK     (BOOT_OFFSET - BOOT_STACK_SIZE)

.section K_TEXT_START, "ax"

.code32
.align 4
.global multiboot_image_start
multiboot_header:
        .long MULTIBOOT_HEADER_MAGIC
        .long MULTIBOOT_HEADER_FLAGS
        .long -(MULTIBOOT_HEADER_MAGIC + MULTIBOOT_HEADER_FLAGS)  # checksum
        .long multiboot_header
        .long unmapped_ktext_start
        .long 0
        .long 0
        .long multiboot_image_start

multiboot_image_start:
        cld
        movl $START_STACK, %esp             # initialize stack pointer
        lgdtl bootstrap_gdtr                # initialize Global Descriptor Table register
        
        movw $gdtselector(KDATA_DES), %cx
        movw %cx, %es
        movw %cx, %ds                       # kernel data + stack
        movw %cx, %ss
        
        #
        # Simics seems to remove hidden part of GS on entering user mode
        # when _visible_ part of GS does not point to user-mode segment.
        #
        
        movw $gdtselector(UDATA_DES), %cx
        movw %cx, %fs
        movw %cx, %gs
        
        jmpl $gdtselector(KTEXT32_DES), $multiboot_meeting_point
        multiboot_meeting_point:
        
        movl %eax, grub_eax                 # save parameters from GRUB
        movl %ebx, grub_ebx
        
        #
        # Protected 32-bit. We want to reuse the code-seg descriptor,
        # the Default operand size must not be 1 when entering long mode.
        #
        
        movl $(INTEL_CPUID_EXTENDED), %eax
        cpuid
        cmp $(INTEL_CPUID_EXTENDED), %eax
        ja extended_cpuid_supported
        
                movl $extended_cpuid_msg, %esi
                jmp error_halt
        
        extended_cpuid_supported:
        
        movl $(AMD_CPUID_EXTENDED), %eax
        cpuid
        bt $(AMD_EXT_LONG_MODE), %edx
        jc long_mode_supported
        
                movl $long_mode_msg, %esi
                jmp error_halt
        
        long_mode_supported:
        
        bt $(AMD_EXT_NOEXECUTE), %edx
        jc noexecute_supported
        
                movl $noexecute_msg, %esi
                jmp error_halt
        
        noexecute_supported:
        
        movl $(INTEL_CPUID_STANDARD), %eax
        cpuid
        bt $(INTEL_FXSAVE), %edx
        jc fx_supported
        
                movl $fx_msg, %esi
                jmp error_halt
        
        fx_supported:
        
        bt $(INTEL_SSE2), %edx
        jc sse2_supported
        
                movl $sse2_msg, %esi
                jmp error_halt
        
        sse2_supported:

#include "vesa_prot.inc"

        #
        # Enable 64-bit page translation 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
        
        # call arch_pre_main(grub_eax, grub_ebx)
        xorq %rdi, %rdi
        movl grub_eax, %edi
        xorq %rsi, %rsi
        movl grub_ebx, %esi
        
        movabsq $arch_pre_main, %rax
        callq *%rax
        
        # create the first stack frame
        pushq $0
        movq %rsp, %rbp
        
        movabsq $main_bsp, %rax
        call *%rax
        
        # not reached
        
        cli
        hlt0:
                hlt
                jmp hlt0

# Print string from %esi to EGA display (in red) and halt
error_halt:
        movl $0xb8000, %edi       # base of EGA text mode memory
        xorl %eax, %eax
        
        movw $0x3d4, %dx          # read bits 8 - 15 of the cursor address
        movb $0xe, %al
        outb %al, %dx
        
        movw $0x3d5, %dx
        inb %dx, %al
        shl $8, %ax
        
        movw $0x3d4, %dx          # read bits 0 - 7 of the cursor address
        movb $0xf, %al
        outb %al, %dx
        
        movw $0x3d5, %dx
        inb %dx, %al
        
        cmp $1920, %ax
        jbe cursor_ok
        
                movw $1920, %ax       # sanity check for the cursor on the last line
        
        cursor_ok:
        
        movw %ax, %bx
        shl $1, %eax
        addl %eax, %edi
        
        movw $0x0c00, %ax         # black background, light red foreground
        
        ploop:
                lodsb
                cmp $0, %al
                je ploop_end
                stosw
                inc %bx
                jmp ploop
        ploop_end:
        
        movw $0x3d4, %dx          # write bits 8 - 15 of the cursor address
        movb $0xe, %al
        outb %al, %dx
        
        movw $0x3d5, %dx
        movb %bh, %al
        outb %al, %dx
        
        movw $0x3d4, %dx          # write bits 0 - 7 of the cursor address
        movb $0xf, %al
        outb %al, %dx
        
        movw $0x3d5, %dx
        movb %bl, %al
        outb %al, %dx
        
        cli
        hlt1:
                hlt
                jmp hlt1

#include "vesa_real.inc"

.section K_INI_PTLS, "aw", @progbits

#
# Macro for generating initial page table contents.
# @param cnt Number of entries to generate. Must be multiple of 8.
# @param g   Number of GB that will be added to the mapping.
#
.macro ptl2gen cnt g
.if \cnt
        ptl2gen "\cnt - 8" \g
        .quad ((\cnt - 8) * 0x200000) + (\g * 1024 * 1024 * 1024) | (PTL_WRITABLE | PTL_PRESENT | PTL_2MB_PAGE)
        .quad ((\cnt - 7) * 0x200000) + (\g * 1024 * 1024 * 1024) | (PTL_WRITABLE | PTL_PRESENT | PTL_2MB_PAGE)
        .quad ((\cnt - 6) * 0x200000) + (\g * 1024 * 1024 * 1024) | (PTL_WRITABLE | PTL_PRESENT | PTL_2MB_PAGE)
        .quad ((\cnt - 5) * 0x200000) + (\g * 1024 * 1024 * 1024) | (PTL_WRITABLE | PTL_PRESENT | PTL_2MB_PAGE)
        .quad ((\cnt - 4) * 0x200000) + (\g * 1024 * 1024 * 1024) | (PTL_WRITABLE | PTL_PRESENT | PTL_2MB_PAGE)
        .quad ((\cnt - 3) * 0x200000) + (\g * 1024 * 1024 * 1024) | (PTL_WRITABLE | PTL_PRESENT | PTL_2MB_PAGE)
        .quad ((\cnt - 2) * 0x200000) + (\g * 1024 * 1024 * 1024) | (PTL_WRITABLE | PTL_PRESENT | PTL_2MB_PAGE)
        .quad ((\cnt - 1) * 0x200000) + (\g * 1024 * 1024 * 1024) | (PTL_WRITABLE | PTL_PRESENT | PTL_2MB_PAGE)
.endif
.endm

# Page table for pages in the first gigabyte.
.align 4096
.global ptl_2_0g
ptl_2_0g:
        ptl2gen 512 0

# Page table for pages in the second gigabyte.
.align 4096
.global ptl_2_1g
ptl_2_1g:
        ptl2gen 512 1

# Page table for pages in the third gigabyte.
.align 4096
.global ptl_2_2g
ptl_2_2g:
        ptl2gen 512 2

# Page table for pages in the fourth gigabyte.
.align 4096
.global ptl_2_3g
ptl_2_3g:
        ptl2gen 512 3

.align 4096
.global ptl_1
ptl_1:
        # Identity mapping for [0; 4G)
        .quad ptl_2_0g + (PTL_WRITABLE | PTL_PRESENT)
        .quad ptl_2_1g + (PTL_WRITABLE | PTL_PRESENT)
        .quad ptl_2_2g + (PTL_WRITABLE | PTL_PRESENT)
        .quad ptl_2_3g + (PTL_WRITABLE | PTL_PRESENT)
        .fill 508, 8, 0

.align 4096
.global ptl_0
ptl_0:
        .quad ptl_1 + (PTL_WRITABLE | PTL_PRESENT)
        .fill 255, 8, 0
        .quad ptl_1 + (PTL_WRITABLE | PTL_PRESENT)
        .fill 255, 8, 0

.section K_DATA_START, "aw", @progbits

.global bootstrap_gdtr
bootstrap_gdtr:
        .word gdtselector(GDT_ITEMS)
        .long KA2PA(gdt)

grub_eax:
        .long 0

grub_ebx:
        .long 0

extended_cpuid_msg:
        .asciz "Error: Extended CPUID not supported -- CPU is not 64-bit. System halted."
long_mode_msg:
        .asciz "Error: 64-bit long mode not supported. System halted."
noexecute_msg:
        .asciz "Error: No-execute pages not supported. System halted."
fx_msg:
        .asciz "Error: FXSAVE/FXRESTORE instructions not supported. System halted."
sse2_msg:
        .asciz "Error: SSE2 instructions not supported. System halted."