source: mainline/kernel/arch/amd64/src/smp/ap.S@ 304342e

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

#
# Init code for application processors.
#

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

.section K_TEXT_START, "ax"

#ifdef CONFIG_SMP

.global unmapped_ap_boot

# This piece of code is real-mode and is meant to be alligned at 4K boundary.
# The requirement for such an alignment comes from MP Specification's STARTUP
# IPI requirements.

.align 4096
unmapped_ap_boot:
.code16
        cli
        xorw %ax, %ax
        movw %ax, %ds

        lgdtl ap_gdtr           # initialize Global Descriptor Table register
        
        movl %cr0, %eax
        orl $1, %eax
        movl %eax, %cr0         # switch to protected mode
        jmpl $gdtselector(KTEXT32_DES), $jump_to_kernel - BOOT_OFFSET + AP_BOOT_OFFSET
        
jump_to_kernel:
.code32
        movw $gdtselector(KDATA_DES), %ax
        movw %ax, %ds
        movw %ax, %es
        movw %ax, %ss
        movw $gdtselector(UDATA_DES), %ax
        movw %ax, %gs
        
        # 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

        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 - BOOT_OFFSET + AP_BOOT_OFFSET

.code64
start64:
        movq (ctx), %rsp
        pushq $0
        movq %rsp, %rbp
        call main_ap - AP_BOOT_OFFSET + BOOT_OFFSET   # never returns

#endif /* CONFIG_SMP */

.section K_DATA_START, "aw", @progbits

#ifdef CONFIG_SMP

.global unmapped_ap_gdtr
unmapped_ap_gdtr:
        .word 0
        .long 0

#endif /* CONFIG_SMP */