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/*
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* linux/arch/x86_64/kernel/head.S -- start in 32bit and switch to 64bit
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*
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* Copyright (C) 2000 Andrea Arcangeli <andrea@suse.de> SuSE
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* Copyright (C) 2000 Pavel Machek <pavel@suse.cz>
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* Copyright (C) 2000 Karsten Keil <kkeil@suse.de>
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* Copyright (C) 2001,2002 Andi Kleen <ak@suse.de>
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*
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* $Id: head.S,v 1.49 2002/03/19 17:39:25 ak Exp $
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*/
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#include <linux/linkage.h>
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#include <linux/threads.h>
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#include <asm/desc.h>
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#include <asm/segment.h>
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#include <asm/page.h>
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#include <asm/msr.h>
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#include <asm/cache.h>
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/* we are not able to switch in one step to the final KERNEL ADRESS SPACE
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* because we need identity-mapped pages on setup so define __START_KERNEL to
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* 0x100000 for this stage
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*
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*/
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.text
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.code32
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.globl startup_32
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/* %bx: 1 if coming from smp trampoline on secondary cpu */
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startup_32:
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/*
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* At this point the CPU runs in 32bit protected mode (CS.D = 1) with
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* paging disabled and the point of this file is to switch to 64bit
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* long mode with a kernel mapping for kerneland to jump into the
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* kernel virtual addresses.
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* There is no stack until we set one up.
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*/
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/* Initialize the %ds segment register */
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movl $__KERNEL_DS,%eax
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movl %eax,%ds
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/* Load new GDT with the 64bit segments using 32bit descriptor */
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lgdt pGDT32 - __START_KERNEL_map
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/* If the CPU doesn't support CPUID this will double fault.
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* Unfortunately it is hard to check for CPUID without a stack.
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*/
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/* Check if extended functions are implemented */
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movl $0x80000000, %eax
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cpuid
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cmpl $0x80000000, %eax
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jbe no_long_mode
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/* Check if long mode is implemented */
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mov $0x80000001, %eax
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cpuid
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btl $29, %edx
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jnc no_long_mode
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/*
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* Prepare for entering 64bits mode
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*/
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/* Enable PAE mode */
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xorl %eax, %eax
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btsl $5, %eax
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movl %eax, %cr4
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/* Setup early boot stage 4 level pagetables */
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movl $(init_level4_pgt - __START_KERNEL_map), %eax
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movl %eax, %cr3
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/* Setup EFER (Extended Feature Enable Register) */
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movl $MSR_EFER, %ecx
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rdmsr
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/* Enable Long Mode */
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btsl $_EFER_LME, %eax
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/* Make changes effective */
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wrmsr
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xorl %eax, %eax
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btsl $31, %eax /* Enable paging and in turn activate Long Mode */
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btsl $0, %eax /* Enable protected mode */
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/* Make changes effective */
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movl %eax, %cr0
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/*
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* At this point we're in long mode but in 32bit compatibility mode
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* with EFER.LME = 1, CS.L = 0, CS.D = 1 (and in turn
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* EFER.LMA = 1). Now we want to jump in 64bit mode, to do that we use
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* the new gdt/idt that has __KERNEL_CS with CS.L = 1.
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*/
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ljmp $__KERNEL_CS, $(startup_64 - __START_KERNEL_map)
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.code64
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.org 0x100
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.globl startup_64
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startup_64:
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/* We come here either from startup_32
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* or directly from a 64bit bootloader.
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* Since we may have come directly from a bootloader we
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* reload the page tables here.
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*/
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/* Enable PAE mode and PGE */
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xorq %rax, %rax
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btsq $5, %rax
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btsq $7, %rax
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movq %rax, %cr4
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/* Setup early boot stage 4 level pagetables. */
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movq $(init_level4_pgt - __START_KERNEL_map), %rax
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movq %rax, %cr3
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/* Check if nx is implemented */
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movl $0x80000001, %eax
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cpuid
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movl %edx,%edi
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/* Setup EFER (Extended Feature Enable Register) */
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movl $MSR_EFER, %ecx
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rdmsr
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/* Enable System Call */
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btsl $_EFER_SCE, %eax
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/* No Execute supported? */
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btl $20,%edi
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jnc 1f
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btsl $_EFER_NX, %eax
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1:
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/* Make changes effective */
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wrmsr
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/* Setup cr0 */
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#define CR0_PM 1 /* protected mode */
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#define CR0_MP (1<<1)
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#define CR0_ET (1<<4)
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#define CR0_NE (1<<5)
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#define CR0_WP (1<<16)
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#define CR0_AM (1<<18)
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#define CR0_PAGING (1<<31)
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movl $CR0_PM|CR0_MP|CR0_ET|CR0_NE|CR0_WP|CR0_AM|CR0_PAGING,%eax
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/* Make changes effective */
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movq %rax, %cr0
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/* Setup a boot time stack */
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movq init_rsp(%rip),%rsp
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/* zero EFLAGS after setting rsp */
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pushq $0
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popfq
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/*
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* We must switch to a new descriptor in kernel space for the GDT
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* because soon the kernel won't have access anymore to the userspace
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* addresses where we're currently running on. We have to do that here
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* because in 32bit we couldn't load a 64bit linear address.
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*/
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lgdt cpu_gdt_descr
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/*
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* Setup up a dummy PDA. this is just for some early bootup code
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* that does in_interrupt()
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*/
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movl $MSR_GS_BASE,%ecx
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movq $empty_zero_page,%rax
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movq %rax,%rdx
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shrq $32,%rdx
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wrmsr
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/* set up data segments. actually 0 would do too */
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movl $__KERNEL_DS,%eax
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movl %eax,%ds
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movl %eax,%ss
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movl %eax,%es
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/* esi is pointer to real mode structure with interesting info.
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pass it to C */
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movl %esi, %edi
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/* Finally jump to run C code and to be on real kernel address
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* Since we are running on identity-mapped space we have to jump
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* to the full 64bit address , this is only possible as indirect
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* jump
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*/
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movq initial_code(%rip),%rax
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jmp *%rax
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/* SMP bootup changes these two */
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.globl initial_code
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initial_code:
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.quad x86_64_start_kernel
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.globl init_rsp
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init_rsp:
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.quad init_thread_union+THREAD_SIZE-8
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ENTRY(early_idt_handler)
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cmpl $2,early_recursion_flag(%rip)
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jz 1f
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incl early_recursion_flag(%rip)
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xorl %eax,%eax
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movq 8(%rsp),%rsi # get rip
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movq (%rsp),%rdx
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movq %cr2,%rcx
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leaq early_idt_msg(%rip),%rdi
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call early_printk
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cmpl $2,early_recursion_flag(%rip)
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jz 1f
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call dump_stack
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1: hlt
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jmp 1b
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early_recursion_flag:
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.long 0
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early_idt_msg:
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.asciz "PANIC: early exception rip %lx error %lx cr2 %lx\n"
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.code32
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ENTRY(no_long_mode)
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/* This isn't an x86-64 CPU so hang */
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1:
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jmp 1b
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.org 0xf00
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.globl pGDT32
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pGDT32:
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.word gdt_end-cpu_gdt_table
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.long cpu_gdt_table-__START_KERNEL_map
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.org 0xf10
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ljumpvector:
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.long startup_64-__START_KERNEL_map
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.word __KERNEL_CS
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ENTRY(stext)
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ENTRY(_stext)
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/*
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* This default setting generates an ident mapping at address 0x100000
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* and a mapping for the kernel that precisely maps virtual address
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* 0xffffffff80000000 to physical address 0x000000. (always using
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* 2Mbyte large pages provided by PAE mode)
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*/
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.org 0x1000
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ENTRY(init_level4_pgt)
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.quad 0x0000000000002007 + __PHYSICAL_START /* -> level3_ident_pgt */
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.fill 255,8,0
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.quad 0x000000000000a007 + __PHYSICAL_START
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.fill 254,8,0
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/* (2^48-(2*1024*1024*1024))/(2^39) = 511 */
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.quad 0x0000000000003007 + __PHYSICAL_START /* -> level3_kernel_pgt */
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.org 0x2000
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ENTRY(level3_ident_pgt)
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.quad 0x0000000000004007 + __PHYSICAL_START
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.fill 511,8,0
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.org 0x3000
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ENTRY(level3_kernel_pgt)
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.fill 510,8,0
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/* (2^48-(2*1024*1024*1024)-((2^39)*511))/(2^30) = 510 */
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.quad 0x0000000000005007 + __PHYSICAL_START /* -> level2_kernel_pgt */
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.fill 1,8,0
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.org 0x4000
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ENTRY(level2_ident_pgt)
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/* 40MB for bootup. */
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.quad 0x0000000000000283
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.quad 0x0000000000200183
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.quad 0x0000000000400183
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.quad 0x0000000000600183
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.quad 0x0000000000800183
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.quad 0x0000000000A00183
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.quad 0x0000000000C00183
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.quad 0x0000000000E00183
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.quad 0x0000000001000183
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.quad 0x0000000001200183
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.quad 0x0000000001400183
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.quad 0x0000000001600183
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.quad 0x0000000001800183
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.quad 0x0000000001A00183
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.quad 0x0000000001C00183
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.quad 0x0000000001E00183
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.quad 0x0000000002000183
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.quad 0x0000000002200183
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.quad 0x0000000002400183
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.quad 0x0000000002600183
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|
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/* Temporary mappings for the super early allocator in arch/x86_64/mm/init.c */
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|
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.globl temp_boot_pmds
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temp_boot_pmds:
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|
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.fill 492,8,0
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|
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.org 0x5000
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ENTRY(level2_kernel_pgt)
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/* 40MB kernel mapping. The kernel code cannot be bigger than that.
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When you change this change KERNEL_TEXT_SIZE in page.h too. */
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/* (2^48-(2*1024*1024*1024)-((2^39)*511)-((2^30)*510)) = 0 */
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.quad 0x0000000000000183
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.quad 0x0000000000200183
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|
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.quad 0x0000000000400183
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|
|
.quad 0x0000000000600183
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|
|
.quad 0x0000000000800183
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|
|
|
.quad 0x0000000000A00183
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|
|
|
.quad 0x0000000000C00183
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|
|
|
.quad 0x0000000000E00183
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|
|
|
.quad 0x0000000001000183
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|
|
|
.quad 0x0000000001200183
|
|
|
|
.quad 0x0000000001400183
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|
|
|
.quad 0x0000000001600183
|
|
|
|
.quad 0x0000000001800183
|
|
|
|
.quad 0x0000000001A00183
|
|
|
|
.quad 0x0000000001C00183
|
|
|
|
.quad 0x0000000001E00183
|
|
|
|
.quad 0x0000000002000183
|
|
|
|
.quad 0x0000000002200183
|
|
|
|
.quad 0x0000000002400183
|
|
|
|
.quad 0x0000000002600183
|
|
|
|
/* Module mapping starts here */
|
|
|
|
.fill 492,8,0
|
|
|
|
|
|
|
|
.org 0x6000
|
|
|
|
ENTRY(empty_zero_page)
|
|
|
|
|
|
|
|
.org 0x7000
|
|
|
|
ENTRY(empty_bad_page)
|
|
|
|
|
|
|
|
.org 0x8000
|
|
|
|
ENTRY(empty_bad_pte_table)
|
|
|
|
|
|
|
|
.org 0x9000
|
|
|
|
ENTRY(empty_bad_pmd_table)
|
|
|
|
|
|
|
|
.org 0xa000
|
|
|
|
ENTRY(level3_physmem_pgt)
|
|
|
|
.quad 0x0000000000005007 + __PHYSICAL_START /* -> level2_kernel_pgt (so that __va works even before pagetable_init) */
|
|
|
|
|
|
|
|
.org 0xb000
|
|
|
|
#ifdef CONFIG_ACPI_SLEEP
|
|
|
|
ENTRY(wakeup_level4_pgt)
|
|
|
|
.quad 0x0000000000002007 + __PHYSICAL_START /* -> level3_ident_pgt */
|
|
|
|
.fill 255,8,0
|
|
|
|
.quad 0x000000000000a007 + __PHYSICAL_START
|
|
|
|
.fill 254,8,0
|
|
|
|
/* (2^48-(2*1024*1024*1024))/(2^39) = 511 */
|
|
|
|
.quad 0x0000000000003007 + __PHYSICAL_START /* -> level3_kernel_pgt */
|
|
|
|
#endif
|
|
|
|
|
|
|
|
.data
|
|
|
|
|
|
|
|
.align 16
|
|
|
|
.globl cpu_gdt_descr
|
|
|
|
cpu_gdt_descr:
|
|
|
|
.word gdt_end-cpu_gdt_table
|
|
|
|
gdt:
|
|
|
|
.quad cpu_gdt_table
|
|
|
|
#ifdef CONFIG_SMP
|
|
|
|
.rept NR_CPUS-1
|
|
|
|
.word 0
|
|
|
|
.quad 0
|
|
|
|
.endr
|
|
|
|
#endif
|
|
|
|
|
|
|
|
/* We need valid kernel segments for data and code in long mode too
|
|
|
|
* IRET will check the segment types kkeil 2000/10/28
|
|
|
|
* Also sysret mandates a special GDT layout
|
|
|
|
*/
|
|
|
|
|
|
|
|
.align L1_CACHE_BYTES
|
|
|
|
|
|
|
|
/* The TLS descriptors are currently at a different place compared to i386.
|
|
|
|
Hopefully nobody expects them at a fixed place (Wine?) */
|
|
|
|
|
|
|
|
ENTRY(cpu_gdt_table)
|
|
|
|
.quad 0x0000000000000000 /* NULL descriptor */
|
|
|
|
.quad 0x008f9a000000ffff /* __KERNEL_COMPAT32_CS */
|
|
|
|
.quad 0x00af9a000000ffff /* __KERNEL_CS */
|
|
|
|
.quad 0x00cf92000000ffff /* __KERNEL_DS */
|
|
|
|
.quad 0x00cffa000000ffff /* __USER32_CS */
|
|
|
|
.quad 0x00cff2000000ffff /* __USER_DS, __USER32_DS */
|
|
|
|
.quad 0x00affa000000ffff /* __USER_CS */
|
|
|
|
.quad 0x00cf9a000000ffff /* __KERNEL32_CS */
|
|
|
|
.quad 0,0 /* TSS */
|
|
|
|
.quad 0,0 /* LDT */
|
|
|
|
.quad 0,0,0 /* three TLS descriptors */
|
|
|
|
.quad 0x00009a000000ffff /* __KERNEL16_CS - 16bit PM for S3 wakeup. */
|
|
|
|
/* base must be patched for real base address. */
|
|
|
|
gdt_end:
|
|
|
|
/* asm/segment.h:GDT_ENTRIES must match this */
|
|
|
|
/* This should be a multiple of the cache line size */
|
|
|
|
/* GDTs of other CPUs: */
|
|
|
|
.fill (GDT_SIZE * NR_CPUS) - (gdt_end - cpu_gdt_table)
|
|
|
|
|
|
|
|
.align L1_CACHE_BYTES
|
|
|
|
ENTRY(idt_table)
|
|
|
|
.rept 256
|
|
|
|
.quad 0
|
|
|
|
.quad 0
|
|
|
|
.endr
|
|
|
|
|