393 строки
9.3 KiB
ArmAsm
393 строки
9.3 KiB
ArmAsm
/*
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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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#include <linux/linkage.h>
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#include <linux/threads.h>
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#include <linux/init.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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.section .bootstrap.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 $(boot_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 $(boot_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. In addition we need to ensure %cs is set so we make this
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* a far return.
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*/
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movq initial_code(%rip),%rax
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pushq $0 # fake return address to stop unwinder
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pushq $__KERNEL_CS # set correct cs
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pushq %rax # target address in negative space
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lretq
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/* SMP bootup changes these two */
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.align 8
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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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#ifdef CONFIG_KALLSYMS
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leaq early_idt_ripmsg(%rip),%rdi
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movq 8(%rsp),%rsi # get rip again
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call __print_symbol
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#endif
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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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early_idt_ripmsg:
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.asciz "RIP %s\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-1
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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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$page = 0
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#define NEXT_PAGE(name) \
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$page = $page + 1; \
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.org $page * 0x1000; \
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phys_/**/name = $page * 0x1000 + __PHYSICAL_START; \
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ENTRY(name)
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NEXT_PAGE(init_level4_pgt)
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/* This gets initialized in x86_64_start_kernel */
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.fill 512,8,0
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NEXT_PAGE(level3_ident_pgt)
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.quad phys_level2_ident_pgt | 0x007
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.fill 511,8,0
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NEXT_PAGE(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 phys_level2_kernel_pgt | 0x007
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.fill 1,8,0
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NEXT_PAGE(level2_ident_pgt)
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/* 40MB for bootup. */
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i = 0
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.rept 20
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.quad i << 21 | 0x083
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i = i + 1
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.endr
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/* Temporary mappings for the super early allocator in arch/x86_64/mm/init.c */
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.globl temp_boot_pmds
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temp_boot_pmds:
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.fill 492,8,0
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NEXT_PAGE(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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i = 0
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.rept 20
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.quad i << 21 | 0x183
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i = i + 1
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.endr
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/* Module mapping starts here */
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.fill 492,8,0
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NEXT_PAGE(level3_physmem_pgt)
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.quad phys_level2_kernel_pgt | 0x007 /* so that __va works even before pagetable_init */
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.fill 511,8,0
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#undef NEXT_PAGE
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.data
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#ifdef CONFIG_ACPI_SLEEP
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.align PAGE_SIZE
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ENTRY(wakeup_level4_pgt)
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.quad phys_level3_ident_pgt | 0x007
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.fill 255,8,0
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.quad phys_level3_physmem_pgt | 0x007
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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 phys_level3_kernel_pgt | 0x007
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#endif
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#ifndef CONFIG_HOTPLUG_CPU
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__INITDATA
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#endif
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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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.align PAGE_SIZE
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ENTRY(boot_level4_pgt)
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.quad phys_level3_ident_pgt | 0x007
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.fill 255,8,0
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.quad phys_level3_physmem_pgt | 0x007
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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 phys_level3_kernel_pgt | 0x007
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.data
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.align 16
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.globl cpu_gdt_descr
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cpu_gdt_descr:
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.word gdt_end-cpu_gdt_table-1
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gdt:
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.quad cpu_gdt_table
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#ifdef CONFIG_SMP
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.rept NR_CPUS-1
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.word 0
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.quad 0
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.endr
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#endif
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/* We need valid kernel segments for data and code in long mode too
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* IRET will check the segment types kkeil 2000/10/28
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* Also sysret mandates a special GDT layout
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*/
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.section .data.page_aligned, "aw"
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.align PAGE_SIZE
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/* The TLS descriptors are currently at a different place compared to i386.
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Hopefully nobody expects them at a fixed place (Wine?) */
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ENTRY(cpu_gdt_table)
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.quad 0x0000000000000000 /* NULL descriptor */
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.quad 0x0 /* unused */
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.quad 0x00af9a000000ffff /* __KERNEL_CS */
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.quad 0x00cf92000000ffff /* __KERNEL_DS */
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.quad 0x00cffa000000ffff /* __USER32_CS */
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.quad 0x00cff2000000ffff /* __USER_DS, __USER32_DS */
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.quad 0x00affa000000ffff /* __USER_CS */
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.quad 0x00cf9a000000ffff /* __KERNEL32_CS */
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.quad 0,0 /* TSS */
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.quad 0,0 /* LDT */
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.quad 0,0,0 /* three TLS descriptors */
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.quad 0x0000f40000000000 /* node/CPU stored in limit */
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gdt_end:
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/* asm/segment.h:GDT_ENTRIES must match this */
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/* This should be a multiple of the cache line size */
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/* GDTs of other CPUs are now dynamically allocated */
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/* zero the remaining page */
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.fill PAGE_SIZE / 8 - GDT_ENTRIES,8,0
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.section .bss, "aw", @nobits
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.align L1_CACHE_BYTES
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ENTRY(idt_table)
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.skip 256 * 16
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.section .bss.page_aligned, "aw", @nobits
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.align PAGE_SIZE
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ENTRY(empty_zero_page)
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.skip PAGE_SIZE
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