/* * relocate_kernel.S - put the kernel image in place to boot * Copyright (C) 2002-2004 Eric Biederman <ebiederm@xmission.com> * * This source code is licensed under the GNU General Public License, * Version 2. See the file COPYING for more details. */ #include <linux/linkage.h> /* * Must be relocatable PIC code callable as a C function, that once * it starts can not use the previous processes stack. */ .globl relocate_new_kernel relocate_new_kernel: /* read the arguments and say goodbye to the stack */ movl 4(%esp), %ebx /* page_list */ movl 8(%esp), %ebp /* reboot_code_buffer */ movl 12(%esp), %edx /* start address */ movl 16(%esp), %ecx /* cpu_has_pae */ /* zero out flags, and disable interrupts */ pushl $0 popfl /* set a new stack at the bottom of our page... */ lea 4096(%ebp), %esp /* store the parameters back on the stack */ pushl %edx /* store the start address */ /* Set cr0 to a known state: * 31 0 == Paging disabled * 18 0 == Alignment check disabled * 16 0 == Write protect disabled * 3 0 == No task switch * 2 0 == Don't do FP software emulation. * 0 1 == Proctected mode enabled */ movl %cr0, %eax andl $~((1<<31)|(1<<18)|(1<<16)|(1<<3)|(1<<2)), %eax orl $(1<<0), %eax movl %eax, %cr0 /* clear cr4 if applicable */ testl %ecx, %ecx jz 1f /* Set cr4 to a known state: * Setting everything to zero seems safe. */ movl %cr4, %eax andl $0, %eax movl %eax, %cr4 jmp 1f 1: /* Flush the TLB (needed?) */ xorl %eax, %eax movl %eax, %cr3 /* Do the copies */ movl %ebx, %ecx jmp 1f 0: /* top, read another word from the indirection page */ movl (%ebx), %ecx addl $4, %ebx 1: testl $0x1, %ecx /* is it a destination page */ jz 2f movl %ecx, %edi andl $0xfffff000, %edi jmp 0b 2: testl $0x2, %ecx /* is it an indirection page */ jz 2f movl %ecx, %ebx andl $0xfffff000, %ebx jmp 0b 2: testl $0x4, %ecx /* is it the done indicator */ jz 2f jmp 3f 2: testl $0x8, %ecx /* is it the source indicator */ jz 0b /* Ignore it otherwise */ movl %ecx, %esi /* For every source page do a copy */ andl $0xfffff000, %esi movl $1024, %ecx rep ; movsl jmp 0b 3: /* To be certain of avoiding problems with self-modifying code * I need to execute a serializing instruction here. * So I flush the TLB, it's handy, and not processor dependent. */ xorl %eax, %eax movl %eax, %cr3 /* set all of the registers to known values */ /* leave %esp alone */ xorl %eax, %eax xorl %ebx, %ebx xorl %ecx, %ecx xorl %edx, %edx xorl %esi, %esi xorl %edi, %edi xorl %ebp, %ebp ret relocate_new_kernel_end: .globl relocate_new_kernel_size relocate_new_kernel_size: .long relocate_new_kernel_end - relocate_new_kernel