diff options
Diffstat (limited to 'arch/i386/kernel/relocate_kernel.S')
| -rw-r--r-- | arch/i386/kernel/relocate_kernel.S | 120 |
1 files changed, 120 insertions, 0 deletions
diff --git a/arch/i386/kernel/relocate_kernel.S b/arch/i386/kernel/relocate_kernel.S new file mode 100644 index 000000000000..d312616effa1 --- /dev/null +++ b/arch/i386/kernel/relocate_kernel.S @@ -0,0 +1,120 @@ +/* + * 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 |