/* * relocate_kernel.S - put the kernel image in place to boot * Copyright (C) 2002-2004 Eric Biederman * * This source code is licensed under the GNU General Public License, * Version 2. See the file COPYING for more details. */ #include #include #include /* * Must be relocatable PIC code callable as a C function */ #define PTR(x) (x << 2) #define PAGE_ALIGNED (1 << PAGE_SHIFT) #define PAGE_ATTR 0x63 /* _PAGE_PRESENT|_PAGE_RW|_PAGE_ACCESSED|_PAGE_DIRTY */ #define PAE_PGD_ATTR 0x01 /* _PAGE_PRESENT */ .text .align PAGE_ALIGNED .globl relocate_kernel relocate_kernel: movl 8(%esp), %ebp /* list of pages */ #ifdef CONFIG_X86_PAE /* map the control page at its virtual address */ movl PTR(VA_PGD)(%ebp), %edi movl PTR(VA_CONTROL_PAGE)(%ebp), %eax andl $0xc0000000, %eax shrl $27, %eax addl %edi, %eax movl PTR(PA_PMD_0)(%ebp), %edx orl $PAE_PGD_ATTR, %edx movl %edx, (%eax) movl PTR(VA_PMD_0)(%ebp), %edi movl PTR(VA_CONTROL_PAGE)(%ebp), %eax andl $0x3fe00000, %eax shrl $18, %eax addl %edi, %eax movl PTR(PA_PTE_0)(%ebp), %edx orl $PAGE_ATTR, %edx movl %edx, (%eax) movl PTR(VA_PTE_0)(%ebp), %edi movl PTR(VA_CONTROL_PAGE)(%ebp), %eax andl $0x001ff000, %eax shrl $9, %eax addl %edi, %eax movl PTR(PA_CONTROL_PAGE)(%ebp), %edx orl $PAGE_ATTR, %edx movl %edx, (%eax) /* identity map the control page at its physical address */ movl PTR(VA_PGD)(%ebp), %edi movl PTR(PA_CONTROL_PAGE)(%ebp), %eax andl $0xc0000000, %eax shrl $27, %eax addl %edi, %eax movl PTR(PA_PMD_1)(%ebp), %edx orl $PAE_PGD_ATTR, %edx movl %edx, (%eax) movl PTR(VA_PMD_1)(%ebp), %edi movl PTR(PA_CONTROL_PAGE)(%ebp), %eax andl $0x3fe00000, %eax shrl $18, %eax addl %edi, %eax movl PTR(PA_PTE_1)(%ebp), %edx orl $PAGE_ATTR, %edx movl %edx, (%eax) movl PTR(VA_PTE_1)(%ebp), %edi movl PTR(PA_CONTROL_PAGE)(%ebp), %eax andl $0x001ff000, %eax shrl $9, %eax addl %edi, %eax movl PTR(PA_CONTROL_PAGE)(%ebp), %edx orl $PAGE_ATTR, %edx movl %edx, (%eax) #else /* map the control page at its virtual address */ movl PTR(VA_PGD)(%ebp), %edi movl PTR(VA_CONTROL_PAGE)(%ebp), %eax andl $0xffc00000, %eax shrl $20, %eax addl %edi, %eax movl PTR(PA_PTE_0)(%ebp), %edx orl $PAGE_ATTR, %edx movl %edx, (%eax) movl PTR(VA_PTE_0)(%ebp), %edi movl PTR(VA_CONTROL_PAGE)(%ebp), %eax andl $0x003ff000, %eax shrl $10, %eax addl %edi, %eax movl PTR(PA_CONTROL_PAGE)(%ebp), %edx orl $PAGE_ATTR, %edx movl %edx, (%eax) /* identity map the control page at its physical address */ movl PTR(VA_PGD)(%ebp), %edi movl PTR(PA_CONTROL_PAGE)(%ebp), %eax andl $0xffc00000, %eax shrl $20, %eax addl %edi, %eax movl PTR(PA_PTE_1)(%ebp), %edx orl $PAGE_ATTR, %edx movl %edx, (%eax) movl PTR(VA_PTE_1)(%ebp), %edi movl PTR(PA_CONTROL_PAGE)(%ebp), %eax andl $0x003ff000, %eax shrl $10, %eax addl %edi, %eax movl PTR(PA_CONTROL_PAGE)(%ebp), %edx orl $PAGE_ATTR, %edx movl %edx, (%eax) #endif relocate_new_kernel: /* read the arguments and say goodbye to the stack */ movl 4(%esp), %ebx /* page_list */ movl 8(%esp), %ebp /* list of pages */ movl 12(%esp), %edx /* start address */ movl 16(%esp), %ecx /* cpu_has_pae */ /* zero out flags, and disable interrupts */ pushl $0 popfl /* get physical address of control page now */ /* this is impossible after page table switch */ movl PTR(PA_CONTROL_PAGE)(%ebp), %edi /* switch to new set of page tables */ movl PTR(PA_PGD)(%ebp), %eax movl %eax, %cr3 /* setup a new stack at the end of the physical control page */ lea 4096(%edi), %esp /* jump to identity mapped page */ movl %edi, %eax addl $(identity_mapped - relocate_kernel), %eax pushl %eax ret identity_mapped: /* store the start address on the stack */ pushl %edx /* 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