/* * relocate_kernel.S - put the kernel image in place to boot * Copyright (C) 2002-2005 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 #include #include /* * Must be relocatable PIC code callable as a C function */ #define PTR(x) (x << 3) #define PAGE_ATTR (_PAGE_PRESENT | _PAGE_RW | _PAGE_ACCESSED | _PAGE_DIRTY) .text .align PAGE_SIZE .code64 .globl relocate_kernel relocate_kernel: /* %rdi indirection_page * %rsi page_list * %rdx start address */ /* map the control page at its virtual address */ movq $0x0000ff8000000000, %r10 /* mask */ mov $(39 - 3), %cl /* bits to shift */ movq PTR(VA_CONTROL_PAGE)(%rsi), %r11 /* address to map */ movq %r11, %r9 andq %r10, %r9 shrq %cl, %r9 movq PTR(VA_PGD)(%rsi), %r8 addq %r8, %r9 movq PTR(PA_PUD_0)(%rsi), %r8 orq $PAGE_ATTR, %r8 movq %r8, (%r9) shrq $9, %r10 sub $9, %cl movq %r11, %r9 andq %r10, %r9 shrq %cl, %r9 movq PTR(VA_PUD_0)(%rsi), %r8 addq %r8, %r9 movq PTR(PA_PMD_0)(%rsi), %r8 orq $PAGE_ATTR, %r8 movq %r8, (%r9) shrq $9, %r10 sub $9, %cl movq %r11, %r9 andq %r10, %r9 shrq %cl, %r9 movq PTR(VA_PMD_0)(%rsi), %r8 addq %r8, %r9 movq PTR(PA_PTE_0)(%rsi), %r8 orq $PAGE_ATTR, %r8 movq %r8, (%r9) shrq $9, %r10 sub $9, %cl movq %r11, %r9 andq %r10, %r9 shrq %cl, %r9 movq PTR(VA_PTE_0)(%rsi), %r8 addq %r8, %r9 movq PTR(PA_CONTROL_PAGE)(%rsi), %r8 orq $PAGE_ATTR, %r8 movq %r8, (%r9) /* identity map the control page at its physical address */ movq $0x0000ff8000000000, %r10 /* mask */ mov $(39 - 3), %cl /* bits to shift */ movq PTR(PA_CONTROL_PAGE)(%rsi), %r11 /* address to map */ movq %r11, %r9 andq %r10, %r9 shrq %cl, %r9 movq PTR(VA_PGD)(%rsi), %r8 addq %r8, %r9 movq PTR(PA_PUD_1)(%rsi), %r8 orq $PAGE_ATTR, %r8 movq %r8, (%r9) shrq $9, %r10 sub $9, %cl movq %r11, %r9 andq %r10, %r9 shrq %cl, %r9 movq PTR(VA_PUD_1)(%rsi), %r8 addq %r8, %r9 movq PTR(PA_PMD_1)(%rsi), %r8 orq $PAGE_ATTR, %r8 movq %r8, (%r9) shrq $9, %r10 sub $9, %cl movq %r11, %r9 andq %r10, %r9 shrq %cl, %r9 movq PTR(VA_PMD_1)(%rsi), %r8 addq %r8, %r9 movq PTR(PA_PTE_1)(%rsi), %r8 orq $PAGE_ATTR, %r8 movq %r8, (%r9) shrq $9, %r10 sub $9, %cl movq %r11, %r9 andq %r10, %r9 shrq %cl, %r9 movq PTR(VA_PTE_1)(%rsi), %r8 addq %r8, %r9 movq PTR(PA_CONTROL_PAGE)(%rsi), %r8 orq $PAGE_ATTR, %r8 movq %r8, (%r9) relocate_new_kernel: /* %rdi indirection_page * %rsi page_list * %rdx start address */ /* zero out flags, and disable interrupts */ pushq $0 popfq /* get physical address of control page now */ /* this is impossible after page table switch */ movq PTR(PA_CONTROL_PAGE)(%rsi), %r8 /* get physical address of page table now too */ movq PTR(PA_TABLE_PAGE)(%rsi), %rcx /* switch to new set of page tables */ movq PTR(PA_PGD)(%rsi), %r9 movq %r9, %cr3 /* setup a new stack at the end of the physical control page */ lea PAGE_SIZE(%r8), %rsp /* jump to identity mapped page */ addq $(identity_mapped - relocate_kernel), %r8 pushq %r8 ret identity_mapped: /* store the start address on the stack */ pushq %rdx /* Set cr0 to a known state: * - Paging enabled * - Alignment check disabled * - Write protect disabled * - No task switch * - Don't do FP software emulation. * - Proctected mode enabled */ movq %cr0, %rax andq $~(X86_CR0_AM | X86_CR0_WP | X86_CR0_TS | X86_CR0_EM), %rax orl $(X86_CR0_PG | X86_CR0_PE), %eax movq %rax, %cr0 /* Set cr4 to a known state: * - physical address extension enabled */ movq $X86_CR4_PAE, %rax movq %rax, %cr4 jmp 1f 1: /* Switch to the identity mapped page tables, * and flush the TLB. */ movq %rcx, %cr3 /* Do the copies */ movq %rdi, %rcx /* Put the page_list in %rcx */ xorq %rdi, %rdi xorq %rsi, %rsi jmp 1f 0: /* top, read another word for the indirection page */ movq (%rbx), %rcx addq $8, %rbx 1: testq $0x1, %rcx /* is it a destination page? */ jz 2f movq %rcx, %rdi andq $0xfffffffffffff000, %rdi jmp 0b 2: testq $0x2, %rcx /* is it an indirection page? */ jz 2f movq %rcx, %rbx andq $0xfffffffffffff000, %rbx jmp 0b 2: testq $0x4, %rcx /* is it the done indicator? */ jz 2f jmp 3f 2: testq $0x8, %rcx /* is it the source indicator? */ jz 0b /* Ignore it otherwise */ movq %rcx, %rsi /* For ever source page do a copy */ andq $0xfffffffffffff000, %rsi movq $512, %rcx rep ; movsq 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 by reloading %cr3 here, it's handy, * and not processor dependent. */ movq %cr3, %rax movq %rax, %cr3 /* set all of the registers to known values */ /* leave %rsp alone */ xorq %rax, %rax xorq %rbx, %rbx xorq %rcx, %rcx xorq %rdx, %rdx xorq %rsi, %rsi xorq %rdi, %rdi xorq %rbp, %rbp xorq %r8, %r8 xorq %r9, %r9 xorq %r10, %r9 xorq %r11, %r11 xorq %r12, %r12 xorq %r13, %r13 xorq %r14, %r14 xorq %r15, %r15 ret