| /* |
| * linux/arch/x86_64/kernel/head.S -- start in 32bit and switch to 64bit |
| * |
| * Copyright (C) 2000 Andrea Arcangeli <andrea@suse.de> SuSE |
| * Copyright (C) 2000 Pavel Machek <pavel@suse.cz> |
| * Copyright (C) 2000 Karsten Keil <kkeil@suse.de> |
| * Copyright (C) 2001,2002 Andi Kleen <ak@suse.de> |
| * Copyright (C) 2005 Eric Biederman <ebiederm@xmission.com> |
| */ |
| |
| |
| #include <linux/linkage.h> |
| #include <linux/threads.h> |
| #include <linux/init.h> |
| #include <asm/segment.h> |
| #include <asm/pgtable.h> |
| #include <asm/page.h> |
| #include <asm/msr.h> |
| #include <asm/cache.h> |
| #include <asm/processor-flags.h> |
| #include <asm/percpu.h> |
| |
| #ifdef CONFIG_PARAVIRT |
| #include <asm/asm-offsets.h> |
| #include <asm/paravirt.h> |
| #else |
| #define GET_CR2_INTO_RCX movq %cr2, %rcx |
| #endif |
| |
| /* we are not able to switch in one step to the final KERNEL ADRESS SPACE |
| * because we need identity-mapped pages. |
| * |
| */ |
| |
| #define pud_index(x) (((x) >> PUD_SHIFT) & (PTRS_PER_PUD-1)) |
| |
| L4_PAGE_OFFSET = pgd_index(__PAGE_OFFSET) |
| L3_PAGE_OFFSET = pud_index(__PAGE_OFFSET) |
| L4_START_KERNEL = pgd_index(__START_KERNEL_map) |
| L3_START_KERNEL = pud_index(__START_KERNEL_map) |
| |
| .text |
| .section .text.head |
| .code64 |
| .globl startup_64 |
| startup_64: |
| |
| /* |
| * At this point the CPU runs in 64bit mode CS.L = 1 CS.D = 1, |
| * and someone has loaded an identity mapped page table |
| * for us. These identity mapped page tables map all of the |
| * kernel pages and possibly all of memory. |
| * |
| * %esi holds a physical pointer to real_mode_data. |
| * |
| * We come here either directly from a 64bit bootloader, or from |
| * arch/x86_64/boot/compressed/head.S. |
| * |
| * We only come here initially at boot nothing else comes here. |
| * |
| * Since we may be loaded at an address different from what we were |
| * compiled to run at we first fixup the physical addresses in our page |
| * tables and then reload them. |
| */ |
| |
| /* Compute the delta between the address I am compiled to run at and the |
| * address I am actually running at. |
| */ |
| leaq _text(%rip), %rbp |
| subq $_text - __START_KERNEL_map, %rbp |
| |
| /* Is the address not 2M aligned? */ |
| movq %rbp, %rax |
| andl $~PMD_PAGE_MASK, %eax |
| testl %eax, %eax |
| jnz bad_address |
| |
| /* Is the address too large? */ |
| leaq _text(%rip), %rdx |
| movq $PGDIR_SIZE, %rax |
| cmpq %rax, %rdx |
| jae bad_address |
| |
| /* Fixup the physical addresses in the page table |
| */ |
| addq %rbp, init_level4_pgt + 0(%rip) |
| addq %rbp, init_level4_pgt + (L4_PAGE_OFFSET*8)(%rip) |
| addq %rbp, init_level4_pgt + (L4_START_KERNEL*8)(%rip) |
| |
| addq %rbp, level3_ident_pgt + 0(%rip) |
| |
| addq %rbp, level3_kernel_pgt + (510*8)(%rip) |
| addq %rbp, level3_kernel_pgt + (511*8)(%rip) |
| |
| addq %rbp, level2_fixmap_pgt + (506*8)(%rip) |
| |
| /* Add an Identity mapping if I am above 1G */ |
| leaq _text(%rip), %rdi |
| andq $PMD_PAGE_MASK, %rdi |
| |
| movq %rdi, %rax |
| shrq $PUD_SHIFT, %rax |
| andq $(PTRS_PER_PUD - 1), %rax |
| jz ident_complete |
| |
| leaq (level2_spare_pgt - __START_KERNEL_map + _KERNPG_TABLE)(%rbp), %rdx |
| leaq level3_ident_pgt(%rip), %rbx |
| movq %rdx, 0(%rbx, %rax, 8) |
| |
| movq %rdi, %rax |
| shrq $PMD_SHIFT, %rax |
| andq $(PTRS_PER_PMD - 1), %rax |
| leaq __PAGE_KERNEL_IDENT_LARGE_EXEC(%rdi), %rdx |
| leaq level2_spare_pgt(%rip), %rbx |
| movq %rdx, 0(%rbx, %rax, 8) |
| ident_complete: |
| |
| /* |
| * Fixup the kernel text+data virtual addresses. Note that |
| * we might write invalid pmds, when the kernel is relocated |
| * cleanup_highmap() fixes this up along with the mappings |
| * beyond _end. |
| */ |
| |
| leaq level2_kernel_pgt(%rip), %rdi |
| leaq 4096(%rdi), %r8 |
| /* See if it is a valid page table entry */ |
| 1: testq $1, 0(%rdi) |
| jz 2f |
| addq %rbp, 0(%rdi) |
| /* Go to the next page */ |
| 2: addq $8, %rdi |
| cmp %r8, %rdi |
| jne 1b |
| |
| /* Fixup phys_base */ |
| addq %rbp, phys_base(%rip) |
| |
| #ifdef CONFIG_X86_TRAMPOLINE |
| addq %rbp, trampoline_level4_pgt + 0(%rip) |
| addq %rbp, trampoline_level4_pgt + (511*8)(%rip) |
| #endif |
| |
| /* Due to ENTRY(), sometimes the empty space gets filled with |
| * zeros. Better take a jmp than relying on empty space being |
| * filled with 0x90 (nop) |
| */ |
| jmp secondary_startup_64 |
| ENTRY(secondary_startup_64) |
| /* |
| * At this point the CPU runs in 64bit mode CS.L = 1 CS.D = 1, |
| * and someone has loaded a mapped page table. |
| * |
| * %esi holds a physical pointer to real_mode_data. |
| * |
| * We come here either from startup_64 (using physical addresses) |
| * or from trampoline.S (using virtual addresses). |
| * |
| * Using virtual addresses from trampoline.S removes the need |
| * to have any identity mapped pages in the kernel page table |
| * after the boot processor executes this code. |
| */ |
| |
| /* Enable PAE mode and PGE */ |
| movl $(X86_CR4_PAE | X86_CR4_PGE), %eax |
| movq %rax, %cr4 |
| |
| /* Setup early boot stage 4 level pagetables. */ |
| movq $(init_level4_pgt - __START_KERNEL_map), %rax |
| addq phys_base(%rip), %rax |
| movq %rax, %cr3 |
| |
| /* Ensure I am executing from virtual addresses */ |
| movq $1f, %rax |
| jmp *%rax |
| 1: |
| |
| /* Check if nx is implemented */ |
| movl $0x80000001, %eax |
| cpuid |
| movl %edx,%edi |
| |
| /* Setup EFER (Extended Feature Enable Register) */ |
| movl $MSR_EFER, %ecx |
| rdmsr |
| btsl $_EFER_SCE, %eax /* Enable System Call */ |
| btl $20,%edi /* No Execute supported? */ |
| jnc 1f |
| btsl $_EFER_NX, %eax |
| 1: wrmsr /* Make changes effective */ |
| |
| /* Setup cr0 */ |
| #define CR0_STATE (X86_CR0_PE | X86_CR0_MP | X86_CR0_ET | \ |
| X86_CR0_NE | X86_CR0_WP | X86_CR0_AM | \ |
| X86_CR0_PG) |
| movl $CR0_STATE, %eax |
| /* Make changes effective */ |
| movq %rax, %cr0 |
| |
| /* Setup a boot time stack */ |
| movq stack_start(%rip),%rsp |
| |
| /* zero EFLAGS after setting rsp */ |
| pushq $0 |
| popfq |
| |
| /* |
| * We must switch to a new descriptor in kernel space for the GDT |
| * because soon the kernel won't have access anymore to the userspace |
| * addresses where we're currently running on. We have to do that here |
| * because in 32bit we couldn't load a 64bit linear address. |
| */ |
| lgdt early_gdt_descr(%rip) |
| |
| /* set up data segments. actually 0 would do too */ |
| movl $__KERNEL_DS,%eax |
| movl %eax,%ds |
| movl %eax,%ss |
| movl %eax,%es |
| |
| /* |
| * We don't really need to load %fs or %gs, but load them anyway |
| * to kill any stale realmode selectors. This allows execution |
| * under VT hardware. |
| */ |
| movl %eax,%fs |
| movl %eax,%gs |
| |
| /* Set up %gs. |
| * |
| * The base of %gs always points to the bottom of the irqstack |
| * union. If the stack protector canary is enabled, it is |
| * located at %gs:40. Note that, on SMP, the boot cpu uses |
| * init data section till per cpu areas are set up. |
| */ |
| movl $MSR_GS_BASE,%ecx |
| movq initial_gs(%rip),%rax |
| movq %rax,%rdx |
| shrq $32,%rdx |
| wrmsr |
| |
| /* esi is pointer to real mode structure with interesting info. |
| pass it to C */ |
| movl %esi, %edi |
| |
| /* Finally jump to run C code and to be on real kernel address |
| * Since we are running on identity-mapped space we have to jump |
| * to the full 64bit address, this is only possible as indirect |
| * jump. In addition we need to ensure %cs is set so we make this |
| * a far return. |
| */ |
| movq initial_code(%rip),%rax |
| pushq $0 # fake return address to stop unwinder |
| pushq $__KERNEL_CS # set correct cs |
| pushq %rax # target address in negative space |
| lretq |
| |
| /* SMP bootup changes these two */ |
| __REFDATA |
| .align 8 |
| ENTRY(initial_code) |
| .quad x86_64_start_kernel |
| ENTRY(initial_gs) |
| .quad INIT_PER_CPU_VAR(irq_stack_union) |
| __FINITDATA |
| |
| ENTRY(stack_start) |
| .quad init_thread_union+THREAD_SIZE-8 |
| .word 0 |
| |
| bad_address: |
| jmp bad_address |
| |
| .section ".init.text","ax" |
| #ifdef CONFIG_EARLY_PRINTK |
| .globl early_idt_handlers |
| early_idt_handlers: |
| i = 0 |
| .rept NUM_EXCEPTION_VECTORS |
| movl $i, %esi |
| jmp early_idt_handler |
| i = i + 1 |
| .endr |
| #endif |
| |
| ENTRY(early_idt_handler) |
| #ifdef CONFIG_EARLY_PRINTK |
| cmpl $2,early_recursion_flag(%rip) |
| jz 1f |
| incl early_recursion_flag(%rip) |
| GET_CR2_INTO_RCX |
| movq %rcx,%r9 |
| xorl %r8d,%r8d # zero for error code |
| movl %esi,%ecx # get vector number |
| # Test %ecx against mask of vectors that push error code. |
| cmpl $31,%ecx |
| ja 0f |
| movl $1,%eax |
| salq %cl,%rax |
| testl $0x27d00,%eax |
| je 0f |
| popq %r8 # get error code |
| 0: movq 0(%rsp),%rcx # get ip |
| movq 8(%rsp),%rdx # get cs |
| xorl %eax,%eax |
| leaq early_idt_msg(%rip),%rdi |
| call early_printk |
| cmpl $2,early_recursion_flag(%rip) |
| jz 1f |
| call dump_stack |
| #ifdef CONFIG_KALLSYMS |
| leaq early_idt_ripmsg(%rip),%rdi |
| movq 0(%rsp),%rsi # get rip again |
| call __print_symbol |
| #endif |
| #endif /* EARLY_PRINTK */ |
| 1: hlt |
| jmp 1b |
| |
| #ifdef CONFIG_EARLY_PRINTK |
| early_recursion_flag: |
| .long 0 |
| |
| early_idt_msg: |
| .asciz "PANIC: early exception %02lx rip %lx:%lx error %lx cr2 %lx\n" |
| early_idt_ripmsg: |
| .asciz "RIP %s\n" |
| #endif /* CONFIG_EARLY_PRINTK */ |
| .previous |
| |
| #define NEXT_PAGE(name) \ |
| .balign PAGE_SIZE; \ |
| ENTRY(name) |
| |
| /* Automate the creation of 1 to 1 mapping pmd entries */ |
| #define PMDS(START, PERM, COUNT) \ |
| i = 0 ; \ |
| .rept (COUNT) ; \ |
| .quad (START) + (i << PMD_SHIFT) + (PERM) ; \ |
| i = i + 1 ; \ |
| .endr |
| |
| /* |
| * This default setting generates an ident mapping at address 0x100000 |
| * and a mapping for the kernel that precisely maps virtual address |
| * 0xffffffff80000000 to physical address 0x000000. (always using |
| * 2Mbyte large pages provided by PAE mode) |
| */ |
| NEXT_PAGE(init_level4_pgt) |
| .quad level3_ident_pgt - __START_KERNEL_map + _KERNPG_TABLE |
| .org init_level4_pgt + L4_PAGE_OFFSET*8, 0 |
| .quad level3_ident_pgt - __START_KERNEL_map + _KERNPG_TABLE |
| .org init_level4_pgt + L4_START_KERNEL*8, 0 |
| /* (2^48-(2*1024*1024*1024))/(2^39) = 511 */ |
| .quad level3_kernel_pgt - __START_KERNEL_map + _PAGE_TABLE |
| |
| NEXT_PAGE(level3_ident_pgt) |
| .quad level2_ident_pgt - __START_KERNEL_map + _KERNPG_TABLE |
| .fill 511,8,0 |
| |
| NEXT_PAGE(level3_kernel_pgt) |
| .fill L3_START_KERNEL,8,0 |
| /* (2^48-(2*1024*1024*1024)-((2^39)*511))/(2^30) = 510 */ |
| .quad level2_kernel_pgt - __START_KERNEL_map + _KERNPG_TABLE |
| .quad level2_fixmap_pgt - __START_KERNEL_map + _PAGE_TABLE |
| |
| NEXT_PAGE(level2_fixmap_pgt) |
| .fill 506,8,0 |
| .quad level1_fixmap_pgt - __START_KERNEL_map + _PAGE_TABLE |
| /* 8MB reserved for vsyscalls + a 2MB hole = 4 + 1 entries */ |
| .fill 5,8,0 |
| |
| NEXT_PAGE(level1_fixmap_pgt) |
| .fill 512,8,0 |
| |
| NEXT_PAGE(level2_ident_pgt) |
| /* Since I easily can, map the first 1G. |
| * Don't set NX because code runs from these pages. |
| */ |
| PMDS(0, __PAGE_KERNEL_IDENT_LARGE_EXEC, PTRS_PER_PMD) |
| |
| NEXT_PAGE(level2_kernel_pgt) |
| /* |
| * 512 MB kernel mapping. We spend a full page on this pagetable |
| * anyway. |
| * |
| * The kernel code+data+bss must not be bigger than that. |
| * |
| * (NOTE: at +512MB starts the module area, see MODULES_VADDR. |
| * If you want to increase this then increase MODULES_VADDR |
| * too.) |
| */ |
| PMDS(0, __PAGE_KERNEL_LARGE_EXEC, |
| KERNEL_IMAGE_SIZE/PMD_SIZE) |
| |
| NEXT_PAGE(level2_spare_pgt) |
| .fill 512, 8, 0 |
| |
| #undef PMDS |
| #undef NEXT_PAGE |
| |
| .data |
| .align 16 |
| .globl early_gdt_descr |
| early_gdt_descr: |
| .word GDT_ENTRIES*8-1 |
| early_gdt_descr_base: |
| .quad INIT_PER_CPU_VAR(gdt_page) |
| |
| ENTRY(phys_base) |
| /* This must match the first entry in level2_kernel_pgt */ |
| .quad 0x0000000000000000 |
| |
| #include "../../x86/xen/xen-head.S" |
| |
| .section .bss, "aw", @nobits |
| .align L1_CACHE_BYTES |
| ENTRY(idt_table) |
| .skip IDT_ENTRIES * 16 |
| |
| .section .bss.page_aligned, "aw", @nobits |
| .align PAGE_SIZE |
| ENTRY(empty_zero_page) |
| .skip PAGE_SIZE |
