diff options
Diffstat (limited to 'arch/x86_64/kernel/head.S')
| -rw-r--r-- | arch/x86_64/kernel/head.S | 396 |
1 files changed, 396 insertions, 0 deletions
diff --git a/arch/x86_64/kernel/head.S b/arch/x86_64/kernel/head.S new file mode 100644 index 00000000000..b6d8725c1f6 --- /dev/null +++ b/arch/x86_64/kernel/head.S @@ -0,0 +1,396 @@ +/* + * 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> + * + * $Id: head.S,v 1.49 2002/03/19 17:39:25 ak Exp $ + */ + + +#include <linux/linkage.h> +#include <linux/threads.h> +#include <asm/desc.h> +#include <asm/segment.h> +#include <asm/page.h> +#include <asm/msr.h> +#include <asm/cache.h> + +/* we are not able to switch in one step to the final KERNEL ADRESS SPACE + * because we need identity-mapped pages on setup so define __START_KERNEL to + * 0x100000 for this stage + * + */ + + .text + .code32 + .globl startup_32 +/* %bx: 1 if coming from smp trampoline on secondary cpu */ +startup_32: + + /* + * At this point the CPU runs in 32bit protected mode (CS.D = 1) with + * paging disabled and the point of this file is to switch to 64bit + * long mode with a kernel mapping for kerneland to jump into the + * kernel virtual addresses. + * There is no stack until we set one up. + */ + + /* Initialize the %ds segment register */ + movl $__KERNEL_DS,%eax + movl %eax,%ds + + /* Load new GDT with the 64bit segments using 32bit descriptor */ + lgdt pGDT32 - __START_KERNEL_map + + /* If the CPU doesn't support CPUID this will double fault. + * Unfortunately it is hard to check for CPUID without a stack. + */ + + /* Check if extended functions are implemented */ + movl $0x80000000, %eax + cpuid + cmpl $0x80000000, %eax + jbe no_long_mode + /* Check if long mode is implemented */ + mov $0x80000001, %eax + cpuid + btl $29, %edx + jnc no_long_mode + + /* + * Prepare for entering 64bits mode + */ + + /* Enable PAE mode */ + xorl %eax, %eax + btsl $5, %eax + movl %eax, %cr4 + + /* Setup early boot stage 4 level pagetables */ + movl $(init_level4_pgt - __START_KERNEL_map), %eax + movl %eax, %cr3 + + /* Setup EFER (Extended Feature Enable Register) */ + movl $MSR_EFER, %ecx + rdmsr + + /* Enable Long Mode */ + btsl $_EFER_LME, %eax + + /* Make changes effective */ + wrmsr + + xorl %eax, %eax + btsl $31, %eax /* Enable paging and in turn activate Long Mode */ + btsl $0, %eax /* Enable protected mode */ + /* Make changes effective */ + movl %eax, %cr0 + /* + * At this point we're in long mode but in 32bit compatibility mode + * with EFER.LME = 1, CS.L = 0, CS.D = 1 (and in turn + * EFER.LMA = 1). Now we want to jump in 64bit mode, to do that we use + * the new gdt/idt that has __KERNEL_CS with CS.L = 1. + */ + ljmp $__KERNEL_CS, $(startup_64 - __START_KERNEL_map) + + .code64 + .org 0x100 + .globl startup_64 +startup_64: + /* We come here either from startup_32 + * or directly from a 64bit bootloader. + * Since we may have come directly from a bootloader we + * reload the page tables here. + */ + + /* Enable PAE mode and PGE */ + xorq %rax, %rax + btsq $5, %rax + btsq $7, %rax + movq %rax, %cr4 + + /* Setup early boot stage 4 level pagetables. */ + movq $(init_level4_pgt - __START_KERNEL_map), %rax + movq %rax, %cr3 + + /* Check if nx is implemented */ + movl $0x80000001, %eax + cpuid + movl %edx,%edi + + /* Setup EFER (Extended Feature Enable Register) */ + movl $MSR_EFER, %ecx + rdmsr + + /* Enable System Call */ + btsl $_EFER_SCE, %eax + + /* No Execute supported? */ + btl $20,%edi + jnc 1f + btsl $_EFER_NX, %eax +1: + /* Make changes effective */ + wrmsr + + /* Setup cr0 */ + xorq %rax, %rax + btsq $31, %rax /* Enable paging */ + btsq $0, %rax /* Enable protected mode */ + btsq $1, %rax /* Enable MP */ + btsq $4, %rax /* Enable ET */ + btsq $5, %rax /* Enable NE */ + btsq $16, %rax /* Enable WP */ + btsq $18, %rax /* Enable AM */ + /* Make changes effective */ + movq %rax, %cr0 + + /* Setup a boot time stack */ + movq init_rsp(%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 cpu_gdt_descr + + /* + * Setup up a dummy PDA. this is just for some early bootup code + * that does in_interrupt() + */ + movl $MSR_GS_BASE,%ecx + movq $empty_zero_page,%rax + movq %rax,%rdx + shrq $32,%rdx + wrmsr + + /* set up data segments. actually 0 would do too */ + movl $__KERNEL_DS,%eax + movl %eax,%ds + movl %eax,%ss + movl %eax,%es + + /* 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 + */ + movq initial_code(%rip),%rax + jmp *%rax + + /* SMP bootup changes these two */ + .globl initial_code +initial_code: + .quad x86_64_start_kernel + .globl init_rsp +init_rsp: + .quad init_thread_union+THREAD_SIZE-8 + +ENTRY(early_idt_handler) + xorl %eax,%eax + movq 8(%rsp),%rsi # get rip + movq (%rsp),%rdx + movq %cr2,%rcx + leaq early_idt_msg(%rip),%rdi + call early_printk +1: hlt + jmp 1b + +early_idt_msg: + .asciz "PANIC: early exception rip %lx error %lx cr2 %lx\n" + +.code32 +ENTRY(no_long_mode) + /* This isn't an x86-64 CPU so hang */ +1: + jmp 1b + +.org 0xf00 + .globl pGDT32 +pGDT32: + .word gdt_end-cpu_gdt_table + .long cpu_gdt_table-__START_KERNEL_map + +.org 0xf10 +ljumpvector: + .long startup_64-__START_KERNEL_map + .word __KERNEL_CS + +ENTRY(stext) +ENTRY(_stext) + + /* + * 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) + */ +.org 0x1000 +ENTRY(init_level4_pgt) + .quad 0x0000000000102007 /* -> level3_ident_pgt */ + .fill 255,8,0 + .quad 0x000000000010a007 + .fill 254,8,0 + /* (2^48-(2*1024*1024*1024))/(2^39) = 511 */ + .quad 0x0000000000103007 /* -> level3_kernel_pgt */ + +.org 0x2000 +ENTRY(level3_ident_pgt) + .quad 0x0000000000104007 + .fill 511,8,0 + +.org 0x3000 +ENTRY(level3_kernel_pgt) + .fill 510,8,0 + /* (2^48-(2*1024*1024*1024)-((2^39)*511))/(2^30) = 510 */ + .quad 0x0000000000105007 /* -> level2_kernel_pgt */ + .fill 1,8,0 + +.org 0x4000 +ENTRY(level2_ident_pgt) + /* 40MB for bootup. */ + .quad 0x0000000000000283 + .quad 0x0000000000200183 + .quad 0x0000000000400183 + .quad 0x0000000000600183 + .quad 0x0000000000800183 + .quad 0x0000000000A00183 + .quad 0x0000000000C00183 + .quad 0x0000000000E00183 + .quad 0x0000000001000183 + .quad 0x0000000001200183 + .quad 0x0000000001400183 + .quad 0x0000000001600183 + .quad 0x0000000001800183 + .quad 0x0000000001A00183 + .quad 0x0000000001C00183 + .quad 0x0000000001E00183 + .quad 0x0000000002000183 + .quad 0x0000000002200183 + .quad 0x0000000002400183 + .quad 0x0000000002600183 + /* Temporary mappings for the super early allocator in arch/x86_64/mm/init.c */ + .globl temp_boot_pmds +temp_boot_pmds: + .fill 492,8,0 + +.org 0x5000 +ENTRY(level2_kernel_pgt) + /* 40MB kernel mapping. The kernel code cannot be bigger than that. + When you change this change KERNEL_TEXT_SIZE in page.h too. */ + /* (2^48-(2*1024*1024*1024)-((2^39)*511)-((2^30)*510)) = 0 */ + .quad 0x0000000000000183 + .quad 0x0000000000200183 + .quad 0x0000000000400183 + .quad 0x0000000000600183 + .quad 0x0000000000800183 + .quad 0x0000000000A00183 + .quad 0x0000000000C00183 + .quad 0x0000000000E00183 + .quad 0x0000000001000183 + .quad 0x0000000001200183 + .quad 0x0000000001400183 + .quad 0x0000000001600183 + .quad 0x0000000001800183 + .quad 0x0000000001A00183 + .quad 0x0000000001C00183 + .quad 0x0000000001E00183 + .quad 0x0000000002000183 + .quad 0x0000000002200183 + .quad 0x0000000002400183 + .quad 0x0000000002600183 + /* Module mapping starts here */ + .fill 492,8,0 + +.org 0x6000 +ENTRY(empty_zero_page) + +.org 0x7000 +ENTRY(empty_bad_page) + +.org 0x8000 +ENTRY(empty_bad_pte_table) + +.org 0x9000 +ENTRY(empty_bad_pmd_table) + +.org 0xa000 +ENTRY(level3_physmem_pgt) + .quad 0x0000000000105007 /* -> level2_kernel_pgt (so that __va works even before pagetable_init) */ + + .org 0xb000 +#ifdef CONFIG_ACPI_SLEEP +ENTRY(wakeup_level4_pgt) + .quad 0x0000000000102007 /* -> level3_ident_pgt */ + .fill 255,8,0 + .quad 0x000000000010a007 + .fill 254,8,0 + /* (2^48-(2*1024*1024*1024))/(2^39) = 511 */ + .quad 0x0000000000103007 /* -> level3_kernel_pgt */ +#endif + + .data + + .align 16 + .globl cpu_gdt_descr +cpu_gdt_descr: + .word gdt_end-cpu_gdt_table +gdt: + .quad cpu_gdt_table +#ifdef CONFIG_SMP + .rept NR_CPUS-1 + .word 0 + .quad 0 + .endr +#endif + +/* We need valid kernel segments for data and code in long mode too + * IRET will check the segment types kkeil 2000/10/28 + * Also sysret mandates a special GDT layout + */ + +.align L1_CACHE_BYTES + +/* The TLS descriptors are currently at a different place compared to i386. + Hopefully nobody expects them at a fixed place (Wine?) */ + +ENTRY(cpu_gdt_table) + .quad 0x0000000000000000 /* NULL descriptor */ + .quad 0x008f9a000000ffff /* __KERNEL_COMPAT32_CS */ + .quad 0x00af9a000000ffff /* __KERNEL_CS */ + .quad 0x00cf92000000ffff /* __KERNEL_DS */ + .quad 0x00cffa000000ffff /* __USER32_CS */ + .quad 0x00cff2000000ffff /* __USER_DS, __USER32_DS */ + .quad 0x00affa000000ffff /* __USER_CS */ + .quad 0x00cf9a000000ffff /* __KERNEL32_CS */ + .quad 0,0 /* TSS */ + .quad 0,0 /* LDT */ + .quad 0,0,0 /* three TLS descriptors */ + .quad 0x00009a000000ffff /* __KERNEL16_CS - 16bit PM for S3 wakeup. */ + /* base must be patched for real base address. */ +gdt_end: + /* asm/segment.h:GDT_ENTRIES must match this */ + /* This should be a multiple of the cache line size */ + /* GDTs of other CPUs: */ + .fill (GDT_SIZE * NR_CPUS) - (gdt_end - cpu_gdt_table) + + .align L1_CACHE_BYTES +ENTRY(idt_table) + .rept 256 + .quad 0 + .quad 0 + .endr + |