diff options
Diffstat (limited to 'arch/x86_64/kernel/head.S')
| -rw-r--r-- | arch/x86_64/kernel/head.S | 340 |
1 files changed, 169 insertions, 171 deletions
diff --git a/arch/x86_64/kernel/head.S b/arch/x86_64/kernel/head.S index 598a4d0351f..1fab487dee8 100644 --- a/arch/x86_64/kernel/head.S +++ b/arch/x86_64/kernel/head.S @@ -5,6 +5,7 @@ * 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> */ @@ -13,97 +14,131 @@ #include <linux/init.h> #include <asm/desc.h> #include <asm/segment.h> +#include <asm/pgtable.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 - * + * because we need identity-mapped pages. + * */ .text .section .bootstrap.text - .code32 - .globl startup_32 -/* %bx: 1 if coming from smp trampoline on secondary cpu */ -startup_32: - + .code64 + .globl startup_64 +startup_64: + /* - * 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. + * 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. */ - /* 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. + /* Compute the delta between the address I am compiled to run at and the + * address I am actually running at. */ - - /* 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 + leaq _text(%rip), %rbp + subq $_text - __START_KERNEL_map, %rbp + + /* Is the address not 2M aligned? */ + movq %rbp, %rax + andl $~LARGE_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 + (258*8)(%rip) + addq %rbp, init_level4_pgt + (511*8)(%rip) + + addq %rbp, level3_ident_pgt + 0(%rip) + addq %rbp, level3_kernel_pgt + (510*8)(%rip) + + /* Add an Identity mapping if I am above 1G */ + leaq _text(%rip), %rdi + andq $LARGE_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_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 + */ + 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) - /* Enable PAE mode */ - xorl %eax, %eax - btsl $5, %eax - movl %eax, %cr4 - - /* Setup early boot stage 4 level pagetables */ - movl $(boot_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 +#ifdef CONFIG_SMP + addq %rbp, trampoline_level4_pgt + 0(%rip) + addq %rbp, trampoline_level4_pgt + (511*8)(%rip) +#endif +#ifdef CONFIG_ACPI_SLEEP + addq %rbp, wakeup_level4_pgt + 0(%rip) + addq %rbp, wakeup_level4_pgt + (511*8)(%rip) +#endif - 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. + /* 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) */ - 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. + 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 */ @@ -113,9 +148,15 @@ startup_64: movq %rax, %cr4 /* Setup early boot stage 4 level pagetables. */ - movq $(boot_level4_pgt - __START_KERNEL_map), %rax + 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 @@ -124,17 +165,11 @@ startup_64: /* Setup EFER (Extended Feature Enable Register) */ movl $MSR_EFER, %ecx rdmsr - - /* Enable System Call */ - btsl $_EFER_SCE, %eax - - /* No Execute supported? */ - btl $20,%edi + btsl $_EFER_SCE, %eax /* Enable System Call */ + btl $20,%edi /* No Execute supported? */ jnc 1f btsl $_EFER_NX, %eax -1: - /* Make changes effective */ - wrmsr +1: wrmsr /* Make changes effective */ /* Setup cr0 */ #define CR0_PM 1 /* protected mode */ @@ -161,7 +196,7 @@ startup_64: * 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 + lgdt cpu_gdt_descr(%rip) /* set up data segments. actually 0 would do too */ movl $__KERNEL_DS,%eax @@ -212,6 +247,9 @@ initial_code: init_rsp: .quad init_thread_union+THREAD_SIZE-8 +bad_address: + jmp bad_address + ENTRY(early_idt_handler) cmpl $2,early_recursion_flag(%rip) jz 1f @@ -240,110 +278,66 @@ early_idt_msg: early_idt_ripmsg: .asciz "RIP %s\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-1 - .long cpu_gdt_table-__START_KERNEL_map - -.org 0xf10 -ljumpvector: - .long startup_64-__START_KERNEL_map - .word __KERNEL_CS +.balign PAGE_SIZE -ENTRY(stext) -ENTRY(_stext) - - $page = 0 #define NEXT_PAGE(name) \ - $page = $page + 1; \ - .org $page * 0x1000; \ - phys_/**/name = $page * 0x1000 + __PHYSICAL_START; \ + .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 << 21) + (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) - /* This gets initialized in x86_64_start_kernel */ - .fill 512,8,0 + .quad level3_ident_pgt - __START_KERNEL_map + _KERNPG_TABLE + .fill 257,8,0 + .quad level3_ident_pgt - __START_KERNEL_map + _KERNPG_TABLE + .fill 252,8,0 + /* (2^48-(2*1024*1024*1024))/(2^39) = 511 */ + .quad level3_kernel_pgt - __START_KERNEL_map + _PAGE_TABLE NEXT_PAGE(level3_ident_pgt) - .quad phys_level2_ident_pgt | 0x007 + .quad level2_ident_pgt - __START_KERNEL_map + _KERNPG_TABLE .fill 511,8,0 NEXT_PAGE(level3_kernel_pgt) .fill 510,8,0 /* (2^48-(2*1024*1024*1024)-((2^39)*511))/(2^30) = 510 */ - .quad phys_level2_kernel_pgt | 0x007 + .quad level2_kernel_pgt - __START_KERNEL_map + _KERNPG_TABLE .fill 1,8,0 NEXT_PAGE(level2_ident_pgt) - /* 40MB for bootup. */ - i = 0 - .rept 20 - .quad i << 21 | 0x083 - i = i + 1 - .endr - /* 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 - + /* Since I easily can, map the first 1G. + * Don't set NX because code runs from these pages. + */ + PMDS(0x0000000000000000, __PAGE_KERNEL_LARGE_EXEC, PTRS_PER_PMD) + NEXT_PAGE(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 */ - i = 0 - .rept 20 - .quad i << 21 | 0x183 - i = i + 1 - .endr + PMDS(0x0000000000000000, __PAGE_KERNEL_LARGE_EXEC|_PAGE_GLOBAL, + KERNEL_TEXT_SIZE/PMD_SIZE) /* Module mapping starts here */ - .fill 492,8,0 + .fill (PTRS_PER_PMD - (KERNEL_TEXT_SIZE/PMD_SIZE)),8,0 -NEXT_PAGE(level3_physmem_pgt) - .quad phys_level2_kernel_pgt | 0x007 /* so that __va works even before pagetable_init */ - .fill 511,8,0 +NEXT_PAGE(level2_spare_pgt) + .fill 512,8,0 +#undef PMDS #undef NEXT_PAGE .data - -#ifdef CONFIG_ACPI_SLEEP - .align PAGE_SIZE -ENTRY(wakeup_level4_pgt) - .quad phys_level3_ident_pgt | 0x007 - .fill 255,8,0 - .quad phys_level3_physmem_pgt | 0x007 - .fill 254,8,0 - /* (2^48-(2*1024*1024*1024))/(2^39) = 511 */ - .quad phys_level3_kernel_pgt | 0x007 -#endif - -#ifndef CONFIG_HOTPLUG_CPU - __INITDATA -#endif - /* - * 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) - */ - .align PAGE_SIZE -ENTRY(boot_level4_pgt) - .quad phys_level3_ident_pgt | 0x007 - .fill 255,8,0 - .quad phys_level3_physmem_pgt | 0x007 - .fill 254,8,0 - /* (2^48-(2*1024*1024*1024))/(2^39) = 511 */ - .quad phys_level3_kernel_pgt | 0x007 - - .data - .align 16 .globl cpu_gdt_descr cpu_gdt_descr: @@ -357,6 +351,10 @@ gdt: .endr #endif +ENTRY(phys_base) + /* This must match the first entry in level2_kernel_pgt */ + .quad 0x0000000000000000 + /* 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 @@ -370,13 +368,13 @@ gdt: ENTRY(cpu_gdt_table) .quad 0x0000000000000000 /* NULL descriptor */ + .quad 0x00cf9b000000ffff /* __KERNEL32_CS */ + .quad 0x00af9b000000ffff /* __KERNEL_CS */ + .quad 0x00cf93000000ffff /* __KERNEL_DS */ + .quad 0x00cffb000000ffff /* __USER32_CS */ + .quad 0x00cff3000000ffff /* __USER_DS, __USER32_DS */ + .quad 0x00affb000000ffff /* __USER_CS */ .quad 0x0 /* unused */ - .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 */ |