1 /* 2 * linux/arch/i386/kernel/head32.c -- prepare to run common code 3 * 4 * Copyright (C) 2000 Andrea Arcangeli <andrea@suse.de> SuSE 5 * Copyright (C) 2007 Eric Biederman <ebiederm@xmission.com> 6 */ 7 8 #include <linux/init.h> 9 #include <linux/start_kernel.h> 10 #include <linux/mm.h> 11 #include <linux/memblock.h> 12 13 #include <asm/setup.h> 14 #include <asm/sections.h> 15 #include <asm/e820/api.h> 16 #include <asm/page.h> 17 #include <asm/apic.h> 18 #include <asm/io_apic.h> 19 #include <asm/bios_ebda.h> 20 #include <asm/tlbflush.h> 21 #include <asm/bootparam_utils.h> 22 23 static void __init i386_default_early_setup(void) 24 { 25 /* Initialize 32bit specific setup functions */ 26 x86_init.resources.reserve_resources = i386_reserve_resources; 27 x86_init.mpparse.setup_ioapic_ids = setup_ioapic_ids_from_mpc; 28 } 29 30 asmlinkage __visible void __init i386_start_kernel(void) 31 { 32 cr4_init_shadow(); 33 sanitize_boot_params(&boot_params); 34 35 x86_early_init_platform_quirks(); 36 37 /* Call the subarch specific early setup function */ 38 switch (boot_params.hdr.hardware_subarch) { 39 case X86_SUBARCH_INTEL_MID: 40 x86_intel_mid_early_setup(); 41 break; 42 case X86_SUBARCH_CE4100: 43 x86_ce4100_early_setup(); 44 break; 45 default: 46 i386_default_early_setup(); 47 break; 48 } 49 50 start_kernel(); 51 } 52 53 /* 54 * Initialize page tables. This creates a PDE and a set of page 55 * tables, which are located immediately beyond __brk_base. The variable 56 * _brk_end is set up to point to the first "safe" location. 57 * Mappings are created both at virtual address 0 (identity mapping) 58 * and PAGE_OFFSET for up to _end. 59 * 60 * In PAE mode initial_page_table is statically defined to contain 61 * enough entries to cover the VMSPLIT option (that is the top 1, 2 or 3 62 * entries). The identity mapping is handled by pointing two PGD entries 63 * to the first kernel PMD. Note the upper half of each PMD or PTE are 64 * always zero at this stage. 65 */ 66 void __init mk_early_pgtbl_32(void) 67 { 68 #ifdef __pa 69 #undef __pa 70 #endif 71 #define __pa(x) ((unsigned long)(x) - PAGE_OFFSET) 72 pte_t pte, *ptep; 73 int i; 74 unsigned long *ptr; 75 /* Enough space to fit pagetables for the low memory linear map */ 76 const unsigned long limit = __pa(_end) + 77 (PAGE_TABLE_SIZE(LOWMEM_PAGES) << PAGE_SHIFT); 78 #ifdef CONFIG_X86_PAE 79 pmd_t pl2, *pl2p = (pmd_t *)__pa(initial_pg_pmd); 80 #define SET_PL2(pl2, val) { (pl2).pmd = (val); } 81 #else 82 pgd_t pl2, *pl2p = (pgd_t *)__pa(initial_page_table); 83 #define SET_PL2(pl2, val) { (pl2).pgd = (val); } 84 #endif 85 86 ptep = (pte_t *)__pa(__brk_base); 87 pte.pte = PTE_IDENT_ATTR; 88 89 while ((pte.pte & PTE_PFN_MASK) < limit) { 90 91 SET_PL2(pl2, (unsigned long)ptep | PDE_IDENT_ATTR); 92 *pl2p = pl2; 93 #ifndef CONFIG_X86_PAE 94 /* Kernel PDE entry */ 95 *(pl2p + ((PAGE_OFFSET >> PGDIR_SHIFT))) = pl2; 96 #endif 97 for (i = 0; i < PTRS_PER_PTE; i++) { 98 *ptep = pte; 99 pte.pte += PAGE_SIZE; 100 ptep++; 101 } 102 103 pl2p++; 104 } 105 106 ptr = (unsigned long *)__pa(&max_pfn_mapped); 107 /* Can't use pte_pfn() since it's a call with CONFIG_PARAVIRT */ 108 *ptr = (pte.pte & PTE_PFN_MASK) >> PAGE_SHIFT; 109 110 ptr = (unsigned long *)__pa(&_brk_end); 111 *ptr = (unsigned long)ptep + PAGE_OFFSET; 112 } 113 114