1 /* 2 * Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com) 3 * Licensed under the GPL 4 */ 5 6 #include <linux/stddef.h> 7 #include <linux/module.h> 8 #include <linux/memblock.h> 9 #include <linux/highmem.h> 10 #include <linux/mm.h> 11 #include <linux/swap.h> 12 #include <linux/slab.h> 13 #include <asm/fixmap.h> 14 #include <asm/page.h> 15 #include <as-layout.h> 16 #include <init.h> 17 #include <kern.h> 18 #include <kern_util.h> 19 #include <mem_user.h> 20 #include <os.h> 21 22 /* allocated in paging_init, zeroed in mem_init, and unchanged thereafter */ 23 unsigned long *empty_zero_page = NULL; 24 EXPORT_SYMBOL(empty_zero_page); 25 26 /* 27 * Initialized during boot, and readonly for initializing page tables 28 * afterwards 29 */ 30 pgd_t swapper_pg_dir[PTRS_PER_PGD]; 31 32 /* Initialized at boot time, and readonly after that */ 33 unsigned long long highmem; 34 int kmalloc_ok = 0; 35 36 /* Used during early boot */ 37 static unsigned long brk_end; 38 39 void __init mem_init(void) 40 { 41 /* clear the zero-page */ 42 memset(empty_zero_page, 0, PAGE_SIZE); 43 44 /* Map in the area just after the brk now that kmalloc is about 45 * to be turned on. 46 */ 47 brk_end = (unsigned long) UML_ROUND_UP(sbrk(0)); 48 map_memory(brk_end, __pa(brk_end), uml_reserved - brk_end, 1, 1, 0); 49 memblock_free(__pa(brk_end), uml_reserved - brk_end); 50 uml_reserved = brk_end; 51 52 /* this will put all low memory onto the freelists */ 53 memblock_free_all(); 54 max_low_pfn = totalram_pages(); 55 max_pfn = max_low_pfn; 56 mem_init_print_info(NULL); 57 kmalloc_ok = 1; 58 } 59 60 /* 61 * Create a page table and place a pointer to it in a middle page 62 * directory entry. 63 */ 64 static void __init one_page_table_init(pmd_t *pmd) 65 { 66 if (pmd_none(*pmd)) { 67 pte_t *pte = (pte_t *) memblock_alloc_low(PAGE_SIZE, 68 PAGE_SIZE); 69 if (!pte) 70 panic("%s: Failed to allocate %lu bytes align=%lx\n", 71 __func__, PAGE_SIZE, PAGE_SIZE); 72 73 set_pmd(pmd, __pmd(_KERNPG_TABLE + 74 (unsigned long) __pa(pte))); 75 if (pte != pte_offset_kernel(pmd, 0)) 76 BUG(); 77 } 78 } 79 80 static void __init one_md_table_init(pud_t *pud) 81 { 82 #ifdef CONFIG_3_LEVEL_PGTABLES 83 pmd_t *pmd_table = (pmd_t *) memblock_alloc_low(PAGE_SIZE, PAGE_SIZE); 84 if (!pmd_table) 85 panic("%s: Failed to allocate %lu bytes align=%lx\n", 86 __func__, PAGE_SIZE, PAGE_SIZE); 87 88 set_pud(pud, __pud(_KERNPG_TABLE + (unsigned long) __pa(pmd_table))); 89 if (pmd_table != pmd_offset(pud, 0)) 90 BUG(); 91 #endif 92 } 93 94 static void __init fixrange_init(unsigned long start, unsigned long end, 95 pgd_t *pgd_base) 96 { 97 pgd_t *pgd; 98 pud_t *pud; 99 pmd_t *pmd; 100 int i, j; 101 unsigned long vaddr; 102 103 vaddr = start; 104 i = pgd_index(vaddr); 105 j = pmd_index(vaddr); 106 pgd = pgd_base + i; 107 108 for ( ; (i < PTRS_PER_PGD) && (vaddr < end); pgd++, i++) { 109 pud = pud_offset(pgd, vaddr); 110 if (pud_none(*pud)) 111 one_md_table_init(pud); 112 pmd = pmd_offset(pud, vaddr); 113 for (; (j < PTRS_PER_PMD) && (vaddr < end); pmd++, j++) { 114 one_page_table_init(pmd); 115 vaddr += PMD_SIZE; 116 } 117 j = 0; 118 } 119 } 120 121 static void __init fixaddr_user_init( void) 122 { 123 #ifdef CONFIG_ARCH_REUSE_HOST_VSYSCALL_AREA 124 long size = FIXADDR_USER_END - FIXADDR_USER_START; 125 pgd_t *pgd; 126 pud_t *pud; 127 pmd_t *pmd; 128 pte_t *pte; 129 phys_t p; 130 unsigned long v, vaddr = FIXADDR_USER_START; 131 132 if (!size) 133 return; 134 135 fixrange_init( FIXADDR_USER_START, FIXADDR_USER_END, swapper_pg_dir); 136 v = (unsigned long) memblock_alloc_low(size, PAGE_SIZE); 137 if (!v) 138 panic("%s: Failed to allocate %lu bytes align=%lx\n", 139 __func__, size, PAGE_SIZE); 140 141 memcpy((void *) v , (void *) FIXADDR_USER_START, size); 142 p = __pa(v); 143 for ( ; size > 0; size -= PAGE_SIZE, vaddr += PAGE_SIZE, 144 p += PAGE_SIZE) { 145 pgd = swapper_pg_dir + pgd_index(vaddr); 146 pud = pud_offset(pgd, vaddr); 147 pmd = pmd_offset(pud, vaddr); 148 pte = pte_offset_kernel(pmd, vaddr); 149 pte_set_val(*pte, p, PAGE_READONLY); 150 } 151 #endif 152 } 153 154 void __init paging_init(void) 155 { 156 unsigned long zones_size[MAX_NR_ZONES], vaddr; 157 int i; 158 159 empty_zero_page = (unsigned long *) memblock_alloc_low(PAGE_SIZE, 160 PAGE_SIZE); 161 if (!empty_zero_page) 162 panic("%s: Failed to allocate %lu bytes align=%lx\n", 163 __func__, PAGE_SIZE, PAGE_SIZE); 164 165 for (i = 0; i < ARRAY_SIZE(zones_size); i++) 166 zones_size[i] = 0; 167 168 zones_size[ZONE_NORMAL] = (end_iomem >> PAGE_SHIFT) - 169 (uml_physmem >> PAGE_SHIFT); 170 free_area_init(zones_size); 171 172 /* 173 * Fixed mappings, only the page table structure has to be 174 * created - mappings will be set by set_fixmap(): 175 */ 176 vaddr = __fix_to_virt(__end_of_fixed_addresses - 1) & PMD_MASK; 177 fixrange_init(vaddr, FIXADDR_TOP, swapper_pg_dir); 178 179 fixaddr_user_init(); 180 } 181 182 /* 183 * This can't do anything because nothing in the kernel image can be freed 184 * since it's not in kernel physical memory. 185 */ 186 187 void free_initmem(void) 188 { 189 } 190 191 /* Allocate and free page tables. */ 192 193 pgd_t *pgd_alloc(struct mm_struct *mm) 194 { 195 pgd_t *pgd = (pgd_t *)__get_free_page(GFP_KERNEL); 196 197 if (pgd) { 198 memset(pgd, 0, USER_PTRS_PER_PGD * sizeof(pgd_t)); 199 memcpy(pgd + USER_PTRS_PER_PGD, 200 swapper_pg_dir + USER_PTRS_PER_PGD, 201 (PTRS_PER_PGD - USER_PTRS_PER_PGD) * sizeof(pgd_t)); 202 } 203 return pgd; 204 } 205 206 void pgd_free(struct mm_struct *mm, pgd_t *pgd) 207 { 208 free_page((unsigned long) pgd); 209 } 210 211 #ifdef CONFIG_3_LEVEL_PGTABLES 212 pmd_t *pmd_alloc_one(struct mm_struct *mm, unsigned long address) 213 { 214 pmd_t *pmd = (pmd_t *) __get_free_page(GFP_KERNEL); 215 216 if (pmd) 217 memset(pmd, 0, PAGE_SIZE); 218 219 return pmd; 220 } 221 #endif 222 223 void *uml_kmalloc(int size, int flags) 224 { 225 return kmalloc(size, flags); 226 } 227