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 = totalram_pages; 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 set_pmd(pmd, __pmd(_KERNPG_TABLE + 70 (unsigned long) __pa(pte))); 71 if (pte != pte_offset_kernel(pmd, 0)) 72 BUG(); 73 } 74 } 75 76 static void __init one_md_table_init(pud_t *pud) 77 { 78 #ifdef CONFIG_3_LEVEL_PGTABLES 79 pmd_t *pmd_table = (pmd_t *) memblock_alloc_low(PAGE_SIZE, PAGE_SIZE); 80 set_pud(pud, __pud(_KERNPG_TABLE + (unsigned long) __pa(pmd_table))); 81 if (pmd_table != pmd_offset(pud, 0)) 82 BUG(); 83 #endif 84 } 85 86 static void __init fixrange_init(unsigned long start, unsigned long end, 87 pgd_t *pgd_base) 88 { 89 pgd_t *pgd; 90 pud_t *pud; 91 pmd_t *pmd; 92 int i, j; 93 unsigned long vaddr; 94 95 vaddr = start; 96 i = pgd_index(vaddr); 97 j = pmd_index(vaddr); 98 pgd = pgd_base + i; 99 100 for ( ; (i < PTRS_PER_PGD) && (vaddr < end); pgd++, i++) { 101 pud = pud_offset(pgd, vaddr); 102 if (pud_none(*pud)) 103 one_md_table_init(pud); 104 pmd = pmd_offset(pud, vaddr); 105 for (; (j < PTRS_PER_PMD) && (vaddr < end); pmd++, j++) { 106 one_page_table_init(pmd); 107 vaddr += PMD_SIZE; 108 } 109 j = 0; 110 } 111 } 112 113 static void __init fixaddr_user_init( void) 114 { 115 #ifdef CONFIG_ARCH_REUSE_HOST_VSYSCALL_AREA 116 long size = FIXADDR_USER_END - FIXADDR_USER_START; 117 pgd_t *pgd; 118 pud_t *pud; 119 pmd_t *pmd; 120 pte_t *pte; 121 phys_t p; 122 unsigned long v, vaddr = FIXADDR_USER_START; 123 124 if (!size) 125 return; 126 127 fixrange_init( FIXADDR_USER_START, FIXADDR_USER_END, swapper_pg_dir); 128 v = (unsigned long) memblock_alloc_low(size, PAGE_SIZE); 129 memcpy((void *) v , (void *) FIXADDR_USER_START, size); 130 p = __pa(v); 131 for ( ; size > 0; size -= PAGE_SIZE, vaddr += PAGE_SIZE, 132 p += PAGE_SIZE) { 133 pgd = swapper_pg_dir + pgd_index(vaddr); 134 pud = pud_offset(pgd, vaddr); 135 pmd = pmd_offset(pud, vaddr); 136 pte = pte_offset_kernel(pmd, vaddr); 137 pte_set_val(*pte, p, PAGE_READONLY); 138 } 139 #endif 140 } 141 142 void __init paging_init(void) 143 { 144 unsigned long zones_size[MAX_NR_ZONES], vaddr; 145 int i; 146 147 empty_zero_page = (unsigned long *) memblock_alloc_low(PAGE_SIZE, 148 PAGE_SIZE); 149 for (i = 0; i < ARRAY_SIZE(zones_size); i++) 150 zones_size[i] = 0; 151 152 zones_size[ZONE_NORMAL] = (end_iomem >> PAGE_SHIFT) - 153 (uml_physmem >> PAGE_SHIFT); 154 free_area_init(zones_size); 155 156 /* 157 * Fixed mappings, only the page table structure has to be 158 * created - mappings will be set by set_fixmap(): 159 */ 160 vaddr = __fix_to_virt(__end_of_fixed_addresses - 1) & PMD_MASK; 161 fixrange_init(vaddr, FIXADDR_TOP, swapper_pg_dir); 162 163 fixaddr_user_init(); 164 } 165 166 /* 167 * This can't do anything because nothing in the kernel image can be freed 168 * since it's not in kernel physical memory. 169 */ 170 171 void free_initmem(void) 172 { 173 } 174 175 #ifdef CONFIG_BLK_DEV_INITRD 176 void free_initrd_mem(unsigned long start, unsigned long end) 177 { 178 free_reserved_area((void *)start, (void *)end, -1, "initrd"); 179 } 180 #endif 181 182 /* Allocate and free page tables. */ 183 184 pgd_t *pgd_alloc(struct mm_struct *mm) 185 { 186 pgd_t *pgd = (pgd_t *)__get_free_page(GFP_KERNEL); 187 188 if (pgd) { 189 memset(pgd, 0, USER_PTRS_PER_PGD * sizeof(pgd_t)); 190 memcpy(pgd + USER_PTRS_PER_PGD, 191 swapper_pg_dir + USER_PTRS_PER_PGD, 192 (PTRS_PER_PGD - USER_PTRS_PER_PGD) * sizeof(pgd_t)); 193 } 194 return pgd; 195 } 196 197 void pgd_free(struct mm_struct *mm, pgd_t *pgd) 198 { 199 free_page((unsigned long) pgd); 200 } 201 202 pte_t *pte_alloc_one_kernel(struct mm_struct *mm, unsigned long address) 203 { 204 pte_t *pte; 205 206 pte = (pte_t *)__get_free_page(GFP_KERNEL|__GFP_ZERO); 207 return pte; 208 } 209 210 pgtable_t pte_alloc_one(struct mm_struct *mm, unsigned long address) 211 { 212 struct page *pte; 213 214 pte = alloc_page(GFP_KERNEL|__GFP_ZERO); 215 if (!pte) 216 return NULL; 217 if (!pgtable_page_ctor(pte)) { 218 __free_page(pte); 219 return NULL; 220 } 221 return pte; 222 } 223 224 #ifdef CONFIG_3_LEVEL_PGTABLES 225 pmd_t *pmd_alloc_one(struct mm_struct *mm, unsigned long address) 226 { 227 pmd_t *pmd = (pmd_t *) __get_free_page(GFP_KERNEL); 228 229 if (pmd) 230 memset(pmd, 0, PAGE_SIZE); 231 232 return pmd; 233 } 234 #endif 235 236 void *uml_kmalloc(int size, int flags) 237 { 238 return kmalloc(size, flags); 239 } 240