1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com) 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 #include <linux/sched/task.h> 22 23 #ifdef CONFIG_KASAN 24 int kasan_um_is_ready; 25 void kasan_init(void) 26 { 27 /* 28 * kasan_map_memory will map all of the required address space and 29 * the host machine will allocate physical memory as necessary. 30 */ 31 kasan_map_memory((void *)KASAN_SHADOW_START, KASAN_SHADOW_SIZE); 32 init_task.kasan_depth = 0; 33 kasan_um_is_ready = true; 34 } 35 36 static void (*kasan_init_ptr)(void) 37 __section(".kasan_init") __used 38 = kasan_init; 39 #endif 40 41 /* allocated in paging_init, zeroed in mem_init, and unchanged thereafter */ 42 unsigned long *empty_zero_page = NULL; 43 EXPORT_SYMBOL(empty_zero_page); 44 45 /* 46 * Initialized during boot, and readonly for initializing page tables 47 * afterwards 48 */ 49 pgd_t swapper_pg_dir[PTRS_PER_PGD]; 50 51 /* Initialized at boot time, and readonly after that */ 52 unsigned long long highmem; 53 EXPORT_SYMBOL(highmem); 54 int kmalloc_ok = 0; 55 56 /* Used during early boot */ 57 static unsigned long brk_end; 58 59 void __init mem_init(void) 60 { 61 /* clear the zero-page */ 62 memset(empty_zero_page, 0, PAGE_SIZE); 63 64 /* Map in the area just after the brk now that kmalloc is about 65 * to be turned on. 66 */ 67 brk_end = (unsigned long) UML_ROUND_UP(sbrk(0)); 68 map_memory(brk_end, __pa(brk_end), uml_reserved - brk_end, 1, 1, 0); 69 memblock_free((void *)brk_end, uml_reserved - brk_end); 70 uml_reserved = brk_end; 71 72 /* this will put all low memory onto the freelists */ 73 memblock_free_all(); 74 max_low_pfn = totalram_pages(); 75 max_pfn = max_low_pfn; 76 kmalloc_ok = 1; 77 } 78 79 /* 80 * Create a page table and place a pointer to it in a middle page 81 * directory entry. 82 */ 83 static void __init one_page_table_init(pmd_t *pmd) 84 { 85 if (pmd_none(*pmd)) { 86 pte_t *pte = (pte_t *) memblock_alloc_low(PAGE_SIZE, 87 PAGE_SIZE); 88 if (!pte) 89 panic("%s: Failed to allocate %lu bytes align=%lx\n", 90 __func__, PAGE_SIZE, PAGE_SIZE); 91 92 set_pmd(pmd, __pmd(_KERNPG_TABLE + 93 (unsigned long) __pa(pte))); 94 BUG_ON(pte != pte_offset_kernel(pmd, 0)); 95 } 96 } 97 98 static void __init one_md_table_init(pud_t *pud) 99 { 100 #ifdef CONFIG_3_LEVEL_PGTABLES 101 pmd_t *pmd_table = (pmd_t *) memblock_alloc_low(PAGE_SIZE, PAGE_SIZE); 102 if (!pmd_table) 103 panic("%s: Failed to allocate %lu bytes align=%lx\n", 104 __func__, PAGE_SIZE, PAGE_SIZE); 105 106 set_pud(pud, __pud(_KERNPG_TABLE + (unsigned long) __pa(pmd_table))); 107 BUG_ON(pmd_table != pmd_offset(pud, 0)); 108 #endif 109 } 110 111 static void __init fixrange_init(unsigned long start, unsigned long end, 112 pgd_t *pgd_base) 113 { 114 pgd_t *pgd; 115 p4d_t *p4d; 116 pud_t *pud; 117 pmd_t *pmd; 118 int i, j; 119 unsigned long vaddr; 120 121 vaddr = start; 122 i = pgd_index(vaddr); 123 j = pmd_index(vaddr); 124 pgd = pgd_base + i; 125 126 for ( ; (i < PTRS_PER_PGD) && (vaddr < end); pgd++, i++) { 127 p4d = p4d_offset(pgd, vaddr); 128 pud = pud_offset(p4d, vaddr); 129 if (pud_none(*pud)) 130 one_md_table_init(pud); 131 pmd = pmd_offset(pud, vaddr); 132 for (; (j < PTRS_PER_PMD) && (vaddr < end); pmd++, j++) { 133 one_page_table_init(pmd); 134 vaddr += PMD_SIZE; 135 } 136 j = 0; 137 } 138 } 139 140 static void __init fixaddr_user_init( void) 141 { 142 #ifdef CONFIG_ARCH_REUSE_HOST_VSYSCALL_AREA 143 long size = FIXADDR_USER_END - FIXADDR_USER_START; 144 pte_t *pte; 145 phys_t p; 146 unsigned long v, vaddr = FIXADDR_USER_START; 147 148 if (!size) 149 return; 150 151 fixrange_init( FIXADDR_USER_START, FIXADDR_USER_END, swapper_pg_dir); 152 v = (unsigned long) memblock_alloc_low(size, PAGE_SIZE); 153 if (!v) 154 panic("%s: Failed to allocate %lu bytes align=%lx\n", 155 __func__, size, PAGE_SIZE); 156 157 memcpy((void *) v , (void *) FIXADDR_USER_START, size); 158 p = __pa(v); 159 for ( ; size > 0; size -= PAGE_SIZE, vaddr += PAGE_SIZE, 160 p += PAGE_SIZE) { 161 pte = virt_to_kpte(vaddr); 162 pte_set_val(*pte, p, PAGE_READONLY); 163 } 164 #endif 165 } 166 167 void __init paging_init(void) 168 { 169 unsigned long max_zone_pfn[MAX_NR_ZONES] = { 0 }; 170 unsigned long vaddr; 171 172 empty_zero_page = (unsigned long *) memblock_alloc_low(PAGE_SIZE, 173 PAGE_SIZE); 174 if (!empty_zero_page) 175 panic("%s: Failed to allocate %lu bytes align=%lx\n", 176 __func__, PAGE_SIZE, PAGE_SIZE); 177 178 max_zone_pfn[ZONE_NORMAL] = end_iomem >> PAGE_SHIFT; 179 free_area_init(max_zone_pfn); 180 181 /* 182 * Fixed mappings, only the page table structure has to be 183 * created - mappings will be set by set_fixmap(): 184 */ 185 vaddr = __fix_to_virt(__end_of_fixed_addresses - 1) & PMD_MASK; 186 fixrange_init(vaddr, FIXADDR_TOP, swapper_pg_dir); 187 188 fixaddr_user_init(); 189 } 190 191 /* 192 * This can't do anything because nothing in the kernel image can be freed 193 * since it's not in kernel physical memory. 194 */ 195 196 void free_initmem(void) 197 { 198 } 199 200 /* Allocate and free page tables. */ 201 202 pgd_t *pgd_alloc(struct mm_struct *mm) 203 { 204 pgd_t *pgd = (pgd_t *)__get_free_page(GFP_KERNEL); 205 206 if (pgd) { 207 memset(pgd, 0, USER_PTRS_PER_PGD * sizeof(pgd_t)); 208 memcpy(pgd + USER_PTRS_PER_PGD, 209 swapper_pg_dir + USER_PTRS_PER_PGD, 210 (PTRS_PER_PGD - USER_PTRS_PER_PGD) * sizeof(pgd_t)); 211 } 212 return pgd; 213 } 214 215 void *uml_kmalloc(int size, int flags) 216 { 217 return kmalloc(size, flags); 218 } 219 220 static const pgprot_t protection_map[16] = { 221 [VM_NONE] = PAGE_NONE, 222 [VM_READ] = PAGE_READONLY, 223 [VM_WRITE] = PAGE_COPY, 224 [VM_WRITE | VM_READ] = PAGE_COPY, 225 [VM_EXEC] = PAGE_READONLY, 226 [VM_EXEC | VM_READ] = PAGE_READONLY, 227 [VM_EXEC | VM_WRITE] = PAGE_COPY, 228 [VM_EXEC | VM_WRITE | VM_READ] = PAGE_COPY, 229 [VM_SHARED] = PAGE_NONE, 230 [VM_SHARED | VM_READ] = PAGE_READONLY, 231 [VM_SHARED | VM_WRITE] = PAGE_SHARED, 232 [VM_SHARED | VM_WRITE | VM_READ] = PAGE_SHARED, 233 [VM_SHARED | VM_EXEC] = PAGE_READONLY, 234 [VM_SHARED | VM_EXEC | VM_READ] = PAGE_READONLY, 235 [VM_SHARED | VM_EXEC | VM_WRITE] = PAGE_SHARED, 236 [VM_SHARED | VM_EXEC | VM_WRITE | VM_READ] = PAGE_SHARED 237 }; 238 DECLARE_VM_GET_PAGE_PROT 239