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/mm.h> 10 #include <linux/swap.h> 11 #include <linux/slab.h> 12 #include <linux/init.h> 13 #include <asm/sections.h> 14 #include <asm/page.h> 15 #include <asm/pgalloc.h> 16 #include <as-layout.h> 17 #include <init.h> 18 #include <kern.h> 19 #include <kern_util.h> 20 #include <mem_user.h> 21 #include <os.h> 22 #include <um_malloc.h> 23 #include <linux/sched/task.h> 24 #include <linux/kasan.h> 25 26 #ifdef CONFIG_KASAN 27 void __init kasan_init(void) 28 { 29 /* 30 * kasan_map_memory will map all of the required address space and 31 * the host machine will allocate physical memory as necessary. 32 */ 33 kasan_map_memory((void *)KASAN_SHADOW_START, KASAN_SHADOW_SIZE); 34 init_task.kasan_depth = 0; 35 /* 36 * Since kasan_init() is called before main(), 37 * KASAN is initialized but the enablement is deferred after 38 * jump_label_init(). See arch_mm_preinit(). 39 */ 40 } 41 42 static void (*kasan_init_ptr)(void) 43 __section(".kasan_init") __used 44 = kasan_init; 45 #endif 46 47 /* allocated in paging_init, zeroed in mem_init, and unchanged thereafter */ 48 unsigned long *empty_zero_page = NULL; 49 EXPORT_SYMBOL(empty_zero_page); 50 51 /* 52 * Initialized during boot, and readonly for initializing page tables 53 * afterwards 54 */ 55 pgd_t swapper_pg_dir[PTRS_PER_PGD]; 56 57 /* Initialized at boot time, and readonly after that */ 58 int kmalloc_ok = 0; 59 60 /* Used during early boot */ 61 static unsigned long brk_end; 62 63 void __init arch_mm_preinit(void) 64 { 65 /* Safe to call after jump_label_init(). Enables KASAN. */ 66 kasan_init_generic(); 67 68 /* clear the zero-page */ 69 memset(empty_zero_page, 0, PAGE_SIZE); 70 71 /* Map in the area just after the brk now that kmalloc is about 72 * to be turned on. 73 */ 74 brk_end = (unsigned long) UML_ROUND_UP(sbrk(0)); 75 map_memory(brk_end, __pa(brk_end), uml_reserved - brk_end, 1, 1, 0); 76 memblock_free((void *)brk_end, uml_reserved - brk_end); 77 uml_reserved = brk_end; 78 min_low_pfn = PFN_UP(__pa(uml_reserved)); 79 max_pfn = max_low_pfn; 80 } 81 82 void __init mem_init(void) 83 { 84 kmalloc_ok = 1; 85 } 86 87 #if IS_ENABLED(CONFIG_ARCH_REUSE_HOST_VSYSCALL_AREA) 88 /* 89 * Create a page table and place a pointer to it in a middle page 90 * directory entry. 91 */ 92 static void __init one_page_table_init(pmd_t *pmd) 93 { 94 if (pmd_none(*pmd)) { 95 pte_t *pte = (pte_t *) memblock_alloc_low(PAGE_SIZE, 96 PAGE_SIZE); 97 if (!pte) 98 panic("%s: Failed to allocate %lu bytes align=%lx\n", 99 __func__, PAGE_SIZE, PAGE_SIZE); 100 101 set_pmd(pmd, __pmd(_KERNPG_TABLE + 102 (unsigned long) __pa(pte))); 103 BUG_ON(pte != pte_offset_kernel(pmd, 0)); 104 } 105 } 106 107 static void __init one_md_table_init(pud_t *pud) 108 { 109 #if CONFIG_PGTABLE_LEVELS > 2 110 pmd_t *pmd_table = (pmd_t *) memblock_alloc_low(PAGE_SIZE, PAGE_SIZE); 111 if (!pmd_table) 112 panic("%s: Failed to allocate %lu bytes align=%lx\n", 113 __func__, PAGE_SIZE, PAGE_SIZE); 114 115 set_pud(pud, __pud(_KERNPG_TABLE + (unsigned long) __pa(pmd_table))); 116 BUG_ON(pmd_table != pmd_offset(pud, 0)); 117 #endif 118 } 119 120 static void __init one_ud_table_init(p4d_t *p4d) 121 { 122 #if CONFIG_PGTABLE_LEVELS > 3 123 pud_t *pud_table = (pud_t *) memblock_alloc_low(PAGE_SIZE, PAGE_SIZE); 124 if (!pud_table) 125 panic("%s: Failed to allocate %lu bytes align=%lx\n", 126 __func__, PAGE_SIZE, PAGE_SIZE); 127 128 set_p4d(p4d, __p4d(_KERNPG_TABLE + (unsigned long) __pa(pud_table))); 129 BUG_ON(pud_table != pud_offset(p4d, 0)); 130 #endif 131 } 132 133 static void __init fixrange_init(unsigned long start, unsigned long end, 134 pgd_t *pgd_base) 135 { 136 pgd_t *pgd; 137 p4d_t *p4d; 138 pud_t *pud; 139 pmd_t *pmd; 140 int i, j; 141 unsigned long vaddr; 142 143 vaddr = start; 144 i = pgd_index(vaddr); 145 j = pmd_index(vaddr); 146 pgd = pgd_base + i; 147 148 for ( ; (i < PTRS_PER_PGD) && (vaddr < end); pgd++, i++) { 149 p4d = p4d_offset(pgd, vaddr); 150 if (p4d_none(*p4d)) 151 one_ud_table_init(p4d); 152 pud = pud_offset(p4d, vaddr); 153 if (pud_none(*pud)) 154 one_md_table_init(pud); 155 pmd = pmd_offset(pud, vaddr); 156 for (; (j < PTRS_PER_PMD) && (vaddr < end); pmd++, j++) { 157 one_page_table_init(pmd); 158 vaddr += PMD_SIZE; 159 } 160 j = 0; 161 } 162 } 163 164 static void __init fixaddr_user_init( void) 165 { 166 long size = FIXADDR_USER_END - FIXADDR_USER_START; 167 pte_t *pte; 168 phys_t p; 169 unsigned long v, vaddr = FIXADDR_USER_START; 170 171 if (!size) 172 return; 173 174 fixrange_init( FIXADDR_USER_START, FIXADDR_USER_END, swapper_pg_dir); 175 v = (unsigned long) memblock_alloc_low(size, PAGE_SIZE); 176 if (!v) 177 panic("%s: Failed to allocate %lu bytes align=%lx\n", 178 __func__, size, PAGE_SIZE); 179 180 memcpy((void *) v , (void *) FIXADDR_USER_START, size); 181 p = __pa(v); 182 for ( ; size > 0; size -= PAGE_SIZE, vaddr += PAGE_SIZE, 183 p += PAGE_SIZE) { 184 pte = virt_to_kpte(vaddr); 185 pte_set_val(*pte, p, PAGE_READONLY); 186 } 187 } 188 #endif 189 190 void __init paging_init(void) 191 { 192 unsigned long max_zone_pfn[MAX_NR_ZONES] = { 0 }; 193 194 empty_zero_page = (unsigned long *) memblock_alloc_low(PAGE_SIZE, 195 PAGE_SIZE); 196 if (!empty_zero_page) 197 panic("%s: Failed to allocate %lu bytes align=%lx\n", 198 __func__, PAGE_SIZE, PAGE_SIZE); 199 200 max_zone_pfn[ZONE_NORMAL] = end_iomem >> PAGE_SHIFT; 201 free_area_init(max_zone_pfn); 202 203 #if IS_ENABLED(CONFIG_ARCH_REUSE_HOST_VSYSCALL_AREA) 204 fixaddr_user_init(); 205 #endif 206 } 207 208 /* 209 * This can't do anything because nothing in the kernel image can be freed 210 * since it's not in kernel physical memory. 211 */ 212 213 void free_initmem(void) 214 { 215 } 216 217 /* Allocate and free page tables. */ 218 219 pgd_t *pgd_alloc(struct mm_struct *mm) 220 { 221 pgd_t *pgd = __pgd_alloc(mm, 0); 222 223 if (pgd) 224 memcpy(pgd + USER_PTRS_PER_PGD, 225 swapper_pg_dir + USER_PTRS_PER_PGD, 226 (PTRS_PER_PGD - USER_PTRS_PER_PGD) * sizeof(pgd_t)); 227 228 return pgd; 229 } 230 231 void *uml_kmalloc(int size, int flags) 232 { 233 return kmalloc(size, flags); 234 } 235 236 static const pgprot_t protection_map[16] = { 237 [VM_NONE] = PAGE_NONE, 238 [VM_READ] = PAGE_READONLY, 239 [VM_WRITE] = PAGE_COPY, 240 [VM_WRITE | VM_READ] = PAGE_COPY, 241 [VM_EXEC] = PAGE_READONLY, 242 [VM_EXEC | VM_READ] = PAGE_READONLY, 243 [VM_EXEC | VM_WRITE] = PAGE_COPY, 244 [VM_EXEC | VM_WRITE | VM_READ] = PAGE_COPY, 245 [VM_SHARED] = PAGE_NONE, 246 [VM_SHARED | VM_READ] = PAGE_READONLY, 247 [VM_SHARED | VM_WRITE] = PAGE_SHARED, 248 [VM_SHARED | VM_WRITE | VM_READ] = PAGE_SHARED, 249 [VM_SHARED | VM_EXEC] = PAGE_READONLY, 250 [VM_SHARED | VM_EXEC | VM_READ] = PAGE_READONLY, 251 [VM_SHARED | VM_EXEC | VM_WRITE] = PAGE_SHARED, 252 [VM_SHARED | VM_EXEC | VM_WRITE | VM_READ] = PAGE_SHARED 253 }; 254 DECLARE_VM_GET_PAGE_PROT 255 256 void mark_rodata_ro(void) 257 { 258 unsigned long rodata_start = PFN_ALIGN(__start_rodata); 259 unsigned long rodata_end = PFN_ALIGN(__end_rodata); 260 261 os_protect_memory((void *)rodata_start, rodata_end - rodata_start, 1, 0, 0); 262 } 263