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 <asm/page.h> 13 #include <asm/pgalloc.h> 14 #include <as-layout.h> 15 #include <init.h> 16 #include <kern.h> 17 #include <kern_util.h> 18 #include <mem_user.h> 19 #include <os.h> 20 #include <um_malloc.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 int kmalloc_ok = 0; 53 54 /* Used during early boot */ 55 static unsigned long brk_end; 56 57 void __init arch_mm_preinit(void) 58 { 59 /* clear the zero-page */ 60 memset(empty_zero_page, 0, PAGE_SIZE); 61 62 /* Map in the area just after the brk now that kmalloc is about 63 * to be turned on. 64 */ 65 brk_end = (unsigned long) UML_ROUND_UP(sbrk(0)); 66 map_memory(brk_end, __pa(brk_end), uml_reserved - brk_end, 1, 1, 0); 67 memblock_free((void *)brk_end, uml_reserved - brk_end); 68 uml_reserved = brk_end; 69 max_pfn = max_low_pfn; 70 } 71 72 void __init mem_init(void) 73 { 74 kmalloc_ok = 1; 75 } 76 77 #if IS_ENABLED(CONFIG_ARCH_REUSE_HOST_VSYSCALL_AREA) 78 /* 79 * Create a page table and place a pointer to it in a middle page 80 * directory entry. 81 */ 82 static void __init one_page_table_init(pmd_t *pmd) 83 { 84 if (pmd_none(*pmd)) { 85 pte_t *pte = (pte_t *) memblock_alloc_low(PAGE_SIZE, 86 PAGE_SIZE); 87 if (!pte) 88 panic("%s: Failed to allocate %lu bytes align=%lx\n", 89 __func__, PAGE_SIZE, PAGE_SIZE); 90 91 set_pmd(pmd, __pmd(_KERNPG_TABLE + 92 (unsigned long) __pa(pte))); 93 BUG_ON(pte != pte_offset_kernel(pmd, 0)); 94 } 95 } 96 97 static void __init one_md_table_init(pud_t *pud) 98 { 99 #if CONFIG_PGTABLE_LEVELS > 2 100 pmd_t *pmd_table = (pmd_t *) memblock_alloc_low(PAGE_SIZE, PAGE_SIZE); 101 if (!pmd_table) 102 panic("%s: Failed to allocate %lu bytes align=%lx\n", 103 __func__, PAGE_SIZE, PAGE_SIZE); 104 105 set_pud(pud, __pud(_KERNPG_TABLE + (unsigned long) __pa(pmd_table))); 106 BUG_ON(pmd_table != pmd_offset(pud, 0)); 107 #endif 108 } 109 110 static void __init one_ud_table_init(p4d_t *p4d) 111 { 112 #if CONFIG_PGTABLE_LEVELS > 3 113 pud_t *pud_table = (pud_t *) memblock_alloc_low(PAGE_SIZE, PAGE_SIZE); 114 if (!pud_table) 115 panic("%s: Failed to allocate %lu bytes align=%lx\n", 116 __func__, PAGE_SIZE, PAGE_SIZE); 117 118 set_p4d(p4d, __p4d(_KERNPG_TABLE + (unsigned long) __pa(pud_table))); 119 BUG_ON(pud_table != pud_offset(p4d, 0)); 120 #endif 121 } 122 123 static void __init fixrange_init(unsigned long start, unsigned long end, 124 pgd_t *pgd_base) 125 { 126 pgd_t *pgd; 127 p4d_t *p4d; 128 pud_t *pud; 129 pmd_t *pmd; 130 int i, j; 131 unsigned long vaddr; 132 133 vaddr = start; 134 i = pgd_index(vaddr); 135 j = pmd_index(vaddr); 136 pgd = pgd_base + i; 137 138 for ( ; (i < PTRS_PER_PGD) && (vaddr < end); pgd++, i++) { 139 p4d = p4d_offset(pgd, vaddr); 140 if (p4d_none(*p4d)) 141 one_ud_table_init(p4d); 142 pud = pud_offset(p4d, vaddr); 143 if (pud_none(*pud)) 144 one_md_table_init(pud); 145 pmd = pmd_offset(pud, vaddr); 146 for (; (j < PTRS_PER_PMD) && (vaddr < end); pmd++, j++) { 147 one_page_table_init(pmd); 148 vaddr += PMD_SIZE; 149 } 150 j = 0; 151 } 152 } 153 154 static void __init fixaddr_user_init( void) 155 { 156 long size = FIXADDR_USER_END - FIXADDR_USER_START; 157 pte_t *pte; 158 phys_t p; 159 unsigned long v, vaddr = FIXADDR_USER_START; 160 161 if (!size) 162 return; 163 164 fixrange_init( FIXADDR_USER_START, FIXADDR_USER_END, swapper_pg_dir); 165 v = (unsigned long) memblock_alloc_low(size, PAGE_SIZE); 166 if (!v) 167 panic("%s: Failed to allocate %lu bytes align=%lx\n", 168 __func__, size, PAGE_SIZE); 169 170 memcpy((void *) v , (void *) FIXADDR_USER_START, size); 171 p = __pa(v); 172 for ( ; size > 0; size -= PAGE_SIZE, vaddr += PAGE_SIZE, 173 p += PAGE_SIZE) { 174 pte = virt_to_kpte(vaddr); 175 pte_set_val(*pte, p, PAGE_READONLY); 176 } 177 } 178 #endif 179 180 void __init paging_init(void) 181 { 182 unsigned long max_zone_pfn[MAX_NR_ZONES] = { 0 }; 183 184 empty_zero_page = (unsigned long *) memblock_alloc_low(PAGE_SIZE, 185 PAGE_SIZE); 186 if (!empty_zero_page) 187 panic("%s: Failed to allocate %lu bytes align=%lx\n", 188 __func__, PAGE_SIZE, PAGE_SIZE); 189 190 max_zone_pfn[ZONE_NORMAL] = end_iomem >> PAGE_SHIFT; 191 free_area_init(max_zone_pfn); 192 193 #if IS_ENABLED(CONFIG_ARCH_REUSE_HOST_VSYSCALL_AREA) 194 fixaddr_user_init(); 195 #endif 196 } 197 198 /* 199 * This can't do anything because nothing in the kernel image can be freed 200 * since it's not in kernel physical memory. 201 */ 202 203 void free_initmem(void) 204 { 205 } 206 207 /* Allocate and free page tables. */ 208 209 pgd_t *pgd_alloc(struct mm_struct *mm) 210 { 211 pgd_t *pgd = __pgd_alloc(mm, 0); 212 213 if (pgd) 214 memcpy(pgd + USER_PTRS_PER_PGD, 215 swapper_pg_dir + USER_PTRS_PER_PGD, 216 (PTRS_PER_PGD - USER_PTRS_PER_PGD) * sizeof(pgd_t)); 217 218 return pgd; 219 } 220 221 void *uml_kmalloc(int size, int flags) 222 { 223 return kmalloc(size, flags); 224 } 225 226 static const pgprot_t protection_map[16] = { 227 [VM_NONE] = PAGE_NONE, 228 [VM_READ] = PAGE_READONLY, 229 [VM_WRITE] = PAGE_COPY, 230 [VM_WRITE | VM_READ] = PAGE_COPY, 231 [VM_EXEC] = PAGE_READONLY, 232 [VM_EXEC | VM_READ] = PAGE_READONLY, 233 [VM_EXEC | VM_WRITE] = PAGE_COPY, 234 [VM_EXEC | VM_WRITE | VM_READ] = PAGE_COPY, 235 [VM_SHARED] = PAGE_NONE, 236 [VM_SHARED | VM_READ] = PAGE_READONLY, 237 [VM_SHARED | VM_WRITE] = PAGE_SHARED, 238 [VM_SHARED | VM_WRITE | VM_READ] = PAGE_SHARED, 239 [VM_SHARED | VM_EXEC] = PAGE_READONLY, 240 [VM_SHARED | VM_EXEC | VM_READ] = PAGE_READONLY, 241 [VM_SHARED | VM_EXEC | VM_WRITE] = PAGE_SHARED, 242 [VM_SHARED | VM_EXEC | VM_WRITE | VM_READ] = PAGE_SHARED 243 }; 244 DECLARE_VM_GET_PAGE_PROT 245