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 25 #ifdef CONFIG_KASAN 26 int kasan_um_is_ready; 27 void 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 kasan_um_is_ready = true; 36 } 37 38 static void (*kasan_init_ptr)(void) 39 __section(".kasan_init") __used 40 = kasan_init; 41 #endif 42 43 /* allocated in paging_init, zeroed in mem_init, and unchanged thereafter */ 44 unsigned long *empty_zero_page = NULL; 45 EXPORT_SYMBOL(empty_zero_page); 46 47 /* 48 * Initialized during boot, and readonly for initializing page tables 49 * afterwards 50 */ 51 pgd_t swapper_pg_dir[PTRS_PER_PGD]; 52 53 /* Initialized at boot time, and readonly after that */ 54 int kmalloc_ok = 0; 55 56 /* Used during early boot */ 57 static unsigned long brk_end; 58 59 void __init arch_mm_preinit(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 min_low_pfn = PFN_UP(__pa(uml_reserved)); 72 max_pfn = max_low_pfn; 73 } 74 75 void __init mem_init(void) 76 { 77 kmalloc_ok = 1; 78 } 79 80 #if IS_ENABLED(CONFIG_ARCH_REUSE_HOST_VSYSCALL_AREA) 81 /* 82 * Create a page table and place a pointer to it in a middle page 83 * directory entry. 84 */ 85 static void __init one_page_table_init(pmd_t *pmd) 86 { 87 if (pmd_none(*pmd)) { 88 pte_t *pte = (pte_t *) memblock_alloc_low(PAGE_SIZE, 89 PAGE_SIZE); 90 if (!pte) 91 panic("%s: Failed to allocate %lu bytes align=%lx\n", 92 __func__, PAGE_SIZE, PAGE_SIZE); 93 94 set_pmd(pmd, __pmd(_KERNPG_TABLE + 95 (unsigned long) __pa(pte))); 96 BUG_ON(pte != pte_offset_kernel(pmd, 0)); 97 } 98 } 99 100 static void __init one_md_table_init(pud_t *pud) 101 { 102 #if CONFIG_PGTABLE_LEVELS > 2 103 pmd_t *pmd_table = (pmd_t *) memblock_alloc_low(PAGE_SIZE, PAGE_SIZE); 104 if (!pmd_table) 105 panic("%s: Failed to allocate %lu bytes align=%lx\n", 106 __func__, PAGE_SIZE, PAGE_SIZE); 107 108 set_pud(pud, __pud(_KERNPG_TABLE + (unsigned long) __pa(pmd_table))); 109 BUG_ON(pmd_table != pmd_offset(pud, 0)); 110 #endif 111 } 112 113 static void __init one_ud_table_init(p4d_t *p4d) 114 { 115 #if CONFIG_PGTABLE_LEVELS > 3 116 pud_t *pud_table = (pud_t *) memblock_alloc_low(PAGE_SIZE, PAGE_SIZE); 117 if (!pud_table) 118 panic("%s: Failed to allocate %lu bytes align=%lx\n", 119 __func__, PAGE_SIZE, PAGE_SIZE); 120 121 set_p4d(p4d, __p4d(_KERNPG_TABLE + (unsigned long) __pa(pud_table))); 122 BUG_ON(pud_table != pud_offset(p4d, 0)); 123 #endif 124 } 125 126 static void __init fixrange_init(unsigned long start, unsigned long end, 127 pgd_t *pgd_base) 128 { 129 pgd_t *pgd; 130 p4d_t *p4d; 131 pud_t *pud; 132 pmd_t *pmd; 133 int i, j; 134 unsigned long vaddr; 135 136 vaddr = start; 137 i = pgd_index(vaddr); 138 j = pmd_index(vaddr); 139 pgd = pgd_base + i; 140 141 for ( ; (i < PTRS_PER_PGD) && (vaddr < end); pgd++, i++) { 142 p4d = p4d_offset(pgd, vaddr); 143 if (p4d_none(*p4d)) 144 one_ud_table_init(p4d); 145 pud = pud_offset(p4d, vaddr); 146 if (pud_none(*pud)) 147 one_md_table_init(pud); 148 pmd = pmd_offset(pud, vaddr); 149 for (; (j < PTRS_PER_PMD) && (vaddr < end); pmd++, j++) { 150 one_page_table_init(pmd); 151 vaddr += PMD_SIZE; 152 } 153 j = 0; 154 } 155 } 156 157 static void __init fixaddr_user_init( void) 158 { 159 long size = FIXADDR_USER_END - FIXADDR_USER_START; 160 pte_t *pte; 161 phys_t p; 162 unsigned long v, vaddr = FIXADDR_USER_START; 163 164 if (!size) 165 return; 166 167 fixrange_init( FIXADDR_USER_START, FIXADDR_USER_END, swapper_pg_dir); 168 v = (unsigned long) memblock_alloc_low(size, PAGE_SIZE); 169 if (!v) 170 panic("%s: Failed to allocate %lu bytes align=%lx\n", 171 __func__, size, PAGE_SIZE); 172 173 memcpy((void *) v , (void *) FIXADDR_USER_START, size); 174 p = __pa(v); 175 for ( ; size > 0; size -= PAGE_SIZE, vaddr += PAGE_SIZE, 176 p += PAGE_SIZE) { 177 pte = virt_to_kpte(vaddr); 178 pte_set_val(*pte, p, PAGE_READONLY); 179 } 180 } 181 #endif 182 183 void __init paging_init(void) 184 { 185 unsigned long max_zone_pfn[MAX_NR_ZONES] = { 0 }; 186 187 empty_zero_page = (unsigned long *) memblock_alloc_low(PAGE_SIZE, 188 PAGE_SIZE); 189 if (!empty_zero_page) 190 panic("%s: Failed to allocate %lu bytes align=%lx\n", 191 __func__, PAGE_SIZE, PAGE_SIZE); 192 193 max_zone_pfn[ZONE_NORMAL] = end_iomem >> PAGE_SHIFT; 194 free_area_init(max_zone_pfn); 195 196 #if IS_ENABLED(CONFIG_ARCH_REUSE_HOST_VSYSCALL_AREA) 197 fixaddr_user_init(); 198 #endif 199 } 200 201 /* 202 * This can't do anything because nothing in the kernel image can be freed 203 * since it's not in kernel physical memory. 204 */ 205 206 void free_initmem(void) 207 { 208 } 209 210 /* Allocate and free page tables. */ 211 212 pgd_t *pgd_alloc(struct mm_struct *mm) 213 { 214 pgd_t *pgd = __pgd_alloc(mm, 0); 215 216 if (pgd) 217 memcpy(pgd + USER_PTRS_PER_PGD, 218 swapper_pg_dir + USER_PTRS_PER_PGD, 219 (PTRS_PER_PGD - USER_PTRS_PER_PGD) * sizeof(pgd_t)); 220 221 return pgd; 222 } 223 224 void *uml_kmalloc(int size, int flags) 225 { 226 return kmalloc(size, flags); 227 } 228 229 static const pgprot_t protection_map[16] = { 230 [VM_NONE] = PAGE_NONE, 231 [VM_READ] = PAGE_READONLY, 232 [VM_WRITE] = PAGE_COPY, 233 [VM_WRITE | VM_READ] = PAGE_COPY, 234 [VM_EXEC] = PAGE_READONLY, 235 [VM_EXEC | VM_READ] = PAGE_READONLY, 236 [VM_EXEC | VM_WRITE] = PAGE_COPY, 237 [VM_EXEC | VM_WRITE | VM_READ] = PAGE_COPY, 238 [VM_SHARED] = PAGE_NONE, 239 [VM_SHARED | VM_READ] = PAGE_READONLY, 240 [VM_SHARED | VM_WRITE] = PAGE_SHARED, 241 [VM_SHARED | VM_WRITE | VM_READ] = PAGE_SHARED, 242 [VM_SHARED | VM_EXEC] = PAGE_READONLY, 243 [VM_SHARED | VM_EXEC | VM_READ] = PAGE_READONLY, 244 [VM_SHARED | VM_EXEC | VM_WRITE] = PAGE_SHARED, 245 [VM_SHARED | VM_EXEC | VM_WRITE | VM_READ] = PAGE_SHARED 246 }; 247 DECLARE_VM_GET_PAGE_PROT 248 249 void mark_rodata_ro(void) 250 { 251 unsigned long rodata_start = PFN_ALIGN(__start_rodata); 252 unsigned long rodata_end = PFN_ALIGN(__end_rodata); 253 254 os_protect_memory((void *)rodata_start, rodata_end - rodata_start, 1, 0, 0); 255 } 256