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