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/fixmap.h> 13 #include <asm/page.h> 14 #include <asm/pgalloc.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 <um_malloc.h> 22 #include <linux/sched/task.h> 23 24 #ifdef CONFIG_KASAN 25 int kasan_um_is_ready; 26 void kasan_init(void) 27 { 28 /* 29 * kasan_map_memory will map all of the required address space and 30 * the host machine will allocate physical memory as necessary. 31 */ 32 kasan_map_memory((void *)KASAN_SHADOW_START, KASAN_SHADOW_SIZE); 33 init_task.kasan_depth = 0; 34 kasan_um_is_ready = true; 35 } 36 37 static void (*kasan_init_ptr)(void) 38 __section(".kasan_init") __used 39 = kasan_init; 40 #endif 41 42 /* allocated in paging_init, zeroed in mem_init, and unchanged thereafter */ 43 unsigned long *empty_zero_page = NULL; 44 EXPORT_SYMBOL(empty_zero_page); 45 46 /* 47 * Initialized during boot, and readonly for initializing page tables 48 * afterwards 49 */ 50 pgd_t swapper_pg_dir[PTRS_PER_PGD]; 51 52 /* Initialized at boot time, and readonly after that */ 53 int kmalloc_ok = 0; 54 55 /* Used during early boot */ 56 static unsigned long brk_end; 57 58 void __init mem_init(void) 59 { 60 /* clear the zero-page */ 61 memset(empty_zero_page, 0, PAGE_SIZE); 62 63 /* Map in the area just after the brk now that kmalloc is about 64 * to be turned on. 65 */ 66 brk_end = (unsigned long) UML_ROUND_UP(sbrk(0)); 67 map_memory(brk_end, __pa(brk_end), uml_reserved - brk_end, 1, 1, 0); 68 memblock_free((void *)brk_end, uml_reserved - brk_end); 69 uml_reserved = brk_end; 70 71 /* this will put all low memory onto the freelists */ 72 memblock_free_all(); 73 max_pfn = max_low_pfn; 74 kmalloc_ok = 1; 75 } 76 77 /* 78 * Create a page table and place a pointer to it in a middle page 79 * directory entry. 80 */ 81 static void __init one_page_table_init(pmd_t *pmd) 82 { 83 if (pmd_none(*pmd)) { 84 pte_t *pte = (pte_t *) memblock_alloc_low(PAGE_SIZE, 85 PAGE_SIZE); 86 if (!pte) 87 panic("%s: Failed to allocate %lu bytes align=%lx\n", 88 __func__, PAGE_SIZE, PAGE_SIZE); 89 90 set_pmd(pmd, __pmd(_KERNPG_TABLE + 91 (unsigned long) __pa(pte))); 92 BUG_ON(pte != pte_offset_kernel(pmd, 0)); 93 } 94 } 95 96 static void __init one_md_table_init(pud_t *pud) 97 { 98 #ifdef CONFIG_3_LEVEL_PGTABLES 99 pmd_t *pmd_table = (pmd_t *) memblock_alloc_low(PAGE_SIZE, PAGE_SIZE); 100 if (!pmd_table) 101 panic("%s: Failed to allocate %lu bytes align=%lx\n", 102 __func__, PAGE_SIZE, PAGE_SIZE); 103 104 set_pud(pud, __pud(_KERNPG_TABLE + (unsigned long) __pa(pmd_table))); 105 BUG_ON(pmd_table != pmd_offset(pud, 0)); 106 #endif 107 } 108 109 static void __init fixrange_init(unsigned long start, unsigned long end, 110 pgd_t *pgd_base) 111 { 112 pgd_t *pgd; 113 p4d_t *p4d; 114 pud_t *pud; 115 pmd_t *pmd; 116 int i, j; 117 unsigned long vaddr; 118 119 vaddr = start; 120 i = pgd_index(vaddr); 121 j = pmd_index(vaddr); 122 pgd = pgd_base + i; 123 124 for ( ; (i < PTRS_PER_PGD) && (vaddr < end); pgd++, i++) { 125 p4d = p4d_offset(pgd, vaddr); 126 pud = pud_offset(p4d, vaddr); 127 if (pud_none(*pud)) 128 one_md_table_init(pud); 129 pmd = pmd_offset(pud, vaddr); 130 for (; (j < PTRS_PER_PMD) && (vaddr < end); pmd++, j++) { 131 one_page_table_init(pmd); 132 vaddr += PMD_SIZE; 133 } 134 j = 0; 135 } 136 } 137 138 static void __init fixaddr_user_init( void) 139 { 140 #ifdef CONFIG_ARCH_REUSE_HOST_VSYSCALL_AREA 141 long size = FIXADDR_USER_END - FIXADDR_USER_START; 142 pte_t *pte; 143 phys_t p; 144 unsigned long v, vaddr = FIXADDR_USER_START; 145 146 if (!size) 147 return; 148 149 fixrange_init( FIXADDR_USER_START, FIXADDR_USER_END, swapper_pg_dir); 150 v = (unsigned long) memblock_alloc_low(size, PAGE_SIZE); 151 if (!v) 152 panic("%s: Failed to allocate %lu bytes align=%lx\n", 153 __func__, size, PAGE_SIZE); 154 155 memcpy((void *) v , (void *) FIXADDR_USER_START, size); 156 p = __pa(v); 157 for ( ; size > 0; size -= PAGE_SIZE, vaddr += PAGE_SIZE, 158 p += PAGE_SIZE) { 159 pte = virt_to_kpte(vaddr); 160 pte_set_val(*pte, p, PAGE_READONLY); 161 } 162 #endif 163 } 164 165 void __init paging_init(void) 166 { 167 unsigned long max_zone_pfn[MAX_NR_ZONES] = { 0 }; 168 unsigned long vaddr; 169 170 empty_zero_page = (unsigned long *) memblock_alloc_low(PAGE_SIZE, 171 PAGE_SIZE); 172 if (!empty_zero_page) 173 panic("%s: Failed to allocate %lu bytes align=%lx\n", 174 __func__, PAGE_SIZE, PAGE_SIZE); 175 176 max_zone_pfn[ZONE_NORMAL] = end_iomem >> PAGE_SHIFT; 177 free_area_init(max_zone_pfn); 178 179 /* 180 * Fixed mappings, only the page table structure has to be 181 * created - mappings will be set by set_fixmap(): 182 */ 183 vaddr = __fix_to_virt(__end_of_fixed_addresses - 1) & PMD_MASK; 184 fixrange_init(vaddr, FIXADDR_TOP, swapper_pg_dir); 185 186 fixaddr_user_init(); 187 } 188 189 /* 190 * This can't do anything because nothing in the kernel image can be freed 191 * since it's not in kernel physical memory. 192 */ 193 194 void free_initmem(void) 195 { 196 } 197 198 /* Allocate and free page tables. */ 199 200 pgd_t *pgd_alloc(struct mm_struct *mm) 201 { 202 pgd_t *pgd = (pgd_t *)__get_free_page(GFP_KERNEL); 203 204 if (pgd) { 205 memset(pgd, 0, USER_PTRS_PER_PGD * sizeof(pgd_t)); 206 memcpy(pgd + USER_PTRS_PER_PGD, 207 swapper_pg_dir + USER_PTRS_PER_PGD, 208 (PTRS_PER_PGD - USER_PTRS_PER_PGD) * sizeof(pgd_t)); 209 } 210 return pgd; 211 } 212 213 void *uml_kmalloc(int size, int flags) 214 { 215 return kmalloc(size, flags); 216 } 217 218 static const pgprot_t protection_map[16] = { 219 [VM_NONE] = PAGE_NONE, 220 [VM_READ] = PAGE_READONLY, 221 [VM_WRITE] = PAGE_COPY, 222 [VM_WRITE | VM_READ] = PAGE_COPY, 223 [VM_EXEC] = PAGE_READONLY, 224 [VM_EXEC | VM_READ] = PAGE_READONLY, 225 [VM_EXEC | VM_WRITE] = PAGE_COPY, 226 [VM_EXEC | VM_WRITE | VM_READ] = PAGE_COPY, 227 [VM_SHARED] = PAGE_NONE, 228 [VM_SHARED | VM_READ] = PAGE_READONLY, 229 [VM_SHARED | VM_WRITE] = PAGE_SHARED, 230 [VM_SHARED | VM_WRITE | VM_READ] = PAGE_SHARED, 231 [VM_SHARED | VM_EXEC] = PAGE_READONLY, 232 [VM_SHARED | VM_EXEC | VM_READ] = PAGE_READONLY, 233 [VM_SHARED | VM_EXEC | VM_WRITE] = PAGE_SHARED, 234 [VM_SHARED | VM_EXEC | VM_WRITE | VM_READ] = PAGE_SHARED 235 }; 236 DECLARE_VM_GET_PAGE_PROT 237