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 mem_init(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 70 /* this will put all low memory onto the freelists */ 71 memblock_free_all(); 72 max_pfn = max_low_pfn; 73 kmalloc_ok = 1; 74 } 75 76 #if IS_ENABLED(CONFIG_ARCH_REUSE_HOST_VSYSCALL_AREA) 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 #if CONFIG_PGTABLE_LEVELS > 2 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 one_ud_table_init(p4d_t *p4d) 110 { 111 #if CONFIG_PGTABLE_LEVELS > 3 112 pud_t *pud_table = (pud_t *) memblock_alloc_low(PAGE_SIZE, PAGE_SIZE); 113 if (!pud_table) 114 panic("%s: Failed to allocate %lu bytes align=%lx\n", 115 __func__, PAGE_SIZE, PAGE_SIZE); 116 117 set_p4d(p4d, __p4d(_KERNPG_TABLE + (unsigned long) __pa(pud_table))); 118 BUG_ON(pud_table != pud_offset(p4d, 0)); 119 #endif 120 } 121 122 static void __init fixrange_init(unsigned long start, unsigned long end, 123 pgd_t *pgd_base) 124 { 125 pgd_t *pgd; 126 p4d_t *p4d; 127 pud_t *pud; 128 pmd_t *pmd; 129 int i, j; 130 unsigned long vaddr; 131 132 vaddr = start; 133 i = pgd_index(vaddr); 134 j = pmd_index(vaddr); 135 pgd = pgd_base + i; 136 137 for ( ; (i < PTRS_PER_PGD) && (vaddr < end); pgd++, i++) { 138 p4d = p4d_offset(pgd, vaddr); 139 if (p4d_none(*p4d)) 140 one_ud_table_init(p4d); 141 pud = pud_offset(p4d, vaddr); 142 if (pud_none(*pud)) 143 one_md_table_init(pud); 144 pmd = pmd_offset(pud, vaddr); 145 for (; (j < PTRS_PER_PMD) && (vaddr < end); pmd++, j++) { 146 one_page_table_init(pmd); 147 vaddr += PMD_SIZE; 148 } 149 j = 0; 150 } 151 } 152 153 static void __init fixaddr_user_init( void) 154 { 155 long size = FIXADDR_USER_END - FIXADDR_USER_START; 156 pte_t *pte; 157 phys_t p; 158 unsigned long v, vaddr = FIXADDR_USER_START; 159 160 if (!size) 161 return; 162 163 fixrange_init( FIXADDR_USER_START, FIXADDR_USER_END, swapper_pg_dir); 164 v = (unsigned long) memblock_alloc_low(size, PAGE_SIZE); 165 if (!v) 166 panic("%s: Failed to allocate %lu bytes align=%lx\n", 167 __func__, size, PAGE_SIZE); 168 169 memcpy((void *) v , (void *) FIXADDR_USER_START, size); 170 p = __pa(v); 171 for ( ; size > 0; size -= PAGE_SIZE, vaddr += PAGE_SIZE, 172 p += PAGE_SIZE) { 173 pte = virt_to_kpte(vaddr); 174 pte_set_val(*pte, p, PAGE_READONLY); 175 } 176 } 177 #endif 178 179 void __init paging_init(void) 180 { 181 unsigned long max_zone_pfn[MAX_NR_ZONES] = { 0 }; 182 183 empty_zero_page = (unsigned long *) memblock_alloc_low(PAGE_SIZE, 184 PAGE_SIZE); 185 if (!empty_zero_page) 186 panic("%s: Failed to allocate %lu bytes align=%lx\n", 187 __func__, PAGE_SIZE, PAGE_SIZE); 188 189 max_zone_pfn[ZONE_NORMAL] = end_iomem >> PAGE_SHIFT; 190 free_area_init(max_zone_pfn); 191 192 #if IS_ENABLED(CONFIG_ARCH_REUSE_HOST_VSYSCALL_AREA) 193 fixaddr_user_init(); 194 #endif 195 } 196 197 /* 198 * This can't do anything because nothing in the kernel image can be freed 199 * since it's not in kernel physical memory. 200 */ 201 202 void free_initmem(void) 203 { 204 } 205 206 /* Allocate and free page tables. */ 207 208 pgd_t *pgd_alloc(struct mm_struct *mm) 209 { 210 pgd_t *pgd = __pgd_alloc(mm, 0); 211 212 if (pgd) 213 memcpy(pgd + USER_PTRS_PER_PGD, 214 swapper_pg_dir + USER_PTRS_PER_PGD, 215 (PTRS_PER_PGD - USER_PTRS_PER_PGD) * sizeof(pgd_t)); 216 217 return pgd; 218 } 219 220 void *uml_kmalloc(int size, int flags) 221 { 222 return kmalloc(size, flags); 223 } 224 225 static const pgprot_t protection_map[16] = { 226 [VM_NONE] = PAGE_NONE, 227 [VM_READ] = PAGE_READONLY, 228 [VM_WRITE] = PAGE_COPY, 229 [VM_WRITE | VM_READ] = PAGE_COPY, 230 [VM_EXEC] = PAGE_READONLY, 231 [VM_EXEC | VM_READ] = PAGE_READONLY, 232 [VM_EXEC | VM_WRITE] = PAGE_COPY, 233 [VM_EXEC | VM_WRITE | VM_READ] = PAGE_COPY, 234 [VM_SHARED] = PAGE_NONE, 235 [VM_SHARED | VM_READ] = PAGE_READONLY, 236 [VM_SHARED | VM_WRITE] = PAGE_SHARED, 237 [VM_SHARED | VM_WRITE | VM_READ] = PAGE_SHARED, 238 [VM_SHARED | VM_EXEC] = PAGE_READONLY, 239 [VM_SHARED | VM_EXEC | VM_READ] = PAGE_READONLY, 240 [VM_SHARED | VM_EXEC | VM_WRITE] = PAGE_SHARED, 241 [VM_SHARED | VM_EXEC | VM_WRITE | VM_READ] = PAGE_SHARED 242 }; 243 DECLARE_VM_GET_PAGE_PROT 244