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