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/highmem.h> 10 #include <linux/mm.h> 11 #include <linux/swap.h> 12 #include <linux/slab.h> 13 #include <asm/fixmap.h> 14 #include <asm/page.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 22 /* allocated in paging_init, zeroed in mem_init, and unchanged thereafter */ 23 unsigned long *empty_zero_page = NULL; 24 EXPORT_SYMBOL(empty_zero_page); 25 26 /* 27 * Initialized during boot, and readonly for initializing page tables 28 * afterwards 29 */ 30 pgd_t swapper_pg_dir[PTRS_PER_PGD]; 31 32 /* Initialized at boot time, and readonly after that */ 33 unsigned long long highmem; 34 EXPORT_SYMBOL(highmem); 35 int kmalloc_ok = 0; 36 37 /* Used during early boot */ 38 static unsigned long brk_end; 39 40 void __init mem_init(void) 41 { 42 /* clear the zero-page */ 43 memset(empty_zero_page, 0, PAGE_SIZE); 44 45 /* Map in the area just after the brk now that kmalloc is about 46 * to be turned on. 47 */ 48 brk_end = (unsigned long) UML_ROUND_UP(sbrk(0)); 49 map_memory(brk_end, __pa(brk_end), uml_reserved - brk_end, 1, 1, 0); 50 memblock_free(__pa(brk_end), uml_reserved - brk_end); 51 uml_reserved = brk_end; 52 53 /* this will put all low memory onto the freelists */ 54 memblock_free_all(); 55 max_low_pfn = totalram_pages(); 56 max_pfn = max_low_pfn; 57 kmalloc_ok = 1; 58 } 59 60 /* 61 * Create a page table and place a pointer to it in a middle page 62 * directory entry. 63 */ 64 static void __init one_page_table_init(pmd_t *pmd) 65 { 66 if (pmd_none(*pmd)) { 67 pte_t *pte = (pte_t *) memblock_alloc_low(PAGE_SIZE, 68 PAGE_SIZE); 69 if (!pte) 70 panic("%s: Failed to allocate %lu bytes align=%lx\n", 71 __func__, PAGE_SIZE, PAGE_SIZE); 72 73 set_pmd(pmd, __pmd(_KERNPG_TABLE + 74 (unsigned long) __pa(pte))); 75 BUG_ON(pte != pte_offset_kernel(pmd, 0)); 76 } 77 } 78 79 static void __init one_md_table_init(pud_t *pud) 80 { 81 #ifdef CONFIG_3_LEVEL_PGTABLES 82 pmd_t *pmd_table = (pmd_t *) memblock_alloc_low(PAGE_SIZE, PAGE_SIZE); 83 if (!pmd_table) 84 panic("%s: Failed to allocate %lu bytes align=%lx\n", 85 __func__, PAGE_SIZE, PAGE_SIZE); 86 87 set_pud(pud, __pud(_KERNPG_TABLE + (unsigned long) __pa(pmd_table))); 88 if (pmd_table != pmd_offset(pud, 0)) 89 BUG(); 90 #endif 91 } 92 93 static void __init fixrange_init(unsigned long start, unsigned long end, 94 pgd_t *pgd_base) 95 { 96 pgd_t *pgd; 97 p4d_t *p4d; 98 pud_t *pud; 99 pmd_t *pmd; 100 int i, j; 101 unsigned long vaddr; 102 103 vaddr = start; 104 i = pgd_index(vaddr); 105 j = pmd_index(vaddr); 106 pgd = pgd_base + i; 107 108 for ( ; (i < PTRS_PER_PGD) && (vaddr < end); pgd++, i++) { 109 p4d = p4d_offset(pgd, vaddr); 110 pud = pud_offset(p4d, vaddr); 111 if (pud_none(*pud)) 112 one_md_table_init(pud); 113 pmd = pmd_offset(pud, vaddr); 114 for (; (j < PTRS_PER_PMD) && (vaddr < end); pmd++, j++) { 115 one_page_table_init(pmd); 116 vaddr += PMD_SIZE; 117 } 118 j = 0; 119 } 120 } 121 122 static void __init fixaddr_user_init( void) 123 { 124 #ifdef CONFIG_ARCH_REUSE_HOST_VSYSCALL_AREA 125 long size = FIXADDR_USER_END - FIXADDR_USER_START; 126 pte_t *pte; 127 phys_t p; 128 unsigned long v, vaddr = FIXADDR_USER_START; 129 130 if (!size) 131 return; 132 133 fixrange_init( FIXADDR_USER_START, FIXADDR_USER_END, swapper_pg_dir); 134 v = (unsigned long) memblock_alloc_low(size, PAGE_SIZE); 135 if (!v) 136 panic("%s: Failed to allocate %lu bytes align=%lx\n", 137 __func__, size, PAGE_SIZE); 138 139 memcpy((void *) v , (void *) FIXADDR_USER_START, size); 140 p = __pa(v); 141 for ( ; size > 0; size -= PAGE_SIZE, vaddr += PAGE_SIZE, 142 p += PAGE_SIZE) { 143 pte = virt_to_kpte(vaddr); 144 pte_set_val(*pte, p, PAGE_READONLY); 145 } 146 #endif 147 } 148 149 void __init paging_init(void) 150 { 151 unsigned long max_zone_pfn[MAX_NR_ZONES] = { 0 }; 152 unsigned long vaddr; 153 154 empty_zero_page = (unsigned long *) memblock_alloc_low(PAGE_SIZE, 155 PAGE_SIZE); 156 if (!empty_zero_page) 157 panic("%s: Failed to allocate %lu bytes align=%lx\n", 158 __func__, PAGE_SIZE, PAGE_SIZE); 159 160 max_zone_pfn[ZONE_NORMAL] = end_iomem >> PAGE_SHIFT; 161 free_area_init(max_zone_pfn); 162 163 /* 164 * Fixed mappings, only the page table structure has to be 165 * created - mappings will be set by set_fixmap(): 166 */ 167 vaddr = __fix_to_virt(__end_of_fixed_addresses - 1) & PMD_MASK; 168 fixrange_init(vaddr, FIXADDR_TOP, swapper_pg_dir); 169 170 fixaddr_user_init(); 171 } 172 173 /* 174 * This can't do anything because nothing in the kernel image can be freed 175 * since it's not in kernel physical memory. 176 */ 177 178 void free_initmem(void) 179 { 180 } 181 182 /* Allocate and free page tables. */ 183 184 pgd_t *pgd_alloc(struct mm_struct *mm) 185 { 186 pgd_t *pgd = (pgd_t *)__get_free_page(GFP_KERNEL); 187 188 if (pgd) { 189 memset(pgd, 0, USER_PTRS_PER_PGD * sizeof(pgd_t)); 190 memcpy(pgd + USER_PTRS_PER_PGD, 191 swapper_pg_dir + USER_PTRS_PER_PGD, 192 (PTRS_PER_PGD - USER_PTRS_PER_PGD) * sizeof(pgd_t)); 193 } 194 return pgd; 195 } 196 197 void *uml_kmalloc(int size, int flags) 198 { 199 return kmalloc(size, flags); 200 } 201