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((void *)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 BUG_ON(pmd_table != pmd_offset(pud, 0)); 89 #endif 90 } 91 92 static void __init fixrange_init(unsigned long start, unsigned long end, 93 pgd_t *pgd_base) 94 { 95 pgd_t *pgd; 96 p4d_t *p4d; 97 pud_t *pud; 98 pmd_t *pmd; 99 int i, j; 100 unsigned long vaddr; 101 102 vaddr = start; 103 i = pgd_index(vaddr); 104 j = pmd_index(vaddr); 105 pgd = pgd_base + i; 106 107 for ( ; (i < PTRS_PER_PGD) && (vaddr < end); pgd++, i++) { 108 p4d = p4d_offset(pgd, vaddr); 109 pud = pud_offset(p4d, vaddr); 110 if (pud_none(*pud)) 111 one_md_table_init(pud); 112 pmd = pmd_offset(pud, vaddr); 113 for (; (j < PTRS_PER_PMD) && (vaddr < end); pmd++, j++) { 114 one_page_table_init(pmd); 115 vaddr += PMD_SIZE; 116 } 117 j = 0; 118 } 119 } 120 121 static void __init fixaddr_user_init( void) 122 { 123 #ifdef CONFIG_ARCH_REUSE_HOST_VSYSCALL_AREA 124 long size = FIXADDR_USER_END - FIXADDR_USER_START; 125 pte_t *pte; 126 phys_t p; 127 unsigned long v, vaddr = FIXADDR_USER_START; 128 129 if (!size) 130 return; 131 132 fixrange_init( FIXADDR_USER_START, FIXADDR_USER_END, swapper_pg_dir); 133 v = (unsigned long) memblock_alloc_low(size, PAGE_SIZE); 134 if (!v) 135 panic("%s: Failed to allocate %lu bytes align=%lx\n", 136 __func__, size, PAGE_SIZE); 137 138 memcpy((void *) v , (void *) FIXADDR_USER_START, size); 139 p = __pa(v); 140 for ( ; size > 0; size -= PAGE_SIZE, vaddr += PAGE_SIZE, 141 p += PAGE_SIZE) { 142 pte = virt_to_kpte(vaddr); 143 pte_set_val(*pte, p, PAGE_READONLY); 144 } 145 #endif 146 } 147 148 void __init paging_init(void) 149 { 150 unsigned long max_zone_pfn[MAX_NR_ZONES] = { 0 }; 151 unsigned long vaddr; 152 153 empty_zero_page = (unsigned long *) memblock_alloc_low(PAGE_SIZE, 154 PAGE_SIZE); 155 if (!empty_zero_page) 156 panic("%s: Failed to allocate %lu bytes align=%lx\n", 157 __func__, PAGE_SIZE, PAGE_SIZE); 158 159 max_zone_pfn[ZONE_NORMAL] = end_iomem >> PAGE_SHIFT; 160 free_area_init(max_zone_pfn); 161 162 /* 163 * Fixed mappings, only the page table structure has to be 164 * created - mappings will be set by set_fixmap(): 165 */ 166 vaddr = __fix_to_virt(__end_of_fixed_addresses - 1) & PMD_MASK; 167 fixrange_init(vaddr, FIXADDR_TOP, swapper_pg_dir); 168 169 fixaddr_user_init(); 170 } 171 172 /* 173 * This can't do anything because nothing in the kernel image can be freed 174 * since it's not in kernel physical memory. 175 */ 176 177 void free_initmem(void) 178 { 179 } 180 181 /* Allocate and free page tables. */ 182 183 pgd_t *pgd_alloc(struct mm_struct *mm) 184 { 185 pgd_t *pgd = (pgd_t *)__get_free_page(GFP_KERNEL); 186 187 if (pgd) { 188 memset(pgd, 0, USER_PTRS_PER_PGD * sizeof(pgd_t)); 189 memcpy(pgd + USER_PTRS_PER_PGD, 190 swapper_pg_dir + USER_PTRS_PER_PGD, 191 (PTRS_PER_PGD - USER_PTRS_PER_PGD) * sizeof(pgd_t)); 192 } 193 return pgd; 194 } 195 196 void *uml_kmalloc(int size, int flags) 197 { 198 return kmalloc(size, flags); 199 } 200