1 // SPDX-License-Identifier: GPL-2.0
3 * Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
6 #include <linux/stddef.h>
7 #include <linux/module.h>
8 #include <linux/memblock.h>
9 #include <linux/highmem.h>
11 #include <linux/swap.h>
12 #include <linux/slab.h>
13 #include <asm/fixmap.h>
15 #include <as-layout.h>
18 #include <kern_util.h>
21 #include <linux/sched/task.h>
24 int kasan_um_is_ready;
28 * kasan_map_memory will map all of the required address space and
29 * the host machine will allocate physical memory as necessary.
31 kasan_map_memory((void *)KASAN_SHADOW_START, KASAN_SHADOW_SIZE);
32 init_task.kasan_depth = 0;
33 kasan_um_is_ready = true;
36 static void (*kasan_init_ptr)(void)
37 __section(".kasan_init") __used
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);
46 * Initialized during boot, and readonly for initializing page tables
49 pgd_t swapper_pg_dir[PTRS_PER_PGD];
51 /* Initialized at boot time, and readonly after that */
52 unsigned long long highmem;
53 EXPORT_SYMBOL(highmem);
56 /* Used during early boot */
57 static unsigned long brk_end;
59 void __init mem_init(void)
61 /* clear the zero-page */
62 memset(empty_zero_page, 0, PAGE_SIZE);
64 /* Map in the area just after the brk now that kmalloc is about
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;
72 /* this will put all low memory onto the freelists */
74 max_low_pfn = totalram_pages();
75 max_pfn = max_low_pfn;
80 * Create a page table and place a pointer to it in a middle page
83 static void __init one_page_table_init(pmd_t *pmd)
86 pte_t *pte = (pte_t *) memblock_alloc_low(PAGE_SIZE,
89 panic("%s: Failed to allocate %lu bytes align=%lx\n",
90 __func__, PAGE_SIZE, PAGE_SIZE);
92 set_pmd(pmd, __pmd(_KERNPG_TABLE +
93 (unsigned long) __pa(pte)));
94 BUG_ON(pte != pte_offset_kernel(pmd, 0));
98 static void __init one_md_table_init(pud_t *pud)
100 #ifdef CONFIG_3_LEVEL_PGTABLES
101 pmd_t *pmd_table = (pmd_t *) memblock_alloc_low(PAGE_SIZE, PAGE_SIZE);
103 panic("%s: Failed to allocate %lu bytes align=%lx\n",
104 __func__, PAGE_SIZE, PAGE_SIZE);
106 set_pud(pud, __pud(_KERNPG_TABLE + (unsigned long) __pa(pmd_table)));
107 BUG_ON(pmd_table != pmd_offset(pud, 0));
111 static void __init fixrange_init(unsigned long start, unsigned long end,
122 i = pgd_index(vaddr);
123 j = pmd_index(vaddr);
126 for ( ; (i < PTRS_PER_PGD) && (vaddr < end); pgd++, i++) {
127 p4d = p4d_offset(pgd, vaddr);
128 pud = pud_offset(p4d, vaddr);
130 one_md_table_init(pud);
131 pmd = pmd_offset(pud, vaddr);
132 for (; (j < PTRS_PER_PMD) && (vaddr < end); pmd++, j++) {
133 one_page_table_init(pmd);
140 static void __init fixaddr_user_init( void)
142 #ifdef CONFIG_ARCH_REUSE_HOST_VSYSCALL_AREA
143 long size = FIXADDR_USER_END - FIXADDR_USER_START;
146 unsigned long v, vaddr = FIXADDR_USER_START;
151 fixrange_init( FIXADDR_USER_START, FIXADDR_USER_END, swapper_pg_dir);
152 v = (unsigned long) memblock_alloc_low(size, PAGE_SIZE);
154 panic("%s: Failed to allocate %lu bytes align=%lx\n",
155 __func__, size, PAGE_SIZE);
157 memcpy((void *) v , (void *) FIXADDR_USER_START, size);
159 for ( ; size > 0; size -= PAGE_SIZE, vaddr += PAGE_SIZE,
161 pte = virt_to_kpte(vaddr);
162 pte_set_val(*pte, p, PAGE_READONLY);
167 void __init paging_init(void)
169 unsigned long max_zone_pfn[MAX_NR_ZONES] = { 0 };
172 empty_zero_page = (unsigned long *) memblock_alloc_low(PAGE_SIZE,
174 if (!empty_zero_page)
175 panic("%s: Failed to allocate %lu bytes align=%lx\n",
176 __func__, PAGE_SIZE, PAGE_SIZE);
178 max_zone_pfn[ZONE_NORMAL] = end_iomem >> PAGE_SHIFT;
179 free_area_init(max_zone_pfn);
182 * Fixed mappings, only the page table structure has to be
183 * created - mappings will be set by set_fixmap():
185 vaddr = __fix_to_virt(__end_of_fixed_addresses - 1) & PMD_MASK;
186 fixrange_init(vaddr, FIXADDR_TOP, swapper_pg_dir);
192 * This can't do anything because nothing in the kernel image can be freed
193 * since it's not in kernel physical memory.
196 void free_initmem(void)
200 /* Allocate and free page tables. */
202 pgd_t *pgd_alloc(struct mm_struct *mm)
204 pgd_t *pgd = (pgd_t *)__get_free_page(GFP_KERNEL);
207 memset(pgd, 0, USER_PTRS_PER_PGD * sizeof(pgd_t));
208 memcpy(pgd + USER_PTRS_PER_PGD,
209 swapper_pg_dir + USER_PTRS_PER_PGD,
210 (PTRS_PER_PGD - USER_PTRS_PER_PGD) * sizeof(pgd_t));
215 void *uml_kmalloc(int size, int flags)
217 return kmalloc(size, flags);
220 static const pgprot_t protection_map[16] = {
221 [VM_NONE] = PAGE_NONE,
222 [VM_READ] = PAGE_READONLY,
223 [VM_WRITE] = PAGE_COPY,
224 [VM_WRITE | VM_READ] = PAGE_COPY,
225 [VM_EXEC] = PAGE_READONLY,
226 [VM_EXEC | VM_READ] = PAGE_READONLY,
227 [VM_EXEC | VM_WRITE] = PAGE_COPY,
228 [VM_EXEC | VM_WRITE | VM_READ] = PAGE_COPY,
229 [VM_SHARED] = PAGE_NONE,
230 [VM_SHARED | VM_READ] = PAGE_READONLY,
231 [VM_SHARED | VM_WRITE] = PAGE_SHARED,
232 [VM_SHARED | VM_WRITE | VM_READ] = PAGE_SHARED,
233 [VM_SHARED | VM_EXEC] = PAGE_READONLY,
234 [VM_SHARED | VM_EXEC | VM_READ] = PAGE_READONLY,
235 [VM_SHARED | VM_EXEC | VM_WRITE] = PAGE_SHARED,
236 [VM_SHARED | VM_EXEC | VM_WRITE | VM_READ] = PAGE_SHARED
238 DECLARE_VM_GET_PAGE_PROT