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 #include <linux/sched/task.h>
22
23 #ifdef CONFIG_KASAN
24 int kasan_um_is_ready;
kasan_init(void)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 unsigned long long highmem;
53 EXPORT_SYMBOL(highmem);
54 int kmalloc_ok = 0;
55
56 /* Used during early boot */
57 static unsigned long brk_end;
58
mem_init(void)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_low_pfn = totalram_pages();
75 max_pfn = max_low_pfn;
76 kmalloc_ok = 1;
77 }
78
79 /*
80 * Create a page table and place a pointer to it in a middle page
81 * directory entry.
82 */
one_page_table_init(pmd_t * pmd)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
one_md_table_init(pud_t * pud)98 static void __init one_md_table_init(pud_t *pud)
99 {
100 #ifdef CONFIG_3_LEVEL_PGTABLES
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
fixrange_init(unsigned long start,unsigned long end,pgd_t * pgd_base)111 static void __init fixrange_init(unsigned long start, unsigned long end,
112 pgd_t *pgd_base)
113 {
114 pgd_t *pgd;
115 p4d_t *p4d;
116 pud_t *pud;
117 pmd_t *pmd;
118 int i, j;
119 unsigned long vaddr;
120
121 vaddr = start;
122 i = pgd_index(vaddr);
123 j = pmd_index(vaddr);
124 pgd = pgd_base + i;
125
126 for ( ; (i < PTRS_PER_PGD) && (vaddr < end); pgd++, i++) {
127 p4d = p4d_offset(pgd, vaddr);
128 pud = pud_offset(p4d, vaddr);
129 if (pud_none(*pud))
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);
134 vaddr += PMD_SIZE;
135 }
136 j = 0;
137 }
138 }
139
fixaddr_user_init(void)140 static void __init fixaddr_user_init( void)
141 {
142 #ifdef CONFIG_ARCH_REUSE_HOST_VSYSCALL_AREA
143 long size = FIXADDR_USER_END - FIXADDR_USER_START;
144 pte_t *pte;
145 phys_t p;
146 unsigned long v, vaddr = FIXADDR_USER_START;
147
148 if (!size)
149 return;
150
151 fixrange_init( FIXADDR_USER_START, FIXADDR_USER_END, swapper_pg_dir);
152 v = (unsigned long) memblock_alloc_low(size, PAGE_SIZE);
153 if (!v)
154 panic("%s: Failed to allocate %lu bytes align=%lx\n",
155 __func__, size, PAGE_SIZE);
156
157 memcpy((void *) v , (void *) FIXADDR_USER_START, size);
158 p = __pa(v);
159 for ( ; size > 0; size -= PAGE_SIZE, vaddr += PAGE_SIZE,
160 p += PAGE_SIZE) {
161 pte = virt_to_kpte(vaddr);
162 pte_set_val(*pte, p, PAGE_READONLY);
163 }
164 #endif
165 }
166
paging_init(void)167 void __init paging_init(void)
168 {
169 unsigned long max_zone_pfn[MAX_NR_ZONES] = { 0 };
170 unsigned long vaddr;
171
172 empty_zero_page = (unsigned long *) memblock_alloc_low(PAGE_SIZE,
173 PAGE_SIZE);
174 if (!empty_zero_page)
175 panic("%s: Failed to allocate %lu bytes align=%lx\n",
176 __func__, PAGE_SIZE, PAGE_SIZE);
177
178 max_zone_pfn[ZONE_NORMAL] = end_iomem >> PAGE_SHIFT;
179 free_area_init(max_zone_pfn);
180
181 /*
182 * Fixed mappings, only the page table structure has to be
183 * created - mappings will be set by set_fixmap():
184 */
185 vaddr = __fix_to_virt(__end_of_fixed_addresses - 1) & PMD_MASK;
186 fixrange_init(vaddr, FIXADDR_TOP, swapper_pg_dir);
187
188 fixaddr_user_init();
189 }
190
191 /*
192 * This can't do anything because nothing in the kernel image can be freed
193 * since it's not in kernel physical memory.
194 */
195
free_initmem(void)196 void free_initmem(void)
197 {
198 }
199
200 /* Allocate and free page tables. */
201
pgd_alloc(struct mm_struct * mm)202 pgd_t *pgd_alloc(struct mm_struct *mm)
203 {
204 pgd_t *pgd = (pgd_t *)__get_free_page(GFP_KERNEL);
205
206 if (pgd) {
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));
211 }
212 return pgd;
213 }
214
uml_kmalloc(int size,int flags)215 void *uml_kmalloc(int size, int flags)
216 {
217 return kmalloc(size, flags);
218 }
219
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
237 };
238 DECLARE_VM_GET_PAGE_PROT
239