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 <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;
kasan_init(void)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 unsigned long long highmem;
55 EXPORT_SYMBOL(highmem);
56 int kmalloc_ok = 0;
57
58 /* Used during early boot */
59 static unsigned long brk_end;
60
mem_init(void)61 void __init mem_init(void)
62 {
63 /* clear the zero-page */
64 memset(empty_zero_page, 0, PAGE_SIZE);
65
66 /* Map in the area just after the brk now that kmalloc is about
67 * to be turned on.
68 */
69 brk_end = (unsigned long) UML_ROUND_UP(sbrk(0));
70 map_memory(brk_end, __pa(brk_end), uml_reserved - brk_end, 1, 1, 0);
71 memblock_free((void *)brk_end, uml_reserved - brk_end);
72 uml_reserved = brk_end;
73
74 /* this will put all low memory onto the freelists */
75 memblock_free_all();
76 max_low_pfn = totalram_pages();
77 max_pfn = max_low_pfn;
78 kmalloc_ok = 1;
79 }
80
81 /*
82 * Create a page table and place a pointer to it in a middle page
83 * directory entry.
84 */
one_page_table_init(pmd_t * pmd)85 static void __init one_page_table_init(pmd_t *pmd)
86 {
87 if (pmd_none(*pmd)) {
88 pte_t *pte = (pte_t *) memblock_alloc_low(PAGE_SIZE,
89 PAGE_SIZE);
90 if (!pte)
91 panic("%s: Failed to allocate %lu bytes align=%lx\n",
92 __func__, PAGE_SIZE, PAGE_SIZE);
93
94 set_pmd(pmd, __pmd(_KERNPG_TABLE +
95 (unsigned long) __pa(pte)));
96 BUG_ON(pte != pte_offset_kernel(pmd, 0));
97 }
98 }
99
one_md_table_init(pud_t * pud)100 static void __init one_md_table_init(pud_t *pud)
101 {
102 #ifdef CONFIG_3_LEVEL_PGTABLES
103 pmd_t *pmd_table = (pmd_t *) memblock_alloc_low(PAGE_SIZE, PAGE_SIZE);
104 if (!pmd_table)
105 panic("%s: Failed to allocate %lu bytes align=%lx\n",
106 __func__, PAGE_SIZE, PAGE_SIZE);
107
108 set_pud(pud, __pud(_KERNPG_TABLE + (unsigned long) __pa(pmd_table)));
109 BUG_ON(pmd_table != pmd_offset(pud, 0));
110 #endif
111 }
112
fixrange_init(unsigned long start,unsigned long end,pgd_t * pgd_base)113 static void __init fixrange_init(unsigned long start, unsigned long end,
114 pgd_t *pgd_base)
115 {
116 pgd_t *pgd;
117 p4d_t *p4d;
118 pud_t *pud;
119 pmd_t *pmd;
120 int i, j;
121 unsigned long vaddr;
122
123 vaddr = start;
124 i = pgd_index(vaddr);
125 j = pmd_index(vaddr);
126 pgd = pgd_base + i;
127
128 for ( ; (i < PTRS_PER_PGD) && (vaddr < end); pgd++, i++) {
129 p4d = p4d_offset(pgd, vaddr);
130 pud = pud_offset(p4d, vaddr);
131 if (pud_none(*pud))
132 one_md_table_init(pud);
133 pmd = pmd_offset(pud, vaddr);
134 for (; (j < PTRS_PER_PMD) && (vaddr < end); pmd++, j++) {
135 one_page_table_init(pmd);
136 vaddr += PMD_SIZE;
137 }
138 j = 0;
139 }
140 }
141
fixaddr_user_init(void)142 static void __init fixaddr_user_init( void)
143 {
144 #ifdef CONFIG_ARCH_REUSE_HOST_VSYSCALL_AREA
145 long size = FIXADDR_USER_END - FIXADDR_USER_START;
146 pte_t *pte;
147 phys_t p;
148 unsigned long v, vaddr = FIXADDR_USER_START;
149
150 if (!size)
151 return;
152
153 fixrange_init( FIXADDR_USER_START, FIXADDR_USER_END, swapper_pg_dir);
154 v = (unsigned long) memblock_alloc_low(size, PAGE_SIZE);
155 if (!v)
156 panic("%s: Failed to allocate %lu bytes align=%lx\n",
157 __func__, size, PAGE_SIZE);
158
159 memcpy((void *) v , (void *) FIXADDR_USER_START, size);
160 p = __pa(v);
161 for ( ; size > 0; size -= PAGE_SIZE, vaddr += PAGE_SIZE,
162 p += PAGE_SIZE) {
163 pte = virt_to_kpte(vaddr);
164 pte_set_val(*pte, p, PAGE_READONLY);
165 }
166 #endif
167 }
168
paging_init(void)169 void __init paging_init(void)
170 {
171 unsigned long max_zone_pfn[MAX_NR_ZONES] = { 0 };
172 unsigned long vaddr;
173
174 empty_zero_page = (unsigned long *) memblock_alloc_low(PAGE_SIZE,
175 PAGE_SIZE);
176 if (!empty_zero_page)
177 panic("%s: Failed to allocate %lu bytes align=%lx\n",
178 __func__, PAGE_SIZE, PAGE_SIZE);
179
180 max_zone_pfn[ZONE_NORMAL] = end_iomem >> PAGE_SHIFT;
181 free_area_init(max_zone_pfn);
182
183 /*
184 * Fixed mappings, only the page table structure has to be
185 * created - mappings will be set by set_fixmap():
186 */
187 vaddr = __fix_to_virt(__end_of_fixed_addresses - 1) & PMD_MASK;
188 fixrange_init(vaddr, FIXADDR_TOP, swapper_pg_dir);
189
190 fixaddr_user_init();
191 }
192
193 /*
194 * This can't do anything because nothing in the kernel image can be freed
195 * since it's not in kernel physical memory.
196 */
197
free_initmem(void)198 void free_initmem(void)
199 {
200 }
201
202 /* Allocate and free page tables. */
203
pgd_alloc(struct mm_struct * mm)204 pgd_t *pgd_alloc(struct mm_struct *mm)
205 {
206 pgd_t *pgd = (pgd_t *)__get_free_page(GFP_KERNEL);
207
208 if (pgd) {
209 memset(pgd, 0, USER_PTRS_PER_PGD * sizeof(pgd_t));
210 memcpy(pgd + USER_PTRS_PER_PGD,
211 swapper_pg_dir + USER_PTRS_PER_PGD,
212 (PTRS_PER_PGD - USER_PTRS_PER_PGD) * sizeof(pgd_t));
213 }
214 return pgd;
215 }
216
uml_kmalloc(int size,int flags)217 void *uml_kmalloc(int size, int flags)
218 {
219 return kmalloc(size, flags);
220 }
221
222 static const pgprot_t protection_map[16] = {
223 [VM_NONE] = PAGE_NONE,
224 [VM_READ] = PAGE_READONLY,
225 [VM_WRITE] = PAGE_COPY,
226 [VM_WRITE | VM_READ] = PAGE_COPY,
227 [VM_EXEC] = PAGE_READONLY,
228 [VM_EXEC | VM_READ] = PAGE_READONLY,
229 [VM_EXEC | VM_WRITE] = PAGE_COPY,
230 [VM_EXEC | VM_WRITE | VM_READ] = PAGE_COPY,
231 [VM_SHARED] = PAGE_NONE,
232 [VM_SHARED | VM_READ] = PAGE_READONLY,
233 [VM_SHARED | VM_WRITE] = PAGE_SHARED,
234 [VM_SHARED | VM_WRITE | VM_READ] = PAGE_SHARED,
235 [VM_SHARED | VM_EXEC] = PAGE_READONLY,
236 [VM_SHARED | VM_EXEC | VM_READ] = PAGE_READONLY,
237 [VM_SHARED | VM_EXEC | VM_WRITE] = PAGE_SHARED,
238 [VM_SHARED | VM_EXEC | VM_WRITE | VM_READ] = PAGE_SHARED
239 };
240 DECLARE_VM_GET_PAGE_PROT
241