Line data Source code
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;
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 :
59 1 : void __init mem_init(void)
60 : {
61 : /* clear the zero-page */
62 1 : 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 1 : brk_end = (unsigned long) UML_ROUND_UP(sbrk(0));
68 2 : map_memory(brk_end, __pa(brk_end), uml_reserved - brk_end, 1, 1, 0);
69 1 : memblock_free((void *)brk_end, uml_reserved - brk_end);
70 1 : uml_reserved = brk_end;
71 :
72 : /* this will put all low memory onto the freelists */
73 1 : memblock_free_all();
74 1 : max_low_pfn = totalram_pages();
75 1 : max_pfn = max_low_pfn;
76 1 : kmalloc_ok = 1;
77 1 : }
78 :
79 : /*
80 : * Create a page table and place a pointer to it in a middle page
81 : * directory entry.
82 : */
83 1 : static void __init one_page_table_init(pmd_t *pmd)
84 : {
85 1 : if (pmd_none(*pmd)) {
86 1 : pte_t *pte = (pte_t *) memblock_alloc_low(PAGE_SIZE,
87 : PAGE_SIZE);
88 1 : if (!pte)
89 0 : panic("%s: Failed to allocate %lu bytes align=%lx\n",
90 : __func__, PAGE_SIZE, PAGE_SIZE);
91 :
92 1 : set_pmd(pmd, __pmd(_KERNPG_TABLE +
93 : (unsigned long) __pa(pte)));
94 1 : BUG_ON(pte != pte_offset_kernel(pmd, 0));
95 : }
96 1 : }
97 :
98 1 : static void __init one_md_table_init(pud_t *pud)
99 : {
100 : #ifdef CONFIG_3_LEVEL_PGTABLES
101 1 : pmd_t *pmd_table = (pmd_t *) memblock_alloc_low(PAGE_SIZE, PAGE_SIZE);
102 1 : if (!pmd_table)
103 0 : panic("%s: Failed to allocate %lu bytes align=%lx\n",
104 : __func__, PAGE_SIZE, PAGE_SIZE);
105 :
106 1 : set_pud(pud, __pud(_KERNPG_TABLE + (unsigned long) __pa(pmd_table)));
107 1 : BUG_ON(pmd_table != pmd_offset(pud, 0));
108 : #endif
109 1 : }
110 :
111 1 : 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 1 : vaddr = start;
122 1 : i = pgd_index(vaddr);
123 1 : j = pmd_index(vaddr);
124 1 : pgd = pgd_base + i;
125 :
126 2 : for ( ; (i < PTRS_PER_PGD) && (vaddr < end); pgd++, i++) {
127 1 : p4d = p4d_offset(pgd, vaddr);
128 1 : pud = pud_offset(p4d, vaddr);
129 1 : if (pud_none(*pud))
130 1 : one_md_table_init(pud);
131 1 : pmd = pmd_offset(pud, vaddr);
132 2 : for (; (j < PTRS_PER_PMD) && (vaddr < end); pmd++, j++) {
133 1 : one_page_table_init(pmd);
134 1 : vaddr += PMD_SIZE;
135 : }
136 1 : j = 0;
137 : }
138 1 : }
139 :
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 :
167 1 : void __init paging_init(void)
168 : {
169 1 : unsigned long max_zone_pfn[MAX_NR_ZONES] = { 0 };
170 : unsigned long vaddr;
171 :
172 1 : empty_zero_page = (unsigned long *) memblock_alloc_low(PAGE_SIZE,
173 : PAGE_SIZE);
174 1 : if (!empty_zero_page)
175 0 : panic("%s: Failed to allocate %lu bytes align=%lx\n",
176 : __func__, PAGE_SIZE, PAGE_SIZE);
177 :
178 1 : max_zone_pfn[ZONE_NORMAL] = end_iomem >> PAGE_SHIFT;
179 1 : 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 1 : vaddr = __fix_to_virt(__end_of_fixed_addresses - 1) & PMD_MASK;
186 1 : fixrange_init(vaddr, FIXADDR_TOP, swapper_pg_dir);
187 :
188 : fixaddr_user_init();
189 1 : }
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 :
196 0 : void free_initmem(void)
197 : {
198 0 : }
199 :
200 : /* Allocate and free page tables. */
201 :
202 0 : pgd_t *pgd_alloc(struct mm_struct *mm)
203 : {
204 0 : pgd_t *pgd = (pgd_t *)__get_free_page(GFP_KERNEL);
205 :
206 0 : if (pgd) {
207 0 : memset(pgd, 0, USER_PTRS_PER_PGD * sizeof(pgd_t));
208 0 : memcpy(pgd + USER_PTRS_PER_PGD,
209 0 : swapper_pg_dir + USER_PTRS_PER_PGD,
210 0 : (PTRS_PER_PGD - USER_PTRS_PER_PGD) * sizeof(pgd_t));
211 : }
212 0 : return pgd;
213 : }
214 :
215 4 : void *uml_kmalloc(int size, int flags)
216 : {
217 8 : 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 0 : DECLARE_VM_GET_PAGE_PROT
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