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/mm.h>
10 #include <linux/swap.h>
11 #include <linux/slab.h>
12 #include <linux/init.h>
13 #include <asm/sections.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 int kmalloc_ok = 0;
55
56 /* Used during early boot */
57 static unsigned long brk_end;
58
arch_mm_preinit(void)59 void __init arch_mm_preinit(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 min_low_pfn = PFN_UP(__pa(uml_reserved));
72 max_pfn = max_low_pfn;
73 }
74
mem_init(void)75 void __init mem_init(void)
76 {
77 kmalloc_ok = 1;
78 }
79
80 #if IS_ENABLED(CONFIG_ARCH_REUSE_HOST_VSYSCALL_AREA)
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 #if CONFIG_PGTABLE_LEVELS > 2
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
one_ud_table_init(p4d_t * p4d)113 static void __init one_ud_table_init(p4d_t *p4d)
114 {
115 #if CONFIG_PGTABLE_LEVELS > 3
116 pud_t *pud_table = (pud_t *) memblock_alloc_low(PAGE_SIZE, PAGE_SIZE);
117 if (!pud_table)
118 panic("%s: Failed to allocate %lu bytes align=%lx\n",
119 __func__, PAGE_SIZE, PAGE_SIZE);
120
121 set_p4d(p4d, __p4d(_KERNPG_TABLE + (unsigned long) __pa(pud_table)));
122 BUG_ON(pud_table != pud_offset(p4d, 0));
123 #endif
124 }
125
fixrange_init(unsigned long start,unsigned long end,pgd_t * pgd_base)126 static void __init fixrange_init(unsigned long start, unsigned long end,
127 pgd_t *pgd_base)
128 {
129 pgd_t *pgd;
130 p4d_t *p4d;
131 pud_t *pud;
132 pmd_t *pmd;
133 int i, j;
134 unsigned long vaddr;
135
136 vaddr = start;
137 i = pgd_index(vaddr);
138 j = pmd_index(vaddr);
139 pgd = pgd_base + i;
140
141 for ( ; (i < PTRS_PER_PGD) && (vaddr < end); pgd++, i++) {
142 p4d = p4d_offset(pgd, vaddr);
143 if (p4d_none(*p4d))
144 one_ud_table_init(p4d);
145 pud = pud_offset(p4d, vaddr);
146 if (pud_none(*pud))
147 one_md_table_init(pud);
148 pmd = pmd_offset(pud, vaddr);
149 for (; (j < PTRS_PER_PMD) && (vaddr < end); pmd++, j++) {
150 one_page_table_init(pmd);
151 vaddr += PMD_SIZE;
152 }
153 j = 0;
154 }
155 }
156
fixaddr_user_init(void)157 static void __init fixaddr_user_init( void)
158 {
159 long size = FIXADDR_USER_END - FIXADDR_USER_START;
160 pte_t *pte;
161 phys_t p;
162 unsigned long v, vaddr = FIXADDR_USER_START;
163
164 if (!size)
165 return;
166
167 fixrange_init( FIXADDR_USER_START, FIXADDR_USER_END, swapper_pg_dir);
168 v = (unsigned long) memblock_alloc_low(size, PAGE_SIZE);
169 if (!v)
170 panic("%s: Failed to allocate %lu bytes align=%lx\n",
171 __func__, size, PAGE_SIZE);
172
173 memcpy((void *) v , (void *) FIXADDR_USER_START, size);
174 p = __pa(v);
175 for ( ; size > 0; size -= PAGE_SIZE, vaddr += PAGE_SIZE,
176 p += PAGE_SIZE) {
177 pte = virt_to_kpte(vaddr);
178 pte_set_val(*pte, p, PAGE_READONLY);
179 }
180 }
181 #endif
182
paging_init(void)183 void __init paging_init(void)
184 {
185 unsigned long max_zone_pfn[MAX_NR_ZONES] = { 0 };
186
187 empty_zero_page = (unsigned long *) memblock_alloc_low(PAGE_SIZE,
188 PAGE_SIZE);
189 if (!empty_zero_page)
190 panic("%s: Failed to allocate %lu bytes align=%lx\n",
191 __func__, PAGE_SIZE, PAGE_SIZE);
192
193 max_zone_pfn[ZONE_NORMAL] = end_iomem >> PAGE_SHIFT;
194 free_area_init(max_zone_pfn);
195
196 #if IS_ENABLED(CONFIG_ARCH_REUSE_HOST_VSYSCALL_AREA)
197 fixaddr_user_init();
198 #endif
199 }
200
201 /*
202 * This can't do anything because nothing in the kernel image can be freed
203 * since it's not in kernel physical memory.
204 */
205
free_initmem(void)206 void free_initmem(void)
207 {
208 }
209
210 /* Allocate and free page tables. */
211
pgd_alloc(struct mm_struct * mm)212 pgd_t *pgd_alloc(struct mm_struct *mm)
213 {
214 pgd_t *pgd = __pgd_alloc(mm, 0);
215
216 if (pgd)
217 memcpy(pgd + USER_PTRS_PER_PGD,
218 swapper_pg_dir + USER_PTRS_PER_PGD,
219 (PTRS_PER_PGD - USER_PTRS_PER_PGD) * sizeof(pgd_t));
220
221 return pgd;
222 }
223
uml_kmalloc(int size,int flags)224 void *uml_kmalloc(int size, int flags)
225 {
226 return kmalloc(size, flags);
227 }
228
229 static const pgprot_t protection_map[16] = {
230 [VM_NONE] = PAGE_NONE,
231 [VM_READ] = PAGE_READONLY,
232 [VM_WRITE] = PAGE_COPY,
233 [VM_WRITE | VM_READ] = PAGE_COPY,
234 [VM_EXEC] = PAGE_READONLY,
235 [VM_EXEC | VM_READ] = PAGE_READONLY,
236 [VM_EXEC | VM_WRITE] = PAGE_COPY,
237 [VM_EXEC | VM_WRITE | VM_READ] = PAGE_COPY,
238 [VM_SHARED] = PAGE_NONE,
239 [VM_SHARED | VM_READ] = PAGE_READONLY,
240 [VM_SHARED | VM_WRITE] = PAGE_SHARED,
241 [VM_SHARED | VM_WRITE | VM_READ] = PAGE_SHARED,
242 [VM_SHARED | VM_EXEC] = PAGE_READONLY,
243 [VM_SHARED | VM_EXEC | VM_READ] = PAGE_READONLY,
244 [VM_SHARED | VM_EXEC | VM_WRITE] = PAGE_SHARED,
245 [VM_SHARED | VM_EXEC | VM_WRITE | VM_READ] = PAGE_SHARED
246 };
247 DECLARE_VM_GET_PAGE_PROT
248
mark_rodata_ro(void)249 void mark_rodata_ro(void)
250 {
251 unsigned long rodata_start = PFN_ALIGN(__start_rodata);
252 unsigned long rodata_end = PFN_ALIGN(__end_rodata);
253
254 os_protect_memory((void *)rodata_start, rodata_end - rodata_start, 1, 0, 0);
255 }
256