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
22 /* allocated in paging_init, zeroed in mem_init, and unchanged thereafter */
23 unsigned long *empty_zero_page = NULL;
24 EXPORT_SYMBOL(empty_zero_page);
25
26 /*
27 * Initialized during boot, and readonly for initializing page tables
28 * afterwards
29 */
30 pgd_t swapper_pg_dir[PTRS_PER_PGD];
31
32 /* Initialized at boot time, and readonly after that */
33 unsigned long long highmem;
34 EXPORT_SYMBOL(highmem);
35 int kmalloc_ok = 0;
36
37 /* Used during early boot */
38 static unsigned long brk_end;
39
mem_init(void)40 void __init mem_init(void)
41 {
42 /* clear the zero-page */
43 memset(empty_zero_page, 0, PAGE_SIZE);
44
45 /* Map in the area just after the brk now that kmalloc is about
46 * to be turned on.
47 */
48 brk_end = (unsigned long) UML_ROUND_UP(sbrk(0));
49 map_memory(brk_end, __pa(brk_end), uml_reserved - brk_end, 1, 1, 0);
50 memblock_free(__pa(brk_end), uml_reserved - brk_end);
51 uml_reserved = brk_end;
52
53 /* this will put all low memory onto the freelists */
54 memblock_free_all();
55 max_low_pfn = totalram_pages();
56 max_pfn = max_low_pfn;
57 mem_init_print_info(NULL);
58 kmalloc_ok = 1;
59 }
60
61 /*
62 * Create a page table and place a pointer to it in a middle page
63 * directory entry.
64 */
one_page_table_init(pmd_t * pmd)65 static void __init one_page_table_init(pmd_t *pmd)
66 {
67 if (pmd_none(*pmd)) {
68 pte_t *pte = (pte_t *) memblock_alloc_low(PAGE_SIZE,
69 PAGE_SIZE);
70 if (!pte)
71 panic("%s: Failed to allocate %lu bytes align=%lx\n",
72 __func__, PAGE_SIZE, PAGE_SIZE);
73
74 set_pmd(pmd, __pmd(_KERNPG_TABLE +
75 (unsigned long) __pa(pte)));
76 if (pte != pte_offset_kernel(pmd, 0))
77 BUG();
78 }
79 }
80
one_md_table_init(pud_t * pud)81 static void __init one_md_table_init(pud_t *pud)
82 {
83 #ifdef CONFIG_3_LEVEL_PGTABLES
84 pmd_t *pmd_table = (pmd_t *) memblock_alloc_low(PAGE_SIZE, PAGE_SIZE);
85 if (!pmd_table)
86 panic("%s: Failed to allocate %lu bytes align=%lx\n",
87 __func__, PAGE_SIZE, PAGE_SIZE);
88
89 set_pud(pud, __pud(_KERNPG_TABLE + (unsigned long) __pa(pmd_table)));
90 if (pmd_table != pmd_offset(pud, 0))
91 BUG();
92 #endif
93 }
94
fixrange_init(unsigned long start,unsigned long end,pgd_t * pgd_base)95 static void __init fixrange_init(unsigned long start, unsigned long end,
96 pgd_t *pgd_base)
97 {
98 pgd_t *pgd;
99 p4d_t *p4d;
100 pud_t *pud;
101 pmd_t *pmd;
102 int i, j;
103 unsigned long vaddr;
104
105 vaddr = start;
106 i = pgd_index(vaddr);
107 j = pmd_index(vaddr);
108 pgd = pgd_base + i;
109
110 for ( ; (i < PTRS_PER_PGD) && (vaddr < end); pgd++, i++) {
111 p4d = p4d_offset(pgd, vaddr);
112 pud = pud_offset(p4d, vaddr);
113 if (pud_none(*pud))
114 one_md_table_init(pud);
115 pmd = pmd_offset(pud, vaddr);
116 for (; (j < PTRS_PER_PMD) && (vaddr < end); pmd++, j++) {
117 one_page_table_init(pmd);
118 vaddr += PMD_SIZE;
119 }
120 j = 0;
121 }
122 }
123
fixaddr_user_init(void)124 static void __init fixaddr_user_init( void)
125 {
126 #ifdef CONFIG_ARCH_REUSE_HOST_VSYSCALL_AREA
127 long size = FIXADDR_USER_END - FIXADDR_USER_START;
128 pte_t *pte;
129 phys_t p;
130 unsigned long v, vaddr = FIXADDR_USER_START;
131
132 if (!size)
133 return;
134
135 fixrange_init( FIXADDR_USER_START, FIXADDR_USER_END, swapper_pg_dir);
136 v = (unsigned long) memblock_alloc_low(size, PAGE_SIZE);
137 if (!v)
138 panic("%s: Failed to allocate %lu bytes align=%lx\n",
139 __func__, size, PAGE_SIZE);
140
141 memcpy((void *) v , (void *) FIXADDR_USER_START, size);
142 p = __pa(v);
143 for ( ; size > 0; size -= PAGE_SIZE, vaddr += PAGE_SIZE,
144 p += PAGE_SIZE) {
145 pte = virt_to_kpte(vaddr);
146 pte_set_val(*pte, p, PAGE_READONLY);
147 }
148 #endif
149 }
150
paging_init(void)151 void __init paging_init(void)
152 {
153 unsigned long max_zone_pfn[MAX_NR_ZONES] = { 0 };
154 unsigned long vaddr;
155
156 empty_zero_page = (unsigned long *) memblock_alloc_low(PAGE_SIZE,
157 PAGE_SIZE);
158 if (!empty_zero_page)
159 panic("%s: Failed to allocate %lu bytes align=%lx\n",
160 __func__, PAGE_SIZE, PAGE_SIZE);
161
162 max_zone_pfn[ZONE_NORMAL] = end_iomem >> PAGE_SHIFT;
163 free_area_init(max_zone_pfn);
164
165 /*
166 * Fixed mappings, only the page table structure has to be
167 * created - mappings will be set by set_fixmap():
168 */
169 vaddr = __fix_to_virt(__end_of_fixed_addresses - 1) & PMD_MASK;
170 fixrange_init(vaddr, FIXADDR_TOP, swapper_pg_dir);
171
172 fixaddr_user_init();
173 }
174
175 /*
176 * This can't do anything because nothing in the kernel image can be freed
177 * since it's not in kernel physical memory.
178 */
179
free_initmem(void)180 void free_initmem(void)
181 {
182 }
183
184 /* Allocate and free page tables. */
185
pgd_alloc(struct mm_struct * mm)186 pgd_t *pgd_alloc(struct mm_struct *mm)
187 {
188 pgd_t *pgd = (pgd_t *)__get_free_page(GFP_KERNEL);
189
190 if (pgd) {
191 memset(pgd, 0, USER_PTRS_PER_PGD * sizeof(pgd_t));
192 memcpy(pgd + USER_PTRS_PER_PGD,
193 swapper_pg_dir + USER_PTRS_PER_PGD,
194 (PTRS_PER_PGD - USER_PTRS_PER_PGD) * sizeof(pgd_t));
195 }
196 return pgd;
197 }
198
uml_kmalloc(int size,int flags)199 void *uml_kmalloc(int size, int flags)
200 {
201 return kmalloc(size, flags);
202 }
203
