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 :
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 :
40 1 : void __init mem_init(void)
41 : {
42 : /* clear the zero-page */
43 1 : 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 1 : brk_end = (unsigned long) UML_ROUND_UP(sbrk(0));
49 2 : map_memory(brk_end, __pa(brk_end), uml_reserved - brk_end, 1, 1, 0);
50 1 : memblock_free((void *)brk_end, uml_reserved - brk_end);
51 1 : uml_reserved = brk_end;
52 :
53 : /* this will put all low memory onto the freelists */
54 1 : memblock_free_all();
55 1 : max_low_pfn = totalram_pages();
56 1 : max_pfn = max_low_pfn;
57 1 : kmalloc_ok = 1;
58 1 : }
59 :
60 : /*
61 : * Create a page table and place a pointer to it in a middle page
62 : * directory entry.
63 : */
64 1 : static void __init one_page_table_init(pmd_t *pmd)
65 : {
66 1 : if (pmd_none(*pmd)) {
67 1 : pte_t *pte = (pte_t *) memblock_alloc_low(PAGE_SIZE,
68 : PAGE_SIZE);
69 1 : if (!pte)
70 0 : panic("%s: Failed to allocate %lu bytes align=%lx\n",
71 : __func__, PAGE_SIZE, PAGE_SIZE);
72 :
73 2 : set_pmd(pmd, __pmd(_KERNPG_TABLE +
74 : (unsigned long) __pa(pte)));
75 1 : BUG_ON(pte != pte_offset_kernel(pmd, 0));
76 : }
77 1 : }
78 :
79 1 : static void __init one_md_table_init(pud_t *pud)
80 : {
81 : #ifdef CONFIG_3_LEVEL_PGTABLES
82 1 : pmd_t *pmd_table = (pmd_t *) memblock_alloc_low(PAGE_SIZE, PAGE_SIZE);
83 1 : if (!pmd_table)
84 0 : panic("%s: Failed to allocate %lu bytes align=%lx\n",
85 : __func__, PAGE_SIZE, PAGE_SIZE);
86 :
87 2 : set_pud(pud, __pud(_KERNPG_TABLE + (unsigned long) __pa(pmd_table)));
88 1 : BUG_ON(pmd_table != pmd_offset(pud, 0));
89 : #endif
90 1 : }
91 :
92 1 : static void __init fixrange_init(unsigned long start, unsigned long end,
93 : pgd_t *pgd_base)
94 : {
95 : pgd_t *pgd;
96 : p4d_t *p4d;
97 : pud_t *pud;
98 : pmd_t *pmd;
99 : int i, j;
100 : unsigned long vaddr;
101 :
102 1 : vaddr = start;
103 1 : i = pgd_index(vaddr);
104 1 : j = pmd_index(vaddr);
105 1 : pgd = pgd_base + i;
106 :
107 2 : for ( ; (i < PTRS_PER_PGD) && (vaddr < end); pgd++, i++) {
108 1 : p4d = p4d_offset(pgd, vaddr);
109 1 : pud = pud_offset(p4d, vaddr);
110 1 : if (pud_none(*pud))
111 1 : one_md_table_init(pud);
112 1 : pmd = pmd_offset(pud, vaddr);
113 2 : for (; (j < PTRS_PER_PMD) && (vaddr < end); pmd++, j++) {
114 1 : one_page_table_init(pmd);
115 1 : vaddr += PMD_SIZE;
116 : }
117 1 : j = 0;
118 : }
119 1 : }
120 :
121 : static void __init fixaddr_user_init( void)
122 : {
123 : #ifdef CONFIG_ARCH_REUSE_HOST_VSYSCALL_AREA
124 : long size = FIXADDR_USER_END - FIXADDR_USER_START;
125 : pte_t *pte;
126 : phys_t p;
127 : unsigned long v, vaddr = FIXADDR_USER_START;
128 :
129 : if (!size)
130 : return;
131 :
132 : fixrange_init( FIXADDR_USER_START, FIXADDR_USER_END, swapper_pg_dir);
133 : v = (unsigned long) memblock_alloc_low(size, PAGE_SIZE);
134 : if (!v)
135 : panic("%s: Failed to allocate %lu bytes align=%lx\n",
136 : __func__, size, PAGE_SIZE);
137 :
138 : memcpy((void *) v , (void *) FIXADDR_USER_START, size);
139 : p = __pa(v);
140 : for ( ; size > 0; size -= PAGE_SIZE, vaddr += PAGE_SIZE,
141 : p += PAGE_SIZE) {
142 : pte = virt_to_kpte(vaddr);
143 : pte_set_val(*pte, p, PAGE_READONLY);
144 : }
145 : #endif
146 : }
147 :
148 1 : void __init paging_init(void)
149 : {
150 1 : unsigned long max_zone_pfn[MAX_NR_ZONES] = { 0 };
151 : unsigned long vaddr;
152 :
153 1 : empty_zero_page = (unsigned long *) memblock_alloc_low(PAGE_SIZE,
154 : PAGE_SIZE);
155 1 : if (!empty_zero_page)
156 0 : panic("%s: Failed to allocate %lu bytes align=%lx\n",
157 : __func__, PAGE_SIZE, PAGE_SIZE);
158 :
159 1 : max_zone_pfn[ZONE_NORMAL] = end_iomem >> PAGE_SHIFT;
160 1 : free_area_init(max_zone_pfn);
161 :
162 : /*
163 : * Fixed mappings, only the page table structure has to be
164 : * created - mappings will be set by set_fixmap():
165 : */
166 1 : vaddr = __fix_to_virt(__end_of_fixed_addresses - 1) & PMD_MASK;
167 1 : fixrange_init(vaddr, FIXADDR_TOP, swapper_pg_dir);
168 :
169 : fixaddr_user_init();
170 1 : }
171 :
172 : /*
173 : * This can't do anything because nothing in the kernel image can be freed
174 : * since it's not in kernel physical memory.
175 : */
176 :
177 0 : void free_initmem(void)
178 : {
179 0 : }
180 :
181 : /* Allocate and free page tables. */
182 :
183 0 : pgd_t *pgd_alloc(struct mm_struct *mm)
184 : {
185 0 : pgd_t *pgd = (pgd_t *)__get_free_page(GFP_KERNEL);
186 :
187 0 : if (pgd) {
188 0 : memset(pgd, 0, USER_PTRS_PER_PGD * sizeof(pgd_t));
189 0 : memcpy(pgd + USER_PTRS_PER_PGD,
190 0 : swapper_pg_dir + USER_PTRS_PER_PGD,
191 0 : (PTRS_PER_PGD - USER_PTRS_PER_PGD) * sizeof(pgd_t));
192 : }
193 0 : return pgd;
194 : }
195 :
196 4 : void *uml_kmalloc(int size, int flags)
197 : {
198 8 : return kmalloc(size, flags);
199 : }
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