summaryrefslogtreecommitdiffstats
path: root/arch/um/kernel/mem.c
blob: 0039771eb01cd40f9bb163bedf5f914b95bdea5b (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
 */

#include <linux/stddef.h>
#include <linux/module.h>
#include <linux/memblock.h>
#include <linux/highmem.h>
#include <linux/mm.h>
#include <linux/swap.h>
#include <linux/slab.h>
#include <asm/fixmap.h>
#include <asm/page.h>
#include <as-layout.h>
#include <init.h>
#include <kern.h>
#include <kern_util.h>
#include <mem_user.h>
#include <os.h>

/* allocated in paging_init, zeroed in mem_init, and unchanged thereafter */
unsigned long *empty_zero_page = NULL;
EXPORT_SYMBOL(empty_zero_page);

/*
 * Initialized during boot, and readonly for initializing page tables
 * afterwards
 */
pgd_t swapper_pg_dir[PTRS_PER_PGD];

/* Initialized at boot time, and readonly after that */
unsigned long long highmem;
EXPORT_SYMBOL(highmem);
int kmalloc_ok = 0;

/* Used during early boot */
static unsigned long brk_end;

void __init mem_init(void)
{
	/* clear the zero-page */
	memset(empty_zero_page, 0, PAGE_SIZE);

	/* Map in the area just after the brk now that kmalloc is about
	 * to be turned on.
	 */
	brk_end = (unsigned long) UML_ROUND_UP(sbrk(0));
	map_memory(brk_end, __pa(brk_end), uml_reserved - brk_end, 1, 1, 0);
	memblock_free((void *)brk_end, uml_reserved - brk_end);
	uml_reserved = brk_end;

	/* this will put all low memory onto the freelists */
	memblock_free_all();
	max_low_pfn = totalram_pages();
	max_pfn = max_low_pfn;
	kmalloc_ok = 1;
}

/*
 * Create a page table and place a pointer to it in a middle page
 * directory entry.
 */
static void __init one_page_table_init(pmd_t *pmd)
{
	if (pmd_none(*pmd)) {
		pte_t *pte = (pte_t *) memblock_alloc_low(PAGE_SIZE,
							  PAGE_SIZE);
		if (!pte)
			panic("%s: Failed to allocate %lu bytes align=%lx\n",
			      __func__, PAGE_SIZE, PAGE_SIZE);

		set_pmd(pmd, __pmd(_KERNPG_TABLE +
					   (unsigned long) __pa(pte)));
		BUG_ON(pte != pte_offset_kernel(pmd, 0));
	}
}

static void __init one_md_table_init(pud_t *pud)
{
#ifdef CONFIG_3_LEVEL_PGTABLES
	pmd_t *pmd_table = (pmd_t *) memblock_alloc_low(PAGE_SIZE, PAGE_SIZE);
	if (!pmd_table)
		panic("%s: Failed to allocate %lu bytes align=%lx\n",
		      __func__, PAGE_SIZE, PAGE_SIZE);

	set_pud(pud, __pud(_KERNPG_TABLE + (unsigned long) __pa(pmd_table)));
	if (pmd_table != pmd_offset(pud, 0))
		BUG();
#endif
}

static void __init fixrange_init(unsigned long start, unsigned long end,
				 pgd_t *pgd_base)
{
	pgd_t *pgd;
	p4d_t *p4d;
	pud_t *pud;
	pmd_t *pmd;
	int i, j;
	unsigned long vaddr;

	vaddr = start;
	i = pgd_index(vaddr);
	j = pmd_index(vaddr);
	pgd = pgd_base + i;

	for ( ; (i < PTRS_PER_PGD) && (vaddr < end); pgd++, i++) {
		p4d = p4d_offset(pgd, vaddr);
		pud = pud_offset(p4d, vaddr);
		if (pud_none(*pud))
			one_md_table_init(pud);
		pmd = pmd_offset(pud, vaddr);
		for (; (j < PTRS_PER_PMD) && (vaddr < end); pmd++, j++) {
			one_page_table_init(pmd);
			vaddr += PMD_SIZE;
		}
		j = 0;
	}
}

static void __init fixaddr_user_init( void)
{
#ifdef CONFIG_ARCH_REUSE_HOST_VSYSCALL_AREA
	long size = FIXADDR_USER_END - FIXADDR_USER_START;
	pte_t *pte;
	phys_t p;
	unsigned long v, vaddr = FIXADDR_USER_START;

	if (!size)
		return;

	fixrange_init( FIXADDR_USER_START, FIXADDR_USER_END, swapper_pg_dir);
	v = (unsigned long) memblock_alloc_low(size, PAGE_SIZE);
	if (!v)
		panic("%s: Failed to allocate %lu bytes align=%lx\n",
		      __func__, size, PAGE_SIZE);

	memcpy((void *) v , (void *) FIXADDR_USER_START, size);
	p = __pa(v);
	for ( ; size > 0; size -= PAGE_SIZE, vaddr += PAGE_SIZE,
		      p += PAGE_SIZE) {
		pte = virt_to_kpte(vaddr);
		pte_set_val(*pte, p, PAGE_READONLY);
	}
#endif
}

void __init paging_init(void)
{
	unsigned long max_zone_pfn[MAX_NR_ZONES] = { 0 };
	unsigned long vaddr;

	empty_zero_page = (unsigned long *) memblock_alloc_low(PAGE_SIZE,
							       PAGE_SIZE);
	if (!empty_zero_page)
		panic("%s: Failed to allocate %lu bytes align=%lx\n",
		      __func__, PAGE_SIZE, PAGE_SIZE);

	max_zone_pfn[ZONE_NORMAL] = end_iomem >> PAGE_SHIFT;
	free_area_init(max_zone_pfn);

	/*
	 * Fixed mappings, only the page table structure has to be
	 * created - mappings will be set by set_fixmap():
	 */
	vaddr = __fix_to_virt(__end_of_fixed_addresses - 1) & PMD_MASK;
	fixrange_init(vaddr, FIXADDR_TOP, swapper_pg_dir);

	fixaddr_user_init();
}

/*
 * This can't do anything because nothing in the kernel image can be freed
 * since it's not in kernel physical memory.
 */

void free_initmem(void)
{
}

/* Allocate and free page tables. */

pgd_t *pgd_alloc(struct mm_struct *mm)
{
	pgd_t *pgd = (pgd_t *)__get_free_page(GFP_KERNEL);

	if (pgd) {
		memset(pgd, 0, USER_PTRS_PER_PGD * sizeof(pgd_t));
		memcpy(pgd + USER_PTRS_PER_PGD,
		       swapper_pg_dir + USER_PTRS_PER_PGD,
		       (PTRS_PER_PGD - USER_PTRS_PER_PGD) * sizeof(pgd_t));
	}
	return pgd;
}

void *uml_kmalloc(int size, int flags)
{
	return kmalloc(size, flags);
}