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139 lines · 3.4 KiB

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#include <linux/kasan.h>
25
26#ifdef CONFIG_KASAN
27void __init 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 /*
36 * Since kasan_init() is called before main(),
37 * KASAN is initialized but the enablement is deferred after
38 * jump_label_init(). See arch_mm_preinit().
39 */
40}
41
42static void (*kasan_init_ptr)(void)
43__section(".kasan_init") __used
44= kasan_init;
45#endif
46
47/*
48 * Initialized during boot, and readonly for initializing page tables
49 * afterwards
50 */
51pgd_t swapper_pg_dir[PTRS_PER_PGD];
52
53/* Initialized at boot time, and readonly after that */
54int kmalloc_ok = 0;
55
56/* Used during early boot */
57static unsigned long brk_end;
58
59void __init arch_mm_preinit(void)
60{
61 /* Safe to call after jump_label_init(). Enables KASAN. */
62 kasan_init_generic();
63
64 /* Map in the area just after the brk now that kmalloc is about
65 * to be turned on.
66 */
67 brk_end = PAGE_ALIGN((unsigned long) 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
75void __init mem_init(void)
76{
77 kmalloc_ok = 1;
78}
79
80void __init arch_zone_limits_init(unsigned long *max_zone_pfns)
81{
82 max_zone_pfns[ZONE_NORMAL] = high_physmem >> PAGE_SHIFT;
83}
84
85/*
86 * This can't do anything because nothing in the kernel image can be freed
87 * since it's not in kernel physical memory.
88 */
89
90void free_initmem(void)
91{
92}
93
94/* Allocate and free page tables. */
95
96pgd_t *pgd_alloc(struct mm_struct *mm)
97{
98 pgd_t *pgd = __pgd_alloc(mm, 0);
99
100 if (pgd)
101 memcpy(pgd + USER_PTRS_PER_PGD,
102 swapper_pg_dir + USER_PTRS_PER_PGD,
103 (PTRS_PER_PGD - USER_PTRS_PER_PGD) * sizeof(pgd_t));
104
105 return pgd;
106}
107
108void *uml_kmalloc(int size, int flags)
109{
110 return kmalloc(size, flags);
111}
112
113static const pgprot_t protection_map[16] = {
114 [VM_NONE] = PAGE_NONE,
115 [VM_READ] = PAGE_READONLY,
116 [VM_WRITE] = PAGE_COPY,
117 [VM_WRITE | VM_READ] = PAGE_COPY,
118 [VM_EXEC] = PAGE_READONLY,
119 [VM_EXEC | VM_READ] = PAGE_READONLY,
120 [VM_EXEC | VM_WRITE] = PAGE_COPY,
121 [VM_EXEC | VM_WRITE | VM_READ] = PAGE_COPY,
122 [VM_SHARED] = PAGE_NONE,
123 [VM_SHARED | VM_READ] = PAGE_READONLY,
124 [VM_SHARED | VM_WRITE] = PAGE_SHARED,
125 [VM_SHARED | VM_WRITE | VM_READ] = PAGE_SHARED,
126 [VM_SHARED | VM_EXEC] = PAGE_READONLY,
127 [VM_SHARED | VM_EXEC | VM_READ] = PAGE_READONLY,
128 [VM_SHARED | VM_EXEC | VM_WRITE] = PAGE_SHARED,
129 [VM_SHARED | VM_EXEC | VM_WRITE | VM_READ] = PAGE_SHARED
130};
131DECLARE_VM_GET_PAGE_PROT
132
133void mark_rodata_ro(void)
134{
135 unsigned long rodata_start = PFN_ALIGN(__start_rodata);
136 unsigned long rodata_end = PFN_ALIGN(__end_rodata);
137
138 os_protect_memory((void *)rodata_start, rodata_end - rodata_start, 1, 0, 0);
139}