1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Copyright (C) 2020-2022 Loongson Technology Corporation Limited
4 */
5 #include <linux/export.h>
6 #include <linux/io.h>
7 #include <linux/kfence.h>
8 #include <linux/memblock.h>
9 #include <linux/mm.h>
10 #include <linux/mman.h>
11
12 #define SHM_ALIGN_MASK (SHMLBA - 1)
13
14 #define COLOUR_ALIGN(addr, pgoff) \
15 ((((addr) + SHM_ALIGN_MASK) & ~SHM_ALIGN_MASK) \
16 + (((pgoff) << PAGE_SHIFT) & SHM_ALIGN_MASK))
17
18 enum mmap_allocation_direction {UP, DOWN};
19
20 static unsigned long arch_get_unmapped_area_common(struct file *filp,
21 unsigned long addr0, unsigned long len, unsigned long pgoff,
22 unsigned long flags, enum mmap_allocation_direction dir)
23 {
24 struct mm_struct *mm = current->mm;
25 struct vm_area_struct *vma;
26 unsigned long addr = addr0;
27 int do_color_align;
28 struct vm_unmapped_area_info info = {};
29
30 if (unlikely(len > TASK_SIZE))
31 return -ENOMEM;
32
33 if (flags & MAP_FIXED) {
34 /* Even MAP_FIXED mappings must reside within TASK_SIZE */
35 if (TASK_SIZE - len < addr)
36 return -EINVAL;
37
38 /*
39 * We do not accept a shared mapping if it would violate
40 * cache aliasing constraints.
41 */
42 if ((flags & MAP_SHARED) &&
43 ((addr - (pgoff << PAGE_SHIFT)) & SHM_ALIGN_MASK))
44 return -EINVAL;
45 return addr;
46 }
47
48 do_color_align = 0;
49 if (filp || (flags & MAP_SHARED))
50 do_color_align = 1;
51
52 /* requesting a specific address */
53 if (addr) {
54 if (do_color_align)
55 addr = COLOUR_ALIGN(addr, pgoff);
56 else
57 addr = PAGE_ALIGN(addr);
58
59 vma = find_vma(mm, addr);
60 if (TASK_SIZE - len >= addr &&
61 (!vma || addr + len <= vm_start_gap(vma)))
62 return addr;
63 }
64
65 info.length = len;
66 info.align_mask = do_color_align ? (PAGE_MASK & SHM_ALIGN_MASK) : 0;
67 info.align_offset = pgoff << PAGE_SHIFT;
68
69 if (dir == DOWN) {
70 info.flags = VM_UNMAPPED_AREA_TOPDOWN;
71 info.low_limit = PAGE_SIZE;
72 info.high_limit = mm->mmap_base;
73 addr = vm_unmapped_area(&info);
74
75 if (!(addr & ~PAGE_MASK))
76 return addr;
77
78 /*
79 * A failed mmap() very likely causes application failure,
80 * so fall back to the bottom-up function here. This scenario
81 * can happen with large stack limits and large mmap()
82 * allocations.
83 */
84 }
85
86 info.low_limit = mm->mmap_base;
87 info.high_limit = TASK_SIZE;
88 return vm_unmapped_area(&info);
89 }
90
91 unsigned long arch_get_unmapped_area(struct file *filp, unsigned long addr0,
92 unsigned long len, unsigned long pgoff, unsigned long flags)
93 {
94 return arch_get_unmapped_area_common(filp,
95 addr0, len, pgoff, flags, UP);
96 }
97
98 /*
99 * There is no need to export this but sched.h declares the function as
100 * extern so making it static here results in an error.
101 */
102 unsigned long arch_get_unmapped_area_topdown(struct file *filp,
103 unsigned long addr0, unsigned long len, unsigned long pgoff,
104 unsigned long flags)
105 {
106 return arch_get_unmapped_area_common(filp,
107 addr0, len, pgoff, flags, DOWN);
108 }
109
110 int __virt_addr_valid(volatile void *kaddr)
111 {
112 unsigned long vaddr = (unsigned long)kaddr;
113
114 if (is_kfence_address((void *)kaddr))
115 return 1;
116
117 if ((vaddr < PAGE_OFFSET) || (vaddr >= vm_map_base))
118 return 0;
119
120 return pfn_valid(PFN_DOWN(PHYSADDR(kaddr)));
121 }
122 EXPORT_SYMBOL_GPL(__virt_addr_valid);
123
124 /*
125 * You really shouldn't be using read() or write() on /dev/mem. This might go
126 * away in the future.
127 */
128 int valid_phys_addr_range(phys_addr_t addr, size_t size)
129 {
130 /*
131 * Check whether addr is covered by a memory region without the
132 * MEMBLOCK_NOMAP attribute, and whether that region covers the
133 * entire range. In theory, this could lead to false negatives
134 * if the range is covered by distinct but adjacent memory regions
135 * that only differ in other attributes. However, few of such
136 * attributes have been defined, and it is debatable whether it
137 * follows that /dev/mem read() calls should be able traverse
138 * such boundaries.
139 */
140 return memblock_is_region_memory(addr, size) && memblock_is_map_memory(addr);
141 }
142
143 /*
144 * Do not allow /dev/mem mappings beyond the supported physical range.
145 */
146 int valid_mmap_phys_addr_range(unsigned long pfn, size_t size)
147 {
148 return !(((pfn << PAGE_SHIFT) + size) & ~(GENMASK_ULL(cpu_pabits, 0)));
149 }
150
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