1 | // SPDX-License-Identifier: GPL-2.0 |
2 | /* |
3 | * linux/arch/arm/mm/mmap.c |
4 | */ |
5 | #include <linux/fs.h> |
6 | #include <linux/mm.h> |
7 | #include <linux/mman.h> |
8 | #include <linux/shm.h> |
9 | #include <linux/sched/signal.h> |
10 | #include <linux/sched/mm.h> |
11 | #include <linux/io.h> |
12 | #include <linux/personality.h> |
13 | #include <linux/random.h> |
14 | #include <asm/cachetype.h> |
15 | |
16 | #define COLOUR_ALIGN(addr,pgoff) \ |
17 | ((((addr)+SHMLBA-1)&~(SHMLBA-1)) + \ |
18 | (((pgoff)<<PAGE_SHIFT) & (SHMLBA-1))) |
19 | |
20 | /* |
21 | * We need to ensure that shared mappings are correctly aligned to |
22 | * avoid aliasing issues with VIPT caches. We need to ensure that |
23 | * a specific page of an object is always mapped at a multiple of |
24 | * SHMLBA bytes. |
25 | * |
26 | * We unconditionally provide this function for all cases, however |
27 | * in the VIVT case, we optimise out the alignment rules. |
28 | */ |
29 | unsigned long |
30 | arch_get_unmapped_area(struct file *filp, unsigned long addr, |
31 | unsigned long len, unsigned long pgoff, unsigned long flags) |
32 | { |
33 | struct mm_struct *mm = current->mm; |
34 | struct vm_area_struct *vma; |
35 | int do_align = 0; |
36 | int aliasing = cache_is_vipt_aliasing(); |
37 | struct vm_unmapped_area_info info; |
38 | |
39 | /* |
40 | * We only need to do colour alignment if either the I or D |
41 | * caches alias. |
42 | */ |
43 | if (aliasing) |
44 | do_align = filp || (flags & MAP_SHARED); |
45 | |
46 | /* |
47 | * We enforce the MAP_FIXED case. |
48 | */ |
49 | if (flags & MAP_FIXED) { |
50 | if (aliasing && flags & MAP_SHARED && |
51 | (addr - (pgoff << PAGE_SHIFT)) & (SHMLBA - 1)) |
52 | return -EINVAL; |
53 | return addr; |
54 | } |
55 | |
56 | if (len > TASK_SIZE) |
57 | return -ENOMEM; |
58 | |
59 | if (addr) { |
60 | if (do_align) |
61 | addr = COLOUR_ALIGN(addr, pgoff); |
62 | else |
63 | addr = PAGE_ALIGN(addr); |
64 | |
65 | vma = find_vma(mm, addr); |
66 | if (TASK_SIZE - len >= addr && |
67 | (!vma || addr + len <= vm_start_gap(vma))) |
68 | return addr; |
69 | } |
70 | |
71 | info.flags = 0; |
72 | info.length = len; |
73 | info.low_limit = mm->mmap_base; |
74 | info.high_limit = TASK_SIZE; |
75 | info.align_mask = do_align ? (PAGE_MASK & (SHMLBA - 1)) : 0; |
76 | info.align_offset = pgoff << PAGE_SHIFT; |
77 | return vm_unmapped_area(info: &info); |
78 | } |
79 | |
80 | unsigned long |
81 | arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0, |
82 | const unsigned long len, const unsigned long pgoff, |
83 | const unsigned long flags) |
84 | { |
85 | struct vm_area_struct *vma; |
86 | struct mm_struct *mm = current->mm; |
87 | unsigned long addr = addr0; |
88 | int do_align = 0; |
89 | int aliasing = cache_is_vipt_aliasing(); |
90 | struct vm_unmapped_area_info info; |
91 | |
92 | /* |
93 | * We only need to do colour alignment if either the I or D |
94 | * caches alias. |
95 | */ |
96 | if (aliasing) |
97 | do_align = filp || (flags & MAP_SHARED); |
98 | |
99 | /* requested length too big for entire address space */ |
100 | if (len > TASK_SIZE) |
101 | return -ENOMEM; |
102 | |
103 | if (flags & MAP_FIXED) { |
104 | if (aliasing && flags & MAP_SHARED && |
105 | (addr - (pgoff << PAGE_SHIFT)) & (SHMLBA - 1)) |
106 | return -EINVAL; |
107 | return addr; |
108 | } |
109 | |
110 | /* requesting a specific address */ |
111 | if (addr) { |
112 | if (do_align) |
113 | addr = COLOUR_ALIGN(addr, pgoff); |
114 | else |
115 | addr = PAGE_ALIGN(addr); |
116 | vma = find_vma(mm, addr); |
117 | if (TASK_SIZE - len >= addr && |
118 | (!vma || addr + len <= vm_start_gap(vma))) |
119 | return addr; |
120 | } |
121 | |
122 | info.flags = VM_UNMAPPED_AREA_TOPDOWN; |
123 | info.length = len; |
124 | info.low_limit = FIRST_USER_ADDRESS; |
125 | info.high_limit = mm->mmap_base; |
126 | info.align_mask = do_align ? (PAGE_MASK & (SHMLBA - 1)) : 0; |
127 | info.align_offset = pgoff << PAGE_SHIFT; |
128 | addr = vm_unmapped_area(info: &info); |
129 | |
130 | /* |
131 | * A failed mmap() very likely causes application failure, |
132 | * so fall back to the bottom-up function here. This scenario |
133 | * can happen with large stack limits and large mmap() |
134 | * allocations. |
135 | */ |
136 | if (addr & ~PAGE_MASK) { |
137 | VM_BUG_ON(addr != -ENOMEM); |
138 | info.flags = 0; |
139 | info.low_limit = mm->mmap_base; |
140 | info.high_limit = TASK_SIZE; |
141 | addr = vm_unmapped_area(info: &info); |
142 | } |
143 | |
144 | return addr; |
145 | } |
146 | |
147 | /* |
148 | * You really shouldn't be using read() or write() on /dev/mem. This |
149 | * might go away in the future. |
150 | */ |
151 | int valid_phys_addr_range(phys_addr_t addr, size_t size) |
152 | { |
153 | if (addr < PHYS_OFFSET) |
154 | return 0; |
155 | if (addr + size > __pa(high_memory - 1) + 1) |
156 | return 0; |
157 | |
158 | return 1; |
159 | } |
160 | |
161 | /* |
162 | * Do not allow /dev/mem mappings beyond the supported physical range. |
163 | */ |
164 | int valid_mmap_phys_addr_range(unsigned long pfn, size_t size) |
165 | { |
166 | return (pfn + (size >> PAGE_SHIFT)) <= (1 + (PHYS_MASK >> PAGE_SHIFT)); |
167 | } |
168 | |