1 /*
2 * arch/sh/mm/mmap.c
3 *
4 * Copyright (C) 2008 - 2009 Paul Mundt
5 *
6 * This file is subject to the terms and conditions of the GNU General Public
7 * License. See the file "COPYING" in the main directory of this archive
8 * for more details.
9 */
10 #include <linux/io.h>
11 #include <linux/mm.h>
12 #include <linux/sched/mm.h>
13 #include <linux/mman.h>
14 #include <linux/module.h>
15 #include <asm/page.h>
16 #include <asm/processor.h>
17
18 unsigned long shm_align_mask = PAGE_SIZE - 1; /* Sane caches */
19 EXPORT_SYMBOL(shm_align_mask);
20
21 #ifdef CONFIG_MMU
22 static const pgprot_t protection_map[16] = {
23 [VM_NONE] = PAGE_NONE,
24 [VM_READ] = PAGE_READONLY,
25 [VM_WRITE] = PAGE_COPY,
26 [VM_WRITE | VM_READ] = PAGE_COPY,
27 [VM_EXEC] = PAGE_EXECREAD,
28 [VM_EXEC | VM_READ] = PAGE_EXECREAD,
29 [VM_EXEC | VM_WRITE] = PAGE_COPY,
30 [VM_EXEC | VM_WRITE | VM_READ] = PAGE_COPY,
31 [VM_SHARED] = PAGE_NONE,
32 [VM_SHARED | VM_READ] = PAGE_READONLY,
33 [VM_SHARED | VM_WRITE] = PAGE_WRITEONLY,
34 [VM_SHARED | VM_WRITE | VM_READ] = PAGE_SHARED,
35 [VM_SHARED | VM_EXEC] = PAGE_EXECREAD,
36 [VM_SHARED | VM_EXEC | VM_READ] = PAGE_EXECREAD,
37 [VM_SHARED | VM_EXEC | VM_WRITE] = PAGE_RWX,
38 [VM_SHARED | VM_EXEC | VM_WRITE | VM_READ] = PAGE_RWX
39 };
40 DECLARE_VM_GET_PAGE_PROT
41
42 /*
43 * To avoid cache aliases, we map the shared page with same color.
44 */
45 static inline unsigned long COLOUR_ALIGN(unsigned long addr,
46 unsigned long pgoff)
47 {
48 unsigned long base = (addr + shm_align_mask) & ~shm_align_mask;
49 unsigned long off = (pgoff << PAGE_SHIFT) & shm_align_mask;
50
51 return base + off;
52 }
53
54 unsigned long arch_get_unmapped_area(struct file *filp, unsigned long addr,
55 unsigned long len, unsigned long pgoff, unsigned long flags)
56 {
57 struct mm_struct *mm = current->mm;
58 struct vm_area_struct *vma;
59 int do_colour_align;
60 struct vm_unmapped_area_info info = {};
61
62 if (flags & MAP_FIXED) {
63 /* We do not accept a shared mapping if it would violate
64 * cache aliasing constraints.
65 */
66 if ((flags & MAP_SHARED) &&
67 ((addr - (pgoff << PAGE_SHIFT)) & shm_align_mask))
68 return -EINVAL;
69 return addr;
70 }
71
72 if (unlikely(len > TASK_SIZE))
73 return -ENOMEM;
74
75 do_colour_align = 0;
76 if (filp || (flags & MAP_SHARED))
77 do_colour_align = 1;
78
79 if (addr) {
80 if (do_colour_align)
81 addr = COLOUR_ALIGN(addr, pgoff);
82 else
83 addr = PAGE_ALIGN(addr);
84
85 vma = find_vma(mm, addr);
86 if (TASK_SIZE - len >= addr &&
87 (!vma || addr + len <= vm_start_gap(vma)))
88 return addr;
89 }
90
91 info.length = len;
92 info.low_limit = TASK_UNMAPPED_BASE;
93 info.high_limit = TASK_SIZE;
94 info.align_mask = do_colour_align ? (PAGE_MASK & shm_align_mask) : 0;
95 info.align_offset = pgoff << PAGE_SHIFT;
96 return vm_unmapped_area(&info);
97 }
98
99 unsigned long
100 arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0,
101 const unsigned long len, const unsigned long pgoff,
102 const unsigned long flags)
103 {
104 struct vm_area_struct *vma;
105 struct mm_struct *mm = current->mm;
106 unsigned long addr = addr0;
107 int do_colour_align;
108 struct vm_unmapped_area_info info = {};
109
110 if (flags & MAP_FIXED) {
111 /* We do not accept a shared mapping if it would violate
112 * cache aliasing constraints.
113 */
114 if ((flags & MAP_SHARED) &&
115 ((addr - (pgoff << PAGE_SHIFT)) & shm_align_mask))
116 return -EINVAL;
117 return addr;
118 }
119
120 if (unlikely(len > TASK_SIZE))
121 return -ENOMEM;
122
123 do_colour_align = 0;
124 if (filp || (flags & MAP_SHARED))
125 do_colour_align = 1;
126
127 /* requesting a specific address */
128 if (addr) {
129 if (do_colour_align)
130 addr = COLOUR_ALIGN(addr, pgoff);
131 else
132 addr = PAGE_ALIGN(addr);
133
134 vma = find_vma(mm, addr);
135 if (TASK_SIZE - len >= addr &&
136 (!vma || addr + len <= vm_start_gap(vma)))
137 return addr;
138 }
139
140 info.flags = VM_UNMAPPED_AREA_TOPDOWN;
141 info.length = len;
142 info.low_limit = PAGE_SIZE;
143 info.high_limit = mm->mmap_base;
144 info.align_mask = do_colour_align ? (PAGE_MASK & shm_align_mask) : 0;
145 info.align_offset = pgoff << PAGE_SHIFT;
146 addr = vm_unmapped_area(&info);
147
148 /*
149 * A failed mmap() very likely causes application failure,
150 * so fall back to the bottom-up function here. This scenario
151 * can happen with large stack limits and large mmap()
152 * allocations.
153 */
154 if (addr & ~PAGE_MASK) {
155 VM_BUG_ON(addr != -ENOMEM);
156 info.flags = 0;
157 info.low_limit = TASK_UNMAPPED_BASE;
158 info.high_limit = TASK_SIZE;
159 addr = vm_unmapped_area(&info);
160 }
161
162 return addr;
163 }
164 #endif /* CONFIG_MMU */
165
166 /*
167 * You really shouldn't be using read() or write() on /dev/mem. This
168 * might go away in the future.
169 */
170 int valid_phys_addr_range(phys_addr_t addr, size_t count)
171 {
172 if (addr < __MEMORY_START)
173 return 0;
174 if (addr + count > __pa(high_memory))
175 return 0;
176
177 return 1;
178 }
179
180 int valid_mmap_phys_addr_range(unsigned long pfn, size_t size)
181 {
182 return 1;
183 }
184
Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.