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
18unsigned long shm_align_mask = PAGE_SIZE - 1; /* Sane caches */
19EXPORT_SYMBOL(shm_align_mask);
20
21#ifdef CONFIG_MMU
22static 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};
40DECLARE_VM_GET_PAGE_PROT
41
42/*
43 * To avoid cache aliases, we map the shared page with same color.
44 */
45static 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
54unsigned long arch_get_unmapped_area(struct file *filp, unsigned long addr,
55 unsigned long len, unsigned long pgoff, unsigned long flags,
56 vm_flags_t vm_flags)
57{
58 struct mm_struct *mm = current->mm;
59 struct vm_area_struct *vma;
60 int do_colour_align;
61 struct vm_unmapped_area_info info = {};
62
63 if (flags & MAP_FIXED) {
64 /* We do not accept a shared mapping if it would violate
65 * cache aliasing constraints.
66 */
67 if ((flags & MAP_SHARED) &&
68 ((addr - (pgoff << PAGE_SHIFT)) & shm_align_mask))
69 return -EINVAL;
70 return addr;
71 }
72
73 if (unlikely(len > TASK_SIZE))
74 return -ENOMEM;
75
76 do_colour_align = 0;
77 if (filp || (flags & MAP_SHARED))
78 do_colour_align = 1;
79
80 if (addr) {
81 if (do_colour_align)
82 addr = COLOUR_ALIGN(addr, pgoff);
83 else
84 addr = PAGE_ALIGN(addr);
85
86 vma = find_vma(mm, addr);
87 if (TASK_SIZE - len >= addr &&
88 (!vma || addr + len <= vm_start_gap(vma)))
89 return addr;
90 }
91
92 info.length = len;
93 info.low_limit = TASK_UNMAPPED_BASE;
94 info.high_limit = TASK_SIZE;
95 info.align_mask = do_colour_align ? (PAGE_MASK & shm_align_mask) : 0;
96 info.align_offset = pgoff << PAGE_SHIFT;
97 return vm_unmapped_area(info: &info);
98}
99
100unsigned long
101arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0,
102 const unsigned long len, const unsigned long pgoff,
103 const unsigned long flags, vm_flags_t vm_flags)
104{
105 struct vm_area_struct *vma;
106 struct mm_struct *mm = current->mm;
107 unsigned long addr = addr0;
108 int do_colour_align;
109 struct vm_unmapped_area_info info = {};
110
111 if (flags & MAP_FIXED) {
112 /* We do not accept a shared mapping if it would violate
113 * cache aliasing constraints.
114 */
115 if ((flags & MAP_SHARED) &&
116 ((addr - (pgoff << PAGE_SHIFT)) & shm_align_mask))
117 return -EINVAL;
118 return addr;
119 }
120
121 if (unlikely(len > TASK_SIZE))
122 return -ENOMEM;
123
124 do_colour_align = 0;
125 if (filp || (flags & MAP_SHARED))
126 do_colour_align = 1;
127
128 /* requesting a specific address */
129 if (addr) {
130 if (do_colour_align)
131 addr = COLOUR_ALIGN(addr, pgoff);
132 else
133 addr = PAGE_ALIGN(addr);
134
135 vma = find_vma(mm, addr);
136 if (TASK_SIZE - len >= addr &&
137 (!vma || addr + len <= vm_start_gap(vma)))
138 return addr;
139 }
140
141 info.flags = VM_UNMAPPED_AREA_TOPDOWN;
142 info.length = len;
143 info.low_limit = PAGE_SIZE;
144 info.high_limit = mm->mmap_base;
145 info.align_mask = do_colour_align ? (PAGE_MASK & shm_align_mask) : 0;
146 info.align_offset = pgoff << PAGE_SHIFT;
147 addr = vm_unmapped_area(info: &info);
148
149 /*
150 * A failed mmap() very likely causes application failure,
151 * so fall back to the bottom-up function here. This scenario
152 * can happen with large stack limits and large mmap()
153 * allocations.
154 */
155 if (addr & ~PAGE_MASK) {
156 VM_BUG_ON(addr != -ENOMEM);
157 info.flags = 0;
158 info.low_limit = TASK_UNMAPPED_BASE;
159 info.high_limit = TASK_SIZE;
160 addr = vm_unmapped_area(info: &info);
161 }
162
163 return addr;
164}
165#endif /* CONFIG_MMU */
166
167/*
168 * You really shouldn't be using read() or write() on /dev/mem. This
169 * might go away in the future.
170 */
171int valid_phys_addr_range(phys_addr_t addr, size_t count)
172{
173 if (addr < __MEMORY_START)
174 return 0;
175 if (addr + count > __pa(high_memory))
176 return 0;
177
178 return 1;
179}
180
181int valid_mmap_phys_addr_range(unsigned long pfn, size_t size)
182{
183 return 1;
184}
185

source code of linux/arch/sh/mm/mmap.c