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  */
COLOUR_ALIGN(unsigned long addr,unsigned long pgoff)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 
arch_get_unmapped_area(struct file * filp,unsigned long addr,unsigned long len,unsigned long pgoff,unsigned long flags)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.flags = 0;
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);
98 }
99 
100 unsigned long
arch_get_unmapped_area_topdown(struct file * filp,const unsigned long addr0,const unsigned long len,const unsigned long pgoff,const unsigned long flags)101 arch_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)
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);
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);
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  */
valid_phys_addr_range(phys_addr_t addr,size_t count)171 int 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 
valid_mmap_phys_addr_range(unsigned long pfn,size_t size)181 int valid_mmap_phys_addr_range(unsigned long pfn, size_t size)
182 {
183 	return 1;
184 }
185