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/mman.h>
13#include <linux/module.h>
14#include <asm/page.h>
15#include <asm/processor.h>
16
17unsigned long shm_align_mask = PAGE_SIZE - 1;	/* Sane caches */
18EXPORT_SYMBOL(shm_align_mask);
19
20#ifdef CONFIG_MMU
21/*
22 * To avoid cache aliases, we map the shared page with same color.
23 */
24static inline unsigned long COLOUR_ALIGN(unsigned long addr,
25					 unsigned long pgoff)
26{
27	unsigned long base = (addr + shm_align_mask) & ~shm_align_mask;
28	unsigned long off = (pgoff << PAGE_SHIFT) & shm_align_mask;
29
30	return base + off;
31}
32
33unsigned long arch_get_unmapped_area(struct file *filp, unsigned long addr,
34	unsigned long len, unsigned long pgoff, unsigned long flags)
35{
36	struct mm_struct *mm = current->mm;
37	struct vm_area_struct *vma;
38	int do_colour_align;
39	struct vm_unmapped_area_info info;
40
41	if (flags & MAP_FIXED) {
42		/* We do not accept a shared mapping if it would violate
43		 * cache aliasing constraints.
44		 */
45		if ((flags & MAP_SHARED) &&
46		    ((addr - (pgoff << PAGE_SHIFT)) & shm_align_mask))
47			return -EINVAL;
48		return addr;
49	}
50
51	if (unlikely(len > TASK_SIZE))
52		return -ENOMEM;
53
54	do_colour_align = 0;
55	if (filp || (flags & MAP_SHARED))
56		do_colour_align = 1;
57
58	if (addr) {
59		if (do_colour_align)
60			addr = COLOUR_ALIGN(addr, pgoff);
61		else
62			addr = PAGE_ALIGN(addr);
63
64		vma = find_vma(mm, addr);
65		if (TASK_SIZE - len >= addr &&
66		    (!vma || addr + len <= vma->vm_start))
67			return addr;
68	}
69
70	info.flags = 0;
71	info.length = len;
72	info.low_limit = TASK_UNMAPPED_BASE;
73	info.high_limit = TASK_SIZE;
74	info.align_mask = do_colour_align ? (PAGE_MASK & shm_align_mask) : 0;
75	info.align_offset = pgoff << PAGE_SHIFT;
76	return vm_unmapped_area(&info);
77}
78
79unsigned long
80arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0,
81			  const unsigned long len, const unsigned long pgoff,
82			  const unsigned long flags)
83{
84	struct vm_area_struct *vma;
85	struct mm_struct *mm = current->mm;
86	unsigned long addr = addr0;
87	int do_colour_align;
88	struct vm_unmapped_area_info info;
89
90	if (flags & MAP_FIXED) {
91		/* We do not accept a shared mapping if it would violate
92		 * cache aliasing constraints.
93		 */
94		if ((flags & MAP_SHARED) &&
95		    ((addr - (pgoff << PAGE_SHIFT)) & shm_align_mask))
96			return -EINVAL;
97		return addr;
98	}
99
100	if (unlikely(len > TASK_SIZE))
101		return -ENOMEM;
102
103	do_colour_align = 0;
104	if (filp || (flags & MAP_SHARED))
105		do_colour_align = 1;
106
107	/* requesting a specific address */
108	if (addr) {
109		if (do_colour_align)
110			addr = COLOUR_ALIGN(addr, pgoff);
111		else
112			addr = PAGE_ALIGN(addr);
113
114		vma = find_vma(mm, addr);
115		if (TASK_SIZE - len >= addr &&
116		    (!vma || addr + len <= vma->vm_start))
117			return addr;
118	}
119
120	info.flags = VM_UNMAPPED_AREA_TOPDOWN;
121	info.length = len;
122	info.low_limit = PAGE_SIZE;
123	info.high_limit = mm->mmap_base;
124	info.align_mask = do_colour_align ? (PAGE_MASK & shm_align_mask) : 0;
125	info.align_offset = pgoff << PAGE_SHIFT;
126	addr = vm_unmapped_area(&info);
127
128	/*
129	 * A failed mmap() very likely causes application failure,
130	 * so fall back to the bottom-up function here. This scenario
131	 * can happen with large stack limits and large mmap()
132	 * allocations.
133	 */
134	if (addr & ~PAGE_MASK) {
135		VM_BUG_ON(addr != -ENOMEM);
136		info.flags = 0;
137		info.low_limit = TASK_UNMAPPED_BASE;
138		info.high_limit = TASK_SIZE;
139		addr = vm_unmapped_area(&info);
140	}
141
142	return addr;
143}
144#endif /* CONFIG_MMU */
145
146/*
147 * You really shouldn't be using read() or write() on /dev/mem.  This
148 * might go away in the future.
149 */
150int valid_phys_addr_range(phys_addr_t addr, size_t count)
151{
152	if (addr < __MEMORY_START)
153		return 0;
154	if (addr + count > __pa(high_memory))
155		return 0;
156
157	return 1;
158}
159
160int valid_mmap_phys_addr_range(unsigned long pfn, size_t size)
161{
162	return 1;
163}
164