blob: 2b7996401b0f9f602dfa2d809f86e40b57f79117 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * linux/arch/arm/mm/mmap.c
3 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07004#include <linux/fs.h>
5#include <linux/mm.h>
6#include <linux/mman.h>
7#include <linux/shm.h>
Alexey Dobriyane8edc6e2007-05-21 01:22:52 +04008#include <linux/sched.h>
Russell King09d9bae2008-09-05 14:08:44 +01009#include <linux/io.h>
Russell King0ba8b9b2008-08-10 18:08:10 +010010#include <asm/cputype.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070011#include <asm/system.h>
12
13#define COLOUR_ALIGN(addr,pgoff) \
14 ((((addr)+SHMLBA-1)&~(SHMLBA-1)) + \
15 (((pgoff)<<PAGE_SHIFT) & (SHMLBA-1)))
16
17/*
18 * We need to ensure that shared mappings are correctly aligned to
19 * avoid aliasing issues with VIPT caches. We need to ensure that
20 * a specific page of an object is always mapped at a multiple of
21 * SHMLBA bytes.
22 *
23 * We unconditionally provide this function for all cases, however
24 * in the VIVT case, we optimise out the alignment rules.
25 */
26unsigned long
27arch_get_unmapped_area(struct file *filp, unsigned long addr,
28 unsigned long len, unsigned long pgoff, unsigned long flags)
29{
30 struct mm_struct *mm = current->mm;
31 struct vm_area_struct *vma;
32 unsigned long start_addr;
33#ifdef CONFIG_CPU_V6
34 unsigned int cache_type;
35 int do_align = 0, aliasing = 0;
36
37 /*
38 * We only need to do colour alignment if either the I or D
39 * caches alias. This is indicated by bits 9 and 21 of the
40 * cache type register.
41 */
Russell King0ba8b9b2008-08-10 18:08:10 +010042 cache_type = read_cpuid_cachetype();
43 if (cache_type != read_cpuid_id()) {
Linus Torvalds1da177e2005-04-16 15:20:36 -070044 aliasing = (cache_type | cache_type >> 12) & (1 << 11);
45 if (aliasing)
46 do_align = filp || flags & MAP_SHARED;
47 }
48#else
49#define do_align 0
50#define aliasing 0
51#endif
52
53 /*
Benjamin Herrenschmidtacec0ac2007-05-06 14:50:07 -070054 * We enforce the MAP_FIXED case.
Linus Torvalds1da177e2005-04-16 15:20:36 -070055 */
56 if (flags & MAP_FIXED) {
57 if (aliasing && flags & MAP_SHARED && addr & (SHMLBA - 1))
58 return -EINVAL;
59 return addr;
60 }
61
62 if (len > TASK_SIZE)
63 return -ENOMEM;
64
65 if (addr) {
66 if (do_align)
67 addr = COLOUR_ALIGN(addr, pgoff);
68 else
69 addr = PAGE_ALIGN(addr);
70
71 vma = find_vma(mm, addr);
72 if (TASK_SIZE - len >= addr &&
73 (!vma || addr + len <= vma->vm_start))
74 return addr;
75 }
Wolfgang Wander1363c3c2005-06-21 17:14:49 -070076 if (len > mm->cached_hole_size) {
77 start_addr = addr = mm->free_area_cache;
78 } else {
79 start_addr = addr = TASK_UNMAPPED_BASE;
80 mm->cached_hole_size = 0;
81 }
Linus Torvalds1da177e2005-04-16 15:20:36 -070082
83full_search:
84 if (do_align)
85 addr = COLOUR_ALIGN(addr, pgoff);
86 else
87 addr = PAGE_ALIGN(addr);
88
89 for (vma = find_vma(mm, addr); ; vma = vma->vm_next) {
90 /* At this point: (!vma || addr < vma->vm_end). */
91 if (TASK_SIZE - len < addr) {
92 /*
93 * Start a new search - just in case we missed
94 * some holes.
95 */
96 if (start_addr != TASK_UNMAPPED_BASE) {
97 start_addr = addr = TASK_UNMAPPED_BASE;
Wolfgang Wander1363c3c2005-06-21 17:14:49 -070098 mm->cached_hole_size = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -070099 goto full_search;
100 }
101 return -ENOMEM;
102 }
103 if (!vma || addr + len <= vma->vm_start) {
104 /*
105 * Remember the place where we stopped the search:
106 */
107 mm->free_area_cache = addr + len;
108 return addr;
109 }
Wolfgang Wander1363c3c2005-06-21 17:14:49 -0700110 if (addr + mm->cached_hole_size < vma->vm_start)
111 mm->cached_hole_size = vma->vm_start - addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700112 addr = vma->vm_end;
113 if (do_align)
114 addr = COLOUR_ALIGN(addr, pgoff);
115 }
116}
117
Lennert Buytenhek51635ad2006-09-16 10:50:22 +0100118
119/*
120 * You really shouldn't be using read() or write() on /dev/mem. This
121 * might go away in the future.
122 */
123int valid_phys_addr_range(unsigned long addr, size_t size)
124{
Alexandre Rusev9ae3ae02008-02-26 18:42:10 +0100125 if (addr < PHYS_OFFSET)
126 return 0;
Greg Ungerer6806bfe2009-10-02 00:45:28 +0100127 if (addr + size > __pa(high_memory - 1) + 1)
Lennert Buytenhek51635ad2006-09-16 10:50:22 +0100128 return 0;
129
130 return 1;
131}
132
133/*
134 * We don't use supersection mappings for mmap() on /dev/mem, which
135 * means that we can't map the memory area above the 4G barrier into
136 * userspace.
137 */
138int valid_mmap_phys_addr_range(unsigned long pfn, size_t size)
139{
140 return !(pfn + (size >> PAGE_SHIFT) > 0x00100000);
141}