1 /*
2 * ARC700 mmap
3 *
4 * (started from arm version - for VIPT alias handling)
5 *
6 * Copyright (C) 2013 Synopsys, Inc. (www.synopsys.com)
7 *
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License version 2 as
10 * published by the Free Software Foundation.
11 */
12
13 #include <linux/fs.h>
14 #include <linux/mm.h>
15 #include <linux/mman.h>
16 #include <linux/sched.h>
17 #include <asm/cacheflush.h>
18
19 #define COLOUR_ALIGN(addr, pgoff) \
20 ((((addr) + SHMLBA - 1) & ~(SHMLBA - 1)) + \
21 (((pgoff) << PAGE_SHIFT) & (SHMLBA - 1)))
22
23 /*
24 * Ensure that shared mappings are correctly aligned to
25 * avoid aliasing issues with VIPT caches.
26 * We need to ensure that
27 * a specific page of an object is always mapped at a multiple of
28 * SHMLBA bytes.
29 */
30 unsigned long
arch_get_unmapped_area(struct file * filp,unsigned long addr,unsigned long len,unsigned long pgoff,unsigned long flags)31 arch_get_unmapped_area(struct file *filp, unsigned long addr,
32 unsigned long len, unsigned long pgoff, unsigned long flags)
33 {
34 struct mm_struct *mm = current->mm;
35 struct vm_area_struct *vma;
36 int do_align = 0;
37 int aliasing = cache_is_vipt_aliasing();
38 struct vm_unmapped_area_info info;
39
40 /*
41 * We only need to do colour alignment if D cache aliases.
42 */
43 if (aliasing)
44 do_align = filp || (flags & MAP_SHARED);
45
46 /*
47 * We enforce the MAP_FIXED case.
48 */
49 if (flags & MAP_FIXED) {
50 if (aliasing && flags & MAP_SHARED &&
51 (addr - (pgoff << PAGE_SHIFT)) & (SHMLBA - 1))
52 return -EINVAL;
53 return addr;
54 }
55
56 if (len > TASK_SIZE)
57 return -ENOMEM;
58
59 if (addr) {
60 if (do_align)
61 addr = COLOUR_ALIGN(addr, pgoff);
62 else
63 addr = PAGE_ALIGN(addr);
64
65 vma = find_vma(mm, addr);
66 if (TASK_SIZE - len >= addr &&
67 (!vma || addr + len <= vm_start_gap(vma)))
68 return addr;
69 }
70
71 info.flags = 0;
72 info.length = len;
73 info.low_limit = mm->mmap_base;
74 info.high_limit = TASK_SIZE;
75 info.align_mask = do_align ? (PAGE_MASK & (SHMLBA - 1)) : 0;
76 info.align_offset = pgoff << PAGE_SHIFT;
77 return vm_unmapped_area(&info);
78 }
79