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 */
30unsigned long
31arch_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 <= vma->vm_start))
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