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/mm.h>
17
18#include <asm/cacheflush.h>
19
20#define COLOUR_ALIGN(addr, pgoff)			\
21	((((addr) + SHMLBA - 1) & ~(SHMLBA - 1)) +	\
22	 (((pgoff) << PAGE_SHIFT) & (SHMLBA - 1)))
23
24/*
25 * Ensure that shared mappings are correctly aligned to
26 * avoid aliasing issues with VIPT caches.
27 * We need to ensure that
28 * a specific page of an object is always mapped at a multiple of
29 * SHMLBA bytes.
30 */
31unsigned long
32arch_get_unmapped_area(struct file *filp, unsigned long addr,
33		unsigned long len, unsigned long pgoff, unsigned long flags)
34{
35	struct mm_struct *mm = current->mm;
36	struct vm_area_struct *vma;
37	int do_align = 0;
38	int aliasing = cache_is_vipt_aliasing();
39	struct vm_unmapped_area_info info;
40
41	/*
42	 * We only need to do colour alignment if D cache aliases.
43	 */
44	if (aliasing)
45		do_align = filp || (flags & MAP_SHARED);
46
47	/*
48	 * We enforce the MAP_FIXED case.
49	 */
50	if (flags & MAP_FIXED) {
51		if (aliasing && flags & MAP_SHARED &&
52		    (addr - (pgoff << PAGE_SHIFT)) & (SHMLBA - 1))
53			return -EINVAL;
54		return addr;
55	}
56
57	if (len > TASK_SIZE)
58		return -ENOMEM;
59
60	if (addr) {
61		if (do_align)
62			addr = COLOUR_ALIGN(addr, pgoff);
63		else
64			addr = PAGE_ALIGN(addr);
65
66		vma = find_vma(mm, addr);
67		if (TASK_SIZE - len >= addr &&
68		    (!vma || addr + len <= vm_start_gap(vma)))
69			return addr;
70	}
71
72	info.flags = 0;
73	info.length = len;
74	info.low_limit = mm->mmap_base;
75	info.high_limit = TASK_SIZE;
76	info.align_mask = do_align ? (PAGE_MASK & (SHMLBA - 1)) : 0;
77	info.align_offset = pgoff << PAGE_SHIFT;
78	return vm_unmapped_area(&info);
79}