1*4882a593Smuzhiyun // SPDX-License-Identifier: GPL-2.0-only
2*4882a593Smuzhiyun /*
3*4882a593Smuzhiyun * ARC700 mmap
4*4882a593Smuzhiyun *
5*4882a593Smuzhiyun * (started from arm version - for VIPT alias handling)
6*4882a593Smuzhiyun *
7*4882a593Smuzhiyun * Copyright (C) 2013 Synopsys, Inc. (www.synopsys.com)
8*4882a593Smuzhiyun */
9*4882a593Smuzhiyun
10*4882a593Smuzhiyun #include <linux/fs.h>
11*4882a593Smuzhiyun #include <linux/mm.h>
12*4882a593Smuzhiyun #include <linux/mman.h>
13*4882a593Smuzhiyun #include <linux/sched/mm.h>
14*4882a593Smuzhiyun
15*4882a593Smuzhiyun #include <asm/cacheflush.h>
16*4882a593Smuzhiyun
17*4882a593Smuzhiyun #define COLOUR_ALIGN(addr, pgoff) \
18*4882a593Smuzhiyun ((((addr) + SHMLBA - 1) & ~(SHMLBA - 1)) + \
19*4882a593Smuzhiyun (((pgoff) << PAGE_SHIFT) & (SHMLBA - 1)))
20*4882a593Smuzhiyun
21*4882a593Smuzhiyun /*
22*4882a593Smuzhiyun * Ensure that shared mappings are correctly aligned to
23*4882a593Smuzhiyun * avoid aliasing issues with VIPT caches.
24*4882a593Smuzhiyun * We need to ensure that
25*4882a593Smuzhiyun * a specific page of an object is always mapped at a multiple of
26*4882a593Smuzhiyun * SHMLBA bytes.
27*4882a593Smuzhiyun */
28*4882a593Smuzhiyun unsigned long
arch_get_unmapped_area(struct file * filp,unsigned long addr,unsigned long len,unsigned long pgoff,unsigned long flags)29*4882a593Smuzhiyun arch_get_unmapped_area(struct file *filp, unsigned long addr,
30*4882a593Smuzhiyun unsigned long len, unsigned long pgoff, unsigned long flags)
31*4882a593Smuzhiyun {
32*4882a593Smuzhiyun struct mm_struct *mm = current->mm;
33*4882a593Smuzhiyun struct vm_area_struct *vma;
34*4882a593Smuzhiyun int do_align = 0;
35*4882a593Smuzhiyun int aliasing = cache_is_vipt_aliasing();
36*4882a593Smuzhiyun struct vm_unmapped_area_info info;
37*4882a593Smuzhiyun
38*4882a593Smuzhiyun /*
39*4882a593Smuzhiyun * We only need to do colour alignment if D cache aliases.
40*4882a593Smuzhiyun */
41*4882a593Smuzhiyun if (aliasing)
42*4882a593Smuzhiyun do_align = filp || (flags & MAP_SHARED);
43*4882a593Smuzhiyun
44*4882a593Smuzhiyun /*
45*4882a593Smuzhiyun * We enforce the MAP_FIXED case.
46*4882a593Smuzhiyun */
47*4882a593Smuzhiyun if (flags & MAP_FIXED) {
48*4882a593Smuzhiyun if (aliasing && flags & MAP_SHARED &&
49*4882a593Smuzhiyun (addr - (pgoff << PAGE_SHIFT)) & (SHMLBA - 1))
50*4882a593Smuzhiyun return -EINVAL;
51*4882a593Smuzhiyun return addr;
52*4882a593Smuzhiyun }
53*4882a593Smuzhiyun
54*4882a593Smuzhiyun if (len > TASK_SIZE)
55*4882a593Smuzhiyun return -ENOMEM;
56*4882a593Smuzhiyun
57*4882a593Smuzhiyun if (addr) {
58*4882a593Smuzhiyun if (do_align)
59*4882a593Smuzhiyun addr = COLOUR_ALIGN(addr, pgoff);
60*4882a593Smuzhiyun else
61*4882a593Smuzhiyun addr = PAGE_ALIGN(addr);
62*4882a593Smuzhiyun
63*4882a593Smuzhiyun vma = find_vma(mm, addr);
64*4882a593Smuzhiyun if (TASK_SIZE - len >= addr &&
65*4882a593Smuzhiyun (!vma || addr + len <= vm_start_gap(vma)))
66*4882a593Smuzhiyun return addr;
67*4882a593Smuzhiyun }
68*4882a593Smuzhiyun
69*4882a593Smuzhiyun info.flags = 0;
70*4882a593Smuzhiyun info.length = len;
71*4882a593Smuzhiyun info.low_limit = mm->mmap_base;
72*4882a593Smuzhiyun info.high_limit = TASK_SIZE;
73*4882a593Smuzhiyun info.align_mask = do_align ? (PAGE_MASK & (SHMLBA - 1)) : 0;
74*4882a593Smuzhiyun info.align_offset = pgoff << PAGE_SHIFT;
75*4882a593Smuzhiyun return vm_unmapped_area(&info);
76*4882a593Smuzhiyun }
77