xref: /linux/arch/arc/mm/mmap.c (revision 3ea5eb68b9d624935108b5e696859304edfac202)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * ARC700 mmap
4  *
5  * (started from arm version - for VIPT alias handling)
6  *
7  * Copyright (C) 2013 Synopsys, Inc. (www.synopsys.com)
8  */
9 
10 #include <linux/fs.h>
11 #include <linux/mm.h>
12 #include <linux/mman.h>
13 #include <linux/sched/mm.h>
14 
15 #include <asm/cacheflush.h>
16 
17 /*
18  * Ensure that shared mappings are correctly aligned to
19  * avoid aliasing issues with VIPT caches.
20  * We need to ensure that
21  * a specific page of an object is always mapped at a multiple of
22  * SHMLBA bytes.
23  */
24 unsigned long
25 arch_get_unmapped_area(struct file *filp, unsigned long addr,
26 		unsigned long len, unsigned long pgoff,
27 		unsigned long flags, vm_flags_t vm_flags)
28 {
29 	struct mm_struct *mm = current->mm;
30 	struct vm_area_struct *vma;
31 	struct vm_unmapped_area_info info = {};
32 
33 	/*
34 	 * We enforce the MAP_FIXED case.
35 	 */
36 	if (flags & MAP_FIXED) {
37 		if (flags & MAP_SHARED &&
38 		    (addr - (pgoff << PAGE_SHIFT)) & (SHMLBA - 1))
39 			return -EINVAL;
40 		return addr;
41 	}
42 
43 	if (len > TASK_SIZE)
44 		return -ENOMEM;
45 
46 	if (addr) {
47 		addr = PAGE_ALIGN(addr);
48 
49 		vma = find_vma(mm, addr);
50 		if (TASK_SIZE - len >= addr &&
51 		    (!vma || addr + len <= vm_start_gap(vma)))
52 			return addr;
53 	}
54 
55 	info.length = len;
56 	info.low_limit = mm->mmap_base;
57 	info.high_limit = TASK_SIZE;
58 	info.align_offset = pgoff << PAGE_SHIFT;
59 	return vm_unmapped_area(&info);
60 }
61 
62 static const pgprot_t protection_map[16] = {
63 	[VM_NONE]					= PAGE_U_NONE,
64 	[VM_READ]					= PAGE_U_R,
65 	[VM_WRITE]					= PAGE_U_R,
66 	[VM_WRITE | VM_READ]				= PAGE_U_R,
67 	[VM_EXEC]					= PAGE_U_X_R,
68 	[VM_EXEC | VM_READ]				= PAGE_U_X_R,
69 	[VM_EXEC | VM_WRITE]				= PAGE_U_X_R,
70 	[VM_EXEC | VM_WRITE | VM_READ]			= PAGE_U_X_R,
71 	[VM_SHARED]					= PAGE_U_NONE,
72 	[VM_SHARED | VM_READ]				= PAGE_U_R,
73 	[VM_SHARED | VM_WRITE]				= PAGE_U_W_R,
74 	[VM_SHARED | VM_WRITE | VM_READ]		= PAGE_U_W_R,
75 	[VM_SHARED | VM_EXEC]				= PAGE_U_X_R,
76 	[VM_SHARED | VM_EXEC | VM_READ]			= PAGE_U_X_R,
77 	[VM_SHARED | VM_EXEC | VM_WRITE]		= PAGE_U_X_W_R,
78 	[VM_SHARED | VM_EXEC | VM_WRITE | VM_READ]	= PAGE_U_X_W_R
79 };
80 DECLARE_VM_GET_PAGE_PROT
81