1/*
 2 * Copyright (c) 2014, The Linux Foundation. All rights reserved.
 3 *
 4 * This program is free software; you can redistribute it and/or modify
 5 * it under the terms of the GNU General Public License version 2 and
 6 * only version 2 as published by the Free Software Foundation.
 7 *
 8 * This program is distributed in the hope that it will be useful,
 9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
11 * GNU General Public License for more details.
12 */
13#include <linux/mm.h>
14#include <linux/module.h>
15
16#include <asm/pgtable.h>
17#include <asm/tlbflush.h>
18#include <asm/set_memory.h>
19
20struct page_change_data {
21	pgprot_t set_mask;
22	pgprot_t clear_mask;
23};
24
25static int change_page_range(pte_t *ptep, pgtable_t token, unsigned long addr,
26			void *data)
27{
28	struct page_change_data *cdata = data;
29	pte_t pte = *ptep;
30
31	pte = clear_pte_bit(pte, cdata->clear_mask);
32	pte = set_pte_bit(pte, cdata->set_mask);
33
34	set_pte_ext(ptep, pte, 0);
35	return 0;
36}
37
38static bool in_range(unsigned long start, unsigned long size,
39	unsigned long range_start, unsigned long range_end)
40{
41	return start >= range_start && start < range_end &&
42		size <= range_end - start;
43}
44
45static int change_memory_common(unsigned long addr, int numpages,
46				pgprot_t set_mask, pgprot_t clear_mask)
47{
48	unsigned long start = addr & PAGE_MASK;
49	unsigned long end = PAGE_ALIGN(addr) + numpages * PAGE_SIZE;
50	unsigned long size = end - start;
51	int ret;
52	struct page_change_data data;
53
54	WARN_ON_ONCE(start != addr);
55
56	if (!size)
57		return 0;
58
59	if (!in_range(start, size, MODULES_VADDR, MODULES_END) &&
60	    !in_range(start, size, VMALLOC_START, VMALLOC_END))
61		return -EINVAL;
62
63	data.set_mask = set_mask;
64	data.clear_mask = clear_mask;
65
66	ret = apply_to_page_range(&init_mm, start, size, change_page_range,
67					&data);
68
69	flush_tlb_kernel_range(start, end);
70	return ret;
71}
72
73int set_memory_ro(unsigned long addr, int numpages)
74{
75	return change_memory_common(addr, numpages,
76					__pgprot(L_PTE_RDONLY),
77					__pgprot(0));
78}
79
80int set_memory_rw(unsigned long addr, int numpages)
81{
82	return change_memory_common(addr, numpages,
83					__pgprot(0),
84					__pgprot(L_PTE_RDONLY));
85}
86
87int set_memory_nx(unsigned long addr, int numpages)
88{
89	return change_memory_common(addr, numpages,
90					__pgprot(L_PTE_XN),
91					__pgprot(0));
92}
93
94int set_memory_x(unsigned long addr, int numpages)
95{
96	return change_memory_common(addr, numpages,
97					__pgprot(0),
98					__pgprot(L_PTE_XN));
99}