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
20 struct page_change_data {
21 pgprot_t set_mask;
22 pgprot_t clear_mask;
23 };
24
change_page_range(pte_t * ptep,pgtable_t token,unsigned long addr,void * data)25 static 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
in_range(unsigned long start,unsigned long size,unsigned long range_start,unsigned long range_end)38 static 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
change_memory_common(unsigned long addr,int numpages,pgprot_t set_mask,pgprot_t clear_mask)45 static 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
set_memory_ro(unsigned long addr,int numpages)73 int 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
set_memory_rw(unsigned long addr,int numpages)80 int 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
set_memory_nx(unsigned long addr,int numpages)87 int 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
set_memory_x(unsigned long addr,int numpages)94 int 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 }
100
