| Laura Abbott | da81aae | 2014-08-19 20:41:43 +0100 | [diff] [blame] | 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/kernel.h> |
| 14 | #include <linux/mm.h> |
| 15 | #include <linux/module.h> |
| 16 | #include <linux/sched.h> |
| 17 | |
| 18 | #include <asm/pgtable.h> |
| 19 | #include <asm/tlbflush.h> |
| 20 | |
| 21 | struct page_change_data { |
| 22 | pgprot_t set_mask; |
| 23 | pgprot_t clear_mask; |
| 24 | }; |
| 25 | |
| 26 | static int change_page_range(pte_t *ptep, pgtable_t token, unsigned long addr, |
| 27 | void *data) |
| 28 | { |
| 29 | struct page_change_data *cdata = data; |
| 30 | pte_t pte = *ptep; |
| 31 | |
| 32 | pte = clear_pte_bit(pte, cdata->clear_mask); |
| 33 | pte = set_pte_bit(pte, cdata->set_mask); |
| 34 | |
| 35 | set_pte(ptep, pte); |
| 36 | return 0; |
| 37 | } |
| 38 | |
| 39 | static int change_memory_common(unsigned long addr, int numpages, |
| 40 | pgprot_t set_mask, pgprot_t clear_mask) |
| 41 | { |
| 42 | unsigned long start = addr; |
| 43 | unsigned long size = PAGE_SIZE*numpages; |
| 44 | unsigned long end = start + size; |
| 45 | int ret; |
| 46 | struct page_change_data data; |
| 47 | |
| 48 | if (!IS_ALIGNED(addr, PAGE_SIZE)) { |
| 49 | addr &= PAGE_MASK; |
| 50 | WARN_ON_ONCE(1); |
| 51 | } |
| 52 | |
| 53 | if (!is_module_address(start) || !is_module_address(end - 1)) |
| 54 | return -EINVAL; |
| 55 | |
| 56 | data.set_mask = set_mask; |
| 57 | data.clear_mask = clear_mask; |
| 58 | |
| 59 | ret = apply_to_page_range(&init_mm, start, size, change_page_range, |
| 60 | &data); |
| 61 | |
| 62 | flush_tlb_kernel_range(start, end); |
| 63 | return ret; |
| 64 | } |
| 65 | |
| 66 | int set_memory_ro(unsigned long addr, int numpages) |
| 67 | { |
| 68 | return change_memory_common(addr, numpages, |
| 69 | __pgprot(PTE_RDONLY), |
| 70 | __pgprot(PTE_WRITE)); |
| 71 | } |
| 72 | EXPORT_SYMBOL_GPL(set_memory_ro); |
| 73 | |
| 74 | int set_memory_rw(unsigned long addr, int numpages) |
| 75 | { |
| 76 | return change_memory_common(addr, numpages, |
| 77 | __pgprot(PTE_WRITE), |
| 78 | __pgprot(PTE_RDONLY)); |
| 79 | } |
| 80 | EXPORT_SYMBOL_GPL(set_memory_rw); |
| 81 | |
| 82 | int set_memory_nx(unsigned long addr, int numpages) |
| 83 | { |
| 84 | return change_memory_common(addr, numpages, |
| 85 | __pgprot(PTE_PXN), |
| 86 | __pgprot(0)); |
| 87 | } |
| 88 | EXPORT_SYMBOL_GPL(set_memory_nx); |
| 89 | |
| 90 | int set_memory_x(unsigned long addr, int numpages) |
| 91 | { |
| 92 | return change_memory_common(addr, numpages, |
| 93 | __pgprot(0), |
| 94 | __pgprot(PTE_PXN)); |
| 95 | } |
| 96 | EXPORT_SYMBOL_GPL(set_memory_x); |