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 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 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 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 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 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 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 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