arch/arm64/mm/pageattr.c

   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                 start &= PAGE_MASK;
  50                 end = start + size;
  51                 WARN_ON_ONCE(1);
  52         }
  53
  54         if (start < MODULES_VADDR || start >= MODULES_END)
  55                 return -EINVAL;
  56
  57         if (end < MODULES_VADDR || end >= MODULES_END)
  58                 return -EINVAL;
  59
  60         data.set_mask = set_mask;
  61         data.clear_mask = clear_mask;
  62
  63         ret = apply_to_page_range(&init_mm, start, size, change_page_range,
  64                                         &data);
  65
  66         flush_tlb_kernel_range(start, end);
  67         return ret;
  68 }
  69
  70 int set_memory_ro(unsigned long addr, int numpages)
  71 {
  72         return change_memory_common(addr, numpages,
  73                                         __pgprot(PTE_RDONLY),
  74                                         __pgprot(PTE_WRITE));
  75 }
  76
  77 int set_memory_rw(unsigned long addr, int numpages)
  78 {
  79         return change_memory_common(addr, numpages,
  80                                         __pgprot(PTE_WRITE),
  81                                         __pgprot(PTE_RDONLY));
  82 }
  83
  84 int set_memory_nx(unsigned long addr, int numpages)
  85 {
  86         return change_memory_common(addr, numpages,
  87                                         __pgprot(PTE_PXN),
  88                                         __pgprot(0));
  89 }
  90 EXPORT_SYMBOL_GPL(set_memory_nx);
  91
  92 int set_memory_x(unsigned long addr, int numpages)
  93 {
  94         return change_memory_common(addr, numpages,
  95                                         __pgprot(0),
  96                                         __pgprot(PTE_PXN));
  97 }
  98 EXPORT_SYMBOL_GPL(set_memory_x);