LXR linux/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
  21struct page_change_data {
  22        pgprot_t set_mask;
  23        pgprot_t clear_mask;
  24};
  25
  26static 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
  39static 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 (!is_module_address(start) || !is_module_address(end - 1))
  55                return -EINVAL;
  56
  57        data.set_mask = set_mask;
  58        data.clear_mask = clear_mask;
  59
  60        ret = apply_to_page_range(&init_mm, start, size, change_page_range,
  61                                        &data);
  62
  63        flush_tlb_kernel_range(start, end);
  64        return ret;
  65}
  66
  67int set_memory_ro(unsigned long addr, int numpages)
  68{
  69        return change_memory_common(addr, numpages,
  70                                        __pgprot(PTE_RDONLY),
  71                                        __pgprot(PTE_WRITE));
  72}
  73EXPORT_SYMBOL_GPL(set_memory_ro);
  74
  75int set_memory_rw(unsigned long addr, int numpages)
  76{
  77        return change_memory_common(addr, numpages,
  78                                        __pgprot(PTE_WRITE),
  79                                        __pgprot(PTE_RDONLY));
  80}
  81EXPORT_SYMBOL_GPL(set_memory_rw);
  82
  83int set_memory_nx(unsigned long addr, int numpages)
  84{
  85        return change_memory_common(addr, numpages,
  86                                        __pgprot(PTE_PXN),
  87                                        __pgprot(0));
  88}
  89EXPORT_SYMBOL_GPL(set_memory_nx);
  90
  91int set_memory_x(unsigned long addr, int numpages)
  92{
  93        return change_memory_common(addr, numpages,
  94                                        __pgprot(0),
  95                                        __pgprot(PTE_PXN));
  96}
  97EXPORT_SYMBOL_GPL(set_memory_x);
  98