arch/s390/mm/pageattr.c

   1 /*
   2  * Copyright IBM Corp. 2011
   3  * Author(s): Jan Glauber <jang@linux.vnet.ibm.com>
   4  */
   5 #include <linux/module.h>
   6 #include <linux/mm.h>
   7 #include <linux/hugetlb.h>
   8 #include <asm/pgtable.h>
   9
  10 static void change_page_attr(unsigned long addr, int numpages,
  11                              pte_t (*set) (pte_t))
  12 {
  13         pte_t *ptep, pte;
  14         pmd_t *pmdp;
  15         pud_t *pudp;
  16         pgd_t *pgdp;
  17         int i;
  18
  19         for (i = 0; i < numpages; i++) {
  20                 pgdp = pgd_offset(&init_mm, addr);
  21                 pudp = pud_offset(pgdp, addr);
  22                 pmdp = pmd_offset(pudp, addr);
  23                 if (pmd_huge(*pmdp)) {
  24                         WARN_ON_ONCE(1);
  25                         continue;
  26                 }
  27                 ptep = pte_offset_kernel(pmdp, addr);
  28
  29                 pte = *ptep;
  30                 pte = set(pte);
  31                 __ptep_ipte(addr, ptep);
  32                 *ptep = pte;
  33                 addr += PAGE_SIZE;
  34         }
  35 }
  36
  37 int set_memory_ro(unsigned long addr, int numpages)
  38 {
  39         change_page_attr(addr, numpages, pte_wrprotect);
  40         return 0;
  41 }
  42 EXPORT_SYMBOL_GPL(set_memory_ro);
  43
  44 int set_memory_rw(unsigned long addr, int numpages)
  45 {
  46         change_page_attr(addr, numpages, pte_mkwrite);
  47         return 0;
  48 }
  49 EXPORT_SYMBOL_GPL(set_memory_rw);
  50
  51 /* not possible */
  52 int set_memory_nx(unsigned long addr, int numpages)
  53 {
  54         return 0;
  55 }
  56 EXPORT_SYMBOL_GPL(set_memory_nx);
  57
  58 int set_memory_x(unsigned long addr, int numpages)
  59 {
  60         return 0;
  61 }