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/cacheflush.h>
   9 #include <asm/pgtable.h>
  10
  11 static void change_page_attr(unsigned long addr, int numpages,
  12                              pte_t (*set) (pte_t))
  13 {
  14         pte_t *ptep, pte;
  15         pmd_t *pmdp;
  16         pud_t *pudp;
  17         pgd_t *pgdp;
  18         int i;
  19
  20         for (i = 0; i < numpages; i++) {
  21                 pgdp = pgd_offset(&init_mm, addr);
  22                 pudp = pud_offset(pgdp, addr);
  23                 pmdp = pmd_offset(pudp, addr);
  24                 if (pmd_huge(*pmdp)) {
  25                         WARN_ON_ONCE(1);
  26                         continue;
  27                 }
  28                 ptep = pte_offset_kernel(pmdp, addr);
  29
  30                 pte = *ptep;
  31                 pte = set(pte);
  32                 __ptep_ipte(addr, ptep);
  33                 *ptep = pte;
  34                 addr += PAGE_SIZE;
  35         }
  36 }
  37
  38 int set_memory_ro(unsigned long addr, int numpages)
  39 {
  40         change_page_attr(addr, numpages, pte_wrprotect);
  41         return 0;
  42 }
  43 EXPORT_SYMBOL_GPL(set_memory_ro);
  44
  45 int set_memory_rw(unsigned long addr, int numpages)
  46 {
  47         change_page_attr(addr, numpages, pte_mkwrite);
  48         return 0;
  49 }
  50 EXPORT_SYMBOL_GPL(set_memory_rw);
  51
  52 /* not possible */
  53 int set_memory_nx(unsigned long addr, int numpages)
  54 {
  55         return 0;
  56 }
  57 EXPORT_SYMBOL_GPL(set_memory_nx);
  58
  59 int set_memory_x(unsigned long addr, int numpages)
  60 {
  61         return 0;
  62 }