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 + i * PAGE_SIZE);
  28
  29                 pte = *ptep;
  30                 pte = set(pte);
  31                 ptep_invalidate(&init_mm, addr + i * PAGE_SIZE, ptep);
  32                 *ptep = pte;
  33         }
  34 }
  35
  36 int set_memory_ro(unsigned long addr, int numpages)
  37 {
  38         change_page_attr(addr, numpages, pte_wrprotect);
  39         return 0;
  40 }
  41 EXPORT_SYMBOL_GPL(set_memory_ro);
  42
  43 int set_memory_rw(unsigned long addr, int numpages)
  44 {
  45         change_page_attr(addr, numpages, pte_mkwrite);
  46         return 0;
  47 }
  48 EXPORT_SYMBOL_GPL(set_memory_rw);
  49
  50 /* not possible */
  51 int set_memory_nx(unsigned long addr, int numpages)
  52 {
  53         return 0;
  54 }
  55 EXPORT_SYMBOL_GPL(set_memory_nx);