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
change_page_attr(unsigned long addr,int numpages,pte_t (* set)(pte_t))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
set_memory_ro(unsigned long addr,int numpages)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
set_memory_rw(unsigned long addr,int numpages)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 */
set_memory_nx(unsigned long addr,int numpages)53 int set_memory_nx(unsigned long addr, int numpages)
54 {
55 return 0;
56 }
57 EXPORT_SYMBOL_GPL(set_memory_nx);
58
set_memory_x(unsigned long addr,int numpages)59 int set_memory_x(unsigned long addr, int numpages)
60 {
61 return 0;
62 }
63