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/hugetlb.h>
   6 #include <linux/module.h>
   7 #include <linux/mm.h>
   8 #include <asm/cacheflush.h>
   9 #include <asm/pgtable.h>
  10 #include <asm/page.h>
  11
  12 void storage_key_init_range(unsigned long start, unsigned long end)
  13 {
  14         unsigned long boundary, function, size;
  15
  16         while (start < end) {
  17                 if (MACHINE_HAS_EDAT2) {
  18                         /* set storage keys for a 2GB frame */
  19                         function = 0x22000 | PAGE_DEFAULT_KEY;
  20                         size = 1UL << 31;
  21                         boundary = (start + size) & ~(size - 1);
  22                         if (boundary <= end) {
  23                                 do {
  24                                         start = pfmf(function, start);
  25                                 } while (start < boundary);
  26                                 continue;
  27                         }
  28                 }
  29                 if (MACHINE_HAS_EDAT1) {
  30                         /* set storage keys for a 1MB frame */
  31                         function = 0x21000 | PAGE_DEFAULT_KEY;
  32                         size = 1UL << 20;
  33                         boundary = (start + size) & ~(size - 1);
  34                         if (boundary <= end) {
  35                                 do {
  36                                         start = pfmf(function, start);
  37                                 } while (start < boundary);
  38                                 continue;
  39                         }
  40                 }
  41                 page_set_storage_key(start, PAGE_DEFAULT_KEY, 0);
  42                 start += PAGE_SIZE;
  43         }
  44 }
  45
  46 static pte_t *walk_page_table(unsigned long addr)
  47 {
  48         pgd_t *pgdp;
  49         pud_t *pudp;
  50         pmd_t *pmdp;
  51         pte_t *ptep;
  52
  53         pgdp = pgd_offset_k(addr);
  54         if (pgd_none(*pgdp))
  55                 return NULL;
  56         pudp = pud_offset(pgdp, addr);
  57         if (pud_none(*pudp) || pud_large(*pudp))
  58                 return NULL;
  59         pmdp = pmd_offset(pudp, addr);
  60         if (pmd_none(*pmdp) || pmd_large(*pmdp))
  61                 return NULL;
  62         ptep = pte_offset_kernel(pmdp, addr);
  63         if (pte_none(*ptep))
  64                 return NULL;
  65         return ptep;
  66 }
  67
  68 static void change_page_attr(unsigned long addr, int numpages,
  69                              pte_t (*set) (pte_t))
  70 {
  71         pte_t *ptep, pte;
  72         int i;
  73
  74         for (i = 0; i < numpages; i++) {
  75                 ptep = walk_page_table(addr);
  76                 if (WARN_ON_ONCE(!ptep))
  77                         break;
  78                 pte = *ptep;
  79                 pte = set(pte);
  80                 __ptep_ipte(addr, ptep);
  81                 *ptep = pte;
  82                 addr += PAGE_SIZE;
  83         }
  84 }
  85
  86 int set_memory_ro(unsigned long addr, int numpages)
  87 {
  88         change_page_attr(addr, numpages, pte_wrprotect);
  89         return 0;
  90 }
  91
  92 int set_memory_rw(unsigned long addr, int numpages)
  93 {
  94         change_page_attr(addr, numpages, pte_mkwrite);
  95         return 0;
  96 }
  97
  98 /* not possible */
  99 int set_memory_nx(unsigned long addr, int numpages)
 100 {
 101         return 0;
 102 }
 103
 104 int set_memory_x(unsigned long addr, int numpages)
 105 {
 106         return 0;
 107 }
 108
 109 #ifdef CONFIG_DEBUG_PAGEALLOC
 110 void kernel_map_pages(struct page *page, int numpages, int enable)
 111 {
 112         unsigned long address;
 113         pgd_t *pgd;
 114         pud_t *pud;
 115         pmd_t *pmd;
 116         pte_t *pte;
 117         int i;
 118
 119         for (i = 0; i < numpages; i++) {
 120                 address = page_to_phys(page + i);
 121                 pgd = pgd_offset_k(address);
 122                 pud = pud_offset(pgd, address);
 123                 pmd = pmd_offset(pud, address);
 124                 pte = pte_offset_kernel(pmd, address);
 125                 if (!enable) {
 126                         __ptep_ipte(address, pte);
 127                         pte_val(*pte) = _PAGE_TYPE_EMPTY;
 128                         continue;
 129                 }
 130                 *pte = mk_pte_phys(address, __pgprot(_PAGE_TYPE_RW));
 131         }
 132 }
 133
 134 #ifdef CONFIG_HIBERNATION
 135 bool kernel_page_present(struct page *page)
 136 {
 137         unsigned long addr;
 138         int cc;
 139
 140         addr = page_to_phys(page);
 141         asm volatile(
 142                 "       lra     %1,0(%1)\n"
 143                 "       ipm     %0\n"
 144                 "       srl     %0,28"
 145                 : "=d" (cc), "+a" (addr) : : "cc");
 146         return cc == 0;
 147 }
 148 #endif /* CONFIG_HIBERNATION */
 149
 150 #endif /* CONFIG_DEBUG_PAGEALLOC */