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 #if PAGE_DEFAULT_KEY
  13 static inline unsigned long sske_frame(unsigned long addr, unsigned char skey)
  14 {
  15         asm volatile(".insn rrf,0xb22b0000,%[skey],%[addr],9,0"
  16                      : [addr] "+a" (addr) : [skey] "d" (skey));
  17         return addr;
  18 }
  19
  20 void __storage_key_init_range(unsigned long start, unsigned long end)
  21 {
  22         unsigned long boundary, size;
  23
  24         while (start < end) {
  25                 if (MACHINE_HAS_EDAT1) {
  26                         /* set storage keys for a 1MB frame */
  27                         size = 1UL << 20;
  28                         boundary = (start + size) & ~(size - 1);
  29                         if (boundary <= end) {
  30                                 do {
  31                                         start = sske_frame(start, PAGE_DEFAULT_KEY);
  32                                 } while (start < boundary);
  33                                 continue;
  34                         }
  35                 }
  36                 page_set_storage_key(start, PAGE_DEFAULT_KEY, 0);
  37                 start += PAGE_SIZE;
  38         }
  39 }
  40 #endif
  41
  42 static pte_t *walk_page_table(unsigned long addr)
  43 {
  44         pgd_t *pgdp;
  45         pud_t *pudp;
  46         pmd_t *pmdp;
  47         pte_t *ptep;
  48
  49         pgdp = pgd_offset_k(addr);
  50         if (pgd_none(*pgdp))
  51                 return NULL;
  52         pudp = pud_offset(pgdp, addr);
  53         if (pud_none(*pudp) || pud_large(*pudp))
  54                 return NULL;
  55         pmdp = pmd_offset(pudp, addr);
  56         if (pmd_none(*pmdp) || pmd_large(*pmdp))
  57                 return NULL;
  58         ptep = pte_offset_kernel(pmdp, addr);
  59         if (pte_none(*ptep))
  60                 return NULL;
  61         return ptep;
  62 }
  63
  64 static void change_page_attr(unsigned long addr, int numpages,
  65                              pte_t (*set) (pte_t))
  66 {
  67         pte_t *ptep, pte;
  68         int i;
  69
  70         for (i = 0; i < numpages; i++) {
  71                 ptep = walk_page_table(addr);
  72                 if (WARN_ON_ONCE(!ptep))
  73                         break;
  74                 pte = *ptep;
  75                 pte = set(pte);
  76                 __ptep_ipte(addr, ptep);
  77                 *ptep = pte;
  78                 addr += PAGE_SIZE;
  79         }
  80 }
  81
  82 int set_memory_ro(unsigned long addr, int numpages)
  83 {
  84         change_page_attr(addr, numpages, pte_wrprotect);
  85         return 0;
  86 }
  87
  88 int set_memory_rw(unsigned long addr, int numpages)
  89 {
  90         change_page_attr(addr, numpages, pte_mkwrite);
  91         return 0;
  92 }
  93
  94 /* not possible */
  95 int set_memory_nx(unsigned long addr, int numpages)
  96 {
  97         return 0;
  98 }
  99
 100 int set_memory_x(unsigned long addr, int numpages)
 101 {
 102         return 0;
 103 }
 104
 105 #ifdef CONFIG_DEBUG_PAGEALLOC
 106 void kernel_map_pages(struct page *page, int numpages, int enable)
 107 {
 108         unsigned long address;
 109         pgd_t *pgd;
 110         pud_t *pud;
 111         pmd_t *pmd;
 112         pte_t *pte;
 113         int i;
 114
 115         for (i = 0; i < numpages; i++) {
 116                 address = page_to_phys(page + i);
 117                 pgd = pgd_offset_k(address);
 118                 pud = pud_offset(pgd, address);
 119                 pmd = pmd_offset(pud, address);
 120                 pte = pte_offset_kernel(pmd, address);
 121                 if (!enable) {
 122                         __ptep_ipte(address, pte);
 123                         pte_val(*pte) = _PAGE_INVALID;
 124                         continue;
 125                 }
 126                 pte_val(*pte) = __pa(address);
 127         }
 128 }
 129
 130 #ifdef CONFIG_HIBERNATION
 131 bool kernel_page_present(struct page *page)
 132 {
 133         unsigned long addr;
 134         int cc;
 135
 136         addr = page_to_phys(page);
 137         asm volatile(
 138                 "       lra     %1,0(%1)\n"
 139                 "       ipm     %0\n"
 140                 "       srl     %0,28"
 141                 : "=d" (cc), "+a" (addr) : : "cc");
 142         return cc == 0;
 143 }
 144 #endif /* CONFIG_HIBERNATION */
 145
 146 #endif /* CONFIG_DEBUG_PAGEALLOC */