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