arch/s390/include/asm/hugetlb.h

   1 /*
   2  *  IBM System z Huge TLB Page Support for Kernel.
   3  *
   4  *    Copyright IBM Corp. 2008
   5  *    Author(s): Gerald Schaefer <gerald.schaefer@de.ibm.com>
   6  */
   7
   8 #ifndef _ASM_S390_HUGETLB_H
   9 #define _ASM_S390_HUGETLB_H
  10
  11 #include <asm/page.h>
  12 #include <asm/pgtable.h>
  13
  14
  15 #define is_hugepage_only_range(mm, addr, len)   0
  16 #define hugetlb_free_pgd_range                  free_pgd_range
  17
  18 void set_huge_pte_at(struct mm_struct *mm, unsigned long addr,
  19                      pte_t *ptep, pte_t pte);
  20
  21 /*
  22  * If the arch doesn't supply something else, assume that hugepage
  23  * size aligned regions are ok without further preparation.
  24  */
  25 static inline int prepare_hugepage_range(struct file *file,
  26                         unsigned long addr, unsigned long len)
  27 {
  28         if (len & ~HPAGE_MASK)
  29                 return -EINVAL;
  30         if (addr & ~HPAGE_MASK)
  31                 return -EINVAL;
  32         return 0;
  33 }
  34
  35 #define hugetlb_prefault_arch_hook(mm)          do { } while (0)
  36
  37 int arch_prepare_hugepage(struct page *page);
  38 void arch_release_hugepage(struct page *page);
  39
  40 static inline pte_t pte_mkhuge(pte_t pte)
  41 {
  42         /*
  43          * PROT_NONE needs to be remapped from the pte type to the ste type.
  44          * The HW invalid bit is also different for pte and ste. The pte
  45          * invalid bit happens to be the same as the ste _SEGMENT_ENTRY_LARGE
  46          * bit, so we don't have to clear it.
  47          */
  48         if (pte_val(pte) & _PAGE_INVALID) {
  49                 if (pte_val(pte) & _PAGE_SWT)
  50                         pte_val(pte) |= _HPAGE_TYPE_NONE;
  51                 pte_val(pte) |= _SEGMENT_ENTRY_INV;
  52         }
  53         /*
  54          * Clear SW pte bits SWT and SWX, there are no SW bits in a segment
  55          * table entry.
  56          */
  57         pte_val(pte) &= ~(_PAGE_SWT | _PAGE_SWX);
  58         /*
  59          * Also set the change-override bit because we don't need dirty bit
  60          * tracking for hugetlbfs pages.
  61          */
  62         pte_val(pte) |= (_SEGMENT_ENTRY_LARGE | _SEGMENT_ENTRY_CO);
  63         return pte;
  64 }
  65
  66 static inline pte_t huge_pte_wrprotect(pte_t pte)
  67 {
  68         pte_val(pte) |= _PAGE_RO;
  69         return pte;
  70 }
  71
  72 static inline int huge_pte_none(pte_t pte)
  73 {
  74         return (pte_val(pte) & _SEGMENT_ENTRY_INV) &&
  75                 !(pte_val(pte) & _SEGMENT_ENTRY_RO);
  76 }
  77
  78 static inline pte_t huge_ptep_get(pte_t *ptep)
  79 {
  80         pte_t pte = *ptep;
  81         unsigned long mask;
  82
  83         if (!MACHINE_HAS_HPAGE) {
  84                 ptep = (pte_t *) (pte_val(pte) & _SEGMENT_ENTRY_ORIGIN);
  85                 if (ptep) {
  86                         mask = pte_val(pte) &
  87                                 (_SEGMENT_ENTRY_INV | _SEGMENT_ENTRY_RO);
  88                         pte = pte_mkhuge(*ptep);
  89                         pte_val(pte) |= mask;
  90                 }
  91         }
  92         return pte;
  93 }
  94
  95 static inline pte_t huge_ptep_get_and_clear(struct mm_struct *mm,
  96                                             unsigned long addr, pte_t *ptep)
  97 {
  98         pte_t pte = huge_ptep_get(ptep);
  99
 100         pmd_clear((pmd_t *) ptep);
 101         return pte;
 102 }
 103
 104 static inline void __pmd_csp(pmd_t *pmdp)
 105 {
 106         register unsigned long reg2 asm("2") = pmd_val(*pmdp);
 107         register unsigned long reg3 asm("3") = pmd_val(*pmdp) |
 108                                                _SEGMENT_ENTRY_INV;
 109         register unsigned long reg4 asm("4") = ((unsigned long) pmdp) + 5;
 110
 111         asm volatile(
 112                 "       csp %1,%3"
 113                 : "=m" (*pmdp)
 114                 : "d" (reg2), "d" (reg3), "d" (reg4), "m" (*pmdp) : "cc");
 115         pmd_val(*pmdp) = _SEGMENT_ENTRY_INV | _SEGMENT_ENTRY;
 116 }
 117
 118 static inline void __pmd_idte(unsigned long address, pmd_t *pmdp)
 119 {
 120         unsigned long sto = (unsigned long) pmdp -
 121                                 pmd_index(address) * sizeof(pmd_t);
 122
 123         if (!(pmd_val(*pmdp) & _SEGMENT_ENTRY_INV)) {
 124                 asm volatile(
 125                         "       .insn   rrf,0xb98e0000,%2,%3,0,0"
 126                         : "=m" (*pmdp)
 127                         : "m" (*pmdp), "a" (sto),
 128                           "a" ((address & HPAGE_MASK))
 129                 );
 130         }
 131         pmd_val(*pmdp) = _SEGMENT_ENTRY_INV | _SEGMENT_ENTRY;
 132 }
 133
 134 static inline void huge_ptep_invalidate(struct mm_struct *mm,
 135                                         unsigned long address, pte_t *ptep)
 136 {
 137         pmd_t *pmdp = (pmd_t *) ptep;
 138
 139         if (!MACHINE_HAS_IDTE) {
 140                 __pmd_csp(pmdp);
 141                 if (mm->context.noexec) {
 142                         pmdp = get_shadow_table(pmdp);
 143                         __pmd_csp(pmdp);
 144                 }
 145                 return;
 146         }
 147
 148         __pmd_idte(address, pmdp);
 149         if (mm->context.noexec) {
 150                 pmdp = get_shadow_table(pmdp);
 151                 __pmd_idte(address, pmdp);
 152         }
 153         return;
 154 }
 155
 156 #define huge_ptep_set_access_flags(__vma, __addr, __ptep, __entry, __dirty) \
 157 ({                                                                          \
 158         int __changed = !pte_same(huge_ptep_get(__ptep), __entry);          \
 159         if (__changed) {                                                    \
 160                 huge_ptep_invalidate((__vma)->vm_mm, __addr, __ptep);       \
 161                 set_huge_pte_at((__vma)->vm_mm, __addr, __ptep, __entry);   \
 162         }                                                                   \
 163         __changed;                                                          \
 164 })
 165
 166 #define huge_ptep_set_wrprotect(__mm, __addr, __ptep)                   \
 167 ({                                                                      \
 168         pte_t __pte = huge_ptep_get(__ptep);                            \
 169         if (pte_write(__pte)) {                                         \
 170                 if (atomic_read(&(__mm)->mm_users) > 1 ||               \
 171                     (__mm) != current->active_mm)                       \
 172                         huge_ptep_invalidate(__mm, __addr, __ptep);     \
 173                 set_huge_pte_at(__mm, __addr, __ptep,                   \
 174                                 huge_pte_wrprotect(__pte));             \
 175         }                                                               \
 176 })
 177
 178 static inline void huge_ptep_clear_flush(struct vm_area_struct *vma,
 179                                          unsigned long address, pte_t *ptep)
 180 {
 181         huge_ptep_invalidate(vma->vm_mm, address, ptep);
 182 }
 183
 184 #endif /* _ASM_S390_HUGETLB_H */