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 huge_pte_wrprotect(pte_t pte)
  41 {
  42         pte_val(pte) |= _PAGE_RO;
  43         return pte;
  44 }
  45
  46 static inline int huge_pte_none(pte_t pte)
  47 {
  48         return (pte_val(pte) & _SEGMENT_ENTRY_INV) &&
  49                 !(pte_val(pte) & _SEGMENT_ENTRY_RO);
  50 }
  51
  52 static inline pte_t huge_ptep_get(pte_t *ptep)
  53 {
  54         pte_t pte = *ptep;
  55         unsigned long mask;
  56
  57         if (!MACHINE_HAS_HPAGE) {
  58                 ptep = (pte_t *) (pte_val(pte) & _SEGMENT_ENTRY_ORIGIN);
  59                 if (ptep) {
  60                         mask = pte_val(pte) &
  61                                 (_SEGMENT_ENTRY_INV | _SEGMENT_ENTRY_RO);
  62                         pte = pte_mkhuge(*ptep);
  63                         pte_val(pte) |= mask;
  64                 }
  65         }
  66         return pte;
  67 }
  68
  69 static inline void __pmd_csp(pmd_t *pmdp)
  70 {
  71         register unsigned long reg2 asm("2") = pmd_val(*pmdp);
  72         register unsigned long reg3 asm("3") = pmd_val(*pmdp) |
  73                                                _SEGMENT_ENTRY_INV;
  74         register unsigned long reg4 asm("4") = ((unsigned long) pmdp) + 5;
  75
  76         asm volatile(
  77                 "       csp %1,%3"
  78                 : "=m" (*pmdp)
  79                 : "d" (reg2), "d" (reg3), "d" (reg4), "m" (*pmdp) : "cc");
  80         pmd_val(*pmdp) = _SEGMENT_ENTRY_INV | _SEGMENT_ENTRY;
  81 }
  82
  83 static inline void __pmd_idte(unsigned long address, pmd_t *pmdp)
  84 {
  85         unsigned long sto = (unsigned long) pmdp -
  86                                 pmd_index(address) * sizeof(pmd_t);
  87
  88         if (!(pmd_val(*pmdp) & _SEGMENT_ENTRY_INV)) {
  89                 asm volatile(
  90                         "       .insn   rrf,0xb98e0000,%2,%3,0,0"
  91                         : "=m" (*pmdp)
  92                         : "m" (*pmdp), "a" (sto),
  93                           "a" ((address & HPAGE_MASK))
  94                 );
  95         }
  96         pmd_val(*pmdp) = _SEGMENT_ENTRY_INV | _SEGMENT_ENTRY;
  97 }
  98
  99 static inline void huge_ptep_invalidate(struct mm_struct *mm,
 100                                         unsigned long address, pte_t *ptep)
 101 {
 102         pmd_t *pmdp = (pmd_t *) ptep;
 103
 104         if (MACHINE_HAS_IDTE)
 105                 __pmd_idte(address, pmdp);
 106         else
 107                 __pmd_csp(pmdp);
 108 }
 109
 110 static inline pte_t huge_ptep_get_and_clear(struct mm_struct *mm,
 111                                             unsigned long addr, pte_t *ptep)
 112 {
 113         pte_t pte = huge_ptep_get(ptep);
 114
 115         huge_ptep_invalidate(mm, addr, ptep);
 116         return pte;
 117 }
 118
 119 #define huge_ptep_set_access_flags(__vma, __addr, __ptep, __entry, __dirty) \
 120 ({                                                                          \
 121         int __changed = !pte_same(huge_ptep_get(__ptep), __entry);          \
 122         if (__changed) {                                                    \
 123                 huge_ptep_invalidate((__vma)->vm_mm, __addr, __ptep);       \
 124                 set_huge_pte_at((__vma)->vm_mm, __addr, __ptep, __entry);   \
 125         }                                                                   \
 126         __changed;                                                          \
 127 })
 128
 129 #define huge_ptep_set_wrprotect(__mm, __addr, __ptep)                   \
 130 ({                                                                      \
 131         pte_t __pte = huge_ptep_get(__ptep);                            \
 132         if (pte_write(__pte)) {                                         \
 133                 huge_ptep_invalidate(__mm, __addr, __ptep);             \
 134                 set_huge_pte_at(__mm, __addr, __ptep,                   \
 135                                 huge_pte_wrprotect(__pte));             \
 136         }                                                               \
 137 })
 138
 139 static inline void huge_ptep_clear_flush(struct vm_area_struct *vma,
 140                                          unsigned long address, pte_t *ptep)
 141 {
 142         huge_ptep_invalidate(vma->vm_mm, address, ptep);
 143 }
 144
 145 #endif /* _ASM_S390_HUGETLB_H */