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 pte_t huge_ptep_get_and_clear(struct mm_struct *mm,
  70                                             unsigned long addr, pte_t *ptep)
  71 {
  72         pte_t pte = huge_ptep_get(ptep);
  73
  74         mm->context.flush_mm = 1;
  75         pmd_clear((pmd_t *) ptep);
  76         return pte;
  77 }
  78
  79 static inline void __pmd_csp(pmd_t *pmdp)
  80 {
  81         register unsigned long reg2 asm("2") = pmd_val(*pmdp);
  82         register unsigned long reg3 asm("3") = pmd_val(*pmdp) |
  83                                                _SEGMENT_ENTRY_INV;
  84         register unsigned long reg4 asm("4") = ((unsigned long) pmdp) + 5;
  85
  86         asm volatile(
  87                 "       csp %1,%3"
  88                 : "=m" (*pmdp)
  89                 : "d" (reg2), "d" (reg3), "d" (reg4), "m" (*pmdp) : "cc");
  90         pmd_val(*pmdp) = _SEGMENT_ENTRY_INV | _SEGMENT_ENTRY;
  91 }
  92
  93 static inline void __pmd_idte(unsigned long address, pmd_t *pmdp)
  94 {
  95         unsigned long sto = (unsigned long) pmdp -
  96                                 pmd_index(address) * sizeof(pmd_t);
  97
  98         if (!(pmd_val(*pmdp) & _SEGMENT_ENTRY_INV)) {
  99                 asm volatile(
 100                         "       .insn   rrf,0xb98e0000,%2,%3,0,0"
 101                         : "=m" (*pmdp)
 102                         : "m" (*pmdp), "a" (sto),
 103                           "a" ((address & HPAGE_MASK))
 104                 );
 105         }
 106         pmd_val(*pmdp) = _SEGMENT_ENTRY_INV | _SEGMENT_ENTRY;
 107 }
 108
 109 static inline void huge_ptep_invalidate(struct mm_struct *mm,
 110                                         unsigned long address, pte_t *ptep)
 111 {
 112         pmd_t *pmdp = (pmd_t *) ptep;
 113
 114         if (MACHINE_HAS_IDTE)
 115                 __pmd_idte(address, pmdp);
 116         else
 117                 __pmd_csp(pmdp);
 118 }
 119
 120 #define huge_ptep_set_access_flags(__vma, __addr, __ptep, __entry, __dirty) \
 121 ({                                                                          \
 122         int __changed = !pte_same(huge_ptep_get(__ptep), __entry);          \
 123         if (__changed) {                                                    \
 124                 huge_ptep_invalidate((__vma)->vm_mm, __addr, __ptep);       \
 125                 set_huge_pte_at((__vma)->vm_mm, __addr, __ptep, __entry);   \
 126         }                                                                   \
 127         __changed;                                                          \
 128 })
 129
 130 #define huge_ptep_set_wrprotect(__mm, __addr, __ptep)                   \
 131 ({                                                                      \
 132         pte_t __pte = huge_ptep_get(__ptep);                            \
 133         if (pte_write(__pte)) {                                         \
 134                 (__mm)->context.flush_mm = 1;                           \
 135                 if (atomic_read(&(__mm)->context.attach_count) > 1 ||   \
 136                     (__mm) != current->active_mm)                       \
 137                         huge_ptep_invalidate(__mm, __addr, __ptep);     \
 138                 set_huge_pte_at(__mm, __addr, __ptep,                   \
 139                                 huge_pte_wrprotect(__pte));             \
 140         }                                                               \
 141 })
 142
 143 static inline void huge_ptep_clear_flush(struct vm_area_struct *vma,
 144                                          unsigned long address, pte_t *ptep)
 145 {
 146         huge_ptep_invalidate(vma->vm_mm, address, ptep);
 147 }
 148
 149 #endif /* _ASM_S390_HUGETLB_H */