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 #define hugepages_supported()                   (MACHINE_HAS_HPAGE)
  18
  19 void set_huge_pte_at(struct mm_struct *mm, unsigned long addr,
  20                      pte_t *ptep, pte_t pte);
  21
  22 /*
  23  * If the arch doesn't supply something else, assume that hugepage
  24  * size aligned regions are ok without further preparation.
  25  */
  26 static inline int prepare_hugepage_range(struct file *file,
  27                         unsigned long addr, unsigned long len)
  28 {
  29         if (len & ~HPAGE_MASK)
  30                 return -EINVAL;
  31         if (addr & ~HPAGE_MASK)
  32                 return -EINVAL;
  33         return 0;
  34 }
  35
  36 #define hugetlb_prefault_arch_hook(mm)          do { } while (0)
  37 #define arch_clear_hugepage_flags(page)         do { } while (0)
  38
  39 int arch_prepare_hugepage(struct page *page);
  40 void arch_release_hugepage(struct page *page);
  41
  42 static inline pte_t huge_pte_wrprotect(pte_t pte)
  43 {
  44         pte_val(pte) |= _PAGE_RO;
  45         return pte;
  46 }
  47
  48 static inline int huge_pte_none(pte_t pte)
  49 {
  50         return (pte_val(pte) & _SEGMENT_ENTRY_INV) &&
  51                 !(pte_val(pte) & _SEGMENT_ENTRY_RO);
  52 }
  53
  54 static inline pte_t huge_ptep_get(pte_t *ptep)
  55 {
  56         pte_t pte = *ptep;
  57         unsigned long mask;
  58
  59         if (!MACHINE_HAS_HPAGE) {
  60                 ptep = (pte_t *) (pte_val(pte) & _SEGMENT_ENTRY_ORIGIN);
  61                 if (ptep) {
  62                         mask = pte_val(pte) &
  63                                 (_SEGMENT_ENTRY_INV | _SEGMENT_ENTRY_RO);
  64                         pte = pte_mkhuge(*ptep);
  65                         pte_val(pte) |= mask;
  66                 }
  67         }
  68         return pte;
  69 }
  70
  71 static inline pte_t huge_ptep_get_and_clear(struct mm_struct *mm,
  72                                             unsigned long addr, pte_t *ptep)
  73 {
  74         pte_t pte = huge_ptep_get(ptep);
  75
  76         mm->context.flush_mm = 1;
  77         pmd_clear((pmd_t *) ptep);
  78         return pte;
  79 }
  80
  81 static inline void __pmd_csp(pmd_t *pmdp)
  82 {
  83         register unsigned long reg2 asm("2") = pmd_val(*pmdp);
  84         register unsigned long reg3 asm("3") = pmd_val(*pmdp) |
  85                                                _SEGMENT_ENTRY_INV;
  86         register unsigned long reg4 asm("4") = ((unsigned long) pmdp) + 5;
  87
  88         asm volatile(
  89                 "       csp %1,%3"
  90                 : "=m" (*pmdp)
  91                 : "d" (reg2), "d" (reg3), "d" (reg4), "m" (*pmdp) : "cc");
  92         pmd_val(*pmdp) = _SEGMENT_ENTRY_INV | _SEGMENT_ENTRY;
  93 }
  94
  95 static inline void __pmd_idte(unsigned long address, pmd_t *pmdp)
  96 {
  97         unsigned long sto = (unsigned long) pmdp -
  98                                 pmd_index(address) * sizeof(pmd_t);
  99
 100         if (!(pmd_val(*pmdp) & _SEGMENT_ENTRY_INV)) {
 101                 asm volatile(
 102                         "       .insn   rrf,0xb98e0000,%2,%3,0,0"
 103                         : "=m" (*pmdp)
 104                         : "m" (*pmdp), "a" (sto),
 105                           "a" ((address & HPAGE_MASK))
 106                 );
 107         }
 108         pmd_val(*pmdp) = _SEGMENT_ENTRY_INV | _SEGMENT_ENTRY;
 109 }
 110
 111 static inline void huge_ptep_invalidate(struct mm_struct *mm,
 112                                         unsigned long address, pte_t *ptep)
 113 {
 114         pmd_t *pmdp = (pmd_t *) ptep;
 115
 116         if (MACHINE_HAS_IDTE)
 117                 __pmd_idte(address, pmdp);
 118         else
 119                 __pmd_csp(pmdp);
 120 }
 121
 122 #define huge_ptep_set_access_flags(__vma, __addr, __ptep, __entry, __dirty) \
 123 ({                                                                          \
 124         int __changed = !pte_same(huge_ptep_get(__ptep), __entry);          \
 125         if (__changed) {                                                    \
 126                 huge_ptep_invalidate((__vma)->vm_mm, __addr, __ptep);       \
 127                 set_huge_pte_at((__vma)->vm_mm, __addr, __ptep, __entry);   \
 128         }                                                                   \
 129         __changed;                                                          \
 130 })
 131
 132 #define huge_ptep_set_wrprotect(__mm, __addr, __ptep)                   \
 133 ({                                                                      \
 134         pte_t __pte = huge_ptep_get(__ptep);                            \
 135         if (pte_write(__pte)) {                                         \
 136                 (__mm)->context.flush_mm = 1;                           \
 137                 if (atomic_read(&(__mm)->context.attach_count) > 1 ||   \
 138                     (__mm) != current->active_mm)                       \
 139                         huge_ptep_invalidate(__mm, __addr, __ptep);     \
 140                 set_huge_pte_at(__mm, __addr, __ptep,                   \
 141                                 huge_pte_wrprotect(__pte));             \
 142         }                                                               \
 143 })
 144
 145 static inline void huge_ptep_clear_flush(struct vm_area_struct *vma,
 146                                          unsigned long address, pte_t *ptep)
 147 {
 148         huge_ptep_invalidate(vma->vm_mm, address, ptep);
 149 }
 150
 151 #endif /* _ASM_S390_HUGETLB_H */