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 #define arch_clear_hugepage_flags(page)         do { } while (0)
  37
  38 int arch_prepare_hugepage(struct page *page);
  39 void arch_release_hugepage(struct page *page);
  40
  41 static inline pte_t huge_pte_wrprotect(pte_t pte)
  42 {
  43         pte_val(pte) |= _PAGE_RO;
  44         return pte;
  45 }
  46
  47 static inline int huge_pte_none(pte_t pte)
  48 {
  49         return (pte_val(pte) & _SEGMENT_ENTRY_INV) &&
  50                 !(pte_val(pte) & _SEGMENT_ENTRY_RO);
  51 }
  52
  53 static inline pte_t huge_ptep_get(pte_t *ptep)
  54 {
  55         pte_t pte = *ptep;
  56         unsigned long mask;
  57
  58         if (!MACHINE_HAS_HPAGE) {
  59                 ptep = (pte_t *) (pte_val(pte) & _SEGMENT_ENTRY_ORIGIN);
  60                 if (ptep) {
  61                         mask = pte_val(pte) &
  62                                 (_SEGMENT_ENTRY_INV | _SEGMENT_ENTRY_RO);
  63                         pte = pte_mkhuge(*ptep);
  64                         pte_val(pte) |= mask;
  65                 }
  66         }
  67         return pte;
  68 }
  69
  70 static inline pte_t huge_ptep_get_and_clear(struct mm_struct *mm,
  71                                             unsigned long addr, pte_t *ptep)
  72 {
  73         pte_t pte = huge_ptep_get(ptep);
  74
  75         mm->context.flush_mm = 1;
  76         pmd_clear((pmd_t *) ptep);
  77         return pte;
  78 }
  79
  80 static inline void __pmd_csp(pmd_t *pmdp)
  81 {
  82         register unsigned long reg2 asm("2") = pmd_val(*pmdp);
  83         register unsigned long reg3 asm("3") = pmd_val(*pmdp) |
  84                                                _SEGMENT_ENTRY_INV;
  85         register unsigned long reg4 asm("4") = ((unsigned long) pmdp) + 5;
  86
  87         asm volatile(
  88                 "       csp %1,%3"
  89                 : "=m" (*pmdp)
  90                 : "d" (reg2), "d" (reg3), "d" (reg4), "m" (*pmdp) : "cc");
  91         pmd_val(*pmdp) = _SEGMENT_ENTRY_INV | _SEGMENT_ENTRY;
  92 }
  93
  94 static inline void __pmd_idte(unsigned long address, pmd_t *pmdp)
  95 {
  96         unsigned long sto = (unsigned long) pmdp -
  97                                 pmd_index(address) * sizeof(pmd_t);
  98
  99         if (!(pmd_val(*pmdp) & _SEGMENT_ENTRY_INV)) {
 100                 asm volatile(
 101                         "       .insn   rrf,0xb98e0000,%2,%3,0,0"
 102                         : "=m" (*pmdp)
 103                         : "m" (*pmdp), "a" (sto),
 104                           "a" ((address & HPAGE_MASK))
 105                 );
 106         }
 107         pmd_val(*pmdp) = _SEGMENT_ENTRY_INV | _SEGMENT_ENTRY;
 108 }
 109
 110 static inline void huge_ptep_invalidate(struct mm_struct *mm,
 111                                         unsigned long address, pte_t *ptep)
 112 {
 113         pmd_t *pmdp = (pmd_t *) ptep;
 114
 115         if (MACHINE_HAS_IDTE)
 116                 __pmd_idte(address, pmdp);
 117         else
 118                 __pmd_csp(pmdp);
 119 }
 120
 121 #define huge_ptep_set_access_flags(__vma, __addr, __ptep, __entry, __dirty) \
 122 ({                                                                          \
 123         int __changed = !pte_same(huge_ptep_get(__ptep), __entry);          \
 124         if (__changed) {                                                    \
 125                 huge_ptep_invalidate((__vma)->vm_mm, __addr, __ptep);       \
 126                 set_huge_pte_at((__vma)->vm_mm, __addr, __ptep, __entry);   \
 127         }                                                                   \
 128         __changed;                                                          \
 129 })
 130
 131 #define huge_ptep_set_wrprotect(__mm, __addr, __ptep)                   \
 132 ({                                                                      \
 133         pte_t __pte = huge_ptep_get(__ptep);                            \
 134         if (pte_write(__pte)) {                                         \
 135                 (__mm)->context.flush_mm = 1;                           \
 136                 if (atomic_read(&(__mm)->context.attach_count) > 1 ||   \
 137                     (__mm) != current->active_mm)                       \
 138                         huge_ptep_invalidate(__mm, __addr, __ptep);     \
 139                 set_huge_pte_at(__mm, __addr, __ptep,                   \
 140                                 huge_pte_wrprotect(__pte));             \
 141         }                                                               \
 142 })
 143
 144 static inline void huge_ptep_clear_flush(struct vm_area_struct *vma,
 145                                          unsigned long address, pte_t *ptep)
 146 {
 147         huge_ptep_invalidate(vma->vm_mm, address, ptep);
 148 }
 149
 150 #endif /* _ASM_S390_HUGETLB_H */