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hugetlb.h
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1 /*
2  * IBM System z Huge TLB Page Support for Kernel.
3  *
4  * Copyright IBM Corp. 2008
5  * Author(s): Gerald Schaefer <[email protected]>
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 void __pmd_csp(pmd_t *pmdp)
71 {
72  register unsigned long reg2 asm("2") = pmd_val(*pmdp);
73  register unsigned long reg3 asm("3") = pmd_val(*pmdp) |
74  _SEGMENT_ENTRY_INV;
75  register unsigned long reg4 asm("4") = ((unsigned long) pmdp) + 5;
76 
77  asm volatile(
78  " csp %1,%3"
79  : "=m" (*pmdp)
80  : "d" (reg2), "d" (reg3), "d" (reg4), "m" (*pmdp) : "cc");
81 }
82 
83 static inline void huge_ptep_invalidate(struct mm_struct *mm,
84  unsigned long address, pte_t *ptep)
85 {
86  pmd_t *pmdp = (pmd_t *) ptep;
87 
88  if (MACHINE_HAS_IDTE)
89  __pmd_idte(address, pmdp);
90  else
91  __pmd_csp(pmdp);
92  pmd_val(*pmdp) = _SEGMENT_ENTRY_INV | _SEGMENT_ENTRY;
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  huge_ptep_invalidate(mm, addr, ptep);
101  return pte;
102 }
103 
104 #define huge_ptep_set_access_flags(__vma, __addr, __ptep, __entry, __dirty) \
105 ({ \
106  int __changed = !pte_same(huge_ptep_get(__ptep), __entry); \
107  if (__changed) { \
108  huge_ptep_invalidate((__vma)->vm_mm, __addr, __ptep); \
109  set_huge_pte_at((__vma)->vm_mm, __addr, __ptep, __entry); \
110  } \
111  __changed; \
112 })
113 
114 #define huge_ptep_set_wrprotect(__mm, __addr, __ptep) \
115 ({ \
116  pte_t __pte = huge_ptep_get(__ptep); \
117  if (pte_write(__pte)) { \
118  huge_ptep_invalidate(__mm, __addr, __ptep); \
119  set_huge_pte_at(__mm, __addr, __ptep, \
120  huge_pte_wrprotect(__pte)); \
121  } \
122 })
123 
124 static inline void huge_ptep_clear_flush(struct vm_area_struct *vma,
125  unsigned long address, pte_t *ptep)
126 {
127  huge_ptep_invalidate(vma->vm_mm, address, ptep);
128 }
129 
130 #endif /* _ASM_S390_HUGETLB_H */
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