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
18void 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 */
25static 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
37int arch_prepare_hugepage(struct page *page);
38void arch_release_hugepage(struct page *page);
39
40static inline pte_t huge_pte_wrprotect(pte_t pte)
41{
42	pte_val(pte) |= _PAGE_RO;
43	return pte;
44}
45
46static 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
52static 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
69static 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
79static 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
93static 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
109static 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
143static 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 */
150