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 */