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1/* SPDX-License-Identifier: GPL-2.0 */
2#ifndef _S390_TLB_H
3#define _S390_TLB_H
4
5/*
6 * TLB flushing on s390 is complicated. The following requirement
7 * from the principles of operation is the most arduous:
8 *
9 * "A valid table entry must not be changed while it is attached
10 * to any CPU and may be used for translation by that CPU except to
11 * (1) invalidate the entry by using INVALIDATE PAGE TABLE ENTRY,
12 * or INVALIDATE DAT TABLE ENTRY, (2) alter bits 56-63 of a page
13 * table entry, or (3) make a change by means of a COMPARE AND SWAP
14 * AND PURGE instruction that purges the TLB."
15 *
16 * The modification of a pte of an active mm struct therefore is
17 * a two step process: i) invalidate the pte, ii) store the new pte.
18 * This is true for the page protection bit as well.
19 * The only possible optimization is to flush at the beginning of
20 * a tlb_gather_mmu cycle if the mm_struct is currently not in use.
21 *
22 * Pages used for the page tables is a different story. FIXME: more
23 */
24
25void __tlb_remove_table(void *_table);
26static inline void tlb_flush(struct mmu_gather *tlb);
27static inline bool __tlb_remove_page_size(struct mmu_gather *tlb,
28 struct page *page, bool delay_rmap, int page_size);
29static inline bool __tlb_remove_folio_pages(struct mmu_gather *tlb,
30 struct page *page, unsigned int nr_pages, bool delay_rmap);
31
32#define tlb_flush tlb_flush
33#define pte_free_tlb pte_free_tlb
34#define pmd_free_tlb pmd_free_tlb
35#define p4d_free_tlb p4d_free_tlb
36#define pud_free_tlb pud_free_tlb
37
38#include <asm/tlbflush.h>
39#include <asm-generic/tlb.h>
40
41/*
42 * Release the page cache reference for a pte removed by
43 * tlb_ptep_clear_flush. In both flush modes the tlb for a page cache page
44 * has already been freed, so just do free_page_and_swap_cache.
45 *
46 * s390 doesn't delay rmap removal.
47 */
48static inline bool __tlb_remove_page_size(struct mmu_gather *tlb,
49 struct page *page, bool delay_rmap, int page_size)
50{
51 VM_WARN_ON_ONCE(delay_rmap);
52
53 free_page_and_swap_cache(page);
54 return false;
55}
56
57static inline bool __tlb_remove_folio_pages(struct mmu_gather *tlb,
58 struct page *page, unsigned int nr_pages, bool delay_rmap)
59{
60 struct encoded_page *encoded_pages[] = {
61 encode_page(page, ENCODED_PAGE_BIT_NR_PAGES_NEXT),
62 encode_nr_pages(nr_pages),
63 };
64
65 VM_WARN_ON_ONCE(delay_rmap);
66 VM_WARN_ON_ONCE(page_folio(page) != page_folio(page + nr_pages - 1));
67
68 free_pages_and_swap_cache(encoded_pages, ARRAY_SIZE(encoded_pages));
69 return false;
70}
71
72static inline void tlb_flush(struct mmu_gather *tlb)
73{
74 __tlb_flush_mm_lazy(tlb->mm);
75}
76
77/*
78 * pte_free_tlb frees a pte table and clears the CRSTE for the
79 * page table from the tlb.
80 */
81static inline void pte_free_tlb(struct mmu_gather *tlb, pgtable_t pte,
82 unsigned long address)
83{
84 __tlb_adjust_range(tlb, address, PAGE_SIZE);
85 tlb->mm->context.flush_mm = 1;
86 tlb->freed_tables = 1;
87 tlb->cleared_pmds = 1;
88 if (mm_alloc_pgste(tlb->mm))
89 gmap_unlink(tlb->mm, (unsigned long *)pte, address);
90 tlb_remove_ptdesc(tlb, pte);
91}
92
93/*
94 * pmd_free_tlb frees a pmd table and clears the CRSTE for the
95 * segment table entry from the tlb.
96 * If the mm uses a two level page table the single pmd is freed
97 * as the pgd. pmd_free_tlb checks the asce_limit against 2GB
98 * to avoid the double free of the pmd in this case.
99 */
100static inline void pmd_free_tlb(struct mmu_gather *tlb, pmd_t *pmd,
101 unsigned long address)
102{
103 if (mm_pmd_folded(tlb->mm))
104 return;
105 pagetable_pmd_dtor(virt_to_ptdesc(pmd));
106 __tlb_adjust_range(tlb, address, PAGE_SIZE);
107 tlb->mm->context.flush_mm = 1;
108 tlb->freed_tables = 1;
109 tlb->cleared_puds = 1;
110 tlb_remove_ptdesc(tlb, pmd);
111}
112
113/*
114 * p4d_free_tlb frees a pud table and clears the CRSTE for the
115 * region second table entry from the tlb.
116 * If the mm uses a four level page table the single p4d is freed
117 * as the pgd. p4d_free_tlb checks the asce_limit against 8PB
118 * to avoid the double free of the p4d in this case.
119 */
120static inline void p4d_free_tlb(struct mmu_gather *tlb, p4d_t *p4d,
121 unsigned long address)
122{
123 if (mm_p4d_folded(tlb->mm))
124 return;
125 __tlb_adjust_range(tlb, address, PAGE_SIZE);
126 tlb->mm->context.flush_mm = 1;
127 tlb->freed_tables = 1;
128 tlb_remove_ptdesc(tlb, p4d);
129}
130
131/*
132 * pud_free_tlb frees a pud table and clears the CRSTE for the
133 * region third table entry from the tlb.
134 * If the mm uses a three level page table the single pud is freed
135 * as the pgd. pud_free_tlb checks the asce_limit against 4TB
136 * to avoid the double free of the pud in this case.
137 */
138static inline void pud_free_tlb(struct mmu_gather *tlb, pud_t *pud,
139 unsigned long address)
140{
141 if (mm_pud_folded(tlb->mm))
142 return;
143 tlb->mm->context.flush_mm = 1;
144 tlb->freed_tables = 1;
145 tlb->cleared_p4ds = 1;
146 tlb_remove_ptdesc(tlb, pud);
147}
148
149
150#endif /* _S390_TLB_H */
1#ifndef _S390_TLB_H
2#define _S390_TLB_H
3
4/*
5 * TLB flushing on s390 is complicated. The following requirement
6 * from the principles of operation is the most arduous:
7 *
8 * "A valid table entry must not be changed while it is attached
9 * to any CPU and may be used for translation by that CPU except to
10 * (1) invalidate the entry by using INVALIDATE PAGE TABLE ENTRY,
11 * or INVALIDATE DAT TABLE ENTRY, (2) alter bits 56-63 of a page
12 * table entry, or (3) make a change by means of a COMPARE AND SWAP
13 * AND PURGE instruction that purges the TLB."
14 *
15 * The modification of a pte of an active mm struct therefore is
16 * a two step process: i) invalidate the pte, ii) store the new pte.
17 * This is true for the page protection bit as well.
18 * The only possible optimization is to flush at the beginning of
19 * a tlb_gather_mmu cycle if the mm_struct is currently not in use.
20 *
21 * Pages used for the page tables is a different story. FIXME: more
22 */
23
24#include <linux/mm.h>
25#include <linux/pagemap.h>
26#include <linux/swap.h>
27#include <asm/processor.h>
28#include <asm/pgalloc.h>
29#include <asm/tlbflush.h>
30
31struct mmu_gather {
32 struct mm_struct *mm;
33 struct mmu_table_batch *batch;
34 unsigned int fullmm;
35 unsigned long start, end;
36};
37
38struct mmu_table_batch {
39 struct rcu_head rcu;
40 unsigned int nr;
41 void *tables[0];
42};
43
44#define MAX_TABLE_BATCH \
45 ((PAGE_SIZE - sizeof(struct mmu_table_batch)) / sizeof(void *))
46
47extern void tlb_table_flush(struct mmu_gather *tlb);
48extern void tlb_remove_table(struct mmu_gather *tlb, void *table);
49
50static inline void tlb_gather_mmu(struct mmu_gather *tlb,
51 struct mm_struct *mm,
52 unsigned long start,
53 unsigned long end)
54{
55 tlb->mm = mm;
56 tlb->start = start;
57 tlb->end = end;
58 tlb->fullmm = !(start | (end+1));
59 tlb->batch = NULL;
60}
61
62static inline void tlb_flush_mmu_tlbonly(struct mmu_gather *tlb)
63{
64 __tlb_flush_mm_lazy(tlb->mm);
65}
66
67static inline void tlb_flush_mmu_free(struct mmu_gather *tlb)
68{
69 tlb_table_flush(tlb);
70}
71
72
73static inline void tlb_flush_mmu(struct mmu_gather *tlb)
74{
75 tlb_flush_mmu_tlbonly(tlb);
76 tlb_flush_mmu_free(tlb);
77}
78
79static inline void tlb_finish_mmu(struct mmu_gather *tlb,
80 unsigned long start, unsigned long end)
81{
82 tlb_flush_mmu(tlb);
83}
84
85/*
86 * Release the page cache reference for a pte removed by
87 * tlb_ptep_clear_flush. In both flush modes the tlb for a page cache page
88 * has already been freed, so just do free_page_and_swap_cache.
89 */
90static inline bool __tlb_remove_page(struct mmu_gather *tlb, struct page *page)
91{
92 free_page_and_swap_cache(page);
93 return false; /* avoid calling tlb_flush_mmu */
94}
95
96static inline void tlb_remove_page(struct mmu_gather *tlb, struct page *page)
97{
98 free_page_and_swap_cache(page);
99}
100
101static inline bool __tlb_remove_page_size(struct mmu_gather *tlb,
102 struct page *page, int page_size)
103{
104 return __tlb_remove_page(tlb, page);
105}
106
107static inline void tlb_remove_page_size(struct mmu_gather *tlb,
108 struct page *page, int page_size)
109{
110 return tlb_remove_page(tlb, page);
111}
112
113/*
114 * pte_free_tlb frees a pte table and clears the CRSTE for the
115 * page table from the tlb.
116 */
117static inline void pte_free_tlb(struct mmu_gather *tlb, pgtable_t pte,
118 unsigned long address)
119{
120 page_table_free_rcu(tlb, (unsigned long *) pte, address);
121}
122
123/*
124 * pmd_free_tlb frees a pmd table and clears the CRSTE for the
125 * segment table entry from the tlb.
126 * If the mm uses a two level page table the single pmd is freed
127 * as the pgd. pmd_free_tlb checks the asce_limit against 2GB
128 * to avoid the double free of the pmd in this case.
129 */
130static inline void pmd_free_tlb(struct mmu_gather *tlb, pmd_t *pmd,
131 unsigned long address)
132{
133 if (tlb->mm->context.asce_limit <= (1UL << 31))
134 return;
135 pgtable_pmd_page_dtor(virt_to_page(pmd));
136 tlb_remove_table(tlb, pmd);
137}
138
139/*
140 * pud_free_tlb frees a pud table and clears the CRSTE for the
141 * region third table entry from the tlb.
142 * If the mm uses a three level page table the single pud is freed
143 * as the pgd. pud_free_tlb checks the asce_limit against 4TB
144 * to avoid the double free of the pud in this case.
145 */
146static inline void pud_free_tlb(struct mmu_gather *tlb, pud_t *pud,
147 unsigned long address)
148{
149 if (tlb->mm->context.asce_limit <= (1UL << 42))
150 return;
151 tlb_remove_table(tlb, pud);
152}
153
154#define tlb_start_vma(tlb, vma) do { } while (0)
155#define tlb_end_vma(tlb, vma) do { } while (0)
156#define tlb_remove_tlb_entry(tlb, ptep, addr) do { } while (0)
157#define tlb_remove_pmd_tlb_entry(tlb, pmdp, addr) do { } while (0)
158#define tlb_migrate_finish(mm) do { } while (0)
159#define tlb_remove_huge_tlb_entry(h, tlb, ptep, address) \
160 tlb_remove_tlb_entry(tlb, ptep, address)
161
162#define tlb_remove_check_page_size_change tlb_remove_check_page_size_change
163static inline void tlb_remove_check_page_size_change(struct mmu_gather *tlb,
164 unsigned int page_size)
165{
166}
167
168#endif /* _S390_TLB_H */