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 */
151