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36943aba SP |
1 | // SPDX-License-Identifier: GPL-2.0-only |
2 | ||
3 | #include <linux/pagemap.h> | |
4 | #include <linux/xarray.h> | |
5 | #include <linux/slab.h> | |
6 | #include <linux/swap.h> | |
7 | #include <linux/swapops.h> | |
8 | #include <asm/mte.h> | |
9 | ||
10 | static DEFINE_XARRAY(mte_pages); | |
11 | ||
12 | void *mte_allocate_tag_storage(void) | |
13 | { | |
14 | /* tags granule is 16 bytes, 2 tags stored per byte */ | |
ab1e435c | 15 | return kmalloc(MTE_PAGE_TAG_STORAGE, GFP_KERNEL); |
36943aba SP |
16 | } |
17 | ||
18 | void mte_free_tag_storage(char *storage) | |
19 | { | |
20 | kfree(storage); | |
21 | } | |
22 | ||
23 | int mte_save_tags(struct page *page) | |
24 | { | |
25 | void *tag_storage, *ret; | |
26 | ||
e059853d | 27 | if (!page_mte_tagged(page)) |
36943aba SP |
28 | return 0; |
29 | ||
30 | tag_storage = mte_allocate_tag_storage(); | |
31 | if (!tag_storage) | |
32 | return -ENOMEM; | |
33 | ||
34 | mte_save_page_tags(page_address(page), tag_storage); | |
35 | ||
cfeed8ff DH |
36 | /* lookup the swap entry.val from the page */ |
37 | ret = xa_store(&mte_pages, page_swap_entry(page).val, tag_storage, | |
38 | GFP_KERNEL); | |
36943aba SP |
39 | if (WARN(xa_is_err(ret), "Failed to store MTE tags")) { |
40 | mte_free_tag_storage(tag_storage); | |
41 | return xa_err(ret); | |
42 | } else if (ret) { | |
43 | /* Entry is being replaced, free the old entry */ | |
44 | mte_free_tag_storage(ret); | |
45 | } | |
46 | ||
47 | return 0; | |
48 | } | |
49 | ||
d77e59a8 | 50 | void mte_restore_tags(swp_entry_t entry, struct page *page) |
36943aba SP |
51 | { |
52 | void *tags = xa_load(&mte_pages, entry.val); | |
53 | ||
54 | if (!tags) | |
d77e59a8 | 55 | return; |
36943aba | 56 | |
d77e59a8 | 57 | if (try_page_mte_tagging(page)) { |
a8e5e514 | 58 | mte_restore_page_tags(page_address(page), tags); |
d77e59a8 CM |
59 | set_page_mte_tagged(page); |
60 | } | |
36943aba SP |
61 | } |
62 | ||
63 | void mte_invalidate_tags(int type, pgoff_t offset) | |
64 | { | |
65 | swp_entry_t entry = swp_entry(type, offset); | |
66 | void *tags = xa_erase(&mte_pages, entry.val); | |
67 | ||
68 | mte_free_tag_storage(tags); | |
69 | } | |
70 | ||
f238b8c3 BS |
71 | static inline void __mte_invalidate_tags(struct page *page) |
72 | { | |
73 | swp_entry_t entry = page_swap_entry(page); | |
74 | ||
75 | mte_invalidate_tags(swp_type(entry), swp_offset(entry)); | |
76 | } | |
77 | ||
36943aba SP |
78 | void mte_invalidate_tags_area(int type) |
79 | { | |
80 | swp_entry_t entry = swp_entry(type, 0); | |
81 | swp_entry_t last_entry = swp_entry(type + 1, 0); | |
82 | void *tags; | |
83 | ||
84 | XA_STATE(xa_state, &mte_pages, entry.val); | |
85 | ||
86 | xa_lock(&mte_pages); | |
87 | xas_for_each(&xa_state, tags, last_entry.val - 1) { | |
88 | __xa_erase(&mte_pages, xa_state.xa_index); | |
89 | mte_free_tag_storage(tags); | |
90 | } | |
91 | xa_unlock(&mte_pages); | |
92 | } | |
f238b8c3 BS |
93 | |
94 | int arch_prepare_to_swap(struct folio *folio) | |
95 | { | |
96 | long i, nr; | |
97 | int err; | |
98 | ||
99 | if (!system_supports_mte()) | |
100 | return 0; | |
101 | ||
102 | nr = folio_nr_pages(folio); | |
103 | ||
104 | for (i = 0; i < nr; i++) { | |
105 | err = mte_save_tags(folio_page(folio, i)); | |
106 | if (err) | |
107 | goto out; | |
108 | } | |
109 | return 0; | |
110 | ||
111 | out: | |
112 | while (i--) | |
113 | __mte_invalidate_tags(folio_page(folio, i)); | |
114 | return err; | |
115 | } | |
116 | ||
117 | void arch_swap_restore(swp_entry_t entry, struct folio *folio) | |
118 | { | |
119 | long i, nr; | |
120 | ||
121 | if (!system_supports_mte()) | |
122 | return; | |
123 | ||
124 | nr = folio_nr_pages(folio); | |
125 | ||
126 | for (i = 0; i < nr; i++) { | |
127 | mte_restore_tags(entry, folio_page(folio, i)); | |
128 | entry.val++; | |
129 | } | |
130 | } |