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
mte_allocate_tag_storage(void)12 void *mte_allocate_tag_storage(void)
13 {
14 /* tags granule is 16 bytes, 2 tags stored per byte */
15 return kmalloc(PAGE_SIZE / 16 / 2, GFP_KERNEL);
16 }
17
mte_free_tag_storage(char * storage)18 void mte_free_tag_storage(char *storage)
19 {
20 kfree(storage);
21 }
22
mte_save_tags(struct page * page)23 int mte_save_tags(struct page *page)
24 {
25 void *tag_storage, *ret;
26
27 if (!test_bit(PG_mte_tagged, &page->flags))
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
36 /* page_private contains the swap entry.val set in do_swap_page */
37 ret = xa_store(&mte_pages, page_private(page), tag_storage, GFP_KERNEL);
38 if (WARN(xa_is_err(ret), "Failed to store MTE tags")) {
39 mte_free_tag_storage(tag_storage);
40 return xa_err(ret);
41 } else if (ret) {
42 /* Entry is being replaced, free the old entry */
43 mte_free_tag_storage(ret);
44 }
45
46 return 0;
47 }
48
mte_restore_tags(swp_entry_t entry,struct page * page)49 bool mte_restore_tags(swp_entry_t entry, struct page *page)
50 {
51 void *tags = xa_load(&mte_pages, entry.val);
52
53 if (!tags)
54 return false;
55
56 mte_restore_page_tags(page_address(page), tags);
57
58 return true;
59 }
60
mte_invalidate_tags(int type,pgoff_t offset)61 void mte_invalidate_tags(int type, pgoff_t offset)
62 {
63 swp_entry_t entry = swp_entry(type, offset);
64 void *tags = xa_erase(&mte_pages, entry.val);
65
66 mte_free_tag_storage(tags);
67 }
68
mte_invalidate_tags_area(int type)69 void mte_invalidate_tags_area(int type)
70 {
71 swp_entry_t entry = swp_entry(type, 0);
72 swp_entry_t last_entry = swp_entry(type + 1, 0);
73 void *tags;
74
75 XA_STATE(xa_state, &mte_pages, entry.val);
76
77 xa_lock(&mte_pages);
78 xas_for_each(&xa_state, tags, last_entry.val - 1) {
79 __xa_erase(&mte_pages, xa_state.xa_index);
80 mte_free_tag_storage(tags);
81 }
82 xa_unlock(&mte_pages);
83 }
84
