tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
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
10static DEFINE_XARRAY(mte_pages);
11
12void *mte_allocate_tag_storage(void)
13{
14 /* tags granule is 16 bytes, 2 tags stored per byte */
15 return kmalloc(MTE_PAGE_TAG_STORAGE, GFP_KERNEL);
16}
17
18void mte_free_tag_storage(char *storage)
19{
20 kfree(storage);
21}
22
23int mte_save_tags(struct page *page)
24{
25 void *tag_storage, *ret;
26
27 if (!page_mte_tagged(page))
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
49void 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;
55
56 if (try_page_mte_tagging(page)) {
57 mte_restore_page_tags(page_address(page), tags);
58 set_page_mte_tagged(page);
59 }
60}
61
62void mte_invalidate_tags(int type, pgoff_t offset)
63{
64 swp_entry_t entry = swp_entry(type, offset);
65 void *tags = xa_erase(&mte_pages, entry.val);
66
67 mte_free_tag_storage(tags);
68}
69
70void mte_invalidate_tags_area(int type)
71{
72 swp_entry_t entry = swp_entry(type, 0);
73 swp_entry_t last_entry = swp_entry(type + 1, 0);
74 void *tags;
75
76 XA_STATE(xa_state, &mte_pages, entry.val);
77
78 xa_lock(&mte_pages);
79 xas_for_each(&xa_state, tags, last_entry.val - 1) {
80 __xa_erase(&mte_pages, xa_state.xa_index);
81 mte_free_tag_storage(tags);
82 }
83 xa_unlock(&mte_pages);
84}