1 // SPDX-License-Identifier: GPL-2.0-only
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>
10 static DEFINE_XARRAY(mte_pages);
12 void *mte_allocate_tag_storage(void)
14 /* tags granule is 16 bytes, 2 tags stored per byte */
15 return kmalloc(MTE_PAGE_TAG_STORAGE, GFP_KERNEL);
18 void mte_free_tag_storage(char *storage)
23 int mte_save_tags(struct page *page)
25 void *tag_storage, *ret;
27 if (!page_mte_tagged(page))
30 tag_storage = mte_allocate_tag_storage();
34 mte_save_page_tags(page_address(page), tag_storage);
36 /* lookup the swap entry.val from the page */
37 ret = xa_store(&mte_pages, page_swap_entry(page).val, tag_storage,
39 if (WARN(xa_is_err(ret), "Failed to store MTE tags")) {
40 mte_free_tag_storage(tag_storage);
43 /* Entry is being replaced, free the old entry */
44 mte_free_tag_storage(ret);
50 void mte_restore_tags(swp_entry_t entry, struct page *page)
52 void *tags = xa_load(&mte_pages, entry.val);
57 if (try_page_mte_tagging(page)) {
58 mte_restore_page_tags(page_address(page), tags);
59 set_page_mte_tagged(page);
63 void mte_invalidate_tags(int type, pgoff_t offset)
65 swp_entry_t entry = swp_entry(type, offset);
66 void *tags = xa_erase(&mte_pages, entry.val);
68 mte_free_tag_storage(tags);
71 void mte_invalidate_tags_area(int type)
73 swp_entry_t entry = swp_entry(type, 0);
74 swp_entry_t last_entry = swp_entry(type + 1, 0);
77 XA_STATE(xa_state, &mte_pages, entry.val);
80 xas_for_each(&xa_state, tags, last_entry.val - 1) {
81 __xa_erase(&mte_pages, xa_state.xa_index);
82 mte_free_tag_storage(tags);
84 xa_unlock(&mte_pages);