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 */ 15 return kmalloc(MTE_PAGE_TAG_STORAGE, GFP_KERNEL); 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 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 49 void 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 62 void 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 70 void 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 } 85