1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Based on arch/arm/mm/copypage.c
4 *
5 * Copyright (C) 2002 Deep Blue Solutions Ltd, All Rights Reserved.
6 * Copyright (C) 2012 ARM Ltd.
7 */
8
9 #include <linux/bitops.h>
10 #include <linux/mm.h>
11
12 #include <asm/page.h>
13 #include <asm/cacheflush.h>
14 #include <asm/cpufeature.h>
15 #include <asm/mte.h>
16
copy_highpage(struct page * to,struct page * from)17 void copy_highpage(struct page *to, struct page *from)
18 {
19 struct page *kto = page_address(to);
20 struct page *kfrom = page_address(from);
21
22 copy_page(kto, kfrom);
23
24 if (system_supports_mte() && test_bit(PG_mte_tagged, &from->flags)) {
25 set_bit(PG_mte_tagged, &to->flags);
26 page_kasan_tag_reset(to);
27 /*
28 * We need smp_wmb() in between setting the flags and clearing the
29 * tags because if another thread reads page->flags and builds a
30 * tagged address out of it, there is an actual dependency to the
31 * memory access, but on the current thread we do not guarantee that
32 * the new page->flags are visible before the tags were updated.
33 */
34 smp_wmb();
35 mte_copy_page_tags(kto, kfrom);
36 }
37 }
38 EXPORT_SYMBOL(copy_highpage);
39
copy_user_highpage(struct page * to,struct page * from,unsigned long vaddr,struct vm_area_struct * vma)40 void copy_user_highpage(struct page *to, struct page *from,
41 unsigned long vaddr, struct vm_area_struct *vma)
42 {
43 copy_highpage(to, from);
44 flush_dcache_page(to);
45 }
46 EXPORT_SYMBOL_GPL(copy_user_highpage);
47