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 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 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