arch/arm64/mm/copypage.c

   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);