LXR linux/arch/arm/mm/copypage-v6.c

   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 *  linux/arch/arm/mm/copypage-v6.c
   4 *
   5 *  Copyright (C) 2002 Deep Blue Solutions Ltd, All Rights Reserved.
   6 */
   7#include <linux/init.h>
   8#include <linux/spinlock.h>
   9#include <linux/mm.h>
  10#include <linux/highmem.h>
  11
  12#include <asm/pgtable.h>
  13#include <asm/shmparam.h>
  14#include <asm/tlbflush.h>
  15#include <asm/cacheflush.h>
  16#include <asm/cachetype.h>
  17
  18#include "mm.h"
  19
  20#if SHMLBA > 16384
  21#error FIX ME
  22#endif
  23
  24static DEFINE_RAW_SPINLOCK(v6_lock);
  25
  26/*
  27 * Copy the user page.  No aliasing to deal with so we can just
  28 * attack the kernel's existing mapping of these pages.
  29 */
  30static void v6_copy_user_highpage_nonaliasing(struct page *to,
  31        struct page *from, unsigned long vaddr, struct vm_area_struct *vma)
  32{
  33        void *kto, *kfrom;
  34
  35        kfrom = kmap_atomic(from);
  36        kto = kmap_atomic(to);
  37        copy_page(kto, kfrom);
  38        kunmap_atomic(kto);
  39        kunmap_atomic(kfrom);
  40}
  41
  42/*
  43 * Clear the user page.  No aliasing to deal with so we can just
  44 * attack the kernel's existing mapping of this page.
  45 */
  46static void v6_clear_user_highpage_nonaliasing(struct page *page, unsigned long vaddr)
  47{
  48        void *kaddr = kmap_atomic(page);
  49        clear_page(kaddr);
  50        kunmap_atomic(kaddr);
  51}
  52
  53/*
  54 * Discard data in the kernel mapping for the new page.
  55 * FIXME: needs this MCRR to be supported.
  56 */
  57static void discard_old_kernel_data(void *kto)
  58{
  59        __asm__("mcrr   p15, 0, %1, %0, c6      @ 0xec401f06"
  60           :
  61           : "r" (kto),
  62             "r" ((unsigned long)kto + PAGE_SIZE - 1)
  63           : "cc");
  64}
  65
  66/*
  67 * Copy the page, taking account of the cache colour.
  68 */
  69static void v6_copy_user_highpage_aliasing(struct page *to,
  70        struct page *from, unsigned long vaddr, struct vm_area_struct *vma)
  71{
  72        unsigned int offset = CACHE_COLOUR(vaddr);
  73        unsigned long kfrom, kto;
  74
  75        if (!test_and_set_bit(PG_dcache_clean, &from->flags))
  76                __flush_dcache_page(page_mapping_file(from), from);
  77
  78        /* FIXME: not highmem safe */
  79        discard_old_kernel_data(page_address(to));
  80
  81        /*
  82         * Now copy the page using the same cache colour as the
  83         * pages ultimate destination.
  84         */
  85        raw_spin_lock(&v6_lock);
  86
  87        kfrom = COPYPAGE_V6_FROM + (offset << PAGE_SHIFT);
  88        kto   = COPYPAGE_V6_TO + (offset << PAGE_SHIFT);
  89
  90        set_top_pte(kfrom, mk_pte(from, PAGE_KERNEL));
  91        set_top_pte(kto, mk_pte(to, PAGE_KERNEL));
  92
  93        copy_page((void *)kto, (void *)kfrom);
  94
  95        raw_spin_unlock(&v6_lock);
  96}
  97
  98/*
  99 * Clear the user page.  We need to deal with the aliasing issues,
 100 * so remap the kernel page into the same cache colour as the user
 101 * page.
 102 */
 103static void v6_clear_user_highpage_aliasing(struct page *page, unsigned long vaddr)
 104{
 105        unsigned long to = COPYPAGE_V6_TO + (CACHE_COLOUR(vaddr) << PAGE_SHIFT);
 106
 107        /* FIXME: not highmem safe */
 108        discard_old_kernel_data(page_address(page));
 109
 110        /*
 111         * Now clear the page using the same cache colour as
 112         * the pages ultimate destination.
 113         */
 114        raw_spin_lock(&v6_lock);
 115
 116        set_top_pte(to, mk_pte(page, PAGE_KERNEL));
 117        clear_page((void *)to);
 118
 119        raw_spin_unlock(&v6_lock);
 120}
 121
 122struct cpu_user_fns v6_user_fns __initdata = {
 123        .cpu_clear_user_highpage = v6_clear_user_highpage_nonaliasing,
 124        .cpu_copy_user_highpage = v6_copy_user_highpage_nonaliasing,
 125};
 126
 127static int __init v6_userpage_init(void)
 128{
 129        if (cache_is_vipt_aliasing()) {
 130                cpu_user.cpu_clear_user_highpage = v6_clear_user_highpage_aliasing;
 131                cpu_user.cpu_copy_user_highpage = v6_copy_user_highpage_aliasing;
 132        }
 133
 134        return 0;
 135}
 136
 137core_initcall(v6_userpage_init);
 138