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