arch/arm/mm/copypage-v6.c

   1 /*
   2  *  linux/arch/arm/mm/copypage-v6.c
   3  *
   4  *  Copyright (C) 2002 Deep Blue Solutions Ltd, All Rights Reserved.
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 as
   8  * published by the Free Software Foundation.
   9  */
  10 #include <linux/init.h>
  11 #include <linux/spinlock.h>
  12 #include <linux/mm.h>
  13 #include <linux/highmem.h>
  14
  15 #include <asm/pgtable.h>
  16 #include <asm/shmparam.h>
  17 #include <asm/tlbflush.h>
  18 #include <asm/cacheflush.h>
  19 #include <asm/cachetype.h>
  20
  21 #include "mm.h"
  22
  23 #if SHMLBA > 16384
  24 #error FIX ME
  25 #endif
  26
  27 static DEFINE_RAW_SPINLOCK(v6_lock);
  28
  29 /*
  30  * Copy the user page.  No aliasing to deal with so we can just
  31  * attack the kernel's existing mapping of these pages.
  32  */
  33 static void v6_copy_user_highpage_nonaliasing(struct page *to,
  34         struct page *from, unsigned long vaddr, struct vm_area_struct *vma)
  35 {
  36         void *kto, *kfrom;
  37
  38         kfrom = kmap_atomic(from);
  39         kto = kmap_atomic(to);
  40         copy_page(kto, kfrom);
  41         kunmap_atomic(kto);
  42         kunmap_atomic(kfrom);
  43 }
  44
  45 /*
  46  * Clear the user page.  No aliasing to deal with so we can just
  47  * attack the kernel's existing mapping of this page.
  48  */
  49 static void v6_clear_user_highpage_nonaliasing(struct page *page, unsigned long vaddr)
  50 {
  51         void *kaddr = kmap_atomic(page);
  52         clear_page(kaddr);
  53         kunmap_atomic(kaddr);
  54 }
  55
  56 /*
  57  * Discard data in the kernel mapping for the new page.
  58  * FIXME: needs this MCRR to be supported.
  59  */
  60 static void discard_old_kernel_data(void *kto)
  61 {
  62         __asm__("mcrr   p15, 0, %1, %0, c6      @ 0xec401f06"
  63            :
  64            : "r" (kto),
  65              "r" ((unsigned long)kto + PAGE_SIZE - 1)
  66            : "cc");
  67 }
  68
  69 /*
  70  * Copy the page, taking account of the cache colour.
  71  */
  72 static void v6_copy_user_highpage_aliasing(struct page *to,
  73         struct page *from, unsigned long vaddr, struct vm_area_struct *vma)
  74 {
  75         unsigned int offset = CACHE_COLOUR(vaddr);
  76         unsigned long kfrom, kto;
  77
  78         if (!test_and_set_bit(PG_dcache_clean, &from->flags))
  79                 __flush_dcache_page(page_mapping(from), from);
  80
  81         /* FIXME: not highmem safe */
  82         discard_old_kernel_data(page_address(to));
  83
  84         /*
  85          * Now copy the page using the same cache colour as the
  86          * pages ultimate destination.
  87          */
  88         raw_spin_lock(&v6_lock);
  89
  90         kfrom = COPYPAGE_V6_FROM + (offset << PAGE_SHIFT);
  91         kto   = COPYPAGE_V6_TO + (offset << PAGE_SHIFT);
  92
  93         set_top_pte(kfrom, mk_pte(from, PAGE_KERNEL));
  94         set_top_pte(kto, mk_pte(to, PAGE_KERNEL));
  95
  96         copy_page((void *)kto, (void *)kfrom);
  97
  98         raw_spin_unlock(&v6_lock);
  99 }
 100
 101 /*
 102  * Clear the user page.  We need to deal with the aliasing issues,
 103  * so remap the kernel page into the same cache colour as the user
 104  * page.
 105  */
 106 static void v6_clear_user_highpage_aliasing(struct page *page, unsigned long vaddr)
 107 {
 108         unsigned long to = COPYPAGE_V6_TO + (CACHE_COLOUR(vaddr) << PAGE_SHIFT);
 109
 110         /* FIXME: not highmem safe */
 111         discard_old_kernel_data(page_address(page));
 112
 113         /*
 114          * Now clear the page using the same cache colour as
 115          * the pages ultimate destination.
 116          */
 117         raw_spin_lock(&v6_lock);
 118
 119         set_top_pte(to, mk_pte(page, PAGE_KERNEL));
 120         clear_page((void *)to);
 121
 122         raw_spin_unlock(&v6_lock);
 123 }
 124
 125 struct cpu_user_fns v6_user_fns __initdata = {
 126         .cpu_clear_user_highpage = v6_clear_user_highpage_nonaliasing,
 127         .cpu_copy_user_highpage = v6_copy_user_highpage_nonaliasing,
 128 };
 129
 130 static int __init v6_userpage_init(void)
 131 {
 132         if (cache_is_vipt_aliasing()) {
 133                 cpu_user.cpu_clear_user_highpage = v6_clear_user_highpage_aliasing;
 134                 cpu_user.cpu_copy_user_highpage = v6_copy_user_highpage_aliasing;
 135         }
 136
 137         return 0;
 138 }
 139
 140 core_initcall(v6_userpage_init);