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
  14 #include <asm/page.h>
  15 #include <asm/pgtable.h>
  16 #include <asm/shmparam.h>
  17 #include <asm/tlbflush.h>
  18 #include <asm/cacheflush.h>
  19
  20 #include "mm.h"
  21
  22 #if SHMLBA > 16384
  23 #error FIX ME
  24 #endif
  25
  26 #define from_address    (0xffff8000)
  27 #define to_address      (0xffffc000)
  28
  29 static DEFINE_SPINLOCK(v6_lock);
  30
  31 /*
  32  * Copy the user page.  No aliasing to deal with so we can just
  33  * attack the kernel's existing mapping of these pages.
  34  */
  35 static void v6_copy_user_page_nonaliasing(void *kto, const void *kfrom, unsigned long vaddr)
  36 {
  37         copy_page(kto, kfrom);
  38 }
  39
  40 /*
  41  * Clear the user page.  No aliasing to deal with so we can just
  42  * attack the kernel's existing mapping of this page.
  43  */
  44 static void v6_clear_user_page_nonaliasing(void *kaddr, unsigned long vaddr)
  45 {
  46         clear_page(kaddr);
  47 }
  48
  49 /*
  50  * Copy the page, taking account of the cache colour.
  51  */
  52 static void v6_copy_user_page_aliasing(void *kto, const void *kfrom, unsigned long vaddr)
  53 {
  54         unsigned int offset = CACHE_COLOUR(vaddr);
  55         unsigned long from, to;
  56         struct page *page = virt_to_page(kfrom);
  57
  58         if (test_and_clear_bit(PG_dcache_dirty, &page->flags))
  59                 __flush_dcache_page(page_mapping(page), page);
  60
  61         /*
  62          * Discard data in the kernel mapping for the new page.
  63          * FIXME: needs this MCRR to be supported.
  64          */
  65         __asm__("mcrr   p15, 0, %1, %0, c6      @ 0xec401f06"
  66            :
  67            : "r" (kto),
  68              "r" ((unsigned long)kto + PAGE_SIZE - L1_CACHE_BYTES)
  69            : "cc");
  70
  71         /*
  72          * Now copy the page using the same cache colour as the
  73          * pages ultimate destination.
  74          */
  75         spin_lock(&v6_lock);
  76
  77         set_pte_ext(TOP_PTE(from_address) + offset, pfn_pte(__pa(kfrom) >> PAGE_SHIFT, PAGE_KERNEL), 0);
  78         set_pte_ext(TOP_PTE(to_address) + offset, pfn_pte(__pa(kto) >> PAGE_SHIFT, PAGE_KERNEL), 0);
  79
  80         from = from_address + (offset << PAGE_SHIFT);
  81         to   = to_address + (offset << PAGE_SHIFT);
  82
  83         flush_tlb_kernel_page(from);
  84         flush_tlb_kernel_page(to);
  85
  86         copy_page((void *)to, (void *)from);
  87
  88         spin_unlock(&v6_lock);
  89 }
  90
  91 /*
  92  * Clear the user page.  We need to deal with the aliasing issues,
  93  * so remap the kernel page into the same cache colour as the user
  94  * page.
  95  */
  96 static void v6_clear_user_page_aliasing(void *kaddr, unsigned long vaddr)
  97 {
  98         unsigned int offset = CACHE_COLOUR(vaddr);
  99         unsigned long to = to_address + (offset << PAGE_SHIFT);
 100
 101         /*
 102          * Discard data in the kernel mapping for the new page
 103          * FIXME: needs this MCRR to be supported.
 104          */
 105         __asm__("mcrr   p15, 0, %1, %0, c6      @ 0xec401f06"
 106            :
 107            : "r" (kaddr),
 108              "r" ((unsigned long)kaddr + PAGE_SIZE - L1_CACHE_BYTES)
 109            : "cc");
 110
 111         /*
 112          * Now clear the page using the same cache colour as
 113          * the pages ultimate destination.
 114          */
 115         spin_lock(&v6_lock);
 116
 117         set_pte_ext(TOP_PTE(to_address) + offset, pfn_pte(__pa(kaddr) >> PAGE_SHIFT, PAGE_KERNEL), 0);
 118         flush_tlb_kernel_page(to);
 119         clear_page((void *)to);
 120
 121         spin_unlock(&v6_lock);
 122 }
 123
 124 struct cpu_user_fns v6_user_fns __initdata = {
 125         .cpu_clear_user_page    = v6_clear_user_page_nonaliasing,
 126         .cpu_copy_user_page     = v6_copy_user_page_nonaliasing,
 127 };
 128
 129 static int __init v6_userpage_init(void)
 130 {
 131         if (cache_is_vipt_aliasing()) {
 132                 cpu_user.cpu_clear_user_page = v6_clear_user_page_aliasing;
 133                 cpu_user.cpu_copy_user_page = v6_copy_user_page_aliasing;
 134         }
 135
 136         return 0;
 137 }
 138
 139 core_initcall(v6_userpage_init);