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 #define from_address    (0xffff8000)
  28 #define to_address      (0xffffc000)
  29
  30 static DEFINE_SPINLOCK(v6_lock);
  31
  32 /*
  33  * Copy the user page.  No aliasing to deal with so we can just
  34  * attack the kernel's existing mapping of these pages.
  35  */
  36 static void v6_copy_user_highpage_nonaliasing(struct page *to,
  37         struct page *from, unsigned long vaddr)
  38 {
  39         void *kto, *kfrom;
  40
  41         kfrom = kmap_atomic(from, KM_USER0);
  42         kto = kmap_atomic(to, KM_USER1);
  43         copy_page(kto, kfrom);
  44         kunmap_atomic(kto, KM_USER1);
  45         kunmap_atomic(kfrom, KM_USER0);
  46 }
  47
  48 /*
  49  * Clear the user page.  No aliasing to deal with so we can just
  50  * attack the kernel's existing mapping of this page.
  51  */
  52 static void v6_clear_user_highpage_nonaliasing(struct page *page, unsigned long vaddr)
  53 {
  54         void *kaddr = kmap_atomic(page, KM_USER0);
  55         clear_page(kaddr);
  56         kunmap_atomic(kaddr, KM_USER0);
  57 }
  58
  59 /*
  60  * Discard data in the kernel mapping for the new page.
  61  * FIXME: needs this MCRR to be supported.
  62  */
  63 static void discard_old_kernel_data(void *kto)
  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 /*
  73  * Copy the page, taking account of the cache colour.
  74  */
  75 static void v6_copy_user_highpage_aliasing(struct page *to,
  76         struct page *from, unsigned long vaddr)
  77 {
  78         unsigned int offset = CACHE_COLOUR(vaddr);
  79         unsigned long kfrom, kto;
  80
  81         if (test_and_clear_bit(PG_dcache_dirty, &from->flags))
  82                 __flush_dcache_page(page_mapping(from), from);
  83
  84         /* FIXME: not highmem safe */
  85         discard_old_kernel_data(page_address(to));
  86
  87         /*
  88          * Now copy the page using the same cache colour as the
  89          * pages ultimate destination.
  90          */
  91         spin_lock(&v6_lock);
  92
  93         set_pte_ext(TOP_PTE(from_address) + offset, pfn_pte(page_to_pfn(from), PAGE_KERNEL), 0);
  94         set_pte_ext(TOP_PTE(to_address) + offset, pfn_pte(page_to_pfn(to), PAGE_KERNEL), 0);
  95
  96         kfrom = from_address + (offset << PAGE_SHIFT);
  97         kto   = to_address + (offset << PAGE_SHIFT);
  98
  99         flush_tlb_kernel_page(kfrom);
 100         flush_tlb_kernel_page(kto);
 101
 102         copy_page((void *)kto, (void *)kfrom);
 103
 104         spin_unlock(&v6_lock);
 105 }
 106
 107 /*
 108  * Clear the user page.  We need to deal with the aliasing issues,
 109  * so remap the kernel page into the same cache colour as the user
 110  * page.
 111  */
 112 static void v6_clear_user_highpage_aliasing(struct page *page, unsigned long vaddr)
 113 {
 114         unsigned int offset = CACHE_COLOUR(vaddr);
 115         unsigned long to = to_address + (offset << PAGE_SHIFT);
 116
 117         /* FIXME: not highmem safe */
 118         discard_old_kernel_data(page_address(page));
 119
 120         /*
 121          * Now clear the page using the same cache colour as
 122          * the pages ultimate destination.
 123          */
 124         spin_lock(&v6_lock);
 125
 126         set_pte_ext(TOP_PTE(to_address) + offset, pfn_pte(page_to_pfn(page), PAGE_KERNEL), 0);
 127         flush_tlb_kernel_page(to);
 128         clear_page((void *)to);
 129
 130         spin_unlock(&v6_lock);
 131 }
 132
 133 struct cpu_user_fns v6_user_fns __initdata = {
 134         .cpu_clear_user_highpage = v6_clear_user_highpage_nonaliasing,
 135         .cpu_copy_user_highpage = v6_copy_user_highpage_nonaliasing,
 136 };
 137
 138 static int __init v6_userpage_init(void)
 139 {
 140         if (cache_is_vipt_aliasing()) {
 141                 cpu_user.cpu_clear_user_highpage = v6_clear_user_highpage_aliasing;
 142                 cpu_user.cpu_copy_user_highpage = v6_copy_user_highpage_aliasing;
 143         }
 144
 145         return 0;
 146 }
 147
 148 core_initcall(v6_userpage_init);