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, struct vm_area_struct *vma)
  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 #ifdef CONFIG_HIGHMEM
  45         /*
  46          * kmap_atomic() doesn't set the page virtual address, and
  47          * kunmap_atomic() takes care of cache flushing already.
  48          */
  49         if (page_address(to) != NULL)
  50 #endif
  51                 __cpuc_flush_dcache_area(kto, PAGE_SIZE);
  52         kunmap_atomic(kto, KM_USER1);
  53         kunmap_atomic(kfrom, KM_USER0);
  54 }
  55
  56 /*
  57  * Clear the user page.  No aliasing to deal with so we can just
  58  * attack the kernel's existing mapping of this page.
  59  */
  60 static void v6_clear_user_highpage_nonaliasing(struct page *page, unsigned long vaddr)
  61 {
  62         void *kaddr = kmap_atomic(page, KM_USER0);
  63         clear_page(kaddr);
  64         kunmap_atomic(kaddr, KM_USER0);
  65 }
  66
  67 /*
  68  * Discard data in the kernel mapping for the new page.
  69  * FIXME: needs this MCRR to be supported.
  70  */
  71 static void discard_old_kernel_data(void *kto)
  72 {
  73         __asm__("mcrr   p15, 0, %1, %0, c6      @ 0xec401f06"
  74            :
  75            : "r" (kto),
  76              "r" ((unsigned long)kto + PAGE_SIZE - L1_CACHE_BYTES)
  77            : "cc");
  78 }
  79
  80 /*
  81  * Copy the page, taking account of the cache colour.
  82  */
  83 static void v6_copy_user_highpage_aliasing(struct page *to,
  84         struct page *from, unsigned long vaddr, struct vm_area_struct *vma)
  85 {
  86         unsigned int offset = CACHE_COLOUR(vaddr);
  87         unsigned long kfrom, kto;
  88
  89         if (test_and_clear_bit(PG_dcache_dirty, &from->flags))
  90                 __flush_dcache_page(page_mapping(from), from);
  91
  92         /* FIXME: not highmem safe */
  93         discard_old_kernel_data(page_address(to));
  94
  95         /*
  96          * Now copy the page using the same cache colour as the
  97          * pages ultimate destination.
  98          */
  99         spin_lock(&v6_lock);
 100
 101         set_pte_ext(TOP_PTE(from_address) + offset, pfn_pte(page_to_pfn(from), PAGE_KERNEL), 0);
 102         set_pte_ext(TOP_PTE(to_address) + offset, pfn_pte(page_to_pfn(to), PAGE_KERNEL), 0);
 103
 104         kfrom = from_address + (offset << PAGE_SHIFT);
 105         kto   = to_address + (offset << PAGE_SHIFT);
 106
 107         flush_tlb_kernel_page(kfrom);
 108         flush_tlb_kernel_page(kto);
 109
 110         copy_page((void *)kto, (void *)kfrom);
 111
 112         spin_unlock(&v6_lock);
 113 }
 114
 115 /*
 116  * Clear the user page.  We need to deal with the aliasing issues,
 117  * so remap the kernel page into the same cache colour as the user
 118  * page.
 119  */
 120 static void v6_clear_user_highpage_aliasing(struct page *page, unsigned long vaddr)
 121 {
 122         unsigned int offset = CACHE_COLOUR(vaddr);
 123         unsigned long to = to_address + (offset << PAGE_SHIFT);
 124
 125         /* FIXME: not highmem safe */
 126         discard_old_kernel_data(page_address(page));
 127
 128         /*
 129          * Now clear the page using the same cache colour as
 130          * the pages ultimate destination.
 131          */
 132         spin_lock(&v6_lock);
 133
 134         set_pte_ext(TOP_PTE(to_address) + offset, pfn_pte(page_to_pfn(page), PAGE_KERNEL), 0);
 135         flush_tlb_kernel_page(to);
 136         clear_page((void *)to);
 137
 138         spin_unlock(&v6_lock);
 139 }
 140
 141 struct cpu_user_fns v6_user_fns __initdata = {
 142         .cpu_clear_user_highpage = v6_clear_user_highpage_nonaliasing,
 143         .cpu_copy_user_highpage = v6_copy_user_highpage_nonaliasing,
 144 };
 145
 146 static int __init v6_userpage_init(void)
 147 {
 148         if (cache_is_vipt_aliasing()) {
 149                 cpu_user.cpu_clear_user_highpage = v6_clear_user_highpage_aliasing;
 150                 cpu_user.cpu_copy_user_highpage = v6_copy_user_highpage_aliasing;
 151         }
 152
 153         return 0;
 154 }
 155
 156 core_initcall(v6_userpage_init);