release/src-rt-6.x.4708/linux/linux-2.6.36/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         __cpuc_flush_dcache_area(kto, PAGE_SIZE);
  45         kunmap_atomic(kto, KM_USER1);
  46         kunmap_atomic(kfrom, KM_USER0);
  47 }
  48
  49 /*
  50  * Clear the user page.  No aliasing to deal with so we can just
  51  * attack the kernel's existing mapping of this page.
  52  */
  53 static void v6_clear_user_highpage_nonaliasing(struct page *page, unsigned long vaddr)
  54 {
  55         void *kaddr = kmap_atomic(page, KM_USER0);
  56         clear_page(kaddr);
  57         kunmap_atomic(kaddr, KM_USER0);
  58 }
  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 - L1_CACHE_BYTES)
  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_clear_bit(PG_dcache_dirty, &from->flags))
  79                 __flush_dcache_page(page_mapping(from), from);
  80
  81         discard_old_kernel_data(page_address(to));
  82
  83         /*
  84          * Now copy the page using the same cache colour as the
  85          * pages ultimate destination.
  86          */
  87         spin_lock(&v6_lock);
  88
  89         set_pte_ext(TOP_PTE(from_address) + offset, pfn_pte(page_to_pfn(from), PAGE_KERNEL), 0);
  90         set_pte_ext(TOP_PTE(to_address) + offset, pfn_pte(page_to_pfn(to), PAGE_KERNEL), 0);
  91
  92         kfrom = from_address + (offset << PAGE_SHIFT);
  93         kto   = to_address + (offset << PAGE_SHIFT);
  94
  95         flush_tlb_kernel_page(kfrom);
  96         flush_tlb_kernel_page(kto);
  97
  98         copy_page((void *)kto, (void *)kfrom);
  99
 100         spin_unlock(&v6_lock);
 101 }
 102
 103 /*
 104  * Clear the user page.  We need to deal with the aliasing issues,
 105  * so remap the kernel page into the same cache colour as the user
 106  * page.
 107  */
 108 static void v6_clear_user_highpage_aliasing(struct page *page, unsigned long vaddr)
 109 {
 110         unsigned int offset = CACHE_COLOUR(vaddr);
 111         unsigned long to = to_address + (offset << PAGE_SHIFT);
 112
 113         discard_old_kernel_data(page_address(page));
 114
 115         /*
 116          * Now clear the page using the same cache colour as
 117          * the pages ultimate destination.
 118          */
 119         spin_lock(&v6_lock);
 120
 121         set_pte_ext(TOP_PTE(to_address) + offset, pfn_pte(page_to_pfn(page), PAGE_KERNEL), 0);
 122         flush_tlb_kernel_page(to);
 123         clear_page((void *)to);
 124
 125         spin_unlock(&v6_lock);
 126 }
 127
 128 struct cpu_user_fns v6_user_fns __initdata = {
 129         .cpu_clear_user_highpage = v6_clear_user_highpage_nonaliasing,
 130         .cpu_copy_user_highpage = v6_copy_user_highpage_nonaliasing,
 131 };
 132
 133 static int __init v6_userpage_init(void)
 134 {
 135         if (cache_is_vipt_aliasing()) {
 136                 cpu_user.cpu_clear_user_highpage = v6_clear_user_highpage_aliasing;
 137                 cpu_user.cpu_copy_user_highpage = v6_copy_user_highpage_aliasing;
 138         }
 139
 140         return 0;
 141 }
 142
 143 core_initcall(v6_userpage_init);