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 /*
  61  * Discard data in the kernel mapping for the new page.
  62  * FIXME: needs this MCRR to be supported.
  63  */
  64 static void discard_old_kernel_data(void *kto)
  65 {
  66         __asm__("mcrr   p15, 0, %1, %0, c6      @ 0xec401f06"
  67            :
  68            : "r" (kto),
  69              "r" ((unsigned long)kto + PAGE_SIZE - L1_CACHE_BYTES)
  70            : "cc");
  71 }
  72
  73 /*
  74  * Copy the page, taking account of the cache colour.
  75  */
  76 static void v6_copy_user_highpage_aliasing(struct page *to,
  77         struct page *from, unsigned long vaddr, struct vm_area_struct *vma)
  78 {
  79         unsigned int offset = CACHE_COLOUR(vaddr);
  80         unsigned long kfrom, kto;
  81
  82         if (!test_and_set_bit(PG_dcache_clean, &from->flags))
  83                 __flush_dcache_page(page_mapping(from), from);
  84
  85         /* FIXME: not highmem safe */
  86         discard_old_kernel_data(page_address(to));
  87
  88         /*
  89          * Now copy the page using the same cache colour as the
  90          * pages ultimate destination.
  91          */
  92         spin_lock(&v6_lock);
  93
  94         set_pte_ext(TOP_PTE(from_address) + offset, pfn_pte(page_to_pfn(from), PAGE_KERNEL), 0);
  95         set_pte_ext(TOP_PTE(to_address) + offset, pfn_pte(page_to_pfn(to), PAGE_KERNEL), 0);
  96
  97         kfrom = from_address + (offset << PAGE_SHIFT);
  98         kto   = to_address + (offset << PAGE_SHIFT);
  99
 100         flush_tlb_kernel_page(kfrom);
 101         flush_tlb_kernel_page(kto);
 102
 103         copy_page((void *)kto, (void *)kfrom);
 104
 105         spin_unlock(&v6_lock);
 106 }
 107
 108 /*
 109  * Clear the user page.  We need to deal with the aliasing issues,
 110  * so remap the kernel page into the same cache colour as the user
 111  * page.
 112  */
 113 static void v6_clear_user_highpage_aliasing(struct page *page, unsigned long vaddr)
 114 {
 115         unsigned int offset = CACHE_COLOUR(vaddr);
 116         unsigned long to = to_address + (offset << PAGE_SHIFT);
 117
 118         /* FIXME: not highmem safe */
 119         discard_old_kernel_data(page_address(page));
 120
 121         /*
 122          * Now clear the page using the same cache colour as
 123          * the pages ultimate destination.
 124          */
 125         spin_lock(&v6_lock);
 126
 127         set_pte_ext(TOP_PTE(to_address) + offset, pfn_pte(page_to_pfn(page), PAGE_KERNEL), 0);
 128         flush_tlb_kernel_page(to);
 129         clear_page((void *)to);
 130
 131         spin_unlock(&v6_lock);
 132 }
 133
 134 struct cpu_user_fns v6_user_fns __initdata = {
 135         .cpu_clear_user_highpage = v6_clear_user_highpage_nonaliasing,
 136         .cpu_copy_user_highpage = v6_copy_user_highpage_nonaliasing,
 137 };
 138
 139 static int __init v6_userpage_init(void)
 140 {
 141         if (cache_is_vipt_aliasing()) {
 142                 cpu_user.cpu_clear_user_highpage = v6_clear_user_highpage_aliasing;
 143                 cpu_user.cpu_copy_user_highpage = v6_copy_user_highpage_aliasing;
 144         }
 145
 146         return 0;
 147 }
 148
 149 core_initcall(v6_userpage_init);