root/arch/arm/mm/copypage-v6.c

DEFINITIONS

1. v6_copy_user_highpage_nonaliasing
2. v6_clear_user_highpage_nonaliasing
3. discard_old_kernel_data
4. v6_copy_user_highpage_aliasing
5. v6_clear_user_highpage_aliasing
6. v6_userpage_init

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  *  linux/arch/arm/mm/copypage-v6.c
   4  *
   5  *  Copyright (C) 2002 Deep Blue Solutions Ltd, All Rights Reserved.
   6  */
   7 #include <linux/init.h>
   8 #include <linux/spinlock.h>
   9 #include <linux/mm.h>
  10 #include <linux/highmem.h>
  11 
  12 #include <asm/pgtable.h>
  13 #include <asm/shmparam.h>
  14 #include <asm/tlbflush.h>
  15 #include <asm/cacheflush.h>
  16 #include <asm/cachetype.h>
  17 
  18 #include "mm.h"
  19 
  20 #if SHMLBA > 16384
  21 #error FIX ME
  22 #endif
  23 
  24 static DEFINE_RAW_SPINLOCK(v6_lock);
  25 
  26 /*
  27  * Copy the user page.  No aliasing to deal with so we can just
  28  * attack the kernel's existing mapping of these pages.
  29  */
  30 static void v6_copy_user_highpage_nonaliasing(struct page *to,
  31         struct page *from, unsigned long vaddr, struct vm_area_struct *vma)
  32 {
  33         void *kto, *kfrom;
  34 
  35         kfrom = kmap_atomic(from);
  36         kto = kmap_atomic(to);
  37         copy_page(kto, kfrom);
  38         kunmap_atomic(kto);
  39         kunmap_atomic(kfrom);
  40 }
  41 
  42 /*
  43  * Clear the user page.  No aliasing to deal with so we can just
  44  * attack the kernel's existing mapping of this page.
  45  */
  46 static void v6_clear_user_highpage_nonaliasing(struct page *page, unsigned long vaddr)
  47 {
  48         void *kaddr = kmap_atomic(page);
  49         clear_page(kaddr);
  50         kunmap_atomic(kaddr);
  51 }
  52 
  53 /*
  54  * Discard data in the kernel mapping for the new page.
  55  * FIXME: needs this MCRR to be supported.
  56  */
  57 static void discard_old_kernel_data(void *kto)
  58 {
  59         __asm__("mcrr   p15, 0, %1, %0, c6      @ 0xec401f06"
  60            :
  61            : "r" (kto),
  62              "r" ((unsigned long)kto + PAGE_SIZE - 1)
  63            : "cc");
  64 }
  65 
  66 /*
  67  * Copy the page, taking account of the cache colour.
  68  */
  69 static void v6_copy_user_highpage_aliasing(struct page *to,
  70         struct page *from, unsigned long vaddr, struct vm_area_struct *vma)
  71 {
  72         unsigned int offset = CACHE_COLOUR(vaddr);
  73         unsigned long kfrom, kto;
  74 
  75         if (!test_and_set_bit(PG_dcache_clean, &from->flags))
  76                 __flush_dcache_page(page_mapping_file(from), from);
  77 
  78         /* FIXME: not highmem safe */
  79         discard_old_kernel_data(page_address(to));
  80 
  81         /*
  82          * Now copy the page using the same cache colour as the
  83          * pages ultimate destination.
  84          */
  85         raw_spin_lock(&v6_lock);
  86 
  87         kfrom = COPYPAGE_V6_FROM + (offset << PAGE_SHIFT);
  88         kto   = COPYPAGE_V6_TO + (offset << PAGE_SHIFT);
  89 
  90         set_top_pte(kfrom, mk_pte(from, PAGE_KERNEL));
  91         set_top_pte(kto, mk_pte(to, PAGE_KERNEL));
  92 
  93         copy_page((void *)kto, (void *)kfrom);
  94 
  95         raw_spin_unlock(&v6_lock);
  96 }
  97 
  98 /*
  99  * Clear the user page.  We need to deal with the aliasing issues,
 100  * so remap the kernel page into the same cache colour as the user
 101  * page.
 102  */
 103 static void v6_clear_user_highpage_aliasing(struct page *page, unsigned long vaddr)
 104 {
 105         unsigned long to = COPYPAGE_V6_TO + (CACHE_COLOUR(vaddr) << PAGE_SHIFT);
 106 
 107         /* FIXME: not highmem safe */
 108         discard_old_kernel_data(page_address(page));
 109 
 110         /*
 111          * Now clear the page using the same cache colour as
 112          * the pages ultimate destination.
 113          */
 114         raw_spin_lock(&v6_lock);
 115 
 116         set_top_pte(to, mk_pte(page, PAGE_KERNEL));
 117         clear_page((void *)to);
 118 
 119         raw_spin_unlock(&v6_lock);
 120 }
 121 
 122 struct cpu_user_fns v6_user_fns __initdata = {
 123         .cpu_clear_user_highpage = v6_clear_user_highpage_nonaliasing,
 124         .cpu_copy_user_highpage = v6_copy_user_highpage_nonaliasing,
 125 };
 126 
 127 static int __init v6_userpage_init(void)
 128 {
 129         if (cache_is_vipt_aliasing()) {
 130                 cpu_user.cpu_clear_user_highpage = v6_clear_user_highpage_aliasing;
 131                 cpu_user.cpu_copy_user_highpage = v6_copy_user_highpage_aliasing;
 132         }
 133 
 134         return 0;
 135 }
 136 
 137 core_initcall(v6_userpage_init);