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 static DEFINE_RAW_SPINLOCK(v6_lock); 28 29 /* 30 * Copy the user page. No aliasing to deal with so we can just 31 * attack the kernel's existing mapping of these pages. 32 */ 33 static void v6_copy_user_highpage_nonaliasing(struct page *to, 34 struct page *from, unsigned long vaddr, struct vm_area_struct *vma) 35 { 36 void *kto, *kfrom; 37 38 kfrom = kmap_atomic(from); 39 kto = kmap_atomic(to); 40 copy_page(kto, kfrom); 41 kunmap_atomic(kto); 42 kunmap_atomic(kfrom); 43 } 44 45 /* 46 * Clear the user page. No aliasing to deal with so we can just 47 * attack the kernel's existing mapping of this page. 48 */ 49 static void v6_clear_user_highpage_nonaliasing(struct page *page, unsigned long vaddr) 50 { 51 void *kaddr = kmap_atomic(page); 52 clear_page(kaddr); 53 kunmap_atomic(kaddr); 54 } 55 56 /* 57 * Discard data in the kernel mapping for the new page. 58 * FIXME: needs this MCRR to be supported. 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_set_bit(PG_dcache_clean, &from->flags)) 79 __flush_dcache_page(page_mapping(from), from); 80 81 /* FIXME: not highmem safe */ 82 discard_old_kernel_data(page_address(to)); 83 84 /* 85 * Now copy the page using the same cache colour as the 86 * pages ultimate destination. 87 */ 88 raw_spin_lock(&v6_lock); 89 90 kfrom = COPYPAGE_V6_FROM + (offset << PAGE_SHIFT); 91 kto = COPYPAGE_V6_TO + (offset << PAGE_SHIFT); 92 93 set_top_pte(kfrom, mk_pte(from, PAGE_KERNEL)); 94 set_top_pte(kto, mk_pte(to, PAGE_KERNEL)); 95 96 copy_page((void *)kto, (void *)kfrom); 97 98 raw_spin_unlock(&v6_lock); 99 } 100 101 /* 102 * Clear the user page. We need to deal with the aliasing issues, 103 * so remap the kernel page into the same cache colour as the user 104 * page. 105 */ 106 static void v6_clear_user_highpage_aliasing(struct page *page, unsigned long vaddr) 107 { 108 unsigned long to = COPYPAGE_V6_TO + (CACHE_COLOUR(vaddr) << PAGE_SHIFT); 109 110 /* FIXME: not highmem safe */ 111 discard_old_kernel_data(page_address(page)); 112 113 /* 114 * Now clear the page using the same cache colour as 115 * the pages ultimate destination. 116 */ 117 raw_spin_lock(&v6_lock); 118 119 set_top_pte(to, mk_pte(page, PAGE_KERNEL)); 120 clear_page((void *)to); 121 122 raw_spin_unlock(&v6_lock); 123 } 124 125 struct cpu_user_fns v6_user_fns __initdata = { 126 .cpu_clear_user_highpage = v6_clear_user_highpage_nonaliasing, 127 .cpu_copy_user_highpage = v6_copy_user_highpage_nonaliasing, 128 }; 129 130 static int __init v6_userpage_init(void) 131 { 132 if (cache_is_vipt_aliasing()) { 133 cpu_user.cpu_clear_user_highpage = v6_clear_user_highpage_aliasing; 134 cpu_user.cpu_copy_user_highpage = v6_copy_user_highpage_aliasing; 135 } 136 137 return 0; 138 } 139 140 core_initcall(v6_userpage_init); 141