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_clear_bit(PG_dcache_dirty, &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); 150