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