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 #include <linux/pagemap.h> 12 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 struct folio *src = page_folio(from); 73 unsigned int offset = CACHE_COLOUR(vaddr); 74 unsigned long kfrom, kto; 75 76 if (!test_and_set_bit(PG_dcache_clean, &src->flags)) 77 __flush_dcache_folio(folio_flush_mapping(src), src); 78 79 /* FIXME: not highmem safe */ 80 discard_old_kernel_data(page_address(to)); 81 82 /* 83 * Now copy the page using the same cache colour as the 84 * pages ultimate destination. 85 */ 86 raw_spin_lock(&v6_lock); 87 88 kfrom = COPYPAGE_V6_FROM + (offset << PAGE_SHIFT); 89 kto = COPYPAGE_V6_TO + (offset << PAGE_SHIFT); 90 91 set_top_pte(kfrom, mk_pte(from, PAGE_KERNEL)); 92 set_top_pte(kto, mk_pte(to, PAGE_KERNEL)); 93 94 copy_page((void *)kto, (void *)kfrom); 95 96 raw_spin_unlock(&v6_lock); 97 } 98 99 /* 100 * Clear the user page. We need to deal with the aliasing issues, 101 * so remap the kernel page into the same cache colour as the user 102 * page. 103 */ 104 static void v6_clear_user_highpage_aliasing(struct page *page, unsigned long vaddr) 105 { 106 unsigned long to = COPYPAGE_V6_TO + (CACHE_COLOUR(vaddr) << PAGE_SHIFT); 107 108 /* FIXME: not highmem safe */ 109 discard_old_kernel_data(page_address(page)); 110 111 /* 112 * Now clear the page using the same cache colour as 113 * the pages ultimate destination. 114 */ 115 raw_spin_lock(&v6_lock); 116 117 set_top_pte(to, mk_pte(page, PAGE_KERNEL)); 118 clear_page((void *)to); 119 120 raw_spin_unlock(&v6_lock); 121 } 122 123 struct cpu_user_fns v6_user_fns __initdata = { 124 .cpu_clear_user_highpage = v6_clear_user_highpage_nonaliasing, 125 .cpu_copy_user_highpage = v6_copy_user_highpage_nonaliasing, 126 }; 127 128 static int __init v6_userpage_init(void) 129 { 130 if (cache_is_vipt_aliasing()) { 131 cpu_user.cpu_clear_user_highpage = v6_clear_user_highpage_aliasing; 132 cpu_user.cpu_copy_user_highpage = v6_copy_user_highpage_aliasing; 133 } 134 135 return 0; 136 } 137 138 core_initcall(v6_userpage_init); 139