arm/mm/copypage-v6.c

0001 // SPDX-License-Identifier: GPL-2.0-only
0002 /*
0003  *  linux/arch/arm/mm/copypage-v6.c
0004  *
0005  *  Copyright (C) 2002 Deep Blue Solutions Ltd, All Rights Reserved.
0006  */
0007 #include <linux/init.h>
0008 #include <linux/spinlock.h>
0009 #include <linux/mm.h>
0010 #include <linux/highmem.h>
0011 #include <linux/pagemap.h>
0012
0013 #include <asm/shmparam.h>
0014 #include <asm/tlbflush.h>
0015 #include <asm/cacheflush.h>
0016 #include <asm/cachetype.h>
0017
0018 #include "mm.h"
0019
0020 #if SHMLBA > 16384
0021 #error FIX ME
0022 #endif
0023
0024 static DEFINE_RAW_SPINLOCK(v6_lock);
0025
0026 /*
0027  * Copy the user page.  No aliasing to deal with so we can just
0028  * attack the kernel's existing mapping of these pages.
0029  */
0030 static void v6_copy_user_highpage_nonaliasing(struct page *to,
0031     struct page *from, unsigned long vaddr, struct vm_area_struct *vma)
0032 {
0033     void *kto, *kfrom;
0034
0035     kfrom = kmap_atomic(from);
0036     kto = kmap_atomic(to);
0037     copy_page(kto, kfrom);
0038     kunmap_atomic(kto);
0039     kunmap_atomic(kfrom);
0040 }
0041
0042 /*
0043  * Clear the user page.  No aliasing to deal with so we can just
0044  * attack the kernel's existing mapping of this page.
0045  */
0046 static void v6_clear_user_highpage_nonaliasing(struct page *page, unsigned long vaddr)
0047 {
0048     void *kaddr = kmap_atomic(page);
0049     clear_page(kaddr);
0050     kunmap_atomic(kaddr);
0051 }
0052
0053 /*
0054  * Discard data in the kernel mapping for the new page.
0055  * FIXME: needs this MCRR to be supported.
0056  */
0057 static void discard_old_kernel_data(void *kto)
0058 {
0059     __asm__("mcrr   p15, 0, %1, %0, c6  @ 0xec401f06"
0060        :
0061        : "r" (kto),
0062          "r" ((unsigned long)kto + PAGE_SIZE - 1)
0063        : "cc");
0064 }
0065
0066 /*
0067  * Copy the page, taking account of the cache colour.
0068  */
0069 static void v6_copy_user_highpage_aliasing(struct page *to,
0070     struct page *from, unsigned long vaddr, struct vm_area_struct *vma)
0071 {
0072     unsigned int offset = CACHE_COLOUR(vaddr);
0073     unsigned long kfrom, kto;
0074
0075     if (!test_and_set_bit(PG_dcache_clean, &from->flags))
0076         __flush_dcache_page(page_mapping_file(from), from);
0077
0078     /* FIXME: not highmem safe */
0079     discard_old_kernel_data(page_address(to));
0080
0081     /*
0082      * Now copy the page using the same cache colour as the
0083      * pages ultimate destination.
0084      */
0085     raw_spin_lock(&v6_lock);
0086
0087     kfrom = COPYPAGE_V6_FROM + (offset << PAGE_SHIFT);
0088     kto   = COPYPAGE_V6_TO + (offset << PAGE_SHIFT);
0089
0090     set_top_pte(kfrom, mk_pte(from, PAGE_KERNEL));
0091     set_top_pte(kto, mk_pte(to, PAGE_KERNEL));
0092
0093     copy_page((void *)kto, (void *)kfrom);
0094
0095     raw_spin_unlock(&v6_lock);
0096 }
0097
0098 /*
0099  * Clear the user page.  We need to deal with the aliasing issues,
0100  * so remap the kernel page into the same cache colour as the user
0101  * page.
0102  */
0103 static void v6_clear_user_highpage_aliasing(struct page *page, unsigned long vaddr)
0104 {
0105     unsigned long to = COPYPAGE_V6_TO + (CACHE_COLOUR(vaddr) << PAGE_SHIFT);
0106
0107     /* FIXME: not highmem safe */
0108     discard_old_kernel_data(page_address(page));
0109
0110     /*
0111      * Now clear the page using the same cache colour as
0112      * the pages ultimate destination.
0113      */
0114     raw_spin_lock(&v6_lock);
0115
0116     set_top_pte(to, mk_pte(page, PAGE_KERNEL));
0117     clear_page((void *)to);
0118
0119     raw_spin_unlock(&v6_lock);
0120 }
0121
0122 struct cpu_user_fns v6_user_fns __initdata = {
0123     .cpu_clear_user_highpage = v6_clear_user_highpage_nonaliasing,
0124     .cpu_copy_user_highpage = v6_copy_user_highpage_nonaliasing,
0125 };
0126
0127 static int __init v6_userpage_init(void)
0128 {
0129     if (cache_is_vipt_aliasing()) {
0130         cpu_user.cpu_clear_user_highpage = v6_clear_user_highpage_aliasing;
0131         cpu_user.cpu_copy_user_highpage = v6_copy_user_highpage_aliasing;
0132     }
0133
0134     return 0;
0135 }
0136
0137 core_initcall(v6_userpage_init);