063b0a4207
We used to override the copy_user_page() function. However, this is not only inefficient, it also causes additional complexity for highmem support, since we convert from a struct page to a kernel direct mapped address and back to a struct page again. Moreover, with highmem support, we end up pointlessly setting up kmap entries for pages which we're going to remap. So, push the kmapping down into the copypage implementation files where it's required. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
154 lines
3.8 KiB
C
154 lines
3.8 KiB
C
/*
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* linux/arch/arm/mm/copypage-v6.c
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*
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* Copyright (C) 2002 Deep Blue Solutions Ltd, All Rights Reserved.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#include <linux/init.h>
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#include <linux/spinlock.h>
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#include <linux/mm.h>
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#include <linux/highmem.h>
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#include <asm/pgtable.h>
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#include <asm/shmparam.h>
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#include <asm/tlbflush.h>
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#include <asm/cacheflush.h>
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#include <asm/cachetype.h>
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#include "mm.h"
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#if SHMLBA > 16384
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#error FIX ME
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#endif
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#define from_address (0xffff8000)
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#define to_address (0xffffc000)
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static DEFINE_SPINLOCK(v6_lock);
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/*
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* Copy the user page. No aliasing to deal with so we can just
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* attack the kernel's existing mapping of these pages.
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*/
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static void v6_copy_user_highpage_nonaliasing(struct page *to,
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struct page *from, unsigned long vaddr)
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{
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void *kto, *kfrom;
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kfrom = kmap_atomic(from, KM_USER0);
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kto = kmap_atomic(to, KM_USER1);
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copy_page(kto, kfrom);
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kunmap_atomic(kto, KM_USER1);
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kunmap_atomic(kfrom, KM_USER0);
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}
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/*
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* Clear the user page. No aliasing to deal with so we can just
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* attack the kernel's existing mapping of this page.
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*/
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static void v6_clear_user_page_nonaliasing(void *kaddr, unsigned long vaddr)
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{
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clear_page(kaddr);
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}
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/*
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* Discard data in the kernel mapping for the new page.
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* FIXME: needs this MCRR to be supported.
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*/
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static void discard_old_kernel_data(void *kto)
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{
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__asm__("mcrr p15, 0, %1, %0, c6 @ 0xec401f06"
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:
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: "r" (kto),
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"r" ((unsigned long)kto + PAGE_SIZE - L1_CACHE_BYTES)
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: "cc");
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}
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/*
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* Copy the page, taking account of the cache colour.
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*/
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static void v6_copy_user_highpage_aliasing(struct page *to,
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struct page *from, unsigned long vaddr)
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{
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unsigned int offset = CACHE_COLOUR(vaddr);
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unsigned long kfrom, kto;
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if (test_and_clear_bit(PG_dcache_dirty, &from->flags))
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__flush_dcache_page(page_mapping(from), from);
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/* FIXME: not highmem safe */
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discard_old_kernel_data(page_address(to));
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/*
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* Now copy the page using the same cache colour as the
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* pages ultimate destination.
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*/
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spin_lock(&v6_lock);
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set_pte_ext(TOP_PTE(from_address) + offset, pfn_pte(page_to_pfn(from), PAGE_KERNEL), 0);
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set_pte_ext(TOP_PTE(to_address) + offset, pfn_pte(page_to_pfn(to), PAGE_KERNEL), 0);
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kfrom = from_address + (offset << PAGE_SHIFT);
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kto = to_address + (offset << PAGE_SHIFT);
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flush_tlb_kernel_page(kfrom);
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flush_tlb_kernel_page(kto);
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copy_page((void *)kto, (void *)kfrom);
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spin_unlock(&v6_lock);
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}
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/*
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* Clear the user page. We need to deal with the aliasing issues,
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* so remap the kernel page into the same cache colour as the user
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* page.
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*/
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static void v6_clear_user_page_aliasing(void *kaddr, unsigned long vaddr)
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{
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unsigned int offset = CACHE_COLOUR(vaddr);
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unsigned long to = to_address + (offset << PAGE_SHIFT);
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/*
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* Discard data in the kernel mapping for the new page
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* FIXME: needs this MCRR to be supported.
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*/
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__asm__("mcrr p15, 0, %1, %0, c6 @ 0xec401f06"
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:
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: "r" (kaddr),
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"r" ((unsigned long)kaddr + PAGE_SIZE - L1_CACHE_BYTES)
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: "cc");
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/*
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* Now clear the page using the same cache colour as
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* the pages ultimate destination.
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*/
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spin_lock(&v6_lock);
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set_pte_ext(TOP_PTE(to_address) + offset, pfn_pte(__pa(kaddr) >> PAGE_SHIFT, PAGE_KERNEL), 0);
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flush_tlb_kernel_page(to);
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clear_page((void *)to);
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spin_unlock(&v6_lock);
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}
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struct cpu_user_fns v6_user_fns __initdata = {
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.cpu_clear_user_page = v6_clear_user_page_nonaliasing,
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.cpu_copy_user_highpage = v6_copy_user_highpage_nonaliasing,
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};
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static int __init v6_userpage_init(void)
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{
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if (cache_is_vipt_aliasing()) {
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cpu_user.cpu_clear_user_page = v6_clear_user_page_aliasing;
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cpu_user.cpu_copy_user_highpage = v6_copy_user_highpage_aliasing;
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}
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return 0;
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}
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core_initcall(v6_userpage_init);
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