copypage-v6.c
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/*
* linux/arch/arm/mm/copypage-v6.c
*
* Copyright (C) 2002 Deep Blue Solutions Ltd, All Rights Reserved.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/init.h>
#include <linux/spinlock.h>
#include <linux/mm.h>
#include <linux/highmem.h>
#include <asm/pgtable.h>
#include <asm/shmparam.h>
#include <asm/tlbflush.h>
#include <asm/cacheflush.h>
#include <asm/cachetype.h>
#include "mm.h"
#if SHMLBA > 16384
#error FIX ME
#endif
static DEFINE_RAW_SPINLOCK(v6_lock);
/*
* Copy the user page. No aliasing to deal with so we can just
* attack the kernel's existing mapping of these pages.
*/
static void v6_copy_user_highpage_nonaliasing(struct page *to,
struct page *from, unsigned long vaddr, struct vm_area_struct *vma)
{
void *kto, *kfrom;
kfrom = kmap_atomic(from);
kto = kmap_atomic(to);
copy_page(kto, kfrom);
kunmap_atomic(kto);
kunmap_atomic(kfrom);
}
/*
* Clear the user page. No aliasing to deal with so we can just
* attack the kernel's existing mapping of this page.
*/
static void v6_clear_user_highpage_nonaliasing(struct page *page, unsigned long vaddr)
{
void *kaddr = kmap_atomic(page);
clear_page(kaddr);
kunmap_atomic(kaddr);
}
/*
* Discard data in the kernel mapping for the new page.
* FIXME: needs this MCRR to be supported.
*/
static void discard_old_kernel_data(void *kto)
{
__asm__("mcrr p15, 0, %1, %0, c6 @ 0xec401f06"
:
: "r" (kto),
"r" ((unsigned long)kto + PAGE_SIZE - L1_CACHE_BYTES)
: "cc");
}
/*
* Copy the page, taking account of the cache colour.
*/
static void v6_copy_user_highpage_aliasing(struct page *to,
struct page *from, unsigned long vaddr, struct vm_area_struct *vma)
{
unsigned int offset = CACHE_COLOUR(vaddr);
unsigned long kfrom, kto;
if (!test_and_set_bit(PG_dcache_clean, &from->flags))
__flush_dcache_page(page_mapping(from), from);
/* FIXME: not highmem safe */
discard_old_kernel_data(page_address(to));
/*
* Now copy the page using the same cache colour as the
* pages ultimate destination.
*/
raw_spin_lock(&v6_lock);
kfrom = COPYPAGE_V6_FROM + (offset << PAGE_SHIFT);
kto = COPYPAGE_V6_TO + (offset << PAGE_SHIFT);
set_top_pte(kfrom, mk_pte(from, PAGE_KERNEL));
set_top_pte(kto, mk_pte(to, PAGE_KERNEL));
copy_page((void *)kto, (void *)kfrom);
raw_spin_unlock(&v6_lock);
}
/*
* Clear the user page. We need to deal with the aliasing issues,
* so remap the kernel page into the same cache colour as the user
* page.
*/
static void v6_clear_user_highpage_aliasing(struct page *page, unsigned long vaddr)
{
unsigned long to = COPYPAGE_V6_TO + (CACHE_COLOUR(vaddr) << PAGE_SHIFT);
/* FIXME: not highmem safe */
discard_old_kernel_data(page_address(page));
/*
* Now clear the page using the same cache colour as
* the pages ultimate destination.
*/
raw_spin_lock(&v6_lock);
set_top_pte(to, mk_pte(page, PAGE_KERNEL));
clear_page((void *)to);
raw_spin_unlock(&v6_lock);
}
struct cpu_user_fns v6_user_fns __initdata = {
.cpu_clear_user_highpage = v6_clear_user_highpage_nonaliasing,
.cpu_copy_user_highpage = v6_copy_user_highpage_nonaliasing,
};
static int __init v6_userpage_init(void)
{
if (cache_is_vipt_aliasing()) {
cpu_user.cpu_clear_user_highpage = v6_clear_user_highpage_aliasing;
cpu_user.cpu_copy_user_highpage = v6_copy_user_highpage_aliasing;
}
return 0;
}
core_initcall(v6_userpage_init);