copypage-v4wt.c
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/*
* linux/arch/arm/mm/copypage-v4wt.S
*
* Copyright (C) 1995-1999 Russell King
*
* 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.
*
* This is for CPUs with a writethrough cache and 'flush ID cache' is
* the only supported cache operation.
*/
#include <linux/init.h>
#include <linux/highmem.h>
/*
* ARMv4 optimised copy_user_highpage
*
* Since we have writethrough caches, we don't have to worry about
* dirty data in the cache. However, we do have to ensure that
* subsequent reads are up to date.
*/
static void __naked
v4wt_copy_user_page(void *kto, const void *kfrom)
{
asm("\
stmfd sp!, {r4, lr} @ 2\n\
mov r2, %2 @ 1\n\
ldmia r1!, {r3, r4, ip, lr} @ 4\n\
1: stmia r0!, {r3, r4, ip, lr} @ 4\n\
ldmia r1!, {r3, r4, ip, lr} @ 4+1\n\
stmia r0!, {r3, r4, ip, lr} @ 4\n\
ldmia r1!, {r3, r4, ip, lr} @ 4\n\
stmia r0!, {r3, r4, ip, lr} @ 4\n\
ldmia r1!, {r3, r4, ip, lr} @ 4\n\
subs r2, r2, #1 @ 1\n\
stmia r0!, {r3, r4, ip, lr} @ 4\n\
ldmneia r1!, {r3, r4, ip, lr} @ 4\n\
bne 1b @ 1\n\
mcr p15, 0, r2, c7, c7, 0 @ flush ID cache\n\
ldmfd sp!, {r4, pc} @ 3"
:
: "r" (kto), "r" (kfrom), "I" (PAGE_SIZE / 64));
}
void v4wt_copy_user_highpage(struct page *to, struct page *from,
unsigned long vaddr, struct vm_area_struct *vma)
{
void *kto, *kfrom;
kto = kmap_atomic(to);
kfrom = kmap_atomic(from);
v4wt_copy_user_page(kto, kfrom);
kunmap_atomic(kfrom);
kunmap_atomic(kto);
}
/*
* ARMv4 optimised clear_user_page
*
* Same story as above.
*/
void v4wt_clear_user_highpage(struct page *page, unsigned long vaddr)
{
void *ptr, *kaddr = kmap_atomic(page);
asm volatile("\
mov r1, %2 @ 1\n\
mov r2, #0 @ 1\n\
mov r3, #0 @ 1\n\
mov ip, #0 @ 1\n\
mov lr, #0 @ 1\n\
1: stmia %0!, {r2, r3, ip, lr} @ 4\n\
stmia %0!, {r2, r3, ip, lr} @ 4\n\
stmia %0!, {r2, r3, ip, lr} @ 4\n\
stmia %0!, {r2, r3, ip, lr} @ 4\n\
subs r1, r1, #1 @ 1\n\
bne 1b @ 1\n\
mcr p15, 0, r2, c7, c7, 0 @ flush ID cache"
: "=r" (ptr)
: "0" (kaddr), "I" (PAGE_SIZE / 64)
: "r1", "r2", "r3", "ip", "lr");
kunmap_atomic(kaddr);
}
struct cpu_user_fns v4wt_user_fns __initdata = {
.cpu_clear_user_highpage = v4wt_clear_user_highpage,
.cpu_copy_user_highpage = v4wt_copy_user_highpage,
};