original_kernel/arch/arm/mm/copypage-v3.c

/*
 *  linux/arch/arm/mm/copypage-v3.c
 *
 *  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.
 */
#include <linux/init.h>
#include <linux/highmem.h>

/*
 * ARMv3 optimised copy_user_highpage
 *
 * FIXME: do we need to handle cache stuff...
 */
static void __attribute__((naked))
v3_copy_user_page(void *kto, const void *kfrom)
{
	asm("\n\
	stmfd	sp!, {r4, lr}			@	2\n\
	mov	r2, %2				@	1\n\
	ldmia	%0!, {r3, r4, ip, lr}		@	4+1\n\
1:	stmia	%1!, {r3, r4, ip, lr}		@	4\n\
	ldmia	%0!, {r3, r4, ip, lr}		@	4+1\n\
	stmia	%1!, {r3, r4, ip, lr}		@	4\n\
	ldmia	%0!, {r3, r4, ip, lr}		@	4+1\n\
	stmia	%1!, {r3, r4, ip, lr}		@	4\n\
	ldmia	%0!, {r3, r4, ip, lr}		@	4\n\
	subs	r2, r2, #1			@	1\n\
	stmia	%1!, {r3, r4, ip, lr}		@	4\n\
	ldmneia	%0!, {r3, r4, ip, lr}		@	4\n\
	bne	1b				@	1\n\
	ldmfd	sp!, {r4, pc}			@	3"
	:
	: "r" (kfrom), "r" (kto), "I" (PAGE_SIZE / 64));
}

void v3_copy_user_highpage(struct page *to, struct page *from,
	unsigned long vaddr)
{
	void *kto, *kfrom;

	kto = kmap_atomic(to, KM_USER0);
	kfrom = kmap_atomic(from, KM_USER1);
	v3_copy_user_page(kto, kfrom);
	kunmap_atomic(kfrom, KM_USER1);
	kunmap_atomic(kto, KM_USER0);
}

/*
 * ARMv3 optimised clear_user_page
 *
 * FIXME: do we need to handle cache stuff...
 */
void __attribute__((naked)) v3_clear_user_page(void *kaddr, unsigned long vaddr)
{
	asm("\n\
	str	lr, [sp, #-4]!\n\
	mov	r1, %1				@ 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\
	ldr	pc, [sp], #4"
	:
	: "r" (kaddr), "I" (PAGE_SIZE / 64));
}

struct cpu_user_fns v3_user_fns __initdata = {
	.cpu_clear_user_page	= v3_clear_user_page,
	.cpu_copy_user_highpage	= v3_copy_user_highpage,
};