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/*
* This file contains miscellaneous low-level functions.
* Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
*
* Largely rewritten by Cort Dougan (cort@cs.nmt.edu)
* and Paul Mackerras.
*
* A couple of functions stolen from arch/ppc/kernel/misc.S for UML
* by Chris Emerson.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*
*/
#include <linux/config.h>
#include <asm/processor.h>
#include "ppc_asm.h"
#if defined(CONFIG_4xx) || defined(CONFIG_8xx)
#define CACHE_LINE_SIZE 16
#define LG_CACHE_LINE_SIZE 4
#define MAX_COPY_PREFETCH 1
#else
#define CACHE_LINE_SIZE 32
#define LG_CACHE_LINE_SIZE 5
#define MAX_COPY_PREFETCH 4
#endif /* CONFIG_4xx || CONFIG_8xx */
.text
/*
* Clear a page using the dcbz instruction, which doesn't cause any
* memory traffic (except to write out any cache lines which get
* displaced). This only works on cacheable memory.
*/
_GLOBAL(clear_page)
li r0,4096/CACHE_LINE_SIZE
mtctr r0
#ifdef CONFIG_8xx
li r4, 0
1: stw r4, 0(r3)
stw r4, 4(r3)
stw r4, 8(r3)
stw r4, 12(r3)
#else
1: dcbz 0,r3
#endif
addi r3,r3,CACHE_LINE_SIZE
bdnz 1b
blr
/*
* Copy a whole page. We use the dcbz instruction on the destination
* to reduce memory traffic (it eliminates the unnecessary reads of
* the destination into cache). This requires that the destination
* is cacheable.
*/
#define COPY_16_BYTES \
lwz r6,4(r4); \
lwz r7,8(r4); \
lwz r8,12(r4); \
lwzu r9,16(r4); \
stw r6,4(r3); \
stw r7,8(r3); \
stw r8,12(r3); \
stwu r9,16(r3)
_GLOBAL(copy_page)
addi r3,r3,-4
addi r4,r4,-4
li r5,4
#ifndef CONFIG_8xx
#if MAX_COPY_PREFETCH > 1
li r0,MAX_COPY_PREFETCH
li r11,4
mtctr r0
11: dcbt r11,r4
addi r11,r11,CACHE_LINE_SIZE
bdnz 11b
#else /* MAX_COPY_PREFETCH == 1 */
dcbt r5,r4
li r11,CACHE_LINE_SIZE+4
#endif /* MAX_COPY_PREFETCH */
#endif /* CONFIG_8xx */
li r0,4096/CACHE_LINE_SIZE
mtctr r0
1:
#ifndef CONFIG_8xx
dcbt r11,r4
dcbz r5,r3
#endif
COPY_16_BYTES
#if CACHE_LINE_SIZE >= 32
COPY_16_BYTES
#if CACHE_LINE_SIZE >= 64
COPY_16_BYTES
COPY_16_BYTES
#if CACHE_LINE_SIZE >= 128
COPY_16_BYTES
COPY_16_BYTES
COPY_16_BYTES
COPY_16_BYTES
#endif
#endif
#endif
bdnz 1b
blr
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