/* * 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 <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