r4xx0.c

Linux内核源代码 为压缩文件 是<<Linux内核>>一书中的源代码

/*
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file "COPYING" in the main directory of this archive
 * for more details.
 *
 * r4xx0.c: R4000 processor variant specific MMU/Cache routines.
 *
 * Copyright (C) 1996 David S. Miller ([e-mail])
 * Copyright (C) 1997, 1998, 1999, 2000 Ralf Baechle [e-mail]
 *
 * To do:
 *
 *  - this code is a overbloated pig
 *  - many of the bug workarounds are not efficient at all, but at
 *    least they are functional ...
 */
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/mm.h>

#include <asm/bcache.h>
#include <asm/io.h>
#include <asm/page.h>
#include <asm/pgtable.h>
#include <asm/system.h>
#include <asm/bootinfo.h>
#include <asm/mmu_context.h>

/* CP0 hazard avoidance. */
#define BARRIER __asm__ __volatile__(".set noreorder\n\t" \
				     "nop; nop; nop; nop; nop; nop;\n\t" \
				     ".set reorder\n\t")

/* Primary cache parameters. */
static int icache_size, dcache_size; /* Size in bytes */
static int ic_lsize, dc_lsize;       /* LineSize in bytes */

/* Secondary cache (if present) parameters. */
static unsigned int scache_size, sc_lsize;	/* Again, in bytes */

#include <asm/cacheops.h>
#include <asm/r4kcache.h>

#undef DEBUG_CACHE

/*
 * Dummy cache handling routines for machines without boardcaches
 */
static void no_sc_noop(void) {}

static struct bcache_ops no_sc_ops = {
	(void *)no_sc_noop, (void *)no_sc_noop,
	(void *)no_sc_noop, (void *)no_sc_noop
};

struct bcache_ops *bcops = &no_sc_ops;

/*
 * On processors with QED R4600 style two set assosicative cache
 * this is the bit which selects the way in the cache for the
 * indexed cachops.
 */
#define icache_waybit (icache_size >> 1)
#define dcache_waybit (dcache_size >> 1)

/*
 * Zero an entire page.  Basically a simple unrolled loop should do the
 * job but we want more performance by saving memory bus bandwidth.  We
 * have five flavours of the routine available for:
 *
 * - 16byte cachelines and no second level cache
 * - 32byte cachelines second level cache
 * - a version which handles the buggy R4600 v1.x
 * - a version which handles the buggy R4600 v2.0
 * - Finally a last version without fancy cache games for the SC and MC
 *   versions of R4000 and R4400.
 */

static void r4k_clear_page_d16(void * page)
{
	__asm__ __volatile__(
		".set\tnoreorder\n\t"
		".set\tnoat\n\t"
		".set\tmips3\n\t"
		"daddiu\t$1,%0,%2\n"
		"1:\tcache\t%3,(%0)\n\t"
		"sd\t$0,(%0)\n\t"
		"sd\t$0,8(%0)\n\t"
		"cache\t%3,16(%0)\n\t"
		"sd\t$0,16(%0)\n\t"
		"sd\t$0,24(%0)\n\t"
		"daddiu\t%0,64\n\t"
		"cache\t%3,-32(%0)\n\t"
		"sd\t$0,-32(%0)\n\t"
		"sd\t$0,-24(%0)\n\t"
		"cache\t%3,-16(%0)\n\t"
		"sd\t$0,-16(%0)\n\t"
		"bne\t$1,%0,1b\n\t"
		"sd\t$0,-8(%0)\n\t"
		".set\tmips0\n\t"
		".set\tat\n\t"
		".set\treorder"
		:"=r" (page)
		:"0" (page),
		 "I" (PAGE_SIZE),
		 "i" (Create_Dirty_Excl_D)
		:"$1","memory");
}

static void r4k_clear_page_d32(void * page)
{
	__asm__ __volatile__(
		".set\tnoreorder\n\t"
		".set\tnoat\n\t"
		".set\tmips3\n\t"
		"daddiu\t$1,%0,%2\n"
		"1:\tcache\t%3,(%0)\n\t"
		"sd\t$0,(%0)\n\t"
		"sd\t$0,8(%0)\n\t"
		"sd\t$0,16(%0)\n\t"
		"sd\t$0,24(%0)\n\t"
		"daddiu\t%0,64\n\t"
		"cache\t%3,-32(%0)\n\t"
		"sd\t$0,-32(%0)\n\t"
		"sd\t$0,-24(%0)\n\t"
		"sd\t$0,-16(%0)\n\t"
		"bne\t$1,%0,1b\n\t"
		"sd\t$0,-8(%0)\n\t"
		".set\tmips0\n\t"
		".set\tat\n\t"
		".set\treorder"
		:"=r" (page)
		:"0" (page),
		 "I" (PAGE_SIZE),
		 "i" (Create_Dirty_Excl_D)
		:"$1","memory");
}


/*
 * This flavour of r4k_clear_page is for the R4600 V1.x.  Cite from the
 * IDT R4600 V1.7 errata:
 *
 *  18. The CACHE instructions Hit_Writeback_Invalidate_D, Hit_Writeback_D,
 *      Hit_Invalidate_D and Create_Dirty_Excl_D should only be
 *      executed if there is no other dcache activity. If the dcache is
 *      accessed for another instruction immeidately preceding when these
 *      cache instructions are executing, it is possible that the dcache 
 *      tag match outputs used by these cache instructions will be 
 *      incorrect. These cache instructions should be preceded by at least
 *      four instructions that are not any kind of load or store 
 *      instruction.
 *
 *      This is not allowed:    lw
 *                              nop
 *                              nop
 *                              nop
 *                              cache       Hit_Writeback_Invalidate_D
 *
 *      This is allowed:        lw
 *                              nop
 *                              nop
 *                              nop
 *                              nop
 *                              cache       Hit_Writeback_Invalidate_D
 */
static void r4k_clear_page_r4600_v1(void * page)
{
	__asm__ __volatile__(
		".set\tnoreorder\n\t"
		".set\tnoat\n\t"
		".set\tmips3\n\t"
		"daddiu\t$1,%0,%2\n"
		"1:\tnop\n\t"
		"nop\n\t"
		"nop\n\t"
		"nop\n\t"
		"cache\t%3,(%0)\n\t"
		"sd\t$0,(%0)\n\t"
		"sd\t$0,8(%0)\n\t"
		"sd\t$0,16(%0)\n\t"
		"sd\t$0,24(%0)\n\t"
		"daddiu\t%0,64\n\t"
		"nop\n\t"
		"nop\n\t"
		"nop\n\t"
		"cache\t%3,-32(%0)\n\t"
		"sd\t$0,-32(%0)\n\t"
		"sd\t$0,-24(%0)\n\t"
		"sd\t$0,-16(%0)\n\t"
		"bne\t$1,%0,1b\n\t"
		"sd\t$0,-8(%0)\n\t"
		".set\tmips0\n\t"
		".set\tat\n\t"
		".set\treorder"
		:"=r" (page)
		:"0" (page),
		 "I" (PAGE_SIZE),
		 "i" (Create_Dirty_Excl_D)
		:"$1","memory");
}

/*
 * And this one is for the R4600 V2.0
 */
static void r4k_clear_page_r4600_v2(void * page)
{
	unsigned int flags;

	save_and_cli(flags);
	*(volatile unsigned int *)KSEG1;
	__asm__ __volatile__(
		".set\tnoreorder\n\t"
		".set\tnoat\n\t"
		".set\tmips3\n\t"
		"daddiu\t$1,%0,%2\n"
		"1:\tcache\t%3,(%0)\n\t"
		"sd\t$0,(%0)\n\t"
		"sd\t$0,8(%0)\n\t"
		"sd\t$0,16(%0)\n\t"
		"sd\t$0,24(%0)\n\t"
		"daddiu\t%0,64\n\t"
		"cache\t%3,-32(%0)\n\t"
		"sd\t$0,-32(%0)\n\t"
		"sd\t$0,-24(%0)\n\t"
		"sd\t$0,-16(%0)\n\t"
		"bne\t$1,%0,1b\n\t"
		"sd\t$0,-8(%0)\n\t"
		".set\tmips0\n\t"
		".set\tat\n\t"
		".set\treorder"
		:"=r" (page)
		:"0" (page),
		 "I" (PAGE_SIZE),
		 "i" (Create_Dirty_Excl_D)
		:"$1","memory");
	restore_flags(flags);
}

/*
 * The next 4 versions are optimized for all possible scache configurations
 * of the SC / MC versions of R4000 and R4400 ...
 *
 * Todo: For even better performance we should have a routine optimized for
 * every legal combination of dcache / scache linesize.  When I (Ralf) tried
 * this the kernel crashed shortly after mounting the root filesystem.  CPU
 * bug?  Weirdo cache instruction semantics?
 */
static void r4k_clear_page_s16(void * page)
{
	__asm__ __volatile__(
		".set\tnoreorder\n\t"
		".set\tnoat\n\t"
		".set\tmips3\n\t"
		"daddiu\t$1,%0,%2\n"
		"1:\tcache\t%3,(%0)\n\t"
		"sd\t$0,(%0)\n\t"
		"sd\t$0,8(%0)\n\t"
		"cache\t%3,16(%0)\n\t"
		"sd\t$0,16(%0)\n\t"
		"sd\t$0,24(%0)\n\t"
		"daddiu\t%0,64\n\t"
		"cache\t%3,-32(%0)\n\t"
		"sd\t$0,-32(%0)\n\t"
		"sd\t$0,-24(%0)\n\t"
		"cache\t%3,-16(%0)\n\t"
		"sd\t$0,-16(%0)\n\t"
		"bne\t$1,%0,1b\n\t"
		"sd\t$0,-8(%0)\n\t"
		".set\tmips0\n\t"
		".set\tat\n\t"
		".set\treorder"
		:"=r" (page)
		:"0" (page),
		 "I" (PAGE_SIZE),
		 "i" (Create_Dirty_Excl_SD)
		:"$1","memory");
}

static void r4k_clear_page_s32(void * page)
{
	__asm__ __volatile__(
		".set\tnoreorder\n\t"
		".set\tnoat\n\t"
		".set\tmips3\n\t"
		"daddiu\t$1,%0,%2\n"
		"1:\tcache\t%3,(%0)\n\t"
		"sd\t$0,(%0)\n\t"
		"sd\t$0,8(%0)\n\t"
		"sd\t$0,16(%0)\n\t"
		"sd\t$0,24(%0)\n\t"
		"daddiu\t%0,64\n\t"
		"cache\t%3,-32(%0)\n\t"
		"sd\t$0,-32(%0)\n\t"
		"sd\t$0,-24(%0)\n\t"
		"sd\t$0,-16(%0)\n\t"
		"bne\t$1,%0,1b\n\t"
		"sd\t$0,-8(%0)\n\t"
		".set\tmips0\n\t"
		".set\tat\n\t"
		".set\treorder"
		:"=r" (page)
		:"0" (page),
		 "I" (PAGE_SIZE),
		 "i" (Create_Dirty_Excl_SD)
		:"$1","memory");
}

static void r4k_clear_page_s64(void * page)
{
	__asm__ __volatile__(
		".set\tnoreorder\n\t"
		".set\tnoat\n\t"
		".set\tmips3\n\t"
		"daddiu\t$1,%0,%2\n"
		"1:\tcache\t%3,(%0)\n\t"
		"sd\t$0,(%0)\n\t"
		"sd\t$0,8(%0)\n\t"
		"sd\t$0,16(%0)\n\t"
		"sd\t$0,24(%0)\n\t"
		"daddiu\t%0,64\n\t"
		"sd\t$0,-32(%0)\n\t"
		"sd\t$0,-24(%0)\n\t"
		"sd\t$0,-16(%0)\n\t"
		"bne\t$1,%0,1b\n\t"
		"sd\t$0,-8(%0)\n\t"
		".set\tmips0\n\t"
		".set\tat\n\t"
		".set\treorder"
		:"=r" (page)
		:"0" (page),
		 "I" (PAGE_SIZE),
		 "i" (Create_Dirty_Excl_SD)
		:"$1","memory");
}

static void r4k_clear_page_s128(void * page)
{
	__asm__ __volatile__(
		".set\tnoreorder\n\t"
		".set\tnoat\n\t"
		".set\tmips3\n\t"
		"daddiu\t$1,%0,%2\n"
		"1:\tcache\t%3,(%0)\n\t"
		"sd\t$0,(%0)\n\t"
		"sd\t$0,8(%0)\n\t"
		"sd\t$0,16(%0)\n\t"
		"sd\t$0,24(%0)\n\t"
		"sd\t$0,32(%0)\n\t"
		"sd\t$0,40(%0)\n\t"
		"sd\t$0,48(%0)\n\t"
		"sd\t$0,56(%0)\n\t"
		"daddiu\t%0,128\n\t"
		"sd\t$0,-64(%0)\n\t"
		"sd\t$0,-56(%0)\n\t"
		"sd\t$0,-48(%0)\n\t"
		"sd\t$0,-40(%0)\n\t"
		"sd\t$0,-32(%0)\n\t"
		"sd\t$0,-24(%0)\n\t"
		"sd\t$0,-16(%0)\n\t"
		"bne\t$1,%0,1b\n\t"
		"sd\t$0,-8(%0)\n\t"
		".set\tmips0\n\t"
		".set\tat\n\t"
		".set\treorder"
		:"=r" (page)
		:"0" (page),
		 "I" (PAGE_SIZE),
		 "i" (Create_Dirty_Excl_SD)
		:"$1","memory");
}


/*
 * This is still inefficient.  We only can do better if we know the
 * virtual address where the copy will be accessed.
 */

static void r4k_copy_page_d16(void * to, void * from)
{
	unsigned long dummy1, dummy2;
	unsigned long reg1, reg2, reg3, reg4;

	__asm__ __volatile__(
		".set\tnoreorder\n\t"
		".set\tnoat\n\t"
		".set\tmips3\n\t"
		"daddiu\t$1,%0,%8\n"
		"1:\tcache\t%9,(%0)\n\t"
		"lw\t%2,(%1)\n\t"
		"lw\t%3,4(%1)\n\t"
		"lw\t%4,8(%1)\n\t"
		"lw\t%5,12(%1)\n\t"
		"sw\t%2,(%0)\n\t"
		"sw\t%3,4(%0)\n\t"
		"sw\t%4,8(%0)\n\t"
		"sw\t%5,12(%0)\n\t"
		"cache\t%9,16(%0)\n\t"
		"lw\t%2,16(%1)\n\t"
		"lw\t%3,20(%1)\n\t"
		"lw\t%4,24(%1)\n\t"
		"lw\t%5,28(%1)\n\t"
		"sw\t%2,16(%0)\n\t"
		"sw\t%3,20(%0)\n\t"
		"sw\t%4,24(%0)\n\t"
		"sw\t%5,28(%0)\n\t"
		"cache\t%9,32(%0)\n\t"
		"daddiu\t%0,64\n\t"
		"daddiu\t%1,64\n\t"
		"lw\t%2,-32(%1)\n\t"
		"lw\t%3,-28(%1)\n\t"
		"lw\t%4,-24(%1)\n\t"
		"lw\t%5,-20(%1)\n\t"
		"sw\t%2,-32(%0)\n\t"
		"sw\t%3,-28(%0)\n\t"
		"sw\t%4,-24(%0)\n\t"
		"sw\t%5,-20(%0)\n\t"
		"cache\t%9,-16(%0)\n\t"
		"lw\t%2,-16(%1)\n\t"
		"lw\t%3,-12(%1)\n\t"
		"lw\t%4,-8(%1)\n\t"
		"lw\t%5,-4(%1)\n\t"
		"sw\t%2,-16(%0)\n\t"
		"sw\t%3,-12(%0)\n\t"
		"sw\t%4,-8(%0)\n\t"
		"bne\t$1,%0,1b\n\t"
		"sw\t%5,-4(%0)\n\t"
		".set\tmips0\n\t"
		".set\tat\n\t"
		".set\treorder"
		:"=r" (dummy1), "=r" (dummy2),
		 "=&r" (reg1), "=&r" (reg2), "=&r" (reg3), "=&r" (reg4)
		:"0" (to), "1" (from),
		 "I" (PAGE_SIZE),
		 "i" (Create_Dirty_Excl_D));
}

static void r4k_copy_page_d32(void * to, void * from)
{
	unsigned long dummy1, dummy2;
	unsigned long reg1, reg2, reg3, reg4;

	__asm__ __volatile__(
		".set\tnoreorder\n\t"
		".set\tnoat\n\t"
		".set\tmips3\n\t"
		"daddiu\t$1,%0,%8\n"
		"1:\tcache\t%9,(%0)\n\t"
		"lw\t%2,(%1)\n\t"
		"lw\t%3,4(%1)\n\t"
		"lw\t%4,8(%1)\n\t"
		"lw\t%5,12(%1)\n\t"
		"sw\t%2,(%0)\n\t"
		"sw\t%3,4(%0)\n\t"
		"sw\t%4,8(%0)\n\t"
		"sw\t%5,12(%0)\n\t"
		"lw\t%2,16(%1)\n\t"
		"lw\t%3,20(%1)\n\t"
		"lw\t%4,24(%1)\n\t"
		"lw\t%5,28(%1)\n\t"
		"sw\t%2,16(%0)\n\t"
		"sw\t%3,20(%0)\n\t"
		"sw\t%4,24(%0)\n\t"
		"sw\t%5,28(%0)\n\t"
		"cache\t%9,32(%0)\n\t"
		"daddiu\t%0,64\n\t"
		"daddiu\t%1,64\n\t"
		"lw\t%2,-32(%1)\n\t"
		"lw\t%3,-28(%1)\n\t"
		"lw\t%4,-24(%1)\n\t"
		"lw\t%5,-20(%1)\n\t"
		"sw\t%2,-32(%0)\n\t"
		"sw\t%3,-28(%0)\n\t"
		"sw\t%4,-24(%0)\n\t"
		"sw\t%5,-20(%0)\n\t"
		"lw\t%2,-16(%1)\n\t"
		"lw\t%3,-12(%1)\n\t"
		"lw\t%4,-8(%1)\n\t"
		"lw\t%5,-4(%1)\n\t"
		"sw\t%2,-16(%0)\n\t"
		"sw\t%3,-12(%0)\n\t"
		"sw\t%4,-8(%0)\n\t"
		"bne\t$1,%0,1b\n\t"
		"sw\t%5,-4(%0)\n\t"
		".set\tmips0\n\t"
		".set\tat\n\t"
		".set\treorder"
		:"=r" (dummy1), "=r" (dummy2),
		 "=&r" (reg1), "=&r" (reg2), "=&r" (reg3), "=&r" (reg4)
		:"0" (to), "1" (from),
		 "I" (PAGE_SIZE),
		 "i" (Create_Dirty_Excl_D));
}

/*
 * Again a special version for the R4600 V1.x
 */
static void r4k_copy_page_r4600_v1(void * to, void * from)
{
	unsigned long dummy1, dummy2;
	unsigned long reg1, reg2, reg3, reg4;

	__asm__ __volatile__(
		".set\tnoreorder\n\t"
		".set\tnoat\n\t"
		".set\tmips3\n\t"
		"daddiu\t$1,%0,%8\n"
		"1:\tnop\n\t"
		"nop\n\t"
		"nop\n\t"
		"nop\n\t"
		"\tcache\t%9,(%0)\n\t"
		"lw\t%2,(%1)\n\t"
		"lw\t%3,4(%1)\n\t"
		"lw\t%4,8(%1)\n\t"
		"lw\t%5,12(%1)\n\t"
		"sw\t%2,(%0)\n\t"
		"sw\t%3,4(%0)\n\t"
		"sw\t%4,8(%0)\n\t"
		"sw\t%5,12(%0)\n\t"
		"lw\t%2,16(%1)\n\t"
		"lw\t%3,20(%1)\n\t"
		"lw\t%4,24(%1)\n\t"
		"lw\t%5,28(%1)\n\t"
		"sw\t%2,16(%0)\n\t"
		"sw\t%3,20(%0)\n\t"
		"sw\t%4,24(%0)\n\t"
		"sw\t%5,28(%0)\n\t"
		"nop\n\t"
		"nop\n\t"
		"nop\n\t"
		"nop\n\t"
		"cache\t%9,32(%0)\n\t"
		"daddiu\t%0,64\n\t"
		"daddiu\t%1,64\n\t"
		"lw\t%2,-32(%1)\n\t"
		"lw\t%3,-28(%1)\n\t"
		"lw\t%4,-24(%1)\n\t"
		"lw\t%5,-20(%1)\n\t"
		"sw\t%2,-32(%0)\n\t"
		"sw\t%3,-28(%0)\n\t"
		"sw\t%4,-24(%0)\n\t"
		"sw\t%5,-20(%0)\n\t"
		"lw\t%2,-16(%1)\n\t"
		"lw\t%3,-12(%1)\n\t"
		"lw\t%4,-8(%1)\n\t"
		"lw\t%5,-4(%1)\n\t"