linux/arch/mn10300/mm/tlb-mn10300.S

###############################################################################
#
# TLB loading functions
#
# Copyright (C) 2007 Matsushita Electric Industrial Co., Ltd.
# Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
# Modified by David Howells (dhowells@redhat.com)
#
# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public Licence
# as published by the Free Software Foundation; either version
# 2 of the Licence, or (at your option) any later version.
#
###############################################################################
#include <linux/sys.h>
#include <linux/linkage.h>
#include <asm/smp.h>
#include <asm/intctl-regs.h>
#include <asm/frame.inc>
#include <asm/page.h>
#include <asm/pgtable.h>

###############################################################################
#
# Instruction TLB Miss handler entry point
#
###############################################################################
	.type	itlb_miss,@function
ENTRY(itlb_miss)
	and	~EPSW_NMID,epsw
#ifdef CONFIG_GDBSTUB
	movm	[d2,d3,a2],(sp)
#else
	or	EPSW_nAR,epsw		# switch D0-D3 & A0-A3 to the alternate
					# register bank
	nop
	nop
	nop
#endif

	mov	(IPTEU),d3
	mov	(PTBR),a2
	mov	d3,d2
	and	0xffc00000,d2
	lsr	20,d2
	mov	(a2,d2),a2		# PTD *ptd = PGD[addr 31..22]
	btst	_PAGE_VALID,a2
	beq	itlb_miss_fault		# jump if doesn't point anywhere

	and	~(PAGE_SIZE-1),a2
	mov	d3,d2
	and	0x003ff000,d2
	lsr	10,d2
	add	d2,a2
	mov	(a2),d2			# get pte from PTD[addr 21..12]
	btst	_PAGE_VALID,d2
	beq	itlb_miss_fault		# jump if doesn't point to a page
					# (might be a swap id)
	bset	_PAGE_ACCESSED,(0,a2)
	and	~(xPTEL_UNUSED1|xPTEL_UNUSED2),d2
itlb_miss_set:
	mov	d2,(IPTEL)		# change the TLB
#ifdef CONFIG_GDBSTUB
	movm	(sp),[d2,d3,a2]
#endif
	rti

itlb_miss_fault:
	mov	_PAGE_VALID,d2		# force address error handler to be
					# invoked
	bra	itlb_miss_set

	.size	itlb_miss, . - itlb_miss

###############################################################################
#
# Data TLB Miss handler entry point
#
###############################################################################
	.type	dtlb_miss,@function
ENTRY(dtlb_miss)
	and	~EPSW_NMID,epsw
#ifdef CONFIG_GDBSTUB
	movm	[d2,d3,a2],(sp)
#else
	or	EPSW_nAR,epsw		# switch D0-D3 & A0-A3 to the alternate
					# register bank
	nop
	nop
	nop
#endif

	mov	(DPTEU),d3
	mov	(PTBR),a2
	mov	d3,d2
	and	0xffc00000,d2
	lsr	20,d2
	mov	(a2,d2),a2		# PTD *ptd = PGD[addr 31..22]
	btst	_PAGE_VALID,a2
	beq	dtlb_miss_fault		# jump if doesn't point anywhere

	and	~(PAGE_SIZE-1),a2
	mov	d3,d2
	and	0x003ff000,d2
	lsr	10,d2
	add	d2,a2
	mov	(a2),d2			# get pte from PTD[addr 21..12]
	btst	_PAGE_VALID,d2
	beq	dtlb_miss_fault		# jump if doesn't point to a page
					# (might be a swap id)
	bset	_PAGE_ACCESSED,(0,a2)
	and	~(xPTEL_UNUSED1|xPTEL_UNUSED2),d2
dtlb_miss_set:
	mov	d2,(DPTEL)		# change the TLB
#ifdef CONFIG_GDBSTUB
	movm	(sp),[d2,d3,a2]
#endif
	rti

dtlb_miss_fault:
	mov	_PAGE_VALID,d2		# force address error handler to be
					# invoked
	bra	dtlb_miss_set
	.size	dtlb_miss, . - dtlb_miss

###############################################################################
#
# Instruction TLB Address Error handler entry point
#
###############################################################################
	.type	itlb_aerror,@function
ENTRY(itlb_aerror)
	and	~EPSW_NMID,epsw
	add	-4,sp
	SAVE_ALL
	add	-4,sp				# need to pass three params

	# calculate the fault code
	movhu	(MMUFCR_IFC),d1
	or	0x00010000,d1			# it's an instruction fetch

	# determine the page address
	mov	(IPTEU),a2
	mov	a2,d0
	and	PAGE_MASK,d0
	mov	d0,(12,sp)

	clr	d0
	mov	d0,(IPTEL)

	and	~EPSW_NMID,epsw
	or	EPSW_IE,epsw
	mov	fp,d0
	call	do_page_fault[],0		# do_page_fault(regs,code,addr

	jmp	ret_from_exception
	.size	itlb_aerror, . - itlb_aerror

###############################################################################
#
# Data TLB Address Error handler entry point
#
###############################################################################
	.type	dtlb_aerror,@function
ENTRY(dtlb_aerror)
	and	~EPSW_NMID,epsw
	add	-4,sp
	mov	d1,(sp)

	movhu	(MMUFCR_DFC),d1			# is it the initial valid write
						# to this page?
	and	MMUFCR_xFC_INITWR,d1
 	beq	dtlb_pagefault			# jump if not

	mov	(DPTEL),d1			# set the dirty bit
						# (don't replace with BSET!)
	or	_PAGE_DIRTY,d1
	mov	d1,(DPTEL)
	mov	(sp),d1
	add	4,sp
 	rti

	ALIGN
dtlb_pagefault:
	mov	(sp),d1
	SAVE_ALL
	add	-4,sp				# need to pass three params

	# calculate the fault code
	movhu	(MMUFCR_DFC),d1

	# determine the page address
	mov	(DPTEU),a2
	mov	a2,d0
	and	PAGE_MASK,d0
	mov	d0,(12,sp)

	clr	d0
	mov	d0,(DPTEL)

	and	~EPSW_NMID,epsw
	or	EPSW_IE,epsw
	mov	fp,d0
	call	do_page_fault[],0		# do_page_fault(regs,code,addr

	jmp	ret_from_exception
	.size	dtlb_aerror, . - dtlb_aerror