4xx_trap_subr.S revision 1.6 
1272343Sngie/*	$NetBSD: 4xx_trap_subr.S,v 1.6 2011/01/18 01:02:53 matt Exp $	*/
2272343Sngie
3272343Sngie/*
4272343Sngie * Copyright 2001 Wasabi Systems, Inc.
5272343Sngie * All rights reserved.
6272343Sngie *
7272343Sngie * Written by Eduardo Horvath and Simon Burge for Wasabi Systems, Inc.
8272343Sngie *
9272343Sngie * Redistribution and use in source and binary forms, with or without
10272343Sngie * modification, are permitted provided that the following conditions
11272343Sngie * are met:
12272343Sngie * 1. Redistributions of source code must retain the above copyright
13272343Sngie *    notice, this list of conditions and the following disclaimer.
14272343Sngie * 2. Redistributions in binary form must reproduce the above copyright
15272343Sngie *    notice, this list of conditions and the following disclaimer in the
16272343Sngie *    documentation and/or other materials provided with the distribution.
17272343Sngie * 3. All advertising materials mentioning features or use of this software
18272343Sngie *    must display the following acknowledgement:
19272343Sngie *      This product includes software developed for the NetBSD Project by
20272343Sngie *      Wasabi Systems, Inc.
21272343Sngie * 4. The name of Wasabi Systems, Inc. may not be used to endorse
22272343Sngie *    or promote products derived from this software without specific prior
23272343Sngie *    written permission.
24272343Sngie *
25272343Sngie * THIS SOFTWARE IS PROVIDED BY WASABI SYSTEMS, INC. ``AS IS'' AND
26272343Sngie * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
27272343Sngie * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
28272343Sngie * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL WASABI SYSTEMS, INC
29272343Sngie * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
30272343Sngie * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
31272343Sngie * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
32272343Sngie * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
33272343Sngie * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
34272343Sngie * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
35272343Sngie * POSSIBILITY OF SUCH DAMAGE.
36272343Sngie */
37272343Sngie
38272343Sngie/* This file provides necessary handlers for 405GP CPU
39272343Sngie * It should be included in locore.S after powerpc/powerpc/trap_subr.S
40274626Sngie */
41272343Sngie
42272979Sngie	.text
43272343Sngie	.globl	_C_LABEL(pitfitwdog),_C_LABEL(pitfitwdogsize)
44272343Sngie
45272343Sngie	.align 4
46272343Sngie_C_LABEL(pitfitwdog):
47272343Sngie	sync
48272343Sngie	ba	pitint
49272343Sngie	.align 4
50272343Sngie	sync
51272343Sngie	ba	fitint
52272343Sngie	.align 4
53272343Sngie	sync
54272343Sngie	ba	wdoghandler
55272343Sngie_C_LABEL(pitfitwdogsize) = .-_C_LABEL(pitfitwdog)
56272343Sngie
57272343Sngiepithandler:
58272343Sngie	rfi
59272343Sngie	ba	.	/* Protect against prefetch */
60272343Sngie
61272343Sngiewdoghandler:
62272343Sngie	rfi
63272343Sngie	ba	.	/* Protect against prefetch */
64272343Sngie
65272343Sngie#define	TLBSTK	0x1000
66272343Sngie	.lcomm	tlbstack,TLBSTK,4
67272343Sngie	.type	tlbstack,@object
68272343Sngie
69272343Sngie	.text
70272343Sngie/* If an unaligned excception (0x600) and DTLB miss exception (0x1100)
71272343Sngie   occur at the same time, the interrupt vector offsets of the two
72272343Sngie   exceptions are logically OR'ed together to produce 0x1700.
73272343Sngie   See PPC405GP Rev D/E Errata item 51 */
74272343Sngie
75272343Sngie	.globl _C_LABEL(errata51handler),_C_LABEL(errata51size)
76272343Sngie_C_LABEL(errata51handler):
77272343Sngie	ba	0x1100
78272343Sngie_C_LABEL(errata51size) = .-_C_LABEL(errata51handler)
79272343Sngie
80272343Sngie	.globl _C_LABEL(tlbdmiss4xx),_C_LABEL(tlbdm4size)
81272343Sngie_C_LABEL(tlbdmiss4xx):
82272343Sngie	ACCESS_PROLOG(CI_TLBMISSSAVE)
83272343Sngie	bla	s4xx_miss
84272343Sngie_C_LABEL(tlbdm4size) = .-_C_LABEL(tlbdmiss4xx)
85272343Sngie
86272343Sngie	.globl _C_LABEL(tlbimiss4xx),_C_LABEL(tlbim4size)
87272343Sngie_C_LABEL(tlbimiss4xx):
88272343Sngie	ACCESS_PROLOG(CI_TLBMISSSAVE)
89272343Sngie	bla	s4xx_miss
90272343Sngie_C_LABEL(tlbim4size) = .-_C_LABEL(tlbimiss4xx)
91272343Sngie
92272343Sngies4xx_miss:
93272343Sngie	.globl	_C_LABEL(pmap_tlbmiss)
94272343Sngie
95272343Sngie	/* If the kernel stack would fault, don't use it. */
96	mfpid	%r30
97	li	%r31,KERNEL_PID
98	mtpid	%r31
99	li	%r31,-FRAMELEN
100	tlbsx.	%r31,%r31,%r1
101	mtpid	%r30
102	beq	1f
103
104	/*
105	 * The kernel stack we want to switch to is not in the TLB.
106	 * To solve this problem, we will simulate a kernel
107	 * fault on the kernel stack and let the miss handler
108	 * bring it in, and return from the trap handler.  The
109	 * processor will immediately take the original fault,
110	 * which we should be able to handle with the now-valid
111	 * kernel stack.
112	 */
113
114	/* Switch to tlbstack */
115	addi	%r30,%r1,-FRAMELEN
116	lis	%r1,tlbstack+TLBSTK-CALLFRAMELEN@ha
117	addi	%r1,%r1,tlbstack+TLBSTK-CALLFRAMELEN@l
118	stw	%r30,0(%r1)
119
120	FRAME_SETUP(CI_TLBMISSSAVE)
121
122	/* Take an explicit fault at (kernelstack,pid) */
123	lwz	%r3, FRAMELEN(%r1)
124	li	%r4,KERNEL_PID
125	bl	_C_LABEL(pmap_tlbmiss)
126	/*
127	 * We can retry the old fault or switch stacks and
128	 * take it now.  It's easier to retry.
129	 */
130	mr.	%r3,%r3
131	beq	trapexit
132
133	/* kernel stack not in the pmap? we should panic */
134	trap
135	b	trapagain
1361:
137	FRAME_SETUP(CI_TLBMISSSAVE)
138	lwz	%r3,FRAME_DEAR(%r1)
139	lwz	%r4,FRAME_PID(%r1)
140	bl	_C_LABEL(pmap_tlbmiss)
141	mr.	%r3,%r3
142	beq	trapexit
143
144	/* XXX DEBUG -- make sure we're not on tlbstack */
145	lis	%r3,tlbstack@ha
146	addi	%r3,%r3,tlbstack@l
147	sub	%r7,%r1,%r3
148	twllei	%r7,TLBSTK
149
150	/* PTE not found, time to cause a fault */
151	b	trapagain
152