4xx_trap_subr.S revision 1.3 
1/*	$NetBSD: 4xx_trap_subr.S,v 1.3 2003/03/11 10:40:16 hannken Exp $	*/
2
3/*
4 * Copyright 2001 Wasabi Systems, Inc.
5 * All rights reserved.
6 *
7 * Written by Eduardo Horvath and Simon Burge for Wasabi Systems, Inc.
8 *
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
11 * are met:
12 * 1. Redistributions of source code must retain the above copyright
13 *    notice, this list of conditions and the following disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 *    notice, this list of conditions and the following disclaimer in the
16 *    documentation and/or other materials provided with the distribution.
17 * 3. All advertising materials mentioning features or use of this software
18 *    must display the following acknowledgement:
19 *      This product includes software developed for the NetBSD Project by
20 *      Wasabi Systems, Inc.
21 * 4. The name of Wasabi Systems, Inc. may not be used to endorse
22 *    or promote products derived from this software without specific prior
23 *    written permission.
24 *
25 * THIS SOFTWARE IS PROVIDED BY WASABI SYSTEMS, INC. ``AS IS'' AND
26 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
27 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
28 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL WASABI SYSTEMS, INC
29 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
30 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
31 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
32 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
33 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
34 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
35 * POSSIBILITY OF SUCH DAMAGE.
36 */
37
38/* This file provides necessary handlers for 405GP CPU
39 * It should be included in locore.S after powerpc/powerpc/trap_subr.S
40 */
41
42	.text
43	.globl	_C_LABEL(pitfitwdog),_C_LABEL(pitfitwdogsize)
44
45	.align 4
46_C_LABEL(pitfitwdog):
47	sync
48	ba	pitint
49	.align 4
50	sync
51	ba	fitint
52	.align 4
53	sync
54	ba	wdoghandler
55_C_LABEL(pitfitwdogsize) = .-_C_LABEL(pitfitwdog)
56
57pithandler:
58	rfi
59	ba	.	/* Protect against prefetch */
60
61wdoghandler:
62	rfi
63	ba	.	/* Protect against prefetch */
64
65#define	tlbstacksize	0x1000
66#define	tlbsave		0x3000
67#define tlbstack	tlbsave+tlbstacksize
68
69/* If an unaligned excception (0x600) and DTLB miss exception (0x1100)
70   occur at the same time, the interrupt vector offsets of the two
71   exceptions are logically OR'ed together to produce 0x1700.
72   See PPC405GP Rev D/E Errata item 51 */
73
74	.globl _C_LABEL(errata51handler),_C_LABEL(errata51size)
75_C_LABEL(errata51handler):
76	ba	0x1100
77_C_LABEL(errata51size) = .-_C_LABEL(errata51handler)
78
79	.globl _C_LABEL(tlbdmiss4xx),_C_LABEL(tlbdm4size)
80_C_LABEL(tlbdmiss4xx):
81	STANDARD_PROLOG(tlbsave)
82	mfdear	r30		/* Get fault address */
83	mfesr	r31
84	stmw	r30,16+tlbsave(0)
85	bla	s4xx_miss
86_C_LABEL(tlbdm4size) = .-_C_LABEL(tlbdmiss4xx)
87
88	.globl _C_LABEL(tlbimiss4xx),_C_LABEL(tlbim4size)
89_C_LABEL(tlbimiss4xx):
90	STANDARD_PROLOG(tlbsave)
91	mfsrr0	r30		/* XXX Get fault address */
92	mfesr	r31
93	stmw	r30,16+tlbsave(0)
94	bla	s4xx_miss
95_C_LABEL(tlbim4size) = .-_C_LABEL(tlbimiss4xx)
96
97s4xx_miss:
98	.globl	_C_LABEL(pmap_tlbmiss)
99
100	/* If the kernel stack would fault, don't use it. */
101	mfpid	r30
102	li	r31,KERNEL_PID
103	mtpid	r31
104	li	r31,-FRAMELEN
105	tlbsx.	r31,r31,r1
106	mtpid	r30
107	beq	1f
108
109	/*
110	 * The kernel we want to switch to is not in the TLB.
111	 * To solve this problem, we will simulate a kernel
112	 * fault on the kernel stack and let the miss handler
113	 * bring it in, and return from the trap handler.  The
114	 * processor will immediately take the original fault,
115	 * which we should be able to handle with the now-valid
116	 * kernel stack.
117	 */
118
119	/* Switch to tlbstack */
120	addi	r30,r1,-FRAMELEN
121	lis	r1,tlbstack@ha
122	addi	r1,r1,tlbstack@l
123	stw	r30,4(1)
124
125	FRAME_SETUP(tlbsave)
126
127	/* Take an explicit fault at (kernelstack,pid) */
128	lwz	r3, tlbstack+4(0)
129	li	r4,KERNEL_PID
130	bl	_C_LABEL(pmap_tlbmiss)
131	/*
132	 * We can retry the old fault or switch stacks and
133	 * take it now.  It's easier to retry.
134	 */
135	mr.	r3,r3
136	beq	2f
137
138	/* kernel stack not in the pmap? we should panic */
139	trap
140	ba	trapagain
1411:
142	FRAME_SETUP(tlbsave)
143	lwz	r3,FRAME_DEAR+8(1)
144	lwz	r4,FRAME_PID+8(1)
145	bl	_C_LABEL(pmap_tlbmiss)
146	mr.	r3,r3
147	beq	2f
148
149	/* XXX DEBUG -- make sure we're not on tlbstack */
150	addi	r7,r1,-tlbsave
151	twllei	r7,(tlbstacksize)
152
153	/* PTE not found, time to cause a fault */
154	ba	trapagain
1552:
156	FRAME_LEAVE(tlbsave)
157	rfi
158	ba	.	/* Protect against prefetch */
159