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1da177e4 LT |
1 | /* |
2 | * Copyright (C) 2001,2002,2003 Broadcom Corporation | |
3 | * | |
4 | * This program is free software; you can redistribute it and/or | |
5 | * modify it under the terms of the GNU General Public License | |
6 | * as published by the Free Software Foundation; either version 2 | |
7 | * of the License, or (at your option) any later version. | |
8 | * | |
9 | * This program is distributed in the hope that it will be useful, | |
10 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
11 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
12 | * GNU General Public License for more details. | |
13 | * | |
14 | * You should have received a copy of the GNU General Public License | |
15 | * along with this program; if not, write to the Free Software | |
16 | * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. | |
17 | */ | |
18 | #include <linux/init.h> | |
19 | ||
20 | #include <asm/asm.h> | |
21 | #include <asm/regdef.h> | |
22 | #include <asm/mipsregs.h> | |
23 | #include <asm/stackframe.h> | |
24 | #include <asm/cacheops.h> | |
25 | #include <asm/sibyte/board.h> | |
26 | ||
70342287 RB |
27 | #define C0_ERRCTL $26 /* CP0: Error info */ |
28 | #define C0_CERR_I $27 /* CP0: Icache error */ | |
29 | #define C0_CERR_D $27,1 /* CP0: Dcache error */ | |
1da177e4 LT |
30 | |
31 | /* | |
32 | * Based on SiByte sample software cache-err/cerr.S | |
33 | * CVS revision 1.8. Only the 'unrecoverable' case | |
34 | * is changed. | |
35 | */ | |
36 | ||
1da177e4 LT |
37 | .set mips64 |
38 | .set noreorder | |
39 | .set noat | |
40 | ||
41 | /* | |
42 | * sb1_cerr_vec: code to be copied to the Cache Error | |
43 | * Exception vector. The code must be pushed out to memory | |
44 | * (either by copying to Kseg0 and Kseg1 both, or by flushing | |
45 | * the L1 and L2) since it is fetched as 0xa0000100. | |
46 | * | |
47 | * NOTE: Be sure this handler is at most 28 instructions long | |
48 | * since the final 16 bytes of the exception vector memory | |
49 | * (0x170-0x17f) are used to preserve k0, k1, and ra. | |
50 | */ | |
51 | ||
52 | LEAF(except_vec2_sb1) | |
53 | /* | |
54 | * If this error is recoverable, we need to exit the handler | |
55 | * without having dirtied any registers. To do this, | |
56 | * save/restore k0 and k1 from low memory (Useg is direct | |
57 | * mapped while ERL=1). Note that we can't save to a | |
58 | * CPU-specific location without ruining a register in the | |
59 | * process. This means we are vulnerable to data corruption | |
60 | * whenever the handler is reentered by a second CPU. | |
61 | */ | |
62 | sd k0,0x170($0) | |
63 | sd k1,0x178($0) | |
64 | ||
51939fbb | 65 | #ifdef CONFIG_SB1_CEX_ALWAYS_FATAL |
a4b5bd9a AI |
66 | j handle_vec2_sb1 |
67 | nop | |
68 | #else | |
1da177e4 LT |
69 | /* |
70 | * M_ERRCTL_RECOVERABLE is bit 31, which makes it easy to tell | |
71 | * if we can fast-path out of here for a h/w-recovered error. | |
72 | */ | |
73 | mfc0 k1,C0_ERRCTL | |
74 | bgtz k1,attempt_recovery | |
75 | sll k0,k1,1 | |
76 | ||
77 | recovered_dcache: | |
78 | /* | |
79 | * Unlock CacheErr-D (which in turn unlocks CacheErr-DPA). | |
25985edc | 80 | * Ought to log the occurrence of this recovered dcache error. |
1da177e4 LT |
81 | */ |
82 | b recovered | |
83 | mtc0 $0,C0_CERR_D | |
84 | ||
85 | attempt_recovery: | |
86 | /* | |
87 | * k0 has C0_ERRCTL << 1, which puts 'DC' at bit 31. Any | |
88 | * Dcache errors we can recover from will take more extensive | |
70342287 | 89 | * processing. For now, they are considered "unrecoverable". |
1da177e4 LT |
90 | * Note that 'DC' becoming set (outside of ERL mode) will |
91 | * cause 'IC' to clear; so if there's an Icache error, we'll | |
92 | * only find out about it if we recover from this error and | |
93 | * continue executing. | |
94 | */ | |
95 | bltz k0,unrecoverable | |
96 | sll k0,1 | |
97 | ||
98 | /* | |
99 | * k0 has C0_ERRCTL << 2, which puts 'IC' at bit 31. If an | |
100 | * Icache error isn't indicated, I'm not sure why we got here. | |
101 | * Consider that case "unrecoverable" for now. | |
102 | */ | |
103 | bgez k0,unrecoverable | |
104 | ||
105 | attempt_icache_recovery: | |
106 | /* | |
107 | * External icache errors are due to uncorrectable ECC errors | |
108 | * in the L2 cache or Memory Controller and cannot be | |
109 | * recovered here. | |
110 | */ | |
111 | mfc0 k0,C0_CERR_I /* delay slot */ | |
112 | li k1,1 << 26 /* ICACHE_EXTERNAL */ | |
113 | and k1,k0 | |
114 | bnez k1,unrecoverable | |
115 | andi k0,0x1fe0 | |
116 | ||
117 | /* | |
118 | * Since the error is internal, the 'IDX' field from | |
119 | * CacheErr-I is valid and we can just invalidate all blocks | |
120 | * in that set. | |
121 | */ | |
122 | cache Index_Invalidate_I,(0<<13)(k0) | |
123 | cache Index_Invalidate_I,(1<<13)(k0) | |
124 | cache Index_Invalidate_I,(2<<13)(k0) | |
125 | cache Index_Invalidate_I,(3<<13)(k0) | |
126 | ||
127 | /* Ought to log this recovered icache error */ | |
128 | ||
129 | recovered: | |
130 | /* Restore the saved registers */ | |
131 | ld k0,0x170($0) | |
132 | ld k1,0x178($0) | |
133 | eret | |
134 | ||
135 | unrecoverable: | |
136 | /* Unrecoverable Icache or Dcache error; log it and/or fail */ | |
137 | j handle_vec2_sb1 | |
138 | nop | |
a4b5bd9a | 139 | #endif |
1da177e4 LT |
140 | |
141 | END(except_vec2_sb1) | |
142 | ||
1da177e4 LT |
143 | LEAF(handle_vec2_sb1) |
144 | mfc0 k0,CP0_CONFIG | |
145 | li k1,~CONF_CM_CMASK | |
146 | and k0,k0,k1 | |
147 | ori k0,k0,CONF_CM_UNCACHED | |
148 | mtc0 k0,CP0_CONFIG | |
149 | ||
150 | SSNOP | |
151 | SSNOP | |
152 | SSNOP | |
153 | SSNOP | |
154 | bnezl $0, 1f | |
155 | 1: | |
156 | mfc0 k0, CP0_STATUS | |
157 | sll k0, k0, 3 # check CU0 (kernel?) | |
158 | bltz k0, 2f | |
159 | nop | |
160 | ||
161 | /* Get a valid Kseg0 stack pointer. Any task's stack pointer | |
162 | * will do, although if we ever want to resume execution we | |
163 | * better not have corrupted any state. */ | |
164 | get_saved_sp | |
165 | move sp, k1 | |
166 | ||
167 | 2: | |
168 | j sb1_cache_error | |
169 | nop | |
170 | ||
171 | END(handle_vec2_sb1) |