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 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 */ 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 37 __INIT 38 39 .set mips64 40 .set noreorder 41 .set noat 42 43 /* 44 * sb1_cerr_vec: code to be copied to the Cache Error 45 * Exception vector. The code must be pushed out to memory 46 * (either by copying to Kseg0 and Kseg1 both, or by flushing 47 * the L1 and L2) since it is fetched as 0xa0000100. 48 * 49 * NOTE: Be sure this handler is at most 28 instructions long 50 * since the final 16 bytes of the exception vector memory 51 * (0x170-0x17f) are used to preserve k0, k1, and ra. 52 */ 53 54LEAF(except_vec2_sb1) 55 /* 56 * If this error is recoverable, we need to exit the handler 57 * without having dirtied any registers. To do this, 58 * save/restore k0 and k1 from low memory (Useg is direct 59 * mapped while ERL=1). Note that we can't save to a 60 * CPU-specific location without ruining a register in the 61 * process. This means we are vulnerable to data corruption 62 * whenever the handler is reentered by a second CPU. 63 */ 64 sd k0,0x170($0) 65 sd k1,0x178($0) 66 67#ifdef CONFIG_SB1_CEX_ALWAYS_FATAL 68 j handle_vec2_sb1 69 nop 70#else 71 /* 72 * M_ERRCTL_RECOVERABLE is bit 31, which makes it easy to tell 73 * if we can fast-path out of here for a h/w-recovered error. 74 */ 75 mfc0 k1,C0_ERRCTL 76 bgtz k1,attempt_recovery 77 sll k0,k1,1 78 79recovered_dcache: 80 /* 81 * Unlock CacheErr-D (which in turn unlocks CacheErr-DPA). 82 * Ought to log the occurence of this recovered dcache error. 83 */ 84 b recovered 85 mtc0 $0,C0_CERR_D 86 87attempt_recovery: 88 /* 89 * k0 has C0_ERRCTL << 1, which puts 'DC' at bit 31. Any 90 * Dcache errors we can recover from will take more extensive 91 * processing. For now, they are considered "unrecoverable". 92 * Note that 'DC' becoming set (outside of ERL mode) will 93 * cause 'IC' to clear; so if there's an Icache error, we'll 94 * only find out about it if we recover from this error and 95 * continue executing. 96 */ 97 bltz k0,unrecoverable 98 sll k0,1 99 100 /* 101 * k0 has C0_ERRCTL << 2, which puts 'IC' at bit 31. If an 102 * Icache error isn't indicated, I'm not sure why we got here. 103 * Consider that case "unrecoverable" for now. 104 */ 105 bgez k0,unrecoverable 106 107attempt_icache_recovery: 108 /* 109 * External icache errors are due to uncorrectable ECC errors 110 * in the L2 cache or Memory Controller and cannot be 111 * recovered here. 112 */ 113 mfc0 k0,C0_CERR_I /* delay slot */ 114 li k1,1 << 26 /* ICACHE_EXTERNAL */ 115 and k1,k0 116 bnez k1,unrecoverable 117 andi k0,0x1fe0 118 119 /* 120 * Since the error is internal, the 'IDX' field from 121 * CacheErr-I is valid and we can just invalidate all blocks 122 * in that set. 123 */ 124 cache Index_Invalidate_I,(0<<13)(k0) 125 cache Index_Invalidate_I,(1<<13)(k0) 126 cache Index_Invalidate_I,(2<<13)(k0) 127 cache Index_Invalidate_I,(3<<13)(k0) 128 129 /* Ought to log this recovered icache error */ 130 131recovered: 132 /* Restore the saved registers */ 133 ld k0,0x170($0) 134 ld k1,0x178($0) 135 eret 136 137unrecoverable: 138 /* Unrecoverable Icache or Dcache error; log it and/or fail */ 139 j handle_vec2_sb1 140 nop 141#endif 142 143END(except_vec2_sb1) 144 145 __FINIT 146 147 LEAF(handle_vec2_sb1) 148 mfc0 k0,CP0_CONFIG 149 li k1,~CONF_CM_CMASK 150 and k0,k0,k1 151 ori k0,k0,CONF_CM_UNCACHED 152 mtc0 k0,CP0_CONFIG 153 154 SSNOP 155 SSNOP 156 SSNOP 157 SSNOP 158 bnezl $0, 1f 1591: 160 mfc0 k0, CP0_STATUS 161 sll k0, k0, 3 # check CU0 (kernel?) 162 bltz k0, 2f 163 nop 164 165 /* Get a valid Kseg0 stack pointer. Any task's stack pointer 166 * will do, although if we ever want to resume execution we 167 * better not have corrupted any state. */ 168 get_saved_sp 169 move sp, k1 170 1712: 172 j sb1_cache_error 173 nop 174 175 END(handle_vec2_sb1) 176