1 /* SPDX-License-Identifier: GPL-2.0-or-later */ 2 /* 3 * Copyright (C) 2001,2002,2003 Broadcom Corporation 4 */ 5 6 #include <asm/asm.h> 7 #include <asm/regdef.h> 8 #include <asm/mipsregs.h> 9 #include <asm/stackframe.h> 10 #include <asm/cacheops.h> 11 #include <asm/sibyte/board.h> 12 13 #define C0_ERRCTL $26 /* CP0: Error info */ 14 #define C0_CERR_I $27 /* CP0: Icache error */ 15 #define C0_CERR_D $27,1 /* CP0: Dcache error */ 16 17 /* 18 * Based on SiByte sample software cache-err/cerr.S 19 * CVS revision 1.8. Only the 'unrecoverable' case 20 * is changed. 21 */ 22 23 .set mips64 24 .set noreorder 25 .set noat 26 27 /* 28 * sb1_cerr_vec: code to be copied to the Cache Error 29 * Exception vector. The code must be pushed out to memory 30 * (either by copying to Kseg0 and Kseg1 both, or by flushing 31 * the L1 and L2) since it is fetched as 0xa0000100. 32 * 33 * NOTE: Be sure this handler is at most 28 instructions long 34 * since the final 16 bytes of the exception vector memory 35 * (0x170-0x17f) are used to preserve k0, k1, and ra. 36 */ 37 38 LEAF(except_vec2_sb1) 39 /* 40 * If this error is recoverable, we need to exit the handler 41 * without having dirtied any registers. To do this, 42 * save/restore k0 and k1 from low memory (Useg is direct 43 * mapped while ERL=1). Note that we can't save to a 44 * CPU-specific location without ruining a register in the 45 * process. This means we are vulnerable to data corruption 46 * whenever the handler is reentered by a second CPU. 47 */ 48 sd k0,0x170($0) 49 sd k1,0x178($0) 50 51 #ifdef CONFIG_SB1_CEX_ALWAYS_FATAL 52 j handle_vec2_sb1 53 nop 54 #else 55 /* 56 * M_ERRCTL_RECOVERABLE is bit 31, which makes it easy to tell 57 * if we can fast-path out of here for a h/w-recovered error. 58 */ 59 mfc0 k1,C0_ERRCTL 60 bgtz k1,attempt_recovery 61 sll k0,k1,1 62 63 recovered_dcache: 64 /* 65 * Unlock CacheErr-D (which in turn unlocks CacheErr-DPA). 66 * Ought to log the occurrence of this recovered dcache error. 67 */ 68 b recovered 69 mtc0 $0,C0_CERR_D 70 71 attempt_recovery: 72 /* 73 * k0 has C0_ERRCTL << 1, which puts 'DC' at bit 31. Any 74 * Dcache errors we can recover from will take more extensive 75 * processing. For now, they are considered "unrecoverable". 76 * Note that 'DC' becoming set (outside of ERL mode) will 77 * cause 'IC' to clear; so if there's an Icache error, we'll 78 * only find out about it if we recover from this error and 79 * continue executing. 80 */ 81 bltz k0,unrecoverable 82 sll k0,1 83 84 /* 85 * k0 has C0_ERRCTL << 2, which puts 'IC' at bit 31. If an 86 * Icache error isn't indicated, I'm not sure why we got here. 87 * Consider that case "unrecoverable" for now. 88 */ 89 bgez k0,unrecoverable 90 91 attempt_icache_recovery: 92 /* 93 * External icache errors are due to uncorrectable ECC errors 94 * in the L2 cache or Memory Controller and cannot be 95 * recovered here. 96 */ 97 mfc0 k0,C0_CERR_I /* delay slot */ 98 li k1,1 << 26 /* ICACHE_EXTERNAL */ 99 and k1,k0 100 bnez k1,unrecoverable 101 andi k0,0x1fe0 102 103 /* 104 * Since the error is internal, the 'IDX' field from 105 * CacheErr-I is valid and we can just invalidate all blocks 106 * in that set. 107 */ 108 cache Index_Invalidate_I,(0<<13)(k0) 109 cache Index_Invalidate_I,(1<<13)(k0) 110 cache Index_Invalidate_I,(2<<13)(k0) 111 cache Index_Invalidate_I,(3<<13)(k0) 112 113 /* Ought to log this recovered icache error */ 114 115 recovered: 116 /* Restore the saved registers */ 117 ld k0,0x170($0) 118 ld k1,0x178($0) 119 eret 120 121 unrecoverable: 122 /* Unrecoverable Icache or Dcache error; log it and/or fail */ 123 j handle_vec2_sb1 124 nop 125 #endif 126 127 END(except_vec2_sb1) 128 129 LEAF(handle_vec2_sb1) 130 mfc0 k0,CP0_CONFIG 131 li k1,~CONF_CM_CMASK 132 and k0,k0,k1 133 ori k0,k0,CONF_CM_UNCACHED 134 mtc0 k0,CP0_CONFIG 135 136 SSNOP 137 SSNOP 138 SSNOP 139 SSNOP 140 bnezl $0, 1f 141 1: 142 mfc0 k0, CP0_STATUS 143 sll k0, k0, 3 # check CU0 (kernel?) 144 bltz k0, 2f 145 nop 146 147 /* Get a valid Kseg0 stack pointer. Any task's stack pointer 148 * will do, although if we ever want to resume execution we 149 * better not have corrupted any state. */ 150 get_saved_sp 151 move sp, k1 152 153 2: 154 j sb1_cache_error 155 nop 156 157 END(handle_vec2_sb1) 158