1 /* 2 * Machine check exception handling. 3 * 4 * This program is free software; you can redistribute it and/or modify 5 * it under the terms of the GNU General Public License as published by 6 * the Free Software Foundation; either version 2 of the License, or 7 * (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 * Copyright 2013 IBM Corporation 19 * Author: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com> 20 */ 21 22 #undef DEBUG 23 #define pr_fmt(fmt) "mce: " fmt 24 25 #include <linux/types.h> 26 #include <linux/ptrace.h> 27 #include <linux/percpu.h> 28 #include <linux/export.h> 29 #include <linux/irq_work.h> 30 #include <asm/mce.h> 31 32 static DEFINE_PER_CPU(int, mce_nest_count); 33 static DEFINE_PER_CPU(struct machine_check_event[MAX_MC_EVT], mce_event); 34 35 /* Queue for delayed MCE events. */ 36 static DEFINE_PER_CPU(int, mce_queue_count); 37 static DEFINE_PER_CPU(struct machine_check_event[MAX_MC_EVT], mce_event_queue); 38 39 static void machine_check_process_queued_event(struct irq_work *work); 40 struct irq_work mce_event_process_work = { 41 .func = machine_check_process_queued_event, 42 }; 43 44 static void mce_set_error_info(struct machine_check_event *mce, 45 struct mce_error_info *mce_err) 46 { 47 mce->error_type = mce_err->error_type; 48 switch (mce_err->error_type) { 49 case MCE_ERROR_TYPE_UE: 50 mce->u.ue_error.ue_error_type = mce_err->u.ue_error_type; 51 break; 52 case MCE_ERROR_TYPE_SLB: 53 mce->u.slb_error.slb_error_type = mce_err->u.slb_error_type; 54 break; 55 case MCE_ERROR_TYPE_ERAT: 56 mce->u.erat_error.erat_error_type = mce_err->u.erat_error_type; 57 break; 58 case MCE_ERROR_TYPE_TLB: 59 mce->u.tlb_error.tlb_error_type = mce_err->u.tlb_error_type; 60 break; 61 case MCE_ERROR_TYPE_UNKNOWN: 62 default: 63 break; 64 } 65 } 66 67 /* 68 * Decode and save high level MCE information into per cpu buffer which 69 * is an array of machine_check_event structure. 70 */ 71 void save_mce_event(struct pt_regs *regs, long handled, 72 struct mce_error_info *mce_err, 73 uint64_t nip, uint64_t addr) 74 { 75 uint64_t srr1; 76 int index = __this_cpu_inc_return(mce_nest_count) - 1; 77 struct machine_check_event *mce = this_cpu_ptr(&mce_event[index]); 78 79 /* 80 * Return if we don't have enough space to log mce event. 81 * mce_nest_count may go beyond MAX_MC_EVT but that's ok, 82 * the check below will stop buffer overrun. 83 */ 84 if (index >= MAX_MC_EVT) 85 return; 86 87 /* Populate generic machine check info */ 88 mce->version = MCE_V1; 89 mce->srr0 = nip; 90 mce->srr1 = regs->msr; 91 mce->gpr3 = regs->gpr[3]; 92 mce->in_use = 1; 93 94 mce->initiator = MCE_INITIATOR_CPU; 95 if (handled) 96 mce->disposition = MCE_DISPOSITION_RECOVERED; 97 else 98 mce->disposition = MCE_DISPOSITION_NOT_RECOVERED; 99 mce->severity = MCE_SEV_ERROR_SYNC; 100 101 srr1 = regs->msr; 102 103 /* 104 * Populate the mce error_type and type-specific error_type. 105 */ 106 mce_set_error_info(mce, mce_err); 107 108 if (!addr) 109 return; 110 111 if (mce->error_type == MCE_ERROR_TYPE_TLB) { 112 mce->u.tlb_error.effective_address_provided = true; 113 mce->u.tlb_error.effective_address = addr; 114 } else if (mce->error_type == MCE_ERROR_TYPE_SLB) { 115 mce->u.slb_error.effective_address_provided = true; 116 mce->u.slb_error.effective_address = addr; 117 } else if (mce->error_type == MCE_ERROR_TYPE_ERAT) { 118 mce->u.erat_error.effective_address_provided = true; 119 mce->u.erat_error.effective_address = addr; 120 } else if (mce->error_type == MCE_ERROR_TYPE_UE) { 121 mce->u.ue_error.effective_address_provided = true; 122 mce->u.ue_error.effective_address = addr; 123 } 124 return; 125 } 126 127 /* 128 * get_mce_event: 129 * mce Pointer to machine_check_event structure to be filled. 130 * release Flag to indicate whether to free the event slot or not. 131 * 0 <= do not release the mce event. Caller will invoke 132 * release_mce_event() once event has been consumed. 133 * 1 <= release the slot. 134 * 135 * return 1 = success 136 * 0 = failure 137 * 138 * get_mce_event() will be called by platform specific machine check 139 * handle routine and in KVM. 140 * When we call get_mce_event(), we are still in interrupt context and 141 * preemption will not be scheduled until ret_from_expect() routine 142 * is called. 143 */ 144 int get_mce_event(struct machine_check_event *mce, bool release) 145 { 146 int index = __this_cpu_read(mce_nest_count) - 1; 147 struct machine_check_event *mc_evt; 148 int ret = 0; 149 150 /* Sanity check */ 151 if (index < 0) 152 return ret; 153 154 /* Check if we have MCE info to process. */ 155 if (index < MAX_MC_EVT) { 156 mc_evt = this_cpu_ptr(&mce_event[index]); 157 /* Copy the event structure and release the original */ 158 if (mce) 159 *mce = *mc_evt; 160 if (release) 161 mc_evt->in_use = 0; 162 ret = 1; 163 } 164 /* Decrement the count to free the slot. */ 165 if (release) 166 __this_cpu_dec(mce_nest_count); 167 168 return ret; 169 } 170 171 void release_mce_event(void) 172 { 173 get_mce_event(NULL, true); 174 } 175 176 /* 177 * Queue up the MCE event which then can be handled later. 178 */ 179 void machine_check_queue_event(void) 180 { 181 int index; 182 struct machine_check_event evt; 183 184 if (!get_mce_event(&evt, MCE_EVENT_RELEASE)) 185 return; 186 187 index = __this_cpu_inc_return(mce_queue_count) - 1; 188 /* If queue is full, just return for now. */ 189 if (index >= MAX_MC_EVT) { 190 __this_cpu_dec(mce_queue_count); 191 return; 192 } 193 memcpy(this_cpu_ptr(&mce_event_queue[index]), &evt, sizeof(evt)); 194 195 /* Queue irq work to process this event later. */ 196 irq_work_queue(&mce_event_process_work); 197 } 198 199 /* 200 * process pending MCE event from the mce event queue. This function will be 201 * called during syscall exit. 202 */ 203 static void machine_check_process_queued_event(struct irq_work *work) 204 { 205 int index; 206 207 /* 208 * For now just print it to console. 209 * TODO: log this error event to FSP or nvram. 210 */ 211 while (__this_cpu_read(mce_queue_count) > 0) { 212 index = __this_cpu_read(mce_queue_count) - 1; 213 machine_check_print_event_info( 214 this_cpu_ptr(&mce_event_queue[index])); 215 __this_cpu_dec(mce_queue_count); 216 } 217 } 218 219 void machine_check_print_event_info(struct machine_check_event *evt) 220 { 221 const char *level, *sevstr, *subtype; 222 static const char *mc_ue_types[] = { 223 "Indeterminate", 224 "Instruction fetch", 225 "Page table walk ifetch", 226 "Load/Store", 227 "Page table walk Load/Store", 228 }; 229 static const char *mc_slb_types[] = { 230 "Indeterminate", 231 "Parity", 232 "Multihit", 233 }; 234 static const char *mc_erat_types[] = { 235 "Indeterminate", 236 "Parity", 237 "Multihit", 238 }; 239 static const char *mc_tlb_types[] = { 240 "Indeterminate", 241 "Parity", 242 "Multihit", 243 }; 244 245 /* Print things out */ 246 if (evt->version != MCE_V1) { 247 pr_err("Machine Check Exception, Unknown event version %d !\n", 248 evt->version); 249 return; 250 } 251 switch (evt->severity) { 252 case MCE_SEV_NO_ERROR: 253 level = KERN_INFO; 254 sevstr = "Harmless"; 255 break; 256 case MCE_SEV_WARNING: 257 level = KERN_WARNING; 258 sevstr = ""; 259 break; 260 case MCE_SEV_ERROR_SYNC: 261 level = KERN_ERR; 262 sevstr = "Severe"; 263 break; 264 case MCE_SEV_FATAL: 265 default: 266 level = KERN_ERR; 267 sevstr = "Fatal"; 268 break; 269 } 270 271 printk("%s%s Machine check interrupt [%s]\n", level, sevstr, 272 evt->disposition == MCE_DISPOSITION_RECOVERED ? 273 "Recovered" : "[Not recovered"); 274 printk("%s Initiator: %s\n", level, 275 evt->initiator == MCE_INITIATOR_CPU ? "CPU" : "Unknown"); 276 switch (evt->error_type) { 277 case MCE_ERROR_TYPE_UE: 278 subtype = evt->u.ue_error.ue_error_type < 279 ARRAY_SIZE(mc_ue_types) ? 280 mc_ue_types[evt->u.ue_error.ue_error_type] 281 : "Unknown"; 282 printk("%s Error type: UE [%s]\n", level, subtype); 283 if (evt->u.ue_error.effective_address_provided) 284 printk("%s Effective address: %016llx\n", 285 level, evt->u.ue_error.effective_address); 286 if (evt->u.ue_error.physical_address_provided) 287 printk("%s Physial address: %016llx\n", 288 level, evt->u.ue_error.physical_address); 289 break; 290 case MCE_ERROR_TYPE_SLB: 291 subtype = evt->u.slb_error.slb_error_type < 292 ARRAY_SIZE(mc_slb_types) ? 293 mc_slb_types[evt->u.slb_error.slb_error_type] 294 : "Unknown"; 295 printk("%s Error type: SLB [%s]\n", level, subtype); 296 if (evt->u.slb_error.effective_address_provided) 297 printk("%s Effective address: %016llx\n", 298 level, evt->u.slb_error.effective_address); 299 break; 300 case MCE_ERROR_TYPE_ERAT: 301 subtype = evt->u.erat_error.erat_error_type < 302 ARRAY_SIZE(mc_erat_types) ? 303 mc_erat_types[evt->u.erat_error.erat_error_type] 304 : "Unknown"; 305 printk("%s Error type: ERAT [%s]\n", level, subtype); 306 if (evt->u.erat_error.effective_address_provided) 307 printk("%s Effective address: %016llx\n", 308 level, evt->u.erat_error.effective_address); 309 break; 310 case MCE_ERROR_TYPE_TLB: 311 subtype = evt->u.tlb_error.tlb_error_type < 312 ARRAY_SIZE(mc_tlb_types) ? 313 mc_tlb_types[evt->u.tlb_error.tlb_error_type] 314 : "Unknown"; 315 printk("%s Error type: TLB [%s]\n", level, subtype); 316 if (evt->u.tlb_error.effective_address_provided) 317 printk("%s Effective address: %016llx\n", 318 level, evt->u.tlb_error.effective_address); 319 break; 320 default: 321 case MCE_ERROR_TYPE_UNKNOWN: 322 printk("%s Error type: Unknown\n", level); 323 break; 324 } 325 } 326 327 uint64_t get_mce_fault_addr(struct machine_check_event *evt) 328 { 329 switch (evt->error_type) { 330 case MCE_ERROR_TYPE_UE: 331 if (evt->u.ue_error.effective_address_provided) 332 return evt->u.ue_error.effective_address; 333 break; 334 case MCE_ERROR_TYPE_SLB: 335 if (evt->u.slb_error.effective_address_provided) 336 return evt->u.slb_error.effective_address; 337 break; 338 case MCE_ERROR_TYPE_ERAT: 339 if (evt->u.erat_error.effective_address_provided) 340 return evt->u.erat_error.effective_address; 341 break; 342 case MCE_ERROR_TYPE_TLB: 343 if (evt->u.tlb_error.effective_address_provided) 344 return evt->u.tlb_error.effective_address; 345 break; 346 default: 347 case MCE_ERROR_TYPE_UNKNOWN: 348 break; 349 } 350 return 0; 351 } 352 EXPORT_SYMBOL(get_mce_fault_addr); 353