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 static 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_USER: 62 mce->u.user_error.user_error_type = mce_err->u.user_error_type; 63 break; 64 case MCE_ERROR_TYPE_RA: 65 mce->u.ra_error.ra_error_type = mce_err->u.ra_error_type; 66 break; 67 case MCE_ERROR_TYPE_LINK: 68 mce->u.link_error.link_error_type = mce_err->u.link_error_type; 69 break; 70 case MCE_ERROR_TYPE_UNKNOWN: 71 default: 72 break; 73 } 74 } 75 76 /* 77 * Decode and save high level MCE information into per cpu buffer which 78 * is an array of machine_check_event structure. 79 */ 80 void save_mce_event(struct pt_regs *regs, long handled, 81 struct mce_error_info *mce_err, 82 uint64_t nip, uint64_t addr) 83 { 84 int index = __this_cpu_inc_return(mce_nest_count) - 1; 85 struct machine_check_event *mce = this_cpu_ptr(&mce_event[index]); 86 87 /* 88 * Return if we don't have enough space to log mce event. 89 * mce_nest_count may go beyond MAX_MC_EVT but that's ok, 90 * the check below will stop buffer overrun. 91 */ 92 if (index >= MAX_MC_EVT) 93 return; 94 95 /* Populate generic machine check info */ 96 mce->version = MCE_V1; 97 mce->srr0 = nip; 98 mce->srr1 = regs->msr; 99 mce->gpr3 = regs->gpr[3]; 100 mce->in_use = 1; 101 102 /* Mark it recovered if we have handled it and MSR(RI=1). */ 103 if (handled && (regs->msr & MSR_RI)) 104 mce->disposition = MCE_DISPOSITION_RECOVERED; 105 else 106 mce->disposition = MCE_DISPOSITION_NOT_RECOVERED; 107 108 mce->initiator = mce_err->initiator; 109 mce->severity = mce_err->severity; 110 111 /* 112 * Populate the mce error_type and type-specific error_type. 113 */ 114 mce_set_error_info(mce, mce_err); 115 116 if (!addr) 117 return; 118 119 if (mce->error_type == MCE_ERROR_TYPE_TLB) { 120 mce->u.tlb_error.effective_address_provided = true; 121 mce->u.tlb_error.effective_address = addr; 122 } else if (mce->error_type == MCE_ERROR_TYPE_SLB) { 123 mce->u.slb_error.effective_address_provided = true; 124 mce->u.slb_error.effective_address = addr; 125 } else if (mce->error_type == MCE_ERROR_TYPE_ERAT) { 126 mce->u.erat_error.effective_address_provided = true; 127 mce->u.erat_error.effective_address = addr; 128 } else if (mce->error_type == MCE_ERROR_TYPE_USER) { 129 mce->u.user_error.effective_address_provided = true; 130 mce->u.user_error.effective_address = addr; 131 } else if (mce->error_type == MCE_ERROR_TYPE_RA) { 132 mce->u.ra_error.effective_address_provided = true; 133 mce->u.ra_error.effective_address = addr; 134 } else if (mce->error_type == MCE_ERROR_TYPE_LINK) { 135 mce->u.link_error.effective_address_provided = true; 136 mce->u.link_error.effective_address = addr; 137 } else if (mce->error_type == MCE_ERROR_TYPE_UE) { 138 mce->u.ue_error.effective_address_provided = true; 139 mce->u.ue_error.effective_address = addr; 140 } 141 return; 142 } 143 144 /* 145 * get_mce_event: 146 * mce Pointer to machine_check_event structure to be filled. 147 * release Flag to indicate whether to free the event slot or not. 148 * 0 <= do not release the mce event. Caller will invoke 149 * release_mce_event() once event has been consumed. 150 * 1 <= release the slot. 151 * 152 * return 1 = success 153 * 0 = failure 154 * 155 * get_mce_event() will be called by platform specific machine check 156 * handle routine and in KVM. 157 * When we call get_mce_event(), we are still in interrupt context and 158 * preemption will not be scheduled until ret_from_expect() routine 159 * is called. 160 */ 161 int get_mce_event(struct machine_check_event *mce, bool release) 162 { 163 int index = __this_cpu_read(mce_nest_count) - 1; 164 struct machine_check_event *mc_evt; 165 int ret = 0; 166 167 /* Sanity check */ 168 if (index < 0) 169 return ret; 170 171 /* Check if we have MCE info to process. */ 172 if (index < MAX_MC_EVT) { 173 mc_evt = this_cpu_ptr(&mce_event[index]); 174 /* Copy the event structure and release the original */ 175 if (mce) 176 *mce = *mc_evt; 177 if (release) 178 mc_evt->in_use = 0; 179 ret = 1; 180 } 181 /* Decrement the count to free the slot. */ 182 if (release) 183 __this_cpu_dec(mce_nest_count); 184 185 return ret; 186 } 187 188 void release_mce_event(void) 189 { 190 get_mce_event(NULL, true); 191 } 192 193 /* 194 * Queue up the MCE event which then can be handled later. 195 */ 196 void machine_check_queue_event(void) 197 { 198 int index; 199 struct machine_check_event evt; 200 201 if (!get_mce_event(&evt, MCE_EVENT_RELEASE)) 202 return; 203 204 index = __this_cpu_inc_return(mce_queue_count) - 1; 205 /* If queue is full, just return for now. */ 206 if (index >= MAX_MC_EVT) { 207 __this_cpu_dec(mce_queue_count); 208 return; 209 } 210 memcpy(this_cpu_ptr(&mce_event_queue[index]), &evt, sizeof(evt)); 211 212 /* Queue irq work to process this event later. */ 213 irq_work_queue(&mce_event_process_work); 214 } 215 216 /* 217 * process pending MCE event from the mce event queue. This function will be 218 * called during syscall exit. 219 */ 220 static void machine_check_process_queued_event(struct irq_work *work) 221 { 222 int index; 223 224 add_taint(TAINT_MACHINE_CHECK, LOCKDEP_NOW_UNRELIABLE); 225 226 /* 227 * For now just print it to console. 228 * TODO: log this error event to FSP or nvram. 229 */ 230 while (__this_cpu_read(mce_queue_count) > 0) { 231 index = __this_cpu_read(mce_queue_count) - 1; 232 machine_check_print_event_info( 233 this_cpu_ptr(&mce_event_queue[index]), false); 234 __this_cpu_dec(mce_queue_count); 235 } 236 } 237 238 void machine_check_print_event_info(struct machine_check_event *evt, 239 bool user_mode) 240 { 241 const char *level, *sevstr, *subtype; 242 static const char *mc_ue_types[] = { 243 "Indeterminate", 244 "Instruction fetch", 245 "Page table walk ifetch", 246 "Load/Store", 247 "Page table walk Load/Store", 248 }; 249 static const char *mc_slb_types[] = { 250 "Indeterminate", 251 "Parity", 252 "Multihit", 253 }; 254 static const char *mc_erat_types[] = { 255 "Indeterminate", 256 "Parity", 257 "Multihit", 258 }; 259 static const char *mc_tlb_types[] = { 260 "Indeterminate", 261 "Parity", 262 "Multihit", 263 }; 264 static const char *mc_user_types[] = { 265 "Indeterminate", 266 "tlbie(l) invalid", 267 }; 268 static const char *mc_ra_types[] = { 269 "Indeterminate", 270 "Instruction fetch (bad)", 271 "Page table walk ifetch (bad)", 272 "Page table walk ifetch (foreign)", 273 "Load (bad)", 274 "Store (bad)", 275 "Page table walk Load/Store (bad)", 276 "Page table walk Load/Store (foreign)", 277 "Load/Store (foreign)", 278 }; 279 static const char *mc_link_types[] = { 280 "Indeterminate", 281 "Instruction fetch (timeout)", 282 "Page table walk ifetch (timeout)", 283 "Load (timeout)", 284 "Store (timeout)", 285 "Page table walk Load/Store (timeout)", 286 }; 287 288 /* Print things out */ 289 if (evt->version != MCE_V1) { 290 pr_err("Machine Check Exception, Unknown event version %d !\n", 291 evt->version); 292 return; 293 } 294 switch (evt->severity) { 295 case MCE_SEV_NO_ERROR: 296 level = KERN_INFO; 297 sevstr = "Harmless"; 298 break; 299 case MCE_SEV_WARNING: 300 level = KERN_WARNING; 301 sevstr = ""; 302 break; 303 case MCE_SEV_ERROR_SYNC: 304 level = KERN_ERR; 305 sevstr = "Severe"; 306 break; 307 case MCE_SEV_FATAL: 308 default: 309 level = KERN_ERR; 310 sevstr = "Fatal"; 311 break; 312 } 313 314 printk("%s%s Machine check interrupt [%s]\n", level, sevstr, 315 evt->disposition == MCE_DISPOSITION_RECOVERED ? 316 "Recovered" : "Not recovered"); 317 318 if (user_mode) { 319 printk("%s NIP: [%016llx] PID: %d Comm: %s\n", level, 320 evt->srr0, current->pid, current->comm); 321 } else { 322 printk("%s NIP [%016llx]: %pS\n", level, evt->srr0, 323 (void *)evt->srr0); 324 } 325 326 printk("%s Initiator: %s\n", level, 327 evt->initiator == MCE_INITIATOR_CPU ? "CPU" : "Unknown"); 328 switch (evt->error_type) { 329 case MCE_ERROR_TYPE_UE: 330 subtype = evt->u.ue_error.ue_error_type < 331 ARRAY_SIZE(mc_ue_types) ? 332 mc_ue_types[evt->u.ue_error.ue_error_type] 333 : "Unknown"; 334 printk("%s Error type: UE [%s]\n", level, subtype); 335 if (evt->u.ue_error.effective_address_provided) 336 printk("%s Effective address: %016llx\n", 337 level, evt->u.ue_error.effective_address); 338 if (evt->u.ue_error.physical_address_provided) 339 printk("%s Physical address: %016llx\n", 340 level, evt->u.ue_error.physical_address); 341 break; 342 case MCE_ERROR_TYPE_SLB: 343 subtype = evt->u.slb_error.slb_error_type < 344 ARRAY_SIZE(mc_slb_types) ? 345 mc_slb_types[evt->u.slb_error.slb_error_type] 346 : "Unknown"; 347 printk("%s Error type: SLB [%s]\n", level, subtype); 348 if (evt->u.slb_error.effective_address_provided) 349 printk("%s Effective address: %016llx\n", 350 level, evt->u.slb_error.effective_address); 351 break; 352 case MCE_ERROR_TYPE_ERAT: 353 subtype = evt->u.erat_error.erat_error_type < 354 ARRAY_SIZE(mc_erat_types) ? 355 mc_erat_types[evt->u.erat_error.erat_error_type] 356 : "Unknown"; 357 printk("%s Error type: ERAT [%s]\n", level, subtype); 358 if (evt->u.erat_error.effective_address_provided) 359 printk("%s Effective address: %016llx\n", 360 level, evt->u.erat_error.effective_address); 361 break; 362 case MCE_ERROR_TYPE_TLB: 363 subtype = evt->u.tlb_error.tlb_error_type < 364 ARRAY_SIZE(mc_tlb_types) ? 365 mc_tlb_types[evt->u.tlb_error.tlb_error_type] 366 : "Unknown"; 367 printk("%s Error type: TLB [%s]\n", level, subtype); 368 if (evt->u.tlb_error.effective_address_provided) 369 printk("%s Effective address: %016llx\n", 370 level, evt->u.tlb_error.effective_address); 371 break; 372 case MCE_ERROR_TYPE_USER: 373 subtype = evt->u.user_error.user_error_type < 374 ARRAY_SIZE(mc_user_types) ? 375 mc_user_types[evt->u.user_error.user_error_type] 376 : "Unknown"; 377 printk("%s Error type: User [%s]\n", level, subtype); 378 if (evt->u.user_error.effective_address_provided) 379 printk("%s Effective address: %016llx\n", 380 level, evt->u.user_error.effective_address); 381 break; 382 case MCE_ERROR_TYPE_RA: 383 subtype = evt->u.ra_error.ra_error_type < 384 ARRAY_SIZE(mc_ra_types) ? 385 mc_ra_types[evt->u.ra_error.ra_error_type] 386 : "Unknown"; 387 printk("%s Error type: Real address [%s]\n", level, subtype); 388 if (evt->u.ra_error.effective_address_provided) 389 printk("%s Effective address: %016llx\n", 390 level, evt->u.ra_error.effective_address); 391 break; 392 case MCE_ERROR_TYPE_LINK: 393 subtype = evt->u.link_error.link_error_type < 394 ARRAY_SIZE(mc_link_types) ? 395 mc_link_types[evt->u.link_error.link_error_type] 396 : "Unknown"; 397 printk("%s Error type: Link [%s]\n", level, subtype); 398 if (evt->u.link_error.effective_address_provided) 399 printk("%s Effective address: %016llx\n", 400 level, evt->u.link_error.effective_address); 401 break; 402 default: 403 case MCE_ERROR_TYPE_UNKNOWN: 404 printk("%s Error type: Unknown\n", level); 405 break; 406 } 407 } 408 409 uint64_t get_mce_fault_addr(struct machine_check_event *evt) 410 { 411 switch (evt->error_type) { 412 case MCE_ERROR_TYPE_UE: 413 if (evt->u.ue_error.effective_address_provided) 414 return evt->u.ue_error.effective_address; 415 break; 416 case MCE_ERROR_TYPE_SLB: 417 if (evt->u.slb_error.effective_address_provided) 418 return evt->u.slb_error.effective_address; 419 break; 420 case MCE_ERROR_TYPE_ERAT: 421 if (evt->u.erat_error.effective_address_provided) 422 return evt->u.erat_error.effective_address; 423 break; 424 case MCE_ERROR_TYPE_TLB: 425 if (evt->u.tlb_error.effective_address_provided) 426 return evt->u.tlb_error.effective_address; 427 break; 428 case MCE_ERROR_TYPE_USER: 429 if (evt->u.user_error.effective_address_provided) 430 return evt->u.user_error.effective_address; 431 break; 432 case MCE_ERROR_TYPE_RA: 433 if (evt->u.ra_error.effective_address_provided) 434 return evt->u.ra_error.effective_address; 435 break; 436 case MCE_ERROR_TYPE_LINK: 437 if (evt->u.link_error.effective_address_provided) 438 return evt->u.link_error.effective_address; 439 break; 440 default: 441 case MCE_ERROR_TYPE_UNKNOWN: 442 break; 443 } 444 return 0; 445 } 446 EXPORT_SYMBOL(get_mce_fault_addr); 447