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_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 /* Mark it recovered if we have handled it and MSR(RI=1). */ 96 if (handled && (regs->msr & MSR_RI)) 97 mce->disposition = MCE_DISPOSITION_RECOVERED; 98 else 99 mce->disposition = MCE_DISPOSITION_NOT_RECOVERED; 100 mce->severity = MCE_SEV_ERROR_SYNC; 101 102 srr1 = regs->msr; 103 104 /* 105 * Populate the mce error_type and type-specific error_type. 106 */ 107 mce_set_error_info(mce, mce_err); 108 109 if (!addr) 110 return; 111 112 if (mce->error_type == MCE_ERROR_TYPE_TLB) { 113 mce->u.tlb_error.effective_address_provided = true; 114 mce->u.tlb_error.effective_address = addr; 115 } else if (mce->error_type == MCE_ERROR_TYPE_SLB) { 116 mce->u.slb_error.effective_address_provided = true; 117 mce->u.slb_error.effective_address = addr; 118 } else if (mce->error_type == MCE_ERROR_TYPE_ERAT) { 119 mce->u.erat_error.effective_address_provided = true; 120 mce->u.erat_error.effective_address = addr; 121 } else if (mce->error_type == MCE_ERROR_TYPE_UE) { 122 mce->u.ue_error.effective_address_provided = true; 123 mce->u.ue_error.effective_address = addr; 124 } 125 return; 126 } 127 128 /* 129 * get_mce_event: 130 * mce Pointer to machine_check_event structure to be filled. 131 * release Flag to indicate whether to free the event slot or not. 132 * 0 <= do not release the mce event. Caller will invoke 133 * release_mce_event() once event has been consumed. 134 * 1 <= release the slot. 135 * 136 * return 1 = success 137 * 0 = failure 138 * 139 * get_mce_event() will be called by platform specific machine check 140 * handle routine and in KVM. 141 * When we call get_mce_event(), we are still in interrupt context and 142 * preemption will not be scheduled until ret_from_expect() routine 143 * is called. 144 */ 145 int get_mce_event(struct machine_check_event *mce, bool release) 146 { 147 int index = __this_cpu_read(mce_nest_count) - 1; 148 struct machine_check_event *mc_evt; 149 int ret = 0; 150 151 /* Sanity check */ 152 if (index < 0) 153 return ret; 154 155 /* Check if we have MCE info to process. */ 156 if (index < MAX_MC_EVT) { 157 mc_evt = this_cpu_ptr(&mce_event[index]); 158 /* Copy the event structure and release the original */ 159 if (mce) 160 *mce = *mc_evt; 161 if (release) 162 mc_evt->in_use = 0; 163 ret = 1; 164 } 165 /* Decrement the count to free the slot. */ 166 if (release) 167 __this_cpu_dec(mce_nest_count); 168 169 return ret; 170 } 171 172 void release_mce_event(void) 173 { 174 get_mce_event(NULL, true); 175 } 176 177 /* 178 * Queue up the MCE event which then can be handled later. 179 */ 180 void machine_check_queue_event(void) 181 { 182 int index; 183 struct machine_check_event evt; 184 185 if (!get_mce_event(&evt, MCE_EVENT_RELEASE)) 186 return; 187 188 index = __this_cpu_inc_return(mce_queue_count) - 1; 189 /* If queue is full, just return for now. */ 190 if (index >= MAX_MC_EVT) { 191 __this_cpu_dec(mce_queue_count); 192 return; 193 } 194 memcpy(this_cpu_ptr(&mce_event_queue[index]), &evt, sizeof(evt)); 195 196 /* Queue irq work to process this event later. */ 197 irq_work_queue(&mce_event_process_work); 198 } 199 200 /* 201 * process pending MCE event from the mce event queue. This function will be 202 * called during syscall exit. 203 */ 204 static void machine_check_process_queued_event(struct irq_work *work) 205 { 206 int index; 207 208 /* 209 * For now just print it to console. 210 * TODO: log this error event to FSP or nvram. 211 */ 212 while (__this_cpu_read(mce_queue_count) > 0) { 213 index = __this_cpu_read(mce_queue_count) - 1; 214 machine_check_print_event_info( 215 this_cpu_ptr(&mce_event_queue[index])); 216 __this_cpu_dec(mce_queue_count); 217 } 218 } 219 220 void machine_check_print_event_info(struct machine_check_event *evt) 221 { 222 const char *level, *sevstr, *subtype; 223 static const char *mc_ue_types[] = { 224 "Indeterminate", 225 "Instruction fetch", 226 "Page table walk ifetch", 227 "Load/Store", 228 "Page table walk Load/Store", 229 }; 230 static const char *mc_slb_types[] = { 231 "Indeterminate", 232 "Parity", 233 "Multihit", 234 }; 235 static const char *mc_erat_types[] = { 236 "Indeterminate", 237 "Parity", 238 "Multihit", 239 }; 240 static const char *mc_tlb_types[] = { 241 "Indeterminate", 242 "Parity", 243 "Multihit", 244 }; 245 246 /* Print things out */ 247 if (evt->version != MCE_V1) { 248 pr_err("Machine Check Exception, Unknown event version %d !\n", 249 evt->version); 250 return; 251 } 252 switch (evt->severity) { 253 case MCE_SEV_NO_ERROR: 254 level = KERN_INFO; 255 sevstr = "Harmless"; 256 break; 257 case MCE_SEV_WARNING: 258 level = KERN_WARNING; 259 sevstr = ""; 260 break; 261 case MCE_SEV_ERROR_SYNC: 262 level = KERN_ERR; 263 sevstr = "Severe"; 264 break; 265 case MCE_SEV_FATAL: 266 default: 267 level = KERN_ERR; 268 sevstr = "Fatal"; 269 break; 270 } 271 272 printk("%s%s Machine check interrupt [%s]\n", level, sevstr, 273 evt->disposition == MCE_DISPOSITION_RECOVERED ? 274 "Recovered" : "[Not recovered"); 275 printk("%s Initiator: %s\n", level, 276 evt->initiator == MCE_INITIATOR_CPU ? "CPU" : "Unknown"); 277 switch (evt->error_type) { 278 case MCE_ERROR_TYPE_UE: 279 subtype = evt->u.ue_error.ue_error_type < 280 ARRAY_SIZE(mc_ue_types) ? 281 mc_ue_types[evt->u.ue_error.ue_error_type] 282 : "Unknown"; 283 printk("%s Error type: UE [%s]\n", level, subtype); 284 if (evt->u.ue_error.effective_address_provided) 285 printk("%s Effective address: %016llx\n", 286 level, evt->u.ue_error.effective_address); 287 if (evt->u.ue_error.physical_address_provided) 288 printk("%s Physical address: %016llx\n", 289 level, evt->u.ue_error.physical_address); 290 break; 291 case MCE_ERROR_TYPE_SLB: 292 subtype = evt->u.slb_error.slb_error_type < 293 ARRAY_SIZE(mc_slb_types) ? 294 mc_slb_types[evt->u.slb_error.slb_error_type] 295 : "Unknown"; 296 printk("%s Error type: SLB [%s]\n", level, subtype); 297 if (evt->u.slb_error.effective_address_provided) 298 printk("%s Effective address: %016llx\n", 299 level, evt->u.slb_error.effective_address); 300 break; 301 case MCE_ERROR_TYPE_ERAT: 302 subtype = evt->u.erat_error.erat_error_type < 303 ARRAY_SIZE(mc_erat_types) ? 304 mc_erat_types[evt->u.erat_error.erat_error_type] 305 : "Unknown"; 306 printk("%s Error type: ERAT [%s]\n", level, subtype); 307 if (evt->u.erat_error.effective_address_provided) 308 printk("%s Effective address: %016llx\n", 309 level, evt->u.erat_error.effective_address); 310 break; 311 case MCE_ERROR_TYPE_TLB: 312 subtype = evt->u.tlb_error.tlb_error_type < 313 ARRAY_SIZE(mc_tlb_types) ? 314 mc_tlb_types[evt->u.tlb_error.tlb_error_type] 315 : "Unknown"; 316 printk("%s Error type: TLB [%s]\n", level, subtype); 317 if (evt->u.tlb_error.effective_address_provided) 318 printk("%s Effective address: %016llx\n", 319 level, evt->u.tlb_error.effective_address); 320 break; 321 default: 322 case MCE_ERROR_TYPE_UNKNOWN: 323 printk("%s Error type: Unknown\n", level); 324 break; 325 } 326 } 327 328 uint64_t get_mce_fault_addr(struct machine_check_event *evt) 329 { 330 switch (evt->error_type) { 331 case MCE_ERROR_TYPE_UE: 332 if (evt->u.ue_error.effective_address_provided) 333 return evt->u.ue_error.effective_address; 334 break; 335 case MCE_ERROR_TYPE_SLB: 336 if (evt->u.slb_error.effective_address_provided) 337 return evt->u.slb_error.effective_address; 338 break; 339 case MCE_ERROR_TYPE_ERAT: 340 if (evt->u.erat_error.effective_address_provided) 341 return evt->u.erat_error.effective_address; 342 break; 343 case MCE_ERROR_TYPE_TLB: 344 if (evt->u.tlb_error.effective_address_provided) 345 return evt->u.tlb_error.effective_address; 346 break; 347 default: 348 case MCE_ERROR_TYPE_UNKNOWN: 349 break; 350 } 351 return 0; 352 } 353 EXPORT_SYMBOL(get_mce_fault_addr); 354