1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Machine check handler. 4 * 5 * K8 parts Copyright 2002,2003 Andi Kleen, SuSE Labs. 6 * Rest from unknown author(s). 7 * 2004 Andi Kleen. Rewrote most of it. 8 * Copyright 2008 Intel Corporation 9 * Author: Andi Kleen 10 */ 11 12 #include <linux/thread_info.h> 13 #include <linux/capability.h> 14 #include <linux/miscdevice.h> 15 #include <linux/ratelimit.h> 16 #include <linux/rcupdate.h> 17 #include <linux/kobject.h> 18 #include <linux/uaccess.h> 19 #include <linux/kdebug.h> 20 #include <linux/kernel.h> 21 #include <linux/percpu.h> 22 #include <linux/string.h> 23 #include <linux/device.h> 24 #include <linux/syscore_ops.h> 25 #include <linux/delay.h> 26 #include <linux/ctype.h> 27 #include <linux/sched.h> 28 #include <linux/sysfs.h> 29 #include <linux/types.h> 30 #include <linux/slab.h> 31 #include <linux/init.h> 32 #include <linux/kmod.h> 33 #include <linux/poll.h> 34 #include <linux/nmi.h> 35 #include <linux/cpu.h> 36 #include <linux/ras.h> 37 #include <linux/smp.h> 38 #include <linux/fs.h> 39 #include <linux/mm.h> 40 #include <linux/debugfs.h> 41 #include <linux/irq_work.h> 42 #include <linux/export.h> 43 #include <linux/jump_label.h> 44 #include <linux/set_memory.h> 45 #include <linux/task_work.h> 46 #include <linux/hardirq.h> 47 48 #include <asm/intel-family.h> 49 #include <asm/processor.h> 50 #include <asm/traps.h> 51 #include <asm/tlbflush.h> 52 #include <asm/mce.h> 53 #include <asm/msr.h> 54 #include <asm/reboot.h> 55 56 #include "internal.h" 57 58 /* sysfs synchronization */ 59 static DEFINE_MUTEX(mce_sysfs_mutex); 60 61 #define CREATE_TRACE_POINTS 62 #include <trace/events/mce.h> 63 64 #define SPINUNIT 100 /* 100ns */ 65 66 DEFINE_PER_CPU(unsigned, mce_exception_count); 67 68 DEFINE_PER_CPU_READ_MOSTLY(unsigned int, mce_num_banks); 69 70 struct mce_bank { 71 u64 ctl; /* subevents to enable */ 72 bool init; /* initialise bank? */ 73 }; 74 static DEFINE_PER_CPU_READ_MOSTLY(struct mce_bank[MAX_NR_BANKS], mce_banks_array); 75 76 #define ATTR_LEN 16 77 /* One object for each MCE bank, shared by all CPUs */ 78 struct mce_bank_dev { 79 struct device_attribute attr; /* device attribute */ 80 char attrname[ATTR_LEN]; /* attribute name */ 81 u8 bank; /* bank number */ 82 }; 83 static struct mce_bank_dev mce_bank_devs[MAX_NR_BANKS]; 84 85 struct mce_vendor_flags mce_flags __read_mostly; 86 87 struct mca_config mca_cfg __read_mostly = { 88 .bootlog = -1, 89 /* 90 * Tolerant levels: 91 * 0: always panic on uncorrected errors, log corrected errors 92 * 1: panic or SIGBUS on uncorrected errors, log corrected errors 93 * 2: SIGBUS or log uncorrected errors (if possible), log corr. errors 94 * 3: never panic or SIGBUS, log all errors (for testing only) 95 */ 96 .tolerant = 1, 97 .monarch_timeout = -1 98 }; 99 100 static DEFINE_PER_CPU(struct mce, mces_seen); 101 static unsigned long mce_need_notify; 102 static int cpu_missing; 103 104 /* 105 * MCA banks polled by the period polling timer for corrected events. 106 * With Intel CMCI, this only has MCA banks which do not support CMCI (if any). 107 */ 108 DEFINE_PER_CPU(mce_banks_t, mce_poll_banks) = { 109 [0 ... BITS_TO_LONGS(MAX_NR_BANKS)-1] = ~0UL 110 }; 111 112 /* 113 * MCA banks controlled through firmware first for corrected errors. 114 * This is a global list of banks for which we won't enable CMCI and we 115 * won't poll. Firmware controls these banks and is responsible for 116 * reporting corrected errors through GHES. Uncorrected/recoverable 117 * errors are still notified through a machine check. 118 */ 119 mce_banks_t mce_banks_ce_disabled; 120 121 static struct work_struct mce_work; 122 static struct irq_work mce_irq_work; 123 124 static void (*quirk_no_way_out)(int bank, struct mce *m, struct pt_regs *regs); 125 126 /* 127 * CPU/chipset specific EDAC code can register a notifier call here to print 128 * MCE errors in a human-readable form. 129 */ 130 BLOCKING_NOTIFIER_HEAD(x86_mce_decoder_chain); 131 132 /* Do initial initialization of a struct mce */ 133 noinstr void mce_setup(struct mce *m) 134 { 135 memset(m, 0, sizeof(struct mce)); 136 m->cpu = m->extcpu = smp_processor_id(); 137 /* need the internal __ version to avoid deadlocks */ 138 m->time = __ktime_get_real_seconds(); 139 m->cpuvendor = boot_cpu_data.x86_vendor; 140 m->cpuid = cpuid_eax(1); 141 m->socketid = cpu_data(m->extcpu).phys_proc_id; 142 m->apicid = cpu_data(m->extcpu).initial_apicid; 143 m->mcgcap = __rdmsr(MSR_IA32_MCG_CAP); 144 145 if (this_cpu_has(X86_FEATURE_INTEL_PPIN)) 146 m->ppin = __rdmsr(MSR_PPIN); 147 else if (this_cpu_has(X86_FEATURE_AMD_PPIN)) 148 m->ppin = __rdmsr(MSR_AMD_PPIN); 149 150 m->microcode = boot_cpu_data.microcode; 151 } 152 153 DEFINE_PER_CPU(struct mce, injectm); 154 EXPORT_PER_CPU_SYMBOL_GPL(injectm); 155 156 void mce_log(struct mce *m) 157 { 158 if (!mce_gen_pool_add(m)) 159 irq_work_queue(&mce_irq_work); 160 } 161 EXPORT_SYMBOL_GPL(mce_log); 162 163 void mce_register_decode_chain(struct notifier_block *nb) 164 { 165 if (WARN_ON(nb->priority > MCE_PRIO_MCELOG && nb->priority < MCE_PRIO_EDAC)) 166 return; 167 168 blocking_notifier_chain_register(&x86_mce_decoder_chain, nb); 169 } 170 EXPORT_SYMBOL_GPL(mce_register_decode_chain); 171 172 void mce_unregister_decode_chain(struct notifier_block *nb) 173 { 174 blocking_notifier_chain_unregister(&x86_mce_decoder_chain, nb); 175 } 176 EXPORT_SYMBOL_GPL(mce_unregister_decode_chain); 177 178 static inline u32 ctl_reg(int bank) 179 { 180 return MSR_IA32_MCx_CTL(bank); 181 } 182 183 static inline u32 status_reg(int bank) 184 { 185 return MSR_IA32_MCx_STATUS(bank); 186 } 187 188 static inline u32 addr_reg(int bank) 189 { 190 return MSR_IA32_MCx_ADDR(bank); 191 } 192 193 static inline u32 misc_reg(int bank) 194 { 195 return MSR_IA32_MCx_MISC(bank); 196 } 197 198 static inline u32 smca_ctl_reg(int bank) 199 { 200 return MSR_AMD64_SMCA_MCx_CTL(bank); 201 } 202 203 static inline u32 smca_status_reg(int bank) 204 { 205 return MSR_AMD64_SMCA_MCx_STATUS(bank); 206 } 207 208 static inline u32 smca_addr_reg(int bank) 209 { 210 return MSR_AMD64_SMCA_MCx_ADDR(bank); 211 } 212 213 static inline u32 smca_misc_reg(int bank) 214 { 215 return MSR_AMD64_SMCA_MCx_MISC(bank); 216 } 217 218 struct mca_msr_regs msr_ops = { 219 .ctl = ctl_reg, 220 .status = status_reg, 221 .addr = addr_reg, 222 .misc = misc_reg 223 }; 224 225 static void __print_mce(struct mce *m) 226 { 227 pr_emerg(HW_ERR "CPU %d: Machine Check%s: %Lx Bank %d: %016Lx\n", 228 m->extcpu, 229 (m->mcgstatus & MCG_STATUS_MCIP ? " Exception" : ""), 230 m->mcgstatus, m->bank, m->status); 231 232 if (m->ip) { 233 pr_emerg(HW_ERR "RIP%s %02x:<%016Lx> ", 234 !(m->mcgstatus & MCG_STATUS_EIPV) ? " !INEXACT!" : "", 235 m->cs, m->ip); 236 237 if (m->cs == __KERNEL_CS) 238 pr_cont("{%pS}", (void *)(unsigned long)m->ip); 239 pr_cont("\n"); 240 } 241 242 pr_emerg(HW_ERR "TSC %llx ", m->tsc); 243 if (m->addr) 244 pr_cont("ADDR %llx ", m->addr); 245 if (m->misc) 246 pr_cont("MISC %llx ", m->misc); 247 248 if (mce_flags.smca) { 249 if (m->synd) 250 pr_cont("SYND %llx ", m->synd); 251 if (m->ipid) 252 pr_cont("IPID %llx ", m->ipid); 253 } 254 255 pr_cont("\n"); 256 257 /* 258 * Note this output is parsed by external tools and old fields 259 * should not be changed. 260 */ 261 pr_emerg(HW_ERR "PROCESSOR %u:%x TIME %llu SOCKET %u APIC %x microcode %x\n", 262 m->cpuvendor, m->cpuid, m->time, m->socketid, m->apicid, 263 m->microcode); 264 } 265 266 static void print_mce(struct mce *m) 267 { 268 __print_mce(m); 269 270 if (m->cpuvendor != X86_VENDOR_AMD && m->cpuvendor != X86_VENDOR_HYGON) 271 pr_emerg_ratelimited(HW_ERR "Run the above through 'mcelog --ascii'\n"); 272 } 273 274 #define PANIC_TIMEOUT 5 /* 5 seconds */ 275 276 static atomic_t mce_panicked; 277 278 static int fake_panic; 279 static atomic_t mce_fake_panicked; 280 281 /* Panic in progress. Enable interrupts and wait for final IPI */ 282 static void wait_for_panic(void) 283 { 284 long timeout = PANIC_TIMEOUT*USEC_PER_SEC; 285 286 preempt_disable(); 287 local_irq_enable(); 288 while (timeout-- > 0) 289 udelay(1); 290 if (panic_timeout == 0) 291 panic_timeout = mca_cfg.panic_timeout; 292 panic("Panicing machine check CPU died"); 293 } 294 295 static void mce_panic(const char *msg, struct mce *final, char *exp) 296 { 297 int apei_err = 0; 298 struct llist_node *pending; 299 struct mce_evt_llist *l; 300 301 if (!fake_panic) { 302 /* 303 * Make sure only one CPU runs in machine check panic 304 */ 305 if (atomic_inc_return(&mce_panicked) > 1) 306 wait_for_panic(); 307 barrier(); 308 309 bust_spinlocks(1); 310 console_verbose(); 311 } else { 312 /* Don't log too much for fake panic */ 313 if (atomic_inc_return(&mce_fake_panicked) > 1) 314 return; 315 } 316 pending = mce_gen_pool_prepare_records(); 317 /* First print corrected ones that are still unlogged */ 318 llist_for_each_entry(l, pending, llnode) { 319 struct mce *m = &l->mce; 320 if (!(m->status & MCI_STATUS_UC)) { 321 print_mce(m); 322 if (!apei_err) 323 apei_err = apei_write_mce(m); 324 } 325 } 326 /* Now print uncorrected but with the final one last */ 327 llist_for_each_entry(l, pending, llnode) { 328 struct mce *m = &l->mce; 329 if (!(m->status & MCI_STATUS_UC)) 330 continue; 331 if (!final || mce_cmp(m, final)) { 332 print_mce(m); 333 if (!apei_err) 334 apei_err = apei_write_mce(m); 335 } 336 } 337 if (final) { 338 print_mce(final); 339 if (!apei_err) 340 apei_err = apei_write_mce(final); 341 } 342 if (cpu_missing) 343 pr_emerg(HW_ERR "Some CPUs didn't answer in synchronization\n"); 344 if (exp) 345 pr_emerg(HW_ERR "Machine check: %s\n", exp); 346 if (!fake_panic) { 347 if (panic_timeout == 0) 348 panic_timeout = mca_cfg.panic_timeout; 349 panic(msg); 350 } else 351 pr_emerg(HW_ERR "Fake kernel panic: %s\n", msg); 352 } 353 354 /* Support code for software error injection */ 355 356 static int msr_to_offset(u32 msr) 357 { 358 unsigned bank = __this_cpu_read(injectm.bank); 359 360 if (msr == mca_cfg.rip_msr) 361 return offsetof(struct mce, ip); 362 if (msr == msr_ops.status(bank)) 363 return offsetof(struct mce, status); 364 if (msr == msr_ops.addr(bank)) 365 return offsetof(struct mce, addr); 366 if (msr == msr_ops.misc(bank)) 367 return offsetof(struct mce, misc); 368 if (msr == MSR_IA32_MCG_STATUS) 369 return offsetof(struct mce, mcgstatus); 370 return -1; 371 } 372 373 /* MSR access wrappers used for error injection */ 374 static u64 mce_rdmsrl(u32 msr) 375 { 376 u64 v; 377 378 if (__this_cpu_read(injectm.finished)) { 379 int offset = msr_to_offset(msr); 380 381 if (offset < 0) 382 return 0; 383 return *(u64 *)((char *)this_cpu_ptr(&injectm) + offset); 384 } 385 386 if (rdmsrl_safe(msr, &v)) { 387 WARN_ONCE(1, "mce: Unable to read MSR 0x%x!\n", msr); 388 /* 389 * Return zero in case the access faulted. This should 390 * not happen normally but can happen if the CPU does 391 * something weird, or if the code is buggy. 392 */ 393 v = 0; 394 } 395 396 return v; 397 } 398 399 static void mce_wrmsrl(u32 msr, u64 v) 400 { 401 if (__this_cpu_read(injectm.finished)) { 402 int offset = msr_to_offset(msr); 403 404 if (offset >= 0) 405 *(u64 *)((char *)this_cpu_ptr(&injectm) + offset) = v; 406 return; 407 } 408 wrmsrl(msr, v); 409 } 410 411 /* 412 * Collect all global (w.r.t. this processor) status about this machine 413 * check into our "mce" struct so that we can use it later to assess 414 * the severity of the problem as we read per-bank specific details. 415 */ 416 static inline void mce_gather_info(struct mce *m, struct pt_regs *regs) 417 { 418 mce_setup(m); 419 420 m->mcgstatus = mce_rdmsrl(MSR_IA32_MCG_STATUS); 421 if (regs) { 422 /* 423 * Get the address of the instruction at the time of 424 * the machine check error. 425 */ 426 if (m->mcgstatus & (MCG_STATUS_RIPV|MCG_STATUS_EIPV)) { 427 m->ip = regs->ip; 428 m->cs = regs->cs; 429 430 /* 431 * When in VM86 mode make the cs look like ring 3 432 * always. This is a lie, but it's better than passing 433 * the additional vm86 bit around everywhere. 434 */ 435 if (v8086_mode(regs)) 436 m->cs |= 3; 437 } 438 /* Use accurate RIP reporting if available. */ 439 if (mca_cfg.rip_msr) 440 m->ip = mce_rdmsrl(mca_cfg.rip_msr); 441 } 442 } 443 444 int mce_available(struct cpuinfo_x86 *c) 445 { 446 if (mca_cfg.disabled) 447 return 0; 448 return cpu_has(c, X86_FEATURE_MCE) && cpu_has(c, X86_FEATURE_MCA); 449 } 450 451 static void mce_schedule_work(void) 452 { 453 if (!mce_gen_pool_empty()) 454 schedule_work(&mce_work); 455 } 456 457 static void mce_irq_work_cb(struct irq_work *entry) 458 { 459 mce_schedule_work(); 460 } 461 462 /* 463 * Check if the address reported by the CPU is in a format we can parse. 464 * It would be possible to add code for most other cases, but all would 465 * be somewhat complicated (e.g. segment offset would require an instruction 466 * parser). So only support physical addresses up to page granuality for now. 467 */ 468 int mce_usable_address(struct mce *m) 469 { 470 if (!(m->status & MCI_STATUS_ADDRV)) 471 return 0; 472 473 /* Checks after this one are Intel/Zhaoxin-specific: */ 474 if (boot_cpu_data.x86_vendor != X86_VENDOR_INTEL && 475 boot_cpu_data.x86_vendor != X86_VENDOR_ZHAOXIN) 476 return 1; 477 478 if (!(m->status & MCI_STATUS_MISCV)) 479 return 0; 480 481 if (MCI_MISC_ADDR_LSB(m->misc) > PAGE_SHIFT) 482 return 0; 483 484 if (MCI_MISC_ADDR_MODE(m->misc) != MCI_MISC_ADDR_PHYS) 485 return 0; 486 487 return 1; 488 } 489 EXPORT_SYMBOL_GPL(mce_usable_address); 490 491 bool mce_is_memory_error(struct mce *m) 492 { 493 switch (m->cpuvendor) { 494 case X86_VENDOR_AMD: 495 case X86_VENDOR_HYGON: 496 return amd_mce_is_memory_error(m); 497 498 case X86_VENDOR_INTEL: 499 case X86_VENDOR_ZHAOXIN: 500 /* 501 * Intel SDM Volume 3B - 15.9.2 Compound Error Codes 502 * 503 * Bit 7 of the MCACOD field of IA32_MCi_STATUS is used for 504 * indicating a memory error. Bit 8 is used for indicating a 505 * cache hierarchy error. The combination of bit 2 and bit 3 506 * is used for indicating a `generic' cache hierarchy error 507 * But we can't just blindly check the above bits, because if 508 * bit 11 is set, then it is a bus/interconnect error - and 509 * either way the above bits just gives more detail on what 510 * bus/interconnect error happened. Note that bit 12 can be 511 * ignored, as it's the "filter" bit. 512 */ 513 return (m->status & 0xef80) == BIT(7) || 514 (m->status & 0xef00) == BIT(8) || 515 (m->status & 0xeffc) == 0xc; 516 517 default: 518 return false; 519 } 520 } 521 EXPORT_SYMBOL_GPL(mce_is_memory_error); 522 523 static bool whole_page(struct mce *m) 524 { 525 if (!mca_cfg.ser || !(m->status & MCI_STATUS_MISCV)) 526 return true; 527 528 return MCI_MISC_ADDR_LSB(m->misc) >= PAGE_SHIFT; 529 } 530 531 bool mce_is_correctable(struct mce *m) 532 { 533 if (m->cpuvendor == X86_VENDOR_AMD && m->status & MCI_STATUS_DEFERRED) 534 return false; 535 536 if (m->cpuvendor == X86_VENDOR_HYGON && m->status & MCI_STATUS_DEFERRED) 537 return false; 538 539 if (m->status & MCI_STATUS_UC) 540 return false; 541 542 return true; 543 } 544 EXPORT_SYMBOL_GPL(mce_is_correctable); 545 546 static int mce_early_notifier(struct notifier_block *nb, unsigned long val, 547 void *data) 548 { 549 struct mce *m = (struct mce *)data; 550 551 if (!m) 552 return NOTIFY_DONE; 553 554 /* Emit the trace record: */ 555 trace_mce_record(m); 556 557 set_bit(0, &mce_need_notify); 558 559 mce_notify_irq(); 560 561 return NOTIFY_DONE; 562 } 563 564 static struct notifier_block early_nb = { 565 .notifier_call = mce_early_notifier, 566 .priority = MCE_PRIO_EARLY, 567 }; 568 569 static int uc_decode_notifier(struct notifier_block *nb, unsigned long val, 570 void *data) 571 { 572 struct mce *mce = (struct mce *)data; 573 unsigned long pfn; 574 575 if (!mce || !mce_usable_address(mce)) 576 return NOTIFY_DONE; 577 578 if (mce->severity != MCE_AO_SEVERITY && 579 mce->severity != MCE_DEFERRED_SEVERITY) 580 return NOTIFY_DONE; 581 582 pfn = mce->addr >> PAGE_SHIFT; 583 if (!memory_failure(pfn, 0)) { 584 set_mce_nospec(pfn, whole_page(mce)); 585 mce->kflags |= MCE_HANDLED_UC; 586 } 587 588 return NOTIFY_OK; 589 } 590 591 static struct notifier_block mce_uc_nb = { 592 .notifier_call = uc_decode_notifier, 593 .priority = MCE_PRIO_UC, 594 }; 595 596 static int mce_default_notifier(struct notifier_block *nb, unsigned long val, 597 void *data) 598 { 599 struct mce *m = (struct mce *)data; 600 601 if (!m) 602 return NOTIFY_DONE; 603 604 if (mca_cfg.print_all || !m->kflags) 605 __print_mce(m); 606 607 return NOTIFY_DONE; 608 } 609 610 static struct notifier_block mce_default_nb = { 611 .notifier_call = mce_default_notifier, 612 /* lowest prio, we want it to run last. */ 613 .priority = MCE_PRIO_LOWEST, 614 }; 615 616 /* 617 * Read ADDR and MISC registers. 618 */ 619 static void mce_read_aux(struct mce *m, int i) 620 { 621 if (m->status & MCI_STATUS_MISCV) 622 m->misc = mce_rdmsrl(msr_ops.misc(i)); 623 624 if (m->status & MCI_STATUS_ADDRV) { 625 m->addr = mce_rdmsrl(msr_ops.addr(i)); 626 627 /* 628 * Mask the reported address by the reported granularity. 629 */ 630 if (mca_cfg.ser && (m->status & MCI_STATUS_MISCV)) { 631 u8 shift = MCI_MISC_ADDR_LSB(m->misc); 632 m->addr >>= shift; 633 m->addr <<= shift; 634 } 635 636 /* 637 * Extract [55:<lsb>] where lsb is the least significant 638 * *valid* bit of the address bits. 639 */ 640 if (mce_flags.smca) { 641 u8 lsb = (m->addr >> 56) & 0x3f; 642 643 m->addr &= GENMASK_ULL(55, lsb); 644 } 645 } 646 647 if (mce_flags.smca) { 648 m->ipid = mce_rdmsrl(MSR_AMD64_SMCA_MCx_IPID(i)); 649 650 if (m->status & MCI_STATUS_SYNDV) 651 m->synd = mce_rdmsrl(MSR_AMD64_SMCA_MCx_SYND(i)); 652 } 653 } 654 655 DEFINE_PER_CPU(unsigned, mce_poll_count); 656 657 /* 658 * Poll for corrected events or events that happened before reset. 659 * Those are just logged through /dev/mcelog. 660 * 661 * This is executed in standard interrupt context. 662 * 663 * Note: spec recommends to panic for fatal unsignalled 664 * errors here. However this would be quite problematic -- 665 * we would need to reimplement the Monarch handling and 666 * it would mess up the exclusion between exception handler 667 * and poll handler -- * so we skip this for now. 668 * These cases should not happen anyways, or only when the CPU 669 * is already totally * confused. In this case it's likely it will 670 * not fully execute the machine check handler either. 671 */ 672 bool machine_check_poll(enum mcp_flags flags, mce_banks_t *b) 673 { 674 struct mce_bank *mce_banks = this_cpu_ptr(mce_banks_array); 675 bool error_seen = false; 676 struct mce m; 677 int i; 678 679 this_cpu_inc(mce_poll_count); 680 681 mce_gather_info(&m, NULL); 682 683 if (flags & MCP_TIMESTAMP) 684 m.tsc = rdtsc(); 685 686 for (i = 0; i < this_cpu_read(mce_num_banks); i++) { 687 if (!mce_banks[i].ctl || !test_bit(i, *b)) 688 continue; 689 690 m.misc = 0; 691 m.addr = 0; 692 m.bank = i; 693 694 barrier(); 695 m.status = mce_rdmsrl(msr_ops.status(i)); 696 697 /* If this entry is not valid, ignore it */ 698 if (!(m.status & MCI_STATUS_VAL)) 699 continue; 700 701 /* 702 * If we are logging everything (at CPU online) or this 703 * is a corrected error, then we must log it. 704 */ 705 if ((flags & MCP_UC) || !(m.status & MCI_STATUS_UC)) 706 goto log_it; 707 708 /* 709 * Newer Intel systems that support software error 710 * recovery need to make additional checks. Other 711 * CPUs should skip over uncorrected errors, but log 712 * everything else. 713 */ 714 if (!mca_cfg.ser) { 715 if (m.status & MCI_STATUS_UC) 716 continue; 717 goto log_it; 718 } 719 720 /* Log "not enabled" (speculative) errors */ 721 if (!(m.status & MCI_STATUS_EN)) 722 goto log_it; 723 724 /* 725 * Log UCNA (SDM: 15.6.3 "UCR Error Classification") 726 * UC == 1 && PCC == 0 && S == 0 727 */ 728 if (!(m.status & MCI_STATUS_PCC) && !(m.status & MCI_STATUS_S)) 729 goto log_it; 730 731 /* 732 * Skip anything else. Presumption is that our read of this 733 * bank is racing with a machine check. Leave the log alone 734 * for do_machine_check() to deal with it. 735 */ 736 continue; 737 738 log_it: 739 error_seen = true; 740 741 if (flags & MCP_DONTLOG) 742 goto clear_it; 743 744 mce_read_aux(&m, i); 745 m.severity = mce_severity(&m, mca_cfg.tolerant, NULL, false); 746 /* 747 * Don't get the IP here because it's unlikely to 748 * have anything to do with the actual error location. 749 */ 750 751 if (mca_cfg.dont_log_ce && !mce_usable_address(&m)) 752 goto clear_it; 753 754 mce_log(&m); 755 756 clear_it: 757 /* 758 * Clear state for this bank. 759 */ 760 mce_wrmsrl(msr_ops.status(i), 0); 761 } 762 763 /* 764 * Don't clear MCG_STATUS here because it's only defined for 765 * exceptions. 766 */ 767 768 sync_core(); 769 770 return error_seen; 771 } 772 EXPORT_SYMBOL_GPL(machine_check_poll); 773 774 /* 775 * Do a quick check if any of the events requires a panic. 776 * This decides if we keep the events around or clear them. 777 */ 778 static int mce_no_way_out(struct mce *m, char **msg, unsigned long *validp, 779 struct pt_regs *regs) 780 { 781 char *tmp = *msg; 782 int i; 783 784 for (i = 0; i < this_cpu_read(mce_num_banks); i++) { 785 m->status = mce_rdmsrl(msr_ops.status(i)); 786 if (!(m->status & MCI_STATUS_VAL)) 787 continue; 788 789 __set_bit(i, validp); 790 if (quirk_no_way_out) 791 quirk_no_way_out(i, m, regs); 792 793 m->bank = i; 794 if (mce_severity(m, mca_cfg.tolerant, &tmp, true) >= MCE_PANIC_SEVERITY) { 795 mce_read_aux(m, i); 796 *msg = tmp; 797 return 1; 798 } 799 } 800 return 0; 801 } 802 803 /* 804 * Variable to establish order between CPUs while scanning. 805 * Each CPU spins initially until executing is equal its number. 806 */ 807 static atomic_t mce_executing; 808 809 /* 810 * Defines order of CPUs on entry. First CPU becomes Monarch. 811 */ 812 static atomic_t mce_callin; 813 814 /* 815 * Check if a timeout waiting for other CPUs happened. 816 */ 817 static int mce_timed_out(u64 *t, const char *msg) 818 { 819 /* 820 * The others already did panic for some reason. 821 * Bail out like in a timeout. 822 * rmb() to tell the compiler that system_state 823 * might have been modified by someone else. 824 */ 825 rmb(); 826 if (atomic_read(&mce_panicked)) 827 wait_for_panic(); 828 if (!mca_cfg.monarch_timeout) 829 goto out; 830 if ((s64)*t < SPINUNIT) { 831 if (mca_cfg.tolerant <= 1) 832 mce_panic(msg, NULL, NULL); 833 cpu_missing = 1; 834 return 1; 835 } 836 *t -= SPINUNIT; 837 out: 838 touch_nmi_watchdog(); 839 return 0; 840 } 841 842 /* 843 * The Monarch's reign. The Monarch is the CPU who entered 844 * the machine check handler first. It waits for the others to 845 * raise the exception too and then grades them. When any 846 * error is fatal panic. Only then let the others continue. 847 * 848 * The other CPUs entering the MCE handler will be controlled by the 849 * Monarch. They are called Subjects. 850 * 851 * This way we prevent any potential data corruption in a unrecoverable case 852 * and also makes sure always all CPU's errors are examined. 853 * 854 * Also this detects the case of a machine check event coming from outer 855 * space (not detected by any CPUs) In this case some external agent wants 856 * us to shut down, so panic too. 857 * 858 * The other CPUs might still decide to panic if the handler happens 859 * in a unrecoverable place, but in this case the system is in a semi-stable 860 * state and won't corrupt anything by itself. It's ok to let the others 861 * continue for a bit first. 862 * 863 * All the spin loops have timeouts; when a timeout happens a CPU 864 * typically elects itself to be Monarch. 865 */ 866 static void mce_reign(void) 867 { 868 int cpu; 869 struct mce *m = NULL; 870 int global_worst = 0; 871 char *msg = NULL; 872 char *nmsg = NULL; 873 874 /* 875 * This CPU is the Monarch and the other CPUs have run 876 * through their handlers. 877 * Grade the severity of the errors of all the CPUs. 878 */ 879 for_each_possible_cpu(cpu) { 880 int severity = mce_severity(&per_cpu(mces_seen, cpu), 881 mca_cfg.tolerant, 882 &nmsg, true); 883 if (severity > global_worst) { 884 msg = nmsg; 885 global_worst = severity; 886 m = &per_cpu(mces_seen, cpu); 887 } 888 } 889 890 /* 891 * Cannot recover? Panic here then. 892 * This dumps all the mces in the log buffer and stops the 893 * other CPUs. 894 */ 895 if (m && global_worst >= MCE_PANIC_SEVERITY && mca_cfg.tolerant < 3) 896 mce_panic("Fatal machine check", m, msg); 897 898 /* 899 * For UC somewhere we let the CPU who detects it handle it. 900 * Also must let continue the others, otherwise the handling 901 * CPU could deadlock on a lock. 902 */ 903 904 /* 905 * No machine check event found. Must be some external 906 * source or one CPU is hung. Panic. 907 */ 908 if (global_worst <= MCE_KEEP_SEVERITY && mca_cfg.tolerant < 3) 909 mce_panic("Fatal machine check from unknown source", NULL, NULL); 910 911 /* 912 * Now clear all the mces_seen so that they don't reappear on 913 * the next mce. 914 */ 915 for_each_possible_cpu(cpu) 916 memset(&per_cpu(mces_seen, cpu), 0, sizeof(struct mce)); 917 } 918 919 static atomic_t global_nwo; 920 921 /* 922 * Start of Monarch synchronization. This waits until all CPUs have 923 * entered the exception handler and then determines if any of them 924 * saw a fatal event that requires panic. Then it executes them 925 * in the entry order. 926 * TBD double check parallel CPU hotunplug 927 */ 928 static int mce_start(int *no_way_out) 929 { 930 int order; 931 int cpus = num_online_cpus(); 932 u64 timeout = (u64)mca_cfg.monarch_timeout * NSEC_PER_USEC; 933 934 if (!timeout) 935 return -1; 936 937 atomic_add(*no_way_out, &global_nwo); 938 /* 939 * Rely on the implied barrier below, such that global_nwo 940 * is updated before mce_callin. 941 */ 942 order = atomic_inc_return(&mce_callin); 943 944 /* 945 * Wait for everyone. 946 */ 947 while (atomic_read(&mce_callin) != cpus) { 948 if (mce_timed_out(&timeout, 949 "Timeout: Not all CPUs entered broadcast exception handler")) { 950 atomic_set(&global_nwo, 0); 951 return -1; 952 } 953 ndelay(SPINUNIT); 954 } 955 956 /* 957 * mce_callin should be read before global_nwo 958 */ 959 smp_rmb(); 960 961 if (order == 1) { 962 /* 963 * Monarch: Starts executing now, the others wait. 964 */ 965 atomic_set(&mce_executing, 1); 966 } else { 967 /* 968 * Subject: Now start the scanning loop one by one in 969 * the original callin order. 970 * This way when there are any shared banks it will be 971 * only seen by one CPU before cleared, avoiding duplicates. 972 */ 973 while (atomic_read(&mce_executing) < order) { 974 if (mce_timed_out(&timeout, 975 "Timeout: Subject CPUs unable to finish machine check processing")) { 976 atomic_set(&global_nwo, 0); 977 return -1; 978 } 979 ndelay(SPINUNIT); 980 } 981 } 982 983 /* 984 * Cache the global no_way_out state. 985 */ 986 *no_way_out = atomic_read(&global_nwo); 987 988 return order; 989 } 990 991 /* 992 * Synchronize between CPUs after main scanning loop. 993 * This invokes the bulk of the Monarch processing. 994 */ 995 static int mce_end(int order) 996 { 997 int ret = -1; 998 u64 timeout = (u64)mca_cfg.monarch_timeout * NSEC_PER_USEC; 999 1000 if (!timeout) 1001 goto reset; 1002 if (order < 0) 1003 goto reset; 1004 1005 /* 1006 * Allow others to run. 1007 */ 1008 atomic_inc(&mce_executing); 1009 1010 if (order == 1) { 1011 /* CHECKME: Can this race with a parallel hotplug? */ 1012 int cpus = num_online_cpus(); 1013 1014 /* 1015 * Monarch: Wait for everyone to go through their scanning 1016 * loops. 1017 */ 1018 while (atomic_read(&mce_executing) <= cpus) { 1019 if (mce_timed_out(&timeout, 1020 "Timeout: Monarch CPU unable to finish machine check processing")) 1021 goto reset; 1022 ndelay(SPINUNIT); 1023 } 1024 1025 mce_reign(); 1026 barrier(); 1027 ret = 0; 1028 } else { 1029 /* 1030 * Subject: Wait for Monarch to finish. 1031 */ 1032 while (atomic_read(&mce_executing) != 0) { 1033 if (mce_timed_out(&timeout, 1034 "Timeout: Monarch CPU did not finish machine check processing")) 1035 goto reset; 1036 ndelay(SPINUNIT); 1037 } 1038 1039 /* 1040 * Don't reset anything. That's done by the Monarch. 1041 */ 1042 return 0; 1043 } 1044 1045 /* 1046 * Reset all global state. 1047 */ 1048 reset: 1049 atomic_set(&global_nwo, 0); 1050 atomic_set(&mce_callin, 0); 1051 barrier(); 1052 1053 /* 1054 * Let others run again. 1055 */ 1056 atomic_set(&mce_executing, 0); 1057 return ret; 1058 } 1059 1060 static void mce_clear_state(unsigned long *toclear) 1061 { 1062 int i; 1063 1064 for (i = 0; i < this_cpu_read(mce_num_banks); i++) { 1065 if (test_bit(i, toclear)) 1066 mce_wrmsrl(msr_ops.status(i), 0); 1067 } 1068 } 1069 1070 /* 1071 * Cases where we avoid rendezvous handler timeout: 1072 * 1) If this CPU is offline. 1073 * 1074 * 2) If crashing_cpu was set, e.g. we're entering kdump and we need to 1075 * skip those CPUs which remain looping in the 1st kernel - see 1076 * crash_nmi_callback(). 1077 * 1078 * Note: there still is a small window between kexec-ing and the new, 1079 * kdump kernel establishing a new #MC handler where a broadcasted MCE 1080 * might not get handled properly. 1081 */ 1082 static noinstr bool mce_check_crashing_cpu(void) 1083 { 1084 unsigned int cpu = smp_processor_id(); 1085 1086 if (cpu_is_offline(cpu) || 1087 (crashing_cpu != -1 && crashing_cpu != cpu)) { 1088 u64 mcgstatus; 1089 1090 mcgstatus = __rdmsr(MSR_IA32_MCG_STATUS); 1091 1092 if (boot_cpu_data.x86_vendor == X86_VENDOR_ZHAOXIN) { 1093 if (mcgstatus & MCG_STATUS_LMCES) 1094 return false; 1095 } 1096 1097 if (mcgstatus & MCG_STATUS_RIPV) { 1098 __wrmsr(MSR_IA32_MCG_STATUS, 0, 0); 1099 return true; 1100 } 1101 } 1102 return false; 1103 } 1104 1105 static void __mc_scan_banks(struct mce *m, struct mce *final, 1106 unsigned long *toclear, unsigned long *valid_banks, 1107 int no_way_out, int *worst) 1108 { 1109 struct mce_bank *mce_banks = this_cpu_ptr(mce_banks_array); 1110 struct mca_config *cfg = &mca_cfg; 1111 int severity, i; 1112 1113 for (i = 0; i < this_cpu_read(mce_num_banks); i++) { 1114 __clear_bit(i, toclear); 1115 if (!test_bit(i, valid_banks)) 1116 continue; 1117 1118 if (!mce_banks[i].ctl) 1119 continue; 1120 1121 m->misc = 0; 1122 m->addr = 0; 1123 m->bank = i; 1124 1125 m->status = mce_rdmsrl(msr_ops.status(i)); 1126 if (!(m->status & MCI_STATUS_VAL)) 1127 continue; 1128 1129 /* 1130 * Corrected or non-signaled errors are handled by 1131 * machine_check_poll(). Leave them alone, unless this panics. 1132 */ 1133 if (!(m->status & (cfg->ser ? MCI_STATUS_S : MCI_STATUS_UC)) && 1134 !no_way_out) 1135 continue; 1136 1137 /* Set taint even when machine check was not enabled. */ 1138 add_taint(TAINT_MACHINE_CHECK, LOCKDEP_NOW_UNRELIABLE); 1139 1140 severity = mce_severity(m, cfg->tolerant, NULL, true); 1141 1142 /* 1143 * When machine check was for corrected/deferred handler don't 1144 * touch, unless we're panicking. 1145 */ 1146 if ((severity == MCE_KEEP_SEVERITY || 1147 severity == MCE_UCNA_SEVERITY) && !no_way_out) 1148 continue; 1149 1150 __set_bit(i, toclear); 1151 1152 /* Machine check event was not enabled. Clear, but ignore. */ 1153 if (severity == MCE_NO_SEVERITY) 1154 continue; 1155 1156 mce_read_aux(m, i); 1157 1158 /* assuming valid severity level != 0 */ 1159 m->severity = severity; 1160 1161 mce_log(m); 1162 1163 if (severity > *worst) { 1164 *final = *m; 1165 *worst = severity; 1166 } 1167 } 1168 1169 /* mce_clear_state will clear *final, save locally for use later */ 1170 *m = *final; 1171 } 1172 1173 static void kill_me_now(struct callback_head *ch) 1174 { 1175 force_sig(SIGBUS); 1176 } 1177 1178 static void kill_me_maybe(struct callback_head *cb) 1179 { 1180 struct task_struct *p = container_of(cb, struct task_struct, mce_kill_me); 1181 int flags = MF_ACTION_REQUIRED; 1182 1183 pr_err("Uncorrected hardware memory error in user-access at %llx", p->mce_addr); 1184 1185 if (!p->mce_ripv) 1186 flags |= MF_MUST_KILL; 1187 1188 if (!memory_failure(p->mce_addr >> PAGE_SHIFT, flags)) { 1189 set_mce_nospec(p->mce_addr >> PAGE_SHIFT, p->mce_whole_page); 1190 return; 1191 } 1192 1193 pr_err("Memory error not recovered"); 1194 kill_me_now(cb); 1195 } 1196 1197 /* 1198 * The actual machine check handler. This only handles real 1199 * exceptions when something got corrupted coming in through int 18. 1200 * 1201 * This is executed in NMI context not subject to normal locking rules. This 1202 * implies that most kernel services cannot be safely used. Don't even 1203 * think about putting a printk in there! 1204 * 1205 * On Intel systems this is entered on all CPUs in parallel through 1206 * MCE broadcast. However some CPUs might be broken beyond repair, 1207 * so be always careful when synchronizing with others. 1208 * 1209 * Tracing and kprobes are disabled: if we interrupted a kernel context 1210 * with IF=1, we need to minimize stack usage. There are also recursion 1211 * issues: if the machine check was due to a failure of the memory 1212 * backing the user stack, tracing that reads the user stack will cause 1213 * potentially infinite recursion. 1214 */ 1215 void noinstr do_machine_check(struct pt_regs *regs) 1216 { 1217 DECLARE_BITMAP(valid_banks, MAX_NR_BANKS); 1218 DECLARE_BITMAP(toclear, MAX_NR_BANKS); 1219 struct mca_config *cfg = &mca_cfg; 1220 struct mce m, *final; 1221 char *msg = NULL; 1222 int worst = 0; 1223 1224 /* 1225 * Establish sequential order between the CPUs entering the machine 1226 * check handler. 1227 */ 1228 int order = -1; 1229 1230 /* 1231 * If no_way_out gets set, there is no safe way to recover from this 1232 * MCE. If mca_cfg.tolerant is cranked up, we'll try anyway. 1233 */ 1234 int no_way_out = 0; 1235 1236 /* 1237 * If kill_it gets set, there might be a way to recover from this 1238 * error. 1239 */ 1240 int kill_it = 0; 1241 1242 /* 1243 * MCEs are always local on AMD. Same is determined by MCG_STATUS_LMCES 1244 * on Intel. 1245 */ 1246 int lmce = 1; 1247 1248 this_cpu_inc(mce_exception_count); 1249 1250 mce_gather_info(&m, regs); 1251 m.tsc = rdtsc(); 1252 1253 final = this_cpu_ptr(&mces_seen); 1254 *final = m; 1255 1256 memset(valid_banks, 0, sizeof(valid_banks)); 1257 no_way_out = mce_no_way_out(&m, &msg, valid_banks, regs); 1258 1259 barrier(); 1260 1261 /* 1262 * When no restart IP might need to kill or panic. 1263 * Assume the worst for now, but if we find the 1264 * severity is MCE_AR_SEVERITY we have other options. 1265 */ 1266 if (!(m.mcgstatus & MCG_STATUS_RIPV)) 1267 kill_it = 1; 1268 1269 /* 1270 * Check if this MCE is signaled to only this logical processor, 1271 * on Intel, Zhaoxin only. 1272 */ 1273 if (m.cpuvendor == X86_VENDOR_INTEL || 1274 m.cpuvendor == X86_VENDOR_ZHAOXIN) 1275 lmce = m.mcgstatus & MCG_STATUS_LMCES; 1276 1277 /* 1278 * Local machine check may already know that we have to panic. 1279 * Broadcast machine check begins rendezvous in mce_start() 1280 * Go through all banks in exclusion of the other CPUs. This way we 1281 * don't report duplicated events on shared banks because the first one 1282 * to see it will clear it. 1283 */ 1284 if (lmce) { 1285 if (no_way_out) 1286 mce_panic("Fatal local machine check", &m, msg); 1287 } else { 1288 order = mce_start(&no_way_out); 1289 } 1290 1291 __mc_scan_banks(&m, final, toclear, valid_banks, no_way_out, &worst); 1292 1293 if (!no_way_out) 1294 mce_clear_state(toclear); 1295 1296 /* 1297 * Do most of the synchronization with other CPUs. 1298 * When there's any problem use only local no_way_out state. 1299 */ 1300 if (!lmce) { 1301 if (mce_end(order) < 0) 1302 no_way_out = worst >= MCE_PANIC_SEVERITY; 1303 } else { 1304 /* 1305 * If there was a fatal machine check we should have 1306 * already called mce_panic earlier in this function. 1307 * Since we re-read the banks, we might have found 1308 * something new. Check again to see if we found a 1309 * fatal error. We call "mce_severity()" again to 1310 * make sure we have the right "msg". 1311 */ 1312 if (worst >= MCE_PANIC_SEVERITY && mca_cfg.tolerant < 3) { 1313 mce_severity(&m, cfg->tolerant, &msg, true); 1314 mce_panic("Local fatal machine check!", &m, msg); 1315 } 1316 } 1317 1318 /* 1319 * If tolerant is at an insane level we drop requests to kill 1320 * processes and continue even when there is no way out. 1321 */ 1322 if (cfg->tolerant == 3) 1323 kill_it = 0; 1324 else if (no_way_out) 1325 mce_panic("Fatal machine check on current CPU", &m, msg); 1326 1327 if (worst > 0) 1328 irq_work_queue(&mce_irq_work); 1329 1330 mce_wrmsrl(MSR_IA32_MCG_STATUS, 0); 1331 1332 sync_core(); 1333 1334 if (worst != MCE_AR_SEVERITY && !kill_it) 1335 return; 1336 1337 /* Fault was in user mode and we need to take some action */ 1338 if ((m.cs & 3) == 3) { 1339 /* If this triggers there is no way to recover. Die hard. */ 1340 BUG_ON(!on_thread_stack() || !user_mode(regs)); 1341 1342 current->mce_addr = m.addr; 1343 current->mce_ripv = !!(m.mcgstatus & MCG_STATUS_RIPV); 1344 current->mce_whole_page = whole_page(&m); 1345 current->mce_kill_me.func = kill_me_maybe; 1346 if (kill_it) 1347 current->mce_kill_me.func = kill_me_now; 1348 task_work_add(current, ¤t->mce_kill_me, true); 1349 } else { 1350 /* 1351 * Handle an MCE which has happened in kernel space but from 1352 * which the kernel can recover: ex_has_fault_handler() has 1353 * already verified that the rIP at which the error happened is 1354 * a rIP from which the kernel can recover (by jumping to 1355 * recovery code specified in _ASM_EXTABLE_FAULT()) and the 1356 * corresponding exception handler which would do that is the 1357 * proper one. 1358 */ 1359 if (m.kflags & MCE_IN_KERNEL_RECOV) { 1360 if (!fixup_exception(regs, X86_TRAP_MC, 0, 0)) 1361 mce_panic("Failed kernel mode recovery", &m, msg); 1362 } 1363 } 1364 } 1365 EXPORT_SYMBOL_GPL(do_machine_check); 1366 1367 #ifndef CONFIG_MEMORY_FAILURE 1368 int memory_failure(unsigned long pfn, int flags) 1369 { 1370 /* mce_severity() should not hand us an ACTION_REQUIRED error */ 1371 BUG_ON(flags & MF_ACTION_REQUIRED); 1372 pr_err("Uncorrected memory error in page 0x%lx ignored\n" 1373 "Rebuild kernel with CONFIG_MEMORY_FAILURE=y for smarter handling\n", 1374 pfn); 1375 1376 return 0; 1377 } 1378 #endif 1379 1380 /* 1381 * Periodic polling timer for "silent" machine check errors. If the 1382 * poller finds an MCE, poll 2x faster. When the poller finds no more 1383 * errors, poll 2x slower (up to check_interval seconds). 1384 */ 1385 static unsigned long check_interval = INITIAL_CHECK_INTERVAL; 1386 1387 static DEFINE_PER_CPU(unsigned long, mce_next_interval); /* in jiffies */ 1388 static DEFINE_PER_CPU(struct timer_list, mce_timer); 1389 1390 static unsigned long mce_adjust_timer_default(unsigned long interval) 1391 { 1392 return interval; 1393 } 1394 1395 static unsigned long (*mce_adjust_timer)(unsigned long interval) = mce_adjust_timer_default; 1396 1397 static void __start_timer(struct timer_list *t, unsigned long interval) 1398 { 1399 unsigned long when = jiffies + interval; 1400 unsigned long flags; 1401 1402 local_irq_save(flags); 1403 1404 if (!timer_pending(t) || time_before(when, t->expires)) 1405 mod_timer(t, round_jiffies(when)); 1406 1407 local_irq_restore(flags); 1408 } 1409 1410 static void mce_timer_fn(struct timer_list *t) 1411 { 1412 struct timer_list *cpu_t = this_cpu_ptr(&mce_timer); 1413 unsigned long iv; 1414 1415 WARN_ON(cpu_t != t); 1416 1417 iv = __this_cpu_read(mce_next_interval); 1418 1419 if (mce_available(this_cpu_ptr(&cpu_info))) { 1420 machine_check_poll(0, this_cpu_ptr(&mce_poll_banks)); 1421 1422 if (mce_intel_cmci_poll()) { 1423 iv = mce_adjust_timer(iv); 1424 goto done; 1425 } 1426 } 1427 1428 /* 1429 * Alert userspace if needed. If we logged an MCE, reduce the polling 1430 * interval, otherwise increase the polling interval. 1431 */ 1432 if (mce_notify_irq()) 1433 iv = max(iv / 2, (unsigned long) HZ/100); 1434 else 1435 iv = min(iv * 2, round_jiffies_relative(check_interval * HZ)); 1436 1437 done: 1438 __this_cpu_write(mce_next_interval, iv); 1439 __start_timer(t, iv); 1440 } 1441 1442 /* 1443 * Ensure that the timer is firing in @interval from now. 1444 */ 1445 void mce_timer_kick(unsigned long interval) 1446 { 1447 struct timer_list *t = this_cpu_ptr(&mce_timer); 1448 unsigned long iv = __this_cpu_read(mce_next_interval); 1449 1450 __start_timer(t, interval); 1451 1452 if (interval < iv) 1453 __this_cpu_write(mce_next_interval, interval); 1454 } 1455 1456 /* Must not be called in IRQ context where del_timer_sync() can deadlock */ 1457 static void mce_timer_delete_all(void) 1458 { 1459 int cpu; 1460 1461 for_each_online_cpu(cpu) 1462 del_timer_sync(&per_cpu(mce_timer, cpu)); 1463 } 1464 1465 /* 1466 * Notify the user(s) about new machine check events. 1467 * Can be called from interrupt context, but not from machine check/NMI 1468 * context. 1469 */ 1470 int mce_notify_irq(void) 1471 { 1472 /* Not more than two messages every minute */ 1473 static DEFINE_RATELIMIT_STATE(ratelimit, 60*HZ, 2); 1474 1475 if (test_and_clear_bit(0, &mce_need_notify)) { 1476 mce_work_trigger(); 1477 1478 if (__ratelimit(&ratelimit)) 1479 pr_info(HW_ERR "Machine check events logged\n"); 1480 1481 return 1; 1482 } 1483 return 0; 1484 } 1485 EXPORT_SYMBOL_GPL(mce_notify_irq); 1486 1487 static void __mcheck_cpu_mce_banks_init(void) 1488 { 1489 struct mce_bank *mce_banks = this_cpu_ptr(mce_banks_array); 1490 u8 n_banks = this_cpu_read(mce_num_banks); 1491 int i; 1492 1493 for (i = 0; i < n_banks; i++) { 1494 struct mce_bank *b = &mce_banks[i]; 1495 1496 /* 1497 * Init them all, __mcheck_cpu_apply_quirks() is going to apply 1498 * the required vendor quirks before 1499 * __mcheck_cpu_init_clear_banks() does the final bank setup. 1500 */ 1501 b->ctl = -1ULL; 1502 b->init = 1; 1503 } 1504 } 1505 1506 /* 1507 * Initialize Machine Checks for a CPU. 1508 */ 1509 static void __mcheck_cpu_cap_init(void) 1510 { 1511 u64 cap; 1512 u8 b; 1513 1514 rdmsrl(MSR_IA32_MCG_CAP, cap); 1515 1516 b = cap & MCG_BANKCNT_MASK; 1517 1518 if (b > MAX_NR_BANKS) { 1519 pr_warn("CPU%d: Using only %u machine check banks out of %u\n", 1520 smp_processor_id(), MAX_NR_BANKS, b); 1521 b = MAX_NR_BANKS; 1522 } 1523 1524 this_cpu_write(mce_num_banks, b); 1525 1526 __mcheck_cpu_mce_banks_init(); 1527 1528 /* Use accurate RIP reporting if available. */ 1529 if ((cap & MCG_EXT_P) && MCG_EXT_CNT(cap) >= 9) 1530 mca_cfg.rip_msr = MSR_IA32_MCG_EIP; 1531 1532 if (cap & MCG_SER_P) 1533 mca_cfg.ser = 1; 1534 } 1535 1536 static void __mcheck_cpu_init_generic(void) 1537 { 1538 enum mcp_flags m_fl = 0; 1539 mce_banks_t all_banks; 1540 u64 cap; 1541 1542 if (!mca_cfg.bootlog) 1543 m_fl = MCP_DONTLOG; 1544 1545 /* 1546 * Log the machine checks left over from the previous reset. 1547 */ 1548 bitmap_fill(all_banks, MAX_NR_BANKS); 1549 machine_check_poll(MCP_UC | m_fl, &all_banks); 1550 1551 cr4_set_bits(X86_CR4_MCE); 1552 1553 rdmsrl(MSR_IA32_MCG_CAP, cap); 1554 if (cap & MCG_CTL_P) 1555 wrmsr(MSR_IA32_MCG_CTL, 0xffffffff, 0xffffffff); 1556 } 1557 1558 static void __mcheck_cpu_init_clear_banks(void) 1559 { 1560 struct mce_bank *mce_banks = this_cpu_ptr(mce_banks_array); 1561 int i; 1562 1563 for (i = 0; i < this_cpu_read(mce_num_banks); i++) { 1564 struct mce_bank *b = &mce_banks[i]; 1565 1566 if (!b->init) 1567 continue; 1568 wrmsrl(msr_ops.ctl(i), b->ctl); 1569 wrmsrl(msr_ops.status(i), 0); 1570 } 1571 } 1572 1573 /* 1574 * Do a final check to see if there are any unused/RAZ banks. 1575 * 1576 * This must be done after the banks have been initialized and any quirks have 1577 * been applied. 1578 * 1579 * Do not call this from any user-initiated flows, e.g. CPU hotplug or sysfs. 1580 * Otherwise, a user who disables a bank will not be able to re-enable it 1581 * without a system reboot. 1582 */ 1583 static void __mcheck_cpu_check_banks(void) 1584 { 1585 struct mce_bank *mce_banks = this_cpu_ptr(mce_banks_array); 1586 u64 msrval; 1587 int i; 1588 1589 for (i = 0; i < this_cpu_read(mce_num_banks); i++) { 1590 struct mce_bank *b = &mce_banks[i]; 1591 1592 if (!b->init) 1593 continue; 1594 1595 rdmsrl(msr_ops.ctl(i), msrval); 1596 b->init = !!msrval; 1597 } 1598 } 1599 1600 /* 1601 * During IFU recovery Sandy Bridge -EP4S processors set the RIPV and 1602 * EIPV bits in MCG_STATUS to zero on the affected logical processor (SDM 1603 * Vol 3B Table 15-20). But this confuses both the code that determines 1604 * whether the machine check occurred in kernel or user mode, and also 1605 * the severity assessment code. Pretend that EIPV was set, and take the 1606 * ip/cs values from the pt_regs that mce_gather_info() ignored earlier. 1607 */ 1608 static void quirk_sandybridge_ifu(int bank, struct mce *m, struct pt_regs *regs) 1609 { 1610 if (bank != 0) 1611 return; 1612 if ((m->mcgstatus & (MCG_STATUS_EIPV|MCG_STATUS_RIPV)) != 0) 1613 return; 1614 if ((m->status & (MCI_STATUS_OVER|MCI_STATUS_UC| 1615 MCI_STATUS_EN|MCI_STATUS_MISCV|MCI_STATUS_ADDRV| 1616 MCI_STATUS_PCC|MCI_STATUS_S|MCI_STATUS_AR| 1617 MCACOD)) != 1618 (MCI_STATUS_UC|MCI_STATUS_EN| 1619 MCI_STATUS_MISCV|MCI_STATUS_ADDRV|MCI_STATUS_S| 1620 MCI_STATUS_AR|MCACOD_INSTR)) 1621 return; 1622 1623 m->mcgstatus |= MCG_STATUS_EIPV; 1624 m->ip = regs->ip; 1625 m->cs = regs->cs; 1626 } 1627 1628 /* Add per CPU specific workarounds here */ 1629 static int __mcheck_cpu_apply_quirks(struct cpuinfo_x86 *c) 1630 { 1631 struct mce_bank *mce_banks = this_cpu_ptr(mce_banks_array); 1632 struct mca_config *cfg = &mca_cfg; 1633 1634 if (c->x86_vendor == X86_VENDOR_UNKNOWN) { 1635 pr_info("unknown CPU type - not enabling MCE support\n"); 1636 return -EOPNOTSUPP; 1637 } 1638 1639 /* This should be disabled by the BIOS, but isn't always */ 1640 if (c->x86_vendor == X86_VENDOR_AMD) { 1641 if (c->x86 == 15 && this_cpu_read(mce_num_banks) > 4) { 1642 /* 1643 * disable GART TBL walk error reporting, which 1644 * trips off incorrectly with the IOMMU & 3ware 1645 * & Cerberus: 1646 */ 1647 clear_bit(10, (unsigned long *)&mce_banks[4].ctl); 1648 } 1649 if (c->x86 < 0x11 && cfg->bootlog < 0) { 1650 /* 1651 * Lots of broken BIOS around that don't clear them 1652 * by default and leave crap in there. Don't log: 1653 */ 1654 cfg->bootlog = 0; 1655 } 1656 /* 1657 * Various K7s with broken bank 0 around. Always disable 1658 * by default. 1659 */ 1660 if (c->x86 == 6 && this_cpu_read(mce_num_banks) > 0) 1661 mce_banks[0].ctl = 0; 1662 1663 /* 1664 * overflow_recov is supported for F15h Models 00h-0fh 1665 * even though we don't have a CPUID bit for it. 1666 */ 1667 if (c->x86 == 0x15 && c->x86_model <= 0xf) 1668 mce_flags.overflow_recov = 1; 1669 1670 } 1671 1672 if (c->x86_vendor == X86_VENDOR_INTEL) { 1673 /* 1674 * SDM documents that on family 6 bank 0 should not be written 1675 * because it aliases to another special BIOS controlled 1676 * register. 1677 * But it's not aliased anymore on model 0x1a+ 1678 * Don't ignore bank 0 completely because there could be a 1679 * valid event later, merely don't write CTL0. 1680 */ 1681 1682 if (c->x86 == 6 && c->x86_model < 0x1A && this_cpu_read(mce_num_banks) > 0) 1683 mce_banks[0].init = 0; 1684 1685 /* 1686 * All newer Intel systems support MCE broadcasting. Enable 1687 * synchronization with a one second timeout. 1688 */ 1689 if ((c->x86 > 6 || (c->x86 == 6 && c->x86_model >= 0xe)) && 1690 cfg->monarch_timeout < 0) 1691 cfg->monarch_timeout = USEC_PER_SEC; 1692 1693 /* 1694 * There are also broken BIOSes on some Pentium M and 1695 * earlier systems: 1696 */ 1697 if (c->x86 == 6 && c->x86_model <= 13 && cfg->bootlog < 0) 1698 cfg->bootlog = 0; 1699 1700 if (c->x86 == 6 && c->x86_model == 45) 1701 quirk_no_way_out = quirk_sandybridge_ifu; 1702 } 1703 1704 if (c->x86_vendor == X86_VENDOR_ZHAOXIN) { 1705 /* 1706 * All newer Zhaoxin CPUs support MCE broadcasting. Enable 1707 * synchronization with a one second timeout. 1708 */ 1709 if (c->x86 > 6 || (c->x86_model == 0x19 || c->x86_model == 0x1f)) { 1710 if (cfg->monarch_timeout < 0) 1711 cfg->monarch_timeout = USEC_PER_SEC; 1712 } 1713 } 1714 1715 if (cfg->monarch_timeout < 0) 1716 cfg->monarch_timeout = 0; 1717 if (cfg->bootlog != 0) 1718 cfg->panic_timeout = 30; 1719 1720 return 0; 1721 } 1722 1723 static int __mcheck_cpu_ancient_init(struct cpuinfo_x86 *c) 1724 { 1725 if (c->x86 != 5) 1726 return 0; 1727 1728 switch (c->x86_vendor) { 1729 case X86_VENDOR_INTEL: 1730 intel_p5_mcheck_init(c); 1731 return 1; 1732 break; 1733 case X86_VENDOR_CENTAUR: 1734 winchip_mcheck_init(c); 1735 return 1; 1736 break; 1737 default: 1738 return 0; 1739 } 1740 1741 return 0; 1742 } 1743 1744 /* 1745 * Init basic CPU features needed for early decoding of MCEs. 1746 */ 1747 static void __mcheck_cpu_init_early(struct cpuinfo_x86 *c) 1748 { 1749 if (c->x86_vendor == X86_VENDOR_AMD || c->x86_vendor == X86_VENDOR_HYGON) { 1750 mce_flags.overflow_recov = !!cpu_has(c, X86_FEATURE_OVERFLOW_RECOV); 1751 mce_flags.succor = !!cpu_has(c, X86_FEATURE_SUCCOR); 1752 mce_flags.smca = !!cpu_has(c, X86_FEATURE_SMCA); 1753 mce_flags.amd_threshold = 1; 1754 1755 if (mce_flags.smca) { 1756 msr_ops.ctl = smca_ctl_reg; 1757 msr_ops.status = smca_status_reg; 1758 msr_ops.addr = smca_addr_reg; 1759 msr_ops.misc = smca_misc_reg; 1760 } 1761 } 1762 } 1763 1764 static void mce_centaur_feature_init(struct cpuinfo_x86 *c) 1765 { 1766 struct mca_config *cfg = &mca_cfg; 1767 1768 /* 1769 * All newer Centaur CPUs support MCE broadcasting. Enable 1770 * synchronization with a one second timeout. 1771 */ 1772 if ((c->x86 == 6 && c->x86_model == 0xf && c->x86_stepping >= 0xe) || 1773 c->x86 > 6) { 1774 if (cfg->monarch_timeout < 0) 1775 cfg->monarch_timeout = USEC_PER_SEC; 1776 } 1777 } 1778 1779 static void mce_zhaoxin_feature_init(struct cpuinfo_x86 *c) 1780 { 1781 struct mce_bank *mce_banks = this_cpu_ptr(mce_banks_array); 1782 1783 /* 1784 * These CPUs have MCA bank 8 which reports only one error type called 1785 * SVAD (System View Address Decoder). The reporting of that error is 1786 * controlled by IA32_MC8.CTL.0. 1787 * 1788 * If enabled, prefetching on these CPUs will cause SVAD MCE when 1789 * virtual machines start and result in a system panic. Always disable 1790 * bank 8 SVAD error by default. 1791 */ 1792 if ((c->x86 == 7 && c->x86_model == 0x1b) || 1793 (c->x86_model == 0x19 || c->x86_model == 0x1f)) { 1794 if (this_cpu_read(mce_num_banks) > 8) 1795 mce_banks[8].ctl = 0; 1796 } 1797 1798 intel_init_cmci(); 1799 intel_init_lmce(); 1800 mce_adjust_timer = cmci_intel_adjust_timer; 1801 } 1802 1803 static void mce_zhaoxin_feature_clear(struct cpuinfo_x86 *c) 1804 { 1805 intel_clear_lmce(); 1806 } 1807 1808 static void __mcheck_cpu_init_vendor(struct cpuinfo_x86 *c) 1809 { 1810 switch (c->x86_vendor) { 1811 case X86_VENDOR_INTEL: 1812 mce_intel_feature_init(c); 1813 mce_adjust_timer = cmci_intel_adjust_timer; 1814 break; 1815 1816 case X86_VENDOR_AMD: { 1817 mce_amd_feature_init(c); 1818 break; 1819 } 1820 1821 case X86_VENDOR_HYGON: 1822 mce_hygon_feature_init(c); 1823 break; 1824 1825 case X86_VENDOR_CENTAUR: 1826 mce_centaur_feature_init(c); 1827 break; 1828 1829 case X86_VENDOR_ZHAOXIN: 1830 mce_zhaoxin_feature_init(c); 1831 break; 1832 1833 default: 1834 break; 1835 } 1836 } 1837 1838 static void __mcheck_cpu_clear_vendor(struct cpuinfo_x86 *c) 1839 { 1840 switch (c->x86_vendor) { 1841 case X86_VENDOR_INTEL: 1842 mce_intel_feature_clear(c); 1843 break; 1844 1845 case X86_VENDOR_ZHAOXIN: 1846 mce_zhaoxin_feature_clear(c); 1847 break; 1848 1849 default: 1850 break; 1851 } 1852 } 1853 1854 static void mce_start_timer(struct timer_list *t) 1855 { 1856 unsigned long iv = check_interval * HZ; 1857 1858 if (mca_cfg.ignore_ce || !iv) 1859 return; 1860 1861 this_cpu_write(mce_next_interval, iv); 1862 __start_timer(t, iv); 1863 } 1864 1865 static void __mcheck_cpu_setup_timer(void) 1866 { 1867 struct timer_list *t = this_cpu_ptr(&mce_timer); 1868 1869 timer_setup(t, mce_timer_fn, TIMER_PINNED); 1870 } 1871 1872 static void __mcheck_cpu_init_timer(void) 1873 { 1874 struct timer_list *t = this_cpu_ptr(&mce_timer); 1875 1876 timer_setup(t, mce_timer_fn, TIMER_PINNED); 1877 mce_start_timer(t); 1878 } 1879 1880 bool filter_mce(struct mce *m) 1881 { 1882 if (boot_cpu_data.x86_vendor == X86_VENDOR_AMD) 1883 return amd_filter_mce(m); 1884 if (boot_cpu_data.x86_vendor == X86_VENDOR_INTEL) 1885 return intel_filter_mce(m); 1886 1887 return false; 1888 } 1889 1890 /* Handle unconfigured int18 (should never happen) */ 1891 static noinstr void unexpected_machine_check(struct pt_regs *regs) 1892 { 1893 instrumentation_begin(); 1894 pr_err("CPU#%d: Unexpected int18 (Machine Check)\n", 1895 smp_processor_id()); 1896 instrumentation_end(); 1897 } 1898 1899 /* Call the installed machine check handler for this CPU setup. */ 1900 void (*machine_check_vector)(struct pt_regs *) = unexpected_machine_check; 1901 1902 static __always_inline void exc_machine_check_kernel(struct pt_regs *regs) 1903 { 1904 /* 1905 * Only required when from kernel mode. See 1906 * mce_check_crashing_cpu() for details. 1907 */ 1908 if (machine_check_vector == do_machine_check && 1909 mce_check_crashing_cpu()) 1910 return; 1911 1912 nmi_enter(); 1913 /* 1914 * The call targets are marked noinstr, but objtool can't figure 1915 * that out because it's an indirect call. Annotate it. 1916 */ 1917 instrumentation_begin(); 1918 trace_hardirqs_off_finish(); 1919 machine_check_vector(regs); 1920 if (regs->flags & X86_EFLAGS_IF) 1921 trace_hardirqs_on_prepare(); 1922 instrumentation_end(); 1923 nmi_exit(); 1924 } 1925 1926 static __always_inline void exc_machine_check_user(struct pt_regs *regs) 1927 { 1928 idtentry_enter_user(regs); 1929 instrumentation_begin(); 1930 machine_check_vector(regs); 1931 instrumentation_end(); 1932 idtentry_exit_user(regs); 1933 } 1934 1935 #ifdef CONFIG_X86_64 1936 /* MCE hit kernel mode */ 1937 DEFINE_IDTENTRY_MCE(exc_machine_check) 1938 { 1939 unsigned long dr7; 1940 1941 dr7 = local_db_save(); 1942 exc_machine_check_kernel(regs); 1943 local_db_restore(dr7); 1944 } 1945 1946 /* The user mode variant. */ 1947 DEFINE_IDTENTRY_MCE_USER(exc_machine_check) 1948 { 1949 unsigned long dr7; 1950 1951 dr7 = local_db_save(); 1952 exc_machine_check_user(regs); 1953 local_db_restore(dr7); 1954 } 1955 #else 1956 /* 32bit unified entry point */ 1957 DEFINE_IDTENTRY_MCE(exc_machine_check) 1958 { 1959 unsigned long dr7; 1960 1961 dr7 = local_db_save(); 1962 if (user_mode(regs)) 1963 exc_machine_check_user(regs); 1964 else 1965 exc_machine_check_kernel(regs); 1966 local_db_restore(dr7); 1967 } 1968 #endif 1969 1970 /* 1971 * Called for each booted CPU to set up machine checks. 1972 * Must be called with preempt off: 1973 */ 1974 void mcheck_cpu_init(struct cpuinfo_x86 *c) 1975 { 1976 if (mca_cfg.disabled) 1977 return; 1978 1979 if (__mcheck_cpu_ancient_init(c)) 1980 return; 1981 1982 if (!mce_available(c)) 1983 return; 1984 1985 __mcheck_cpu_cap_init(); 1986 1987 if (__mcheck_cpu_apply_quirks(c) < 0) { 1988 mca_cfg.disabled = 1; 1989 return; 1990 } 1991 1992 if (mce_gen_pool_init()) { 1993 mca_cfg.disabled = 1; 1994 pr_emerg("Couldn't allocate MCE records pool!\n"); 1995 return; 1996 } 1997 1998 machine_check_vector = do_machine_check; 1999 2000 __mcheck_cpu_init_early(c); 2001 __mcheck_cpu_init_generic(); 2002 __mcheck_cpu_init_vendor(c); 2003 __mcheck_cpu_init_clear_banks(); 2004 __mcheck_cpu_check_banks(); 2005 __mcheck_cpu_setup_timer(); 2006 } 2007 2008 /* 2009 * Called for each booted CPU to clear some machine checks opt-ins 2010 */ 2011 void mcheck_cpu_clear(struct cpuinfo_x86 *c) 2012 { 2013 if (mca_cfg.disabled) 2014 return; 2015 2016 if (!mce_available(c)) 2017 return; 2018 2019 /* 2020 * Possibly to clear general settings generic to x86 2021 * __mcheck_cpu_clear_generic(c); 2022 */ 2023 __mcheck_cpu_clear_vendor(c); 2024 2025 } 2026 2027 static void __mce_disable_bank(void *arg) 2028 { 2029 int bank = *((int *)arg); 2030 __clear_bit(bank, this_cpu_ptr(mce_poll_banks)); 2031 cmci_disable_bank(bank); 2032 } 2033 2034 void mce_disable_bank(int bank) 2035 { 2036 if (bank >= this_cpu_read(mce_num_banks)) { 2037 pr_warn(FW_BUG 2038 "Ignoring request to disable invalid MCA bank %d.\n", 2039 bank); 2040 return; 2041 } 2042 set_bit(bank, mce_banks_ce_disabled); 2043 on_each_cpu(__mce_disable_bank, &bank, 1); 2044 } 2045 2046 /* 2047 * mce=off Disables machine check 2048 * mce=no_cmci Disables CMCI 2049 * mce=no_lmce Disables LMCE 2050 * mce=dont_log_ce Clears corrected events silently, no log created for CEs. 2051 * mce=print_all Print all machine check logs to console 2052 * mce=ignore_ce Disables polling and CMCI, corrected events are not cleared. 2053 * mce=TOLERANCELEVEL[,monarchtimeout] (number, see above) 2054 * monarchtimeout is how long to wait for other CPUs on machine 2055 * check, or 0 to not wait 2056 * mce=bootlog Log MCEs from before booting. Disabled by default on AMD Fam10h 2057 and older. 2058 * mce=nobootlog Don't log MCEs from before booting. 2059 * mce=bios_cmci_threshold Don't program the CMCI threshold 2060 * mce=recovery force enable memcpy_mcsafe() 2061 */ 2062 static int __init mcheck_enable(char *str) 2063 { 2064 struct mca_config *cfg = &mca_cfg; 2065 2066 if (*str == 0) { 2067 enable_p5_mce(); 2068 return 1; 2069 } 2070 if (*str == '=') 2071 str++; 2072 if (!strcmp(str, "off")) 2073 cfg->disabled = 1; 2074 else if (!strcmp(str, "no_cmci")) 2075 cfg->cmci_disabled = true; 2076 else if (!strcmp(str, "no_lmce")) 2077 cfg->lmce_disabled = 1; 2078 else if (!strcmp(str, "dont_log_ce")) 2079 cfg->dont_log_ce = true; 2080 else if (!strcmp(str, "print_all")) 2081 cfg->print_all = true; 2082 else if (!strcmp(str, "ignore_ce")) 2083 cfg->ignore_ce = true; 2084 else if (!strcmp(str, "bootlog") || !strcmp(str, "nobootlog")) 2085 cfg->bootlog = (str[0] == 'b'); 2086 else if (!strcmp(str, "bios_cmci_threshold")) 2087 cfg->bios_cmci_threshold = 1; 2088 else if (!strcmp(str, "recovery")) 2089 cfg->recovery = 1; 2090 else if (isdigit(str[0])) { 2091 if (get_option(&str, &cfg->tolerant) == 2) 2092 get_option(&str, &(cfg->monarch_timeout)); 2093 } else { 2094 pr_info("mce argument %s ignored. Please use /sys\n", str); 2095 return 0; 2096 } 2097 return 1; 2098 } 2099 __setup("mce", mcheck_enable); 2100 2101 int __init mcheck_init(void) 2102 { 2103 mcheck_intel_therm_init(); 2104 mce_register_decode_chain(&early_nb); 2105 mce_register_decode_chain(&mce_uc_nb); 2106 mce_register_decode_chain(&mce_default_nb); 2107 mcheck_vendor_init_severity(); 2108 2109 INIT_WORK(&mce_work, mce_gen_pool_process); 2110 init_irq_work(&mce_irq_work, mce_irq_work_cb); 2111 2112 return 0; 2113 } 2114 2115 /* 2116 * mce_syscore: PM support 2117 */ 2118 2119 /* 2120 * Disable machine checks on suspend and shutdown. We can't really handle 2121 * them later. 2122 */ 2123 static void mce_disable_error_reporting(void) 2124 { 2125 struct mce_bank *mce_banks = this_cpu_ptr(mce_banks_array); 2126 int i; 2127 2128 for (i = 0; i < this_cpu_read(mce_num_banks); i++) { 2129 struct mce_bank *b = &mce_banks[i]; 2130 2131 if (b->init) 2132 wrmsrl(msr_ops.ctl(i), 0); 2133 } 2134 return; 2135 } 2136 2137 static void vendor_disable_error_reporting(void) 2138 { 2139 /* 2140 * Don't clear on Intel or AMD or Hygon or Zhaoxin CPUs. Some of these 2141 * MSRs are socket-wide. Disabling them for just a single offlined CPU 2142 * is bad, since it will inhibit reporting for all shared resources on 2143 * the socket like the last level cache (LLC), the integrated memory 2144 * controller (iMC), etc. 2145 */ 2146 if (boot_cpu_data.x86_vendor == X86_VENDOR_INTEL || 2147 boot_cpu_data.x86_vendor == X86_VENDOR_HYGON || 2148 boot_cpu_data.x86_vendor == X86_VENDOR_AMD || 2149 boot_cpu_data.x86_vendor == X86_VENDOR_ZHAOXIN) 2150 return; 2151 2152 mce_disable_error_reporting(); 2153 } 2154 2155 static int mce_syscore_suspend(void) 2156 { 2157 vendor_disable_error_reporting(); 2158 return 0; 2159 } 2160 2161 static void mce_syscore_shutdown(void) 2162 { 2163 vendor_disable_error_reporting(); 2164 } 2165 2166 /* 2167 * On resume clear all MCE state. Don't want to see leftovers from the BIOS. 2168 * Only one CPU is active at this time, the others get re-added later using 2169 * CPU hotplug: 2170 */ 2171 static void mce_syscore_resume(void) 2172 { 2173 __mcheck_cpu_init_generic(); 2174 __mcheck_cpu_init_vendor(raw_cpu_ptr(&cpu_info)); 2175 __mcheck_cpu_init_clear_banks(); 2176 } 2177 2178 static struct syscore_ops mce_syscore_ops = { 2179 .suspend = mce_syscore_suspend, 2180 .shutdown = mce_syscore_shutdown, 2181 .resume = mce_syscore_resume, 2182 }; 2183 2184 /* 2185 * mce_device: Sysfs support 2186 */ 2187 2188 static void mce_cpu_restart(void *data) 2189 { 2190 if (!mce_available(raw_cpu_ptr(&cpu_info))) 2191 return; 2192 __mcheck_cpu_init_generic(); 2193 __mcheck_cpu_init_clear_banks(); 2194 __mcheck_cpu_init_timer(); 2195 } 2196 2197 /* Reinit MCEs after user configuration changes */ 2198 static void mce_restart(void) 2199 { 2200 mce_timer_delete_all(); 2201 on_each_cpu(mce_cpu_restart, NULL, 1); 2202 } 2203 2204 /* Toggle features for corrected errors */ 2205 static void mce_disable_cmci(void *data) 2206 { 2207 if (!mce_available(raw_cpu_ptr(&cpu_info))) 2208 return; 2209 cmci_clear(); 2210 } 2211 2212 static void mce_enable_ce(void *all) 2213 { 2214 if (!mce_available(raw_cpu_ptr(&cpu_info))) 2215 return; 2216 cmci_reenable(); 2217 cmci_recheck(); 2218 if (all) 2219 __mcheck_cpu_init_timer(); 2220 } 2221 2222 static struct bus_type mce_subsys = { 2223 .name = "machinecheck", 2224 .dev_name = "machinecheck", 2225 }; 2226 2227 DEFINE_PER_CPU(struct device *, mce_device); 2228 2229 static inline struct mce_bank_dev *attr_to_bank(struct device_attribute *attr) 2230 { 2231 return container_of(attr, struct mce_bank_dev, attr); 2232 } 2233 2234 static ssize_t show_bank(struct device *s, struct device_attribute *attr, 2235 char *buf) 2236 { 2237 u8 bank = attr_to_bank(attr)->bank; 2238 struct mce_bank *b; 2239 2240 if (bank >= per_cpu(mce_num_banks, s->id)) 2241 return -EINVAL; 2242 2243 b = &per_cpu(mce_banks_array, s->id)[bank]; 2244 2245 if (!b->init) 2246 return -ENODEV; 2247 2248 return sprintf(buf, "%llx\n", b->ctl); 2249 } 2250 2251 static ssize_t set_bank(struct device *s, struct device_attribute *attr, 2252 const char *buf, size_t size) 2253 { 2254 u8 bank = attr_to_bank(attr)->bank; 2255 struct mce_bank *b; 2256 u64 new; 2257 2258 if (kstrtou64(buf, 0, &new) < 0) 2259 return -EINVAL; 2260 2261 if (bank >= per_cpu(mce_num_banks, s->id)) 2262 return -EINVAL; 2263 2264 b = &per_cpu(mce_banks_array, s->id)[bank]; 2265 2266 if (!b->init) 2267 return -ENODEV; 2268 2269 b->ctl = new; 2270 mce_restart(); 2271 2272 return size; 2273 } 2274 2275 static ssize_t set_ignore_ce(struct device *s, 2276 struct device_attribute *attr, 2277 const char *buf, size_t size) 2278 { 2279 u64 new; 2280 2281 if (kstrtou64(buf, 0, &new) < 0) 2282 return -EINVAL; 2283 2284 mutex_lock(&mce_sysfs_mutex); 2285 if (mca_cfg.ignore_ce ^ !!new) { 2286 if (new) { 2287 /* disable ce features */ 2288 mce_timer_delete_all(); 2289 on_each_cpu(mce_disable_cmci, NULL, 1); 2290 mca_cfg.ignore_ce = true; 2291 } else { 2292 /* enable ce features */ 2293 mca_cfg.ignore_ce = false; 2294 on_each_cpu(mce_enable_ce, (void *)1, 1); 2295 } 2296 } 2297 mutex_unlock(&mce_sysfs_mutex); 2298 2299 return size; 2300 } 2301 2302 static ssize_t set_cmci_disabled(struct device *s, 2303 struct device_attribute *attr, 2304 const char *buf, size_t size) 2305 { 2306 u64 new; 2307 2308 if (kstrtou64(buf, 0, &new) < 0) 2309 return -EINVAL; 2310 2311 mutex_lock(&mce_sysfs_mutex); 2312 if (mca_cfg.cmci_disabled ^ !!new) { 2313 if (new) { 2314 /* disable cmci */ 2315 on_each_cpu(mce_disable_cmci, NULL, 1); 2316 mca_cfg.cmci_disabled = true; 2317 } else { 2318 /* enable cmci */ 2319 mca_cfg.cmci_disabled = false; 2320 on_each_cpu(mce_enable_ce, NULL, 1); 2321 } 2322 } 2323 mutex_unlock(&mce_sysfs_mutex); 2324 2325 return size; 2326 } 2327 2328 static ssize_t store_int_with_restart(struct device *s, 2329 struct device_attribute *attr, 2330 const char *buf, size_t size) 2331 { 2332 unsigned long old_check_interval = check_interval; 2333 ssize_t ret = device_store_ulong(s, attr, buf, size); 2334 2335 if (check_interval == old_check_interval) 2336 return ret; 2337 2338 mutex_lock(&mce_sysfs_mutex); 2339 mce_restart(); 2340 mutex_unlock(&mce_sysfs_mutex); 2341 2342 return ret; 2343 } 2344 2345 static DEVICE_INT_ATTR(tolerant, 0644, mca_cfg.tolerant); 2346 static DEVICE_INT_ATTR(monarch_timeout, 0644, mca_cfg.monarch_timeout); 2347 static DEVICE_BOOL_ATTR(dont_log_ce, 0644, mca_cfg.dont_log_ce); 2348 static DEVICE_BOOL_ATTR(print_all, 0644, mca_cfg.print_all); 2349 2350 static struct dev_ext_attribute dev_attr_check_interval = { 2351 __ATTR(check_interval, 0644, device_show_int, store_int_with_restart), 2352 &check_interval 2353 }; 2354 2355 static struct dev_ext_attribute dev_attr_ignore_ce = { 2356 __ATTR(ignore_ce, 0644, device_show_bool, set_ignore_ce), 2357 &mca_cfg.ignore_ce 2358 }; 2359 2360 static struct dev_ext_attribute dev_attr_cmci_disabled = { 2361 __ATTR(cmci_disabled, 0644, device_show_bool, set_cmci_disabled), 2362 &mca_cfg.cmci_disabled 2363 }; 2364 2365 static struct device_attribute *mce_device_attrs[] = { 2366 &dev_attr_tolerant.attr, 2367 &dev_attr_check_interval.attr, 2368 #ifdef CONFIG_X86_MCELOG_LEGACY 2369 &dev_attr_trigger, 2370 #endif 2371 &dev_attr_monarch_timeout.attr, 2372 &dev_attr_dont_log_ce.attr, 2373 &dev_attr_print_all.attr, 2374 &dev_attr_ignore_ce.attr, 2375 &dev_attr_cmci_disabled.attr, 2376 NULL 2377 }; 2378 2379 static cpumask_var_t mce_device_initialized; 2380 2381 static void mce_device_release(struct device *dev) 2382 { 2383 kfree(dev); 2384 } 2385 2386 /* Per CPU device init. All of the CPUs still share the same bank device: */ 2387 static int mce_device_create(unsigned int cpu) 2388 { 2389 struct device *dev; 2390 int err; 2391 int i, j; 2392 2393 if (!mce_available(&boot_cpu_data)) 2394 return -EIO; 2395 2396 dev = per_cpu(mce_device, cpu); 2397 if (dev) 2398 return 0; 2399 2400 dev = kzalloc(sizeof(*dev), GFP_KERNEL); 2401 if (!dev) 2402 return -ENOMEM; 2403 dev->id = cpu; 2404 dev->bus = &mce_subsys; 2405 dev->release = &mce_device_release; 2406 2407 err = device_register(dev); 2408 if (err) { 2409 put_device(dev); 2410 return err; 2411 } 2412 2413 for (i = 0; mce_device_attrs[i]; i++) { 2414 err = device_create_file(dev, mce_device_attrs[i]); 2415 if (err) 2416 goto error; 2417 } 2418 for (j = 0; j < per_cpu(mce_num_banks, cpu); j++) { 2419 err = device_create_file(dev, &mce_bank_devs[j].attr); 2420 if (err) 2421 goto error2; 2422 } 2423 cpumask_set_cpu(cpu, mce_device_initialized); 2424 per_cpu(mce_device, cpu) = dev; 2425 2426 return 0; 2427 error2: 2428 while (--j >= 0) 2429 device_remove_file(dev, &mce_bank_devs[j].attr); 2430 error: 2431 while (--i >= 0) 2432 device_remove_file(dev, mce_device_attrs[i]); 2433 2434 device_unregister(dev); 2435 2436 return err; 2437 } 2438 2439 static void mce_device_remove(unsigned int cpu) 2440 { 2441 struct device *dev = per_cpu(mce_device, cpu); 2442 int i; 2443 2444 if (!cpumask_test_cpu(cpu, mce_device_initialized)) 2445 return; 2446 2447 for (i = 0; mce_device_attrs[i]; i++) 2448 device_remove_file(dev, mce_device_attrs[i]); 2449 2450 for (i = 0; i < per_cpu(mce_num_banks, cpu); i++) 2451 device_remove_file(dev, &mce_bank_devs[i].attr); 2452 2453 device_unregister(dev); 2454 cpumask_clear_cpu(cpu, mce_device_initialized); 2455 per_cpu(mce_device, cpu) = NULL; 2456 } 2457 2458 /* Make sure there are no machine checks on offlined CPUs. */ 2459 static void mce_disable_cpu(void) 2460 { 2461 if (!mce_available(raw_cpu_ptr(&cpu_info))) 2462 return; 2463 2464 if (!cpuhp_tasks_frozen) 2465 cmci_clear(); 2466 2467 vendor_disable_error_reporting(); 2468 } 2469 2470 static void mce_reenable_cpu(void) 2471 { 2472 struct mce_bank *mce_banks = this_cpu_ptr(mce_banks_array); 2473 int i; 2474 2475 if (!mce_available(raw_cpu_ptr(&cpu_info))) 2476 return; 2477 2478 if (!cpuhp_tasks_frozen) 2479 cmci_reenable(); 2480 for (i = 0; i < this_cpu_read(mce_num_banks); i++) { 2481 struct mce_bank *b = &mce_banks[i]; 2482 2483 if (b->init) 2484 wrmsrl(msr_ops.ctl(i), b->ctl); 2485 } 2486 } 2487 2488 static int mce_cpu_dead(unsigned int cpu) 2489 { 2490 mce_intel_hcpu_update(cpu); 2491 2492 /* intentionally ignoring frozen here */ 2493 if (!cpuhp_tasks_frozen) 2494 cmci_rediscover(); 2495 return 0; 2496 } 2497 2498 static int mce_cpu_online(unsigned int cpu) 2499 { 2500 struct timer_list *t = this_cpu_ptr(&mce_timer); 2501 int ret; 2502 2503 mce_device_create(cpu); 2504 2505 ret = mce_threshold_create_device(cpu); 2506 if (ret) { 2507 mce_device_remove(cpu); 2508 return ret; 2509 } 2510 mce_reenable_cpu(); 2511 mce_start_timer(t); 2512 return 0; 2513 } 2514 2515 static int mce_cpu_pre_down(unsigned int cpu) 2516 { 2517 struct timer_list *t = this_cpu_ptr(&mce_timer); 2518 2519 mce_disable_cpu(); 2520 del_timer_sync(t); 2521 mce_threshold_remove_device(cpu); 2522 mce_device_remove(cpu); 2523 return 0; 2524 } 2525 2526 static __init void mce_init_banks(void) 2527 { 2528 int i; 2529 2530 for (i = 0; i < MAX_NR_BANKS; i++) { 2531 struct mce_bank_dev *b = &mce_bank_devs[i]; 2532 struct device_attribute *a = &b->attr; 2533 2534 b->bank = i; 2535 2536 sysfs_attr_init(&a->attr); 2537 a->attr.name = b->attrname; 2538 snprintf(b->attrname, ATTR_LEN, "bank%d", i); 2539 2540 a->attr.mode = 0644; 2541 a->show = show_bank; 2542 a->store = set_bank; 2543 } 2544 } 2545 2546 /* 2547 * When running on XEN, this initcall is ordered against the XEN mcelog 2548 * initcall: 2549 * 2550 * device_initcall(xen_late_init_mcelog); 2551 * device_initcall_sync(mcheck_init_device); 2552 */ 2553 static __init int mcheck_init_device(void) 2554 { 2555 int err; 2556 2557 /* 2558 * Check if we have a spare virtual bit. This will only become 2559 * a problem if/when we move beyond 5-level page tables. 2560 */ 2561 MAYBE_BUILD_BUG_ON(__VIRTUAL_MASK_SHIFT >= 63); 2562 2563 if (!mce_available(&boot_cpu_data)) { 2564 err = -EIO; 2565 goto err_out; 2566 } 2567 2568 if (!zalloc_cpumask_var(&mce_device_initialized, GFP_KERNEL)) { 2569 err = -ENOMEM; 2570 goto err_out; 2571 } 2572 2573 mce_init_banks(); 2574 2575 err = subsys_system_register(&mce_subsys, NULL); 2576 if (err) 2577 goto err_out_mem; 2578 2579 err = cpuhp_setup_state(CPUHP_X86_MCE_DEAD, "x86/mce:dead", NULL, 2580 mce_cpu_dead); 2581 if (err) 2582 goto err_out_mem; 2583 2584 /* 2585 * Invokes mce_cpu_online() on all CPUs which are online when 2586 * the state is installed. 2587 */ 2588 err = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "x86/mce:online", 2589 mce_cpu_online, mce_cpu_pre_down); 2590 if (err < 0) 2591 goto err_out_online; 2592 2593 register_syscore_ops(&mce_syscore_ops); 2594 2595 return 0; 2596 2597 err_out_online: 2598 cpuhp_remove_state(CPUHP_X86_MCE_DEAD); 2599 2600 err_out_mem: 2601 free_cpumask_var(mce_device_initialized); 2602 2603 err_out: 2604 pr_err("Unable to init MCE device (rc: %d)\n", err); 2605 2606 return err; 2607 } 2608 device_initcall_sync(mcheck_init_device); 2609 2610 /* 2611 * Old style boot options parsing. Only for compatibility. 2612 */ 2613 static int __init mcheck_disable(char *str) 2614 { 2615 mca_cfg.disabled = 1; 2616 return 1; 2617 } 2618 __setup("nomce", mcheck_disable); 2619 2620 #ifdef CONFIG_DEBUG_FS 2621 struct dentry *mce_get_debugfs_dir(void) 2622 { 2623 static struct dentry *dmce; 2624 2625 if (!dmce) 2626 dmce = debugfs_create_dir("mce", NULL); 2627 2628 return dmce; 2629 } 2630 2631 static void mce_reset(void) 2632 { 2633 cpu_missing = 0; 2634 atomic_set(&mce_fake_panicked, 0); 2635 atomic_set(&mce_executing, 0); 2636 atomic_set(&mce_callin, 0); 2637 atomic_set(&global_nwo, 0); 2638 } 2639 2640 static int fake_panic_get(void *data, u64 *val) 2641 { 2642 *val = fake_panic; 2643 return 0; 2644 } 2645 2646 static int fake_panic_set(void *data, u64 val) 2647 { 2648 mce_reset(); 2649 fake_panic = val; 2650 return 0; 2651 } 2652 2653 DEFINE_DEBUGFS_ATTRIBUTE(fake_panic_fops, fake_panic_get, fake_panic_set, 2654 "%llu\n"); 2655 2656 static void __init mcheck_debugfs_init(void) 2657 { 2658 struct dentry *dmce; 2659 2660 dmce = mce_get_debugfs_dir(); 2661 debugfs_create_file_unsafe("fake_panic", 0444, dmce, NULL, 2662 &fake_panic_fops); 2663 } 2664 #else 2665 static void __init mcheck_debugfs_init(void) { } 2666 #endif 2667 2668 DEFINE_STATIC_KEY_FALSE(mcsafe_key); 2669 EXPORT_SYMBOL_GPL(mcsafe_key); 2670 2671 static int __init mcheck_late_init(void) 2672 { 2673 if (mca_cfg.recovery) 2674 static_branch_inc(&mcsafe_key); 2675 2676 mcheck_debugfs_init(); 2677 2678 /* 2679 * Flush out everything that has been logged during early boot, now that 2680 * everything has been initialized (workqueues, decoders, ...). 2681 */ 2682 mce_schedule_work(); 2683 2684 return 0; 2685 } 2686 late_initcall(mcheck_late_init); 2687