1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * PCI Error Recovery Driver for RPA-compliant PPC64 platform. 4 * Copyright IBM Corp. 2004 2005 5 * Copyright Linas Vepstas <linas@linas.org> 2004, 2005 6 * 7 * Send comments and feedback to Linas Vepstas <linas@austin.ibm.com> 8 */ 9 #include <linux/delay.h> 10 #include <linux/interrupt.h> 11 #include <linux/irq.h> 12 #include <linux/module.h> 13 #include <linux/pci.h> 14 #include <linux/pci_hotplug.h> 15 #include <asm/eeh.h> 16 #include <asm/eeh_event.h> 17 #include <asm/ppc-pci.h> 18 #include <asm/pci-bridge.h> 19 #include <asm/rtas.h> 20 21 struct eeh_rmv_data { 22 struct list_head removed_vf_list; 23 int removed_dev_count; 24 }; 25 26 static int eeh_result_priority(enum pci_ers_result result) 27 { 28 switch (result) { 29 case PCI_ERS_RESULT_NONE: 30 return 1; 31 case PCI_ERS_RESULT_NO_AER_DRIVER: 32 return 2; 33 case PCI_ERS_RESULT_RECOVERED: 34 return 3; 35 case PCI_ERS_RESULT_CAN_RECOVER: 36 return 4; 37 case PCI_ERS_RESULT_DISCONNECT: 38 return 5; 39 case PCI_ERS_RESULT_NEED_RESET: 40 return 6; 41 default: 42 WARN_ONCE(1, "Unknown pci_ers_result value: %d\n", (int)result); 43 return 0; 44 } 45 }; 46 47 static const char *pci_ers_result_name(enum pci_ers_result result) 48 { 49 switch (result) { 50 case PCI_ERS_RESULT_NONE: 51 return "none"; 52 case PCI_ERS_RESULT_CAN_RECOVER: 53 return "can recover"; 54 case PCI_ERS_RESULT_NEED_RESET: 55 return "need reset"; 56 case PCI_ERS_RESULT_DISCONNECT: 57 return "disconnect"; 58 case PCI_ERS_RESULT_RECOVERED: 59 return "recovered"; 60 case PCI_ERS_RESULT_NO_AER_DRIVER: 61 return "no AER driver"; 62 default: 63 WARN_ONCE(1, "Unknown result type: %d\n", (int)result); 64 return "unknown"; 65 } 66 }; 67 68 static enum pci_ers_result pci_ers_merge_result(enum pci_ers_result old, 69 enum pci_ers_result new) 70 { 71 if (eeh_result_priority(new) > eeh_result_priority(old)) 72 return new; 73 return old; 74 } 75 76 static bool eeh_dev_removed(struct eeh_dev *edev) 77 { 78 return !edev || (edev->mode & EEH_DEV_REMOVED); 79 } 80 81 static bool eeh_edev_actionable(struct eeh_dev *edev) 82 { 83 if (!edev->pdev) 84 return false; 85 if (edev->pdev->error_state == pci_channel_io_perm_failure) 86 return false; 87 if (eeh_dev_removed(edev)) 88 return false; 89 if (eeh_pe_passed(edev->pe)) 90 return false; 91 92 return true; 93 } 94 95 /** 96 * eeh_pcid_get - Get the PCI device driver 97 * @pdev: PCI device 98 * 99 * The function is used to retrieve the PCI device driver for 100 * the indicated PCI device. Besides, we will increase the reference 101 * of the PCI device driver to prevent that being unloaded on 102 * the fly. Otherwise, kernel crash would be seen. 103 */ 104 static inline struct pci_driver *eeh_pcid_get(struct pci_dev *pdev) 105 { 106 if (!pdev || !pdev->dev.driver) 107 return NULL; 108 109 if (!try_module_get(pdev->dev.driver->owner)) 110 return NULL; 111 112 return to_pci_driver(pdev->dev.driver); 113 } 114 115 /** 116 * eeh_pcid_put - Dereference on the PCI device driver 117 * @pdev: PCI device 118 * 119 * The function is called to do dereference on the PCI device 120 * driver of the indicated PCI device. 121 */ 122 static inline void eeh_pcid_put(struct pci_dev *pdev) 123 { 124 if (!pdev || !pdev->dev.driver) 125 return; 126 127 module_put(pdev->dev.driver->owner); 128 } 129 130 /** 131 * eeh_disable_irq - Disable interrupt for the recovering device 132 * @dev: PCI device 133 * 134 * This routine must be called when reporting temporary or permanent 135 * error to the particular PCI device to disable interrupt of that 136 * device. If the device has enabled MSI or MSI-X interrupt, we needn't 137 * do real work because EEH should freeze DMA transfers for those PCI 138 * devices encountering EEH errors, which includes MSI or MSI-X. 139 */ 140 static void eeh_disable_irq(struct eeh_dev *edev) 141 { 142 /* Don't disable MSI and MSI-X interrupts. They are 143 * effectively disabled by the DMA Stopped state 144 * when an EEH error occurs. 145 */ 146 if (edev->pdev->msi_enabled || edev->pdev->msix_enabled) 147 return; 148 149 if (!irq_has_action(edev->pdev->irq)) 150 return; 151 152 edev->mode |= EEH_DEV_IRQ_DISABLED; 153 disable_irq_nosync(edev->pdev->irq); 154 } 155 156 /** 157 * eeh_enable_irq - Enable interrupt for the recovering device 158 * @dev: PCI device 159 * 160 * This routine must be called to enable interrupt while failed 161 * device could be resumed. 162 */ 163 static void eeh_enable_irq(struct eeh_dev *edev) 164 { 165 if ((edev->mode) & EEH_DEV_IRQ_DISABLED) { 166 edev->mode &= ~EEH_DEV_IRQ_DISABLED; 167 /* 168 * FIXME !!!!! 169 * 170 * This is just ass backwards. This maze has 171 * unbalanced irq_enable/disable calls. So instead of 172 * finding the root cause it works around the warning 173 * in the irq_enable code by conditionally calling 174 * into it. 175 * 176 * That's just wrong.The warning in the core code is 177 * there to tell people to fix their asymmetries in 178 * their own code, not by abusing the core information 179 * to avoid it. 180 * 181 * I so wish that the assymetry would be the other way 182 * round and a few more irq_disable calls render that 183 * shit unusable forever. 184 * 185 * tglx 186 */ 187 if (irqd_irq_disabled(irq_get_irq_data(edev->pdev->irq))) 188 enable_irq(edev->pdev->irq); 189 } 190 } 191 192 static void eeh_dev_save_state(struct eeh_dev *edev, void *userdata) 193 { 194 struct pci_dev *pdev; 195 196 if (!edev) 197 return; 198 199 /* 200 * We cannot access the config space on some adapters. 201 * Otherwise, it will cause fenced PHB. We don't save 202 * the content in their config space and will restore 203 * from the initial config space saved when the EEH 204 * device is created. 205 */ 206 if (edev->pe && (edev->pe->state & EEH_PE_CFG_RESTRICTED)) 207 return; 208 209 pdev = eeh_dev_to_pci_dev(edev); 210 if (!pdev) 211 return; 212 213 pci_save_state(pdev); 214 } 215 216 static void eeh_set_channel_state(struct eeh_pe *root, pci_channel_state_t s) 217 { 218 struct eeh_pe *pe; 219 struct eeh_dev *edev, *tmp; 220 221 eeh_for_each_pe(root, pe) 222 eeh_pe_for_each_dev(pe, edev, tmp) 223 if (eeh_edev_actionable(edev)) 224 edev->pdev->error_state = s; 225 } 226 227 static void eeh_set_irq_state(struct eeh_pe *root, bool enable) 228 { 229 struct eeh_pe *pe; 230 struct eeh_dev *edev, *tmp; 231 232 eeh_for_each_pe(root, pe) { 233 eeh_pe_for_each_dev(pe, edev, tmp) { 234 if (!eeh_edev_actionable(edev)) 235 continue; 236 237 if (!eeh_pcid_get(edev->pdev)) 238 continue; 239 240 if (enable) 241 eeh_enable_irq(edev); 242 else 243 eeh_disable_irq(edev); 244 245 eeh_pcid_put(edev->pdev); 246 } 247 } 248 } 249 250 typedef enum pci_ers_result (*eeh_report_fn)(struct eeh_dev *, 251 struct pci_dev *, 252 struct pci_driver *); 253 static void eeh_pe_report_edev(struct eeh_dev *edev, eeh_report_fn fn, 254 enum pci_ers_result *result) 255 { 256 struct pci_dev *pdev; 257 struct pci_driver *driver; 258 enum pci_ers_result new_result; 259 260 pci_lock_rescan_remove(); 261 pdev = edev->pdev; 262 if (pdev) 263 get_device(&pdev->dev); 264 pci_unlock_rescan_remove(); 265 if (!pdev) { 266 eeh_edev_info(edev, "no device"); 267 return; 268 } 269 device_lock(&pdev->dev); 270 if (eeh_edev_actionable(edev)) { 271 driver = eeh_pcid_get(pdev); 272 273 if (!driver) 274 eeh_edev_info(edev, "no driver"); 275 else if (!driver->err_handler) 276 eeh_edev_info(edev, "driver not EEH aware"); 277 else if (edev->mode & EEH_DEV_NO_HANDLER) 278 eeh_edev_info(edev, "driver bound too late"); 279 else { 280 new_result = fn(edev, pdev, driver); 281 eeh_edev_info(edev, "%s driver reports: '%s'", 282 driver->name, 283 pci_ers_result_name(new_result)); 284 if (result) 285 *result = pci_ers_merge_result(*result, 286 new_result); 287 } 288 if (driver) 289 eeh_pcid_put(pdev); 290 } else { 291 eeh_edev_info(edev, "not actionable (%d,%d,%d)", !!pdev, 292 !eeh_dev_removed(edev), !eeh_pe_passed(edev->pe)); 293 } 294 device_unlock(&pdev->dev); 295 if (edev->pdev != pdev) 296 eeh_edev_warn(edev, "Device changed during processing!\n"); 297 put_device(&pdev->dev); 298 } 299 300 static void eeh_pe_report(const char *name, struct eeh_pe *root, 301 eeh_report_fn fn, enum pci_ers_result *result) 302 { 303 struct eeh_pe *pe; 304 struct eeh_dev *edev, *tmp; 305 306 pr_info("EEH: Beginning: '%s'\n", name); 307 eeh_for_each_pe(root, pe) eeh_pe_for_each_dev(pe, edev, tmp) 308 eeh_pe_report_edev(edev, fn, result); 309 if (result) 310 pr_info("EEH: Finished:'%s' with aggregate recovery state:'%s'\n", 311 name, pci_ers_result_name(*result)); 312 else 313 pr_info("EEH: Finished:'%s'", name); 314 } 315 316 /** 317 * eeh_report_error - Report pci error to each device driver 318 * @edev: eeh device 319 * @driver: device's PCI driver 320 * 321 * Report an EEH error to each device driver. 322 */ 323 static enum pci_ers_result eeh_report_error(struct eeh_dev *edev, 324 struct pci_dev *pdev, 325 struct pci_driver *driver) 326 { 327 enum pci_ers_result rc; 328 329 if (!driver->err_handler->error_detected) 330 return PCI_ERS_RESULT_NONE; 331 332 eeh_edev_info(edev, "Invoking %s->error_detected(IO frozen)", 333 driver->name); 334 rc = driver->err_handler->error_detected(pdev, pci_channel_io_frozen); 335 336 edev->in_error = true; 337 pci_uevent_ers(pdev, PCI_ERS_RESULT_NONE); 338 return rc; 339 } 340 341 /** 342 * eeh_report_mmio_enabled - Tell drivers that MMIO has been enabled 343 * @edev: eeh device 344 * @driver: device's PCI driver 345 * 346 * Tells each device driver that IO ports, MMIO and config space I/O 347 * are now enabled. 348 */ 349 static enum pci_ers_result eeh_report_mmio_enabled(struct eeh_dev *edev, 350 struct pci_dev *pdev, 351 struct pci_driver *driver) 352 { 353 if (!driver->err_handler->mmio_enabled) 354 return PCI_ERS_RESULT_NONE; 355 eeh_edev_info(edev, "Invoking %s->mmio_enabled()", driver->name); 356 return driver->err_handler->mmio_enabled(pdev); 357 } 358 359 /** 360 * eeh_report_reset - Tell device that slot has been reset 361 * @edev: eeh device 362 * @driver: device's PCI driver 363 * 364 * This routine must be called while EEH tries to reset particular 365 * PCI device so that the associated PCI device driver could take 366 * some actions, usually to save data the driver needs so that the 367 * driver can work again while the device is recovered. 368 */ 369 static enum pci_ers_result eeh_report_reset(struct eeh_dev *edev, 370 struct pci_dev *pdev, 371 struct pci_driver *driver) 372 { 373 if (!driver->err_handler->slot_reset || !edev->in_error) 374 return PCI_ERS_RESULT_NONE; 375 eeh_edev_info(edev, "Invoking %s->slot_reset()", driver->name); 376 return driver->err_handler->slot_reset(pdev); 377 } 378 379 static void eeh_dev_restore_state(struct eeh_dev *edev, void *userdata) 380 { 381 struct pci_dev *pdev; 382 383 if (!edev) 384 return; 385 386 /* 387 * The content in the config space isn't saved because 388 * the blocked config space on some adapters. We have 389 * to restore the initial saved config space when the 390 * EEH device is created. 391 */ 392 if (edev->pe && (edev->pe->state & EEH_PE_CFG_RESTRICTED)) { 393 if (list_is_last(&edev->entry, &edev->pe->edevs)) 394 eeh_pe_restore_bars(edev->pe); 395 396 return; 397 } 398 399 pdev = eeh_dev_to_pci_dev(edev); 400 if (!pdev) 401 return; 402 403 pci_restore_state(pdev); 404 } 405 406 /** 407 * eeh_report_resume - Tell device to resume normal operations 408 * @edev: eeh device 409 * @driver: device's PCI driver 410 * 411 * This routine must be called to notify the device driver that it 412 * could resume so that the device driver can do some initialization 413 * to make the recovered device work again. 414 */ 415 static enum pci_ers_result eeh_report_resume(struct eeh_dev *edev, 416 struct pci_dev *pdev, 417 struct pci_driver *driver) 418 { 419 if (!driver->err_handler->resume || !edev->in_error) 420 return PCI_ERS_RESULT_NONE; 421 422 eeh_edev_info(edev, "Invoking %s->resume()", driver->name); 423 driver->err_handler->resume(pdev); 424 425 pci_uevent_ers(edev->pdev, PCI_ERS_RESULT_RECOVERED); 426 #ifdef CONFIG_PCI_IOV 427 if (eeh_ops->notify_resume) 428 eeh_ops->notify_resume(edev); 429 #endif 430 return PCI_ERS_RESULT_NONE; 431 } 432 433 /** 434 * eeh_report_failure - Tell device driver that device is dead. 435 * @edev: eeh device 436 * @driver: device's PCI driver 437 * 438 * This informs the device driver that the device is permanently 439 * dead, and that no further recovery attempts will be made on it. 440 */ 441 static enum pci_ers_result eeh_report_failure(struct eeh_dev *edev, 442 struct pci_dev *pdev, 443 struct pci_driver *driver) 444 { 445 enum pci_ers_result rc; 446 447 if (!driver->err_handler->error_detected) 448 return PCI_ERS_RESULT_NONE; 449 450 eeh_edev_info(edev, "Invoking %s->error_detected(permanent failure)", 451 driver->name); 452 rc = driver->err_handler->error_detected(pdev, 453 pci_channel_io_perm_failure); 454 455 pci_uevent_ers(pdev, PCI_ERS_RESULT_DISCONNECT); 456 return rc; 457 } 458 459 static void *eeh_add_virt_device(struct eeh_dev *edev) 460 { 461 struct pci_driver *driver; 462 struct pci_dev *dev = eeh_dev_to_pci_dev(edev); 463 464 if (!(edev->physfn)) { 465 eeh_edev_warn(edev, "Not for VF\n"); 466 return NULL; 467 } 468 469 driver = eeh_pcid_get(dev); 470 if (driver) { 471 if (driver->err_handler) { 472 eeh_pcid_put(dev); 473 return NULL; 474 } 475 eeh_pcid_put(dev); 476 } 477 478 #ifdef CONFIG_PCI_IOV 479 pci_iov_add_virtfn(edev->physfn, edev->vf_index); 480 #endif 481 return NULL; 482 } 483 484 static void eeh_rmv_device(struct eeh_dev *edev, void *userdata) 485 { 486 struct pci_driver *driver; 487 struct pci_dev *dev = eeh_dev_to_pci_dev(edev); 488 struct eeh_rmv_data *rmv_data = (struct eeh_rmv_data *)userdata; 489 490 /* 491 * Actually, we should remove the PCI bridges as well. 492 * However, that's lots of complexity to do that, 493 * particularly some of devices under the bridge might 494 * support EEH. So we just care about PCI devices for 495 * simplicity here. 496 */ 497 if (!eeh_edev_actionable(edev) || 498 (dev->hdr_type == PCI_HEADER_TYPE_BRIDGE)) 499 return; 500 501 if (rmv_data) { 502 driver = eeh_pcid_get(dev); 503 if (driver) { 504 if (driver->err_handler && 505 driver->err_handler->error_detected && 506 driver->err_handler->slot_reset) { 507 eeh_pcid_put(dev); 508 return; 509 } 510 eeh_pcid_put(dev); 511 } 512 } 513 514 /* Remove it from PCI subsystem */ 515 pr_info("EEH: Removing %s without EEH sensitive driver\n", 516 pci_name(dev)); 517 edev->mode |= EEH_DEV_DISCONNECTED; 518 if (rmv_data) 519 rmv_data->removed_dev_count++; 520 521 if (edev->physfn) { 522 #ifdef CONFIG_PCI_IOV 523 pci_iov_remove_virtfn(edev->physfn, edev->vf_index); 524 edev->pdev = NULL; 525 #endif 526 if (rmv_data) 527 list_add(&edev->rmv_entry, &rmv_data->removed_vf_list); 528 } else { 529 pci_lock_rescan_remove(); 530 pci_stop_and_remove_bus_device(dev); 531 pci_unlock_rescan_remove(); 532 } 533 } 534 535 static void *eeh_pe_detach_dev(struct eeh_pe *pe, void *userdata) 536 { 537 struct eeh_dev *edev, *tmp; 538 539 eeh_pe_for_each_dev(pe, edev, tmp) { 540 if (!(edev->mode & EEH_DEV_DISCONNECTED)) 541 continue; 542 543 edev->mode &= ~(EEH_DEV_DISCONNECTED | EEH_DEV_IRQ_DISABLED); 544 eeh_pe_tree_remove(edev); 545 } 546 547 return NULL; 548 } 549 550 /* 551 * Explicitly clear PE's frozen state for PowerNV where 552 * we have frozen PE until BAR restore is completed. It's 553 * harmless to clear it for pSeries. To be consistent with 554 * PE reset (for 3 times), we try to clear the frozen state 555 * for 3 times as well. 556 */ 557 static int eeh_clear_pe_frozen_state(struct eeh_pe *root, bool include_passed) 558 { 559 struct eeh_pe *pe; 560 int i; 561 562 eeh_for_each_pe(root, pe) { 563 if (include_passed || !eeh_pe_passed(pe)) { 564 for (i = 0; i < 3; i++) 565 if (!eeh_unfreeze_pe(pe)) 566 break; 567 if (i >= 3) 568 return -EIO; 569 } 570 } 571 eeh_pe_state_clear(root, EEH_PE_ISOLATED, include_passed); 572 return 0; 573 } 574 575 int eeh_pe_reset_and_recover(struct eeh_pe *pe) 576 { 577 int ret; 578 579 /* Bail if the PE is being recovered */ 580 if (pe->state & EEH_PE_RECOVERING) 581 return 0; 582 583 /* Put the PE into recovery mode */ 584 eeh_pe_state_mark(pe, EEH_PE_RECOVERING); 585 586 /* Save states */ 587 eeh_pe_dev_traverse(pe, eeh_dev_save_state, NULL); 588 589 /* Issue reset */ 590 ret = eeh_pe_reset_full(pe, true); 591 if (ret) { 592 eeh_pe_state_clear(pe, EEH_PE_RECOVERING, true); 593 return ret; 594 } 595 596 /* Unfreeze the PE */ 597 ret = eeh_clear_pe_frozen_state(pe, true); 598 if (ret) { 599 eeh_pe_state_clear(pe, EEH_PE_RECOVERING, true); 600 return ret; 601 } 602 603 /* Restore device state */ 604 eeh_pe_dev_traverse(pe, eeh_dev_restore_state, NULL); 605 606 /* Clear recovery mode */ 607 eeh_pe_state_clear(pe, EEH_PE_RECOVERING, true); 608 609 return 0; 610 } 611 612 /** 613 * eeh_reset_device - Perform actual reset of a pci slot 614 * @driver_eeh_aware: Does the device's driver provide EEH support? 615 * @pe: EEH PE 616 * @bus: PCI bus corresponding to the isolcated slot 617 * @rmv_data: Optional, list to record removed devices 618 * 619 * This routine must be called to do reset on the indicated PE. 620 * During the reset, udev might be invoked because those affected 621 * PCI devices will be removed and then added. 622 */ 623 static int eeh_reset_device(struct eeh_pe *pe, struct pci_bus *bus, 624 struct eeh_rmv_data *rmv_data, 625 bool driver_eeh_aware) 626 { 627 time64_t tstamp; 628 int cnt, rc; 629 struct eeh_dev *edev; 630 struct eeh_pe *tmp_pe; 631 bool any_passed = false; 632 633 eeh_for_each_pe(pe, tmp_pe) 634 any_passed |= eeh_pe_passed(tmp_pe); 635 636 /* pcibios will clear the counter; save the value */ 637 cnt = pe->freeze_count; 638 tstamp = pe->tstamp; 639 640 /* 641 * We don't remove the corresponding PE instances because 642 * we need the information afterwords. The attached EEH 643 * devices are expected to be attached soon when calling 644 * into pci_hp_add_devices(). 645 */ 646 eeh_pe_state_mark(pe, EEH_PE_KEEP); 647 if (any_passed || driver_eeh_aware || (pe->type & EEH_PE_VF)) { 648 eeh_pe_dev_traverse(pe, eeh_rmv_device, rmv_data); 649 } else { 650 pci_lock_rescan_remove(); 651 pci_hp_remove_devices(bus); 652 pci_unlock_rescan_remove(); 653 } 654 655 /* 656 * Reset the pci controller. (Asserts RST#; resets config space). 657 * Reconfigure bridges and devices. Don't try to bring the system 658 * up if the reset failed for some reason. 659 * 660 * During the reset, it's very dangerous to have uncontrolled PCI 661 * config accesses. So we prefer to block them. However, controlled 662 * PCI config accesses initiated from EEH itself are allowed. 663 */ 664 rc = eeh_pe_reset_full(pe, false); 665 if (rc) 666 return rc; 667 668 pci_lock_rescan_remove(); 669 670 /* Restore PE */ 671 eeh_ops->configure_bridge(pe); 672 eeh_pe_restore_bars(pe); 673 674 /* Clear frozen state */ 675 rc = eeh_clear_pe_frozen_state(pe, false); 676 if (rc) { 677 pci_unlock_rescan_remove(); 678 return rc; 679 } 680 681 /* Give the system 5 seconds to finish running the user-space 682 * hotplug shutdown scripts, e.g. ifdown for ethernet. Yes, 683 * this is a hack, but if we don't do this, and try to bring 684 * the device up before the scripts have taken it down, 685 * potentially weird things happen. 686 */ 687 if (!driver_eeh_aware || rmv_data->removed_dev_count) { 688 pr_info("EEH: Sleep 5s ahead of %s hotplug\n", 689 (driver_eeh_aware ? "partial" : "complete")); 690 ssleep(5); 691 692 /* 693 * The EEH device is still connected with its parent 694 * PE. We should disconnect it so the binding can be 695 * rebuilt when adding PCI devices. 696 */ 697 edev = list_first_entry(&pe->edevs, struct eeh_dev, entry); 698 eeh_pe_traverse(pe, eeh_pe_detach_dev, NULL); 699 if (pe->type & EEH_PE_VF) { 700 eeh_add_virt_device(edev); 701 } else { 702 if (!driver_eeh_aware) 703 eeh_pe_state_clear(pe, EEH_PE_PRI_BUS, true); 704 pci_hp_add_devices(bus); 705 } 706 } 707 eeh_pe_state_clear(pe, EEH_PE_KEEP, true); 708 709 pe->tstamp = tstamp; 710 pe->freeze_count = cnt; 711 712 pci_unlock_rescan_remove(); 713 return 0; 714 } 715 716 /* The longest amount of time to wait for a pci device 717 * to come back on line, in seconds. 718 */ 719 #define MAX_WAIT_FOR_RECOVERY 300 720 721 722 /* Walks the PE tree after processing an event to remove any stale PEs. 723 * 724 * NB: This needs to be recursive to ensure the leaf PEs get removed 725 * before their parents do. Although this is possible to do recursively 726 * we don't since this is easier to read and we need to garantee 727 * the leaf nodes will be handled first. 728 */ 729 static void eeh_pe_cleanup(struct eeh_pe *pe) 730 { 731 struct eeh_pe *child_pe, *tmp; 732 733 list_for_each_entry_safe(child_pe, tmp, &pe->child_list, child) 734 eeh_pe_cleanup(child_pe); 735 736 if (pe->state & EEH_PE_KEEP) 737 return; 738 739 if (!(pe->state & EEH_PE_INVALID)) 740 return; 741 742 if (list_empty(&pe->edevs) && list_empty(&pe->child_list)) { 743 list_del(&pe->child); 744 kfree(pe); 745 } 746 } 747 748 /** 749 * eeh_check_slot_presence - Check if a device is still present in a slot 750 * @pdev: pci_dev to check 751 * 752 * This function may return a false positive if we can't determine the slot's 753 * presence state. This might happen for for PCIe slots if the PE containing 754 * the upstream bridge is also frozen, or the bridge is part of the same PE 755 * as the device. 756 * 757 * This shouldn't happen often, but you might see it if you hotplug a PCIe 758 * switch. 759 */ 760 static bool eeh_slot_presence_check(struct pci_dev *pdev) 761 { 762 const struct hotplug_slot_ops *ops; 763 struct pci_slot *slot; 764 u8 state; 765 int rc; 766 767 if (!pdev) 768 return false; 769 770 if (pdev->error_state == pci_channel_io_perm_failure) 771 return false; 772 773 slot = pdev->slot; 774 if (!slot || !slot->hotplug) 775 return true; 776 777 ops = slot->hotplug->ops; 778 if (!ops || !ops->get_adapter_status) 779 return true; 780 781 /* set the attention indicator while we've got the slot ops */ 782 if (ops->set_attention_status) 783 ops->set_attention_status(slot->hotplug, 1); 784 785 rc = ops->get_adapter_status(slot->hotplug, &state); 786 if (rc) 787 return true; 788 789 return !!state; 790 } 791 792 static void eeh_clear_slot_attention(struct pci_dev *pdev) 793 { 794 const struct hotplug_slot_ops *ops; 795 struct pci_slot *slot; 796 797 if (!pdev) 798 return; 799 800 if (pdev->error_state == pci_channel_io_perm_failure) 801 return; 802 803 slot = pdev->slot; 804 if (!slot || !slot->hotplug) 805 return; 806 807 ops = slot->hotplug->ops; 808 if (!ops || !ops->set_attention_status) 809 return; 810 811 ops->set_attention_status(slot->hotplug, 0); 812 } 813 814 /** 815 * eeh_handle_normal_event - Handle EEH events on a specific PE 816 * @pe: EEH PE - which should not be used after we return, as it may 817 * have been invalidated. 818 * 819 * Attempts to recover the given PE. If recovery fails or the PE has failed 820 * too many times, remove the PE. 821 * 822 * While PHB detects address or data parity errors on particular PCI 823 * slot, the associated PE will be frozen. Besides, DMA's occurring 824 * to wild addresses (which usually happen due to bugs in device 825 * drivers or in PCI adapter firmware) can cause EEH error. #SERR, 826 * #PERR or other misc PCI-related errors also can trigger EEH errors. 827 * 828 * Recovery process consists of unplugging the device driver (which 829 * generated hotplug events to userspace), then issuing a PCI #RST to 830 * the device, then reconfiguring the PCI config space for all bridges 831 * & devices under this slot, and then finally restarting the device 832 * drivers (which cause a second set of hotplug events to go out to 833 * userspace). 834 */ 835 void eeh_handle_normal_event(struct eeh_pe *pe) 836 { 837 struct pci_bus *bus; 838 struct eeh_dev *edev, *tmp; 839 struct eeh_pe *tmp_pe; 840 int rc = 0; 841 enum pci_ers_result result = PCI_ERS_RESULT_NONE; 842 struct eeh_rmv_data rmv_data = 843 {LIST_HEAD_INIT(rmv_data.removed_vf_list), 0}; 844 int devices = 0; 845 846 bus = eeh_pe_bus_get(pe); 847 if (!bus) { 848 pr_err("%s: Cannot find PCI bus for PHB#%x-PE#%x\n", 849 __func__, pe->phb->global_number, pe->addr); 850 return; 851 } 852 853 /* 854 * When devices are hot-removed we might get an EEH due to 855 * a driver attempting to touch the MMIO space of a removed 856 * device. In this case we don't have a device to recover 857 * so suppress the event if we can't find any present devices. 858 * 859 * The hotplug driver should take care of tearing down the 860 * device itself. 861 */ 862 eeh_for_each_pe(pe, tmp_pe) 863 eeh_pe_for_each_dev(tmp_pe, edev, tmp) 864 if (eeh_slot_presence_check(edev->pdev)) 865 devices++; 866 867 if (!devices) { 868 pr_debug("EEH: Frozen PHB#%x-PE#%x is empty!\n", 869 pe->phb->global_number, pe->addr); 870 goto out; /* nothing to recover */ 871 } 872 873 /* Log the event */ 874 if (pe->type & EEH_PE_PHB) { 875 pr_err("EEH: Recovering PHB#%x, location: %s\n", 876 pe->phb->global_number, eeh_pe_loc_get(pe)); 877 } else { 878 struct eeh_pe *phb_pe = eeh_phb_pe_get(pe->phb); 879 880 pr_err("EEH: Recovering PHB#%x-PE#%x\n", 881 pe->phb->global_number, pe->addr); 882 pr_err("EEH: PE location: %s, PHB location: %s\n", 883 eeh_pe_loc_get(pe), eeh_pe_loc_get(phb_pe)); 884 } 885 886 #ifdef CONFIG_STACKTRACE 887 /* 888 * Print the saved stack trace now that we've verified there's 889 * something to recover. 890 */ 891 if (pe->trace_entries) { 892 void **ptrs = (void **) pe->stack_trace; 893 int i; 894 895 pr_err("EEH: Frozen PHB#%x-PE#%x detected\n", 896 pe->phb->global_number, pe->addr); 897 898 /* FIXME: Use the same format as dump_stack() */ 899 pr_err("EEH: Call Trace:\n"); 900 for (i = 0; i < pe->trace_entries; i++) 901 pr_err("EEH: [%pK] %pS\n", ptrs[i], ptrs[i]); 902 903 pe->trace_entries = 0; 904 } 905 #endif /* CONFIG_STACKTRACE */ 906 907 eeh_for_each_pe(pe, tmp_pe) 908 eeh_pe_for_each_dev(tmp_pe, edev, tmp) 909 edev->mode &= ~EEH_DEV_NO_HANDLER; 910 911 eeh_pe_update_time_stamp(pe); 912 pe->freeze_count++; 913 if (pe->freeze_count > eeh_max_freezes) { 914 pr_err("EEH: PHB#%x-PE#%x has failed %d times in the last hour and has been permanently disabled.\n", 915 pe->phb->global_number, pe->addr, 916 pe->freeze_count); 917 918 goto recover_failed; 919 } 920 921 /* Walk the various device drivers attached to this slot through 922 * a reset sequence, giving each an opportunity to do what it needs 923 * to accomplish the reset. Each child gets a report of the 924 * status ... if any child can't handle the reset, then the entire 925 * slot is dlpar removed and added. 926 * 927 * When the PHB is fenced, we have to issue a reset to recover from 928 * the error. Override the result if necessary to have partially 929 * hotplug for this case. 930 */ 931 pr_warn("EEH: This PCI device has failed %d times in the last hour and will be permanently disabled after %d failures.\n", 932 pe->freeze_count, eeh_max_freezes); 933 pr_info("EEH: Notify device drivers to shutdown\n"); 934 eeh_set_channel_state(pe, pci_channel_io_frozen); 935 eeh_set_irq_state(pe, false); 936 eeh_pe_report("error_detected(IO frozen)", pe, 937 eeh_report_error, &result); 938 if (result == PCI_ERS_RESULT_DISCONNECT) 939 goto recover_failed; 940 941 /* 942 * Error logged on a PHB are always fences which need a full 943 * PHB reset to clear so force that to happen. 944 */ 945 if ((pe->type & EEH_PE_PHB) && result != PCI_ERS_RESULT_NONE) 946 result = PCI_ERS_RESULT_NEED_RESET; 947 948 /* Get the current PCI slot state. This can take a long time, 949 * sometimes over 300 seconds for certain systems. 950 */ 951 rc = eeh_wait_state(pe, MAX_WAIT_FOR_RECOVERY * 1000); 952 if (rc < 0 || rc == EEH_STATE_NOT_SUPPORT) { 953 pr_warn("EEH: Permanent failure\n"); 954 goto recover_failed; 955 } 956 957 /* Since rtas may enable MMIO when posting the error log, 958 * don't post the error log until after all dev drivers 959 * have been informed. 960 */ 961 pr_info("EEH: Collect temporary log\n"); 962 eeh_slot_error_detail(pe, EEH_LOG_TEMP); 963 964 /* If all device drivers were EEH-unaware, then shut 965 * down all of the device drivers, and hope they 966 * go down willingly, without panicing the system. 967 */ 968 if (result == PCI_ERS_RESULT_NONE) { 969 pr_info("EEH: Reset with hotplug activity\n"); 970 rc = eeh_reset_device(pe, bus, NULL, false); 971 if (rc) { 972 pr_warn("%s: Unable to reset, err=%d\n", __func__, rc); 973 goto recover_failed; 974 } 975 } 976 977 /* If all devices reported they can proceed, then re-enable MMIO */ 978 if (result == PCI_ERS_RESULT_CAN_RECOVER) { 979 pr_info("EEH: Enable I/O for affected devices\n"); 980 rc = eeh_pci_enable(pe, EEH_OPT_THAW_MMIO); 981 if (rc < 0) 982 goto recover_failed; 983 984 if (rc) { 985 result = PCI_ERS_RESULT_NEED_RESET; 986 } else { 987 pr_info("EEH: Notify device drivers to resume I/O\n"); 988 eeh_pe_report("mmio_enabled", pe, 989 eeh_report_mmio_enabled, &result); 990 } 991 } 992 if (result == PCI_ERS_RESULT_CAN_RECOVER) { 993 pr_info("EEH: Enabled DMA for affected devices\n"); 994 rc = eeh_pci_enable(pe, EEH_OPT_THAW_DMA); 995 if (rc < 0) 996 goto recover_failed; 997 998 if (rc) { 999 result = PCI_ERS_RESULT_NEED_RESET; 1000 } else { 1001 /* 1002 * We didn't do PE reset for the case. The PE 1003 * is still in frozen state. Clear it before 1004 * resuming the PE. 1005 */ 1006 eeh_pe_state_clear(pe, EEH_PE_ISOLATED, true); 1007 result = PCI_ERS_RESULT_RECOVERED; 1008 } 1009 } 1010 1011 /* If any device called out for a reset, then reset the slot */ 1012 if (result == PCI_ERS_RESULT_NEED_RESET) { 1013 pr_info("EEH: Reset without hotplug activity\n"); 1014 rc = eeh_reset_device(pe, bus, &rmv_data, true); 1015 if (rc) { 1016 pr_warn("%s: Cannot reset, err=%d\n", __func__, rc); 1017 goto recover_failed; 1018 } 1019 1020 result = PCI_ERS_RESULT_NONE; 1021 eeh_set_channel_state(pe, pci_channel_io_normal); 1022 eeh_set_irq_state(pe, true); 1023 eeh_pe_report("slot_reset", pe, eeh_report_reset, 1024 &result); 1025 } 1026 1027 if ((result == PCI_ERS_RESULT_RECOVERED) || 1028 (result == PCI_ERS_RESULT_NONE)) { 1029 /* 1030 * For those hot removed VFs, we should add back them after PF 1031 * get recovered properly. 1032 */ 1033 list_for_each_entry_safe(edev, tmp, &rmv_data.removed_vf_list, 1034 rmv_entry) { 1035 eeh_add_virt_device(edev); 1036 list_del(&edev->rmv_entry); 1037 } 1038 1039 /* Tell all device drivers that they can resume operations */ 1040 pr_info("EEH: Notify device driver to resume\n"); 1041 eeh_set_channel_state(pe, pci_channel_io_normal); 1042 eeh_set_irq_state(pe, true); 1043 eeh_pe_report("resume", pe, eeh_report_resume, NULL); 1044 eeh_for_each_pe(pe, tmp_pe) { 1045 eeh_pe_for_each_dev(tmp_pe, edev, tmp) { 1046 edev->mode &= ~EEH_DEV_NO_HANDLER; 1047 edev->in_error = false; 1048 } 1049 } 1050 1051 pr_info("EEH: Recovery successful.\n"); 1052 goto out; 1053 } 1054 1055 recover_failed: 1056 /* 1057 * About 90% of all real-life EEH failures in the field 1058 * are due to poorly seated PCI cards. Only 10% or so are 1059 * due to actual, failed cards. 1060 */ 1061 pr_err("EEH: Unable to recover from failure from PHB#%x-PE#%x.\n" 1062 "Please try reseating or replacing it\n", 1063 pe->phb->global_number, pe->addr); 1064 1065 eeh_slot_error_detail(pe, EEH_LOG_PERM); 1066 1067 /* Notify all devices that they're about to go down. */ 1068 eeh_set_channel_state(pe, pci_channel_io_perm_failure); 1069 eeh_set_irq_state(pe, false); 1070 eeh_pe_report("error_detected(permanent failure)", pe, 1071 eeh_report_failure, NULL); 1072 1073 /* Mark the PE to be removed permanently */ 1074 eeh_pe_state_mark(pe, EEH_PE_REMOVED); 1075 1076 /* 1077 * Shut down the device drivers for good. We mark 1078 * all removed devices correctly to avoid access 1079 * the their PCI config any more. 1080 */ 1081 if (pe->type & EEH_PE_VF) { 1082 eeh_pe_dev_traverse(pe, eeh_rmv_device, NULL); 1083 eeh_pe_dev_mode_mark(pe, EEH_DEV_REMOVED); 1084 } else { 1085 eeh_pe_state_clear(pe, EEH_PE_PRI_BUS, true); 1086 eeh_pe_dev_mode_mark(pe, EEH_DEV_REMOVED); 1087 1088 pci_lock_rescan_remove(); 1089 pci_hp_remove_devices(bus); 1090 pci_unlock_rescan_remove(); 1091 /* The passed PE should no longer be used */ 1092 return; 1093 } 1094 1095 out: 1096 /* 1097 * Clean up any PEs without devices. While marked as EEH_PE_RECOVERYING 1098 * we don't want to modify the PE tree structure so we do it here. 1099 */ 1100 eeh_pe_cleanup(pe); 1101 1102 /* clear the slot attention LED for all recovered devices */ 1103 eeh_for_each_pe(pe, tmp_pe) 1104 eeh_pe_for_each_dev(tmp_pe, edev, tmp) 1105 eeh_clear_slot_attention(edev->pdev); 1106 1107 eeh_pe_state_clear(pe, EEH_PE_RECOVERING, true); 1108 } 1109 1110 /** 1111 * eeh_handle_special_event - Handle EEH events without a specific failing PE 1112 * 1113 * Called when an EEH event is detected but can't be narrowed down to a 1114 * specific PE. Iterates through possible failures and handles them as 1115 * necessary. 1116 */ 1117 void eeh_handle_special_event(void) 1118 { 1119 struct eeh_pe *pe, *phb_pe, *tmp_pe; 1120 struct eeh_dev *edev, *tmp_edev; 1121 struct pci_bus *bus; 1122 struct pci_controller *hose; 1123 unsigned long flags; 1124 int rc; 1125 1126 1127 do { 1128 rc = eeh_ops->next_error(&pe); 1129 1130 switch (rc) { 1131 case EEH_NEXT_ERR_DEAD_IOC: 1132 /* Mark all PHBs in dead state */ 1133 eeh_serialize_lock(&flags); 1134 1135 /* Purge all events */ 1136 eeh_remove_event(NULL, true); 1137 1138 list_for_each_entry(hose, &hose_list, list_node) { 1139 phb_pe = eeh_phb_pe_get(hose); 1140 if (!phb_pe) continue; 1141 1142 eeh_pe_mark_isolated(phb_pe); 1143 } 1144 1145 eeh_serialize_unlock(flags); 1146 1147 break; 1148 case EEH_NEXT_ERR_FROZEN_PE: 1149 case EEH_NEXT_ERR_FENCED_PHB: 1150 case EEH_NEXT_ERR_DEAD_PHB: 1151 /* Mark the PE in fenced state */ 1152 eeh_serialize_lock(&flags); 1153 1154 /* Purge all events of the PHB */ 1155 eeh_remove_event(pe, true); 1156 1157 if (rc != EEH_NEXT_ERR_DEAD_PHB) 1158 eeh_pe_state_mark(pe, EEH_PE_RECOVERING); 1159 eeh_pe_mark_isolated(pe); 1160 1161 eeh_serialize_unlock(flags); 1162 1163 break; 1164 case EEH_NEXT_ERR_NONE: 1165 return; 1166 default: 1167 pr_warn("%s: Invalid value %d from next_error()\n", 1168 __func__, rc); 1169 return; 1170 } 1171 1172 /* 1173 * For fenced PHB and frozen PE, it's handled as normal 1174 * event. We have to remove the affected PHBs for dead 1175 * PHB and IOC 1176 */ 1177 if (rc == EEH_NEXT_ERR_FROZEN_PE || 1178 rc == EEH_NEXT_ERR_FENCED_PHB) { 1179 eeh_pe_state_mark(pe, EEH_PE_RECOVERING); 1180 eeh_handle_normal_event(pe); 1181 } else { 1182 eeh_for_each_pe(pe, tmp_pe) 1183 eeh_pe_for_each_dev(tmp_pe, edev, tmp_edev) 1184 edev->mode &= ~EEH_DEV_NO_HANDLER; 1185 1186 /* Notify all devices to be down */ 1187 eeh_pe_state_clear(pe, EEH_PE_PRI_BUS, true); 1188 eeh_set_channel_state(pe, pci_channel_io_perm_failure); 1189 eeh_pe_report( 1190 "error_detected(permanent failure)", pe, 1191 eeh_report_failure, NULL); 1192 1193 pci_lock_rescan_remove(); 1194 list_for_each_entry(hose, &hose_list, list_node) { 1195 phb_pe = eeh_phb_pe_get(hose); 1196 if (!phb_pe || 1197 !(phb_pe->state & EEH_PE_ISOLATED) || 1198 (phb_pe->state & EEH_PE_RECOVERING)) 1199 continue; 1200 1201 bus = eeh_pe_bus_get(phb_pe); 1202 if (!bus) { 1203 pr_err("%s: Cannot find PCI bus for " 1204 "PHB#%x-PE#%x\n", 1205 __func__, 1206 pe->phb->global_number, 1207 pe->addr); 1208 break; 1209 } 1210 pci_hp_remove_devices(bus); 1211 } 1212 pci_unlock_rescan_remove(); 1213 } 1214 1215 /* 1216 * If we have detected dead IOC, we needn't proceed 1217 * any more since all PHBs would have been removed 1218 */ 1219 if (rc == EEH_NEXT_ERR_DEAD_IOC) 1220 break; 1221 } while (rc != EEH_NEXT_ERR_NONE); 1222 } 1223