arch/powerpc/kernel/eeh_driver.c

   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 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_irq_state(pe, false);
1069         eeh_pe_report("error_detected(permanent failure)", pe,
1070                       eeh_report_failure, NULL);
1071         eeh_set_channel_state(pe, pci_channel_io_perm_failure);
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_pe_report(
1189                                 "error_detected(permanent failure)", pe,
1190                                 eeh_report_failure, NULL);
1191                         eeh_set_channel_state(pe, pci_channel_io_perm_failure);
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 }