GNU Linux-libre 6.7.9-gnu
[releases.git] / 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", 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", 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 }