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
eeh_result_priority(enum pci_ers_result result)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
pci_ers_result_name(enum pci_ers_result result)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
pci_ers_merge_result(enum pci_ers_result old,enum pci_ers_result new)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
eeh_dev_removed(struct eeh_dev * edev)76 static bool eeh_dev_removed(struct eeh_dev *edev)
77 {
78 return !edev || (edev->mode & EEH_DEV_REMOVED);
79 }
80
eeh_edev_actionable(struct eeh_dev * edev)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 */
eeh_pcid_get(struct pci_dev * pdev)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 */
eeh_pcid_put(struct pci_dev * pdev)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 */
eeh_disable_irq(struct eeh_dev * edev)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 */
eeh_enable_irq(struct eeh_dev * edev)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
eeh_dev_save_state(struct eeh_dev * edev,void * userdata)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
eeh_set_channel_state(struct eeh_pe * root,pci_channel_state_t s)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
eeh_set_irq_state(struct eeh_pe * root,bool enable)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 *);
eeh_pe_report_edev(struct eeh_dev * edev,eeh_report_fn fn,enum pci_ers_result * result)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 pdev = edev->pdev;
261 if (pdev)
262 get_device(&pdev->dev);
263 if (!pdev) {
264 eeh_edev_info(edev, "no device");
265 *result = PCI_ERS_RESULT_DISCONNECT;
266 return;
267 }
268 device_lock(&pdev->dev);
269 if (eeh_edev_actionable(edev)) {
270 driver = eeh_pcid_get(pdev);
271
272 if (!driver)
273 eeh_edev_info(edev, "no driver");
274 else if (!driver->err_handler)
275 eeh_edev_info(edev, "driver not EEH aware");
276 else if (edev->mode & EEH_DEV_NO_HANDLER)
277 eeh_edev_info(edev, "driver bound too late");
278 else {
279 new_result = fn(edev, pdev, driver);
280 eeh_edev_info(edev, "%s driver reports: '%s'",
281 driver->name,
282 pci_ers_result_name(new_result));
283 if (result)
284 *result = pci_ers_merge_result(*result,
285 new_result);
286 }
287 if (driver)
288 eeh_pcid_put(pdev);
289 } else {
290 eeh_edev_info(edev, "not actionable (%d,%d,%d)", !!pdev,
291 !eeh_dev_removed(edev), !eeh_pe_passed(edev->pe));
292 }
293 device_unlock(&pdev->dev);
294 if (edev->pdev != pdev)
295 eeh_edev_warn(edev, "Device changed during processing!\n");
296 put_device(&pdev->dev);
297 }
298
eeh_pe_report(const char * name,struct eeh_pe * root,eeh_report_fn fn,enum pci_ers_result * result)299 static void eeh_pe_report(const char *name, struct eeh_pe *root,
300 eeh_report_fn fn, enum pci_ers_result *result)
301 {
302 struct eeh_pe *pe;
303 struct eeh_dev *edev, *tmp;
304
305 pr_info("EEH: Beginning: '%s'\n", name);
306 eeh_for_each_pe(root, pe)
307 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 */
eeh_report_error(struct eeh_dev * edev,struct pci_dev * pdev,struct pci_driver * driver)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 */
eeh_report_mmio_enabled(struct eeh_dev * edev,struct pci_dev * pdev,struct pci_driver * driver)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 */
eeh_report_reset(struct eeh_dev * edev,struct pci_dev * pdev,struct pci_driver * driver)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
eeh_dev_restore_state(struct eeh_dev * edev,void * userdata)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 pci_lock_rescan_remove();
387
388 /*
389 * The content in the config space isn't saved because
390 * the blocked config space on some adapters. We have
391 * to restore the initial saved config space when the
392 * EEH device is created.
393 */
394 if (edev->pe && (edev->pe->state & EEH_PE_CFG_RESTRICTED)) {
395 if (list_is_last(&edev->entry, &edev->pe->edevs))
396 eeh_pe_restore_bars(edev->pe);
397
398 pci_unlock_rescan_remove();
399 return;
400 }
401
402 pdev = eeh_dev_to_pci_dev(edev);
403 if (!pdev) {
404 pci_unlock_rescan_remove();
405 return;
406 }
407
408 pci_restore_state(pdev);
409
410 pci_unlock_rescan_remove();
411 }
412
413 /**
414 * eeh_report_resume - Tell device to resume normal operations
415 * @edev: eeh device
416 * @driver: device's PCI driver
417 *
418 * This routine must be called to notify the device driver that it
419 * could resume so that the device driver can do some initialization
420 * to make the recovered device work again.
421 */
eeh_report_resume(struct eeh_dev * edev,struct pci_dev * pdev,struct pci_driver * driver)422 static enum pci_ers_result eeh_report_resume(struct eeh_dev *edev,
423 struct pci_dev *pdev,
424 struct pci_driver *driver)
425 {
426 if (!driver->err_handler->resume || !edev->in_error)
427 return PCI_ERS_RESULT_NONE;
428
429 eeh_edev_info(edev, "Invoking %s->resume()", driver->name);
430 driver->err_handler->resume(pdev);
431
432 pci_uevent_ers(edev->pdev, PCI_ERS_RESULT_RECOVERED);
433 #ifdef CONFIG_PCI_IOV
434 if (eeh_ops->notify_resume)
435 eeh_ops->notify_resume(edev);
436 #endif
437 return PCI_ERS_RESULT_NONE;
438 }
439
440 /**
441 * eeh_report_failure - Tell device driver that device is dead.
442 * @edev: eeh device
443 * @driver: device's PCI driver
444 *
445 * This informs the device driver that the device is permanently
446 * dead, and that no further recovery attempts will be made on it.
447 */
eeh_report_failure(struct eeh_dev * edev,struct pci_dev * pdev,struct pci_driver * driver)448 static enum pci_ers_result eeh_report_failure(struct eeh_dev *edev,
449 struct pci_dev *pdev,
450 struct pci_driver *driver)
451 {
452 enum pci_ers_result rc;
453
454 if (!driver->err_handler->error_detected)
455 return PCI_ERS_RESULT_NONE;
456
457 eeh_edev_info(edev, "Invoking %s->error_detected(permanent failure)",
458 driver->name);
459 rc = driver->err_handler->error_detected(pdev,
460 pci_channel_io_perm_failure);
461
462 pci_uevent_ers(pdev, PCI_ERS_RESULT_DISCONNECT);
463 return rc;
464 }
465
eeh_add_virt_device(struct eeh_dev * edev)466 static void *eeh_add_virt_device(struct eeh_dev *edev)
467 {
468 struct pci_driver *driver;
469 struct pci_dev *dev = eeh_dev_to_pci_dev(edev);
470
471 if (!(edev->physfn)) {
472 eeh_edev_warn(edev, "Not for VF\n");
473 return NULL;
474 }
475
476 driver = eeh_pcid_get(dev);
477 if (driver) {
478 if (driver->err_handler) {
479 eeh_pcid_put(dev);
480 return NULL;
481 }
482 eeh_pcid_put(dev);
483 }
484
485 #ifdef CONFIG_PCI_IOV
486 pci_iov_add_virtfn(edev->physfn, edev->vf_index);
487 #endif
488 return NULL;
489 }
490
eeh_rmv_device(struct eeh_dev * edev,void * userdata)491 static void eeh_rmv_device(struct eeh_dev *edev, void *userdata)
492 {
493 struct pci_driver *driver;
494 struct pci_dev *dev = eeh_dev_to_pci_dev(edev);
495 struct eeh_rmv_data *rmv_data = (struct eeh_rmv_data *)userdata;
496
497 /*
498 * Actually, we should remove the PCI bridges as well.
499 * However, that's lots of complexity to do that,
500 * particularly some of devices under the bridge might
501 * support EEH. So we just care about PCI devices for
502 * simplicity here.
503 */
504 if (!eeh_edev_actionable(edev) ||
505 (dev->hdr_type == PCI_HEADER_TYPE_BRIDGE))
506 return;
507
508 if (rmv_data) {
509 driver = eeh_pcid_get(dev);
510 if (driver) {
511 if (driver->err_handler &&
512 driver->err_handler->error_detected &&
513 driver->err_handler->slot_reset) {
514 eeh_pcid_put(dev);
515 return;
516 }
517 eeh_pcid_put(dev);
518 }
519 }
520
521 /* Remove it from PCI subsystem */
522 pr_info("EEH: Removing %s without EEH sensitive driver\n",
523 pci_name(dev));
524 edev->mode |= EEH_DEV_DISCONNECTED;
525 if (rmv_data)
526 rmv_data->removed_dev_count++;
527
528 if (edev->physfn) {
529 #ifdef CONFIG_PCI_IOV
530 pci_iov_remove_virtfn(edev->physfn, edev->vf_index);
531 edev->pdev = NULL;
532 #endif
533 if (rmv_data)
534 list_add(&edev->rmv_entry, &rmv_data->removed_vf_list);
535 } else {
536 pci_lock_rescan_remove();
537 pci_stop_and_remove_bus_device(dev);
538 pci_unlock_rescan_remove();
539 }
540 }
541
eeh_pe_detach_dev(struct eeh_pe * pe,void * userdata)542 static void *eeh_pe_detach_dev(struct eeh_pe *pe, void *userdata)
543 {
544 struct eeh_dev *edev, *tmp;
545
546 eeh_pe_for_each_dev(pe, edev, tmp) {
547 if (!(edev->mode & EEH_DEV_DISCONNECTED))
548 continue;
549
550 edev->mode &= ~(EEH_DEV_DISCONNECTED | EEH_DEV_IRQ_DISABLED);
551 eeh_pe_tree_remove(edev);
552 }
553
554 return NULL;
555 }
556
557 /*
558 * Explicitly clear PE's frozen state for PowerNV where
559 * we have frozen PE until BAR restore is completed. It's
560 * harmless to clear it for pSeries. To be consistent with
561 * PE reset (for 3 times), we try to clear the frozen state
562 * for 3 times as well.
563 */
eeh_clear_pe_frozen_state(struct eeh_pe * root,bool include_passed)564 static int eeh_clear_pe_frozen_state(struct eeh_pe *root, bool include_passed)
565 {
566 struct eeh_pe *pe;
567 int i;
568
569 eeh_for_each_pe(root, pe) {
570 if (include_passed || !eeh_pe_passed(pe)) {
571 for (i = 0; i < 3; i++)
572 if (!eeh_unfreeze_pe(pe))
573 break;
574 if (i >= 3)
575 return -EIO;
576 }
577 }
578 eeh_pe_state_clear(root, EEH_PE_ISOLATED, include_passed);
579 return 0;
580 }
581
eeh_pe_reset_and_recover(struct eeh_pe * pe)582 int eeh_pe_reset_and_recover(struct eeh_pe *pe)
583 {
584 int ret;
585
586 /* Bail if the PE is being recovered */
587 if (pe->state & EEH_PE_RECOVERING)
588 return 0;
589
590 /* Put the PE into recovery mode */
591 eeh_pe_state_mark(pe, EEH_PE_RECOVERING);
592
593 /* Save states */
594 eeh_pe_dev_traverse(pe, eeh_dev_save_state, NULL);
595
596 /* Issue reset */
597 ret = eeh_pe_reset_full(pe, true);
598 if (ret) {
599 eeh_pe_state_clear(pe, EEH_PE_RECOVERING, true);
600 return ret;
601 }
602
603 /* Unfreeze the PE */
604 ret = eeh_clear_pe_frozen_state(pe, true);
605 if (ret) {
606 eeh_pe_state_clear(pe, EEH_PE_RECOVERING, true);
607 return ret;
608 }
609
610 /* Restore device state */
611 eeh_pe_dev_traverse(pe, eeh_dev_restore_state, NULL);
612
613 /* Clear recovery mode */
614 eeh_pe_state_clear(pe, EEH_PE_RECOVERING, true);
615
616 return 0;
617 }
618
619 /**
620 * eeh_reset_device - Perform actual reset of a pci slot
621 * @driver_eeh_aware: Does the device's driver provide EEH support?
622 * @pe: EEH PE
623 * @bus: PCI bus corresponding to the isolcated slot
624 * @rmv_data: Optional, list to record removed devices
625 *
626 * This routine must be called to do reset on the indicated PE.
627 * During the reset, udev might be invoked because those affected
628 * PCI devices will be removed and then added.
629 */
eeh_reset_device(struct eeh_pe * pe,struct pci_bus * bus,struct eeh_rmv_data * rmv_data,bool driver_eeh_aware)630 static int eeh_reset_device(struct eeh_pe *pe, struct pci_bus *bus,
631 struct eeh_rmv_data *rmv_data,
632 bool driver_eeh_aware)
633 {
634 time64_t tstamp;
635 int cnt, rc;
636 struct eeh_dev *edev;
637 struct eeh_pe *tmp_pe;
638 bool any_passed = false;
639
640 eeh_for_each_pe(pe, tmp_pe)
641 any_passed |= eeh_pe_passed(tmp_pe);
642
643 /* pcibios will clear the counter; save the value */
644 cnt = pe->freeze_count;
645 tstamp = pe->tstamp;
646
647 /*
648 * We don't remove the corresponding PE instances because
649 * we need the information afterwords. The attached EEH
650 * devices are expected to be attached soon when calling
651 * into pci_hp_add_devices().
652 */
653 eeh_pe_state_mark(pe, EEH_PE_KEEP);
654 if (any_passed || driver_eeh_aware || (pe->type & EEH_PE_VF)) {
655 eeh_pe_dev_traverse(pe, eeh_rmv_device, rmv_data);
656 } else {
657 pci_hp_remove_devices(bus);
658 }
659
660 /*
661 * Reset the pci controller. (Asserts RST#; resets config space).
662 * Reconfigure bridges and devices. Don't try to bring the system
663 * up if the reset failed for some reason.
664 *
665 * During the reset, it's very dangerous to have uncontrolled PCI
666 * config accesses. So we prefer to block them. However, controlled
667 * PCI config accesses initiated from EEH itself are allowed.
668 */
669 rc = eeh_pe_reset_full(pe, false);
670 if (rc)
671 return rc;
672
673 /* Restore PE */
674 eeh_ops->configure_bridge(pe);
675 eeh_pe_restore_bars(pe);
676
677 /* Clear frozen state */
678 rc = eeh_clear_pe_frozen_state(pe, false);
679 if (rc) {
680 return rc;
681 }
682
683 /* Give the system 5 seconds to finish running the user-space
684 * hotplug shutdown scripts, e.g. ifdown for ethernet. Yes,
685 * this is a hack, but if we don't do this, and try to bring
686 * the device up before the scripts have taken it down,
687 * potentially weird things happen.
688 */
689 if (!driver_eeh_aware || rmv_data->removed_dev_count) {
690 pr_info("EEH: Sleep 5s ahead of %s hotplug\n",
691 (driver_eeh_aware ? "partial" : "complete"));
692 ssleep(5);
693
694 /*
695 * The EEH device is still connected with its parent
696 * PE. We should disconnect it so the binding can be
697 * rebuilt when adding PCI devices.
698 */
699 edev = list_first_entry(&pe->edevs, struct eeh_dev, entry);
700 eeh_pe_traverse(pe, eeh_pe_detach_dev, NULL);
701 if (pe->type & EEH_PE_VF) {
702 eeh_add_virt_device(edev);
703 } else {
704 if (!driver_eeh_aware)
705 eeh_pe_state_clear(pe, EEH_PE_PRI_BUS, true);
706 pci_hp_add_devices(bus);
707 }
708 }
709 eeh_pe_state_clear(pe, EEH_PE_KEEP, true);
710
711 pe->tstamp = tstamp;
712 pe->freeze_count = cnt;
713
714 return 0;
715 }
716
717 /* The longest amount of time to wait for a pci device
718 * to come back on line, in seconds.
719 */
720 #define MAX_WAIT_FOR_RECOVERY 300
721
722
723 /* Walks the PE tree after processing an event to remove any stale PEs.
724 *
725 * NB: This needs to be recursive to ensure the leaf PEs get removed
726 * before their parents do. Although this is possible to do recursively
727 * we don't since this is easier to read and we need to garantee
728 * the leaf nodes will be handled first.
729 */
eeh_pe_cleanup(struct eeh_pe * pe)730 static void eeh_pe_cleanup(struct eeh_pe *pe)
731 {
732 struct eeh_pe *child_pe, *tmp;
733
734 list_for_each_entry_safe(child_pe, tmp, &pe->child_list, child)
735 eeh_pe_cleanup(child_pe);
736
737 if (pe->state & EEH_PE_KEEP)
738 return;
739
740 if (!(pe->state & EEH_PE_INVALID))
741 return;
742
743 if (list_empty(&pe->edevs) && list_empty(&pe->child_list)) {
744 list_del(&pe->child);
745 kfree(pe);
746 }
747 }
748
749 /**
750 * eeh_check_slot_presence - Check if a device is still present in a slot
751 * @pdev: pci_dev to check
752 *
753 * This function may return a false positive if we can't determine the slot's
754 * presence state. This might happen for PCIe slots if the PE containing
755 * the upstream bridge is also frozen, or the bridge is part of the same PE
756 * as the device.
757 *
758 * This shouldn't happen often, but you might see it if you hotplug a PCIe
759 * switch.
760 */
eeh_slot_presence_check(struct pci_dev * pdev)761 static bool eeh_slot_presence_check(struct pci_dev *pdev)
762 {
763 const struct hotplug_slot_ops *ops;
764 struct pci_slot *slot;
765 u8 state;
766 int rc;
767
768 if (!pdev)
769 return false;
770
771 if (pdev->error_state == pci_channel_io_perm_failure)
772 return false;
773
774 slot = pdev->slot;
775 if (!slot || !slot->hotplug)
776 return true;
777
778 ops = slot->hotplug->ops;
779 if (!ops || !ops->get_adapter_status)
780 return true;
781
782 /* set the attention indicator while we've got the slot ops */
783 if (ops->set_attention_status)
784 ops->set_attention_status(slot->hotplug, 1);
785
786 rc = ops->get_adapter_status(slot->hotplug, &state);
787 if (rc)
788 return true;
789
790 return !!state;
791 }
792
eeh_clear_slot_attention(struct pci_dev * pdev)793 static void eeh_clear_slot_attention(struct pci_dev *pdev)
794 {
795 const struct hotplug_slot_ops *ops;
796 struct pci_slot *slot;
797
798 if (!pdev)
799 return;
800
801 if (pdev->error_state == pci_channel_io_perm_failure)
802 return;
803
804 slot = pdev->slot;
805 if (!slot || !slot->hotplug)
806 return;
807
808 ops = slot->hotplug->ops;
809 if (!ops || !ops->set_attention_status)
810 return;
811
812 ops->set_attention_status(slot->hotplug, 0);
813 }
814
815 /**
816 * eeh_handle_normal_event - Handle EEH events on a specific PE
817 * @pe: EEH PE - which should not be used after we return, as it may
818 * have been invalidated.
819 *
820 * Attempts to recover the given PE. If recovery fails or the PE has failed
821 * too many times, remove the PE.
822 *
823 * While PHB detects address or data parity errors on particular PCI
824 * slot, the associated PE will be frozen. Besides, DMA's occurring
825 * to wild addresses (which usually happen due to bugs in device
826 * drivers or in PCI adapter firmware) can cause EEH error. #SERR,
827 * #PERR or other misc PCI-related errors also can trigger EEH errors.
828 *
829 * Recovery process consists of unplugging the device driver (which
830 * generated hotplug events to userspace), then issuing a PCI #RST to
831 * the device, then reconfiguring the PCI config space for all bridges
832 * & devices under this slot, and then finally restarting the device
833 * drivers (which cause a second set of hotplug events to go out to
834 * userspace).
835 */
eeh_handle_normal_event(struct eeh_pe * pe)836 void eeh_handle_normal_event(struct eeh_pe *pe)
837 {
838 struct pci_bus *bus;
839 struct eeh_dev *edev, *tmp;
840 struct eeh_pe *tmp_pe;
841 int rc = 0;
842 enum pci_ers_result result = PCI_ERS_RESULT_NONE;
843 struct eeh_rmv_data rmv_data =
844 {LIST_HEAD_INIT(rmv_data.removed_vf_list), 0};
845 int devices = 0;
846
847 pci_lock_rescan_remove();
848
849 bus = eeh_pe_bus_get(pe);
850 if (!bus) {
851 pr_err("%s: Cannot find PCI bus for PHB#%x-PE#%x\n",
852 __func__, pe->phb->global_number, pe->addr);
853 pci_unlock_rescan_remove();
854 return;
855 }
856
857 /*
858 * When devices are hot-removed we might get an EEH due to
859 * a driver attempting to touch the MMIO space of a removed
860 * device. In this case we don't have a device to recover
861 * so suppress the event if we can't find any present devices.
862 *
863 * The hotplug driver should take care of tearing down the
864 * device itself.
865 */
866 eeh_for_each_pe(pe, tmp_pe)
867 eeh_pe_for_each_dev(tmp_pe, edev, tmp)
868 if (eeh_slot_presence_check(edev->pdev))
869 devices++;
870
871 if (!devices) {
872 pr_warn("EEH: Frozen PHB#%x-PE#%x is empty!\n",
873 pe->phb->global_number, pe->addr);
874 /*
875 * The device is removed, tear down its state, on powernv
876 * hotplug driver would take care of it but not on pseries,
877 * permanently disable the card as it is hot removed.
878 *
879 * In the case of powernv, note that the removal of device
880 * is covered by pci rescan lock, so no problem even if hotplug
881 * driver attempts to remove the device.
882 */
883 goto recover_failed;
884 }
885
886 /* Log the event */
887 if (pe->type & EEH_PE_PHB) {
888 pr_err("EEH: Recovering PHB#%x, location: %s\n",
889 pe->phb->global_number, eeh_pe_loc_get(pe));
890 } else {
891 struct eeh_pe *phb_pe = eeh_phb_pe_get(pe->phb);
892
893 pr_err("EEH: Recovering PHB#%x-PE#%x\n",
894 pe->phb->global_number, pe->addr);
895 pr_err("EEH: PE location: %s, PHB location: %s\n",
896 eeh_pe_loc_get(pe), eeh_pe_loc_get(phb_pe));
897 }
898
899 #ifdef CONFIG_STACKTRACE
900 /*
901 * Print the saved stack trace now that we've verified there's
902 * something to recover.
903 */
904 if (pe->trace_entries) {
905 void **ptrs = (void **) pe->stack_trace;
906 int i;
907
908 pr_err("EEH: Frozen PHB#%x-PE#%x detected\n",
909 pe->phb->global_number, pe->addr);
910
911 /* FIXME: Use the same format as dump_stack() */
912 pr_err("EEH: Call Trace:\n");
913 for (i = 0; i < pe->trace_entries; i++)
914 pr_err("EEH: [%p] %pS\n", ptrs[i], ptrs[i]);
915
916 pe->trace_entries = 0;
917 }
918 #endif /* CONFIG_STACKTRACE */
919
920 eeh_for_each_pe(pe, tmp_pe)
921 eeh_pe_for_each_dev(tmp_pe, edev, tmp)
922 edev->mode &= ~EEH_DEV_NO_HANDLER;
923
924 eeh_pe_update_time_stamp(pe);
925 pe->freeze_count++;
926 if (pe->freeze_count > eeh_max_freezes) {
927 pr_err("EEH: PHB#%x-PE#%x has failed %d times in the last hour and has been permanently disabled.\n",
928 pe->phb->global_number, pe->addr,
929 pe->freeze_count);
930
931 goto recover_failed;
932 }
933
934 /* Walk the various device drivers attached to this slot through
935 * a reset sequence, giving each an opportunity to do what it needs
936 * to accomplish the reset. Each child gets a report of the
937 * status ... if any child can't handle the reset, then the entire
938 * slot is dlpar removed and added.
939 *
940 * When the PHB is fenced, we have to issue a reset to recover from
941 * the error. Override the result if necessary to have partially
942 * hotplug for this case.
943 */
944 pr_warn("EEH: This PCI device has failed %d times in the last hour and will be permanently disabled after %d failures.\n",
945 pe->freeze_count, eeh_max_freezes);
946 pr_info("EEH: Notify device drivers to shutdown\n");
947 eeh_set_channel_state(pe, pci_channel_io_frozen);
948 eeh_set_irq_state(pe, false);
949 eeh_pe_report("error_detected(IO frozen)", pe,
950 eeh_report_error, &result);
951 if (result == PCI_ERS_RESULT_DISCONNECT)
952 goto recover_failed;
953
954 /*
955 * Error logged on a PHB are always fences which need a full
956 * PHB reset to clear so force that to happen.
957 */
958 if ((pe->type & EEH_PE_PHB) && result != PCI_ERS_RESULT_NONE)
959 result = PCI_ERS_RESULT_NEED_RESET;
960
961 /* Get the current PCI slot state. This can take a long time,
962 * sometimes over 300 seconds for certain systems.
963 */
964 rc = eeh_wait_state(pe, MAX_WAIT_FOR_RECOVERY * 1000);
965 if (rc < 0 || rc == EEH_STATE_NOT_SUPPORT) {
966 pr_warn("EEH: Permanent failure\n");
967 goto recover_failed;
968 }
969
970 /* Since rtas may enable MMIO when posting the error log,
971 * don't post the error log until after all dev drivers
972 * have been informed.
973 */
974 pr_info("EEH: Collect temporary log\n");
975 eeh_slot_error_detail(pe, EEH_LOG_TEMP);
976
977 /* If all device drivers were EEH-unaware, then shut
978 * down all of the device drivers, and hope they
979 * go down willingly, without panicing the system.
980 */
981 if (result == PCI_ERS_RESULT_NONE) {
982 pr_info("EEH: Reset with hotplug activity\n");
983 rc = eeh_reset_device(pe, bus, NULL, false);
984 if (rc) {
985 pr_warn("%s: Unable to reset, err=%d\n", __func__, rc);
986 goto recover_failed;
987 }
988 }
989
990 /* If all devices reported they can proceed, then re-enable MMIO */
991 if (result == PCI_ERS_RESULT_CAN_RECOVER) {
992 pr_info("EEH: Enable I/O for affected devices\n");
993 rc = eeh_pci_enable(pe, EEH_OPT_THAW_MMIO);
994 if (rc < 0)
995 goto recover_failed;
996
997 if (rc) {
998 result = PCI_ERS_RESULT_NEED_RESET;
999 } else {
1000 pr_info("EEH: Notify device drivers to resume I/O\n");
1001 eeh_pe_report("mmio_enabled", pe,
1002 eeh_report_mmio_enabled, &result);
1003 }
1004 }
1005 if (result == PCI_ERS_RESULT_CAN_RECOVER) {
1006 pr_info("EEH: Enabled DMA for affected devices\n");
1007 rc = eeh_pci_enable(pe, EEH_OPT_THAW_DMA);
1008 if (rc < 0)
1009 goto recover_failed;
1010
1011 if (rc) {
1012 result = PCI_ERS_RESULT_NEED_RESET;
1013 } else {
1014 /*
1015 * We didn't do PE reset for the case. The PE
1016 * is still in frozen state. Clear it before
1017 * resuming the PE.
1018 */
1019 eeh_pe_state_clear(pe, EEH_PE_ISOLATED, true);
1020 result = PCI_ERS_RESULT_RECOVERED;
1021 }
1022 }
1023
1024 /* If any device called out for a reset, then reset the slot */
1025 if (result == PCI_ERS_RESULT_NEED_RESET) {
1026 pr_info("EEH: Reset without hotplug activity\n");
1027 rc = eeh_reset_device(pe, bus, &rmv_data, true);
1028 if (rc) {
1029 pr_warn("%s: Cannot reset, err=%d\n", __func__, rc);
1030 goto recover_failed;
1031 }
1032
1033 result = PCI_ERS_RESULT_NONE;
1034 eeh_set_channel_state(pe, pci_channel_io_normal);
1035 eeh_set_irq_state(pe, true);
1036 eeh_pe_report("slot_reset", pe, eeh_report_reset,
1037 &result);
1038 }
1039
1040 if ((result == PCI_ERS_RESULT_RECOVERED) ||
1041 (result == PCI_ERS_RESULT_NONE)) {
1042 /*
1043 * For those hot removed VFs, we should add back them after PF
1044 * get recovered properly.
1045 */
1046 list_for_each_entry_safe(edev, tmp, &rmv_data.removed_vf_list,
1047 rmv_entry) {
1048 eeh_add_virt_device(edev);
1049 list_del(&edev->rmv_entry);
1050 }
1051
1052 /* Tell all device drivers that they can resume operations */
1053 pr_info("EEH: Notify device driver to resume\n");
1054 eeh_set_channel_state(pe, pci_channel_io_normal);
1055 eeh_set_irq_state(pe, true);
1056 eeh_pe_report("resume", pe, eeh_report_resume, NULL);
1057 eeh_for_each_pe(pe, tmp_pe) {
1058 eeh_pe_for_each_dev(tmp_pe, edev, tmp) {
1059 edev->mode &= ~EEH_DEV_NO_HANDLER;
1060 edev->in_error = false;
1061 }
1062 }
1063
1064 pr_info("EEH: Recovery successful.\n");
1065 goto out;
1066 }
1067
1068 recover_failed:
1069 /*
1070 * About 90% of all real-life EEH failures in the field
1071 * are due to poorly seated PCI cards. Only 10% or so are
1072 * due to actual, failed cards.
1073 */
1074 pr_err("EEH: Unable to recover from failure from PHB#%x-PE#%x.\n"
1075 "Please try reseating or replacing it\n",
1076 pe->phb->global_number, pe->addr);
1077
1078 eeh_slot_error_detail(pe, EEH_LOG_PERM);
1079
1080 /* Notify all devices that they're about to go down. */
1081 eeh_set_irq_state(pe, false);
1082 eeh_pe_report("error_detected(permanent failure)", pe,
1083 eeh_report_failure, NULL);
1084 eeh_set_channel_state(pe, pci_channel_io_perm_failure);
1085
1086 /* Mark the PE to be removed permanently */
1087 eeh_pe_state_mark(pe, EEH_PE_REMOVED);
1088
1089 /*
1090 * Shut down the device drivers for good. We mark
1091 * all removed devices correctly to avoid access
1092 * the their PCI config any more.
1093 */
1094 if (pe->type & EEH_PE_VF) {
1095 eeh_pe_dev_traverse(pe, eeh_rmv_device, NULL);
1096 eeh_pe_dev_mode_mark(pe, EEH_DEV_REMOVED);
1097 } else {
1098 eeh_pe_state_clear(pe, EEH_PE_PRI_BUS, true);
1099 eeh_pe_dev_mode_mark(pe, EEH_DEV_REMOVED);
1100
1101 bus = eeh_pe_bus_get(pe);
1102 if (bus)
1103 pci_hp_remove_devices(bus);
1104 else
1105 pr_err("%s: PCI bus for PHB#%x-PE#%x disappeared\n",
1106 __func__, pe->phb->global_number, pe->addr);
1107
1108 /* The passed PE should no longer be used */
1109 pci_unlock_rescan_remove();
1110 return;
1111 }
1112
1113 out:
1114 /*
1115 * Clean up any PEs without devices. While marked as EEH_PE_RECOVERYING
1116 * we don't want to modify the PE tree structure so we do it here.
1117 */
1118 eeh_pe_cleanup(pe);
1119
1120 /* clear the slot attention LED for all recovered devices */
1121 eeh_for_each_pe(pe, tmp_pe)
1122 eeh_pe_for_each_dev(tmp_pe, edev, tmp)
1123 eeh_clear_slot_attention(edev->pdev);
1124
1125 eeh_pe_state_clear(pe, EEH_PE_RECOVERING, true);
1126
1127 pci_unlock_rescan_remove();
1128 }
1129
1130 /**
1131 * eeh_handle_special_event - Handle EEH events without a specific failing PE
1132 *
1133 * Called when an EEH event is detected but can't be narrowed down to a
1134 * specific PE. Iterates through possible failures and handles them as
1135 * necessary.
1136 */
eeh_handle_special_event(void)1137 void eeh_handle_special_event(void)
1138 {
1139 struct eeh_pe *pe, *phb_pe, *tmp_pe;
1140 struct eeh_dev *edev, *tmp_edev;
1141 struct pci_bus *bus;
1142 struct pci_controller *hose;
1143 unsigned long flags;
1144 int rc;
1145
1146 pci_lock_rescan_remove();
1147
1148 do {
1149 rc = eeh_ops->next_error(&pe);
1150
1151 switch (rc) {
1152 case EEH_NEXT_ERR_DEAD_IOC:
1153 /* Mark all PHBs in dead state */
1154 eeh_serialize_lock(&flags);
1155
1156 /* Purge all events */
1157 eeh_remove_event(NULL, true);
1158
1159 list_for_each_entry(hose, &hose_list, list_node) {
1160 phb_pe = eeh_phb_pe_get(hose);
1161 if (!phb_pe) continue;
1162
1163 eeh_pe_mark_isolated(phb_pe);
1164 }
1165
1166 eeh_serialize_unlock(flags);
1167
1168 break;
1169 case EEH_NEXT_ERR_FROZEN_PE:
1170 case EEH_NEXT_ERR_FENCED_PHB:
1171 case EEH_NEXT_ERR_DEAD_PHB:
1172 /* Mark the PE in fenced state */
1173 eeh_serialize_lock(&flags);
1174
1175 /* Purge all events of the PHB */
1176 eeh_remove_event(pe, true);
1177
1178 if (rc != EEH_NEXT_ERR_DEAD_PHB)
1179 eeh_pe_state_mark(pe, EEH_PE_RECOVERING);
1180 eeh_pe_mark_isolated(pe);
1181
1182 eeh_serialize_unlock(flags);
1183
1184 break;
1185 case EEH_NEXT_ERR_NONE:
1186 pci_unlock_rescan_remove();
1187 return;
1188 default:
1189 pr_warn("%s: Invalid value %d from next_error()\n",
1190 __func__, rc);
1191 pci_unlock_rescan_remove();
1192 return;
1193 }
1194
1195 /*
1196 * For fenced PHB and frozen PE, it's handled as normal
1197 * event. We have to remove the affected PHBs for dead
1198 * PHB and IOC
1199 */
1200 if (rc == EEH_NEXT_ERR_FROZEN_PE ||
1201 rc == EEH_NEXT_ERR_FENCED_PHB) {
1202 eeh_pe_state_mark(pe, EEH_PE_RECOVERING);
1203 pci_unlock_rescan_remove();
1204 eeh_handle_normal_event(pe);
1205 pci_lock_rescan_remove();
1206 } else {
1207 eeh_for_each_pe(pe, tmp_pe)
1208 eeh_pe_for_each_dev(tmp_pe, edev, tmp_edev)
1209 edev->mode &= ~EEH_DEV_NO_HANDLER;
1210
1211 /* Notify all devices to be down */
1212 eeh_pe_state_clear(pe, EEH_PE_PRI_BUS, true);
1213 eeh_pe_report(
1214 "error_detected(permanent failure)", pe,
1215 eeh_report_failure, NULL);
1216 eeh_set_channel_state(pe, pci_channel_io_perm_failure);
1217
1218 list_for_each_entry(hose, &hose_list, list_node) {
1219 phb_pe = eeh_phb_pe_get(hose);
1220 if (!phb_pe ||
1221 !(phb_pe->state & EEH_PE_ISOLATED) ||
1222 (phb_pe->state & EEH_PE_RECOVERING))
1223 continue;
1224
1225 bus = eeh_pe_bus_get(phb_pe);
1226 if (!bus) {
1227 pr_err("%s: Cannot find PCI bus for "
1228 "PHB#%x-PE#%x\n",
1229 __func__,
1230 pe->phb->global_number,
1231 pe->addr);
1232 break;
1233 }
1234 pci_hp_remove_devices(bus);
1235 }
1236 }
1237
1238 /*
1239 * If we have detected dead IOC, we needn't proceed
1240 * any more since all PHBs would have been removed
1241 */
1242 if (rc == EEH_NEXT_ERR_DEAD_IOC)
1243 break;
1244 } while (rc != EEH_NEXT_ERR_NONE);
1245
1246 pci_unlock_rescan_remove();
1247 }
1248