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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 <[email protected]> 2004, 2005
6 *
7 * Send comments and feedback to Linas Vepstas <[email protected]>
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
21struct eeh_rmv_data {
22 struct list_head removed_vf_list;
23 int removed_dev_count;
24};
25
26static 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
47static 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
68static 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
76static bool eeh_dev_removed(struct eeh_dev *edev)
77{
78 return !edev || (edev->mode & EEH_DEV_REMOVED);
79}
80
81static 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 */
104static 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 */
122static 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 */
140static 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 */
163static 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
192static 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
216static 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
227static 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
250typedef enum pci_ers_result (*eeh_report_fn)(struct eeh_dev *,
251 struct pci_dev *,
252 struct pci_driver *);
253static 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
299static 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 */
323static 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, rc);
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 */
349static 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 */
369static 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
379static 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 */
422static 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 */
448static 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
466static 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
491static 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_stop_and_remove_bus_device(dev);
537 }
538}
539
540static void *eeh_pe_detach_dev(struct eeh_pe *pe, void *userdata)
541{
542 struct eeh_dev *edev, *tmp;
543
544 eeh_pe_for_each_dev(pe, edev, tmp) {
545 if (!(edev->mode & EEH_DEV_DISCONNECTED))
546 continue;
547
548 edev->mode &= ~(EEH_DEV_DISCONNECTED | EEH_DEV_IRQ_DISABLED);
549 eeh_pe_tree_remove(edev);
550 }
551
552 return NULL;
553}
554
555/*
556 * Explicitly clear PE's frozen state for PowerNV where
557 * we have frozen PE until BAR restore is completed. It's
558 * harmless to clear it for pSeries. To be consistent with
559 * PE reset (for 3 times), we try to clear the frozen state
560 * for 3 times as well.
561 */
562static int eeh_clear_pe_frozen_state(struct eeh_pe *root, bool include_passed)
563{
564 struct eeh_pe *pe;
565 int i;
566
567 eeh_for_each_pe(root, pe) {
568 if (include_passed || !eeh_pe_passed(pe)) {
569 for (i = 0; i < 3; i++)
570 if (!eeh_unfreeze_pe(pe))
571 break;
572 if (i >= 3)
573 return -EIO;
574 }
575 }
576 eeh_pe_state_clear(root, EEH_PE_ISOLATED, include_passed);
577 return 0;
578}
579
580int eeh_pe_reset_and_recover(struct eeh_pe *pe)
581{
582 int ret;
583
584 /* Bail if the PE is being recovered */
585 if (pe->state & EEH_PE_RECOVERING)
586 return 0;
587
588 /* Put the PE into recovery mode */
589 eeh_pe_state_mark(pe, EEH_PE_RECOVERING);
590
591 /* Save states */
592 eeh_pe_dev_traverse(pe, eeh_dev_save_state, NULL);
593
594 /* Issue reset */
595 ret = eeh_pe_reset_full(pe, true);
596 if (ret) {
597 eeh_pe_state_clear(pe, EEH_PE_RECOVERING, true);
598 return ret;
599 }
600
601 /* Unfreeze the PE */
602 ret = eeh_clear_pe_frozen_state(pe, true);
603 if (ret) {
604 eeh_pe_state_clear(pe, EEH_PE_RECOVERING, true);
605 return ret;
606 }
607
608 /* Restore device state */
609 eeh_pe_dev_traverse(pe, eeh_dev_restore_state, NULL);
610
611 /* Clear recovery mode */
612 eeh_pe_state_clear(pe, EEH_PE_RECOVERING, true);
613
614 return 0;
615}
616
617/**
618 * eeh_reset_device - Perform actual reset of a pci slot
619 * @driver_eeh_aware: Does the device's driver provide EEH support?
620 * @pe: EEH PE
621 * @bus: PCI bus corresponding to the isolcated slot
622 * @rmv_data: Optional, list to record removed devices
623 *
624 * This routine must be called to do reset on the indicated PE.
625 * During the reset, udev might be invoked because those affected
626 * PCI devices will be removed and then added.
627 */
628static int eeh_reset_device(struct eeh_pe *pe, struct pci_bus *bus,
629 struct eeh_rmv_data *rmv_data,
630 bool driver_eeh_aware)
631{
632 time64_t tstamp;
633 int cnt, rc;
634 struct eeh_dev *edev;
635 struct eeh_pe *tmp_pe;
636 bool any_passed = false;
637
638 eeh_for_each_pe(pe, tmp_pe)
639 any_passed |= eeh_pe_passed(tmp_pe);
640
641 /* pcibios will clear the counter; save the value */
642 cnt = pe->freeze_count;
643 tstamp = pe->tstamp;
644
645 /*
646 * We don't remove the corresponding PE instances because
647 * we need the information afterwords. The attached EEH
648 * devices are expected to be attached soon when calling
649 * into pci_hp_add_devices().
650 */
651 eeh_pe_state_mark(pe, EEH_PE_KEEP);
652 if (any_passed || driver_eeh_aware || (pe->type & EEH_PE_VF)) {
653 eeh_pe_dev_traverse(pe, eeh_rmv_device, rmv_data);
654 } else {
655 pci_hp_remove_devices(bus);
656 }
657
658 /*
659 * Reset the pci controller. (Asserts RST#; resets config space).
660 * Reconfigure bridges and devices. Don't try to bring the system
661 * up if the reset failed for some reason.
662 *
663 * During the reset, it's very dangerous to have uncontrolled PCI
664 * config accesses. So we prefer to block them. However, controlled
665 * PCI config accesses initiated from EEH itself are allowed.
666 */
667 rc = eeh_pe_reset_full(pe, false);
668 if (rc)
669 return rc;
670
671 /* Restore PE */
672 eeh_ops->configure_bridge(pe);
673 eeh_pe_restore_bars(pe);
674
675 /* Clear frozen state */
676 rc = eeh_clear_pe_frozen_state(pe, false);
677 if (rc) {
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 return 0;
713}
714
715/* The longest amount of time to wait for a pci device
716 * to come back on line, in seconds.
717 */
718#define MAX_WAIT_FOR_RECOVERY 300
719
720
721/* Walks the PE tree after processing an event to remove any stale PEs.
722 *
723 * NB: This needs to be recursive to ensure the leaf PEs get removed
724 * before their parents do. Although this is possible to do recursively
725 * we don't since this is easier to read and we need to garantee
726 * the leaf nodes will be handled first.
727 */
728static void eeh_pe_cleanup(struct eeh_pe *pe)
729{
730 struct eeh_pe *child_pe, *tmp;
731
732 list_for_each_entry_safe(child_pe, tmp, &pe->child_list, child)
733 eeh_pe_cleanup(child_pe);
734
735 if (pe->state & EEH_PE_KEEP)
736 return;
737
738 if (!(pe->state & EEH_PE_INVALID))
739 return;
740
741 if (list_empty(&pe->edevs) && list_empty(&pe->child_list)) {
742 list_del(&pe->child);
743 kfree(pe);
744 }
745}
746
747/**
748 * eeh_check_slot_presence - Check if a device is still present in a slot
749 * @pdev: pci_dev to check
750 *
751 * This function may return a false positive if we can't determine the slot's
752 * presence state. This might happen for PCIe slots if the PE containing
753 * the upstream bridge is also frozen, or the bridge is part of the same PE
754 * as the device.
755 *
756 * This shouldn't happen often, but you might see it if you hotplug a PCIe
757 * switch.
758 */
759static bool eeh_slot_presence_check(struct pci_dev *pdev)
760{
761 const struct hotplug_slot_ops *ops;
762 struct pci_slot *slot;
763 u8 state;
764 int rc;
765
766 if (!pdev)
767 return false;
768
769 if (pdev->error_state == pci_channel_io_perm_failure)
770 return false;
771
772 slot = pdev->slot;
773 if (!slot || !slot->hotplug)
774 return true;
775
776 ops = slot->hotplug->ops;
777 if (!ops || !ops->get_adapter_status)
778 return true;
779
780 /* set the attention indicator while we've got the slot ops */
781 if (ops->set_attention_status)
782 ops->set_attention_status(slot->hotplug, 1);
783
784 rc = ops->get_adapter_status(slot->hotplug, &state);
785 if (rc)
786 return true;
787
788 return !!state;
789}
790
791static void eeh_clear_slot_attention(struct pci_dev *pdev)
792{
793 const struct hotplug_slot_ops *ops;
794 struct pci_slot *slot;
795
796 if (!pdev)
797 return;
798
799 if (pdev->error_state == pci_channel_io_perm_failure)
800 return;
801
802 slot = pdev->slot;
803 if (!slot || !slot->hotplug)
804 return;
805
806 ops = slot->hotplug->ops;
807 if (!ops || !ops->set_attention_status)
808 return;
809
810 ops->set_attention_status(slot->hotplug, 0);
811}
812
813/**
814 * eeh_handle_normal_event - Handle EEH events on a specific PE
815 * @pe: EEH PE - which should not be used after we return, as it may
816 * have been invalidated.
817 *
818 * Attempts to recover the given PE. If recovery fails or the PE has failed
819 * too many times, remove the PE.
820 *
821 * While PHB detects address or data parity errors on particular PCI
822 * slot, the associated PE will be frozen. Besides, DMA's occurring
823 * to wild addresses (which usually happen due to bugs in device
824 * drivers or in PCI adapter firmware) can cause EEH error. #SERR,
825 * #PERR or other misc PCI-related errors also can trigger EEH errors.
826 *
827 * Recovery process consists of unplugging the device driver (which
828 * generated hotplug events to userspace), then issuing a PCI #RST to
829 * the device, then reconfiguring the PCI config space for all bridges
830 * & devices under this slot, and then finally restarting the device
831 * drivers (which cause a second set of hotplug events to go out to
832 * userspace).
833 */
834void eeh_handle_normal_event(struct eeh_pe *pe)
835{
836 struct pci_bus *bus;
837 struct eeh_dev *edev, *tmp;
838 struct eeh_pe *tmp_pe;
839 int rc = 0;
840 enum pci_ers_result result = PCI_ERS_RESULT_NONE;
841 struct eeh_rmv_data rmv_data =
842 {LIST_HEAD_INIT(rmv_data.removed_vf_list), 0};
843 int devices = 0;
844
845 pci_lock_rescan_remove();
846
847 bus = eeh_pe_bus_get_nolock(pe);
848 if (!bus) {
849 pr_err("%s: Cannot find PCI bus for PHB#%x-PE#%x\n",
850 __func__, pe->phb->global_number, pe->addr);
851 pci_unlock_rescan_remove();
852 return;
853 }
854
855 /*
856 * When devices are hot-removed we might get an EEH due to
857 * a driver attempting to touch the MMIO space of a removed
858 * device. In this case we don't have a device to recover
859 * so suppress the event if we can't find any present devices.
860 *
861 * The hotplug driver should take care of tearing down the
862 * device itself.
863 */
864 eeh_for_each_pe(pe, tmp_pe)
865 eeh_pe_for_each_dev(tmp_pe, edev, tmp)
866 if (eeh_slot_presence_check(edev->pdev))
867 devices++;
868
869 if (!devices) {
870 pr_warn("EEH: Frozen PHB#%x-PE#%x is empty!\n",
871 pe->phb->global_number, pe->addr);
872 /*
873 * The device is removed, tear down its state, on powernv
874 * hotplug driver would take care of it but not on pseries,
875 * permanently disable the card as it is hot removed.
876 *
877 * In the case of powernv, note that the removal of device
878 * is covered by pci rescan lock, so no problem even if hotplug
879 * driver attempts to remove the device.
880 */
881 goto recover_failed;
882 }
883
884 /* Log the event */
885 if (pe->type & EEH_PE_PHB) {
886 pr_err("EEH: Recovering PHB#%x, location: %s\n",
887 pe->phb->global_number, eeh_pe_loc_get_bus(bus));
888 } else {
889 struct eeh_pe *phb_pe = eeh_phb_pe_get(pe->phb);
890
891 pr_err("EEH: Recovering PHB#%x-PE#%x\n",
892 pe->phb->global_number, pe->addr);
893 pr_err("EEH: PE location: %s, PHB location: %s\n",
894 eeh_pe_loc_get_bus(bus),
895 eeh_pe_loc_get_bus(eeh_pe_bus_get_nolock(phb_pe)));
896 }
897
898#ifdef CONFIG_STACKTRACE
899 /*
900 * Print the saved stack trace now that we've verified there's
901 * something to recover.
902 */
903 if (pe->trace_entries) {
904 void **ptrs = (void **) pe->stack_trace;
905 int i;
906
907 pr_err("EEH: Frozen PHB#%x-PE#%x detected\n",
908 pe->phb->global_number, pe->addr);
909
910 /* FIXME: Use the same format as dump_stack() */
911 pr_err("EEH: Call Trace:\n");
912 for (i = 0; i < pe->trace_entries; i++)
913 pr_err("EEH: [%p] %pS\n", ptrs[i], ptrs[i]);
914
915 pe->trace_entries = 0;
916 }
917#endif /* CONFIG_STACKTRACE */
918
919 eeh_for_each_pe(pe, tmp_pe)
920 eeh_pe_for_each_dev(tmp_pe, edev, tmp)
921 edev->mode &= ~EEH_DEV_NO_HANDLER;
922
923 eeh_pe_update_time_stamp(pe);
924 pe->freeze_count++;
925 if (pe->freeze_count > eeh_max_freezes) {
926 pr_err("EEH: PHB#%x-PE#%x has failed %d times in the last hour and has been permanently disabled.\n",
927 pe->phb->global_number, pe->addr,
928 pe->freeze_count);
929
930 goto recover_failed;
931 }
932
933 /* Walk the various device drivers attached to this slot through
934 * a reset sequence, giving each an opportunity to do what it needs
935 * to accomplish the reset. Each child gets a report of the
936 * status ... if any child can't handle the reset, then the entire
937 * slot is dlpar removed and added.
938 *
939 * When the PHB is fenced, we have to issue a reset to recover from
940 * the error. Override the result if necessary to have partially
941 * hotplug for this case.
942 */
943 pr_warn("EEH: This PCI device has failed %d times in the last hour and will be permanently disabled after %d failures.\n",
944 pe->freeze_count, eeh_max_freezes);
945 pr_info("EEH: Notify device drivers to shutdown\n");
946 eeh_set_channel_state(pe, pci_channel_io_frozen);
947 eeh_set_irq_state(pe, false);
948 eeh_pe_report("error_detected(IO frozen)", pe,
949 eeh_report_error, &result);
950 if (result == PCI_ERS_RESULT_DISCONNECT)
951 goto recover_failed;
952
953 /*
954 * Error logged on a PHB are always fences which need a full
955 * PHB reset to clear so force that to happen.
956 */
957 if ((pe->type & EEH_PE_PHB) && result != PCI_ERS_RESULT_NONE)
958 result = PCI_ERS_RESULT_NEED_RESET;
959
960 /* Get the current PCI slot state. This can take a long time,
961 * sometimes over 300 seconds for certain systems.
962 */
963 rc = eeh_wait_state(pe, MAX_WAIT_FOR_RECOVERY * 1000);
964 if (rc < 0 || rc == EEH_STATE_NOT_SUPPORT) {
965 pr_warn("EEH: Permanent failure\n");
966 goto recover_failed;
967 }
968
969 /* Since rtas may enable MMIO when posting the error log,
970 * don't post the error log until after all dev drivers
971 * have been informed.
972 */
973 pr_info("EEH: Collect temporary log\n");
974 eeh_slot_error_detail(pe, EEH_LOG_TEMP);
975
976 /* If all device drivers were EEH-unaware, then shut
977 * down all of the device drivers, and hope they
978 * go down willingly, without panicing the system.
979 */
980 if (result == PCI_ERS_RESULT_NONE) {
981 pr_info("EEH: Reset with hotplug activity\n");
982 rc = eeh_reset_device(pe, bus, NULL, false);
983 if (rc) {
984 pr_warn("%s: Unable to reset, err=%d\n", __func__, rc);
985 goto recover_failed;
986 }
987 }
988
989 /* If all devices reported they can proceed, then re-enable MMIO */
990 if (result == PCI_ERS_RESULT_CAN_RECOVER) {
991 pr_info("EEH: Enable I/O for affected devices\n");
992 rc = eeh_pci_enable(pe, EEH_OPT_THAW_MMIO);
993 if (rc < 0)
994 goto recover_failed;
995
996 if (rc) {
997 result = PCI_ERS_RESULT_NEED_RESET;
998 } else {
999 pr_info("EEH: Notify device drivers to resume I/O\n");
1000 eeh_pe_report("mmio_enabled", pe,
1001 eeh_report_mmio_enabled, &result);
1002 }
1003 }
1004 if (result == PCI_ERS_RESULT_CAN_RECOVER) {
1005 pr_info("EEH: Enabled DMA for affected devices\n");
1006 rc = eeh_pci_enable(pe, EEH_OPT_THAW_DMA);
1007 if (rc < 0)
1008 goto recover_failed;
1009
1010 if (rc) {
1011 result = PCI_ERS_RESULT_NEED_RESET;
1012 } else {
1013 /*
1014 * We didn't do PE reset for the case. The PE
1015 * is still in frozen state. Clear it before
1016 * resuming the PE.
1017 */
1018 eeh_pe_state_clear(pe, EEH_PE_ISOLATED, true);
1019 result = PCI_ERS_RESULT_RECOVERED;
1020 }
1021 }
1022
1023 /* If any device called out for a reset, then reset the slot */
1024 if (result == PCI_ERS_RESULT_NEED_RESET) {
1025 pr_info("EEH: Reset without hotplug activity\n");
1026 rc = eeh_reset_device(pe, bus, &rmv_data, true);
1027 if (rc) {
1028 pr_warn("%s: Cannot reset, err=%d\n", __func__, rc);
1029 goto recover_failed;
1030 }
1031
1032 result = PCI_ERS_RESULT_NONE;
1033 eeh_set_channel_state(pe, pci_channel_io_normal);
1034 eeh_set_irq_state(pe, true);
1035 eeh_pe_report("slot_reset", pe, eeh_report_reset,
1036 &result);
1037 }
1038
1039 if ((result == PCI_ERS_RESULT_RECOVERED) ||
1040 (result == PCI_ERS_RESULT_NONE)) {
1041 /*
1042 * For those hot removed VFs, we should add back them after PF
1043 * get recovered properly.
1044 */
1045 list_for_each_entry_safe(edev, tmp, &rmv_data.removed_vf_list,
1046 rmv_entry) {
1047 eeh_add_virt_device(edev);
1048 list_del(&edev->rmv_entry);
1049 }
1050
1051 /* Tell all device drivers that they can resume operations */
1052 pr_info("EEH: Notify device driver to resume\n");
1053 eeh_set_channel_state(pe, pci_channel_io_normal);
1054 eeh_set_irq_state(pe, true);
1055 eeh_pe_report("resume", pe, eeh_report_resume, NULL);
1056 eeh_for_each_pe(pe, tmp_pe) {
1057 eeh_pe_for_each_dev(tmp_pe, edev, tmp) {
1058 edev->mode &= ~EEH_DEV_NO_HANDLER;
1059 edev->in_error = false;
1060 }
1061 }
1062
1063 pr_info("EEH: Recovery successful.\n");
1064 goto out;
1065 }
1066
1067recover_failed:
1068 /*
1069 * About 90% of all real-life EEH failures in the field
1070 * are due to poorly seated PCI cards. Only 10% or so are
1071 * due to actual, failed cards.
1072 */
1073 pr_err("EEH: Unable to recover from failure from PHB#%x-PE#%x.\n"
1074 "Please try reseating or replacing it\n",
1075 pe->phb->global_number, pe->addr);
1076
1077 eeh_slot_error_detail(pe, EEH_LOG_PERM);
1078
1079 /* Notify all devices that they're about to go down. */
1080 eeh_set_irq_state(pe, false);
1081 eeh_pe_report("error_detected(permanent failure)", pe,
1082 eeh_report_failure, NULL);
1083 eeh_set_channel_state(pe, pci_channel_io_perm_failure);
1084
1085 /* Mark the PE to be removed permanently */
1086 eeh_pe_state_mark(pe, EEH_PE_REMOVED);
1087
1088 /*
1089 * Shut down the device drivers for good. We mark
1090 * all removed devices correctly to avoid access
1091 * the their PCI config any more.
1092 */
1093 if (pe->type & EEH_PE_VF) {
1094 eeh_pe_dev_traverse(pe, eeh_rmv_device, NULL);
1095 eeh_pe_dev_mode_mark(pe, EEH_DEV_REMOVED);
1096 } else {
1097 eeh_pe_state_clear(pe, EEH_PE_PRI_BUS, true);
1098 eeh_pe_dev_mode_mark(pe, EEH_DEV_REMOVED);
1099
1100 bus = eeh_pe_bus_get_nolock(pe);
1101 if (bus)
1102 pci_hp_remove_devices(bus);
1103 else
1104 pr_err("%s: PCI bus for PHB#%x-PE#%x disappeared\n",
1105 __func__, pe->phb->global_number, pe->addr);
1106
1107 /* The passed PE should no longer be used */
1108 pci_unlock_rescan_remove();
1109 return;
1110 }
1111
1112out:
1113 /*
1114 * Clean up any PEs without devices. While marked as EEH_PE_RECOVERYING
1115 * we don't want to modify the PE tree structure so we do it here.
1116 */
1117 eeh_pe_cleanup(pe);
1118
1119 /* clear the slot attention LED for all recovered devices */
1120 eeh_for_each_pe(pe, tmp_pe)
1121 eeh_pe_for_each_dev(tmp_pe, edev, tmp)
1122 eeh_clear_slot_attention(edev->pdev);
1123
1124 eeh_pe_state_clear(pe, EEH_PE_RECOVERING, true);
1125
1126 pci_unlock_rescan_remove();
1127}
1128
1129/**
1130 * eeh_handle_special_event - Handle EEH events without a specific failing PE
1131 *
1132 * Called when an EEH event is detected but can't be narrowed down to a
1133 * specific PE. Iterates through possible failures and handles them as
1134 * necessary.
1135 */
1136void eeh_handle_special_event(void)
1137{
1138 struct eeh_pe *pe, *phb_pe, *tmp_pe;
1139 struct eeh_dev *edev, *tmp_edev;
1140 struct pci_bus *bus;
1141 struct pci_controller *hose;
1142 unsigned long flags;
1143 int rc;
1144
1145 pci_lock_rescan_remove();
1146
1147 do {
1148 rc = eeh_ops->next_error(&pe);
1149
1150 switch (rc) {
1151 case EEH_NEXT_ERR_DEAD_IOC:
1152 /* Mark all PHBs in dead state */
1153 eeh_serialize_lock(&flags);
1154
1155 /* Purge all events */
1156 eeh_remove_event(NULL, true);
1157
1158 list_for_each_entry(hose, &hose_list, list_node) {
1159 phb_pe = eeh_phb_pe_get(hose);
1160 if (!phb_pe) continue;
1161
1162 eeh_pe_mark_isolated(phb_pe);
1163 }
1164
1165 eeh_serialize_unlock(flags);
1166
1167 break;
1168 case EEH_NEXT_ERR_FROZEN_PE:
1169 case EEH_NEXT_ERR_FENCED_PHB:
1170 case EEH_NEXT_ERR_DEAD_PHB:
1171 /* Mark the PE in fenced state */
1172 eeh_serialize_lock(&flags);
1173
1174 /* Purge all events of the PHB */
1175 eeh_remove_event(pe, true);
1176
1177 if (rc != EEH_NEXT_ERR_DEAD_PHB)
1178 eeh_pe_state_mark(pe, EEH_PE_RECOVERING);
1179 eeh_pe_mark_isolated(pe);
1180
1181 eeh_serialize_unlock(flags);
1182
1183 break;
1184 case EEH_NEXT_ERR_NONE:
1185 pci_unlock_rescan_remove();
1186 return;
1187 default:
1188 pr_warn("%s: Invalid value %d from next_error()\n",
1189 __func__, rc);
1190 pci_unlock_rescan_remove();
1191 return;
1192 }
1193
1194 /*
1195 * For fenced PHB and frozen PE, it's handled as normal
1196 * event. We have to remove the affected PHBs for dead
1197 * PHB and IOC
1198 */
1199 if (rc == EEH_NEXT_ERR_FROZEN_PE ||
1200 rc == EEH_NEXT_ERR_FENCED_PHB) {
1201 eeh_pe_state_mark(pe, EEH_PE_RECOVERING);
1202 pci_unlock_rescan_remove();
1203 eeh_handle_normal_event(pe);
1204 pci_lock_rescan_remove();
1205 } else {
1206 eeh_for_each_pe(pe, tmp_pe)
1207 eeh_pe_for_each_dev(tmp_pe, edev, tmp_edev)
1208 edev->mode &= ~EEH_DEV_NO_HANDLER;
1209
1210 /* Notify all devices to be down */
1211 eeh_pe_state_clear(pe, EEH_PE_PRI_BUS, true);
1212 eeh_pe_report(
1213 "error_detected(permanent failure)", pe,
1214 eeh_report_failure, NULL);
1215 eeh_set_channel_state(pe, pci_channel_io_perm_failure);
1216
1217 list_for_each_entry(hose, &hose_list, list_node) {
1218 phb_pe = eeh_phb_pe_get(hose);
1219 if (!phb_pe ||
1220 !(phb_pe->state & EEH_PE_ISOLATED) ||
1221 (phb_pe->state & EEH_PE_RECOVERING))
1222 continue;
1223
1224 bus = eeh_pe_bus_get_nolock(phb_pe);
1225 if (!bus) {
1226 pr_err("%s: Cannot find PCI bus for "
1227 "PHB#%x-PE#%x\n",
1228 __func__,
1229 pe->phb->global_number,
1230 pe->addr);
1231 break;
1232 }
1233 pci_hp_remove_devices(bus);
1234 }
1235 }
1236
1237 /*
1238 * If we have detected dead IOC, we needn't proceed
1239 * any more since all PHBs would have been removed
1240 */
1241 if (rc == EEH_NEXT_ERR_DEAD_IOC)
1242 break;
1243 } while (rc != EEH_NEXT_ERR_NONE);
1244
1245 pci_unlock_rescan_remove();
1246}