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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-27 10:05:51 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-27 10:05:51 +0000
commit5d1646d90e1f2cceb9f0828f4b28318cd0ec7744 (patch)
treea94efe259b9009378be6d90eb30d2b019d95c194 /arch/powerpc/kernel/eeh_driver.c
parentInitial commit. (diff)
downloadlinux-5d1646d90e1f2cceb9f0828f4b28318cd0ec7744.tar.xz
linux-5d1646d90e1f2cceb9f0828f4b28318cd0ec7744.zip
Adding upstream version 5.10.209.upstream/5.10.209
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'arch/powerpc/kernel/eeh_driver.c')
-rw-r--r--arch/powerpc/kernel/eeh_driver.c1226
1 files changed, 1226 insertions, 0 deletions
diff --git a/arch/powerpc/kernel/eeh_driver.c b/arch/powerpc/kernel/eeh_driver.c
new file mode 100644
index 000000000..665d847ef
--- /dev/null
+++ b/arch/powerpc/kernel/eeh_driver.c
@@ -0,0 +1,1226 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * PCI Error Recovery Driver for RPA-compliant PPC64 platform.
+ * Copyright IBM Corp. 2004 2005
+ * Copyright Linas Vepstas <linas@linas.org> 2004, 2005
+ *
+ * Send comments and feedback to Linas Vepstas <linas@austin.ibm.com>
+ */
+#include <linux/delay.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/module.h>
+#include <linux/pci.h>
+#include <linux/pci_hotplug.h>
+#include <asm/eeh.h>
+#include <asm/eeh_event.h>
+#include <asm/ppc-pci.h>
+#include <asm/pci-bridge.h>
+#include <asm/prom.h>
+#include <asm/rtas.h>
+
+struct eeh_rmv_data {
+ struct list_head removed_vf_list;
+ int removed_dev_count;
+};
+
+static int eeh_result_priority(enum pci_ers_result result)
+{
+ switch (result) {
+ case PCI_ERS_RESULT_NONE:
+ return 1;
+ case PCI_ERS_RESULT_NO_AER_DRIVER:
+ return 2;
+ case PCI_ERS_RESULT_RECOVERED:
+ return 3;
+ case PCI_ERS_RESULT_CAN_RECOVER:
+ return 4;
+ case PCI_ERS_RESULT_DISCONNECT:
+ return 5;
+ case PCI_ERS_RESULT_NEED_RESET:
+ return 6;
+ default:
+ WARN_ONCE(1, "Unknown pci_ers_result value: %d\n", (int)result);
+ return 0;
+ }
+};
+
+static const char *pci_ers_result_name(enum pci_ers_result result)
+{
+ switch (result) {
+ case PCI_ERS_RESULT_NONE:
+ return "none";
+ case PCI_ERS_RESULT_CAN_RECOVER:
+ return "can recover";
+ case PCI_ERS_RESULT_NEED_RESET:
+ return "need reset";
+ case PCI_ERS_RESULT_DISCONNECT:
+ return "disconnect";
+ case PCI_ERS_RESULT_RECOVERED:
+ return "recovered";
+ case PCI_ERS_RESULT_NO_AER_DRIVER:
+ return "no AER driver";
+ default:
+ WARN_ONCE(1, "Unknown result type: %d\n", (int)result);
+ return "unknown";
+ }
+};
+
+static enum pci_ers_result pci_ers_merge_result(enum pci_ers_result old,
+ enum pci_ers_result new)
+{
+ if (eeh_result_priority(new) > eeh_result_priority(old))
+ return new;
+ return old;
+}
+
+static bool eeh_dev_removed(struct eeh_dev *edev)
+{
+ return !edev || (edev->mode & EEH_DEV_REMOVED);
+}
+
+static bool eeh_edev_actionable(struct eeh_dev *edev)
+{
+ if (!edev->pdev)
+ return false;
+ if (edev->pdev->error_state == pci_channel_io_perm_failure)
+ return false;
+ if (eeh_dev_removed(edev))
+ return false;
+ if (eeh_pe_passed(edev->pe))
+ return false;
+
+ return true;
+}
+
+/**
+ * eeh_pcid_get - Get the PCI device driver
+ * @pdev: PCI device
+ *
+ * The function is used to retrieve the PCI device driver for
+ * the indicated PCI device. Besides, we will increase the reference
+ * of the PCI device driver to prevent that being unloaded on
+ * the fly. Otherwise, kernel crash would be seen.
+ */
+static inline struct pci_driver *eeh_pcid_get(struct pci_dev *pdev)
+{
+ if (!pdev || !pdev->driver)
+ return NULL;
+
+ if (!try_module_get(pdev->driver->driver.owner))
+ return NULL;
+
+ return pdev->driver;
+}
+
+/**
+ * eeh_pcid_put - Dereference on the PCI device driver
+ * @pdev: PCI device
+ *
+ * The function is called to do dereference on the PCI device
+ * driver of the indicated PCI device.
+ */
+static inline void eeh_pcid_put(struct pci_dev *pdev)
+{
+ if (!pdev || !pdev->driver)
+ return;
+
+ module_put(pdev->driver->driver.owner);
+}
+
+/**
+ * eeh_disable_irq - Disable interrupt for the recovering device
+ * @dev: PCI device
+ *
+ * This routine must be called when reporting temporary or permanent
+ * error to the particular PCI device to disable interrupt of that
+ * device. If the device has enabled MSI or MSI-X interrupt, we needn't
+ * do real work because EEH should freeze DMA transfers for those PCI
+ * devices encountering EEH errors, which includes MSI or MSI-X.
+ */
+static void eeh_disable_irq(struct eeh_dev *edev)
+{
+ /* Don't disable MSI and MSI-X interrupts. They are
+ * effectively disabled by the DMA Stopped state
+ * when an EEH error occurs.
+ */
+ if (edev->pdev->msi_enabled || edev->pdev->msix_enabled)
+ return;
+
+ if (!irq_has_action(edev->pdev->irq))
+ return;
+
+ edev->mode |= EEH_DEV_IRQ_DISABLED;
+ disable_irq_nosync(edev->pdev->irq);
+}
+
+/**
+ * eeh_enable_irq - Enable interrupt for the recovering device
+ * @dev: PCI device
+ *
+ * This routine must be called to enable interrupt while failed
+ * device could be resumed.
+ */
+static void eeh_enable_irq(struct eeh_dev *edev)
+{
+ if ((edev->mode) & EEH_DEV_IRQ_DISABLED) {
+ edev->mode &= ~EEH_DEV_IRQ_DISABLED;
+ /*
+ * FIXME !!!!!
+ *
+ * This is just ass backwards. This maze has
+ * unbalanced irq_enable/disable calls. So instead of
+ * finding the root cause it works around the warning
+ * in the irq_enable code by conditionally calling
+ * into it.
+ *
+ * That's just wrong.The warning in the core code is
+ * there to tell people to fix their asymmetries in
+ * their own code, not by abusing the core information
+ * to avoid it.
+ *
+ * I so wish that the assymetry would be the other way
+ * round and a few more irq_disable calls render that
+ * shit unusable forever.
+ *
+ * tglx
+ */
+ if (irqd_irq_disabled(irq_get_irq_data(edev->pdev->irq)))
+ enable_irq(edev->pdev->irq);
+ }
+}
+
+static void eeh_dev_save_state(struct eeh_dev *edev, void *userdata)
+{
+ struct pci_dev *pdev;
+
+ if (!edev)
+ return;
+
+ /*
+ * We cannot access the config space on some adapters.
+ * Otherwise, it will cause fenced PHB. We don't save
+ * the content in their config space and will restore
+ * from the initial config space saved when the EEH
+ * device is created.
+ */
+ if (edev->pe && (edev->pe->state & EEH_PE_CFG_RESTRICTED))
+ return;
+
+ pdev = eeh_dev_to_pci_dev(edev);
+ if (!pdev)
+ return;
+
+ pci_save_state(pdev);
+}
+
+static void eeh_set_channel_state(struct eeh_pe *root, pci_channel_state_t s)
+{
+ struct eeh_pe *pe;
+ struct eeh_dev *edev, *tmp;
+
+ eeh_for_each_pe(root, pe)
+ eeh_pe_for_each_dev(pe, edev, tmp)
+ if (eeh_edev_actionable(edev))
+ edev->pdev->error_state = s;
+}
+
+static void eeh_set_irq_state(struct eeh_pe *root, bool enable)
+{
+ struct eeh_pe *pe;
+ struct eeh_dev *edev, *tmp;
+
+ eeh_for_each_pe(root, pe) {
+ eeh_pe_for_each_dev(pe, edev, tmp) {
+ if (!eeh_edev_actionable(edev))
+ continue;
+
+ if (!eeh_pcid_get(edev->pdev))
+ continue;
+
+ if (enable)
+ eeh_enable_irq(edev);
+ else
+ eeh_disable_irq(edev);
+
+ eeh_pcid_put(edev->pdev);
+ }
+ }
+}
+
+typedef enum pci_ers_result (*eeh_report_fn)(struct eeh_dev *,
+ struct pci_dev *,
+ struct pci_driver *);
+static void eeh_pe_report_edev(struct eeh_dev *edev, eeh_report_fn fn,
+ enum pci_ers_result *result)
+{
+ struct pci_dev *pdev;
+ struct pci_driver *driver;
+ enum pci_ers_result new_result;
+
+ pci_lock_rescan_remove();
+ pdev = edev->pdev;
+ if (pdev)
+ get_device(&pdev->dev);
+ pci_unlock_rescan_remove();
+ if (!pdev) {
+ eeh_edev_info(edev, "no device");
+ return;
+ }
+ device_lock(&pdev->dev);
+ if (eeh_edev_actionable(edev)) {
+ driver = eeh_pcid_get(pdev);
+
+ if (!driver)
+ eeh_edev_info(edev, "no driver");
+ else if (!driver->err_handler)
+ eeh_edev_info(edev, "driver not EEH aware");
+ else if (edev->mode & EEH_DEV_NO_HANDLER)
+ eeh_edev_info(edev, "driver bound too late");
+ else {
+ new_result = fn(edev, pdev, driver);
+ eeh_edev_info(edev, "%s driver reports: '%s'",
+ driver->name,
+ pci_ers_result_name(new_result));
+ if (result)
+ *result = pci_ers_merge_result(*result,
+ new_result);
+ }
+ if (driver)
+ eeh_pcid_put(pdev);
+ } else {
+ eeh_edev_info(edev, "not actionable (%d,%d,%d)", !!pdev,
+ !eeh_dev_removed(edev), !eeh_pe_passed(edev->pe));
+ }
+ device_unlock(&pdev->dev);
+ if (edev->pdev != pdev)
+ eeh_edev_warn(edev, "Device changed during processing!\n");
+ put_device(&pdev->dev);
+}
+
+static void eeh_pe_report(const char *name, struct eeh_pe *root,
+ eeh_report_fn fn, enum pci_ers_result *result)
+{
+ struct eeh_pe *pe;
+ struct eeh_dev *edev, *tmp;
+
+ pr_info("EEH: Beginning: '%s'\n", name);
+ eeh_for_each_pe(root, pe) eeh_pe_for_each_dev(pe, edev, tmp)
+ eeh_pe_report_edev(edev, fn, result);
+ if (result)
+ pr_info("EEH: Finished:'%s' with aggregate recovery state:'%s'\n",
+ name, pci_ers_result_name(*result));
+ else
+ pr_info("EEH: Finished:'%s'", name);
+}
+
+/**
+ * eeh_report_error - Report pci error to each device driver
+ * @edev: eeh device
+ * @driver: device's PCI driver
+ *
+ * Report an EEH error to each device driver.
+ */
+static enum pci_ers_result eeh_report_error(struct eeh_dev *edev,
+ struct pci_dev *pdev,
+ struct pci_driver *driver)
+{
+ enum pci_ers_result rc;
+
+ if (!driver->err_handler->error_detected)
+ return PCI_ERS_RESULT_NONE;
+
+ eeh_edev_info(edev, "Invoking %s->error_detected(IO frozen)",
+ driver->name);
+ rc = driver->err_handler->error_detected(pdev, pci_channel_io_frozen);
+
+ edev->in_error = true;
+ pci_uevent_ers(pdev, PCI_ERS_RESULT_NONE);
+ return rc;
+}
+
+/**
+ * eeh_report_mmio_enabled - Tell drivers that MMIO has been enabled
+ * @edev: eeh device
+ * @driver: device's PCI driver
+ *
+ * Tells each device driver that IO ports, MMIO and config space I/O
+ * are now enabled.
+ */
+static enum pci_ers_result eeh_report_mmio_enabled(struct eeh_dev *edev,
+ struct pci_dev *pdev,
+ struct pci_driver *driver)
+{
+ if (!driver->err_handler->mmio_enabled)
+ return PCI_ERS_RESULT_NONE;
+ eeh_edev_info(edev, "Invoking %s->mmio_enabled()", driver->name);
+ return driver->err_handler->mmio_enabled(pdev);
+}
+
+/**
+ * eeh_report_reset - Tell device that slot has been reset
+ * @edev: eeh device
+ * @driver: device's PCI driver
+ *
+ * This routine must be called while EEH tries to reset particular
+ * PCI device so that the associated PCI device driver could take
+ * some actions, usually to save data the driver needs so that the
+ * driver can work again while the device is recovered.
+ */
+static enum pci_ers_result eeh_report_reset(struct eeh_dev *edev,
+ struct pci_dev *pdev,
+ struct pci_driver *driver)
+{
+ if (!driver->err_handler->slot_reset || !edev->in_error)
+ return PCI_ERS_RESULT_NONE;
+ eeh_edev_info(edev, "Invoking %s->slot_reset()", driver->name);
+ return driver->err_handler->slot_reset(pdev);
+}
+
+static void eeh_dev_restore_state(struct eeh_dev *edev, void *userdata)
+{
+ struct pci_dev *pdev;
+
+ if (!edev)
+ return;
+
+ /*
+ * The content in the config space isn't saved because
+ * the blocked config space on some adapters. We have
+ * to restore the initial saved config space when the
+ * EEH device is created.
+ */
+ if (edev->pe && (edev->pe->state & EEH_PE_CFG_RESTRICTED)) {
+ if (list_is_last(&edev->entry, &edev->pe->edevs))
+ eeh_pe_restore_bars(edev->pe);
+
+ return;
+ }
+
+ pdev = eeh_dev_to_pci_dev(edev);
+ if (!pdev)
+ return;
+
+ pci_restore_state(pdev);
+}
+
+/**
+ * eeh_report_resume - Tell device to resume normal operations
+ * @edev: eeh device
+ * @driver: device's PCI driver
+ *
+ * This routine must be called to notify the device driver that it
+ * could resume so that the device driver can do some initialization
+ * to make the recovered device work again.
+ */
+static enum pci_ers_result eeh_report_resume(struct eeh_dev *edev,
+ struct pci_dev *pdev,
+ struct pci_driver *driver)
+{
+ if (!driver->err_handler->resume || !edev->in_error)
+ return PCI_ERS_RESULT_NONE;
+
+ eeh_edev_info(edev, "Invoking %s->resume()", driver->name);
+ driver->err_handler->resume(pdev);
+
+ pci_uevent_ers(edev->pdev, PCI_ERS_RESULT_RECOVERED);
+#ifdef CONFIG_PCI_IOV
+ if (eeh_ops->notify_resume)
+ eeh_ops->notify_resume(edev);
+#endif
+ return PCI_ERS_RESULT_NONE;
+}
+
+/**
+ * eeh_report_failure - Tell device driver that device is dead.
+ * @edev: eeh device
+ * @driver: device's PCI driver
+ *
+ * This informs the device driver that the device is permanently
+ * dead, and that no further recovery attempts will be made on it.
+ */
+static enum pci_ers_result eeh_report_failure(struct eeh_dev *edev,
+ struct pci_dev *pdev,
+ struct pci_driver *driver)
+{
+ enum pci_ers_result rc;
+
+ if (!driver->err_handler->error_detected)
+ return PCI_ERS_RESULT_NONE;
+
+ eeh_edev_info(edev, "Invoking %s->error_detected(permanent failure)",
+ driver->name);
+ rc = driver->err_handler->error_detected(pdev,
+ pci_channel_io_perm_failure);
+
+ pci_uevent_ers(pdev, PCI_ERS_RESULT_DISCONNECT);
+ return rc;
+}
+
+static void *eeh_add_virt_device(struct eeh_dev *edev)
+{
+ struct pci_driver *driver;
+ struct pci_dev *dev = eeh_dev_to_pci_dev(edev);
+
+ if (!(edev->physfn)) {
+ eeh_edev_warn(edev, "Not for VF\n");
+ return NULL;
+ }
+
+ driver = eeh_pcid_get(dev);
+ if (driver) {
+ if (driver->err_handler) {
+ eeh_pcid_put(dev);
+ return NULL;
+ }
+ eeh_pcid_put(dev);
+ }
+
+#ifdef CONFIG_PCI_IOV
+ pci_iov_add_virtfn(edev->physfn, edev->vf_index);
+#endif
+ return NULL;
+}
+
+static void eeh_rmv_device(struct eeh_dev *edev, void *userdata)
+{
+ struct pci_driver *driver;
+ struct pci_dev *dev = eeh_dev_to_pci_dev(edev);
+ struct eeh_rmv_data *rmv_data = (struct eeh_rmv_data *)userdata;
+
+ /*
+ * Actually, we should remove the PCI bridges as well.
+ * However, that's lots of complexity to do that,
+ * particularly some of devices under the bridge might
+ * support EEH. So we just care about PCI devices for
+ * simplicity here.
+ */
+ if (!eeh_edev_actionable(edev) ||
+ (dev->hdr_type == PCI_HEADER_TYPE_BRIDGE))
+ return;
+
+ if (rmv_data) {
+ driver = eeh_pcid_get(dev);
+ if (driver) {
+ if (driver->err_handler &&
+ driver->err_handler->error_detected &&
+ driver->err_handler->slot_reset) {
+ eeh_pcid_put(dev);
+ return;
+ }
+ eeh_pcid_put(dev);
+ }
+ }
+
+ /* Remove it from PCI subsystem */
+ pr_info("EEH: Removing %s without EEH sensitive driver\n",
+ pci_name(dev));
+ edev->mode |= EEH_DEV_DISCONNECTED;
+ if (rmv_data)
+ rmv_data->removed_dev_count++;
+
+ if (edev->physfn) {
+#ifdef CONFIG_PCI_IOV
+ pci_iov_remove_virtfn(edev->physfn, edev->vf_index);
+ edev->pdev = NULL;
+#endif
+ if (rmv_data)
+ list_add(&edev->rmv_entry, &rmv_data->removed_vf_list);
+ } else {
+ pci_lock_rescan_remove();
+ pci_stop_and_remove_bus_device(dev);
+ pci_unlock_rescan_remove();
+ }
+}
+
+static void *eeh_pe_detach_dev(struct eeh_pe *pe, void *userdata)
+{
+ struct eeh_dev *edev, *tmp;
+
+ eeh_pe_for_each_dev(pe, edev, tmp) {
+ if (!(edev->mode & EEH_DEV_DISCONNECTED))
+ continue;
+
+ edev->mode &= ~(EEH_DEV_DISCONNECTED | EEH_DEV_IRQ_DISABLED);
+ eeh_pe_tree_remove(edev);
+ }
+
+ return NULL;
+}
+
+/*
+ * Explicitly clear PE's frozen state for PowerNV where
+ * we have frozen PE until BAR restore is completed. It's
+ * harmless to clear it for pSeries. To be consistent with
+ * PE reset (for 3 times), we try to clear the frozen state
+ * for 3 times as well.
+ */
+static int eeh_clear_pe_frozen_state(struct eeh_pe *root, bool include_passed)
+{
+ struct eeh_pe *pe;
+ int i;
+
+ eeh_for_each_pe(root, pe) {
+ if (include_passed || !eeh_pe_passed(pe)) {
+ for (i = 0; i < 3; i++)
+ if (!eeh_unfreeze_pe(pe))
+ break;
+ if (i >= 3)
+ return -EIO;
+ }
+ }
+ eeh_pe_state_clear(root, EEH_PE_ISOLATED, include_passed);
+ return 0;
+}
+
+int eeh_pe_reset_and_recover(struct eeh_pe *pe)
+{
+ int ret;
+
+ /* Bail if the PE is being recovered */
+ if (pe->state & EEH_PE_RECOVERING)
+ return 0;
+
+ /* Put the PE into recovery mode */
+ eeh_pe_state_mark(pe, EEH_PE_RECOVERING);
+
+ /* Save states */
+ eeh_pe_dev_traverse(pe, eeh_dev_save_state, NULL);
+
+ /* Issue reset */
+ ret = eeh_pe_reset_full(pe, true);
+ if (ret) {
+ eeh_pe_state_clear(pe, EEH_PE_RECOVERING, true);
+ return ret;
+ }
+
+ /* Unfreeze the PE */
+ ret = eeh_clear_pe_frozen_state(pe, true);
+ if (ret) {
+ eeh_pe_state_clear(pe, EEH_PE_RECOVERING, true);
+ return ret;
+ }
+
+ /* Restore device state */
+ eeh_pe_dev_traverse(pe, eeh_dev_restore_state, NULL);
+
+ /* Clear recovery mode */
+ eeh_pe_state_clear(pe, EEH_PE_RECOVERING, true);
+
+ return 0;
+}
+
+/**
+ * eeh_reset_device - Perform actual reset of a pci slot
+ * @driver_eeh_aware: Does the device's driver provide EEH support?
+ * @pe: EEH PE
+ * @bus: PCI bus corresponding to the isolcated slot
+ * @rmv_data: Optional, list to record removed devices
+ *
+ * This routine must be called to do reset on the indicated PE.
+ * During the reset, udev might be invoked because those affected
+ * PCI devices will be removed and then added.
+ */
+static int eeh_reset_device(struct eeh_pe *pe, struct pci_bus *bus,
+ struct eeh_rmv_data *rmv_data,
+ bool driver_eeh_aware)
+{
+ time64_t tstamp;
+ int cnt, rc;
+ struct eeh_dev *edev;
+ struct eeh_pe *tmp_pe;
+ bool any_passed = false;
+
+ eeh_for_each_pe(pe, tmp_pe)
+ any_passed |= eeh_pe_passed(tmp_pe);
+
+ /* pcibios will clear the counter; save the value */
+ cnt = pe->freeze_count;
+ tstamp = pe->tstamp;
+
+ /*
+ * We don't remove the corresponding PE instances because
+ * we need the information afterwords. The attached EEH
+ * devices are expected to be attached soon when calling
+ * into pci_hp_add_devices().
+ */
+ eeh_pe_state_mark(pe, EEH_PE_KEEP);
+ if (any_passed || driver_eeh_aware || (pe->type & EEH_PE_VF)) {
+ eeh_pe_dev_traverse(pe, eeh_rmv_device, rmv_data);
+ } else {
+ pci_lock_rescan_remove();
+ pci_hp_remove_devices(bus);
+ pci_unlock_rescan_remove();
+ }
+
+ /*
+ * Reset the pci controller. (Asserts RST#; resets config space).
+ * Reconfigure bridges and devices. Don't try to bring the system
+ * up if the reset failed for some reason.
+ *
+ * During the reset, it's very dangerous to have uncontrolled PCI
+ * config accesses. So we prefer to block them. However, controlled
+ * PCI config accesses initiated from EEH itself are allowed.
+ */
+ rc = eeh_pe_reset_full(pe, false);
+ if (rc)
+ return rc;
+
+ pci_lock_rescan_remove();
+
+ /* Restore PE */
+ eeh_ops->configure_bridge(pe);
+ eeh_pe_restore_bars(pe);
+
+ /* Clear frozen state */
+ rc = eeh_clear_pe_frozen_state(pe, false);
+ if (rc) {
+ pci_unlock_rescan_remove();
+ return rc;
+ }
+
+ /* Give the system 5 seconds to finish running the user-space
+ * hotplug shutdown scripts, e.g. ifdown for ethernet. Yes,
+ * this is a hack, but if we don't do this, and try to bring
+ * the device up before the scripts have taken it down,
+ * potentially weird things happen.
+ */
+ if (!driver_eeh_aware || rmv_data->removed_dev_count) {
+ pr_info("EEH: Sleep 5s ahead of %s hotplug\n",
+ (driver_eeh_aware ? "partial" : "complete"));
+ ssleep(5);
+
+ /*
+ * The EEH device is still connected with its parent
+ * PE. We should disconnect it so the binding can be
+ * rebuilt when adding PCI devices.
+ */
+ edev = list_first_entry(&pe->edevs, struct eeh_dev, entry);
+ eeh_pe_traverse(pe, eeh_pe_detach_dev, NULL);
+ if (pe->type & EEH_PE_VF) {
+ eeh_add_virt_device(edev);
+ } else {
+ if (!driver_eeh_aware)
+ eeh_pe_state_clear(pe, EEH_PE_PRI_BUS, true);
+ pci_hp_add_devices(bus);
+ }
+ }
+ eeh_pe_state_clear(pe, EEH_PE_KEEP, true);
+
+ pe->tstamp = tstamp;
+ pe->freeze_count = cnt;
+
+ pci_unlock_rescan_remove();
+ return 0;
+}
+
+/* The longest amount of time to wait for a pci device
+ * to come back on line, in seconds.
+ */
+#define MAX_WAIT_FOR_RECOVERY 300
+
+
+/* Walks the PE tree after processing an event to remove any stale PEs.
+ *
+ * NB: This needs to be recursive to ensure the leaf PEs get removed
+ * before their parents do. Although this is possible to do recursively
+ * we don't since this is easier to read and we need to garantee
+ * the leaf nodes will be handled first.
+ */
+static void eeh_pe_cleanup(struct eeh_pe *pe)
+{
+ struct eeh_pe *child_pe, *tmp;
+
+ list_for_each_entry_safe(child_pe, tmp, &pe->child_list, child)
+ eeh_pe_cleanup(child_pe);
+
+ if (pe->state & EEH_PE_KEEP)
+ return;
+
+ if (!(pe->state & EEH_PE_INVALID))
+ return;
+
+ if (list_empty(&pe->edevs) && list_empty(&pe->child_list)) {
+ list_del(&pe->child);
+ kfree(pe);
+ }
+}
+
+/**
+ * eeh_check_slot_presence - Check if a device is still present in a slot
+ * @pdev: pci_dev to check
+ *
+ * This function may return a false positive if we can't determine the slot's
+ * presence state. This might happen for for PCIe slots if the PE containing
+ * the upstream bridge is also frozen, or the bridge is part of the same PE
+ * as the device.
+ *
+ * This shouldn't happen often, but you might see it if you hotplug a PCIe
+ * switch.
+ */
+static bool eeh_slot_presence_check(struct pci_dev *pdev)
+{
+ const struct hotplug_slot_ops *ops;
+ struct pci_slot *slot;
+ u8 state;
+ int rc;
+
+ if (!pdev)
+ return false;
+
+ if (pdev->error_state == pci_channel_io_perm_failure)
+ return false;
+
+ slot = pdev->slot;
+ if (!slot || !slot->hotplug)
+ return true;
+
+ ops = slot->hotplug->ops;
+ if (!ops || !ops->get_adapter_status)
+ return true;
+
+ /* set the attention indicator while we've got the slot ops */
+ if (ops->set_attention_status)
+ ops->set_attention_status(slot->hotplug, 1);
+
+ rc = ops->get_adapter_status(slot->hotplug, &state);
+ if (rc)
+ return true;
+
+ return !!state;
+}
+
+static void eeh_clear_slot_attention(struct pci_dev *pdev)
+{
+ const struct hotplug_slot_ops *ops;
+ struct pci_slot *slot;
+
+ if (!pdev)
+ return;
+
+ if (pdev->error_state == pci_channel_io_perm_failure)
+ return;
+
+ slot = pdev->slot;
+ if (!slot || !slot->hotplug)
+ return;
+
+ ops = slot->hotplug->ops;
+ if (!ops || !ops->set_attention_status)
+ return;
+
+ ops->set_attention_status(slot->hotplug, 0);
+}
+
+/**
+ * eeh_handle_normal_event - Handle EEH events on a specific PE
+ * @pe: EEH PE - which should not be used after we return, as it may
+ * have been invalidated.
+ *
+ * Attempts to recover the given PE. If recovery fails or the PE has failed
+ * too many times, remove the PE.
+ *
+ * While PHB detects address or data parity errors on particular PCI
+ * slot, the associated PE will be frozen. Besides, DMA's occurring
+ * to wild addresses (which usually happen due to bugs in device
+ * drivers or in PCI adapter firmware) can cause EEH error. #SERR,
+ * #PERR or other misc PCI-related errors also can trigger EEH errors.
+ *
+ * Recovery process consists of unplugging the device driver (which
+ * generated hotplug events to userspace), then issuing a PCI #RST to
+ * the device, then reconfiguring the PCI config space for all bridges
+ * & devices under this slot, and then finally restarting the device
+ * drivers (which cause a second set of hotplug events to go out to
+ * userspace).
+ */
+void eeh_handle_normal_event(struct eeh_pe *pe)
+{
+ struct pci_bus *bus;
+ struct eeh_dev *edev, *tmp;
+ struct eeh_pe *tmp_pe;
+ int rc = 0;
+ enum pci_ers_result result = PCI_ERS_RESULT_NONE;
+ struct eeh_rmv_data rmv_data =
+ {LIST_HEAD_INIT(rmv_data.removed_vf_list), 0};
+ int devices = 0;
+
+ bus = eeh_pe_bus_get(pe);
+ if (!bus) {
+ pr_err("%s: Cannot find PCI bus for PHB#%x-PE#%x\n",
+ __func__, pe->phb->global_number, pe->addr);
+ return;
+ }
+
+ /*
+ * When devices are hot-removed we might get an EEH due to
+ * a driver attempting to touch the MMIO space of a removed
+ * device. In this case we don't have a device to recover
+ * so suppress the event if we can't find any present devices.
+ *
+ * The hotplug driver should take care of tearing down the
+ * device itself.
+ */
+ eeh_for_each_pe(pe, tmp_pe)
+ eeh_pe_for_each_dev(tmp_pe, edev, tmp)
+ if (eeh_slot_presence_check(edev->pdev))
+ devices++;
+
+ if (!devices) {
+ pr_debug("EEH: Frozen PHB#%x-PE#%x is empty!\n",
+ pe->phb->global_number, pe->addr);
+ goto out; /* nothing to recover */
+ }
+
+ /* Log the event */
+ if (pe->type & EEH_PE_PHB) {
+ pr_err("EEH: Recovering PHB#%x, location: %s\n",
+ pe->phb->global_number, eeh_pe_loc_get(pe));
+ } else {
+ struct eeh_pe *phb_pe = eeh_phb_pe_get(pe->phb);
+
+ pr_err("EEH: Recovering PHB#%x-PE#%x\n",
+ pe->phb->global_number, pe->addr);
+ pr_err("EEH: PE location: %s, PHB location: %s\n",
+ eeh_pe_loc_get(pe), eeh_pe_loc_get(phb_pe));
+ }
+
+#ifdef CONFIG_STACKTRACE
+ /*
+ * Print the saved stack trace now that we've verified there's
+ * something to recover.
+ */
+ if (pe->trace_entries) {
+ void **ptrs = (void **) pe->stack_trace;
+ int i;
+
+ pr_err("EEH: Frozen PHB#%x-PE#%x detected\n",
+ pe->phb->global_number, pe->addr);
+
+ /* FIXME: Use the same format as dump_stack() */
+ pr_err("EEH: Call Trace:\n");
+ for (i = 0; i < pe->trace_entries; i++)
+ pr_err("EEH: [%pK] %pS\n", ptrs[i], ptrs[i]);
+
+ pe->trace_entries = 0;
+ }
+#endif /* CONFIG_STACKTRACE */
+
+ eeh_pe_update_time_stamp(pe);
+ pe->freeze_count++;
+ if (pe->freeze_count > eeh_max_freezes) {
+ pr_err("EEH: PHB#%x-PE#%x has failed %d times in the last hour and has been permanently disabled.\n",
+ pe->phb->global_number, pe->addr,
+ pe->freeze_count);
+ result = PCI_ERS_RESULT_DISCONNECT;
+ }
+
+ eeh_for_each_pe(pe, tmp_pe)
+ eeh_pe_for_each_dev(tmp_pe, edev, tmp)
+ edev->mode &= ~EEH_DEV_NO_HANDLER;
+
+ /* Walk the various device drivers attached to this slot through
+ * a reset sequence, giving each an opportunity to do what it needs
+ * to accomplish the reset. Each child gets a report of the
+ * status ... if any child can't handle the reset, then the entire
+ * slot is dlpar removed and added.
+ *
+ * When the PHB is fenced, we have to issue a reset to recover from
+ * the error. Override the result if necessary to have partially
+ * hotplug for this case.
+ */
+ if (result != PCI_ERS_RESULT_DISCONNECT) {
+ pr_warn("EEH: This PCI device has failed %d times in the last hour and will be permanently disabled after %d failures.\n",
+ pe->freeze_count, eeh_max_freezes);
+ pr_info("EEH: Notify device drivers to shutdown\n");
+ eeh_set_channel_state(pe, pci_channel_io_frozen);
+ eeh_set_irq_state(pe, false);
+ eeh_pe_report("error_detected(IO frozen)", pe,
+ eeh_report_error, &result);
+ if ((pe->type & EEH_PE_PHB) &&
+ result != PCI_ERS_RESULT_NONE &&
+ result != PCI_ERS_RESULT_NEED_RESET)
+ result = PCI_ERS_RESULT_NEED_RESET;
+ }
+
+ /* Get the current PCI slot state. This can take a long time,
+ * sometimes over 300 seconds for certain systems.
+ */
+ if (result != PCI_ERS_RESULT_DISCONNECT) {
+ rc = eeh_wait_state(pe, MAX_WAIT_FOR_RECOVERY*1000);
+ if (rc < 0 || rc == EEH_STATE_NOT_SUPPORT) {
+ pr_warn("EEH: Permanent failure\n");
+ result = PCI_ERS_RESULT_DISCONNECT;
+ }
+ }
+
+ /* Since rtas may enable MMIO when posting the error log,
+ * don't post the error log until after all dev drivers
+ * have been informed.
+ */
+ if (result != PCI_ERS_RESULT_DISCONNECT) {
+ pr_info("EEH: Collect temporary log\n");
+ eeh_slot_error_detail(pe, EEH_LOG_TEMP);
+ }
+
+ /* If all device drivers were EEH-unaware, then shut
+ * down all of the device drivers, and hope they
+ * go down willingly, without panicing the system.
+ */
+ if (result == PCI_ERS_RESULT_NONE) {
+ pr_info("EEH: Reset with hotplug activity\n");
+ rc = eeh_reset_device(pe, bus, NULL, false);
+ if (rc) {
+ pr_warn("%s: Unable to reset, err=%d\n",
+ __func__, rc);
+ result = PCI_ERS_RESULT_DISCONNECT;
+ }
+ }
+
+ /* If all devices reported they can proceed, then re-enable MMIO */
+ if (result == PCI_ERS_RESULT_CAN_RECOVER) {
+ pr_info("EEH: Enable I/O for affected devices\n");
+ rc = eeh_pci_enable(pe, EEH_OPT_THAW_MMIO);
+
+ if (rc < 0) {
+ result = PCI_ERS_RESULT_DISCONNECT;
+ } else if (rc) {
+ result = PCI_ERS_RESULT_NEED_RESET;
+ } else {
+ pr_info("EEH: Notify device drivers to resume I/O\n");
+ eeh_pe_report("mmio_enabled", pe,
+ eeh_report_mmio_enabled, &result);
+ }
+ }
+
+ /* If all devices reported they can proceed, then re-enable DMA */
+ if (result == PCI_ERS_RESULT_CAN_RECOVER) {
+ pr_info("EEH: Enabled DMA for affected devices\n");
+ rc = eeh_pci_enable(pe, EEH_OPT_THAW_DMA);
+
+ if (rc < 0) {
+ result = PCI_ERS_RESULT_DISCONNECT;
+ } else if (rc) {
+ result = PCI_ERS_RESULT_NEED_RESET;
+ } else {
+ /*
+ * We didn't do PE reset for the case. The PE
+ * is still in frozen state. Clear it before
+ * resuming the PE.
+ */
+ eeh_pe_state_clear(pe, EEH_PE_ISOLATED, true);
+ result = PCI_ERS_RESULT_RECOVERED;
+ }
+ }
+
+ /* If any device called out for a reset, then reset the slot */
+ if (result == PCI_ERS_RESULT_NEED_RESET) {
+ pr_info("EEH: Reset without hotplug activity\n");
+ rc = eeh_reset_device(pe, bus, &rmv_data, true);
+ if (rc) {
+ pr_warn("%s: Cannot reset, err=%d\n",
+ __func__, rc);
+ result = PCI_ERS_RESULT_DISCONNECT;
+ } else {
+ result = PCI_ERS_RESULT_NONE;
+ eeh_set_channel_state(pe, pci_channel_io_normal);
+ eeh_set_irq_state(pe, true);
+ eeh_pe_report("slot_reset", pe, eeh_report_reset,
+ &result);
+ }
+ }
+
+ if ((result == PCI_ERS_RESULT_RECOVERED) ||
+ (result == PCI_ERS_RESULT_NONE)) {
+ /*
+ * For those hot removed VFs, we should add back them after PF
+ * get recovered properly.
+ */
+ list_for_each_entry_safe(edev, tmp, &rmv_data.removed_vf_list,
+ rmv_entry) {
+ eeh_add_virt_device(edev);
+ list_del(&edev->rmv_entry);
+ }
+
+ /* Tell all device drivers that they can resume operations */
+ pr_info("EEH: Notify device driver to resume\n");
+ eeh_set_channel_state(pe, pci_channel_io_normal);
+ eeh_set_irq_state(pe, true);
+ eeh_pe_report("resume", pe, eeh_report_resume, NULL);
+ eeh_for_each_pe(pe, tmp_pe) {
+ eeh_pe_for_each_dev(tmp_pe, edev, tmp) {
+ edev->mode &= ~EEH_DEV_NO_HANDLER;
+ edev->in_error = false;
+ }
+ }
+
+ pr_info("EEH: Recovery successful.\n");
+ goto out;
+ }
+
+ /*
+ * About 90% of all real-life EEH failures in the field
+ * are due to poorly seated PCI cards. Only 10% or so are
+ * due to actual, failed cards.
+ */
+ pr_err("EEH: Unable to recover from failure from PHB#%x-PE#%x.\n"
+ "Please try reseating or replacing it\n",
+ pe->phb->global_number, pe->addr);
+
+ eeh_slot_error_detail(pe, EEH_LOG_PERM);
+
+ /* Notify all devices that they're about to go down. */
+ eeh_set_irq_state(pe, false);
+ eeh_pe_report("error_detected(permanent failure)", pe,
+ eeh_report_failure, NULL);
+ eeh_set_channel_state(pe, pci_channel_io_perm_failure);
+
+ /* Mark the PE to be removed permanently */
+ eeh_pe_state_mark(pe, EEH_PE_REMOVED);
+
+ /*
+ * Shut down the device drivers for good. We mark
+ * all removed devices correctly to avoid access
+ * the their PCI config any more.
+ */
+ if (pe->type & EEH_PE_VF) {
+ eeh_pe_dev_traverse(pe, eeh_rmv_device, NULL);
+ eeh_pe_dev_mode_mark(pe, EEH_DEV_REMOVED);
+ } else {
+ eeh_pe_state_clear(pe, EEH_PE_PRI_BUS, true);
+ eeh_pe_dev_mode_mark(pe, EEH_DEV_REMOVED);
+
+ pci_lock_rescan_remove();
+ pci_hp_remove_devices(bus);
+ pci_unlock_rescan_remove();
+ /* The passed PE should no longer be used */
+ return;
+ }
+
+out:
+ /*
+ * Clean up any PEs without devices. While marked as EEH_PE_RECOVERYING
+ * we don't want to modify the PE tree structure so we do it here.
+ */
+ eeh_pe_cleanup(pe);
+
+ /* clear the slot attention LED for all recovered devices */
+ eeh_for_each_pe(pe, tmp_pe)
+ eeh_pe_for_each_dev(tmp_pe, edev, tmp)
+ eeh_clear_slot_attention(edev->pdev);
+
+ eeh_pe_state_clear(pe, EEH_PE_RECOVERING, true);
+}
+
+/**
+ * eeh_handle_special_event - Handle EEH events without a specific failing PE
+ *
+ * Called when an EEH event is detected but can't be narrowed down to a
+ * specific PE. Iterates through possible failures and handles them as
+ * necessary.
+ */
+void eeh_handle_special_event(void)
+{
+ struct eeh_pe *pe, *phb_pe, *tmp_pe;
+ struct eeh_dev *edev, *tmp_edev;
+ struct pci_bus *bus;
+ struct pci_controller *hose;
+ unsigned long flags;
+ int rc;
+
+
+ do {
+ rc = eeh_ops->next_error(&pe);
+
+ switch (rc) {
+ case EEH_NEXT_ERR_DEAD_IOC:
+ /* Mark all PHBs in dead state */
+ eeh_serialize_lock(&flags);
+
+ /* Purge all events */
+ eeh_remove_event(NULL, true);
+
+ list_for_each_entry(hose, &hose_list, list_node) {
+ phb_pe = eeh_phb_pe_get(hose);
+ if (!phb_pe) continue;
+
+ eeh_pe_mark_isolated(phb_pe);
+ }
+
+ eeh_serialize_unlock(flags);
+
+ break;
+ case EEH_NEXT_ERR_FROZEN_PE:
+ case EEH_NEXT_ERR_FENCED_PHB:
+ case EEH_NEXT_ERR_DEAD_PHB:
+ /* Mark the PE in fenced state */
+ eeh_serialize_lock(&flags);
+
+ /* Purge all events of the PHB */
+ eeh_remove_event(pe, true);
+
+ if (rc != EEH_NEXT_ERR_DEAD_PHB)
+ eeh_pe_state_mark(pe, EEH_PE_RECOVERING);
+ eeh_pe_mark_isolated(pe);
+
+ eeh_serialize_unlock(flags);
+
+ break;
+ case EEH_NEXT_ERR_NONE:
+ return;
+ default:
+ pr_warn("%s: Invalid value %d from next_error()\n",
+ __func__, rc);
+ return;
+ }
+
+ /*
+ * For fenced PHB and frozen PE, it's handled as normal
+ * event. We have to remove the affected PHBs for dead
+ * PHB and IOC
+ */
+ if (rc == EEH_NEXT_ERR_FROZEN_PE ||
+ rc == EEH_NEXT_ERR_FENCED_PHB) {
+ eeh_pe_state_mark(pe, EEH_PE_RECOVERING);
+ eeh_handle_normal_event(pe);
+ } else {
+ eeh_for_each_pe(pe, tmp_pe)
+ eeh_pe_for_each_dev(tmp_pe, edev, tmp_edev)
+ edev->mode &= ~EEH_DEV_NO_HANDLER;
+
+ /* Notify all devices to be down */
+ eeh_pe_state_clear(pe, EEH_PE_PRI_BUS, true);
+ eeh_pe_report(
+ "error_detected(permanent failure)", pe,
+ eeh_report_failure, NULL);
+ eeh_set_channel_state(pe, pci_channel_io_perm_failure);
+
+ pci_lock_rescan_remove();
+ list_for_each_entry(hose, &hose_list, list_node) {
+ phb_pe = eeh_phb_pe_get(hose);
+ if (!phb_pe ||
+ !(phb_pe->state & EEH_PE_ISOLATED) ||
+ (phb_pe->state & EEH_PE_RECOVERING))
+ continue;
+
+ bus = eeh_pe_bus_get(phb_pe);
+ if (!bus) {
+ pr_err("%s: Cannot find PCI bus for "
+ "PHB#%x-PE#%x\n",
+ __func__,
+ pe->phb->global_number,
+ pe->addr);
+ break;
+ }
+ pci_hp_remove_devices(bus);
+ }
+ pci_unlock_rescan_remove();
+ }
+
+ /*
+ * If we have detected dead IOC, we needn't proceed
+ * any more since all PHBs would have been removed
+ */
+ if (rc == EEH_NEXT_ERR_DEAD_IOC)
+ break;
+ } while (rc != EEH_NEXT_ERR_NONE);
+}