[PATCH v16 3/9] PCI/AER: Handle ERR_FATAL with removal and re-enumeration of devices

Oza Pawandeep
2018-05-11T10:43:22Z

This patch alters the behavior of handling of ERR_FATAL, where removal
of devices is initiated, followed by reset link, followed by
re-enumeration.

So the errors are handled in a different way as follows:
ERR_NONFATAL => call driver recovery entry points
ERR_FATAL => remove and re-enumerate

please refer to Documentation/PCI/pci-error-recovery.txt for more details.

Signed-off-by: Oza Pawandeep <poza@codeaurora.org>
Reviewed-by: Keith Busch <keith.busch@intel.com>

diff --git a/drivers/pci/pcie/aer/aerdrv_core.c b/drivers/pci/pcie/aer/aerdrv_core.c
index 0ea5acc..649dd1f 100644
--- a/drivers/pci/pcie/aer/aerdrv_core.c
+++ b/drivers/pci/pcie/aer/aerdrv_core.c
@@ -20,6 +20,7 @@
#include <linux/slab.h>
#include <linux/kfifo.h>
#include "aerdrv.h"
+#include "../../pci.h"

#define PCI_EXP_AER_FLAGS (PCI_EXP_DEVCTL_CERE | PCI_EXP_DEVCTL_NFERE | \
PCI_EXP_DEVCTL_FERE | PCI_EXP_DEVCTL_URRE)
@@ -475,35 +476,84 @@ static pci_ers_result_t reset_link(struct pci_dev *dev)
}

/**
- * do_recovery - handle nonfatal/fatal error recovery process
+ * do_fatal_recovery - handle fatal error recovery process
+ * @dev: pointer to a pci_dev data structure of agent detecting an error
+ *
+ * Invoked when an error is fatal. Once being invoked, removes the devices
+ * benetah this AER agent, followed by reset link e.g. secondary bus reset
+ * followed by re-enumeration of devices.
+ */
+
+static void do_fatal_recovery(struct pci_dev *dev)
+{
+ struct pci_dev *udev;
+ struct pci_bus *parent;
+ struct pci_dev *pdev, *temp;
+ pci_ers_result_t result = PCI_ERS_RESULT_RECOVERED;
+ struct aer_broadcast_data result_data;
+
+ if (dev->hdr_type == PCI_HEADER_TYPE_BRIDGE)
+ udev = dev;
+ else
+ udev = dev->bus->self;
+
+ parent = udev->subordinate;
+ pci_lock_rescan_remove();
+ list_for_each_entry_safe_reverse(pdev, temp, &parent->devices,
+ bus_list) {
+ pci_dev_get(pdev);
+ pci_dev_set_disconnected(pdev, NULL);
+ if (pci_has_subordinate(pdev))
+ pci_walk_bus(pdev->subordinate,
+ pci_dev_set_disconnected, NULL);
+ pci_stop_and_remove_bus_device(pdev);
+ pci_dev_put(pdev);
+ }
+
+ result = reset_link(udev);
+
+ if (dev->hdr_type == PCI_HEADER_TYPE_BRIDGE) {
+ /*
+ * If the error is reported by a bridge, we think this error
+ * is related to the downstream link of the bridge, so we
+ * do error recovery on all subordinates of the bridge instead
+ * of the bridge and clear the error status of the bridge.
+ */
+ pci_walk_bus(dev->subordinate, report_resume, &result_data);
+ pci_cleanup_aer_uncorrect_error_status(dev);
+ }
+
+ if (result == PCI_ERS_RESULT_RECOVERED) {
+ if (pcie_wait_for_link(udev, true))
+ pci_rescan_bus(udev->bus);
+ } else {
+ pci_uevent_ers(dev, PCI_ERS_RESULT_DISCONNECT);
+ pci_info(dev, "AER: Device recovery failed\n");
+ }
+
+ pci_unlock_rescan_remove();
+}
+
+/**
+ * do_nonfatal_recovery - handle nonfatal error recovery process
* @dev: pointer to a pci_dev data structure of agent detecting an error
- * @severity: error severity type
*
* Invoked when an error is nonfatal/fatal. Once being invoked, broadcast
* error detected message to all downstream drivers within a hierarchy in
* question and return the returned code.
*/
-static void do_recovery(struct pci_dev *dev, int severity)
+static void do_nonfatal_recovery(struct pci_dev *dev)
{
- pci_ers_result_t status, result = PCI_ERS_RESULT_RECOVERED;
+ pci_ers_result_t status;
enum pci_channel_state state;

- if (severity == AER_FATAL)
- state = pci_channel_io_frozen;
- else
- state = pci_channel_io_normal;
+ state = pci_channel_io_normal;

status = broadcast_error_message(dev,
state,
"error_detected",
report_error_detected);

- if (severity == AER_FATAL) {
- result = reset_link(dev);
- if (result != PCI_ERS_RESULT_RECOVERED)
- goto failed;
- }
-
if (status == PCI_ERS_RESULT_CAN_RECOVER)
status = broadcast_error_message(dev,
state,
@@ -562,8 +612,10 @@ static void handle_error_source(struct pcie_device *aerdev,
if (pos)
pci_write_config_dword(dev, pos + PCI_ERR_COR_STATUS,
info->status);
- } else
- do_recovery(dev, info->severity);
+ } else if (info->severity == AER_NONFATAL)
+ do_nonfatal_recovery(dev);
+ else if (info->severity == AER_FATAL)
+ do_fatal_recovery(dev);
}

#ifdef CONFIG_ACPI_APEI_PCIEAER
@@ -627,8 +679,10 @@ static void aer_recover_work_func(struct work_struct *work)
continue;
}
cper_print_aer(pdev, entry.severity, entry.regs);
- if (entry.severity != AER_CORRECTABLE)
- do_recovery(pdev, entry.severity);
+ if (entry.severity == AER_NONFATAL)
+ do_nonfatal_recovery(pdev);
+ else if (entry.severity == AER_FATAL)
+ do_fatal_recovery(pdev);
pci_dev_put(pdev);
}
}
--
2.7.4