linux/drivers/pci/pcie/err.c
Christoph Hellwig 5e69a33c5c PCI/ERR: Recognize disconnected devices in report_error_detected()
When a device is already unplugged by pciehp by the time the AER handler is
invoked, the PCIe device will already be in the pci_channel_io_perm_failure
state.  In that case simply return PCI_ERS_RESULT_DISCONNECT instead of
trying to do a state transition that will fail.

Also untangle the state transition failure from the lack of methods to
improve the debugging output in case it happens again.

Link: https://lore.kernel.org/r/20220601074024.3481035-1-hch@lst.de
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
2022-06-08 15:08:40 -05:00

265 lines
7.2 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* This file implements the error recovery as a core part of PCIe error
* reporting. When a PCIe error is delivered, an error message will be
* collected and printed to console, then, an error recovery procedure
* will be executed by following the PCI error recovery rules.
*
* Copyright (C) 2006 Intel Corp.
* Tom Long Nguyen (tom.l.nguyen@intel.com)
* Zhang Yanmin (yanmin.zhang@intel.com)
*/
#define dev_fmt(fmt) "AER: " fmt
#include <linux/pci.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/aer.h>
#include "portdrv.h"
#include "../pci.h"
static pci_ers_result_t merge_result(enum pci_ers_result orig,
enum pci_ers_result new)
{
if (new == PCI_ERS_RESULT_NO_AER_DRIVER)
return PCI_ERS_RESULT_NO_AER_DRIVER;
if (new == PCI_ERS_RESULT_NONE)
return orig;
switch (orig) {
case PCI_ERS_RESULT_CAN_RECOVER:
case PCI_ERS_RESULT_RECOVERED:
orig = new;
break;
case PCI_ERS_RESULT_DISCONNECT:
if (new == PCI_ERS_RESULT_NEED_RESET)
orig = PCI_ERS_RESULT_NEED_RESET;
break;
default:
break;
}
return orig;
}
static int report_error_detected(struct pci_dev *dev,
pci_channel_state_t state,
enum pci_ers_result *result)
{
struct pci_driver *pdrv;
pci_ers_result_t vote;
const struct pci_error_handlers *err_handler;
device_lock(&dev->dev);
pdrv = dev->driver;
if (pci_dev_is_disconnected(dev)) {
vote = PCI_ERS_RESULT_DISCONNECT;
} else if (!pci_dev_set_io_state(dev, state)) {
pci_info(dev, "can't recover (state transition %u -> %u invalid)\n",
dev->error_state, state);
vote = PCI_ERS_RESULT_NONE;
} else if (!pdrv || !pdrv->err_handler ||
!pdrv->err_handler->error_detected) {
/*
* If any device in the subtree does not have an error_detected
* callback, PCI_ERS_RESULT_NO_AER_DRIVER prevents subsequent
* error callbacks of "any" device in the subtree, and will
* exit in the disconnected error state.
*/
if (dev->hdr_type != PCI_HEADER_TYPE_BRIDGE) {
vote = PCI_ERS_RESULT_NO_AER_DRIVER;
pci_info(dev, "can't recover (no error_detected callback)\n");
} else {
vote = PCI_ERS_RESULT_NONE;
}
} else {
err_handler = pdrv->err_handler;
vote = err_handler->error_detected(dev, state);
}
pci_uevent_ers(dev, vote);
*result = merge_result(*result, vote);
device_unlock(&dev->dev);
return 0;
}
static int report_frozen_detected(struct pci_dev *dev, void *data)
{
return report_error_detected(dev, pci_channel_io_frozen, data);
}
static int report_normal_detected(struct pci_dev *dev, void *data)
{
return report_error_detected(dev, pci_channel_io_normal, data);
}
static int report_mmio_enabled(struct pci_dev *dev, void *data)
{
struct pci_driver *pdrv;
pci_ers_result_t vote, *result = data;
const struct pci_error_handlers *err_handler;
device_lock(&dev->dev);
pdrv = dev->driver;
if (!pdrv ||
!pdrv->err_handler ||
!pdrv->err_handler->mmio_enabled)
goto out;
err_handler = pdrv->err_handler;
vote = err_handler->mmio_enabled(dev);
*result = merge_result(*result, vote);
out:
device_unlock(&dev->dev);
return 0;
}
static int report_slot_reset(struct pci_dev *dev, void *data)
{
struct pci_driver *pdrv;
pci_ers_result_t vote, *result = data;
const struct pci_error_handlers *err_handler;
device_lock(&dev->dev);
pdrv = dev->driver;
if (!pdrv ||
!pdrv->err_handler ||
!pdrv->err_handler->slot_reset)
goto out;
err_handler = pdrv->err_handler;
vote = err_handler->slot_reset(dev);
*result = merge_result(*result, vote);
out:
device_unlock(&dev->dev);
return 0;
}
static int report_resume(struct pci_dev *dev, void *data)
{
struct pci_driver *pdrv;
const struct pci_error_handlers *err_handler;
device_lock(&dev->dev);
pdrv = dev->driver;
if (!pci_dev_set_io_state(dev, pci_channel_io_normal) ||
!pdrv ||
!pdrv->err_handler ||
!pdrv->err_handler->resume)
goto out;
err_handler = pdrv->err_handler;
err_handler->resume(dev);
out:
pci_uevent_ers(dev, PCI_ERS_RESULT_RECOVERED);
device_unlock(&dev->dev);
return 0;
}
/**
* pci_walk_bridge - walk bridges potentially AER affected
* @bridge: bridge which may be a Port, an RCEC, or an RCiEP
* @cb: callback to be called for each device found
* @userdata: arbitrary pointer to be passed to callback
*
* If the device provided is a bridge, walk the subordinate bus, including
* any bridged devices on buses under this bus. Call the provided callback
* on each device found.
*
* If the device provided has no subordinate bus, e.g., an RCEC or RCiEP,
* call the callback on the device itself.
*/
static void pci_walk_bridge(struct pci_dev *bridge,
int (*cb)(struct pci_dev *, void *),
void *userdata)
{
if (bridge->subordinate)
pci_walk_bus(bridge->subordinate, cb, userdata);
else
cb(bridge, userdata);
}
pci_ers_result_t pcie_do_recovery(struct pci_dev *dev,
pci_channel_state_t state,
pci_ers_result_t (*reset_subordinates)(struct pci_dev *pdev))
{
int type = pci_pcie_type(dev);
struct pci_dev *bridge;
pci_ers_result_t status = PCI_ERS_RESULT_CAN_RECOVER;
struct pci_host_bridge *host = pci_find_host_bridge(dev->bus);
/*
* If the error was detected by a Root Port, Downstream Port, RCEC,
* or RCiEP, recovery runs on the device itself. For Ports, that
* also includes any subordinate devices.
*
* If it was detected by another device (Endpoint, etc), recovery
* runs on the device and anything else under the same Port, i.e.,
* everything under "bridge".
*/
if (type == PCI_EXP_TYPE_ROOT_PORT ||
type == PCI_EXP_TYPE_DOWNSTREAM ||
type == PCI_EXP_TYPE_RC_EC ||
type == PCI_EXP_TYPE_RC_END)
bridge = dev;
else
bridge = pci_upstream_bridge(dev);
pci_dbg(bridge, "broadcast error_detected message\n");
if (state == pci_channel_io_frozen) {
pci_walk_bridge(bridge, report_frozen_detected, &status);
if (reset_subordinates(bridge) != PCI_ERS_RESULT_RECOVERED) {
pci_warn(bridge, "subordinate device reset failed\n");
goto failed;
}
} else {
pci_walk_bridge(bridge, report_normal_detected, &status);
}
if (status == PCI_ERS_RESULT_CAN_RECOVER) {
status = PCI_ERS_RESULT_RECOVERED;
pci_dbg(bridge, "broadcast mmio_enabled message\n");
pci_walk_bridge(bridge, report_mmio_enabled, &status);
}
if (status == PCI_ERS_RESULT_NEED_RESET) {
/*
* TODO: Should call platform-specific
* functions to reset slot before calling
* drivers' slot_reset callbacks?
*/
status = PCI_ERS_RESULT_RECOVERED;
pci_dbg(bridge, "broadcast slot_reset message\n");
pci_walk_bridge(bridge, report_slot_reset, &status);
}
if (status != PCI_ERS_RESULT_RECOVERED)
goto failed;
pci_dbg(bridge, "broadcast resume message\n");
pci_walk_bridge(bridge, report_resume, &status);
/*
* If we have native control of AER, clear error status in the device
* that detected the error. If the platform retained control of AER,
* it is responsible for clearing this status. In that case, the
* signaling device may not even be visible to the OS.
*/
if (host->native_aer || pcie_ports_native) {
pcie_clear_device_status(dev);
pci_aer_clear_nonfatal_status(dev);
}
pci_info(bridge, "device recovery successful\n");
return status;
failed:
pci_uevent_ers(bridge, PCI_ERS_RESULT_DISCONNECT);
/* TODO: Should kernel panic here? */
pci_info(bridge, "device recovery failed\n");
return status;
}