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PCI/ERR: Handle fatal error recovery 

We don't need to be paranoid about the topology changing while handling an
error.  If the device has changed in a hotplug capable slot, we can rely on
the presence detection handling to react to a changing topology.

Restore the fatal error handling behavior that existed before merging DPC
with AER with 7e9084b367 ("PCI/AER: Handle ERR_FATAL with removal and
re-enumeration of devices").

Signed-off-by: Keith Busch <keith.busch@intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Sinan Kaya <okaya@kernel.org>
hifive-unleashed-5.1
Keith Busch 2018-09-20 10:27:12 -06:00 committed by Bjorn Helgaas
parent c4eed62a21
commit bdb5ac8577
5 changed files with 28 additions and 102 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

35
Documentation/PCI/pci-error-recovery.txt
View File

@ -110,7 +110,7 @@ The actual steps taken by a platform to recover from a PCI error
event will be platform-dependent, but will follow the general
sequence described below.
STEP 0: Error Event: ERR_NONFATAL
STEP 0: Error Event
-------------------
A PCI bus error is detected by the PCI hardware. On powerpc, the slot
is isolated, in that all I/O is blocked: all reads return 0xffffffff,
@ -228,7 +228,13 @@ proceeds to either STEP3 (Link Reset) or to STEP 5 (Resume Operations).
If any driver returned PCI_ERS_RESULT_NEED_RESET, then the platform
proceeds to STEP 4 (Slot Reset)
STEP 3: Slot Reset
STEP 3: Link Reset
------------------
The platform resets the link. This is a PCI-Express specific step
and is done whenever a fatal error has been detected that can be
"solved" by resetting the link.
STEP 4: Slot Reset
------------------
In response to a return value of PCI_ERS_RESULT_NEED_RESET, the
@ -314,7 +320,7 @@ Failure).
>>> However, it probably should.
STEP 4: Resume Operations
STEP 5: Resume Operations
-------------------------
The platform will call the resume() callback on all affected device
drivers if all drivers on the segment have returned
@ -326,7 +332,7 @@ a result code.
At this point, if a new error happens, the platform will restart
a new error recovery sequence.
STEP 5: Permanent Failure
STEP 6: Permanent Failure
-------------------------
A "permanent failure" has occurred, and the platform cannot recover
the device. The platform will call error_detected() with a
@ -349,27 +355,6 @@ errors. See the discussion in powerpc/eeh-pci-error-recovery.txt
for additional detail on real-life experience of the causes of
software errors.
STEP 0: Error Event: ERR_FATAL
-------------------
PCI bus error is detected by the PCI hardware. On powerpc, the slot is
isolated, in that all I/O is blocked: all reads return 0xffffffff, all
writes are ignored.
STEP 1: Remove devices
--------------------
Platform removes the devices depending on the error agent, it could be
this port for all subordinates or upstream component (likely downstream
port)
STEP 2: Reset link
--------------------
The platform resets the link. This is a PCI-Express specific step and is
done whenever a fatal error has been detected that can be "solved" by
resetting the link.
STEP 3: Re-enumerate the devices
--------------------
Initiates the re-enumeration.
Conclusion; General Remarks
---------------------------

4
drivers/pci/pci.h
View File

@ -433,8 +433,8 @@ static inline int pci_dev_specific_disable_acs_redir(struct pci_dev *dev)
#endif
/* PCI error reporting and recovery */
void pcie_do_fatal_recovery(struct pci_dev *dev, u32 service);
void pcie_do_nonfatal_recovery(struct pci_dev *dev);
void pcie_do_recovery(struct pci_dev *dev, enum pci_channel_state state,
u32 service);
bool pcie_wait_for_link(struct pci_dev *pdev, bool active);
#ifdef CONFIG_PCIEASPM

12
drivers/pci/pcie/aer.c
View File

@ -1010,9 +1010,11 @@ static void handle_error_source(struct pci_dev *dev, struct aer_err_info *info)
info->status);
pci_aer_clear_device_status(dev);
} else if (info->severity == AER_NONFATAL)
pcie_do_nonfatal_recovery(dev);
pcie_do_recovery(dev, pci_channel_io_normal,
PCIE_PORT_SERVICE_AER);
else if (info->severity == AER_FATAL)
pcie_do_fatal_recovery(dev, PCIE_PORT_SERVICE_AER);
pcie_do_recovery(dev, pci_channel_io_frozen,
PCIE_PORT_SERVICE_AER);
pci_dev_put(dev);
}
@ -1048,9 +1050,11 @@ static void aer_recover_work_func(struct work_struct *work)
}
cper_print_aer(pdev, entry.severity, entry.regs);
if (entry.severity == AER_NONFATAL)
pcie_do_nonfatal_recovery(pdev);
pcie_do_recovery(pdev, pci_channel_io_normal,
PCIE_PORT_SERVICE_AER);
else if (entry.severity == AER_FATAL)
pcie_do_fatal_recovery(pdev, PCIE_PORT_SERVICE_AER);
pcie_do_recovery(pdev, pci_channel_io_frozen,
PCIE_PORT_SERVICE_AER);
pci_dev_put(pdev);
}
}

4
drivers/pci/pcie/dpc.c
View File

@ -216,7 +216,7 @@ static irqreturn_t dpc_handler(int irq, void *context)
reason = (status & PCI_EXP_DPC_STATUS_TRIGGER_RSN) >> 1;
ext_reason = (status & PCI_EXP_DPC_STATUS_TRIGGER_RSN_EXT) >> 5;
dev_warn(dev, "DPC %s detected, remove downstream devices\n",
dev_warn(dev, "DPC %s detected\n",
(reason == 0) ? "unmasked uncorrectable error" :
(reason == 1) ? "ERR_NONFATAL" :
(reason == 2) ? "ERR_FATAL" :
@ -233,7 +233,7 @@ static irqreturn_t dpc_handler(int irq, void *context)
}
/* We configure DPC so it only triggers on ERR_FATAL */
pcie_do_fatal_recovery(pdev, PCIE_PORT_SERVICE_DPC);
pcie_do_recovery(pdev, pci_channel_io_frozen, PCIE_PORT_SERVICE_DPC);
return IRQ_HANDLED;
}

75
drivers/pci/pcie/err.c
View File

@ -271,83 +271,20 @@ static pci_ers_result_t broadcast_error_message(struct pci_dev *dev,
return result_data.result;
}
/**
* pcie_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
* beneath this AER agent, followed by reset link e.g. secondary bus reset
* followed by re-enumeration of devices.
*/
void pcie_do_fatal_recovery(struct pci_dev *dev, u32 service)
{
struct pci_dev *udev;
struct pci_bus *parent;
struct pci_dev *pdev, *temp;
pci_ers_result_t result;
if (dev->hdr_type == PCI_HEADER_TYPE_BRIDGE)
udev = dev;
else
udev = dev->bus->self;
parent = udev->subordinate;
pci_walk_bus(parent, pci_dev_set_disconnected, NULL);
pci_lock_rescan_remove();
pci_dev_get(dev);
list_for_each_entry_safe_reverse(pdev, temp, &parent->devices,
bus_list) {
pci_stop_and_remove_bus_device(pdev);
}
result = reset_link(udev, service);
if ((service == PCIE_PORT_SERVICE_AER) &&
(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_aer_clear_fatal_status(dev);
pci_aer_clear_device_status(dev);
}
if (result == PCI_ERS_RESULT_RECOVERED) {
if (pcie_wait_for_link(udev, true))
pci_rescan_bus(udev->bus);
pci_info(dev, "Device recovery from fatal error successful\n");
} else {
pci_uevent_ers(dev, PCI_ERS_RESULT_DISCONNECT);
pci_info(dev, "Device recovery from fatal error failed\n");
}
pci_dev_put(dev);
pci_unlock_rescan_remove();
}
/**
* pcie_do_nonfatal_recovery - handle nonfatal error recovery process
* @dev: pointer to a pci_dev data structure of agent detecting an error
*
* 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.
*/
void pcie_do_nonfatal_recovery(struct pci_dev *dev)
void pcie_do_recovery(struct pci_dev *dev, enum pci_channel_state state,
u32 service)
{
pci_ers_result_t status;
enum pci_channel_state state;
state = pci_channel_io_normal;
status = broadcast_error_message(dev,
state,
"error_detected",
report_error_detected);
if (state == pci_channel_io_frozen &&
reset_link(dev, service) != PCI_ERS_RESULT_RECOVERED)
goto failed;
if (status == PCI_ERS_RESULT_CAN_RECOVER)
status = broadcast_error_message(dev,
state,