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authorJonathan Cameron <Jonathan.Cameron@huawei.com>2020-06-22 19:35:23 +0800
committerBjorn Helgaas <bhelgaas@google.com>2020-07-22 15:41:03 -0500
commit068c29a248b6ddbfdf7bb150b547569759620d36 (patch)
tree1533d2db55c0a1371985e1746d8fdb6acadedba9 /drivers
parent600a5b4fc8e8f6dad098cd50e0e727cb2a16be46 (diff)
downloadlwn-068c29a248b6ddbfdf7bb150b547569759620d36.tar.gz
lwn-068c29a248b6ddbfdf7bb150b547569759620d36.zip
PCI/ERR: Clear PCIe Device Status errors only if OS owns AER
pcie_clear_device_status() resets the error bits in the PCIe Device Status Register (PCI_EXP_DEVSTA). Previously we did this unconditionally, but on ACPI systems, the _OSC AER bit negotiates control of the AER capability. Per sec 4.5.1 of the System Firmware Intermediary _OSC and DPC Updates ECN [1], this bit also covers other error enable/status bits including the following: Correctable Error Reporting Enable Non-Fatal Error Reporting Enable Fatal Error Reporting Enable Unsupported Request Reporting Enable These bits are all in the PCIe Device Control register (the ECN omitted "Reporting", but I think that's a typo), so by implication the _OSC AER bit also applies to the error status bits in the PCIe Device Status register: Correctable Error Detected Non-Fatal Error Detected Fatal Error Detected Unsupported Request Detected Clear the PCIe Device Status error bits only when the OS controls the AER capability and related error enable/status bits. If platform firmware controls the AER capability, firmware is responsible for clearing these bits. One call path leading here is: ghes_do_proc ghes_handle_aer aer_recover_queue schedule_work(&aer_recover_work) ... aer_recover_work_func pcie_do_recovery pcie_clear_device_status [1] System Firmware Intermediary (SFI) _OSC and DPC Updates ECN, Feb 24, 2020, affecting PCI Firmware Specification, Rev. 3.2 https://members.pcisig.com/wg/PCI-SIG/document/14076 [bhelgaas: commit log, move test from pcie_clear_device_status() to callers] Link: https://lore.kernel.org/r/20200622113523.891666-1-Jonathan.Cameron@huawei.com Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/pci/pcie/aer.c3
-rw-r--r--drivers/pci/pcie/err.c3
2 files changed, 4 insertions, 2 deletions
diff --git a/drivers/pci/pcie/aer.c b/drivers/pci/pcie/aer.c
index f6d778308558..cccd6747e5f6 100644
--- a/drivers/pci/pcie/aer.c
+++ b/drivers/pci/pcie/aer.c
@@ -939,7 +939,8 @@ static void handle_error_source(struct pci_dev *dev, struct aer_err_info *info)
if (aer)
pci_write_config_dword(dev, aer + PCI_ERR_COR_STATUS,
info->status);
- pcie_clear_device_status(dev);
+ if (pcie_aer_is_native(dev))
+ pcie_clear_device_status(dev);
} else if (info->severity == AER_NONFATAL)
pcie_do_recovery(dev, pci_channel_io_normal, aer_root_reset);
else if (info->severity == AER_FATAL)
diff --git a/drivers/pci/pcie/err.c b/drivers/pci/pcie/err.c
index 55755bc493f1..c543f419d8f9 100644
--- a/drivers/pci/pcie/err.c
+++ b/drivers/pci/pcie/err.c
@@ -197,7 +197,8 @@ pci_ers_result_t pcie_do_recovery(struct pci_dev *dev,
pci_dbg(dev, "broadcast resume message\n");
pci_walk_bus(bus, report_resume, &status);
- pcie_clear_device_status(dev);
+ if (pcie_aer_is_native(dev))
+ pcie_clear_device_status(dev);
pci_aer_clear_nonfatal_status(dev);
pci_info(dev, "device recovery successful\n");
return status;