kernel_optimize_test/drivers/pci/pcie
Kuppuswamy Sathyanarayanan 40d428b528 PCI/AER: Clear MULTI_ERR_COR/UNCOR_RCV bits
[ Upstream commit 203926da2bff8e172200a2f11c758987af112d4a ]

When a Root Port or Root Complex Event Collector receives an error Message
e.g., ERR_COR, it sets PCI_ERR_ROOT_COR_RCV in the Root Error Status
register and logs the Requester ID in the Error Source Identification
register.  If it receives a second ERR_COR Message before software clears
PCI_ERR_ROOT_COR_RCV, hardware sets PCI_ERR_ROOT_MULTI_COR_RCV and the
Requester ID is lost.

In the following scenario, PCI_ERR_ROOT_MULTI_COR_RCV was never cleared:

  - hardware receives ERR_COR message
  - hardware sets PCI_ERR_ROOT_COR_RCV
  - aer_irq() entered
  - aer_irq(): status = pci_read_config_dword(PCI_ERR_ROOT_STATUS)
  - aer_irq(): now status == PCI_ERR_ROOT_COR_RCV
  - hardware receives second ERR_COR message
  - hardware sets PCI_ERR_ROOT_MULTI_COR_RCV
  - aer_irq(): pci_write_config_dword(PCI_ERR_ROOT_STATUS, status)
  - PCI_ERR_ROOT_COR_RCV is cleared; PCI_ERR_ROOT_MULTI_COR_RCV is set
  - aer_irq() entered again
  - aer_irq(): status = pci_read_config_dword(PCI_ERR_ROOT_STATUS)
  - aer_irq(): now status == PCI_ERR_ROOT_MULTI_COR_RCV
  - aer_irq() exits because PCI_ERR_ROOT_COR_RCV not set
  - PCI_ERR_ROOT_MULTI_COR_RCV is still set

The same problem occurred with ERR_NONFATAL/ERR_FATAL Messages and
PCI_ERR_ROOT_UNCOR_RCV and PCI_ERR_ROOT_MULTI_UNCOR_RCV.

Fix the problem by queueing an AER event and clearing the Root Error Status
bits when any of these bits are set:

  PCI_ERR_ROOT_COR_RCV
  PCI_ERR_ROOT_UNCOR_RCV
  PCI_ERR_ROOT_MULTI_COR_RCV
  PCI_ERR_ROOT_MULTI_UNCOR_RCV

See the bugzilla link for details from Eric about how to reproduce this
problem.

[bhelgaas: commit log, move repro details to bugzilla]
Fixes: e167bfcaa4 ("PCI: aerdrv: remove magical ROOT_ERR_STATUS_MASKS")
Link: https://bugzilla.kernel.org/show_bug.cgi?id=215992
Link: https://lore.kernel.org/r/20220418150237.1021519-1-sathyanarayanan.kuppuswamy@linux.intel.com
Reported-by: Eric Badger <ebadger@purestorage.com>
Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Ashok Raj <ashok.raj@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-06-09 10:21:17 +02:00
..
aer_inject.c
aer.c PCI/AER: Clear MULTI_ERR_COR/UNCOR_RCV bits 2022-06-09 10:21:17 +02:00
aspm.c
dpc.c PCI: pciehp: Ignore Link Down/Up caused by DPC 2021-07-20 16:05:47 +02:00
edr.c
err.c
Kconfig
Makefile
pme.c
portdrv_core.c PCI/portdrv: Enable Bandwidth Notification only if port supports it 2021-09-18 13:40:10 +02:00
portdrv_pci.c
portdrv.h
ptm.c