[PATCH 5.18 630/879] PCI/AER: Clear MULTI_ERR_COR/UNCOR_RCV bits

Greg Kroah-Hartman
2022-06-08T01:53:56Z

From: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>

[ 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: e167bfcaa4cd ("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>
---
drivers/pci/pcie/aer.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/pci/pcie/aer.c b/drivers/pci/pcie/aer.c
index 9fa1f97e5b27..7952e5efd6cf 100644
--- a/drivers/pci/pcie/aer.c
+++ b/drivers/pci/pcie/aer.c
@@ -101,6 +101,11 @@ struct aer_stats {
#define ERR_COR_ID(d) (d & 0xffff)
#define ERR_UNCOR_ID(d) (d >> 16)

+#define AER_ERR_STATUS_MASK (PCI_ERR_ROOT_UNCOR_RCV | \
+ PCI_ERR_ROOT_COR_RCV | \
+ PCI_ERR_ROOT_MULTI_COR_RCV | \
+ PCI_ERR_ROOT_MULTI_UNCOR_RCV)
+
static int pcie_aer_disable;
static pci_ers_result_t aer_root_reset(struct pci_dev *dev);

@@ -1196,7 +1201,7 @@ static irqreturn_t aer_irq(int irq, void *context)
struct aer_err_source e_src = {};

pci_read_config_dword(rp, aer + PCI_ERR_ROOT_STATUS, &e_src.status);
- if (!(e_src.status & (PCI_ERR_ROOT_UNCOR_RCV|PCI_ERR_ROOT_COR_RCV)))
+ if (!(e_src.status & AER_ERR_STATUS_MASK))
return IRQ_NONE;

pci_read_config_dword(rp, aer + PCI_ERR_ROOT_ERR_SRC, &e_src.id);
--
2.35.1