On Tue, Nov 29, 2022 at 10:49:05AM -0700, Dave Jiang wrote:
> Some new devices such as CXL devices may want to record additional error
> information on a corrected error. Add a callback to allow the PCI device
> driver to do additional logging such as providing additional stats for user
> space RAS monitoring.
>
> For CXL device, this is actually a need due to CXL needing to write to the
> device AER status register in order to clear the unmasked CEs.
s/CE/correctable error/ since it's the first use and not common in
PCI-land.
"device AER status register" sounds like the PCIe AER Correctable
Error Status Register (PCIe r6.0, sec 7.8.4.5), but I think you mean
something else, maybe a CXL-specific register?
The PCIe core needs to own the AER one (PCI_ERR_COR_STATUS) so it can
coordinate ownership between firmware and Linux.
> Cc: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
> Suggested-by: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx>
> Reviewed-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@xxxxxxxxxxxxxxx>
> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx>
> Signed-off-by: Dave Jiang <dave.jiang@xxxxxxxxx>
Acked-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
> ---
> Documentation/PCI/pci-error-recovery.rst | 7 +++++++
> drivers/pci/pcie/aer.c | 8 +++++++-
> include/linux/pci.h | 3 +++
> 3 files changed, 17 insertions(+), 1 deletion(-)
>
> diff --git a/Documentation/PCI/pci-error-recovery.rst b/Documentation/PCI/pci-error-recovery.rst
> index 187f43a03200..690220255d5e 100644
> --- a/Documentation/PCI/pci-error-recovery.rst
> +++ b/Documentation/PCI/pci-error-recovery.rst
> @@ -83,6 +83,7 @@ This structure has the form::
> int (*mmio_enabled)(struct pci_dev *dev);
> int (*slot_reset)(struct pci_dev *dev);
> void (*resume)(struct pci_dev *dev);
> + void (*cor_error_log)(struct pci_dev *dev);
I think I would remove "log" from the name because it suggests this
hook should *only* log, and you need to actually clear some status.
Maybe "cor_error_detected()" to be analogous to error_detected()?
> };
>
> The possible channel states are::
> @@ -422,5 +423,11 @@ That is, the recovery API only requires that:
> - drivers/net/cxgb3
> - drivers/net/s2io.c
>
> + The cor_error_log() callback is invoked in handle_error_source() when
> + the error severity is "correctable". The callback is optional and allows
> + additional logging to be done if desired. See example:
> +
> + - drivers/cxl/pci.c
> +
> The End
> -------
> diff --git a/drivers/pci/pcie/aer.c b/drivers/pci/pcie/aer.c
> index e2d8a74f83c3..af1b5eecbb11 100644
> --- a/drivers/pci/pcie/aer.c
> +++ b/drivers/pci/pcie/aer.c
> @@ -961,8 +961,14 @@ 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);
> - if (pcie_aer_is_native(dev))
> + if (pcie_aer_is_native(dev)) {
> + struct pci_driver *pdrv = dev->driver;
> +
> + if (pdrv && pdrv->err_handler &&
> + pdrv->err_handler->cor_error_log)
> + pdrv->err_handler->cor_error_log(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/include/linux/pci.h b/include/linux/pci.h
> index 575849a100a3..54939b3426a9 100644
> --- a/include/linux/pci.h
> +++ b/include/linux/pci.h
> @@ -844,6 +844,9 @@ struct pci_error_handlers {
>
> /* Device driver may resume normal operations */
> void (*resume)(struct pci_dev *dev);
> +
> + /* Allow device driver to record more details of a correctable error */
> + void (*cor_error_log)(struct pci_dev *dev);
> };
>
>
>
>
