Re: [RFC PATCH 8/9] PCI/AER: Export pci_aer_unmask_internal_errors()

[Jonathan Cameron <Jonathan.Cameron@Huawei.com>]

On Mon, 17 Jun 2024 15:04:10 -0500
Terry Bowman <terry.bowman@amd.com> wrote:

> AER correctable internal errors (CIE) and AER uncorrectable internal
> errors (UIE) are disabled through the AER mask register by default.[1]
> 
> CXL PCIe ports use the CIE/UIE to report RAS errors and as a result
> need CIE/UIE enabled.[2]
> 
> Change pci_aer_unmask_internal_errors() function to be exported for
> the CXL driver and other drivers to use.

I've perhaps forgotten the end conclusion, but I thought there was
a request to just try enabling this in general and mask it out only
for known broken devices?

Admittedly that's a more daring path, so maybe I hallucinated it!

> 
> [1] PCI6.0 - 7.8.4.3 Uncorrectable
> [2] CXL3.1 - 12.2.2 CXL Root Ports, Downstream Switch Ports, and Upstream
>              Switch Ports
> 
> Signed-off-by: Terry Bowman <terry.bowman@amd.com>
> Cc: Bjorn Helgaas <bhelgaas@google.com>
> Cc: linux-pci@vger.kernel.org
> ---
>  drivers/pci/pcie/aer.c | 3 ++-
>  include/linux/aer.h    | 6 ++++++
>  2 files changed, 8 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/pci/pcie/aer.c b/drivers/pci/pcie/aer.c
> index 4dc03cb9aff0..d7a1982f0c50 100644
> --- a/drivers/pci/pcie/aer.c
> +++ b/drivers/pci/pcie/aer.c
> @@ -951,7 +951,7 @@ static bool find_source_device(struct pci_dev *parent,
>   * Note: AER must be enabled and supported by the device which must be
>   * checked in advance, e.g. with pcie_aer_is_native().
>   */
> -static void pci_aer_unmask_internal_errors(struct pci_dev *dev)
> +void pci_aer_unmask_internal_errors(struct pci_dev *dev)
>  {
>  	int aer = dev->aer_cap;
>  	u32 mask;
> @@ -964,6 +964,7 @@ static void pci_aer_unmask_internal_errors(struct pci_dev *dev)
>  	mask &= ~PCI_ERR_COR_INTERNAL;
>  	pci_write_config_dword(dev, aer + PCI_ERR_COR_MASK, mask);
>  }
> +EXPORT_SYMBOL_GPL(pci_aer_unmask_internal_errors);
>  
>  static bool is_cxl_mem_dev(struct pci_dev *dev)
>  {
> diff --git a/include/linux/aer.h b/include/linux/aer.h
> index 4b97f38f3fcf..a4fd25ea0280 100644
> --- a/include/linux/aer.h
> +++ b/include/linux/aer.h
> @@ -50,6 +50,12 @@ static inline int pci_aer_clear_nonfatal_status(struct pci_dev *dev)
>  static inline int pcie_aer_is_native(struct pci_dev *dev) { return 0; }
>  #endif
>  
> +#ifdef CONFIG_PCIEAER_CXL
> +void pci_aer_unmask_internal_errors(struct pci_dev *dev);
> +#else
> +static inline void pci_aer_unmask_internal_errors(struct pci_dev *dev) { }
> +#endif
> +
>  void pci_print_aer(struct pci_dev *dev, int aer_severity,
>  		    struct aer_capability_regs *aer);
>  int cper_severity_to_aer(int cper_severity);