Re: [PATCH 6/7] PCI/AER: Renumber severity constants

[Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>]

Hi Lukas,

On 9/27/2026 11:02 AM, Lukas Wunner wrote:
> The AER driver uses constants for Correctable, Non-Fatal and Fatal Error
> severity which look as if they match something in the spec, but are
> actually just made-up numbers.
> 
> Use the bit number in the Device Status Register instead (PCIe r7.1 sec
> 7.5.3.5).  A subsequent commit takes advantage of this by using BIT() to
> conveniently compute the register bit corresponding to a given severity.
> 
> While at it, drop the DPC_FATAL constant which was introduced by commit
> b09803b5e546 ("PCI/DPC: Use the generic pcie_do_fatal_recovery() path")
> but never saw any use in 8 years.
> 

This changes the raw severity value in the aer_event tracepoint, which
may break userspace.  rasdaemon relies on the current numbering
(enum hw_event_aer_err_type in core/ras-events.h), so it would
misclassify error.


> Signed-off-by: Lukas Wunner <lukas@wunner.de>
> ---
>  drivers/pci/pcie/aer.c  | 2 +-
>  include/linux/aer.h     | 8 ++++----
>  include/ras/ras_event.h | 2 +-
>  3 files changed, 6 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/pci/pcie/aer.c b/drivers/pci/pcie/aer.c
> index 34a8eddc427a..6bc843ab9b37 100644
> --- a/drivers/pci/pcie/aer.c
> +++ b/drivers/pci/pcie/aer.c
> @@ -504,9 +504,9 @@ void pci_aer_exit(struct pci_dev *dev)
>   * AER error strings
>   */
>  static const char * const aer_error_severity_string[] = {
> +	"Correctable",
>  	"Uncorrectable (Non-Fatal)",
>  	"Uncorrectable (Fatal)",
> -	"Correctable"
>  };
>  
>  static const char *aer_error_layer[] = {
> diff --git a/include/linux/aer.h b/include/linux/aer.h
> index df0f5c382286..795c55132008 100644
> --- a/include/linux/aer.h
> +++ b/include/linux/aer.h
> @@ -11,10 +11,10 @@
>  #include <linux/errno.h>
>  #include <linux/types.h>
>  
> -#define AER_NONFATAL			0
> -#define AER_FATAL			1
> -#define AER_CORRECTABLE			2
> -#define DPC_FATAL			3
> +/* Must match bit number in Device Status Register (PCIe r7.1, sec 7.5.3.5) */
> +#define AER_CORRECTABLE			0
> +#define AER_NONFATAL			1
> +#define AER_FATAL			2
>  
>  /*
>   * AER and DPC capabilities TLP Logging register sizes (PCIe r6.2, sec 7.8.4
> diff --git a/include/ras/ras_event.h b/include/ras/ras_event.h
> index fdb785fa4613..1e03ade99386 100644
> --- a/include/ras/ras_event.h
> +++ b/include/ras/ras_event.h
> @@ -302,7 +302,7 @@ TRACE_EVENT(non_standard_event,
>   *			([domain:]bus:device.function).
>   * u32 status -		Either the correctable or uncorrectable register
>   *			indicating what error or errors have been seen
> - * u8 severity -	error severity 0:NONFATAL 1:FATAL 2:CORRECTED
> + * u8 severity -	error severity 0:CORRECTED 1:NONFATAL 2:FATAL
>   */
>  
>  #define aer_correctable_errors					\

-- 
Sathyanarayanan Kuppuswamy
Linux Kernel Developer