Re: [PATCH 6/6 v7] ACPI: extlog: Trace CPER CXL Protocol Error Section

[Dave Jiang <dave.jiang@intel.com>]

On 11/4/25 11:22 AM, Fabio M. De Francesco wrote:
> When Firmware First is enabled, BIOS handles errors first and then it
> makes them available to the kernel via the Common Platform Error Record
> (CPER) sections (UEFI 2.11 Appendix N.2.13). Linux parses the CPER
> sections via one of two similar paths, either ELOG or GHES. The errors
> managed by ELOG are signaled to the BIOS by the I/O Machine Check
> Architecture (I/O MCA).
> 
> Currently, ELOG and GHES show some inconsistencies in how they report to
> userspace via trace events.
> 
> Therefore, make the two mentioned paths act similarly by tracing the CPER
> CXL Protocol Error Section.
> 
> Cc: Dan Williams <dan.j.williams@intel.com>
> Reviewed-by: Jonathan Cameron <jonathan.cameron@huawei.com>
> Reviewed-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
> Signed-off-by: Fabio M. De Francesco <fabio.m.de.francesco@linux.intel.com>

Reviewed-by: Dave Jiang <dave.jiang@intel.com>> ---
>  drivers/acpi/Kconfig       |  1 +
>  drivers/acpi/acpi_extlog.c | 22 ++++++++++++++++++++++
>  drivers/cxl/core/ras.c     |  3 ++-
>  include/cxl/event.h        |  2 ++
>  4 files changed, 27 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/acpi/Kconfig b/drivers/acpi/Kconfig
> index be02634f2320..c2ad24e77ddf 100644
> --- a/drivers/acpi/Kconfig
> +++ b/drivers/acpi/Kconfig
> @@ -498,6 +498,7 @@ config ACPI_EXTLOG
>  	select ACPI_APEI
>  	select ACPI_APEI_PCIEAER
>  	select UEFI_CPER
> +	select CXL_BUS
>  	help
>  	  Certain usages such as Predictive Failure Analysis (PFA) require
>  	  more information about the error than what can be described in
> diff --git a/drivers/acpi/acpi_extlog.c b/drivers/acpi/acpi_extlog.c
> index b3976ceb4ee4..e6fb25395984 100644
> --- a/drivers/acpi/acpi_extlog.c
> +++ b/drivers/acpi/acpi_extlog.c
> @@ -12,6 +12,7 @@
>  #include <linux/ratelimit.h>
>  #include <linux/edac.h>
>  #include <linux/ras.h>
> +#include <cxl/event.h>
>  #include <acpi/ghes.h>
>  #include <asm/cpu.h>
>  #include <asm/mce.h>
> @@ -160,6 +161,21 @@ static void extlog_print_pcie(struct cper_sec_pcie *pcie_err,
>  	pci_dev_put(pdev);
>  }
>  
> +static void
> +extlog_cxl_cper_handle_prot_err(struct cxl_cper_sec_prot_err *prot_err,
> +				int severity)
> +{
> +	struct cxl_cper_prot_err_work_data wd;
> +
> +	if (cxl_cper_sec_prot_err_valid(prot_err))
> +		return;
> +
> +	if (cxl_cper_setup_prot_err_work_data(&wd, prot_err, severity))
> +		return;
> +
> +	cxl_cper_handle_prot_err(&wd);
> +}
> +
>  static int extlog_print(struct notifier_block *nb, unsigned long val,
>  			void *data)
>  {
> @@ -211,6 +227,12 @@ static int extlog_print(struct notifier_block *nb, unsigned long val,
>  			if (gdata->error_data_length >= sizeof(*mem))
>  				trace_extlog_mem_event(mem, err_seq, fru_id, fru_text,
>  						       (u8)gdata->error_severity);
> +		} else if (guid_equal(sec_type, &CPER_SEC_CXL_PROT_ERR)) {
> +			struct cxl_cper_sec_prot_err *prot_err =
> +				acpi_hest_get_payload(gdata);
> +
> +			extlog_cxl_cper_handle_prot_err(prot_err,
> +							gdata->error_severity);
>  		} else if (guid_equal(sec_type, &CPER_SEC_PCIE)) {
>  			struct cper_sec_pcie *pcie_err = acpi_hest_get_payload(gdata);
>  
> diff --git a/drivers/cxl/core/ras.c b/drivers/cxl/core/ras.c
> index 2731ba3a0799..a90480d07c87 100644
> --- a/drivers/cxl/core/ras.c
> +++ b/drivers/cxl/core/ras.c
> @@ -63,7 +63,7 @@ static int match_memdev_by_parent(struct device *dev, const void *uport)
>  	return 0;
>  }
>  
> -static void cxl_cper_handle_prot_err(struct cxl_cper_prot_err_work_data *data)
> +void cxl_cper_handle_prot_err(struct cxl_cper_prot_err_work_data *data)
>  {
>  	unsigned int devfn = PCI_DEVFN(data->prot_err.agent_addr.device,
>  				       data->prot_err.agent_addr.function);
> @@ -104,6 +104,7 @@ static void cxl_cper_handle_prot_err(struct cxl_cper_prot_err_work_data *data)
>  	else
>  		cxl_cper_trace_uncorr_prot_err(cxlmd, data->ras_cap);
>  }
> +EXPORT_SYMBOL_GPL(cxl_cper_handle_prot_err);
>  
>  static void cxl_cper_prot_err_work_fn(struct work_struct *work)
>  {
> diff --git a/include/cxl/event.h b/include/cxl/event.h
> index 94081aec597a..ff97fea718d2 100644
> --- a/include/cxl/event.h
> +++ b/include/cxl/event.h
> @@ -340,4 +340,6 @@ cxl_cper_setup_prot_err_work_data(struct cxl_cper_prot_err_work_data *wd,
>  }
>  #endif
>  
> +void cxl_cper_handle_prot_err(struct cxl_cper_prot_err_work_data *wd);
> +
>  #endif /* _LINUX_CXL_EVENT_H */