On Thu, 26 Jun 2025 17:42:42 -0500
Terry Bowman <terry.bowman@xxxxxxx> wrote:
> Create cxl_do_recovery() to provide uncorrectable protocol error (UCE)
> handling. Follow similar design as found in PCIe error driver,
> pcie_do_recovery(). One difference is cxl_do_recovery() will treat all UCEs
> as fatal with a kernel panic. This is to prevent corruption on CXL memory.
>
> Export the PCI error driver's merge_result() to CXL namespace.
I think this may be a confusion from earlier review. Anyhow, it should
be namespaced in the sense of not exporting something the vague name of
merge_result but it's PCI code, not CXL code and we don't have the dangerous
interface argument to justify putting it in the CXL namespace so I think
a namespaced EXPORT makes little sense for this one.
Jonathan
> Introduce
> PCI_ERS_RESULT_PANIC and add support in merge_result() routine. This will
> be used by CXL to panic the system in the case of uncorrectable protocol
> errors. PCI error handling is not currently expected to use the
> PCI_ERS_RESULT_PANIC.
>
> Copy pci_walk_bridge() to cxl_walk_bridge(). Make a change to walk the
> first device in all cases.
>
> Copy the PCI error driver's report_error_detected() to cxl_report_error_detected().
> Note, only CXL Endpoints and RCH Downstream Ports(RCH DSP) are currently
> supported. Add locking for PCI device as done in PCI's report_error_detected().
> This is necessary to prevent the RAS registers from disappearing before
> logging is completed.
>
> Call panic() to halt the system in the case of uncorrectable errors (UCE)
> in cxl_do_recovery(). Export pci_aer_clear_fatal_status() for CXL to use
> if a UCE is not found. In this case the AER status must be cleared and
> uses pci_aer_clear_fatal_status().
>
> Signed-off-by: Terry Bowman <terry.bowman@xxxxxxx>
> diff --git a/drivers/pci/pcie/err.c b/drivers/pci/pcie/err.c
> index de6381c690f5..63fceb3e8613 100644
> --- a/drivers/pci/pcie/err.c
> +++ b/drivers/pci/pcie/err.c
> @@ -21,9 +21,12 @@
> #include "portdrv.h"
> #include "../pci.h"
>
> -static pci_ers_result_t merge_result(enum pci_ers_result orig,
> - enum pci_ers_result new)
> +pci_ers_result_t merge_result(enum pci_ers_result orig,
> + enum pci_ers_result new)
> {
> + if (new == PCI_ERS_RESULT_PANIC)
> + return PCI_ERS_RESULT_PANIC;
> +
> if (new == PCI_ERS_RESULT_NO_AER_DRIVER)
> return PCI_ERS_RESULT_NO_AER_DRIVER;
>
> @@ -45,6 +48,7 @@ static pci_ers_result_t merge_result(enum pci_ers_result orig,
>
> return orig;
> }
> +EXPORT_SYMBOL_NS_GPL(merge_result, "CXL");
Do we care about namespacing this? I think not given it is PCIe code
and hardly destructive for other drivers to mess with it if they like.
I would namespace it in the sense of renaming it to make it clear
it's about pci errors though.
pci_ers_merge_result() perhaps?
Do that as a percursor patch.
>
> static int report_error_detected(struct pci_dev *dev,
> pci_channel_state_t state,
