RE: [PATCH v13 3/4] cxl/core: Add CXL EINJ debugfs files

Dan Williams
2024-02-21T17:48:47Z

Ben Cheatham wrote:
> Export CXL helper functions in the einj_cxl module for getting/injecting
> available CXL protocol error types to sysfs under kernel/debug/cxl.
>
> The kernel/debug/cxl/einj_types file will print the available CXL
> protocol errors in the same format as the available_error_types
> file provided by the einj_cxl module. The
> kernel/debug/cxl/$dport_dev/einj_inject is functionally the same as the
> error_type and error_inject files provided by the EINJ module, i.e.:
> writing an error type into $dport_dev/einj_inject will inject said error
> type into the CXL dport represented by $dport_dev.
>
> Signed-off-by: Ben Cheatham <Benjamin.Cheatham@amd.com>
> ---
> Documentation/ABI/testing/debugfs-cxl | 30 ++++++++++++++++++++
> drivers/cxl/Kconfig | 1 +
> drivers/cxl/core/port.c | 41 +++++++++++++++++++++++++++
> 3 files changed, 72 insertions(+)
>
> diff --git a/Documentation/ABI/testing/debugfs-cxl b/Documentation/ABI/testing/debugfs-cxl
> index fe61d372e3fa..4c0f62f881ca 100644
> --- a/Documentation/ABI/testing/debugfs-cxl
> +++ b/Documentation/ABI/testing/debugfs-cxl
> @@ -33,3 +33,33 @@ Description:
> device cannot clear poison from the address, -ENXIO is returned.
> The clear_poison attribute is only visible for devices
> supporting the capability.
> +
> +What: /sys/kernel/debug/cxl/einj_types
> +Date: January, 2024
> +KernelVersion: v6.9
> +Contact: linux-cxl@vger.kernel.org
> +Description:
> + (RO) Prints the CXL protocol error types made available by
> + the platform in the format "0x<error number> <error type>".
> + The possible error types are (as of ACPI v6.5):
> + 0x1000 CXL.cache Protocol Correctable
> + 0x2000 CXL.cache Protocol Uncorrectable non-fatal
> + 0x4000 CXL.cache Protocol Uncorrectable fatal
> + 0x8000 CXL.mem Protocol Correctable
> + 0x10000 CXL.mem Protocol Uncorrectable non-fatal
> + 0x20000 CXL.mem Protocol Uncorrectable fatal
> +
> + The <error number> can be written to einj_inject to inject
> + <error type> into a chosen dport.
> +
> +What: /sys/kernel/debug/cxl/$dport_dev/einj_inject
> +Date: January, 2024
> +KernelVersion: v6.9
> +Contact: linux-cxl@vger.kernel.org
> +Description:
> + (WO) Writing an integer to this file injects the corresponding
> + CXL protocol error into $dport_dev ($dport_dev will be a device
> + name from /sys/bus/pci/devices). The integer to type mapping for
> + injection can be found by reading from einj_types. If the dport
> + was enumerated in RCH mode, a CXL 1.1 error is injected, otherwise
> + a CXL 2.0 error is injected.
> diff --git a/drivers/cxl/Kconfig b/drivers/cxl/Kconfig
> index 67998dbd1d46..c86ae4c65c03 100644
> --- a/drivers/cxl/Kconfig
> +++ b/drivers/cxl/Kconfig
> @@ -2,6 +2,7 @@
> menuconfig CXL_BUS
> tristate "CXL (Compute Express Link) Devices Support"
> depends on PCI
> + depends on ACPI_APEI_EINJ_CXL || !ACPI_APEI_EINJ_CXL

This statement is always true "x || !x"

I mentioned in the other patch that ACPI_APEI_EINJ_CXL needs to have a
dependency on CXL_BUS.