Ben Cheatham wrote:
> Implement CXL helper functions in the EINJ module for getting/injecting
> available CXL protocol error types and export them 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 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 $dport_dev.
>
> Signed-off-by: Ben Cheatham <Benjamin.Cheatham@xxxxxxx>
> ---
> Documentation/ABI/testing/debugfs-cxl | 22 ++++
> drivers/acpi/apei/einj.c | 144 ++++++++++++++++++++++++--
> drivers/cxl/core/port.c | 39 +++++++
> include/linux/einj-cxl.h | 42 ++++++++
> 4 files changed, 237 insertions(+), 10 deletions(-)
> create mode 100644 include/linux/einj-cxl.h
>
> diff --git a/Documentation/ABI/testing/debugfs-cxl b/Documentation/ABI/testing/debugfs-cxl
> index fe61d372e3fa..bcd985cca66a 100644
> --- a/Documentation/ABI/testing/debugfs-cxl
> +++ b/Documentation/ABI/testing/debugfs-cxl
> @@ -33,3 +33,25 @@ Description:
> device cannot clear poison from the address, -ENXIO is returned.
> The clear_poison attribute is only visible for devices
> supporting the capability.
> +
> +What: /sys/kernel/debug/cxl/einj_types
> +Date: January, 2024
> +KernelVersion: v6.9
> +Contact: linux-cxl@xxxxxxxxxxxxxxx
> +Description:
> + (RO) Prints the CXL protocol error types made available by
> + the platform in the format "0x<error number> <error type>".
> + The <error number> can be written to einj_inject to inject
> + <error type> into a chosen dport.
> +
> +What: /sys/kernel/debug/cxl/$dport_dev/einj_inject
> +Date: January, 2024
> +KernelVersion: v6.9
> +Contact: linux-cxl@xxxxxxxxxxxxxxx
> +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/acpi/apei/einj.c b/drivers/acpi/apei/einj.c
> index 10d51cd73fa4..c3ec03583946 100644
> --- a/drivers/acpi/apei/einj.c
> +++ b/drivers/acpi/apei/einj.c
> @@ -21,6 +21,7 @@
> #include <linux/nmi.h>
> #include <linux/delay.h>
> #include <linux/mm.h>
> +#include <linux/einj-cxl.h>
> #include <linux/platform_device.h>
> #include <asm/unaligned.h>
>
> @@ -37,6 +38,12 @@
> #define MEM_ERROR_MASK (ACPI_EINJ_MEMORY_CORRECTABLE | \
> ACPI_EINJ_MEMORY_UNCORRECTABLE | \
> ACPI_EINJ_MEMORY_FATAL)
> +#define CXL_ERROR_MASK (ACPI_EINJ_CXL_CACHE_CORRECTABLE | \
> + ACPI_EINJ_CXL_CACHE_UNCORRECTABLE | \
> + ACPI_EINJ_CXL_CACHE_FATAL | \
> + ACPI_EINJ_CXL_MEM_CORRECTABLE | \
> + ACPI_EINJ_CXL_MEM_UNCORRECTABLE | \
> + ACPI_EINJ_CXL_MEM_FATAL)
>
> /*
> * ACPI version 5 provides a SET_ERROR_TYPE_WITH_ADDRESS action.
> @@ -544,8 +551,11 @@ static int einj_error_inject(u32 type, u32 flags, u64 param1, u64 param2,
> if (type & ACPI5_VENDOR_BIT) {
> if (vendor_flags != SETWA_FLAGS_MEM)
> goto inject;
> - } else if (!(type & MEM_ERROR_MASK) && !(flags & SETWA_FLAGS_MEM))
> + } else if (!(type & MEM_ERROR_MASK) && !(flags & SETWA_FLAGS_MEM)) {
> goto inject;
> + } else if ((type & CXL_ERROR_MASK) && (flags & SETWA_FLAGS_MEM)) {
> + goto inject;
> + }
>
> /*
> * Disallow crazy address masks that give BIOS leeway to pick
> @@ -597,6 +607,9 @@ static const char * const einj_error_type_string[] = {
> "0x00000200\tPlatform Correctable\n",
> "0x00000400\tPlatform Uncorrectable non-fatal\n",
> "0x00000800\tPlatform Uncorrectable fatal\n",
> +};
> +
> +static const char * const einj_cxl_error_type_string[] = {
> "0x00001000\tCXL.cache Protocol Correctable\n",
> "0x00002000\tCXL.cache Protocol Uncorrectable non-fatal\n",
> "0x00004000\tCXL.cache Protocol Uncorrectable fatal\n",
> @@ -622,29 +635,44 @@ static int available_error_type_show(struct seq_file *m, void *v)
>
> DEFINE_SHOW_ATTRIBUTE(available_error_type);
>
> -static int error_type_get(void *data, u64 *val)
> +int einj_cxl_available_error_type_show(struct seq_file *m, void *v)
> {
> - *val = error_type;
> + int cxl_err, rc;
> + u32 available_error_type = 0;
> +
> + if (!einj_initialized)
> + return -ENXIO;
> +
> + rc = einj_get_available_error_type(&available_error_type);
> + if (rc)
> + return rc;
> +
> + for (int pos = 0; pos < ARRAY_SIZE(einj_cxl_error_type_string); pos++) {
> + cxl_err = ACPI_EINJ_CXL_CACHE_CORRECTABLE << pos;
> +
> + if (available_error_type & cxl_err)
> + seq_puts(m, einj_cxl_error_type_string[pos]);
> + }
>
> return 0;
> }
> +EXPORT_SYMBOL_NS_GPL(einj_cxl_available_error_type_show, CXL);
>
> -static int error_type_set(void *data, u64 val)
> +static int validate_error_type(u64 type)
> {
> + u32 tval, vendor, available_error_type = 0;
> int rc;
> - u32 available_error_type = 0;
> - u32 tval, vendor;
>
> /* Only low 32 bits for error type are valid */
> - if (val & GENMASK_ULL(63, 32))
> + if (type & GENMASK_ULL(63, 32))
> return -EINVAL;
>
> /*
> * Vendor defined types have 0x80000000 bit set, and
> * are not enumerated by ACPI_EINJ_GET_ERROR_TYPE
> */
> - vendor = val & ACPI5_VENDOR_BIT;
> - tval = val & 0x7fffffff;
> + vendor = type & ACPI5_VENDOR_BIT;
> + tval = type & 0x7fffffff;
>
> /* Only one error type can be specified */
> if (tval & (tval - 1))
> @@ -653,9 +681,105 @@ static int error_type_set(void *data, u64 val)
> rc = einj_get_available_error_type(&available_error_type);
> if (rc)
> return rc;
> - if (!(val & available_error_type))
> + if (!(type & available_error_type))
> return -EINVAL;
> }
> +
> + return 0;
> +}
> +
> +static int cxl_dport_get_sbdf(struct pci_dev *dport_dev, u64 *sbdf)
> +{
> + struct pci_bus *pbus;
> + struct pci_host_bridge *bridge;
> + u64 seg = 0, bus;
> +
> + pbus = dport_dev->bus;
> + bridge = pci_find_host_bridge(pbus);
> +
> + if (!bridge)
> + return -ENODEV;
> +
> + if (bridge->domain_nr != PCI_DOMAIN_NR_NOT_SET)
> + seg = bridge->domain_nr << 24;
> +
> + bus = pbus->number << 16;
> + *sbdf = seg | bus | dport_dev->devfn;
> +
> + return 0;
> +}
> +
> +int einj_cxl_inject_rch_error(u64 rcrb, u64 type)
> +{
> + u64 param1 = 0, param2 = 0, param4 = 0;
> + u32 flags;
> + int rc;
> +
> + if (!einj_initialized)
> + return -ENXIO;
> +
> + /* Only CXL error types can be specified */
> + if (type & ~CXL_ERROR_MASK || (type & ACPI5_VENDOR_BIT))
> + return -EINVAL;
> +
> + rc = validate_error_type(type);
> + if (rc)
> + return rc;
> +
> + param1 = (u64) rcrb;
> + param2 = 0xfffffffffffff000;
> + flags = 0x2;
> +
> + return einj_error_inject(type, flags, param1, param2, 0, param4);
> +}
> +EXPORT_SYMBOL_NS_GPL(einj_cxl_inject_rch_error, CXL);
> +
> +int einj_cxl_inject_error(struct pci_dev *dport, u64 type)
> +{
> + u64 param1 = 0, param2 = 0, param4 = 0;
> + u32 flags;
> + int rc;
> +
> + if (!einj_initialized)
> + return -ENXIO;
> +
> + /* Only CXL error types can be specified */
> + if (type & ~CXL_ERROR_MASK || (type & ACPI5_VENDOR_BIT))
> + return -EINVAL;
> +
> + rc = validate_error_type(type);
> + if (rc)
> + return rc;
> +
> + rc = cxl_dport_get_sbdf(dport, ¶m4);
> + if (rc)
> + return rc;
> +
> + flags = 0x4;
> +
> + return einj_error_inject(type, flags, param1, param2, 0, param4);
> +}
> +EXPORT_SYMBOL_NS_GPL(einj_cxl_inject_error, CXL);
> +
> +static int error_type_get(void *data, u64 *val)
> +{
> + *val = error_type;
> +
> + return 0;
> +}
> +
> +static int error_type_set(void *data, u64 val)
> +{
> + int rc;
> +
> + /* CXL error types have to be injected from cxl debugfs */
> + if (val & CXL_ERROR_MASK && !(val & ACPI5_VENDOR_BIT))
> + return -EINVAL;
> +
> + rc = validate_error_type(val);
> + if (rc)
> + return rc;
> +
> error_type = val;
>
> return 0;
> diff --git a/drivers/cxl/core/port.c b/drivers/cxl/core/port.c
> index 8c00fd6be730..a41618ce380b 100644
> --- a/drivers/cxl/core/port.c
> +++ b/drivers/cxl/core/port.c
> @@ -3,6 +3,7 @@
> #include <linux/platform_device.h>
> #include <linux/memregion.h>
> #include <linux/workqueue.h>
> +#include <linux/einj-cxl.h>
> #include <linux/debugfs.h>
> #include <linux/device.h>
> #include <linux/module.h>
> @@ -797,6 +798,37 @@ static int cxl_dport_setup_regs(struct device *host, struct cxl_dport *dport,
> return rc;
> }
>
> +DEFINE_SHOW_ATTRIBUTE(einj_cxl_available_error_type);
> +
> +static int cxl_einj_inject(void *data, u64 type)
> +{
> + struct cxl_dport *dport = data;
> +
> + if (dport->rch)
> + return einj_cxl_inject_rch_error(dport->rcrb.base, type);
> +
> + return einj_cxl_inject_error(to_pci_dev(dport->dport_dev), type);
> +}
> +DEFINE_DEBUGFS_ATTRIBUTE(cxl_einj_inject_fops, NULL, cxl_einj_inject, "%llx\n");
> +
> +static void cxl_debugfs_create_dport_dir(struct cxl_dport *dport)
> +{
> + struct dentry *dir;
> +
> + /*
> + * dport_dev needs to be a PCIe port for CXL 2.0+ ports because
> + * EINJ expects a dport SBDF to be specified for 2.0 error injection.
> + */
> + if (!IS_ENABLED(CONFIG_CXL_EINJ) ||
> + (!dport->rch && !dev_is_pci(dport->dport_dev)))
> + return;
Perhaps this IS_ENABLED(CONFIG_CXL_EINJ) and the one below should be
replace with a helper that also queries einj_initialized? Such a helper
would naturally have a static inline stub that fails in the
CONFIG_CXL_EINJ=n case, and it otherwise behaves the same as the base
ACPI case where the debugfs files do not appear if init fails.
