Ira Weiny wrote:
> BIOS can configure memory devices as firmware first. This will send CXL
> events to the firmware instead of the OS. The firmware can then send
> these events to the OS via UEFI.
>
> UEFI v2.10 section N.2.14 defines a Common Platform Error Record (CPER)
> format for CXL Component Events. The format is mostly the same as the
> CXL Common Event Record Format. The only difference is the UUID is
> passed via the Section Type as a GUID and not included as part of the
> record data.
>
> Add EFI support to detect CXL CPER records and call a notifier chain
> with the record data blobs.
>
> Note that the format of a GUID and UUID are not the same. Therefore the
> Section Type GUID defines are duplicated from the CXL code.
>
> Signed-off-by: Ira Weiny <ira.weiny@xxxxxxxxx>
>
> ---
> Changes from RFC v1
> [iweiny: use an enum for know record types and skip converting GUID to UUID]
> [iweiny: commit to the UUID not being part of the event record data]
> [iweiny: use defines for GUID definitions]
> ---
> drivers/firmware/efi/cper.c | 16 +++++++++++
> drivers/firmware/efi/cper_cxl.c | 40 ++++++++++++++++++++++++++++
> drivers/firmware/efi/cper_cxl.h | 29 ++++++++++++++++++++
> include/linux/efi.h | 59 +++++++++++++++++++++++++++++++++++++++++
> 4 files changed, 144 insertions(+)
>
> diff --git a/drivers/firmware/efi/cper.c b/drivers/firmware/efi/cper.c
> index 35c37f667781..d6415c94d584 100644
> --- a/drivers/firmware/efi/cper.c
> +++ b/drivers/firmware/efi/cper.c
> @@ -607,6 +607,22 @@ cper_estatus_print_section(const char *pfx, struct acpi_hest_generic_data *gdata
> cper_print_prot_err(newpfx, prot_err);
> else
> goto err_section_too_small;
> + } else if (guid_equal(sec_type, &CPER_SEC_CXL_GEN_MEDIA) ||
> + guid_equal(sec_type, &CPER_SEC_CXL_DRAM) ||
> + guid_equal(sec_type, &CPER_SEC_CXL_MEM_MODULE)) {
> + struct cper_cxl_event_rec *rec = acpi_hest_get_payload(gdata);
> +
> + printk("%ssection type: CXL Event\n", newpfx);
I would say that since this is going to be hanlded elsewhere the kernel
log can stay silent.
> +
> + if (rec->hdr.length <= sizeof(rec->hdr))
> + goto err_section_too_small;
> +
> + if (rec->hdr.length > sizeof(*rec)) {
> + pr_err(FW_WARN "error section length is too big\n");
> + return;
> + }
> +
> + cper_post_cxl_event(newpfx, sec_type, rec);
> } else {
> const void *err = acpi_hest_get_payload(gdata);
>
> diff --git a/drivers/firmware/efi/cper_cxl.c b/drivers/firmware/efi/cper_cxl.c
> index a55771b99a97..04234884898d 100644
> --- a/drivers/firmware/efi/cper_cxl.c
> +++ b/drivers/firmware/efi/cper_cxl.c
> @@ -187,3 +187,43 @@ void cper_print_prot_err(const char *pfx, const struct cper_sec_prot_err *prot_e
> sizeof(cxl_ras->header_log), 0);
> }
> }
> +
> +/* CXL CPER notifier chain */
> +static BLOCKING_NOTIFIER_HEAD(cxl_cper_chain_head);
> +
> +void cper_post_cxl_event(const char *pfx, guid_t *sec_type,
> + struct cper_cxl_event_rec *rec)
> +{
> + struct cxl_cper_notifier_data nd = {
> + .rec = rec,
> + };
> +
> + if (!(rec->hdr.validation_bits & CPER_CXL_COMP_EVENT_LOG_VALID)) {
> + pr_err(FW_WARN "cxl event no Component Event Log present\n");
> + return;
> + }
> +
> + if (guid_equal(sec_type, &CPER_SEC_CXL_GEN_MEDIA))
> + nd.cper_event = CXL_CPER_EVENT_GEN_MEDIA;
> + else if (guid_equal(sec_type, &CPER_SEC_CXL_DRAM))
> + nd.cper_event = CXL_CPER_EVENT_DRAM;
> + else if (guid_equal(sec_type, &CPER_SEC_CXL_MEM_MODULE))
> + nd.cper_event = CXL_CPER_EVENT_MEM_MODULE;
> +
> + if (blocking_notifier_call_chain(&cxl_cper_chain_head, 0, (void *)&nd)
> + == NOTIFY_BAD)
> + pr_err(FW_WARN "cxl event notifier chain failed\n");
> +}
> +
> +int register_cxl_cper_notifier(struct notifier_block *nb)
> +{
> + return blocking_notifier_chain_register(&cxl_cper_chain_head, nb);
> +}
> +EXPORT_SYMBOL(register_cxl_cper_notifier);
I think this should be EXPORT_SYMBOL_NS_GPL(..., CXL) since I can't
imagine a third-party driver use case for this.
> +
> +void unregister_cxl_cper_notifier(struct notifier_block *nb)
> +{
> + blocking_notifier_chain_unregister(&cxl_cper_chain_head, nb);
> +}
> +EXPORT_SYMBOL(unregister_cxl_cper_notifier);
> +
> diff --git a/drivers/firmware/efi/cper_cxl.h b/drivers/firmware/efi/cper_cxl.h
> index 86bfcf7909ec..ca26126cd9b8 100644
> --- a/drivers/firmware/efi/cper_cxl.h
> +++ b/drivers/firmware/efi/cper_cxl.h
> @@ -10,11 +10,38 @@
> #ifndef LINUX_CPER_CXL_H
> #define LINUX_CPER_CXL_H
>
> +#include <linux/efi.h>
> +
> /* CXL Protocol Error Section */
> #define CPER_SEC_CXL_PROT_ERR \
> GUID_INIT(0x80B9EFB4, 0x52B5, 0x4DE3, 0xA7, 0x77, 0x68, 0x78, \
> 0x4B, 0x77, 0x10, 0x48)
>
> +/* CXL Event record UUIDs are used as the section type */
> +/*
> + * General Media Event Record
> + * CXL rev 3.0 Section 8.2.9.2.1.1; Table 8-43
> + */
> +#define CPER_SEC_CXL_GEN_MEDIA \
> + GUID_INIT(0xfbcd0a77, 0xc260, 0x417f, \
> + 0x85, 0xa9, 0x08, 0x8b, 0x16, 0x21, 0xeb, 0xa6)
> +
> +/*
> + * DRAM Event Record
> + * CXL rev 3.0 section 8.2.9.2.1.2; Table 8-44
> + */
> +#define CPER_SEC_CXL_DRAM \
> + GUID_INIT(0x601dcbb3, 0x9c06, 0x4eab, \
> + 0xb8, 0xaf, 0x4e, 0x9b, 0xfb, 0x5c, 0x96, 0x24)
> +
> +/*
> + * Memory Module Event Record
> + * CXL rev 3.0 section 8.2.9.2.1.3; Table 8-45
> + */
> +#define CPER_SEC_CXL_MEM_MODULE \
> + GUID_INIT(0xfe927475, 0xdd59, 0x4339, \
> + 0xa5, 0x86, 0x79, 0xba, 0xb1, 0x13, 0xb7, 0x74)
> +
> #pragma pack(1)
>
> /* Compute Express Link Protocol Error Section, UEFI v2.10 sec N.2.13 */
> @@ -62,5 +89,7 @@ struct cper_sec_prot_err {
> #pragma pack()
>
> void cper_print_prot_err(const char *pfx, const struct cper_sec_prot_err *prot_err);
> +void cper_post_cxl_event(const char *pfx, guid_t *sec_type,
> + struct cper_cxl_event_rec *rec);
>
> #endif //__CPER_CXL_
> diff --git a/include/linux/efi.h b/include/linux/efi.h
> index 80b21d1c6eaf..b5b8b46c8deb 100644
> --- a/include/linux/efi.h
> +++ b/include/linux/efi.h
> @@ -1355,4 +1355,63 @@ bool efi_config_table_is_usable(const efi_guid_t *guid, unsigned long table)
>
> umode_t efi_attr_is_visible(struct kobject *kobj, struct attribute *attr, int n);
>
> +/*
> + * Event log size adjusted for CPER
> + *
> + * Base table from CXL r3.0 Table 8-42: (30h + 50h)
> + * For lack of UUID: - 10h
> + *
> + * (30h + 50h) - 10h = 70h
> + */
> +#define CPER_CXL_COMP_EVENT_LOG_SIZE 0x70
> +#define CPER_CXL_DEVICE_ID_VALID BIT(0)
> +#define CPER_CXL_DEVICE_SN_VALID BIT(1)
> +#define CPER_CXL_COMP_EVENT_LOG_VALID BIT(2)
> +struct cper_cxl_event_rec {
> + struct {
> + u32 length;
> + u64 validation_bits;
> + struct {
> + u16 vendor_id;
> + u16 device_id;
> + u8 func_num;
> + u8 device_num;
> + u8 bus_num;
> + u16 segment_num;
> + u16 slot_num; /* bits 2:0 reserved */
> + u8 reserved;
> + } device_id;
> + struct {
> + u32 lower_dw;
> + u32 upper_dw;
> + } dev_serial_num;
> + } hdr;
> +
> + u8 comp_event_log[CPER_CXL_COMP_EVENT_LOG_SIZE];
Rather than define CPER_CXL_COMP_EVENT_LOG_SIZE I would prefer that CXL
and EFI share a common struct definition for these common fields.
That would also remove the need for BUILD_BUG_ON() since they literally
can not disagree on the size in that case.
> +};
> +#define CPER_CXL_REC_LEN(rec) (rec->hdr.length - sizeof(rec->hdr))
> +
> +enum cxl_cper_event {
> + CXL_CPER_EVENT_GEN_MEDIA,
> + CXL_CPER_EVENT_DRAM,
> + CXL_CPER_EVENT_MEM_MODULE,
> +};
It follows from defining that common data structure above that this enum
would be a generic CXL namespace that drops "_CPER_". I.e. the CPER
notification handler and the native driver translate the event to this
common generic sub-structure that gets emitted.
> +
> +struct cxl_cper_notifier_data {
> + enum cxl_cper_event cper_event;
> + struct cper_cxl_event_rec *rec;
> +};
> +
> +#ifdef CONFIG_EFI
> +int register_cxl_cper_notifier(struct notifier_block *nb);
> +void unregister_cxl_cper_notifier(struct notifier_block *nb);
> +#else
> +static inline int register_cxl_cper_notifier(struct notifier_block *nb)
> +{
> + return 0;
> +}
> +
> +static inline void unregister_cxl_cper_notifier(struct notifier_block *nb) { }
> +#endif
> +
> #endif /* _LINUX_EFI_H */
>
> --
> 2.41.0
>
