[PATCH v2 3/4] acpi/ghes, efi/cper: Recognize and process CXL Protocol Errors.

[Smita Koralahalli]

UEFI v2.10 section N.2.13 defines a CPER record for CXL Protocol errors.

Add GHES support to detect CXL CPER Protocol record and cache error
severity, device_id, serial number and CXL RAS capability struct in
struct cxl_cper_event_info.

Signed-off-by: Smita Koralahalli <Smita.KoralahalliChannabasappa@xxxxxxx>
---
v2:
	Change to sub-struct for protocol error specific elemenets.
	Set serial number unconditionally.
	Copy entire cxl_ras_capability_regs struct rather than pointer.
	Calculate error severity in efi/cper and change to enum.
---
 drivers/acpi/apei/ghes.c        | 11 ++++++
 drivers/firmware/efi/cper_cxl.c | 68 +++++++++++++++++++++++++++++++++
 include/linux/cxl-event.h       | 13 +++++++
 3 files changed, 92 insertions(+)

diff --git a/drivers/acpi/apei/ghes.c b/drivers/acpi/apei/ghes.c
index 60b615d361d3..1d4f3d68a0bc 100644
--- a/drivers/acpi/apei/ghes.c
+++ b/drivers/acpi/apei/ghes.c
@@ -714,6 +714,14 @@ static void cxl_cper_post_event(enum cxl_event_type event_type,
 		cper_callback(event_type, &info);
 }
 
+void cxl_cper_handle_prot_err(struct acpi_hest_generic_data *gdata)
+{
+	struct cxl_cper_event_info info;
+
+	if (cxl_cper_handle_prot_err_info(gdata, &info))
+		return;
+}
+
 int cxl_cper_register_callback(cxl_cper_callback callback)
 {
 	guard(rwsem_write)(&cxl_cper_rw_sem);
@@ -768,6 +776,9 @@ static bool ghes_do_proc(struct ghes *ghes,
 		else if (guid_equal(sec_type, &CPER_SEC_PROC_ARM)) {
 			queued = ghes_handle_arm_hw_error(gdata, sev);
 		}
+		else if (guid_equal(sec_type, &CPER_SEC_CXL_PROT_ERR)) {
+			cxl_cper_handle_prot_err(gdata);
+		}
 		else if (guid_equal(sec_type, &CPER_SEC_CXL_GEN_MEDIA_GUID)) {
 			struct cxl_cper_event_rec *rec = acpi_hest_get_payload(gdata);
 
diff --git a/drivers/firmware/efi/cper_cxl.c b/drivers/firmware/efi/cper_cxl.c
index 4fd8d783993e..9b9b8c8f1157 100644
--- a/drivers/firmware/efi/cper_cxl.c
+++ b/drivers/firmware/efi/cper_cxl.c
@@ -8,6 +8,7 @@
  */
 
 #include <linux/cper.h>
+#include <acpi/ghes.h>
 #include "cper_cxl.h"
 
 #define PROT_ERR_VALID_AGENT_TYPE		BIT_ULL(0)
@@ -44,6 +45,17 @@ enum {
 	USP,	/* CXL Upstream Switch Port */
 };
 
+static enum cxl_aer_err_type cper_severity_cxl_aer(int cper_severity)
+{
+	switch (cper_severity) {
+	case CPER_SEV_RECOVERABLE:
+	case CPER_SEV_FATAL:
+		return CXL_AER_UNCORRECTABLE;
+	default:
+		return CXL_AER_CORRECTABLE;
+	}
+}
+
 void cper_print_prot_err(const char *pfx, const struct cper_sec_prot_err *prot_err)
 {
 	if (prot_err->valid_bits & PROT_ERR_VALID_AGENT_TYPE)
@@ -176,3 +188,59 @@ void cper_print_prot_err(const char *pfx, const struct cper_sec_prot_err *prot_e
 			       sizeof(cxl_ras->header_log), 0);
 	}
 }
+
+int cxl_cper_handle_prot_err_info(struct acpi_hest_generic_data *gdata,
+				  struct cxl_cper_event_info *info)
+{
+	struct cper_sec_prot_err *prot_err = acpi_hest_get_payload(gdata);
+	struct cper_cxl_event_devid *device_id = &info->rec.hdr.device_id;
+	struct cper_cxl_event_sn *dev_serial_num =  &info->rec.hdr.dev_serial_num;
+	size_t size = sizeof(*prot_err) + prot_err->dvsec_len;
+
+	if (!(prot_err->valid_bits & PROT_ERR_VALID_ERROR_LOG)) {
+		pr_err(FW_WARN "Not a valid protocol error log\n");
+		return -EINVAL;
+	}
+
+	if (!(prot_err->valid_bits & PROT_ERR_VALID_DEVICE_ID)) {
+		pr_err(FW_WARN "Not a valid Device ID\n");
+		return -EINVAL;
+	}
+
+	/*
+	 * Set device serial number unconditionally.
+	 *
+	 * Print a warning message if it is not valid. The device serial
+	 * number is considered valid for CXL 1.1 device, CXL 2.0 device,
+	 * CXL 2.0 Logical device, or CXL 2.0 Fabric Manager Managed
+	 * Logical Device.
+	 */
+	if (!(prot_err->valid_bits & PROT_ERR_VALID_SERIAL_NUMBER) ||
+	      prot_err->agent_type > 0x4 || prot_err->agent_type == RCH_DP)
+		pr_warn(FW_WARN "Not a valid serial number\n");
+
+	dev_serial_num->lower_dw = prot_err->dev_serial_num.lower_dw;
+	dev_serial_num->upper_dw = prot_err->dev_serial_num.upper_dw;
+
+	/*
+	 * The device ID or agent address is only valid for CXL 1.1 device,
+	 * CXL 2.0 device, CXL 2.0 Logical device, CXL 2.0 Fabric Manager
+	 * Managed Logical Device, CXL Root Port, CXL Downstream Switch
+	 * Port, or CXL Upstream Switch Port.
+	 */
+	if (prot_err->agent_type <= 0x7 && prot_err->agent_type != RCH_DP) {
+		device_id->segment_num = prot_err->agent_addr.segment;
+		device_id->bus_num = prot_err->agent_addr.bus;
+		device_id->device_num = prot_err->agent_addr.device;
+		device_id->func_num = prot_err->agent_addr.function;
+	} else {
+		pr_err(FW_WARN "Not a valid agent type\n");
+		return -EINVAL;
+	}
+
+	info->p_err.cxl_ras = *(struct cxl_ras_capability_regs *)((long)prot_err + size);
+
+	info->p_err.severity = cper_severity_cxl_aer(gdata->error_severity);
+
+	return 0;
+}
diff --git a/include/linux/cxl-event.h b/include/linux/cxl-event.h
index 3a41dd5723e8..08e3979de9a3 100644
--- a/include/linux/cxl-event.h
+++ b/include/linux/cxl-event.h
@@ -152,13 +152,26 @@ struct cxl_ras_capability_regs {
 	u32 header_log[16];
 };
 
+enum cxl_aer_err_type {
+	CXL_AER_UNCORRECTABLE,
+	CXL_AER_CORRECTABLE,
+};
+
 struct cxl_cper_event_info {
 	struct cxl_cper_event_rec rec;
+	struct cxl_cper_prot_err {
+		struct cxl_ras_capability_regs cxl_ras;
+		int severity;
+	} p_err;
 };
 
 typedef void (*cxl_cper_callback)(enum cxl_event_type type,
 				  struct cxl_cper_event_info *info);
 
+struct acpi_hest_generic_data;
+int cxl_cper_handle_prot_err_info(struct acpi_hest_generic_data *gdata,
+				  struct cxl_cper_event_info *info);
+
 #ifdef CONFIG_ACPI_APEI_GHES
 int cxl_cper_register_callback(cxl_cper_callback callback);
 int cxl_cper_unregister_callback(cxl_cper_callback callback);
-- 
2.17.1