[PATCH 4/4 v3] ACPI: extlog: Trace CPER CXL Protocol Error Section

["Fabio M. De Francesco" <fabio.m.de.francesco@linux.intel.com>]

When Firmware First is enabled, BIOS handles errors first and then it makes
them available to the kernel via the Common Platform Error Record (CPER)
sections (UEFI 2.10 Appendix N). Linux parses the CPER sections via one of
two similar paths, either ELOG or GHES. The errors managed by ELOG are
signaled to the BIOS by the I/O Machine Check Architecture (I/O MCA).

Currently, ELOG and GHES show some inconsistencies in how they report to
userspace via trace events.

Therefore, make the two mentioned paths act similarly by tracing the CPER
CXL Protocol Error Section (UEFI v2.10, Appendix N.2.13).

Cc: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Fabio M. De Francesco <fabio.m.de.francesco@linux.intel.com>
---
 drivers/acpi/acpi_extlog.c | 64 ++++++++++++++++++++++++++++++++++++++
 drivers/cxl/core/ras.c     |  6 ++++
 include/cxl/event.h        |  2 ++
 3 files changed, 72 insertions(+)

diff --git a/drivers/acpi/acpi_extlog.c b/drivers/acpi/acpi_extlog.c
index b2928ff297eda..de4f617f32d49 100644
--- a/drivers/acpi/acpi_extlog.c
+++ b/drivers/acpi/acpi_extlog.c
@@ -12,6 +12,7 @@
 #include <linux/ratelimit.h>
 #include <linux/edac.h>
 #include <linux/ras.h>
+#include <cxl/event.h>
 #include <acpi/ghes.h>
 #include <asm/cpu.h>
 #include <asm/mce.h>
@@ -160,6 +161,62 @@ static void extlog_print_pcie(struct cper_sec_pcie *pcie_err,
 	pci_dev_put(pdev);
 }
 
+static void
+extlog_cxl_cper_handle_prot_err(struct cxl_cper_sec_prot_err *prot_err,
+				int severity)
+{
+#ifdef CONFIG_ACPI_APEI_PCIEAER
+	struct cxl_cper_prot_err_work_data wd;
+	u8 *dvsec_start, *cap_start;
+
+	if (!(prot_err->valid_bits & PROT_ERR_VALID_AGENT_ADDRESS)) {
+		pr_err_ratelimited("CXL CPER invalid agent type\n");
+		return;
+	}
+
+	if (!(prot_err->valid_bits & PROT_ERR_VALID_ERROR_LOG)) {
+		pr_err_ratelimited("CXL CPER invalid protocol error log\n");
+		return;
+	}
+
+	if (prot_err->err_len != sizeof(struct cxl_ras_capability_regs)) {
+		pr_err_ratelimited("CXL CPER invalid RAS Cap size (%u)\n",
+				   prot_err->err_len);
+		return;
+	}
+
+	if ((prot_err->agent_type == RCD || prot_err->agent_type == DEVICE ||
+	     prot_err->agent_type == LD || prot_err->agent_type == FMLD) &&
+	    !(prot_err->valid_bits & PROT_ERR_VALID_SERIAL_NUMBER))
+		pr_warn(FW_WARN "CXL CPER no device serial number\n");
+
+	switch (prot_err->agent_type) {
+	case RCD:
+	case DEVICE:
+	case LD:
+	case FMLD:
+	case RP:
+	case DSP:
+	case USP:
+		memcpy(&wd.prot_err, prot_err, sizeof(wd.prot_err));
+
+		dvsec_start = (u8 *)(prot_err + 1);
+		cap_start = dvsec_start + prot_err->dvsec_len;
+
+		memcpy(&wd.ras_cap, cap_start, sizeof(wd.ras_cap));
+		wd.severity = cper_severity_to_aer(severity);
+		break;
+	default:
+		pr_err_ratelimited("CXL CPER reserved agent type: %d\n",
+				   prot_err->agent_type);
+		return;
+	}
+
+	cxl_cper_ras_handle_prot_err(&wd);
+
+#endif
+}
+
 static int extlog_print(struct notifier_block *nb, unsigned long val,
 			void *data)
 {
@@ -211,6 +268,12 @@ static int extlog_print(struct notifier_block *nb, unsigned long val,
 			if (gdata->error_data_length >= sizeof(*mem))
 				trace_extlog_mem_event(mem, err_seq, fru_id, fru_text,
 						       (u8)gdata->error_severity);
+		} else if (guid_equal(sec_type, &CPER_SEC_CXL_PROT_ERR)) {
+			struct cxl_cper_sec_prot_err *prot_err =
+				acpi_hest_get_payload(gdata);
+
+			extlog_cxl_cper_handle_prot_err(prot_err,
+							gdata->error_severity);
 		} else if (guid_equal(sec_type, &CPER_SEC_PCIE)) {
 			struct cper_sec_pcie *pcie_err = acpi_hest_get_payload(gdata);
 
@@ -378,3 +441,4 @@ module_exit(extlog_exit);
 MODULE_AUTHOR("Chen, Gong <gong.chen@intel.com>");
 MODULE_DESCRIPTION("Extended MCA Error Log Driver");
 MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS("CXL");
diff --git a/drivers/cxl/core/ras.c b/drivers/cxl/core/ras.c
index 485a831695c70..56db290c88d35 100644
--- a/drivers/cxl/core/ras.c
+++ b/drivers/cxl/core/ras.c
@@ -98,6 +98,12 @@ static void cxl_cper_handle_prot_err(struct cxl_cper_prot_err_work_data *data)
 		cxl_cper_trace_uncorr_prot_err(pdev, data->ras_cap);
 }
 
+void cxl_cper_ras_handle_prot_err(struct cxl_cper_prot_err_work_data *wd)
+{
+	cxl_cper_handle_prot_err(wd);
+}
+EXPORT_SYMBOL_NS_GPL(cxl_cper_ras_handle_prot_err, "CXL");
+
 static void cxl_cper_prot_err_work_fn(struct work_struct *work)
 {
 	struct cxl_cper_prot_err_work_data wd;
diff --git a/include/cxl/event.h b/include/cxl/event.h
index f9ae1796da85f..aef906e260330 100644
--- a/include/cxl/event.h
+++ b/include/cxl/event.h
@@ -285,4 +285,6 @@ static inline int cxl_cper_prot_err_kfifo_get(struct cxl_cper_prot_err_work_data
 }
 #endif
 
+void cxl_cper_ras_handle_prot_err(struct cxl_cper_prot_err_work_data *wd);
+
 #endif /* _LINUX_CXL_EVENT_H */
-- 
2.49.0