[PATCH 1/2] efi/cper, cxl: Decode CXL Protocol Error Section

[Smita Koralahalli <Smita.KoralahalliChannabasappa@amd.com>]

Add support for decoding CXL Protocol Error Section as defined in UEFI 2.9
Section N.2.13.

Do the section decoding in a new cper_cxl.c file. This new file will be
used in the future for more CXL CPERs decode support. Add this to the
existing UEFI_CPER config.

Decode only the fields that are useful to parse the error.

Signed-off-by: Smita Koralahalli <Smita.KoralahalliChannabasappa@amd.com>
---
 drivers/firmware/efi/Makefile   |  2 +-
 drivers/firmware/efi/cper.c     |  9 ++++
 drivers/firmware/efi/cper_cxl.c | 87 +++++++++++++++++++++++++++++++++
 drivers/firmware/efi/cper_cxl.h | 58 ++++++++++++++++++++++
 4 files changed, 155 insertions(+), 1 deletion(-)
 create mode 100644 drivers/firmware/efi/cper_cxl.c
 create mode 100644 drivers/firmware/efi/cper_cxl.h

diff --git a/drivers/firmware/efi/Makefile b/drivers/firmware/efi/Makefile
index 8d151e332584..4f332de54173 100644
--- a/drivers/firmware/efi/Makefile
+++ b/drivers/firmware/efi/Makefile
@@ -19,7 +19,7 @@ endif
 obj-$(CONFIG_EFI_PARAMS_FROM_FDT)	+= fdtparams.o
 obj-$(CONFIG_EFI_ESRT)			+= esrt.o
 obj-$(CONFIG_EFI_VARS_PSTORE)		+= efi-pstore.o
-obj-$(CONFIG_UEFI_CPER)			+= cper.o
+obj-$(CONFIG_UEFI_CPER)			+= cper.o cper_cxl.o
 obj-$(CONFIG_EFI_RUNTIME_MAP)		+= runtime-map.o
 obj-$(CONFIG_EFI_RUNTIME_WRAPPERS)	+= runtime-wrappers.o
 subdir-$(CONFIG_EFI_STUB)		+= libstub
diff --git a/drivers/firmware/efi/cper.c b/drivers/firmware/efi/cper.c
index e4e5ea7ce910..181deb9af527 100644
--- a/drivers/firmware/efi/cper.c
+++ b/drivers/firmware/efi/cper.c
@@ -24,6 +24,7 @@
 #include <linux/bcd.h>
 #include <acpi/ghes.h>
 #include <ras/ras_event.h>
+#include "cper_cxl.h"
 
 /*
  * CPER record ID need to be unique even after reboot, because record
@@ -595,6 +596,14 @@ cper_estatus_print_section(const char *pfx, struct acpi_hest_generic_data *gdata
 			cper_print_fw_err(newpfx, gdata, fw_err);
 		else
 			goto err_section_too_small;
+	} else if (guid_equal(sec_type, &CPER_SEC_CXL_PROT_ERR)) {
+		struct cper_sec_prot_err *prot_err = acpi_hest_get_payload(gdata);
+
+		printk("%ssection_type: CXL Protocol Error\n", newpfx);
+		if (gdata->error_data_length >= sizeof(*prot_err))
+			cper_print_prot_err(newpfx, prot_err);
+		else
+			goto err_section_too_small;
 	} 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
new file mode 100644
index 000000000000..e5f48f0de1a4
--- /dev/null
+++ b/drivers/firmware/efi/cper_cxl.c
@@ -0,0 +1,87 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * UEFI Common Platform Error Record (CPER) support for CXL Section.
+ *
+ * Copyright (C) 2022 Advanced Micro Devices, Inc.
+ *
+ * Author: Smita Koralahalli <Smita.KoralahalliChannabasappa@amd.com>
+ */
+
+#include <linux/cper.h>
+#include "cper_cxl.h"
+
+#define PROT_ERR_VALID_AGENT_TYPE		BIT_ULL(0)
+#define PROT_ERR_VALID_AGENT_ADDRESS		BIT_ULL(1)
+#define PROT_ERR_VALID_DEVICE_ID		BIT_ULL(2)
+#define PROT_ERR_VALID_SERIAL_NUMBER		BIT_ULL(3)
+#define PROT_ERR_VALID_CAPABILITY		BIT_ULL(4)
+#define PROT_ERR_VALID_DVSEC			BIT_ULL(5)
+
+static const char * const prot_err_agent_type_strs[] = {
+	"Restricted CXL Device",
+	"Restricted CXL Host DP",
+};
+
+enum {
+	RCD,
+	RCH_DP,
+};
+
+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)
+		pr_info("%s agent_type: %d, %s\n", pfx, prot_err->agent_type,
+			prot_err->agent_type < ARRAY_SIZE(prot_err_agent_type_strs)
+			? prot_err_agent_type_strs[prot_err->agent_type]
+			: "unknown");
+
+	if (prot_err->valid_bits & PROT_ERR_VALID_AGENT_ADDRESS) {
+		switch (prot_err->agent_type) {
+		case RCD:
+			pr_info("%s agent_address: %04x:%02x:%02x.%x\n",
+				pfx, prot_err->segment, prot_err->bus,
+				prot_err->device, prot_err->function);
+			break;
+		case RCH_DP:
+			pr_info("%s rcrb_base_address: 0x%016llx\n", pfx,
+				prot_err->agent_addr);
+			break;
+		default:
+			break;
+		}
+	}
+
+	if (prot_err->valid_bits & PROT_ERR_VALID_DEVICE_ID) {
+		const __u8 *class_code;
+
+		switch (prot_err->agent_type) {
+		case RCD:
+			pr_info("%s slot: %d\n", pfx,
+				prot_err->device_id.slot >> CPER_PCIE_SLOT_SHIFT);
+			pr_info("%s vendor_id: 0x%04x, device_id: 0x%04x\n",
+				pfx, prot_err->device_id.vendor_id,
+				prot_err->device_id.device_id);
+			pr_info("%s sub_vendor_id: 0x%04x, sub_device_id: 0x%04x\n",
+				pfx, prot_err->device_id.sub_vendor_id,
+				prot_err->device_id.sub_device_id);
+			class_code = prot_err->device_id.class_code;
+			pr_info("%s class_code: %02x%02x\n", pfx,
+				class_code[1], class_code[0]);
+			break;
+		default:
+			break;
+		}
+	}
+
+	if (prot_err->valid_bits & PROT_ERR_VALID_SERIAL_NUMBER) {
+		switch (prot_err->agent_type) {
+		case RCD:
+			pr_info("%s lower_dw: 0x%08x, upper_dw: 0x%08x\n", pfx,
+				prot_err->dev_serial_num.lower_dw,
+				prot_err->dev_serial_num.upper_dw);
+			break;
+		default:
+			break;
+		}
+	}
+}
diff --git a/drivers/firmware/efi/cper_cxl.h b/drivers/firmware/efi/cper_cxl.h
new file mode 100644
index 000000000000..f924d96e4bb2
--- /dev/null
+++ b/drivers/firmware/efi/cper_cxl.h
@@ -0,0 +1,58 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * UEFI Common Platform Error Record (CPER) support for CXL Section.
+ *
+ * Copyright (C) 2022 Advanced Micro Devices, Inc.
+ *
+ * Author: Smita Koralahalli <Smita.KoralahalliChannabasappa@amd.com>
+ */
+
+#ifndef LINUX_CPER_CXL_H
+#define LINUX_CPER_CXL_H
+
+/* CXL Protocol Error Section */
+#define CPER_SEC_CXL_PROT_ERR						\
+	GUID_INIT(0x80B9EFB4, 0x52B5, 0x4DE3, 0xA7, 0x77, 0x68, 0x78,	\
+		  0x4B, 0x77, 0x10, 0x48)
+
+#pragma pack(1)
+
+/* Compute Express Link Protocol Error Section, UEFI v2.9 sec N.2.13 */
+struct cper_sec_prot_err {
+	u64			valid_bits;
+	u8			agent_type;
+	u8			reserved[7];
+	union {
+		u64		agent_addr;
+		struct {
+			u8	function;
+			u8	device;
+			u8	bus;
+			u16	segment;
+			u8	reserved_1[3];
+		};
+	};
+	struct {
+		u16		vendor_id;
+		u16		device_id;
+		u16		sub_vendor_id;
+		u16		sub_device_id;
+		u8		class_code[2];
+		u16		slot;
+		u8		reserved_1[4];
+	}			device_id;
+	struct {
+		u32		lower_dw;
+		u32		upper_dw;
+	}			dev_serial_num;
+	u8			capability[60];
+	u16			dvsec_len;
+	u16			err_len;
+	u8			reserved_2[4];
+};
+
+#pragma pack()
+
+void cper_print_prot_err(const char *pfx, const struct cper_sec_prot_err *prot_err);
+
+#endif //__CPER_CXL_
-- 
2.17.1