efi/cper, cxl: Decode CXL Protocol Error Section

Add support for decoding CXL Protocol Error Section as defined in UEFI 2.10
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.
Signed-off-by: Smita Koralahalli <Smita.KoralahalliChannabasappa@amd.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>

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_WRAPPERS)	+= runtime-wrappers.o
 subdir-$(CONFIG_EFI_STUB)		+= libstub
 obj-$(CONFIG_EFI_BOOTLOADER_CONTROL)	+= efibc.o

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);
 

drivers/firmware/efi/cper_cxl.c

+// 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 Downstream Port",
+	"CXL Device",
+	"CXL Logical Device",
+	"CXL Fabric Manager managed Logical Device",
+	"CXL Root Port",
+	"CXL Downstream Switch Port",
+	"CXL Upstream Switch Port",
+};
+
+/*
+ * The layout of the enumeration and the values matches CXL Agent Type
+ * field in the UEFI 2.10 Section N.2.13,
+ */
+enum {
+	RCD,	/* Restricted CXL Device */
+	RCH_DP,	/* Restricted CXL Host Downstream Port */
+	DEVICE,	/* CXL Device */
+	LD,	/* CXL Logical Device */
+	FMLD,	/* CXL Fabric Manager managed Logical Device */
+	RP,	/* CXL Root Port */
+	DSP,	/* CXL Downstream Switch Port */
+	USP,	/* CXL Upstream Switch Port */
+};
+
+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) {
+		/*
+		 * According to UEFI 2.10 Section N.2.13, the term CXL Device
+		 * is used to refer to Restricted CXL Device, CXL Device, CXL
+		 * Logical Device or a CXL Fabric Manager Managed Logical
+		 * Device.
+		 */
+		case RCD:
+		case DEVICE:
+		case LD:
+		case FMLD:
+		case RP:
+		case DSP:
+		case USP:
+			pr_info("%s agent_address: %04x:%02x:%02x.%x\n",
+				pfx, prot_err->agent_addr.segment,
+				prot_err->agent_addr.bus,
+				prot_err->agent_addr.device,
+				prot_err->agent_addr.function);
+			break;
+		case RCH_DP:
+			pr_info("%s rcrb_base_address: 0x%016llx\n", pfx,
+				prot_err->agent_addr.rcrb_base_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:
+		case DEVICE:
+		case LD:
+		case FMLD:
+		case RP:
+		case DSP:
+		case USP:
+			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.subsystem_vendor_id,
+				prot_err->device_id.subsystem_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:
+		case DEVICE:
+		case LD:
+		case FMLD:
+			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;
+		}
+	}
+
+	if (prot_err->valid_bits & PROT_ERR_VALID_CAPABILITY) {
+		switch (prot_err->agent_type) {
+		case RCD:
+		case DEVICE:
+		case LD:
+		case FMLD:
+		case RP:
+		case DSP:
+		case USP:
+			print_hex_dump(pfx, "", DUMP_PREFIX_OFFSET, 16, 4,
+				       prot_err->capability,
+				       sizeof(prot_err->capability), 0);
+			break;
+		default:
+			break;
+		}
+	}
+
+	if (prot_err->valid_bits & PROT_ERR_VALID_DVSEC) {
+		pr_info("%s DVSEC length: 0x%04x\n", pfx, prot_err->dvsec_len);
+
+		pr_info("%s CXL DVSEC:\n", pfx);
+		print_hex_dump(pfx, "", DUMP_PREFIX_OFFSET, 16, 4, (prot_err + 1),
+			       prot_err->dvsec_len, 0);
+	}
+}

drivers/firmware/efi/cper_cxl.h

+/* 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 v2.10 sec N.2.13 */
+struct cper_sec_prot_err {
+	u64 valid_bits;
+	u8 agent_type;
+	u8 reserved[7];
+
+	/*
+	 * Except for RCH Downstream Port, all the remaining CXL Agent
+	 * types are uniquely identified by the PCIe compatible SBDF number.
+	 */
+	union {
+		u64 rcrb_base_addr;
+		struct {
+			u8 function;
+			u8 device;
+			u8 bus;
+			u16 segment;
+			u8 reserved_1[3];
+		};
+	} agent_addr;
+
+	struct {
+		u16 vendor_id;
+		u16 device_id;
+		u16 subsystem_vendor_id;
+		u16 subsystem_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_