efi/cper: align ARM CPER type with UEFI 2.9A/2.10 specs

Up to UEFI spec 2.9, the type byte of CPER struct for ARM processor
was defined simply as:

Type at byte offset 4:

- Cache error
- TLB Error
- Bus Error
- Micro-architectural Error
All other values are reserved

Yet, there was no information about how this would be encoded.

Spec 2.9A errata corrected it by defining:

- Bit 1 - Cache Error
- Bit 2 - TLB Error
- Bit 3 - Bus Error
- Bit 4 - Micro-architectural Error
All other values are reserved

That actually aligns with the values already defined on older
versions at N.2.4.1. Generic Processor Error Section.

Spec 2.10 also preserve the same encoding as 2.9A.

Adjust CPER and GHES handling code for both generic and ARM
processors to properly handle UEFI 2.9A and 2.10 encoding.

Link: https://uefi.org/specs/UEFI/2.10/Apx_N_Common_Platform_Error_Record.html#arm-processor-error-information
Signed-off-by: Mauro Carvalho Chehab <[e-mail]>
Reviewed-by: Jonathan Cameron <[e-mail]>
Acked-by: Borislav Petkov (AMD) <[e-mail]>
Signed-off-by: Ard Biesheuvel <[e-mail]>

drivers/acpi/apei/ghes.c

···
 #include <linux/moduleparam.h>
 #include <linux/init.h>
 #include <linux/acpi.h>
+#include <linux/bitfield.h>
 #include <linux/io.h>
 #include <linux/interrupt.h>
 #include <linux/timer.h>
···
 {
 	struct cper_sec_proc_arm *err = acpi_hest_get_payload(gdata);
 	int flags = sync ? MF_ACTION_REQUIRED : 0;
+	char error_type[120];
 	bool queued = false;
 	int sec_sev, i;
 	char *p;
···
 	p = (char *)(err + 1);
 	for (i = 0; i < err->err_info_num; i++) {
 		struct cper_arm_err_info *err_info = (struct cper_arm_err_info *)p;
-		bool is_cache = (err_info->type == CPER_ARM_CACHE_ERROR);
+		bool is_cache = err_info->type & CPER_ARM_CACHE_ERROR;
 		bool has_pa = (err_info->validation_bits & CPER_ARM_INFO_VALID_PHYSICAL_ADDR);
-		const char *error_type = "unknown error";
 
 		/*
 		 * The field (err_info->error_info & BIT(26)) is fixed to set to
···
 			continue;
 		}
 
-		if (err_info->type < ARRAY_SIZE(cper_proc_error_type_strs))
-			error_type = cper_proc_error_type_strs[err_info->type];
+		cper_bits_to_str(error_type, sizeof(error_type),
+				 FIELD_GET(CPER_ARM_ERR_TYPE_MASK, err_info->type),
+				 cper_proc_error_type_strs,
+				 ARRAY_SIZE(cper_proc_error_type_strs));
 
 		pr_warn_ratelimited(FW_WARN GHES_PFX
-				    "Unhandled processor error type: %s\n",
-				    error_type);
+				    "Unhandled processor error type 0x%02x: %s%s\n",
+				    err_info->type, error_type,
+				    (err_info->type & ~CPER_ARM_ERR_TYPE_MASK) ? " with reserved bit(s)" : "");
 		p += err_info->length;
 	}
 

drivers/firmware/efi/cper-arm.c

···
 	bool proc_context_corrupt, corrected, precise_pc, restartable_pc;
 	bool time_out, access_mode;
 
-	/* If the type is unknown, bail. */
-	if (type > CPER_ARM_MAX_TYPE)
-		return;
-
 	/*
 	 * Vendor type errors have error information values that are vendor
 	 * specific.
 	 */
-	if (type == CPER_ARM_VENDOR_ERROR)
+	if (type & CPER_ARM_VENDOR_ERROR)
 		return;
 
 	if (error_info & CPER_ARM_ERR_VALID_TRANSACTION_TYPE) {
···
 	if (error_info & CPER_ARM_ERR_VALID_OPERATION_TYPE) {
 		op_type = ((error_info >> CPER_ARM_ERR_OPERATION_SHIFT)
 			   & CPER_ARM_ERR_OPERATION_MASK);
-		switch (type) {
-		case CPER_ARM_CACHE_ERROR:
+		if (type & CPER_ARM_CACHE_ERROR) {
 			if (op_type < ARRAY_SIZE(arm_cache_err_op_strs)) {
-				printk("%soperation type: %s\n", pfx,
+				printk("%scache error, operation type: %s\n", pfx,
 				       arm_cache_err_op_strs[op_type]);
 			}
-			break;
-		case CPER_ARM_TLB_ERROR:
+		}
+		if (type & CPER_ARM_TLB_ERROR) {
 			if (op_type < ARRAY_SIZE(arm_tlb_err_op_strs)) {
-				printk("%soperation type: %s\n", pfx,
+				printk("%sTLB error, operation type: %s\n", pfx,
 				       arm_tlb_err_op_strs[op_type]);
 			}
-			break;
-		case CPER_ARM_BUS_ERROR:
+		}
+		if (type & CPER_ARM_BUS_ERROR) {
 			if (op_type < ARRAY_SIZE(arm_bus_err_op_strs)) {
-				printk("%soperation type: %s\n", pfx,
+				printk("%sbus error, operation type: %s\n", pfx,
 				       arm_bus_err_op_strs[op_type]);
 			}
-			break;
 		}
 	}
 
 	if (error_info & CPER_ARM_ERR_VALID_LEVEL) {
 		level = ((error_info >> CPER_ARM_ERR_LEVEL_SHIFT)
 			 & CPER_ARM_ERR_LEVEL_MASK);
-		switch (type) {
-		case CPER_ARM_CACHE_ERROR:
+		if (type & CPER_ARM_CACHE_ERROR)
 			printk("%scache level: %d\n", pfx, level);
-			break;
-		case CPER_ARM_TLB_ERROR:
+
+		if (type & CPER_ARM_TLB_ERROR)
 			printk("%sTLB level: %d\n", pfx, level);
-			break;
-		case CPER_ARM_BUS_ERROR:
+
+		if (type & CPER_ARM_BUS_ERROR)
 			printk("%saffinity level at which the bus error occurred: %d\n",
 			       pfx, level);
-			break;
-		}
 	}
 
 	if (error_info & CPER_ARM_ERR_VALID_PROC_CONTEXT_CORRUPT) {
···
 	struct cper_arm_err_info *err_info;
 	struct cper_arm_ctx_info *ctx_info;
 	char newpfx[64], infopfx[ARRAY_SIZE(newpfx) + 1];
+	char error_type[120];
 
 	printk("%sMIDR: 0x%016llx\n", pfx, proc->midr);
 
···
 				       newpfx);
 		}
 
-		printk("%serror_type: %d, %s\n", newpfx, err_info->type,
-			err_info->type < ARRAY_SIZE(cper_proc_error_type_strs) ?
-			cper_proc_error_type_strs[err_info->type] : "unknown");
+		cper_bits_to_str(error_type, sizeof(error_type),
+				 FIELD_GET(CPER_ARM_ERR_TYPE_MASK, err_info->type),
+				 cper_proc_error_type_strs,
+				 ARRAY_SIZE(cper_proc_error_type_strs));
+
+		printk("%serror_type: 0x%02x: %s%s\n", newpfx, err_info->type,
+		       error_type,
+		       (err_info->type & ~CPER_ARM_ERR_TYPE_MASK) ? " with reserved bit(s)" : "");
+
 		if (err_info->validation_bits & CPER_ARM_INFO_VALID_ERR_INFO) {
 			printk("%serror_info: 0x%016llx\n", newpfx,
 			       err_info->error_info);

include/linux/cper.h

···
 #define CPER_ARM_INFO_FLAGS_PROPAGATED		BIT(2)
 #define CPER_ARM_INFO_FLAGS_OVERFLOW		BIT(3)
 
-#define CPER_ARM_CACHE_ERROR			0
-#define CPER_ARM_TLB_ERROR			1
-#define CPER_ARM_BUS_ERROR			2
-#define CPER_ARM_VENDOR_ERROR			3
-#define CPER_ARM_MAX_TYPE			CPER_ARM_VENDOR_ERROR
+#define CPER_ARM_ERR_TYPE_MASK			GENMASK(4,1)
+#define CPER_ARM_CACHE_ERROR			BIT(1)
+#define CPER_ARM_TLB_ERROR			BIT(2)
+#define CPER_ARM_BUS_ERROR			BIT(3)
+#define CPER_ARM_VENDOR_ERROR			BIT(4)
 
 #define CPER_ARM_ERR_VALID_TRANSACTION_TYPE	BIT(0)
 #define CPER_ARM_ERR_VALID_OPERATION_TYPE	BIT(1)