x86/mce/amd: Add default names for MCA banks and blocks

JIRA: https://issues.redhat.com/browse/RHEL-117597

commit d66e1e9
Author: Yazen Ghannam <yazen.ghannam@amd.com>
Date:   Tue Jun 24 14:15:58 2025 +0000

    x86/mce/amd: Add default names for MCA banks and blocks

    Ensure that sysfs init doesn't fail for new/unrecognized bank types or if
    a bank has additional blocks available.

    Most MCA banks have a single thresholding block, so the block takes the same
    name as the bank.

    Unified Memory Controllers (UMCs) are a special case where there are two
    blocks and each has a unique name.

    However, the microarchitecture allows for five blocks. Any new MCA bank types
    with more than one block will be missing names for the extra blocks. The MCE
    sysfs will fail to initialize in this case.

    Fixes: 87a6d40 ("x86/mce/AMD: Update sysfs bank names for SMCA systems")
    Signed-off-by: Yazen Ghannam <yazen.ghannam@amd.com>
    Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
    Cc: stable@vger.kernel.org
    Link: https://lore.kernel.org/20250624-wip-mca-updates-v4-3-236dd74f645f@amd.com

Signed-off-by: Steve Best <sbest@redhat.com>

Author: sfbest

arch/x86/kernel/cpu/mce/amd.c

@@ -1109,13 +1109,20 @@ static const char *get_name(unsigned int cpu, unsigned int bank, struct threshol
 	}
 
 	bank_type = smca_get_bank_type(cpu, bank);
-	if (bank_type >= N_SMCA_BANK_TYPES)
-		return NULL;
 
 	if (b && (bank_type == SMCA_UMC || bank_type == SMCA_UMC_V2)) {
 		if (b->block < ARRAY_SIZE(smca_umc_block_names))
 			return smca_umc_block_names[b->block];
-		return NULL;
+	}
+
+	if (b && b->block) {
+		snprintf(buf_mcatype, MAX_MCATYPE_NAME_LEN, "th_block_%u", b->block);
+		return buf_mcatype;
+	}
+
+	if (bank_type >= N_SMCA_BANK_TYPES) {
+		snprintf(buf_mcatype, MAX_MCATYPE_NAME_LEN, "th_bank_%u", bank);
+		return buf_mcatype;
 	}
 
 	if (per_cpu(smca_bank_counts, cpu)[bank_type] == 1)