[tip: ras/urgent] x86/mce/amd: Add default names for MCA banks and blocks

["tip-bot2 for Yazen Ghannam" <tip-bot2@linutronix.de>]

The following commit has been merged into the ras/urgent branch of tip:

Commit-ID:     d66e1e90b16055d2f0ee76e5384e3f119c3c2773
Gitweb:        https://git.kernel.org/tip/d66e1e90b16055d2f0ee76e5384e3f119c3c2773
Author:        Yazen Ghannam <yazen.ghannam@amd.com>
AuthorDate:    Tue, 24 Jun 2025 14:15:58 
Committer:     Borislav Petkov (AMD) <bp@alien8.de>
CommitterDate: Fri, 27 Jun 2025 13:13:36 +02:00

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: 87a6d4091bd7 ("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
---
 arch/x86/kernel/cpu/mce/amd.c | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

diff --git a/arch/x86/kernel/cpu/mce/amd.c b/arch/x86/kernel/cpu/mce/amd.c
index 9d852c3..6820ebc 100644
--- a/arch/x86/kernel/cpu/mce/amd.c
+++ b/arch/x86/kernel/cpu/mce/amd.c
@@ -1113,13 +1113,20 @@ 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)