6.12-stable review patch. If anyone has any objections, please let me know.
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From: Heiko Carstens hca@linux.ibm.com
[ Upstream commit 07a75d08cfa1b883a6e1256666e5f0617ee99231 ]
In case SCLP CPU detection does not work a fallback mechanism using SIGP is in place. Since a cleanup this does not work correctly anymore: new CPUs are only considered if their type matches the boot CPU.
Before the cleanup the information if a CPU type should be considered was also part of a structure generated by the fallback mechanism and indicated that a CPU type should not be considered when adding CPUs.
Since the rework a global SCLP state is used instead. If the global SCLP state indicates that the CPU type should be considered and the fallback mechanism is used, there may be a mismatch with CPU types if CPUs are added. This can lead to a system with only a single CPU even tough there are many more CPUs.
Address this by simply copying the boot cpu type into the generated data structure from the fallback mechanism.
Reported-by: Alexander Egorenkov egorenar@linux.ibm.com Fixes: d08d94306e90 ("s390/smp: cleanup core vs. cpu in the SCLP interface") Reviewed-by: Mete Durlu meted@linux.ibm.com Signed-off-by: Heiko Carstens hca@linux.ibm.com Signed-off-by: Sasha Levin sashal@kernel.org --- arch/s390/kernel/smp.c | 1 + 1 file changed, 1 insertion(+)
diff --git a/arch/s390/kernel/smp.c b/arch/s390/kernel/smp.c index 4df56fdb24880..b976f603dddcd 100644 --- a/arch/s390/kernel/smp.c +++ b/arch/s390/kernel/smp.c @@ -710,6 +710,7 @@ static void __ref smp_get_core_info(struct sclp_core_info *info, int early) continue; info->core[info->configured].core_id = address >> smp_cpu_mt_shift; + info->core[info->configured].type = boot_core_type; info->configured++; } info->combined = info->configured;