From: Sven Schnelle Date: Tue, 8 Dec 2020 06:35:21 +0000 (+0100) Subject: s390/smp: perform initial CPU reset also for SMT siblings X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=b5e438ebd7e808d1d2435159ac4742e01a94b8da;p=linux.git s390/smp: perform initial CPU reset also for SMT siblings Not resetting the SMT siblings might leave them in unpredictable state. One of the observed problems was that the CPU timer wasn't reset and therefore large system time values where accounted during CPU bringup. Cc: # 4.0 Fixes: 10ad34bc76dfb ("s390: add SMT support") Reviewed-by: Heiko Carstens Signed-off-by: Sven Schnelle Signed-off-by: Heiko Carstens --- diff --git a/arch/s390/kernel/smp.c b/arch/s390/kernel/smp.c index 647226e50c80a..27c7630141148 100644 --- a/arch/s390/kernel/smp.c +++ b/arch/s390/kernel/smp.c @@ -890,24 +890,12 @@ static void __no_sanitize_address smp_start_secondary(void *cpuvoid) /* Upping and downing of CPUs */ int __cpu_up(unsigned int cpu, struct task_struct *tidle) { - struct pcpu *pcpu; - int base, i, rc; + struct pcpu *pcpu = pcpu_devices + cpu; + int rc; - pcpu = pcpu_devices + cpu; if (pcpu->state != CPU_STATE_CONFIGURED) return -EIO; - base = smp_get_base_cpu(cpu); - for (i = 0; i <= smp_cpu_mtid; i++) { - if (base + i < nr_cpu_ids) - if (cpu_online(base + i)) - break; - } - /* - * If this is the first CPU of the core to get online - * do an initial CPU reset. - */ - if (i > smp_cpu_mtid && - pcpu_sigp_retry(pcpu_devices + base, SIGP_INITIAL_CPU_RESET, 0) != + if (pcpu_sigp_retry(pcpu, SIGP_INITIAL_CPU_RESET, 0) != SIGP_CC_ORDER_CODE_ACCEPTED) return -EIO;