diff --git a/arch/powerpc/kexec/core_64.c b/arch/powerpc/kexec/core_64.c index 222aa326dace..825ab8a88f18 100644 --- a/arch/powerpc/kexec/core_64.c +++ b/arch/powerpc/kexec/core_64.c @@ -202,6 +202,23 @@ static void kexec_prepare_cpus_wait(int wait_state) mb(); } + +/* + * The add_cpu() call in wake_offline_cpus() can fail as cpu_bootable() + * returns false for CPUs that fail the cpu_smt_thread_allowed() check + * or non primary threads if SMT is disabled. Re-enable SMT and set the + * number of SMT threads to threads per core. + */ +static void kexec_smt_reenable(void) +{ +#if defined(CONFIG_SMP) && defined(CONFIG_HOTPLUG_SMT) + lock_device_hotplug(); + cpu_smt_num_threads = threads_per_core; + cpu_smt_control = CPU_SMT_ENABLED; + unlock_device_hotplug(); +#endif +} + /* * We need to make sure each present CPU is online. The next kernel will scan * the device tree and assume primary threads are online and query secondary @@ -216,6 +233,8 @@ static void wake_offline_cpus(void) { int cpu = 0; + kexec_smt_reenable(); + for_each_present_cpu(cpu) { if (!cpu_online(cpu)) { printk(KERN_INFO "kexec: Waking offline cpu %d.\n",