1 files changed, 20 insertions, 8 deletions

diff --git a/arch/s390/kernel/smp.c b/arch/s390/kernel/smp.c
index e299892440b6..58c8afa3da65 100644
--- a/arch/s390/kernel/smp.c
+++ b/arch/s390/kernel/smp.c
@@ -30,6 +30,7 @@
 #include <linux/delay.h>
 #include <linux/interrupt.h>
 #include <linux/irqflags.h>
+#include <linux/irq_work.h>
 #include <linux/cpu.h>
 #include <linux/slab.h>
 #include <linux/sched/hotplug.h>
@@ -62,6 +63,7 @@ enum {
 	ec_call_function_single,
 	ec_stop_cpu,
 	ec_mcck_pending,
+	ec_irq_work,
 };
 
 enum {
@@ -434,10 +436,12 @@ void notrace smp_yield_cpu(int cpu)
  */
 void notrace smp_emergency_stop(void)
 {
-	cpumask_t cpumask;
+	static arch_spinlock_t lock = __ARCH_SPIN_LOCK_UNLOCKED;
+	static cpumask_t cpumask;
 	u64 end;
 	int cpu;
 
+	arch_spin_lock(&lock);
 	cpumask_copy(&cpumask, cpu_online_mask);
 	cpumask_clear_cpu(smp_processor_id(), &cpumask);
 
@@ -458,6 +462,7 @@ void notrace smp_emergency_stop(void)
 			break;
 		cpu_relax();
 	}
+	arch_spin_unlock(&lock);
 }
 NOKPROBE_SYMBOL(smp_emergency_stop);
 
@@ -505,6 +510,8 @@ static void smp_handle_ext_call(void)
 		generic_smp_call_function_single_interrupt();
 	if (test_bit(ec_mcck_pending, &bits))
 		__s390_handle_mcck();
+	if (test_bit(ec_irq_work, &bits))
+		irq_work_run();
 }
 
 static void do_ext_call_interrupt(struct ext_code ext_code,
@@ -537,6 +544,13 @@ void smp_send_reschedule(int cpu)
 	pcpu_ec_call(pcpu_devices + cpu, ec_schedule);
 }
 
+#ifdef CONFIG_IRQ_WORK
+void arch_irq_work_raise(void)
+{
+	pcpu_ec_call(pcpu_devices + smp_processor_id(), ec_irq_work);
+}
+#endif
+
 /*
  * parameter area for the set/clear control bit callbacks
  */
@@ -775,11 +789,13 @@ static int smp_add_core(struct sclp_core_entry *core, cpumask_t *avail,
 static int __smp_rescan_cpus(struct sclp_core_info *info, bool early)
 {
 	struct sclp_core_entry *core;
-	cpumask_t avail;
+	static cpumask_t avail;
 	bool configured;
 	u16 core_id;
 	int nr, i;
 
+	get_online_cpus();
+	mutex_lock(&smp_cpu_state_mutex);
 	nr = 0;
 	cpumask_xor(&avail, cpu_possible_mask, cpu_present_mask);
 	/*
@@ -800,6 +816,8 @@ static int __smp_rescan_cpus(struct sclp_core_info *info, bool early)
 		configured = i < info->configured;
 		nr += smp_add_core(&info->core[i], &avail, configured, early);
 	}
+	mutex_unlock(&smp_cpu_state_mutex);
+	put_online_cpus();
 	return nr;
 }
 
@@ -847,9 +865,7 @@ void __init smp_detect_cpus(void)
 	pr_info("%d configured CPUs, %d standby CPUs\n", c_cpus, s_cpus);
 
 	/* Add CPUs present at boot */
-	get_online_cpus();
 	__smp_rescan_cpus(info, true);
-	put_online_cpus();
 	memblock_free_early((unsigned long)info, sizeof(*info));
 }
 
@@ -1178,11 +1194,7 @@ int __ref smp_rescan_cpus(void)
 	if (!info)
 		return -ENOMEM;
 	smp_get_core_info(info, 0);
-	get_online_cpus();
-	mutex_lock(&smp_cpu_state_mutex);
 	nr = __smp_rescan_cpus(info, false);
-	mutex_unlock(&smp_cpu_state_mutex);
-	put_online_cpus();
 	kfree(info);
 	if (nr)
 		topology_schedule_update();