Commit af7aa046 authored by Qais Yousef's avatar Qais Yousef Committed by Thomas Gleixner
Browse files

x86/smp: Replace cpu_up/down() with add/remove_cpu() 



The core device API performs extra housekeeping bits that are missing
from directly calling cpu_up/down().

See commit a6717c01 ("powerpc/rtas: use device model APIs and
serialization during LPM") for an example description of what might go
wrong.

This also prepares to make cpu_up/down() a private interface of the CPU
subsystem.

Signed-off-by: default avatarQais Yousef <qais.yousef@arm.com>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20200323135110.30522-10-qais.yousef@arm.com
parent e646ac5b

arch/x86/kernel/topology.c

+6 −16
Original line number Diff line number Diff line
@@ -59,39 +59,29 @@ __setup("cpu0_hotplug", enable_cpu0_hotplug); 
 */

int _debug_hotplug_cpu(int cpu, int action)

{

	struct device *dev = get_cpu_device(cpu);

	int ret;



	if (!cpu_is_hotpluggable(cpu))

		return -EINVAL;



	lock_device_hotplug();



	switch (action) {

	case 0:

		ret = cpu_down(cpu);

		if (!ret) {

		ret = remove_cpu(cpu);

		if (!ret)

			pr_info("DEBUG_HOTPLUG_CPU0: CPU %u is now offline\n", cpu);

			dev->offline = true;

			kobject_uevent(&dev->kobj, KOBJ_OFFLINE);

		} else

		else

			pr_debug("Can't offline CPU%d.\n", cpu);

		break;

	case 1:

		ret = cpu_up(cpu);

		if (!ret) {

			dev->offline = false;

			kobject_uevent(&dev->kobj, KOBJ_ONLINE);

		} else {

		ret = add_cpu(cpu);

		if (ret)

			pr_debug("Can't online CPU%d.\n", cpu);

		}



		break;

	default:

		ret = -EINVAL;

	}



	unlock_device_hotplug();



	return ret;

}

arch/x86/mm/mmio-mod.c

+2 −2
Original line number Diff line number Diff line
@@ -386,7 +386,7 @@ static void enter_uniprocessor(void) 
	put_online_cpus();



	for_each_cpu(cpu, downed_cpus) {

		err = cpu_down(cpu);

		err = remove_cpu(cpu);

		if (!err)

			pr_info("CPU%d is down.\n", cpu);

		else
@@ -406,7 +406,7 @@ static void leave_uniprocessor(void) 
		return;

	pr_notice("Re-enabling CPUs...\n");

	for_each_cpu(cpu, downed_cpus) {

		err = cpu_up(cpu);

		err = add_cpu(cpu);

		if (!err)

			pr_info("enabled CPU%d.\n", cpu);

		else

arch/x86/xen/smp.c

+1 −1
Original line number Diff line number Diff line
@@ -132,7 +132,7 @@ void __init xen_smp_cpus_done(unsigned int max_cpus) 
		if (xen_vcpu_nr(cpu) < MAX_VIRT_CPUS)

			continue;



		rc = cpu_down(cpu);

		rc = remove_cpu(cpu);



		if (rc == 0) {

			/*

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