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

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

See commit a6717c01dd ("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: Qais Yousef <qais.yousef@arm.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20200323135110.30522-10-qais.yousef@arm.com
This commit is contained in:
Qais Yousef 2020-03-23 13:51:02 +00:00 committed by Thomas Gleixner
parent e646ac5bb8
commit af7aa04683
3 changed files with 9 additions and 19 deletions
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22
arch/x86/kernel/topology.c
View file

@ -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;
}

4
arch/x86/mm/mmio-mod.c
View file

@ -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

2
arch/x86/xen/smp.c
View file

@ -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) {
/*