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cpu/SMT: Fix x86 link error without CONFIG_SYSFS 

When CONFIG_SYSFS is disabled, but CONFIG_HOTPLUG_SMT is enabled,
the kernel fails to link:

arch/x86/power/cpu.o: In function `hibernate_resume_nonboot_cpu_disable':
(.text+0x38d): undefined reference to `cpuhp_smt_enable'
arch/x86/power/hibernate.o: In function `arch_resume_nosmt':
hibernate.c:(.text+0x291): undefined reference to `cpuhp_smt_enable'
hibernate.c:(.text+0x29c): undefined reference to `cpuhp_smt_disable'

Move the exported functions out of the #ifdef section into its
own with the correct conditions.

The patch that caused this is marked for stable backports, so
this one may need to be backported as well.

Fixes: ec527c3180 ("x86/power: Fix 'nosmt' vs hibernation triple fault during resume")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Jiri Kosina <jkosina@suse.cz>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20191210195614.786555-1-arnd@arndb.de
This commit is contained in:
Arnd Bergmann 2019-12-10 20:56:04 +01:00 committed by Thomas Gleixner
parent c79f46a282
commit dc8d37ed30
1 changed files with 72 additions and 71 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

143
kernel/cpu.c
View File

@ -1909,6 +1909,78 @@ void __cpuhp_remove_state(enum cpuhp_state state, bool invoke)
}
EXPORT_SYMBOL(__cpuhp_remove_state);
#ifdef CONFIG_HOTPLUG_SMT
static void cpuhp_offline_cpu_device(unsigned int cpu)
{
struct device *dev = get_cpu_device(cpu);
dev->offline = true;
/* Tell user space about the state change */
kobject_uevent(&dev->kobj, KOBJ_OFFLINE);
}
static void cpuhp_online_cpu_device(unsigned int cpu)
{
struct device *dev = get_cpu_device(cpu);
dev->offline = false;
/* Tell user space about the state change */
kobject_uevent(&dev->kobj, KOBJ_ONLINE);
}
int cpuhp_smt_disable(enum cpuhp_smt_control ctrlval)
{
int cpu, ret = 0;
cpu_maps_update_begin();
for_each_online_cpu(cpu) {
if (topology_is_primary_thread(cpu))
continue;
ret = cpu_down_maps_locked(cpu, CPUHP_OFFLINE);
if (ret)
break;
/*
* As this needs to hold the cpu maps lock it's impossible
* to call device_offline() because that ends up calling
* cpu_down() which takes cpu maps lock. cpu maps lock
* needs to be held as this might race against in kernel
* abusers of the hotplug machinery (thermal management).
*
* So nothing would update device:offline state. That would
* leave the sysfs entry stale and prevent onlining after
* smt control has been changed to 'off' again. This is
* called under the sysfs hotplug lock, so it is properly
* serialized against the regular offline usage.
*/
cpuhp_offline_cpu_device(cpu);
}
if (!ret)
cpu_smt_control = ctrlval;
cpu_maps_update_done();
return ret;
}
int cpuhp_smt_enable(void)
{
int cpu, ret = 0;
cpu_maps_update_begin();
cpu_smt_control = CPU_SMT_ENABLED;
for_each_present_cpu(cpu) {
/* Skip online CPUs and CPUs on offline nodes */
if (cpu_online(cpu) || !node_online(cpu_to_node(cpu)))
continue;
ret = _cpu_up(cpu, 0, CPUHP_ONLINE);
if (ret)
break;
/* See comment in cpuhp_smt_disable() */
cpuhp_online_cpu_device(cpu);
}
cpu_maps_update_done();
return ret;
}
#endif
#if defined(CONFIG_SYSFS) && defined(CONFIG_HOTPLUG_CPU)
static ssize_t show_cpuhp_state(struct device *dev,
struct device_attribute *attr, char *buf)
@ -2063,77 +2135,6 @@ static const struct attribute_group cpuhp_cpu_root_attr_group = {
#ifdef CONFIG_HOTPLUG_SMT
static void cpuhp_offline_cpu_device(unsigned int cpu)
{
struct device *dev = get_cpu_device(cpu);
dev->offline = true;
/* Tell user space about the state change */
kobject_uevent(&dev->kobj, KOBJ_OFFLINE);
}
static void cpuhp_online_cpu_device(unsigned int cpu)
{
struct device *dev = get_cpu_device(cpu);
dev->offline = false;
/* Tell user space about the state change */
kobject_uevent(&dev->kobj, KOBJ_ONLINE);
}
int cpuhp_smt_disable(enum cpuhp_smt_control ctrlval)
{
int cpu, ret = 0;
cpu_maps_update_begin();
for_each_online_cpu(cpu) {
if (topology_is_primary_thread(cpu))
continue;
ret = cpu_down_maps_locked(cpu, CPUHP_OFFLINE);
if (ret)
break;
/*
* As this needs to hold the cpu maps lock it's impossible
* to call device_offline() because that ends up calling
* cpu_down() which takes cpu maps lock. cpu maps lock
* needs to be held as this might race against in kernel
* abusers of the hotplug machinery (thermal management).
*
* So nothing would update device:offline state. That would
* leave the sysfs entry stale and prevent onlining after
* smt control has been changed to 'off' again. This is
* called under the sysfs hotplug lock, so it is properly
* serialized against the regular offline usage.
*/
cpuhp_offline_cpu_device(cpu);
}
if (!ret)
cpu_smt_control = ctrlval;
cpu_maps_update_done();
return ret;
}
int cpuhp_smt_enable(void)
{
int cpu, ret = 0;
cpu_maps_update_begin();
cpu_smt_control = CPU_SMT_ENABLED;
for_each_present_cpu(cpu) {
/* Skip online CPUs and CPUs on offline nodes */
if (cpu_online(cpu) || !node_online(cpu_to_node(cpu)))
continue;
ret = _cpu_up(cpu, 0, CPUHP_ONLINE);
if (ret)
break;
/* See comment in cpuhp_smt_disable() */
cpuhp_online_cpu_device(cpu);
}
cpu_maps_update_done();
return ret;
}
static ssize_t
__store_smt_control(struct device *dev, struct device_attribute *attr,
const char *buf, size_t count)