| From 4646cd6b09e2b5ceb1a9577e5e03316608ae587d Mon Sep 17 00:00:00 2001 |
| From: Arnd Bergmann <arnd@arndb.de> |
| Date: Tue, 10 Dec 2019 20:56:04 +0100 |
| Subject: [PATCH] cpu/SMT: Fix x86 link error without CONFIG_SYSFS |
| |
| commit dc8d37ed304eeeea47e65fb9edc1c6c8b0093386 upstream. |
| |
| 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: ec527c318036 ("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 |
| Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> |
| |
| diff --git a/kernel/cpu.c b/kernel/cpu.c |
| index 44fe5c7cfc07..4daebe385aac 100644 |
| --- a/kernel/cpu.c |
| +++ b/kernel/cpu.c |
| @@ -1892,6 +1892,78 @@ 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) |
| @@ -2046,77 +2118,6 @@ 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) |
| -- |
| 2.7.4 |
| |