Merge tag 'smp-core-2020-03-30' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

torvalds · torvalds · commit 992a1a3b45b5 · 2020-03-30T18:06:39.000-07:00
Pull core SMP updates from Thomas Gleixner:
 "CPU (hotplug) updates:

   - Support for locked CSD objects in smp_call_function_single_async()
     which allows to simplify callsites in the scheduler core and MIPS

   - Treewide consolidation of CPU hotplug functions which ensures the
     consistency between the sysfs interface and kernel state. The low
     level functions cpu_up/down() are now confined to the core code and
     not longer accessible from random code"

* tag 'smp-core-2020-03-30' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (22 commits)
  cpu/hotplug: Ignore pm_wakeup_pending() for disable_nonboot_cpus()
  cpu/hotplug: Hide cpu_up/down()
  cpu/hotplug: Move bringup of secondary CPUs out of smp_init()
  torture: Replace cpu_up/down() with add/remove_cpu()
  firmware: psci: Replace cpu_up/down() with add/remove_cpu()
  xen/cpuhotplug: Replace cpu_up/down() with device_online/offline()
  parisc: Replace cpu_up/down() with add/remove_cpu()
  sparc: Replace cpu_up/down() with add/remove_cpu()
  powerpc: Replace cpu_up/down() with add/remove_cpu()
  x86/smp: Replace cpu_up/down() with add/remove_cpu()
  arm64: hibernate: Use bringup_hibernate_cpu()
  cpu/hotplug: Provide bringup_hibernate_cpu()
  arm64: Use reboot_cpu instead of hardconding it to 0
  arm64: Don't use disable_nonboot_cpus()
  ARM: Use reboot_cpu instead of hardcoding it to 0
  ARM: Don't use disable_nonboot_cpus()
  ia64: Replace cpu_down() with smp_shutdown_nonboot_cpus()
  cpu/hotplug: Create a new function to shutdown nonboot cpus
  cpu/hotplug: Add new {add,remove}_cpu() functions
  sched/core: Remove rq.hrtick_csd_pending
  ...
diff --git a/arch/arm/kernel/reboot.c b/arch/arm/kernel/reboot.c
@@ -88,11 +88,11 @@ void soft_restart(unsigned long addr)
  * to execute e.g. a RAM-based pin loop is not sufficient. This allows the
  * kexec'd kernel to use any and all RAM as it sees fit, without having to
  * avoid any code or data used by any SW CPU pin loop. The CPU hotplug
- * functionality embodied in disable_nonboot_cpus() to achieve this.
+ * functionality embodied in smp_shutdown_nonboot_cpus() to achieve this.
  */
 void machine_shutdown(void)
 {
-	disable_nonboot_cpus();
+	smp_shutdown_nonboot_cpus(reboot_cpu);
 }
 
 /*
diff --git a/arch/arm64/kernel/hibernate.c b/arch/arm64/kernel/hibernate.c
@@ -166,14 +166,11 @@ int arch_hibernation_header_restore(void *addr)
 		sleep_cpu = -EINVAL;
 		return -EINVAL;
 	}
-	if (!cpu_online(sleep_cpu)) {
-		pr_info("Hibernated on a CPU that is offline! Bringing CPU up.\n");
-		ret = cpu_up(sleep_cpu);
-		if (ret) {
-			pr_err("Failed to bring hibernate-CPU up!\n");
-			sleep_cpu = -EINVAL;
-			return ret;
-		}
+
+	ret = bringup_hibernate_cpu(sleep_cpu);
+	if (ret) {
+		sleep_cpu = -EINVAL;
+		return ret;
 	}
 
 	resume_hdr = *hdr;
diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c
@@ -141,11 +141,11 @@ void arch_cpu_idle_dead(void)
  * to execute e.g. a RAM-based pin loop is not sufficient. This allows the
  * kexec'd kernel to use any and all RAM as it sees fit, without having to
  * avoid any code or data used by any SW CPU pin loop. The CPU hotplug
- * functionality embodied in disable_nonboot_cpus() to achieve this.
+ * functionality embodied in smpt_shutdown_nonboot_cpus() to achieve this.
  */
 void machine_shutdown(void)
 {
-	disable_nonboot_cpus();
+	smp_shutdown_nonboot_cpus(reboot_cpu);
 }
 
 /*
diff --git a/arch/ia64/kernel/process.c b/arch/ia64/kernel/process.c
@@ -646,14 +646,8 @@ cpu_halt (void)
 
 void machine_shutdown(void)
 {
-#ifdef CONFIG_HOTPLUG_CPU
-	int cpu;
+	smp_shutdown_nonboot_cpus(reboot_cpu);
 
-	for_each_online_cpu(cpu) {
-		if (cpu != smp_processor_id())
-			cpu_down(cpu);
-	}
-#endif
 #ifdef CONFIG_KEXEC
 	kexec_disable_iosapic();
 #endif
diff --git a/arch/mips/kernel/smp.c b/arch/mips/kernel/smp.c
@@ -696,29 +696,22 @@ EXPORT_SYMBOL(flush_tlb_one);
 
 #ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST
 
-static DEFINE_PER_CPU(atomic_t, tick_broadcast_count);
 static DEFINE_PER_CPU(call_single_data_t, tick_broadcast_csd);
 
 void tick_broadcast(const struct cpumask *mask)
 {
-	atomic_t *count;
 	call_single_data_t *csd;
 	int cpu;
 
 	for_each_cpu(cpu, mask) {
-		count = &per_cpu(tick_broadcast_count, cpu);
 		csd = &per_cpu(tick_broadcast_csd, cpu);
-
-		if (atomic_inc_return(count) == 1)
-			smp_call_function_single_async(cpu, csd);
+		smp_call_function_single_async(cpu, csd);
 	}
 }
 
 static void tick_broadcast_callee(void *info)
 {
-	int cpu = smp_processor_id();
 	tick_receive_broadcast();
-	atomic_set(&per_cpu(tick_broadcast_count, cpu), 0);
 }
 
 static int __init tick_broadcast_init(void)
diff --git a/arch/parisc/kernel/processor.c b/arch/parisc/kernel/processor.c
@@ -212,7 +212,7 @@ static int __init processor_probe(struct parisc_device *dev)
 #ifdef CONFIG_SMP
 	if (cpuid) {
 		set_cpu_present(cpuid, true);
-		cpu_up(cpuid);
+		add_cpu(cpuid);
 	}
 #endif
 
diff --git a/arch/powerpc/kexec/core_64.c b/arch/powerpc/kexec/core_64.c
@@ -212,7 +212,7 @@ static void wake_offline_cpus(void)
 		if (!cpu_online(cpu)) {
 			printk(KERN_INFO "kexec: Waking offline cpu %d.\n",
 			       cpu);
-			WARN_ON(cpu_up(cpu));
+			WARN_ON(add_cpu(cpu));
 		}
 	}
 }
diff --git a/arch/sparc/kernel/ds.c b/arch/sparc/kernel/ds.c
@@ -555,7 +555,7 @@ static int dr_cpu_configure(struct ds_info *dp, struct ds_cap_state *cp,
 
 		printk(KERN_INFO "ds-%llu: Starting cpu %d...\n",
 		       dp->id, cpu);
-		err = cpu_up(cpu);
+		err = add_cpu(cpu);
 		if (err) {
 			__u32 res = DR_CPU_RES_FAILURE;
 			__u32 stat = DR_CPU_STAT_UNCONFIGURED;
@@ -611,7 +611,7 @@ static int dr_cpu_unconfigure(struct ds_info *dp,
 
 		printk(KERN_INFO "ds-%llu: Shutting down cpu %d...\n",
 		       dp->id, cpu);
-		err = cpu_down(cpu);
+		err = remove_cpu(cpu);
 		if (err)
 			dr_cpu_mark(resp, cpu, ncpus,
 				    DR_CPU_RES_FAILURE,
diff --git a/arch/x86/kernel/topology.c b/arch/x86/kernel/topology.c
@@ -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;
 }
 
diff --git a/arch/x86/mm/mmio-mod.c b/arch/x86/mm/mmio-mod.c
@@ -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
diff --git a/arch/x86/xen/smp.c b/arch/x86/xen/smp.c
@@ -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) {
 			/*
diff --git a/drivers/base/cpu.c b/drivers/base/cpu.c
@@ -55,7 +55,7 @@ static int cpu_subsys_online(struct device *dev)
 	if (from_nid == NUMA_NO_NODE)
 		return -ENODEV;
 
-	ret = cpu_up(cpuid);
+	ret = cpu_device_up(dev);
 	/*
 	 * When hot adding memory to memoryless node and enabling a cpu
 	 * on the node, node number of the cpu may internally change.
@@ -69,7 +69,7 @@ static int cpu_subsys_online(struct device *dev)
 
 static int cpu_subsys_offline(struct device *dev)
 {
-	return cpu_down(dev->id);
+	return cpu_device_down(dev);
 }
 
 void unregister_cpu(struct cpu *cpu)
diff --git a/drivers/firmware/psci/psci_checker.c b/drivers/firmware/psci/psci_checker.c
@@ -84,7 +84,7 @@ static unsigned int down_and_up_cpus(const struct cpumask *cpus,
 
 	/* Try to power down all CPUs in the mask. */
 	for_each_cpu(cpu, cpus) {
-		int ret = cpu_down(cpu);
+		int ret = remove_cpu(cpu);
 
 		/*
 		 * cpu_down() checks the number of online CPUs before the TOS
@@ -116,7 +116,7 @@ static unsigned int down_and_up_cpus(const struct cpumask *cpus,
 
 	/* Try to power up all the CPUs that have been offlined. */
 	for_each_cpu(cpu, offlined_cpus) {
-		int ret = cpu_up(cpu);
+		int ret = add_cpu(cpu);
 
 		if (ret != 0) {
 			pr_err("Error occurred (%d) while trying "
diff --git a/drivers/xen/cpu_hotplug.c b/drivers/xen/cpu_hotplug.c
@@ -94,7 +94,7 @@ static int setup_cpu_watcher(struct notifier_block *notifier,
 
 	for_each_possible_cpu(cpu) {
 		if (vcpu_online(cpu) == 0) {
-			(void)cpu_down(cpu);
+			device_offline(get_cpu_device(cpu));
 			set_cpu_present(cpu, false);
 		}
 	}
diff --git a/include/linux/cpu.h b/include/linux/cpu.h
@@ -88,10 +88,13 @@ extern ssize_t arch_cpu_release(const char *, size_t);
 
 #ifdef CONFIG_SMP
 extern bool cpuhp_tasks_frozen;
-int cpu_up(unsigned int cpu);
+int add_cpu(unsigned int cpu);
+int cpu_device_up(struct device *dev);
 void notify_cpu_starting(unsigned int cpu);
 extern void cpu_maps_update_begin(void);
 extern void cpu_maps_update_done(void);
+int bringup_hibernate_cpu(unsigned int sleep_cpu);
+void bringup_nonboot_cpus(unsigned int setup_max_cpus);
 
 #else	/* CONFIG_SMP */
 #define cpuhp_tasks_frozen	0
@@ -117,7 +120,9 @@ extern void lockdep_assert_cpus_held(void);
 extern void cpu_hotplug_disable(void);
 extern void cpu_hotplug_enable(void);
 void clear_tasks_mm_cpumask(int cpu);
-int cpu_down(unsigned int cpu);
+int remove_cpu(unsigned int cpu);
+int cpu_device_down(struct device *dev);
+extern void smp_shutdown_nonboot_cpus(unsigned int primary_cpu);
 
 #else /* CONFIG_HOTPLUG_CPU */
 
@@ -129,6 +134,7 @@ static inline int  cpus_read_trylock(void) { return true; }
 static inline void lockdep_assert_cpus_held(void) { }
 static inline void cpu_hotplug_disable(void) { }
 static inline void cpu_hotplug_enable(void) { }
+static inline void smp_shutdown_nonboot_cpus(unsigned int primary_cpu) { }
 #endif	/* !CONFIG_HOTPLUG_CPU */
 
 /* Wrappers which go away once all code is converted */
@@ -138,12 +144,18 @@ static inline void get_online_cpus(void) { cpus_read_lock(); }
 static inline void put_online_cpus(void) { cpus_read_unlock(); }
 
 #ifdef CONFIG_PM_SLEEP_SMP
-extern int freeze_secondary_cpus(int primary);
+int __freeze_secondary_cpus(int primary, bool suspend);
+static inline int freeze_secondary_cpus(int primary)
+{
+	return __freeze_secondary_cpus(primary, true);
+}
+
 static inline int disable_nonboot_cpus(void)
 {
-	return freeze_secondary_cpus(0);
+	return __freeze_secondary_cpus(0, false);
 }
-extern void enable_nonboot_cpus(void);
+
+void enable_nonboot_cpus(void);
 
 static inline int suspend_disable_secondary_cpus(void)
 {
diff --git a/kernel/cpu.c b/kernel/cpu.c
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
diff --git a/kernel/smp.c b/kernel/smp.c
diff --git a/kernel/torture.c b/kernel/torture.c

Original file line number	Diff line number	Diff line change
`@@ -88,11 +88,11 @@ void soft_restart(unsigned long addr)`
`88`	`88`	`* to execute e.g. a RAM-based pin loop is not sufficient. This allows the`
`89`	`89`	`* kexec'd kernel to use any and all RAM as it sees fit, without having to`
`90`	`90`	`* avoid any code or data used by any SW CPU pin loop. The CPU hotplug`
`91`		`- * functionality embodied in disable_nonboot_cpus() to achieve this.`
	`91`	`+ * functionality embodied in smp_shutdown_nonboot_cpus() to achieve this.`
`92`	`92`	`*/`
`93`	`93`	`void machine_shutdown(void)`
`94`	`94`	`{`
`95`		`- disable_nonboot_cpus();`
	`95`	`+ smp_shutdown_nonboot_cpus(reboot_cpu);`
`96`	`96`	`}`
`97`	`97`
`98`	`98`	`/*`
Original file line number	Diff line number	Diff line change
`@@ -141,11 +141,11 @@ void arch_cpu_idle_dead(void)`
`141`	`141`	`* to execute e.g. a RAM-based pin loop is not sufficient. This allows the`
`142`	`142`	`* kexec'd kernel to use any and all RAM as it sees fit, without having to`
`143`	`143`	`* avoid any code or data used by any SW CPU pin loop. The CPU hotplug`
`144`		`- * functionality embodied in disable_nonboot_cpus() to achieve this.`
	`144`	`+ * functionality embodied in smpt_shutdown_nonboot_cpus() to achieve this.`
`145`	`145`	`*/`
`146`	`146`	`void machine_shutdown(void)`
`147`	`147`	`{`
`148`		`- disable_nonboot_cpus();`
	`148`	`+ smp_shutdown_nonboot_cpus(reboot_cpu);`
`149`	`149`	`}`
`150`	`150`
`151`	`151`	`/*`
Original file line number	Diff line number	Diff line change
`@@ -696,29 +696,22 @@ EXPORT_SYMBOL(flush_tlb_one);`
`696`	`696`
`697`	`697`	`#ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST`
`698`	`698`
`699`		`-static DEFINE_PER_CPU(atomic_t, tick_broadcast_count);`
`700`	`699`	`static DEFINE_PER_CPU(call_single_data_t, tick_broadcast_csd);`
`701`	`700`
`702`	`701`	`void tick_broadcast(const struct cpumask *mask)`
`703`	`702`	`{`
`704`		`- atomic_t *count;`
`705`	`703`	`call_single_data_t *csd;`
`706`	`704`	`int cpu;`
`707`	`705`
`708`	`706`	`for_each_cpu(cpu, mask) {`
`709`		`- count = &per_cpu(tick_broadcast_count, cpu);`
`710`	`707`	`csd = &per_cpu(tick_broadcast_csd, cpu);`
`711`		`-`
`712`		`- if (atomic_inc_return(count) == 1)`
`713`		`- smp_call_function_single_async(cpu, csd);`
	`708`	`+ smp_call_function_single_async(cpu, csd);`
`714`	`709`	`}`
`715`	`710`	`}`
`716`	`711`
`717`	`712`	`static void tick_broadcast_callee(void *info)`
`718`	`713`	`{`
`719`		`- int cpu = smp_processor_id();`
`720`	`714`	`tick_receive_broadcast();`
`721`		`- atomic_set(&per_cpu(tick_broadcast_count, cpu), 0);`
`722`	`715`	`}`
`723`	`716`
`724`	`717`	`static int __init tick_broadcast_init(void)`
Original file line number	Diff line number	Diff line change
`@@ -212,7 +212,7 @@ static int __init processor_probe(struct parisc_device *dev)`
`212`	`212`	`#ifdef CONFIG_SMP`
`213`	`213`	`if (cpuid) {`
`214`	`214`	`set_cpu_present(cpuid, true);`
`215`		`- cpu_up(cpuid);`
	`215`	`+ add_cpu(cpuid);`
`216`	`216`	`}`
`217`	`217`	`#endif`
`218`	`218`
Original file line number	Diff line number	Diff line change
`@@ -212,7 +212,7 @@ static void wake_offline_cpus(void)`
`212`	`212`	`if (!cpu_online(cpu)) {`
`213`	`213`	`printk(KERN_INFO "kexec: Waking offline cpu %d.\n",`
`214`	`214`	`cpu);`
`215`		`- WARN_ON(cpu_up(cpu));`
	`215`	`+ WARN_ON(add_cpu(cpu));`
`216`	`216`	`}`
`217`	`217`	`}`
`218`	`218`	`}`