| /* CPU control. |
| * (C) 2001, 2002, 2003, 2004 Rusty Russell |
| * |
| * This code is licenced under the GPL. |
| */ |
| #include <linux/proc_fs.h> |
| #include <linux/smp.h> |
| #include <linux/init.h> |
| #include <linux/notifier.h> |
| #include <linux/sched/signal.h> |
| #include <linux/sched/hotplug.h> |
| #include <linux/sched/task.h> |
| #include <linux/sched/smt.h> |
| #include <linux/unistd.h> |
| #include <linux/cpu.h> |
| #include <linux/oom.h> |
| #include <linux/rcupdate.h> |
| #include <linux/export.h> |
| #include <linux/bug.h> |
| #include <linux/kthread.h> |
| #include <linux/stop_machine.h> |
| #include <linux/mutex.h> |
| #include <linux/gfp.h> |
| #include <linux/suspend.h> |
| #include <linux/lockdep.h> |
| #include <linux/tick.h> |
| #include <linux/irq.h> |
| #include <linux/nmi.h> |
| #include <linux/smpboot.h> |
| #include <linux/relay.h> |
| #include <linux/slab.h> |
| #include <linux/percpu-rwsem.h> |
| |
| #include <trace/events/power.h> |
| #define CREATE_TRACE_POINTS |
| #include <trace/events/cpuhp.h> |
| |
| #include "smpboot.h" |
| |
| /** |
| * cpuhp_cpu_state - Per cpu hotplug state storage |
| * @state: The current cpu state |
| * @target: The target state |
| * @thread: Pointer to the hotplug thread |
| * @should_run: Thread should execute |
| * @rollback: Perform a rollback |
| * @single: Single callback invocation |
| * @bringup: Single callback bringup or teardown selector |
| * @cb_state: The state for a single callback (install/uninstall) |
| * @result: Result of the operation |
| * @done_up: Signal completion to the issuer of the task for cpu-up |
| * @done_down: Signal completion to the issuer of the task for cpu-down |
| */ |
| struct cpuhp_cpu_state { |
| enum cpuhp_state state; |
| enum cpuhp_state target; |
| enum cpuhp_state fail; |
| #ifdef CONFIG_SMP |
| struct task_struct *thread; |
| bool should_run; |
| bool rollback; |
| bool single; |
| bool bringup; |
| bool booted_once; |
| struct hlist_node *node; |
| struct hlist_node *last; |
| enum cpuhp_state cb_state; |
| int result; |
| struct completion done_up; |
| struct completion done_down; |
| #endif |
| }; |
| |
| static DEFINE_PER_CPU(struct cpuhp_cpu_state, cpuhp_state) = { |
| .fail = CPUHP_INVALID, |
| }; |
| |
| #if defined(CONFIG_LOCKDEP) && defined(CONFIG_SMP) |
| static struct lockdep_map cpuhp_state_up_map = |
| STATIC_LOCKDEP_MAP_INIT("cpuhp_state-up", &cpuhp_state_up_map); |
| static struct lockdep_map cpuhp_state_down_map = |
| STATIC_LOCKDEP_MAP_INIT("cpuhp_state-down", &cpuhp_state_down_map); |
| |
| |
| static void inline cpuhp_lock_acquire(bool bringup) |
| { |
| lock_map_acquire(bringup ? &cpuhp_state_up_map : &cpuhp_state_down_map); |
| } |
| |
| static void inline cpuhp_lock_release(bool bringup) |
| { |
| lock_map_release(bringup ? &cpuhp_state_up_map : &cpuhp_state_down_map); |
| } |
| #else |
| |
| static void inline cpuhp_lock_acquire(bool bringup) { } |
| static void inline cpuhp_lock_release(bool bringup) { } |
| |
| #endif |
| |
| /** |
| * cpuhp_step - Hotplug state machine step |
| * @name: Name of the step |
| * @startup: Startup function of the step |
| * @teardown: Teardown function of the step |
| * @skip_onerr: Do not invoke the functions on error rollback |
| * Will go away once the notifiers are gone |
| * @cant_stop: Bringup/teardown can't be stopped at this step |
| */ |
| struct cpuhp_step { |
| const char *name; |
| union { |
| int (*single)(unsigned int cpu); |
| int (*multi)(unsigned int cpu, |
| struct hlist_node *node); |
| } startup; |
| union { |
| int (*single)(unsigned int cpu); |
| int (*multi)(unsigned int cpu, |
| struct hlist_node *node); |
| } teardown; |
| struct hlist_head list; |
| bool skip_onerr; |
| bool cant_stop; |
| bool multi_instance; |
| }; |
| |
| static DEFINE_MUTEX(cpuhp_state_mutex); |
| static struct cpuhp_step cpuhp_bp_states[]; |
| static struct cpuhp_step cpuhp_ap_states[]; |
| |
| static bool cpuhp_is_ap_state(enum cpuhp_state state) |
| { |
| /* |
| * The extra check for CPUHP_TEARDOWN_CPU is only for documentation |
| * purposes as that state is handled explicitly in cpu_down. |
| */ |
| return state > CPUHP_BRINGUP_CPU && state != CPUHP_TEARDOWN_CPU; |
| } |
| |
| static struct cpuhp_step *cpuhp_get_step(enum cpuhp_state state) |
| { |
| struct cpuhp_step *sp; |
| |
| sp = cpuhp_is_ap_state(state) ? cpuhp_ap_states : cpuhp_bp_states; |
| return sp + state; |
| } |
| |
| /** |
| * cpuhp_invoke_callback _ Invoke the callbacks for a given state |
| * @cpu: The cpu for which the callback should be invoked |
| * @state: The state to do callbacks for |
| * @bringup: True if the bringup callback should be invoked |
| * @node: For multi-instance, do a single entry callback for install/remove |
| * @lastp: For multi-instance rollback, remember how far we got |
| * |
| * Called from cpu hotplug and from the state register machinery. |
| */ |
| static int cpuhp_invoke_callback(unsigned int cpu, enum cpuhp_state state, |
| bool bringup, struct hlist_node *node, |
| struct hlist_node **lastp) |
| { |
| struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); |
| struct cpuhp_step *step = cpuhp_get_step(state); |
| int (*cbm)(unsigned int cpu, struct hlist_node *node); |
| int (*cb)(unsigned int cpu); |
| int ret, cnt; |
| |
| if (st->fail == state) { |
| st->fail = CPUHP_INVALID; |
| |
| if (!(bringup ? step->startup.single : step->teardown.single)) |
| return 0; |
| |
| return -EAGAIN; |
| } |
| |
| if (!step->multi_instance) { |
| WARN_ON_ONCE(lastp && *lastp); |
| cb = bringup ? step->startup.single : step->teardown.single; |
| if (!cb) |
| return 0; |
| trace_cpuhp_enter(cpu, st->target, state, cb); |
| ret = cb(cpu); |
| trace_cpuhp_exit(cpu, st->state, state, ret); |
| return ret; |
| } |
| cbm = bringup ? step->startup.multi : step->teardown.multi; |
| if (!cbm) |
| return 0; |
| |
| /* Single invocation for instance add/remove */ |
| if (node) { |
| WARN_ON_ONCE(lastp && *lastp); |
| trace_cpuhp_multi_enter(cpu, st->target, state, cbm, node); |
| ret = cbm(cpu, node); |
| trace_cpuhp_exit(cpu, st->state, state, ret); |
| return ret; |
| } |
| |
| /* State transition. Invoke on all instances */ |
| cnt = 0; |
| hlist_for_each(node, &step->list) { |
| if (lastp && node == *lastp) |
| break; |
| |
| trace_cpuhp_multi_enter(cpu, st->target, state, cbm, node); |
| ret = cbm(cpu, node); |
| trace_cpuhp_exit(cpu, st->state, state, ret); |
| if (ret) { |
| if (!lastp) |
| goto err; |
| |
| *lastp = node; |
| return ret; |
| } |
| cnt++; |
| } |
| if (lastp) |
| *lastp = NULL; |
| return 0; |
| err: |
| /* Rollback the instances if one failed */ |
| cbm = !bringup ? step->startup.multi : step->teardown.multi; |
| if (!cbm) |
| return ret; |
| |
| hlist_for_each(node, &step->list) { |
| if (!cnt--) |
| break; |
| |
| trace_cpuhp_multi_enter(cpu, st->target, state, cbm, node); |
| ret = cbm(cpu, node); |
| trace_cpuhp_exit(cpu, st->state, state, ret); |
| /* |
| * Rollback must not fail, |
| */ |
| WARN_ON_ONCE(ret); |
| } |
| return ret; |
| } |
| |
| #ifdef CONFIG_SMP |
| static inline void wait_for_ap_thread(struct cpuhp_cpu_state *st, bool bringup) |
| { |
| struct completion *done = bringup ? &st->done_up : &st->done_down; |
| wait_for_completion(done); |
| } |
| |
| static inline void complete_ap_thread(struct cpuhp_cpu_state *st, bool bringup) |
| { |
| struct completion *done = bringup ? &st->done_up : &st->done_down; |
| complete(done); |
| } |
| |
| /* |
| * The former STARTING/DYING states, ran with IRQs disabled and must not fail. |
| */ |
| static bool cpuhp_is_atomic_state(enum cpuhp_state state) |
| { |
| return CPUHP_AP_IDLE_DEAD <= state && state < CPUHP_AP_ONLINE; |
| } |
| |
| /* Serializes the updates to cpu_online_mask, cpu_present_mask */ |
| static DEFINE_MUTEX(cpu_add_remove_lock); |
| bool cpuhp_tasks_frozen; |
| EXPORT_SYMBOL_GPL(cpuhp_tasks_frozen); |
| |
| /* |
| * The following two APIs (cpu_maps_update_begin/done) must be used when |
| * attempting to serialize the updates to cpu_online_mask & cpu_present_mask. |
| */ |
| void cpu_maps_update_begin(void) |
| { |
| mutex_lock(&cpu_add_remove_lock); |
| } |
| |
| void cpu_maps_update_done(void) |
| { |
| mutex_unlock(&cpu_add_remove_lock); |
| } |
| |
| /* |
| * If set, cpu_up and cpu_down will return -EBUSY and do nothing. |
| * Should always be manipulated under cpu_add_remove_lock |
| */ |
| static int cpu_hotplug_disabled; |
| |
| #ifdef CONFIG_HOTPLUG_CPU |
| |
| DEFINE_STATIC_PERCPU_RWSEM(cpu_hotplug_lock); |
| |
| void cpus_read_lock(void) |
| { |
| percpu_down_read(&cpu_hotplug_lock); |
| } |
| EXPORT_SYMBOL_GPL(cpus_read_lock); |
| |
| void cpus_read_unlock(void) |
| { |
| percpu_up_read(&cpu_hotplug_lock); |
| } |
| EXPORT_SYMBOL_GPL(cpus_read_unlock); |
| |
| void cpus_write_lock(void) |
| { |
| percpu_down_write(&cpu_hotplug_lock); |
| } |
| |
| void cpus_write_unlock(void) |
| { |
| percpu_up_write(&cpu_hotplug_lock); |
| } |
| |
| void lockdep_assert_cpus_held(void) |
| { |
| /* |
| * We can't have hotplug operations before userspace starts running, |
| * and some init codepaths will knowingly not take the hotplug lock. |
| * This is all valid, so mute lockdep until it makes sense to report |
| * unheld locks. |
| */ |
| if (system_state < SYSTEM_RUNNING) |
| return; |
| |
| percpu_rwsem_assert_held(&cpu_hotplug_lock); |
| } |
| |
| /* |
| * Wait for currently running CPU hotplug operations to complete (if any) and |
| * disable future CPU hotplug (from sysfs). The 'cpu_add_remove_lock' protects |
| * the 'cpu_hotplug_disabled' flag. The same lock is also acquired by the |
| * hotplug path before performing hotplug operations. So acquiring that lock |
| * guarantees mutual exclusion from any currently running hotplug operations. |
| */ |
| void cpu_hotplug_disable(void) |
| { |
| cpu_maps_update_begin(); |
| cpu_hotplug_disabled++; |
| cpu_maps_update_done(); |
| } |
| EXPORT_SYMBOL_GPL(cpu_hotplug_disable); |
| |
| static void __cpu_hotplug_enable(void) |
| { |
| if (WARN_ONCE(!cpu_hotplug_disabled, "Unbalanced cpu hotplug enable\n")) |
| return; |
| cpu_hotplug_disabled--; |
| } |
| |
| void cpu_hotplug_enable(void) |
| { |
| cpu_maps_update_begin(); |
| __cpu_hotplug_enable(); |
| cpu_maps_update_done(); |
| } |
| EXPORT_SYMBOL_GPL(cpu_hotplug_enable); |
| #endif /* CONFIG_HOTPLUG_CPU */ |
| |
| /* |
| * Architectures that need SMT-specific errata handling during SMT hotplug |
| * should override this. |
| */ |
| void __weak arch_smt_update(void) { } |
| |
| #ifdef CONFIG_HOTPLUG_SMT |
| enum cpuhp_smt_control cpu_smt_control __read_mostly = CPU_SMT_ENABLED; |
| |
| void __init cpu_smt_disable(bool force) |
| { |
| if (cpu_smt_control == CPU_SMT_FORCE_DISABLED || |
| cpu_smt_control == CPU_SMT_NOT_SUPPORTED) |
| return; |
| |
| if (force) { |
| pr_info("SMT: Force disabled\n"); |
| cpu_smt_control = CPU_SMT_FORCE_DISABLED; |
| } else { |
| pr_info("SMT: disabled\n"); |
| cpu_smt_control = CPU_SMT_DISABLED; |
| } |
| } |
| |
| /* |
| * The decision whether SMT is supported can only be done after the full |
| * CPU identification. Called from architecture code. |
| */ |
| void __init cpu_smt_check_topology(void) |
| { |
| if (!topology_smt_supported()) |
| cpu_smt_control = CPU_SMT_NOT_SUPPORTED; |
| } |
| |
| static int __init smt_cmdline_disable(char *str) |
| { |
| cpu_smt_disable(str && !strcmp(str, "force")); |
| return 0; |
| } |
| early_param("nosmt", smt_cmdline_disable); |
| |
| static inline bool cpu_smt_allowed(unsigned int cpu) |
| { |
| if (cpu_smt_control == CPU_SMT_ENABLED) |
| return true; |
| |
| if (topology_is_primary_thread(cpu)) |
| return true; |
| |
| /* |
| * On x86 it's required to boot all logical CPUs at least once so |
| * that the init code can get a chance to set CR4.MCE on each |
| * CPU. Otherwise, a broadacasted MCE observing CR4.MCE=0b on any |
| * core will shutdown the machine. |
| */ |
| return !per_cpu(cpuhp_state, cpu).booted_once; |
| } |
| #else |
| static inline bool cpu_smt_allowed(unsigned int cpu) { return true; } |
| #endif |
| |
| static inline enum cpuhp_state |
| cpuhp_set_state(struct cpuhp_cpu_state *st, enum cpuhp_state target) |
| { |
| enum cpuhp_state prev_state = st->state; |
| |
| st->rollback = false; |
| st->last = NULL; |
| |
| st->target = target; |
| st->single = false; |
| st->bringup = st->state < target; |
| |
| return prev_state; |
| } |
| |
| static inline void |
| cpuhp_reset_state(struct cpuhp_cpu_state *st, enum cpuhp_state prev_state) |
| { |
| st->rollback = true; |
| |
| /* |
| * If we have st->last we need to undo partial multi_instance of this |
| * state first. Otherwise start undo at the previous state. |
| */ |
| if (!st->last) { |
| if (st->bringup) |
| st->state--; |
| else |
| st->state++; |
| } |
| |
| st->target = prev_state; |
| st->bringup = !st->bringup; |
| } |
| |
| /* Regular hotplug invocation of the AP hotplug thread */ |
| static void __cpuhp_kick_ap(struct cpuhp_cpu_state *st) |
| { |
| if (!st->single && st->state == st->target) |
| return; |
| |
| st->result = 0; |
| /* |
| * Make sure the above stores are visible before should_run becomes |
| * true. Paired with the mb() above in cpuhp_thread_fun() |
| */ |
| smp_mb(); |
| st->should_run = true; |
| wake_up_process(st->thread); |
| wait_for_ap_thread(st, st->bringup); |
| } |
| |
| static int cpuhp_kick_ap(struct cpuhp_cpu_state *st, enum cpuhp_state target) |
| { |
| enum cpuhp_state prev_state; |
| int ret; |
| |
| prev_state = cpuhp_set_state(st, target); |
| __cpuhp_kick_ap(st); |
| if ((ret = st->result)) { |
| cpuhp_reset_state(st, prev_state); |
| __cpuhp_kick_ap(st); |
| } |
| |
| return ret; |
| } |
| |
| static int bringup_wait_for_ap(unsigned int cpu) |
| { |
| struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); |
| |
| /* Wait for the CPU to reach CPUHP_AP_ONLINE_IDLE */ |
| wait_for_ap_thread(st, true); |
| if (WARN_ON_ONCE((!cpu_online(cpu)))) |
| return -ECANCELED; |
| |
| /* Unpark the hotplug thread of the target cpu */ |
| kthread_unpark(st->thread); |
| |
| /* |
| * SMT soft disabling on X86 requires to bring the CPU out of the |
| * BIOS 'wait for SIPI' state in order to set the CR4.MCE bit. The |
| * CPU marked itself as booted_once in cpu_notify_starting() so the |
| * cpu_smt_allowed() check will now return false if this is not the |
| * primary sibling. |
| */ |
| if (!cpu_smt_allowed(cpu)) |
| return -ECANCELED; |
| |
| if (st->target <= CPUHP_AP_ONLINE_IDLE) |
| return 0; |
| |
| return cpuhp_kick_ap(st, st->target); |
| } |
| |
| static int bringup_cpu(unsigned int cpu) |
| { |
| struct task_struct *idle = idle_thread_get(cpu); |
| int ret; |
| |
| /* |
| * Some architectures have to walk the irq descriptors to |
| * setup the vector space for the cpu which comes online. |
| * Prevent irq alloc/free across the bringup. |
| */ |
| irq_lock_sparse(); |
| |
| /* Arch-specific enabling code. */ |
| ret = __cpu_up(cpu, idle); |
| irq_unlock_sparse(); |
| if (ret) |
| return ret; |
| return bringup_wait_for_ap(cpu); |
| } |
| |
| /* |
| * Hotplug state machine related functions |
| */ |
| |
| static void undo_cpu_up(unsigned int cpu, struct cpuhp_cpu_state *st) |
| { |
| for (st->state--; st->state > st->target; st->state--) { |
| struct cpuhp_step *step = cpuhp_get_step(st->state); |
| |
| if (!step->skip_onerr) |
| cpuhp_invoke_callback(cpu, st->state, false, NULL, NULL); |
| } |
| } |
| |
| static inline bool can_rollback_cpu(struct cpuhp_cpu_state *st) |
| { |
| if (IS_ENABLED(CONFIG_HOTPLUG_CPU)) |
| return true; |
| /* |
| * When CPU hotplug is disabled, then taking the CPU down is not |
| * possible because takedown_cpu() and the architecture and |
| * subsystem specific mechanisms are not available. So the CPU |
| * which would be completely unplugged again needs to stay around |
| * in the current state. |
| */ |
| return st->state <= CPUHP_BRINGUP_CPU; |
| } |
| |
| static int cpuhp_up_callbacks(unsigned int cpu, struct cpuhp_cpu_state *st, |
| enum cpuhp_state target) |
| { |
| enum cpuhp_state prev_state = st->state; |
| int ret = 0; |
| |
| while (st->state < target) { |
| st->state++; |
| ret = cpuhp_invoke_callback(cpu, st->state, true, NULL, NULL); |
| if (ret) { |
| if (can_rollback_cpu(st)) { |
| st->target = prev_state; |
| undo_cpu_up(cpu, st); |
| } |
| break; |
| } |
| } |
| return ret; |
| } |
| |
| /* |
| * The cpu hotplug threads manage the bringup and teardown of the cpus |
| */ |
| static void cpuhp_create(unsigned int cpu) |
| { |
| struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); |
| |
| init_completion(&st->done_up); |
| init_completion(&st->done_down); |
| } |
| |
| static int cpuhp_should_run(unsigned int cpu) |
| { |
| struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state); |
| |
| return st->should_run; |
| } |
| |
| /* |
| * Execute teardown/startup callbacks on the plugged cpu. Also used to invoke |
| * callbacks when a state gets [un]installed at runtime. |
| * |
| * Each invocation of this function by the smpboot thread does a single AP |
| * state callback. |
| * |
| * It has 3 modes of operation: |
| * - single: runs st->cb_state |
| * - up: runs ++st->state, while st->state < st->target |
| * - down: runs st->state--, while st->state > st->target |
| * |
| * When complete or on error, should_run is cleared and the completion is fired. |
| */ |
| static void cpuhp_thread_fun(unsigned int cpu) |
| { |
| struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state); |
| bool bringup = st->bringup; |
| enum cpuhp_state state; |
| |
| if (WARN_ON_ONCE(!st->should_run)) |
| return; |
| |
| /* |
| * ACQUIRE for the cpuhp_should_run() load of ->should_run. Ensures |
| * that if we see ->should_run we also see the rest of the state. |
| */ |
| smp_mb(); |
| |
| cpuhp_lock_acquire(bringup); |
| |
| if (st->single) { |
| state = st->cb_state; |
| st->should_run = false; |
| } else { |
| if (bringup) { |
| st->state++; |
| state = st->state; |
| st->should_run = (st->state < st->target); |
| WARN_ON_ONCE(st->state > st->target); |
| } else { |
| state = st->state; |
| st->state--; |
| st->should_run = (st->state > st->target); |
| WARN_ON_ONCE(st->state < st->target); |
| } |
| } |
| |
| WARN_ON_ONCE(!cpuhp_is_ap_state(state)); |
| |
| if (st->rollback) { |
| struct cpuhp_step *step = cpuhp_get_step(state); |
| if (step->skip_onerr) |
| goto next; |
| } |
| |
| if (cpuhp_is_atomic_state(state)) { |
| local_irq_disable(); |
| st->result = cpuhp_invoke_callback(cpu, state, bringup, st->node, &st->last); |
| local_irq_enable(); |
| |
| /* |
| * STARTING/DYING must not fail! |
| */ |
| WARN_ON_ONCE(st->result); |
| } else { |
| st->result = cpuhp_invoke_callback(cpu, state, bringup, st->node, &st->last); |
| } |
| |
| if (st->result) { |
| /* |
| * If we fail on a rollback, we're up a creek without no |
| * paddle, no way forward, no way back. We loose, thanks for |
| * playing. |
| */ |
| WARN_ON_ONCE(st->rollback); |
| st->should_run = false; |
| } |
| |
| next: |
| cpuhp_lock_release(bringup); |
| |
| if (!st->should_run) |
| complete_ap_thread(st, bringup); |
| } |
| |
| /* Invoke a single callback on a remote cpu */ |
| static int |
| cpuhp_invoke_ap_callback(int cpu, enum cpuhp_state state, bool bringup, |
| struct hlist_node *node) |
| { |
| struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); |
| int ret; |
| |
| if (!cpu_online(cpu)) |
| return 0; |
| |
| cpuhp_lock_acquire(false); |
| cpuhp_lock_release(false); |
| |
| cpuhp_lock_acquire(true); |
| cpuhp_lock_release(true); |
| |
| /* |
| * If we are up and running, use the hotplug thread. For early calls |
| * we invoke the thread function directly. |
| */ |
| if (!st->thread) |
| return cpuhp_invoke_callback(cpu, state, bringup, node, NULL); |
| |
| st->rollback = false; |
| st->last = NULL; |
| |
| st->node = node; |
| st->bringup = bringup; |
| st->cb_state = state; |
| st->single = true; |
| |
| __cpuhp_kick_ap(st); |
| |
| /* |
| * If we failed and did a partial, do a rollback. |
| */ |
| if ((ret = st->result) && st->last) { |
| st->rollback = true; |
| st->bringup = !bringup; |
| |
| __cpuhp_kick_ap(st); |
| } |
| |
| /* |
| * Clean up the leftovers so the next hotplug operation wont use stale |
| * data. |
| */ |
| st->node = st->last = NULL; |
| return ret; |
| } |
| |
| static int cpuhp_kick_ap_work(unsigned int cpu) |
| { |
| struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); |
| enum cpuhp_state prev_state = st->state; |
| int ret; |
| |
| cpuhp_lock_acquire(false); |
| cpuhp_lock_release(false); |
| |
| cpuhp_lock_acquire(true); |
| cpuhp_lock_release(true); |
| |
| trace_cpuhp_enter(cpu, st->target, prev_state, cpuhp_kick_ap_work); |
| ret = cpuhp_kick_ap(st, st->target); |
| trace_cpuhp_exit(cpu, st->state, prev_state, ret); |
| |
| return ret; |
| } |
| |
| static struct smp_hotplug_thread cpuhp_threads = { |
| .store = &cpuhp_state.thread, |
| .create = &cpuhp_create, |
| .thread_should_run = cpuhp_should_run, |
| .thread_fn = cpuhp_thread_fun, |
| .thread_comm = "cpuhp/%u", |
| .selfparking = true, |
| }; |
| |
| void __init cpuhp_threads_init(void) |
| { |
| BUG_ON(smpboot_register_percpu_thread(&cpuhp_threads)); |
| kthread_unpark(this_cpu_read(cpuhp_state.thread)); |
| } |
| |
| #ifdef CONFIG_HOTPLUG_CPU |
| /** |
| * clear_tasks_mm_cpumask - Safely clear tasks' mm_cpumask for a CPU |
| * @cpu: a CPU id |
| * |
| * This function walks all processes, finds a valid mm struct for each one and |
| * then clears a corresponding bit in mm's cpumask. While this all sounds |
| * trivial, there are various non-obvious corner cases, which this function |
| * tries to solve in a safe manner. |
| * |
| * Also note that the function uses a somewhat relaxed locking scheme, so it may |
| * be called only for an already offlined CPU. |
| */ |
| void clear_tasks_mm_cpumask(int cpu) |
| { |
| struct task_struct *p; |
| |
| /* |
| * This function is called after the cpu is taken down and marked |
| * offline, so its not like new tasks will ever get this cpu set in |
| * their mm mask. -- Peter Zijlstra |
| * Thus, we may use rcu_read_lock() here, instead of grabbing |
| * full-fledged tasklist_lock. |
| */ |
| WARN_ON(cpu_online(cpu)); |
| rcu_read_lock(); |
| for_each_process(p) { |
| struct task_struct *t; |
| |
| /* |
| * Main thread might exit, but other threads may still have |
| * a valid mm. Find one. |
| */ |
| t = find_lock_task_mm(p); |
| if (!t) |
| continue; |
| cpumask_clear_cpu(cpu, mm_cpumask(t->mm)); |
| task_unlock(t); |
| } |
| rcu_read_unlock(); |
| } |
| |
| /* Take this CPU down. */ |
| static int take_cpu_down(void *_param) |
| { |
| struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state); |
| enum cpuhp_state target = max((int)st->target, CPUHP_AP_OFFLINE); |
| int err, cpu = smp_processor_id(); |
| int ret; |
| |
| /* Ensure this CPU doesn't handle any more interrupts. */ |
| err = __cpu_disable(); |
| if (err < 0) |
| return err; |
| |
| /* |
| * We get here while we are in CPUHP_TEARDOWN_CPU state and we must not |
| * do this step again. |
| */ |
| WARN_ON(st->state != CPUHP_TEARDOWN_CPU); |
| st->state--; |
| /* Invoke the former CPU_DYING callbacks */ |
| for (; st->state > target; st->state--) { |
| ret = cpuhp_invoke_callback(cpu, st->state, false, NULL, NULL); |
| /* |
| * DYING must not fail! |
| */ |
| WARN_ON_ONCE(ret); |
| } |
| |
| /* Give up timekeeping duties */ |
| tick_handover_do_timer(); |
| /* Park the stopper thread */ |
| stop_machine_park(cpu); |
| return 0; |
| } |
| |
| static int takedown_cpu(unsigned int cpu) |
| { |
| struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); |
| int err; |
| |
| /* Park the smpboot threads */ |
| kthread_park(per_cpu_ptr(&cpuhp_state, cpu)->thread); |
| |
| /* |
| * Prevent irq alloc/free while the dying cpu reorganizes the |
| * interrupt affinities. |
| */ |
| irq_lock_sparse(); |
| |
| /* |
| * So now all preempt/rcu users must observe !cpu_active(). |
| */ |
| err = stop_machine_cpuslocked(take_cpu_down, NULL, cpumask_of(cpu)); |
| if (err) { |
| /* CPU refused to die */ |
| irq_unlock_sparse(); |
| /* Unpark the hotplug thread so we can rollback there */ |
| kthread_unpark(per_cpu_ptr(&cpuhp_state, cpu)->thread); |
| return err; |
| } |
| BUG_ON(cpu_online(cpu)); |
| |
| /* |
| * The CPUHP_AP_SCHED_MIGRATE_DYING callback will have removed all |
| * runnable tasks from the cpu, there's only the idle task left now |
| * that the migration thread is done doing the stop_machine thing. |
| * |
| * Wait for the stop thread to go away. |
| */ |
| wait_for_ap_thread(st, false); |
| BUG_ON(st->state != CPUHP_AP_IDLE_DEAD); |
| |
| /* Interrupts are moved away from the dying cpu, reenable alloc/free */ |
| irq_unlock_sparse(); |
| |
| hotplug_cpu__broadcast_tick_pull(cpu); |
| /* This actually kills the CPU. */ |
| __cpu_die(cpu); |
| |
| tick_cleanup_dead_cpu(cpu); |
| rcutree_migrate_callbacks(cpu); |
| return 0; |
| } |
| |
| static void cpuhp_complete_idle_dead(void *arg) |
| { |
| struct cpuhp_cpu_state *st = arg; |
| |
| complete_ap_thread(st, false); |
| } |
| |
| void cpuhp_report_idle_dead(void) |
| { |
| struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state); |
| |
| BUG_ON(st->state != CPUHP_AP_OFFLINE); |
| rcu_report_dead(smp_processor_id()); |
| st->state = CPUHP_AP_IDLE_DEAD; |
| /* |
| * We cannot call complete after rcu_report_dead() so we delegate it |
| * to an online cpu. |
| */ |
| smp_call_function_single(cpumask_first(cpu_online_mask), |
| cpuhp_complete_idle_dead, st, 0); |
| } |
| |
| static void undo_cpu_down(unsigned int cpu, struct cpuhp_cpu_state *st) |
| { |
| for (st->state++; st->state < st->target; st->state++) { |
| struct cpuhp_step *step = cpuhp_get_step(st->state); |
| |
| if (!step->skip_onerr) |
| cpuhp_invoke_callback(cpu, st->state, true, NULL, NULL); |
| } |
| } |
| |
| static int cpuhp_down_callbacks(unsigned int cpu, struct cpuhp_cpu_state *st, |
| enum cpuhp_state target) |
| { |
| enum cpuhp_state prev_state = st->state; |
| int ret = 0; |
| |
| for (; st->state > target; st->state--) { |
| ret = cpuhp_invoke_callback(cpu, st->state, false, NULL, NULL); |
| if (ret) { |
| st->target = prev_state; |
| if (st->state < prev_state) |
| undo_cpu_down(cpu, st); |
| break; |
| } |
| } |
| return ret; |
| } |
| |
| /* Requires cpu_add_remove_lock to be held */ |
| static int __ref _cpu_down(unsigned int cpu, int tasks_frozen, |
| enum cpuhp_state target) |
| { |
| struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); |
| int prev_state, ret = 0; |
| |
| if (num_online_cpus() == 1) |
| return -EBUSY; |
| |
| if (!cpu_present(cpu)) |
| return -EINVAL; |
| |
| cpus_write_lock(); |
| |
| cpuhp_tasks_frozen = tasks_frozen; |
| |
| prev_state = cpuhp_set_state(st, target); |
| /* |
| * If the current CPU state is in the range of the AP hotplug thread, |
| * then we need to kick the thread. |
| */ |
| if (st->state > CPUHP_TEARDOWN_CPU) { |
| st->target = max((int)target, CPUHP_TEARDOWN_CPU); |
| ret = cpuhp_kick_ap_work(cpu); |
| /* |
| * The AP side has done the error rollback already. Just |
| * return the error code.. |
| */ |
| if (ret) |
| goto out; |
| |
| /* |
| * We might have stopped still in the range of the AP hotplug |
| * thread. Nothing to do anymore. |
| */ |
| if (st->state > CPUHP_TEARDOWN_CPU) |
| goto out; |
| |
| st->target = target; |
| } |
| /* |
| * The AP brought itself down to CPUHP_TEARDOWN_CPU. So we need |
| * to do the further cleanups. |
| */ |
| ret = cpuhp_down_callbacks(cpu, st, target); |
| if (ret && st->state == CPUHP_TEARDOWN_CPU && st->state < prev_state) { |
| cpuhp_reset_state(st, prev_state); |
| __cpuhp_kick_ap(st); |
| } |
| |
| out: |
| cpus_write_unlock(); |
| /* |
| * Do post unplug cleanup. This is still protected against |
| * concurrent CPU hotplug via cpu_add_remove_lock. |
| */ |
| lockup_detector_cleanup(); |
| arch_smt_update(); |
| return ret; |
| } |
| |
| static int cpu_down_maps_locked(unsigned int cpu, enum cpuhp_state target) |
| { |
| if (cpu_hotplug_disabled) |
| return -EBUSY; |
| return _cpu_down(cpu, 0, target); |
| } |
| |
| static int do_cpu_down(unsigned int cpu, enum cpuhp_state target) |
| { |
| int err; |
| |
| cpu_maps_update_begin(); |
| err = cpu_down_maps_locked(cpu, target); |
| cpu_maps_update_done(); |
| return err; |
| } |
| |
| int cpu_down(unsigned int cpu) |
| { |
| return do_cpu_down(cpu, CPUHP_OFFLINE); |
| } |
| EXPORT_SYMBOL(cpu_down); |
| |
| #else |
| #define takedown_cpu NULL |
| #endif /*CONFIG_HOTPLUG_CPU*/ |
| |
| /** |
| * notify_cpu_starting(cpu) - Invoke the callbacks on the starting CPU |
| * @cpu: cpu that just started |
| * |
| * It must be called by the arch code on the new cpu, before the new cpu |
| * enables interrupts and before the "boot" cpu returns from __cpu_up(). |
| */ |
| void notify_cpu_starting(unsigned int cpu) |
| { |
| struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); |
| enum cpuhp_state target = min((int)st->target, CPUHP_AP_ONLINE); |
| int ret; |
| |
| rcu_cpu_starting(cpu); /* Enables RCU usage on this CPU. */ |
| st->booted_once = true; |
| while (st->state < target) { |
| st->state++; |
| ret = cpuhp_invoke_callback(cpu, st->state, true, NULL, NULL); |
| /* |
| * STARTING must not fail! |
| */ |
| WARN_ON_ONCE(ret); |
| } |
| } |
| |
| /* |
| * Called from the idle task. Wake up the controlling task which brings the |
| * hotplug thread of the upcoming CPU up and then delegates the rest of the |
| * online bringup to the hotplug thread. |
| */ |
| void cpuhp_online_idle(enum cpuhp_state state) |
| { |
| struct cpuhp_cpu_state *st = this_cpu_ptr(&cpuhp_state); |
| |
| /* Happens for the boot cpu */ |
| if (state != CPUHP_AP_ONLINE_IDLE) |
| return; |
| |
| /* |
| * Unpart the stopper thread before we start the idle loop (and start |
| * scheduling); this ensures the stopper task is always available. |
| */ |
| stop_machine_unpark(smp_processor_id()); |
| |
| st->state = CPUHP_AP_ONLINE_IDLE; |
| complete_ap_thread(st, true); |
| } |
| |
| /* Requires cpu_add_remove_lock to be held */ |
| static int _cpu_up(unsigned int cpu, int tasks_frozen, enum cpuhp_state target) |
| { |
| struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); |
| struct task_struct *idle; |
| int ret = 0; |
| |
| cpus_write_lock(); |
| |
| if (!cpu_present(cpu)) { |
| ret = -EINVAL; |
| goto out; |
| } |
| |
| /* |
| * The caller of do_cpu_up might have raced with another |
| * caller. Ignore it for now. |
| */ |
| if (st->state >= target) |
| goto out; |
| |
| if (st->state == CPUHP_OFFLINE) { |
| /* Let it fail before we try to bring the cpu up */ |
| idle = idle_thread_get(cpu); |
| if (IS_ERR(idle)) { |
| ret = PTR_ERR(idle); |
| goto out; |
| } |
| } |
| |
| cpuhp_tasks_frozen = tasks_frozen; |
| |
| cpuhp_set_state(st, target); |
| /* |
| * If the current CPU state is in the range of the AP hotplug thread, |
| * then we need to kick the thread once more. |
| */ |
| if (st->state > CPUHP_BRINGUP_CPU) { |
| ret = cpuhp_kick_ap_work(cpu); |
| /* |
| * The AP side has done the error rollback already. Just |
| * return the error code.. |
| */ |
| if (ret) |
| goto out; |
| } |
| |
| /* |
| * Try to reach the target state. We max out on the BP at |
| * CPUHP_BRINGUP_CPU. After that the AP hotplug thread is |
| * responsible for bringing it up to the target state. |
| */ |
| target = min((int)target, CPUHP_BRINGUP_CPU); |
| ret = cpuhp_up_callbacks(cpu, st, target); |
| out: |
| cpus_write_unlock(); |
| arch_smt_update(); |
| return ret; |
| } |
| |
| static int do_cpu_up(unsigned int cpu, enum cpuhp_state target) |
| { |
| int err = 0; |
| |
| if (!cpu_possible(cpu)) { |
| pr_err("can't online cpu %d because it is not configured as may-hotadd at boot time\n", |
| cpu); |
| #if defined(CONFIG_IA64) |
| pr_err("please check additional_cpus= boot parameter\n"); |
| #endif |
| return -EINVAL; |
| } |
| |
| err = try_online_node(cpu_to_node(cpu)); |
| if (err) |
| return err; |
| |
| cpu_maps_update_begin(); |
| |
| if (cpu_hotplug_disabled) { |
| err = -EBUSY; |
| goto out; |
| } |
| if (!cpu_smt_allowed(cpu)) { |
| err = -EPERM; |
| goto out; |
| } |
| |
| err = _cpu_up(cpu, 0, target); |
| out: |
| cpu_maps_update_done(); |
| return err; |
| } |
| |
| int cpu_up(unsigned int cpu) |
| { |
| return do_cpu_up(cpu, CPUHP_ONLINE); |
| } |
| EXPORT_SYMBOL_GPL(cpu_up); |
| |
| #ifdef CONFIG_PM_SLEEP_SMP |
| static cpumask_var_t frozen_cpus; |
| |
| int freeze_secondary_cpus(int primary) |
| { |
| int cpu, error = 0; |
| |
| cpu_maps_update_begin(); |
| if (!cpu_online(primary)) |
| primary = cpumask_first(cpu_online_mask); |
| /* |
| * We take down all of the non-boot CPUs in one shot to avoid races |
| * with the userspace trying to use the CPU hotplug at the same time |
| */ |
| cpumask_clear(frozen_cpus); |
| |
| pr_info("Disabling non-boot CPUs ...\n"); |
| for_each_online_cpu(cpu) { |
| if (cpu == primary) |
| continue; |
| trace_suspend_resume(TPS("CPU_OFF"), cpu, true); |
| error = _cpu_down(cpu, 1, CPUHP_OFFLINE); |
| trace_suspend_resume(TPS("CPU_OFF"), cpu, false); |
| if (!error) |
| cpumask_set_cpu(cpu, frozen_cpus); |
| else { |
| pr_err("Error taking CPU%d down: %d\n", cpu, error); |
| break; |
| } |
| } |
| |
| if (!error) |
| BUG_ON(num_online_cpus() > 1); |
| else |
| pr_err("Non-boot CPUs are not disabled\n"); |
| |
| /* |
| * Make sure the CPUs won't be enabled by someone else. We need to do |
| * this even in case of failure as all disable_nonboot_cpus() users are |
| * supposed to do enable_nonboot_cpus() on the failure path. |
| */ |
| cpu_hotplug_disabled++; |
| |
| cpu_maps_update_done(); |
| return error; |
| } |
| |
| void __weak arch_enable_nonboot_cpus_begin(void) |
| { |
| } |
| |
| void __weak arch_enable_nonboot_cpus_end(void) |
| { |
| } |
| |
| void enable_nonboot_cpus(void) |
| { |
| int cpu, error; |
| |
| /* Allow everyone to use the CPU hotplug again */ |
| cpu_maps_update_begin(); |
| __cpu_hotplug_enable(); |
| if (cpumask_empty(frozen_cpus)) |
| goto out; |
| |
| pr_info("Enabling non-boot CPUs ...\n"); |
| |
| arch_enable_nonboot_cpus_begin(); |
| |
| for_each_cpu(cpu, frozen_cpus) { |
| trace_suspend_resume(TPS("CPU_ON"), cpu, true); |
| error = _cpu_up(cpu, 1, CPUHP_ONLINE); |
| trace_suspend_resume(TPS("CPU_ON"), cpu, false); |
| if (!error) { |
| pr_info("CPU%d is up\n", cpu); |
| continue; |
| } |
| pr_warn("Error taking CPU%d up: %d\n", cpu, error); |
| } |
| |
| arch_enable_nonboot_cpus_end(); |
| |
| cpumask_clear(frozen_cpus); |
| out: |
| cpu_maps_update_done(); |
| } |
| |
| static int __init alloc_frozen_cpus(void) |
| { |
| if (!alloc_cpumask_var(&frozen_cpus, GFP_KERNEL|__GFP_ZERO)) |
| return -ENOMEM; |
| return 0; |
| } |
| core_initcall(alloc_frozen_cpus); |
| |
| /* |
| * When callbacks for CPU hotplug notifications are being executed, we must |
| * ensure that the state of the system with respect to the tasks being frozen |
| * or not, as reported by the notification, remains unchanged *throughout the |
| * duration* of the execution of the callbacks. |
| * Hence we need to prevent the freezer from racing with regular CPU hotplug. |
| * |
| * This synchronization is implemented by mutually excluding regular CPU |
| * hotplug and Suspend/Hibernate call paths by hooking onto the Suspend/ |
| * Hibernate notifications. |
| */ |
| static int |
| cpu_hotplug_pm_callback(struct notifier_block *nb, |
| unsigned long action, void *ptr) |
| { |
| switch (action) { |
| |
| case PM_SUSPEND_PREPARE: |
| case PM_HIBERNATION_PREPARE: |
| cpu_hotplug_disable(); |
| break; |
| |
| case PM_POST_SUSPEND: |
| case PM_POST_HIBERNATION: |
| cpu_hotplug_enable(); |
| break; |
| |
| default: |
| return NOTIFY_DONE; |
| } |
| |
| return NOTIFY_OK; |
| } |
| |
| |
| static int __init cpu_hotplug_pm_sync_init(void) |
| { |
| /* |
| * cpu_hotplug_pm_callback has higher priority than x86 |
| * bsp_pm_callback which depends on cpu_hotplug_pm_callback |
| * to disable cpu hotplug to avoid cpu hotplug race. |
| */ |
| pm_notifier(cpu_hotplug_pm_callback, 0); |
| return 0; |
| } |
| core_initcall(cpu_hotplug_pm_sync_init); |
| |
| #endif /* CONFIG_PM_SLEEP_SMP */ |
| |
| int __boot_cpu_id; |
| |
| #endif /* CONFIG_SMP */ |
| |
| /* Boot processor state steps */ |
| static struct cpuhp_step cpuhp_bp_states[] = { |
| [CPUHP_OFFLINE] = { |
| .name = "offline", |
| .startup.single = NULL, |
| .teardown.single = NULL, |
| }, |
| #ifdef CONFIG_SMP |
| [CPUHP_CREATE_THREADS]= { |
| .name = "threads:prepare", |
| .startup.single = smpboot_create_threads, |
| .teardown.single = NULL, |
| .cant_stop = true, |
| }, |
| [CPUHP_PERF_PREPARE] = { |
| .name = "perf:prepare", |
| .startup.single = perf_event_init_cpu, |
| .teardown.single = perf_event_exit_cpu, |
| }, |
| [CPUHP_WORKQUEUE_PREP] = { |
| .name = "workqueue:prepare", |
| .startup.single = workqueue_prepare_cpu, |
| .teardown.single = NULL, |
| }, |
| [CPUHP_HRTIMERS_PREPARE] = { |
| .name = "hrtimers:prepare", |
| .startup.single = hrtimers_prepare_cpu, |
| .teardown.single = hrtimers_dead_cpu, |
| }, |
| [CPUHP_SMPCFD_PREPARE] = { |
| .name = "smpcfd:prepare", |
| .startup.single = smpcfd_prepare_cpu, |
| .teardown.single = smpcfd_dead_cpu, |
| }, |
| [CPUHP_RELAY_PREPARE] = { |
| .name = "relay:prepare", |
| .startup.single = relay_prepare_cpu, |
| .teardown.single = NULL, |
| }, |
| [CPUHP_SLAB_PREPARE] = { |
| .name = "slab:prepare", |
| .startup.single = slab_prepare_cpu, |
| .teardown.single = slab_dead_cpu, |
| }, |
| [CPUHP_RCUTREE_PREP] = { |
| .name = "RCU/tree:prepare", |
| .startup.single = rcutree_prepare_cpu, |
| .teardown.single = rcutree_dead_cpu, |
| }, |
| /* |
| * On the tear-down path, timers_dead_cpu() must be invoked |
| * before blk_mq_queue_reinit_notify() from notify_dead(), |
| * otherwise a RCU stall occurs. |
| */ |
| [CPUHP_TIMERS_PREPARE] = { |
| .name = "timers:dead", |
| .startup.single = timers_prepare_cpu, |
| .teardown.single = timers_dead_cpu, |
| }, |
| /* Kicks the plugged cpu into life */ |
| [CPUHP_BRINGUP_CPU] = { |
| .name = "cpu:bringup", |
| .startup.single = bringup_cpu, |
| .teardown.single = NULL, |
| .cant_stop = true, |
| }, |
| /* |
| * Handled on controll processor until the plugged processor manages |
| * this itself. |
| */ |
| [CPUHP_TEARDOWN_CPU] = { |
| .name = "cpu:teardown", |
| .startup.single = NULL, |
| .teardown.single = takedown_cpu, |
| .cant_stop = true, |
| }, |
| #else |
| [CPUHP_BRINGUP_CPU] = { }, |
| #endif |
| }; |
| |
| /* Application processor state steps */ |
| static struct cpuhp_step cpuhp_ap_states[] = { |
| #ifdef CONFIG_SMP |
| /* Final state before CPU kills itself */ |
| [CPUHP_AP_IDLE_DEAD] = { |
| .name = "idle:dead", |
| }, |
| /* |
| * Last state before CPU enters the idle loop to die. Transient state |
| * for synchronization. |
| */ |
| [CPUHP_AP_OFFLINE] = { |
| .name = "ap:offline", |
| .cant_stop = true, |
| }, |
| /* First state is scheduler control. Interrupts are disabled */ |
| [CPUHP_AP_SCHED_STARTING] = { |
| .name = "sched:starting", |
| .startup.single = sched_cpu_starting, |
| .teardown.single = sched_cpu_dying, |
| }, |
| [CPUHP_AP_RCUTREE_DYING] = { |
| .name = "RCU/tree:dying", |
| .startup.single = NULL, |
| .teardown.single = rcutree_dying_cpu, |
| }, |
| [CPUHP_AP_SMPCFD_DYING] = { |
| .name = "smpcfd:dying", |
| .startup.single = NULL, |
| .teardown.single = smpcfd_dying_cpu, |
| }, |
| /* Entry state on starting. Interrupts enabled from here on. Transient |
| * state for synchronsization */ |
| [CPUHP_AP_ONLINE] = { |
| .name = "ap:online", |
| }, |
| /* Handle smpboot threads park/unpark */ |
| [CPUHP_AP_SMPBOOT_THREADS] = { |
| .name = "smpboot/threads:online", |
| .startup.single = smpboot_unpark_threads, |
| .teardown.single = smpboot_park_threads, |
| }, |
| [CPUHP_AP_IRQ_AFFINITY_ONLINE] = { |
| .name = "irq/affinity:online", |
| .startup.single = irq_affinity_online_cpu, |
| .teardown.single = NULL, |
| }, |
| [CPUHP_AP_PERF_ONLINE] = { |
| .name = "perf:online", |
| .startup.single = perf_event_init_cpu, |
| .teardown.single = perf_event_exit_cpu, |
| }, |
| [CPUHP_AP_WORKQUEUE_ONLINE] = { |
| .name = "workqueue:online", |
| .startup.single = workqueue_online_cpu, |
| .teardown.single = workqueue_offline_cpu, |
| }, |
| [CPUHP_AP_RCUTREE_ONLINE] = { |
| .name = "RCU/tree:online", |
| .startup.single = rcutree_online_cpu, |
| .teardown.single = rcutree_offline_cpu, |
| }, |
| #endif |
| /* |
| * The dynamically registered state space is here |
| */ |
| |
| #ifdef CONFIG_SMP |
| /* Last state is scheduler control setting the cpu active */ |
| [CPUHP_AP_ACTIVE] = { |
| .name = "sched:active", |
| .startup.single = sched_cpu_activate, |
| .teardown.single = sched_cpu_deactivate, |
| }, |
| #endif |
| |
| /* CPU is fully up and running. */ |
| [CPUHP_ONLINE] = { |
| .name = "online", |
| .startup.single = NULL, |
| .teardown.single = NULL, |
| }, |
| }; |
| |
| /* Sanity check for callbacks */ |
| static int cpuhp_cb_check(enum cpuhp_state state) |
| { |
| if (state <= CPUHP_OFFLINE || state >= CPUHP_ONLINE) |
| return -EINVAL; |
| return 0; |
| } |
| |
| /* |
| * Returns a free for dynamic slot assignment of the Online state. The states |
| * are protected by the cpuhp_slot_states mutex and an empty slot is identified |
| * by having no name assigned. |
| */ |
| static int cpuhp_reserve_state(enum cpuhp_state state) |
| { |
| enum cpuhp_state i, end; |
| struct cpuhp_step *step; |
| |
| switch (state) { |
| case CPUHP_AP_ONLINE_DYN: |
| step = cpuhp_ap_states + CPUHP_AP_ONLINE_DYN; |
| end = CPUHP_AP_ONLINE_DYN_END; |
| break; |
| case CPUHP_BP_PREPARE_DYN: |
| step = cpuhp_bp_states + CPUHP_BP_PREPARE_DYN; |
| end = CPUHP_BP_PREPARE_DYN_END; |
| break; |
| default: |
| return -EINVAL; |
| } |
| |
| for (i = state; i <= end; i++, step++) { |
| if (!step->name) |
| return i; |
| } |
| WARN(1, "No more dynamic states available for CPU hotplug\n"); |
| return -ENOSPC; |
| } |
| |
| static int cpuhp_store_callbacks(enum cpuhp_state state, const char *name, |
| int (*startup)(unsigned int cpu), |
| int (*teardown)(unsigned int cpu), |
| bool multi_instance) |
| { |
| /* (Un)Install the callbacks for further cpu hotplug operations */ |
| struct cpuhp_step *sp; |
| int ret = 0; |
| |
| /* |
| * If name is NULL, then the state gets removed. |
| * |
| * CPUHP_AP_ONLINE_DYN and CPUHP_BP_PREPARE_DYN are handed out on |
| * the first allocation from these dynamic ranges, so the removal |
| * would trigger a new allocation and clear the wrong (already |
| * empty) state, leaving the callbacks of the to be cleared state |
| * dangling, which causes wreckage on the next hotplug operation. |
| */ |
| if (name && (state == CPUHP_AP_ONLINE_DYN || |
| state == CPUHP_BP_PREPARE_DYN)) { |
| ret = cpuhp_reserve_state(state); |
| if (ret < 0) |
| return ret; |
| state = ret; |
| } |
| sp = cpuhp_get_step(state); |
| if (name && sp->name) |
| return -EBUSY; |
| |
| sp->startup.single = startup; |
| sp->teardown.single = teardown; |
| sp->name = name; |
| sp->multi_instance = multi_instance; |
| INIT_HLIST_HEAD(&sp->list); |
| return ret; |
| } |
| |
| static void *cpuhp_get_teardown_cb(enum cpuhp_state state) |
| { |
| return cpuhp_get_step(state)->teardown.single; |
| } |
| |
| /* |
| * Call the startup/teardown function for a step either on the AP or |
| * on the current CPU. |
| */ |
| static int cpuhp_issue_call(int cpu, enum cpuhp_state state, bool bringup, |
| struct hlist_node *node) |
| { |
| struct cpuhp_step *sp = cpuhp_get_step(state); |
| int ret; |
| |
| /* |
| * If there's nothing to do, we done. |
| * Relies on the union for multi_instance. |
| */ |
| if ((bringup && !sp->startup.single) || |
| (!bringup && !sp->teardown.single)) |
| return 0; |
| /* |
| * The non AP bound callbacks can fail on bringup. On teardown |
| * e.g. module removal we crash for now. |
| */ |
| #ifdef CONFIG_SMP |
| if (cpuhp_is_ap_state(state)) |
| ret = cpuhp_invoke_ap_callback(cpu, state, bringup, node); |
| else |
| ret = cpuhp_invoke_callback(cpu, state, bringup, node, NULL); |
| #else |
| ret = cpuhp_invoke_callback(cpu, state, bringup, node, NULL); |
| #endif |
| BUG_ON(ret && !bringup); |
| return ret; |
| } |
| |
| /* |
| * Called from __cpuhp_setup_state on a recoverable failure. |
| * |
| * Note: The teardown callbacks for rollback are not allowed to fail! |
| */ |
| static void cpuhp_rollback_install(int failedcpu, enum cpuhp_state state, |
| struct hlist_node *node) |
| { |
| int cpu; |
| |
| /* Roll back the already executed steps on the other cpus */ |
| for_each_present_cpu(cpu) { |
| struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); |
| int cpustate = st->state; |
| |
| if (cpu >= failedcpu) |
| break; |
| |
| /* Did we invoke the startup call on that cpu ? */ |
| if (cpustate >= state) |
| cpuhp_issue_call(cpu, state, false, node); |
| } |
| } |
| |
| int __cpuhp_state_add_instance_cpuslocked(enum cpuhp_state state, |
| struct hlist_node *node, |
| bool invoke) |
| { |
| struct cpuhp_step *sp; |
| int cpu; |
| int ret; |
| |
| lockdep_assert_cpus_held(); |
| |
| sp = cpuhp_get_step(state); |
| if (sp->multi_instance == false) |
| return -EINVAL; |
| |
| mutex_lock(&cpuhp_state_mutex); |
| |
| if (!invoke || !sp->startup.multi) |
| goto add_node; |
| |
| /* |
| * Try to call the startup callback for each present cpu |
| * depending on the hotplug state of the cpu. |
| */ |
| for_each_present_cpu(cpu) { |
| struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); |
| int cpustate = st->state; |
| |
| if (cpustate < state) |
| continue; |
| |
| ret = cpuhp_issue_call(cpu, state, true, node); |
| if (ret) { |
| if (sp->teardown.multi) |
| cpuhp_rollback_install(cpu, state, node); |
| goto unlock; |
| } |
| } |
| add_node: |
| ret = 0; |
| hlist_add_head(node, &sp->list); |
| unlock: |
| mutex_unlock(&cpuhp_state_mutex); |
| return ret; |
| } |
| |
| int __cpuhp_state_add_instance(enum cpuhp_state state, struct hlist_node *node, |
| bool invoke) |
| { |
| int ret; |
| |
| cpus_read_lock(); |
| ret = __cpuhp_state_add_instance_cpuslocked(state, node, invoke); |
| cpus_read_unlock(); |
| return ret; |
| } |
| EXPORT_SYMBOL_GPL(__cpuhp_state_add_instance); |
| |
| /** |
| * __cpuhp_setup_state_cpuslocked - Setup the callbacks for an hotplug machine state |
| * @state: The state to setup |
| * @invoke: If true, the startup function is invoked for cpus where |
| * cpu state >= @state |
| * @startup: startup callback function |
| * @teardown: teardown callback function |
| * @multi_instance: State is set up for multiple instances which get |
| * added afterwards. |
| * |
| * The caller needs to hold cpus read locked while calling this function. |
| * Returns: |
| * On success: |
| * Positive state number if @state is CPUHP_AP_ONLINE_DYN |
| * 0 for all other states |
| * On failure: proper (negative) error code |
| */ |
| int __cpuhp_setup_state_cpuslocked(enum cpuhp_state state, |
| const char *name, bool invoke, |
| int (*startup)(unsigned int cpu), |
| int (*teardown)(unsigned int cpu), |
| bool multi_instance) |
| { |
| int cpu, ret = 0; |
| bool dynstate; |
| |
| lockdep_assert_cpus_held(); |
| |
| if (cpuhp_cb_check(state) || !name) |
| return -EINVAL; |
| |
| mutex_lock(&cpuhp_state_mutex); |
| |
| ret = cpuhp_store_callbacks(state, name, startup, teardown, |
| multi_instance); |
| |
| dynstate = state == CPUHP_AP_ONLINE_DYN; |
| if (ret > 0 && dynstate) { |
| state = ret; |
| ret = 0; |
| } |
| |
| if (ret || !invoke || !startup) |
| goto out; |
| |
| /* |
| * Try to call the startup callback for each present cpu |
| * depending on the hotplug state of the cpu. |
| */ |
| for_each_present_cpu(cpu) { |
| struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); |
| int cpustate = st->state; |
| |
| if (cpustate < state) |
| continue; |
| |
| ret = cpuhp_issue_call(cpu, state, true, NULL); |
| if (ret) { |
| if (teardown) |
| cpuhp_rollback_install(cpu, state, NULL); |
| cpuhp_store_callbacks(state, NULL, NULL, NULL, false); |
| goto out; |
| } |
| } |
| out: |
| mutex_unlock(&cpuhp_state_mutex); |
| /* |
| * If the requested state is CPUHP_AP_ONLINE_DYN, return the |
| * dynamically allocated state in case of success. |
| */ |
| if (!ret && dynstate) |
| return state; |
| return ret; |
| } |
| EXPORT_SYMBOL(__cpuhp_setup_state_cpuslocked); |
| |
| int __cpuhp_setup_state(enum cpuhp_state state, |
| const char *name, bool invoke, |
| int (*startup)(unsigned int cpu), |
| int (*teardown)(unsigned int cpu), |
| bool multi_instance) |
| { |
| int ret; |
| |
| cpus_read_lock(); |
| ret = __cpuhp_setup_state_cpuslocked(state, name, invoke, startup, |
| teardown, multi_instance); |
| cpus_read_unlock(); |
| return ret; |
| } |
| EXPORT_SYMBOL(__cpuhp_setup_state); |
| |
| int __cpuhp_state_remove_instance(enum cpuhp_state state, |
| struct hlist_node *node, bool invoke) |
| { |
| struct cpuhp_step *sp = cpuhp_get_step(state); |
| int cpu; |
| |
| BUG_ON(cpuhp_cb_check(state)); |
| |
| if (!sp->multi_instance) |
| return -EINVAL; |
| |
| cpus_read_lock(); |
| mutex_lock(&cpuhp_state_mutex); |
| |
| if (!invoke || !cpuhp_get_teardown_cb(state)) |
| goto remove; |
| /* |
| * Call the teardown callback for each present cpu depending |
| * on the hotplug state of the cpu. This function is not |
| * allowed to fail currently! |
| */ |
| for_each_present_cpu(cpu) { |
| struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); |
| int cpustate = st->state; |
| |
| if (cpustate >= state) |
| cpuhp_issue_call(cpu, state, false, node); |
| } |
| |
| remove: |
| hlist_del(node); |
| mutex_unlock(&cpuhp_state_mutex); |
| cpus_read_unlock(); |
| |
| return 0; |
| } |
| EXPORT_SYMBOL_GPL(__cpuhp_state_remove_instance); |
| |
| /** |
| * __cpuhp_remove_state_cpuslocked - Remove the callbacks for an hotplug machine state |
| * @state: The state to remove |
| * @invoke: If true, the teardown function is invoked for cpus where |
| * cpu state >= @state |
| * |
| * The caller needs to hold cpus read locked while calling this function. |
| * The teardown callback is currently not allowed to fail. Think |
| * about module removal! |
| */ |
| void __cpuhp_remove_state_cpuslocked(enum cpuhp_state state, bool invoke) |
| { |
| struct cpuhp_step *sp = cpuhp_get_step(state); |
| int cpu; |
| |
| BUG_ON(cpuhp_cb_check(state)); |
| |
| lockdep_assert_cpus_held(); |
| |
| mutex_lock(&cpuhp_state_mutex); |
| if (sp->multi_instance) { |
| WARN(!hlist_empty(&sp->list), |
| "Error: Removing state %d which has instances left.\n", |
| state); |
| goto remove; |
| } |
| |
| if (!invoke || !cpuhp_get_teardown_cb(state)) |
| goto remove; |
| |
| /* |
| * Call the teardown callback for each present cpu depending |
| * on the hotplug state of the cpu. This function is not |
| * allowed to fail currently! |
| */ |
| for_each_present_cpu(cpu) { |
| struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu); |
| int cpustate = st->state; |
| |
| if (cpustate >= state) |
| cpuhp_issue_call(cpu, state, false, NULL); |
| } |
| remove: |
| cpuhp_store_callbacks(state, NULL, NULL, NULL, false); |
| mutex_unlock(&cpuhp_state_mutex); |
| } |
| EXPORT_SYMBOL(__cpuhp_remove_state_cpuslocked); |
| |
| void __cpuhp_remove_state(enum cpuhp_state state, bool invoke) |
| { |
| cpus_read_lock(); |
| __cpuhp_remove_state_cpuslocked(state, invoke); |
| cpus_read_unlock(); |
| } |
| EXPORT_SYMBOL(__cpuhp_remove_state); |
| |
| #if defined(CONFIG_SYSFS) && defined(CONFIG_HOTPLUG_CPU) |
| static ssize_t show_cpuhp_state(struct device *dev, |
| struct device_attribute *attr, char *buf) |
| { |
| struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, dev->id); |
| |
| return sprintf(buf, "%d\n", st->state); |
| } |
| static DEVICE_ATTR(state, 0444, show_cpuhp_state, NULL); |
| |
| static ssize_t write_cpuhp_target(struct device *dev, |
| struct device_attribute *attr, |
| const char *buf, size_t count) |
| { |
| struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, dev->id); |
| struct cpuhp_step *sp; |
| int target, ret; |
| |
| ret = kstrtoint(buf, 10, &target); |
| if (ret) |
| return ret; |
| |
| #ifdef CONFIG_CPU_HOTPLUG_STATE_CONTROL |
| if (target < CPUHP_OFFLINE || target > CPUHP_ONLINE) |
| return -EINVAL; |
| #else |
| if (target != CPUHP_OFFLINE && target != CPUHP_ONLINE) |
| return -EINVAL; |
| #endif |
| |
| ret = lock_device_hotplug_sysfs(); |
| if (ret) |
| return ret; |
| |
| mutex_lock(&cpuhp_state_mutex); |
| sp = cpuhp_get_step(target); |
| ret = !sp->name || sp->cant_stop ? -EINVAL : 0; |
| mutex_unlock(&cpuhp_state_mutex); |
| if (ret) |
| goto out; |
| |
| if (st->state < target) |
| ret = do_cpu_up(dev->id, target); |
| else |
| ret = do_cpu_down(dev->id, target); |
| out: |
| unlock_device_hotplug(); |
| return ret ? ret : count; |
| } |
| |
| static ssize_t show_cpuhp_target(struct device *dev, |
| struct device_attribute *attr, char *buf) |
| { |
| struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, dev->id); |
| |
| return sprintf(buf, "%d\n", st->target); |
| } |
| static DEVICE_ATTR(target, 0644, show_cpuhp_target, write_cpuhp_target); |
| |
| |
| static ssize_t write_cpuhp_fail(struct device *dev, |
| struct device_attribute *attr, |
| const char *buf, size_t count) |
| { |
| struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, dev->id); |
| struct cpuhp_step *sp; |
| int fail, ret; |
| |
| ret = kstrtoint(buf, 10, &fail); |
| if (ret) |
| return ret; |
| |
| if (fail < CPUHP_OFFLINE || fail > CPUHP_ONLINE) |
| return -EINVAL; |
| |
| /* |
| * Cannot fail STARTING/DYING callbacks. |
| */ |
| if (cpuhp_is_atomic_state(fail)) |
| return -EINVAL; |
| |
| /* |
| * Cannot fail anything that doesn't have callbacks. |
| */ |
| mutex_lock(&cpuhp_state_mutex); |
| sp = cpuhp_get_step(fail); |
| if (!sp->startup.single && !sp->teardown.single) |
| ret = -EINVAL; |
| mutex_unlock(&cpuhp_state_mutex); |
| if (ret) |
| return ret; |
| |
| st->fail = fail; |
| |
| return count; |
| } |
| |
| static ssize_t show_cpuhp_fail(struct device *dev, |
| struct device_attribute *attr, char *buf) |
| { |
| struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, dev->id); |
| |
| return sprintf(buf, "%d\n", st->fail); |
| } |
| |
| static DEVICE_ATTR(fail, 0644, show_cpuhp_fail, write_cpuhp_fail); |
| |
| static struct attribute *cpuhp_cpu_attrs[] = { |
| &dev_attr_state.attr, |
| &dev_attr_target.attr, |
| &dev_attr_fail.attr, |
| NULL |
| }; |
| |
| static const struct attribute_group cpuhp_cpu_attr_group = { |
| .attrs = cpuhp_cpu_attrs, |
| .name = "hotplug", |
| NULL |
| }; |
| |
| static ssize_t show_cpuhp_states(struct device *dev, |
| struct device_attribute *attr, char *buf) |
| { |
| ssize_t cur, res = 0; |
| int i; |
| |
| mutex_lock(&cpuhp_state_mutex); |
| for (i = CPUHP_OFFLINE; i <= CPUHP_ONLINE; i++) { |
| struct cpuhp_step *sp = cpuhp_get_step(i); |
| |
| if (sp->name) { |
| cur = sprintf(buf, "%3d: %s\n", i, sp->name); |
| buf += cur; |
| res += cur; |
| } |
| } |
| mutex_unlock(&cpuhp_state_mutex); |
| return res; |
| } |
| static DEVICE_ATTR(states, 0444, show_cpuhp_states, NULL); |
| |
| static struct attribute *cpuhp_cpu_root_attrs[] = { |
| &dev_attr_states.attr, |
| NULL |
| }; |
| |
| static const struct attribute_group cpuhp_cpu_root_attr_group = { |
| .attrs = cpuhp_cpu_root_attrs, |
| .name = "hotplug", |
| NULL |
| }; |
| |
| #ifdef CONFIG_HOTPLUG_SMT |
| |
| static const char *smt_states[] = { |
| [CPU_SMT_ENABLED] = "on", |
| [CPU_SMT_DISABLED] = "off", |
| [CPU_SMT_FORCE_DISABLED] = "forceoff", |
| [CPU_SMT_NOT_SUPPORTED] = "notsupported", |
| }; |
| |
| static ssize_t |
| show_smt_control(struct device *dev, struct device_attribute *attr, char *buf) |
| { |
| return snprintf(buf, PAGE_SIZE - 2, "%s\n", smt_states[cpu_smt_control]); |
| } |
| |
| 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; |
| arch_smt_update(); |
| } |
| 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; |
| arch_smt_update(); |
| 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) |
| { |
| int ctrlval, ret; |
| |
| if (sysfs_streq(buf, "on")) |
| ctrlval = CPU_SMT_ENABLED; |
| else if (sysfs_streq(buf, "off")) |
| ctrlval = CPU_SMT_DISABLED; |
| else if (sysfs_streq(buf, "forceoff")) |
| ctrlval = CPU_SMT_FORCE_DISABLED; |
| else |
| return -EINVAL; |
| |
| if (cpu_smt_control == CPU_SMT_FORCE_DISABLED) |
| return -EPERM; |
| |
| if (cpu_smt_control == CPU_SMT_NOT_SUPPORTED) |
| return -ENODEV; |
| |
| ret = lock_device_hotplug_sysfs(); |
| if (ret) |
| return ret; |
| |
| if (ctrlval != cpu_smt_control) { |
| switch (ctrlval) { |
| case CPU_SMT_ENABLED: |
| ret = cpuhp_smt_enable(); |
| break; |
| case CPU_SMT_DISABLED: |
| case CPU_SMT_FORCE_DISABLED: |
| ret = cpuhp_smt_disable(ctrlval); |
| break; |
| } |
| } |
| |
| unlock_device_hotplug(); |
| return ret ? ret : count; |
| } |
| static DEVICE_ATTR(control, 0644, show_smt_control, store_smt_control); |
| |
| static ssize_t |
| show_smt_active(struct device *dev, struct device_attribute *attr, char *buf) |
| { |
| bool active = topology_max_smt_threads() > 1; |
| |
| return snprintf(buf, PAGE_SIZE - 2, "%d\n", active); |
| } |
| static DEVICE_ATTR(active, 0444, show_smt_active, NULL); |
| |
| static struct attribute *cpuhp_smt_attrs[] = { |
| &dev_attr_control.attr, |
| &dev_attr_active.attr, |
| NULL |
| }; |
| |
| static const struct attribute_group cpuhp_smt_attr_group = { |
| .attrs = cpuhp_smt_attrs, |
| .name = "smt", |
| NULL |
| }; |
| |
| static int __init cpu_smt_state_init(void) |
| { |
| return sysfs_create_group(&cpu_subsys.dev_root->kobj, |
| &cpuhp_smt_attr_group); |
| } |
| |
| #else |
| static inline int cpu_smt_state_init(void) { return 0; } |
| #endif |
| |
| static int __init cpuhp_sysfs_init(void) |
| { |
| int cpu, ret; |
| |
| ret = cpu_smt_state_init(); |
| if (ret) |
| return ret; |
| |
| ret = sysfs_create_group(&cpu_subsys.dev_root->kobj, |
| &cpuhp_cpu_root_attr_group); |
| if (ret) |
| return ret; |
| |
| for_each_possible_cpu(cpu) { |
| struct device *dev = get_cpu_device(cpu); |
| |
| if (!dev) |
| continue; |
| ret = sysfs_create_group(&dev->kobj, &cpuhp_cpu_attr_group); |
| if (ret) |
| return ret; |
| } |
| return 0; |
| } |
| device_initcall(cpuhp_sysfs_init); |
| #endif |
| |
| /* |
| * cpu_bit_bitmap[] is a special, "compressed" data structure that |
| * represents all NR_CPUS bits binary values of 1<<nr. |
| * |
| * It is used by cpumask_of() to get a constant address to a CPU |
| * mask value that has a single bit set only. |
| */ |
| |
| /* cpu_bit_bitmap[0] is empty - so we can back into it */ |
| #define MASK_DECLARE_1(x) [x+1][0] = (1UL << (x)) |
| #define MASK_DECLARE_2(x) MASK_DECLARE_1(x), MASK_DECLARE_1(x+1) |
| #define MASK_DECLARE_4(x) MASK_DECLARE_2(x), MASK_DECLARE_2(x+2) |
| #define MASK_DECLARE_8(x) MASK_DECLARE_4(x), MASK_DECLARE_4(x+4) |
| |
| const unsigned long cpu_bit_bitmap[BITS_PER_LONG+1][BITS_TO_LONGS(NR_CPUS)] = { |
| |
| MASK_DECLARE_8(0), MASK_DECLARE_8(8), |
| MASK_DECLARE_8(16), MASK_DECLARE_8(24), |
| #if BITS_PER_LONG > 32 |
| MASK_DECLARE_8(32), MASK_DECLARE_8(40), |
| MASK_DECLARE_8(48), MASK_DECLARE_8(56), |
| #endif |
| }; |
| EXPORT_SYMBOL_GPL(cpu_bit_bitmap); |
| |
| const DECLARE_BITMAP(cpu_all_bits, NR_CPUS) = CPU_BITS_ALL; |
| EXPORT_SYMBOL(cpu_all_bits); |
| |
| #ifdef CONFIG_INIT_ALL_POSSIBLE |
| struct cpumask __cpu_possible_mask __read_mostly |
| = {CPU_BITS_ALL}; |
| #else |
| struct cpumask __cpu_possible_mask __read_mostly; |
| #endif |
| EXPORT_SYMBOL(__cpu_possible_mask); |
| |
| struct cpumask __cpu_online_mask __read_mostly; |
| EXPORT_SYMBOL(__cpu_online_mask); |
| |
| struct cpumask __cpu_present_mask __read_mostly; |
| EXPORT_SYMBOL(__cpu_present_mask); |
| |
| struct cpumask __cpu_active_mask __read_mostly; |
| EXPORT_SYMBOL(__cpu_active_mask); |
| |
| void init_cpu_present(const struct cpumask *src) |
| { |
| cpumask_copy(&__cpu_present_mask, src); |
| } |
| |
| void init_cpu_possible(const struct cpumask *src) |
| { |
| cpumask_copy(&__cpu_possible_mask, src); |
| } |
| |
| void init_cpu_online(const struct cpumask *src) |
| { |
| cpumask_copy(&__cpu_online_mask, src); |
| } |
| |
| /* |
| * Activate the first processor. |
| */ |
| void __init boot_cpu_init(void) |
| { |
| int cpu = smp_processor_id(); |
| |
| /* Mark the boot cpu "present", "online" etc for SMP and UP case */ |
| set_cpu_online(cpu, true); |
| set_cpu_active(cpu, true); |
| set_cpu_present(cpu, true); |
| set_cpu_possible(cpu, true); |
| |
| #ifdef CONFIG_SMP |
| __boot_cpu_id = cpu; |
| #endif |
| } |
| |
| /* |
| * Must be called _AFTER_ setting up the per_cpu areas |
| */ |
| void __init boot_cpu_hotplug_init(void) |
| { |
| #ifdef CONFIG_SMP |
| this_cpu_write(cpuhp_state.booted_once, true); |
| #endif |
| this_cpu_write(cpuhp_state.state, CPUHP_ONLINE); |
| } |
| |
| /* |
| * These are used for a global "mitigations=" cmdline option for toggling |
| * optional CPU mitigations. |
| */ |
| enum cpu_mitigations { |
| CPU_MITIGATIONS_OFF, |
| CPU_MITIGATIONS_AUTO, |
| CPU_MITIGATIONS_AUTO_NOSMT, |
| }; |
| |
| static enum cpu_mitigations cpu_mitigations __ro_after_init = |
| CPU_MITIGATIONS_AUTO; |
| |
| static int __init mitigations_parse_cmdline(char *arg) |
| { |
| if (!strcmp(arg, "off")) |
| cpu_mitigations = CPU_MITIGATIONS_OFF; |
| else if (!strcmp(arg, "auto")) |
| cpu_mitigations = CPU_MITIGATIONS_AUTO; |
| else if (!strcmp(arg, "auto,nosmt")) |
| cpu_mitigations = CPU_MITIGATIONS_AUTO_NOSMT; |
| else |
| pr_crit("Unsupported mitigations=%s, system may still be vulnerable\n", |
| arg); |
| |
| return 0; |
| } |
| early_param("mitigations", mitigations_parse_cmdline); |
| |
| /* mitigations=off */ |
| bool cpu_mitigations_off(void) |
| { |
| return cpu_mitigations == CPU_MITIGATIONS_OFF; |
| } |
| EXPORT_SYMBOL_GPL(cpu_mitigations_off); |
| |
| /* mitigations=auto,nosmt */ |
| bool cpu_mitigations_auto_nosmt(void) |
| { |
| return cpu_mitigations == CPU_MITIGATIONS_AUTO_NOSMT; |
| } |
| EXPORT_SYMBOL_GPL(cpu_mitigations_auto_nosmt); |