^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1) // SPDX-License-Identifier: GPL-2.0-only
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3) * Common SMP CPU bringup/teardown functions
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 4) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 5) #include <linux/cpu.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 6) #include <linux/err.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 7) #include <linux/smp.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 8) #include <linux/delay.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 9) #include <linux/init.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 10) #include <linux/list.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 11) #include <linux/slab.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 12) #include <linux/sched.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 13) #include <linux/sched/task.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 14) #include <linux/export.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 15) #include <linux/percpu.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 16) #include <linux/kthread.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 17) #include <linux/smpboot.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 18)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 19) #include "smpboot.h"
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 20)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 21) #ifdef CONFIG_SMP
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 22)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 23) #ifdef CONFIG_GENERIC_SMP_IDLE_THREAD
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 24) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 25) * For the hotplug case we keep the task structs around and reuse
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 26) * them.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 27) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 28) static DEFINE_PER_CPU(struct task_struct *, idle_threads);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 29)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 30) struct task_struct *idle_thread_get(unsigned int cpu)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 31) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 32) struct task_struct *tsk = per_cpu(idle_threads, cpu);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 33)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 34) if (!tsk)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 35) return ERR_PTR(-ENOMEM);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 36) return tsk;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 37) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 38)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 39) void __init idle_thread_set_boot_cpu(void)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 40) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 41) per_cpu(idle_threads, smp_processor_id()) = current;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 42) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 43)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 44) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 45) * idle_init - Initialize the idle thread for a cpu
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 46) * @cpu: The cpu for which the idle thread should be initialized
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 47) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 48) * Creates the thread if it does not exist.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 49) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 50) static inline void idle_init(unsigned int cpu)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 51) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 52) struct task_struct *tsk = per_cpu(idle_threads, cpu);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 53)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 54) if (!tsk) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 55) tsk = fork_idle(cpu);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 56) if (IS_ERR(tsk))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 57) pr_err("SMP: fork_idle() failed for CPU %u\n", cpu);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 58) else
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 59) per_cpu(idle_threads, cpu) = tsk;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 60) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 61) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 62)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 63) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 64) * idle_threads_init - Initialize idle threads for all cpus
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 65) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 66) void __init idle_threads_init(void)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 67) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 68) unsigned int cpu, boot_cpu;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 69)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 70) boot_cpu = smp_processor_id();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 71)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 72) for_each_possible_cpu(cpu) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 73) if (cpu != boot_cpu)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 74) idle_init(cpu);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 75) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 76) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 77) #endif
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 78)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 79) #endif /* #ifdef CONFIG_SMP */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 80)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 81) static LIST_HEAD(hotplug_threads);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 82) static DEFINE_MUTEX(smpboot_threads_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 83)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 84) struct smpboot_thread_data {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 85) unsigned int cpu;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 86) unsigned int status;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 87) struct smp_hotplug_thread *ht;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 88) };
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 89)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 90) enum {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 91) HP_THREAD_NONE = 0,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 92) HP_THREAD_ACTIVE,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 93) HP_THREAD_PARKED,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 94) };
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 95)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 96) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 97) * smpboot_thread_fn - percpu hotplug thread loop function
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 98) * @data: thread data pointer
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 99) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 100) * Checks for thread stop and park conditions. Calls the necessary
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 101) * setup, cleanup, park and unpark functions for the registered
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 102) * thread.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 103) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 104) * Returns 1 when the thread should exit, 0 otherwise.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 105) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 106) static int smpboot_thread_fn(void *data)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 107) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 108) struct smpboot_thread_data *td = data;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 109) struct smp_hotplug_thread *ht = td->ht;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 110)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 111) while (1) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 112) set_current_state(TASK_INTERRUPTIBLE);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 113) preempt_disable();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 114) if (kthread_should_stop()) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 115) __set_current_state(TASK_RUNNING);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 116) preempt_enable();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 117) /* cleanup must mirror setup */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 118) if (ht->cleanup && td->status != HP_THREAD_NONE)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 119) ht->cleanup(td->cpu, cpu_online(td->cpu));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 120) kfree(td);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 121) return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 122) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 123)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 124) if (kthread_should_park()) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 125) __set_current_state(TASK_RUNNING);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 126) preempt_enable();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 127) if (ht->park && td->status == HP_THREAD_ACTIVE) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 128) BUG_ON(td->cpu != smp_processor_id());
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 129) ht->park(td->cpu);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 130) td->status = HP_THREAD_PARKED;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 131) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 132) kthread_parkme();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 133) /* We might have been woken for stop */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 134) continue;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 135) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 136)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 137) BUG_ON(td->cpu != smp_processor_id());
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 138)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 139) /* Check for state change setup */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 140) switch (td->status) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 141) case HP_THREAD_NONE:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 142) __set_current_state(TASK_RUNNING);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 143) preempt_enable();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 144) if (ht->setup)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 145) ht->setup(td->cpu);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 146) td->status = HP_THREAD_ACTIVE;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 147) continue;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 148)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 149) case HP_THREAD_PARKED:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 150) __set_current_state(TASK_RUNNING);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 151) preempt_enable();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 152) if (ht->unpark)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 153) ht->unpark(td->cpu);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 154) td->status = HP_THREAD_ACTIVE;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 155) continue;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 156) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 157)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 158) if (!ht->thread_should_run(td->cpu)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 159) preempt_enable_no_resched();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 160) schedule();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 161) } else {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 162) __set_current_state(TASK_RUNNING);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 163) preempt_enable();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 164) ht->thread_fn(td->cpu);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 165) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 166) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 167) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 168)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 169) static int
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 170) __smpboot_create_thread(struct smp_hotplug_thread *ht, unsigned int cpu)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 171) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 172) struct task_struct *tsk = *per_cpu_ptr(ht->store, cpu);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 173) struct smpboot_thread_data *td;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 174)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 175) if (tsk)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 176) return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 177)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 178) td = kzalloc_node(sizeof(*td), GFP_KERNEL, cpu_to_node(cpu));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 179) if (!td)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 180) return -ENOMEM;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 181) td->cpu = cpu;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 182) td->ht = ht;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 183)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 184) tsk = kthread_create_on_cpu(smpboot_thread_fn, td, cpu,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 185) ht->thread_comm);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 186) if (IS_ERR(tsk)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 187) kfree(td);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 188) return PTR_ERR(tsk);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 189) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 190) kthread_set_per_cpu(tsk, cpu);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 191) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 192) * Park the thread so that it could start right on the CPU
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 193) * when it is available.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 194) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 195) kthread_park(tsk);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 196) get_task_struct(tsk);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 197) *per_cpu_ptr(ht->store, cpu) = tsk;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 198) if (ht->create) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 199) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 200) * Make sure that the task has actually scheduled out
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 201) * into park position, before calling the create
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 202) * callback. At least the migration thread callback
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 203) * requires that the task is off the runqueue.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 204) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 205) if (!wait_task_inactive(tsk, TASK_PARKED))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 206) WARN_ON(1);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 207) else
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 208) ht->create(cpu);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 209) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 210) return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 211) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 212)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 213) int smpboot_create_threads(unsigned int cpu)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 214) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 215) struct smp_hotplug_thread *cur;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 216) int ret = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 217)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 218) mutex_lock(&smpboot_threads_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 219) list_for_each_entry(cur, &hotplug_threads, list) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 220) ret = __smpboot_create_thread(cur, cpu);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 221) if (ret)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 222) break;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 223) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 224) mutex_unlock(&smpboot_threads_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 225) return ret;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 226) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 227)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 228) static void smpboot_unpark_thread(struct smp_hotplug_thread *ht, unsigned int cpu)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 229) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 230) struct task_struct *tsk = *per_cpu_ptr(ht->store, cpu);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 231)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 232) if (!ht->selfparking)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 233) kthread_unpark(tsk);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 234) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 235)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 236) int smpboot_unpark_threads(unsigned int cpu)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 237) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 238) struct smp_hotplug_thread *cur;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 239)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 240) mutex_lock(&smpboot_threads_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 241) list_for_each_entry(cur, &hotplug_threads, list)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 242) smpboot_unpark_thread(cur, cpu);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 243) mutex_unlock(&smpboot_threads_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 244) return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 245) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 246)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 247) static void smpboot_park_thread(struct smp_hotplug_thread *ht, unsigned int cpu)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 248) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 249) struct task_struct *tsk = *per_cpu_ptr(ht->store, cpu);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 250)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 251) if (tsk && !ht->selfparking)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 252) kthread_park(tsk);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 253) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 254)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 255) int smpboot_park_threads(unsigned int cpu)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 256) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 257) struct smp_hotplug_thread *cur;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 258)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 259) mutex_lock(&smpboot_threads_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 260) list_for_each_entry_reverse(cur, &hotplug_threads, list)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 261) smpboot_park_thread(cur, cpu);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 262) mutex_unlock(&smpboot_threads_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 263) return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 264) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 265)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 266) static void smpboot_destroy_threads(struct smp_hotplug_thread *ht)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 267) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 268) unsigned int cpu;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 269)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 270) /* We need to destroy also the parked threads of offline cpus */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 271) for_each_possible_cpu(cpu) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 272) struct task_struct *tsk = *per_cpu_ptr(ht->store, cpu);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 273)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 274) if (tsk) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 275) kthread_stop(tsk);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 276) put_task_struct(tsk);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 277) *per_cpu_ptr(ht->store, cpu) = NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 278) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 279) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 280) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 281)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 282) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 283) * smpboot_register_percpu_thread - Register a per_cpu thread related
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 284) * to hotplug
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 285) * @plug_thread: Hotplug thread descriptor
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 286) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 287) * Creates and starts the threads on all online cpus.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 288) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 289) int smpboot_register_percpu_thread(struct smp_hotplug_thread *plug_thread)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 290) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 291) unsigned int cpu;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 292) int ret = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 293)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 294) get_online_cpus();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 295) mutex_lock(&smpboot_threads_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 296) for_each_online_cpu(cpu) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 297) ret = __smpboot_create_thread(plug_thread, cpu);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 298) if (ret) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 299) smpboot_destroy_threads(plug_thread);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 300) goto out;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 301) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 302) smpboot_unpark_thread(plug_thread, cpu);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 303) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 304) list_add(&plug_thread->list, &hotplug_threads);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 305) out:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 306) mutex_unlock(&smpboot_threads_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 307) put_online_cpus();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 308) return ret;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 309) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 310) EXPORT_SYMBOL_GPL(smpboot_register_percpu_thread);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 311)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 312) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 313) * smpboot_unregister_percpu_thread - Unregister a per_cpu thread related to hotplug
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 314) * @plug_thread: Hotplug thread descriptor
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 315) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 316) * Stops all threads on all possible cpus.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 317) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 318) void smpboot_unregister_percpu_thread(struct smp_hotplug_thread *plug_thread)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 319) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 320) get_online_cpus();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 321) mutex_lock(&smpboot_threads_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 322) list_del(&plug_thread->list);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 323) smpboot_destroy_threads(plug_thread);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 324) mutex_unlock(&smpboot_threads_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 325) put_online_cpus();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 326) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 327) EXPORT_SYMBOL_GPL(smpboot_unregister_percpu_thread);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 328)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 329) static DEFINE_PER_CPU(atomic_t, cpu_hotplug_state) = ATOMIC_INIT(CPU_POST_DEAD);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 330)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 331) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 332) * Called to poll specified CPU's state, for example, when waiting for
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 333) * a CPU to come online.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 334) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 335) int cpu_report_state(int cpu)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 336) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 337) return atomic_read(&per_cpu(cpu_hotplug_state, cpu));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 338) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 339)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 340) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 341) * If CPU has died properly, set its state to CPU_UP_PREPARE and
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 342) * return success. Otherwise, return -EBUSY if the CPU died after
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 343) * cpu_wait_death() timed out. And yet otherwise again, return -EAGAIN
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 344) * if cpu_wait_death() timed out and the CPU still hasn't gotten around
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 345) * to dying. In the latter two cases, the CPU might not be set up
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 346) * properly, but it is up to the arch-specific code to decide.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 347) * Finally, -EIO indicates an unanticipated problem.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 348) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 349) * Note that it is permissible to omit this call entirely, as is
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 350) * done in architectures that do no CPU-hotplug error checking.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 351) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 352) int cpu_check_up_prepare(int cpu)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 353) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 354) if (!IS_ENABLED(CONFIG_HOTPLUG_CPU)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 355) atomic_set(&per_cpu(cpu_hotplug_state, cpu), CPU_UP_PREPARE);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 356) return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 357) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 358)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 359) switch (atomic_read(&per_cpu(cpu_hotplug_state, cpu))) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 360)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 361) case CPU_POST_DEAD:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 362)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 363) /* The CPU died properly, so just start it up again. */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 364) atomic_set(&per_cpu(cpu_hotplug_state, cpu), CPU_UP_PREPARE);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 365) return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 366)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 367) case CPU_DEAD_FROZEN:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 368)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 369) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 370) * Timeout during CPU death, so let caller know.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 371) * The outgoing CPU completed its processing, but after
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 372) * cpu_wait_death() timed out and reported the error. The
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 373) * caller is free to proceed, in which case the state
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 374) * will be reset properly by cpu_set_state_online().
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 375) * Proceeding despite this -EBUSY return makes sense
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 376) * for systems where the outgoing CPUs take themselves
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 377) * offline, with no post-death manipulation required from
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 378) * a surviving CPU.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 379) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 380) return -EBUSY;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 381)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 382) case CPU_BROKEN:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 383)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 384) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 385) * The most likely reason we got here is that there was
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 386) * a timeout during CPU death, and the outgoing CPU never
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 387) * did complete its processing. This could happen on
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 388) * a virtualized system if the outgoing VCPU gets preempted
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 389) * for more than five seconds, and the user attempts to
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 390) * immediately online that same CPU. Trying again later
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 391) * might return -EBUSY above, hence -EAGAIN.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 392) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 393) return -EAGAIN;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 394)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 395) default:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 396)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 397) /* Should not happen. Famous last words. */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 398) return -EIO;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 399) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 400) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 401)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 402) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 403) * Mark the specified CPU online.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 404) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 405) * Note that it is permissible to omit this call entirely, as is
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 406) * done in architectures that do no CPU-hotplug error checking.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 407) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 408) void cpu_set_state_online(int cpu)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 409) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 410) (void)atomic_xchg(&per_cpu(cpu_hotplug_state, cpu), CPU_ONLINE);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 411) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 412)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 413) #ifdef CONFIG_HOTPLUG_CPU
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 414)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 415) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 416) * Wait for the specified CPU to exit the idle loop and die.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 417) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 418) bool cpu_wait_death(unsigned int cpu, int seconds)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 419) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 420) int jf_left = seconds * HZ;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 421) int oldstate;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 422) bool ret = true;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 423) int sleep_jf = 1;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 424)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 425) might_sleep();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 426)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 427) /* The outgoing CPU will normally get done quite quickly. */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 428) if (atomic_read(&per_cpu(cpu_hotplug_state, cpu)) == CPU_DEAD)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 429) goto update_state;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 430) udelay(5);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 431)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 432) /* But if the outgoing CPU dawdles, wait increasingly long times. */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 433) while (atomic_read(&per_cpu(cpu_hotplug_state, cpu)) != CPU_DEAD) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 434) schedule_timeout_uninterruptible(sleep_jf);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 435) jf_left -= sleep_jf;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 436) if (jf_left <= 0)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 437) break;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 438) sleep_jf = DIV_ROUND_UP(sleep_jf * 11, 10);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 439) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 440) update_state:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 441) oldstate = atomic_read(&per_cpu(cpu_hotplug_state, cpu));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 442) if (oldstate == CPU_DEAD) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 443) /* Outgoing CPU died normally, update state. */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 444) smp_mb(); /* atomic_read() before update. */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 445) atomic_set(&per_cpu(cpu_hotplug_state, cpu), CPU_POST_DEAD);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 446) } else {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 447) /* Outgoing CPU still hasn't died, set state accordingly. */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 448) if (atomic_cmpxchg(&per_cpu(cpu_hotplug_state, cpu),
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 449) oldstate, CPU_BROKEN) != oldstate)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 450) goto update_state;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 451) ret = false;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 452) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 453) return ret;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 454) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 455)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 456) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 457) * Called by the outgoing CPU to report its successful death. Return
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 458) * false if this report follows the surviving CPU's timing out.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 459) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 460) * A separate "CPU_DEAD_FROZEN" is used when the surviving CPU
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 461) * timed out. This approach allows architectures to omit calls to
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 462) * cpu_check_up_prepare() and cpu_set_state_online() without defeating
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 463) * the next cpu_wait_death()'s polling loop.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 464) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 465) bool cpu_report_death(void)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 466) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 467) int oldstate;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 468) int newstate;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 469) int cpu = smp_processor_id();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 470)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 471) do {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 472) oldstate = atomic_read(&per_cpu(cpu_hotplug_state, cpu));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 473) if (oldstate != CPU_BROKEN)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 474) newstate = CPU_DEAD;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 475) else
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 476) newstate = CPU_DEAD_FROZEN;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 477) } while (atomic_cmpxchg(&per_cpu(cpu_hotplug_state, cpu),
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 478) oldstate, newstate) != oldstate);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 479) return newstate == CPU_DEAD;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 480) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 481)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 482) #endif /* #ifdef CONFIG_HOTPLUG_CPU */
Orange Pi5 kernel
Deprecated Linux kernel 5.10.110 for OrangePi 5/5B/5+ boards
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