mirror of
https://github.com/AuxXxilium/linux_dsm_epyc7002.git
synced 2024-12-07 08:56:39 +07:00
1da177e4c3
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
194 lines
4.2 KiB
C
194 lines
4.2 KiB
C
/* 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.h>
|
|
#include <linux/unistd.h>
|
|
#include <linux/cpu.h>
|
|
#include <linux/module.h>
|
|
#include <linux/kthread.h>
|
|
#include <linux/stop_machine.h>
|
|
#include <asm/semaphore.h>
|
|
|
|
/* This protects CPUs going up and down... */
|
|
DECLARE_MUTEX(cpucontrol);
|
|
|
|
static struct notifier_block *cpu_chain;
|
|
|
|
/* Need to know about CPUs going up/down? */
|
|
int register_cpu_notifier(struct notifier_block *nb)
|
|
{
|
|
int ret;
|
|
|
|
if ((ret = down_interruptible(&cpucontrol)) != 0)
|
|
return ret;
|
|
ret = notifier_chain_register(&cpu_chain, nb);
|
|
up(&cpucontrol);
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL(register_cpu_notifier);
|
|
|
|
void unregister_cpu_notifier(struct notifier_block *nb)
|
|
{
|
|
down(&cpucontrol);
|
|
notifier_chain_unregister(&cpu_chain, nb);
|
|
up(&cpucontrol);
|
|
}
|
|
EXPORT_SYMBOL(unregister_cpu_notifier);
|
|
|
|
#ifdef CONFIG_HOTPLUG_CPU
|
|
static inline void check_for_tasks(int cpu)
|
|
{
|
|
struct task_struct *p;
|
|
|
|
write_lock_irq(&tasklist_lock);
|
|
for_each_process(p) {
|
|
if (task_cpu(p) == cpu &&
|
|
(!cputime_eq(p->utime, cputime_zero) ||
|
|
!cputime_eq(p->stime, cputime_zero)))
|
|
printk(KERN_WARNING "Task %s (pid = %d) is on cpu %d\
|
|
(state = %ld, flags = %lx) \n",
|
|
p->comm, p->pid, cpu, p->state, p->flags);
|
|
}
|
|
write_unlock_irq(&tasklist_lock);
|
|
}
|
|
|
|
/* Take this CPU down. */
|
|
static int take_cpu_down(void *unused)
|
|
{
|
|
int err;
|
|
|
|
/* Take offline: makes arch_cpu_down somewhat easier. */
|
|
cpu_clear(smp_processor_id(), cpu_online_map);
|
|
|
|
/* Ensure this CPU doesn't handle any more interrupts. */
|
|
err = __cpu_disable();
|
|
if (err < 0)
|
|
cpu_set(smp_processor_id(), cpu_online_map);
|
|
else
|
|
/* Force idle task to run as soon as we yield: it should
|
|
immediately notice cpu is offline and die quickly. */
|
|
sched_idle_next();
|
|
|
|
return err;
|
|
}
|
|
|
|
int cpu_down(unsigned int cpu)
|
|
{
|
|
int err;
|
|
struct task_struct *p;
|
|
cpumask_t old_allowed, tmp;
|
|
|
|
if ((err = lock_cpu_hotplug_interruptible()) != 0)
|
|
return err;
|
|
|
|
if (num_online_cpus() == 1) {
|
|
err = -EBUSY;
|
|
goto out;
|
|
}
|
|
|
|
if (!cpu_online(cpu)) {
|
|
err = -EINVAL;
|
|
goto out;
|
|
}
|
|
|
|
err = notifier_call_chain(&cpu_chain, CPU_DOWN_PREPARE,
|
|
(void *)(long)cpu);
|
|
if (err == NOTIFY_BAD) {
|
|
printk("%s: attempt to take down CPU %u failed\n",
|
|
__FUNCTION__, cpu);
|
|
err = -EINVAL;
|
|
goto out;
|
|
}
|
|
|
|
/* Ensure that we are not runnable on dying cpu */
|
|
old_allowed = current->cpus_allowed;
|
|
tmp = CPU_MASK_ALL;
|
|
cpu_clear(cpu, tmp);
|
|
set_cpus_allowed(current, tmp);
|
|
|
|
p = __stop_machine_run(take_cpu_down, NULL, cpu);
|
|
if (IS_ERR(p)) {
|
|
/* CPU didn't die: tell everyone. Can't complain. */
|
|
if (notifier_call_chain(&cpu_chain, CPU_DOWN_FAILED,
|
|
(void *)(long)cpu) == NOTIFY_BAD)
|
|
BUG();
|
|
|
|
err = PTR_ERR(p);
|
|
goto out_allowed;
|
|
}
|
|
|
|
if (cpu_online(cpu))
|
|
goto out_thread;
|
|
|
|
/* Wait for it to sleep (leaving idle task). */
|
|
while (!idle_cpu(cpu))
|
|
yield();
|
|
|
|
/* This actually kills the CPU. */
|
|
__cpu_die(cpu);
|
|
|
|
/* Move it here so it can run. */
|
|
kthread_bind(p, get_cpu());
|
|
put_cpu();
|
|
|
|
/* CPU is completely dead: tell everyone. Too late to complain. */
|
|
if (notifier_call_chain(&cpu_chain, CPU_DEAD, (void *)(long)cpu)
|
|
== NOTIFY_BAD)
|
|
BUG();
|
|
|
|
check_for_tasks(cpu);
|
|
|
|
out_thread:
|
|
err = kthread_stop(p);
|
|
out_allowed:
|
|
set_cpus_allowed(current, old_allowed);
|
|
out:
|
|
unlock_cpu_hotplug();
|
|
return err;
|
|
}
|
|
#endif /*CONFIG_HOTPLUG_CPU*/
|
|
|
|
int __devinit cpu_up(unsigned int cpu)
|
|
{
|
|
int ret;
|
|
void *hcpu = (void *)(long)cpu;
|
|
|
|
if ((ret = down_interruptible(&cpucontrol)) != 0)
|
|
return ret;
|
|
|
|
if (cpu_online(cpu) || !cpu_present(cpu)) {
|
|
ret = -EINVAL;
|
|
goto out;
|
|
}
|
|
ret = notifier_call_chain(&cpu_chain, CPU_UP_PREPARE, hcpu);
|
|
if (ret == NOTIFY_BAD) {
|
|
printk("%s: attempt to bring up CPU %u failed\n",
|
|
__FUNCTION__, cpu);
|
|
ret = -EINVAL;
|
|
goto out_notify;
|
|
}
|
|
|
|
/* Arch-specific enabling code. */
|
|
ret = __cpu_up(cpu);
|
|
if (ret != 0)
|
|
goto out_notify;
|
|
if (!cpu_online(cpu))
|
|
BUG();
|
|
|
|
/* Now call notifier in preparation. */
|
|
notifier_call_chain(&cpu_chain, CPU_ONLINE, hcpu);
|
|
|
|
out_notify:
|
|
if (ret != 0)
|
|
notifier_call_chain(&cpu_chain, CPU_UP_CANCELED, hcpu);
|
|
out:
|
|
up(&cpucontrol);
|
|
return ret;
|
|
}
|