142 lines
4.0 KiB
C
142 lines
4.0 KiB
C
#ifndef _LINUX_STOP_MACHINE
|
|
#define _LINUX_STOP_MACHINE
|
|
|
|
#include <linux/cpu.h>
|
|
#include <linux/cpumask.h>
|
|
#include <linux/smp.h>
|
|
#include <linux/list.h>
|
|
|
|
/*
|
|
* stop_cpu[s]() is simplistic per-cpu maximum priority cpu
|
|
* monopolization mechanism. The caller can specify a non-sleeping
|
|
* function to be executed on a single or multiple cpus preempting all
|
|
* other processes and monopolizing those cpus until it finishes.
|
|
*
|
|
* Resources for this mechanism are preallocated when a cpu is brought
|
|
* up and requests are guaranteed to be served as long as the target
|
|
* cpus are online.
|
|
*/
|
|
typedef int (*cpu_stop_fn_t)(void *arg);
|
|
|
|
#ifdef CONFIG_SMP
|
|
|
|
struct cpu_stop_work {
|
|
struct list_head list; /* cpu_stopper->works */
|
|
cpu_stop_fn_t fn;
|
|
void *arg;
|
|
struct cpu_stop_done *done;
|
|
};
|
|
|
|
int stop_one_cpu(unsigned int cpu, cpu_stop_fn_t fn, void *arg);
|
|
int stop_two_cpus(unsigned int cpu1, unsigned int cpu2, cpu_stop_fn_t fn, void *arg);
|
|
void stop_one_cpu_nowait(unsigned int cpu, cpu_stop_fn_t fn, void *arg,
|
|
struct cpu_stop_work *work_buf);
|
|
int stop_cpus(const struct cpumask *cpumask, cpu_stop_fn_t fn, void *arg);
|
|
int try_stop_cpus(const struct cpumask *cpumask, cpu_stop_fn_t fn, void *arg);
|
|
void stop_machine_park(int cpu);
|
|
void stop_machine_unpark(int cpu);
|
|
|
|
#else /* CONFIG_SMP */
|
|
|
|
#include <linux/workqueue.h>
|
|
|
|
struct cpu_stop_work {
|
|
struct work_struct work;
|
|
cpu_stop_fn_t fn;
|
|
void *arg;
|
|
};
|
|
|
|
static inline int stop_one_cpu(unsigned int cpu, cpu_stop_fn_t fn, void *arg)
|
|
{
|
|
int ret = -ENOENT;
|
|
preempt_disable();
|
|
if (cpu == smp_processor_id())
|
|
ret = fn(arg);
|
|
preempt_enable();
|
|
return ret;
|
|
}
|
|
|
|
static void stop_one_cpu_nowait_workfn(struct work_struct *work)
|
|
{
|
|
struct cpu_stop_work *stwork =
|
|
container_of(work, struct cpu_stop_work, work);
|
|
preempt_disable();
|
|
stwork->fn(stwork->arg);
|
|
preempt_enable();
|
|
}
|
|
|
|
static inline void stop_one_cpu_nowait(unsigned int cpu,
|
|
cpu_stop_fn_t fn, void *arg,
|
|
struct cpu_stop_work *work_buf)
|
|
{
|
|
if (cpu == smp_processor_id()) {
|
|
INIT_WORK(&work_buf->work, stop_one_cpu_nowait_workfn);
|
|
work_buf->fn = fn;
|
|
work_buf->arg = arg;
|
|
schedule_work(&work_buf->work);
|
|
}
|
|
}
|
|
|
|
static inline int stop_cpus(const struct cpumask *cpumask,
|
|
cpu_stop_fn_t fn, void *arg)
|
|
{
|
|
if (cpumask_test_cpu(raw_smp_processor_id(), cpumask))
|
|
return stop_one_cpu(raw_smp_processor_id(), fn, arg);
|
|
return -ENOENT;
|
|
}
|
|
|
|
static inline int try_stop_cpus(const struct cpumask *cpumask,
|
|
cpu_stop_fn_t fn, void *arg)
|
|
{
|
|
return stop_cpus(cpumask, fn, arg);
|
|
}
|
|
|
|
#endif /* CONFIG_SMP */
|
|
|
|
/*
|
|
* stop_machine "Bogolock": stop the entire machine, disable
|
|
* interrupts. This is a very heavy lock, which is equivalent to
|
|
* grabbing every spinlock (and more). So the "read" side to such a
|
|
* lock is anything which disables preemption.
|
|
*/
|
|
#if defined(CONFIG_SMP) || defined(CONFIG_HOTPLUG_CPU)
|
|
|
|
/**
|
|
* stop_machine: freeze the machine on all CPUs and run this function
|
|
* @fn: the function to run
|
|
* @data: the data ptr for the @fn()
|
|
* @cpus: the cpus to run the @fn() on (NULL = any online cpu)
|
|
*
|
|
* Description: This causes a thread to be scheduled on every cpu,
|
|
* each of which disables interrupts. The result is that no one is
|
|
* holding a spinlock or inside any other preempt-disabled region when
|
|
* @fn() runs.
|
|
*
|
|
* This can be thought of as a very heavy write lock, equivalent to
|
|
* grabbing every spinlock in the kernel. */
|
|
int stop_machine(cpu_stop_fn_t fn, void *data, const struct cpumask *cpus);
|
|
|
|
int stop_machine_from_inactive_cpu(cpu_stop_fn_t fn, void *data,
|
|
const struct cpumask *cpus);
|
|
#else /* CONFIG_SMP || CONFIG_HOTPLUG_CPU */
|
|
|
|
static inline int stop_machine(cpu_stop_fn_t fn, void *data,
|
|
const struct cpumask *cpus)
|
|
{
|
|
unsigned long flags;
|
|
int ret;
|
|
local_irq_save(flags);
|
|
ret = fn(data);
|
|
local_irq_restore(flags);
|
|
return ret;
|
|
}
|
|
|
|
static inline int stop_machine_from_inactive_cpu(cpu_stop_fn_t fn, void *data,
|
|
const struct cpumask *cpus)
|
|
{
|
|
return stop_machine(fn, data, cpus);
|
|
}
|
|
|
|
#endif /* CONFIG_SMP || CONFIG_HOTPLUG_CPU */
|
|
#endif /* _LINUX_STOP_MACHINE */
|