1 #ifndef _LINUX_STOP_MACHINE
2 #define _LINUX_STOP_MACHINE
5 #include <linux/cpumask.h>
7 #include <linux/list.h>
10 * stop_cpu[s]() is simplistic per-cpu maximum priority cpu
11 * monopolization mechanism. The caller can specify a non-sleeping
12 * function to be executed on a single or multiple cpus preempting all
13 * other processes and monopolizing those cpus until it finishes.
15 * Resources for this mechanism are preallocated when a cpu is brought
16 * up and requests are guaranteed to be served as long as the target
19 typedef int (*cpu_stop_fn_t
)(void *arg
);
23 struct cpu_stop_work
{
24 struct list_head list
; /* cpu_stopper->works */
27 struct cpu_stop_done
*done
;
30 int stop_one_cpu(unsigned int cpu
, cpu_stop_fn_t fn
, void *arg
);
31 int stop_two_cpus(unsigned int cpu1
, unsigned int cpu2
, cpu_stop_fn_t fn
, void *arg
);
32 void stop_one_cpu_nowait(unsigned int cpu
, cpu_stop_fn_t fn
, void *arg
,
33 struct cpu_stop_work
*work_buf
);
34 int stop_cpus(const struct cpumask
*cpumask
, cpu_stop_fn_t fn
, void *arg
);
35 int try_stop_cpus(const struct cpumask
*cpumask
, cpu_stop_fn_t fn
, void *arg
);
36 void stop_machine_park(int cpu
);
38 #else /* CONFIG_SMP */
40 #include <linux/workqueue.h>
42 struct cpu_stop_work
{
43 struct work_struct work
;
48 static inline int stop_one_cpu(unsigned int cpu
, cpu_stop_fn_t fn
, void *arg
)
52 if (cpu
== smp_processor_id())
58 static void stop_one_cpu_nowait_workfn(struct work_struct
*work
)
60 struct cpu_stop_work
*stwork
=
61 container_of(work
, struct cpu_stop_work
, work
);
63 stwork
->fn(stwork
->arg
);
67 static inline void stop_one_cpu_nowait(unsigned int cpu
,
68 cpu_stop_fn_t fn
, void *arg
,
69 struct cpu_stop_work
*work_buf
)
71 if (cpu
== smp_processor_id()) {
72 INIT_WORK(&work_buf
->work
, stop_one_cpu_nowait_workfn
);
75 schedule_work(&work_buf
->work
);
79 static inline int stop_cpus(const struct cpumask
*cpumask
,
80 cpu_stop_fn_t fn
, void *arg
)
82 if (cpumask_test_cpu(raw_smp_processor_id(), cpumask
))
83 return stop_one_cpu(raw_smp_processor_id(), fn
, arg
);
87 static inline int try_stop_cpus(const struct cpumask
*cpumask
,
88 cpu_stop_fn_t fn
, void *arg
)
90 return stop_cpus(cpumask
, fn
, arg
);
93 #endif /* CONFIG_SMP */
96 * stop_machine "Bogolock": stop the entire machine, disable
97 * interrupts. This is a very heavy lock, which is equivalent to
98 * grabbing every spinlock (and more). So the "read" side to such a
99 * lock is anything which disables preemption.
101 #if defined(CONFIG_STOP_MACHINE) && defined(CONFIG_SMP)
104 * stop_machine: freeze the machine on all CPUs and run this function
105 * @fn: the function to run
106 * @data: the data ptr for the @fn()
107 * @cpus: the cpus to run the @fn() on (NULL = any online cpu)
109 * Description: This causes a thread to be scheduled on every cpu,
110 * each of which disables interrupts. The result is that no one is
111 * holding a spinlock or inside any other preempt-disabled region when
114 * This can be thought of as a very heavy write lock, equivalent to
115 * grabbing every spinlock in the kernel. */
116 int stop_machine(cpu_stop_fn_t fn
, void *data
, const struct cpumask
*cpus
);
118 int stop_machine_from_inactive_cpu(cpu_stop_fn_t fn
, void *data
,
119 const struct cpumask
*cpus
);
120 #else /* CONFIG_STOP_MACHINE && CONFIG_SMP */
122 static inline int stop_machine(cpu_stop_fn_t fn
, void *data
,
123 const struct cpumask
*cpus
)
127 local_irq_save(flags
);
129 local_irq_restore(flags
);
133 static inline int stop_machine_from_inactive_cpu(cpu_stop_fn_t fn
, void *data
,
134 const struct cpumask
*cpus
)
136 return stop_machine(fn
, data
, cpus
);
139 #endif /* CONFIG_STOP_MACHINE && CONFIG_SMP */
140 #endif /* _LINUX_STOP_MACHINE */