blob: e0f2da25d751a50e3ca52e7c3d044b9765cd53dc [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001#ifndef _LINUX_STOP_MACHINE
2#define _LINUX_STOP_MACHINE
Tejun Heo1142d812010-05-06 18:49:20 +02003
Linus Torvalds1da177e2005-04-16 15:20:36 -07004#include <linux/cpu.h>
Rusty Russelleeec4fa2008-07-28 12:16:30 -05005#include <linux/cpumask.h>
Tejun Heo1142d812010-05-06 18:49:20 +02006#include <linux/list.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -07007#include <asm/system.h>
8
Tejun Heo1142d812010-05-06 18:49:20 +02009/*
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.
14 *
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
17 * cpus are online.
18 */
Tejun Heo1142d812010-05-06 18:49:20 +020019typedef int (*cpu_stop_fn_t)(void *arg);
20
Tejun Heobbf1bb32010-05-08 16:20:53 +020021#ifdef CONFIG_SMP
22
Tejun Heo1142d812010-05-06 18:49:20 +020023struct cpu_stop_work {
24 struct list_head list; /* cpu_stopper->works */
25 cpu_stop_fn_t fn;
26 void *arg;
27 struct cpu_stop_done *done;
28};
29
Suresh Siddha6d3321e2011-06-23 11:19:26 -070030extern struct mutex stop_cpus_mutex;
31
Tejun Heo1142d812010-05-06 18:49:20 +020032int stop_one_cpu(unsigned int cpu, cpu_stop_fn_t fn, void *arg);
33void stop_one_cpu_nowait(unsigned int cpu, cpu_stop_fn_t fn, void *arg,
34 struct cpu_stop_work *work_buf);
35int stop_cpus(const struct cpumask *cpumask, cpu_stop_fn_t fn, void *arg);
36int try_stop_cpus(const struct cpumask *cpumask, cpu_stop_fn_t fn, void *arg);
37
Tejun Heobbf1bb32010-05-08 16:20:53 +020038#else /* CONFIG_SMP */
39
40#include <linux/workqueue.h>
41
42struct cpu_stop_work {
43 struct work_struct work;
44 cpu_stop_fn_t fn;
45 void *arg;
46};
47
48static inline int stop_one_cpu(unsigned int cpu, cpu_stop_fn_t fn, void *arg)
49{
50 int ret = -ENOENT;
51 preempt_disable();
52 if (cpu == smp_processor_id())
53 ret = fn(arg);
54 preempt_enable();
55 return ret;
56}
57
58static void stop_one_cpu_nowait_workfn(struct work_struct *work)
59{
60 struct cpu_stop_work *stwork =
61 container_of(work, struct cpu_stop_work, work);
62 preempt_disable();
63 stwork->fn(stwork->arg);
64 preempt_enable();
65}
66
67static inline void stop_one_cpu_nowait(unsigned int cpu,
68 cpu_stop_fn_t fn, void *arg,
69 struct cpu_stop_work *work_buf)
70{
71 if (cpu == smp_processor_id()) {
72 INIT_WORK(&work_buf->work, stop_one_cpu_nowait_workfn);
73 work_buf->fn = fn;
74 work_buf->arg = arg;
75 schedule_work(&work_buf->work);
76 }
77}
78
79static inline int stop_cpus(const struct cpumask *cpumask,
80 cpu_stop_fn_t fn, void *arg)
81{
82 if (cpumask_test_cpu(raw_smp_processor_id(), cpumask))
83 return stop_one_cpu(raw_smp_processor_id(), fn, arg);
84 return -ENOENT;
85}
86
87static inline int try_stop_cpus(const struct cpumask *cpumask,
88 cpu_stop_fn_t fn, void *arg)
89{
90 return stop_cpus(cpumask, fn, arg);
91}
92
93#endif /* CONFIG_SMP */
94
Tejun Heo1142d812010-05-06 18:49:20 +020095/*
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 preeempt.
100 */
Tejun Heobbf1bb32010-05-08 16:20:53 +0200101#if defined(CONFIG_STOP_MACHINE) && defined(CONFIG_SMP)
Tejun Heo1142d812010-05-06 18:49:20 +0200102
Linus Torvalds1da177e2005-04-16 15:20:36 -0700103/**
Rusty Russelleeec4fa2008-07-28 12:16:30 -0500104 * stop_machine: freeze the machine on all CPUs and run this function
Linus Torvalds1da177e2005-04-16 15:20:36 -0700105 * @fn: the function to run
106 * @data: the data ptr for the @fn()
Rusty Russelleeec4fa2008-07-28 12:16:30 -0500107 * @cpus: the cpus to run the @fn() on (NULL = any online cpu)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700108 *
Rusty Russellffdb5972008-07-28 12:16:28 -0500109 * Description: This causes a thread to be scheduled on every cpu,
Lucas De Marchi25985ed2011-03-30 22:57:33 -0300110 * each of which disables interrupts. The result is that no one is
Rusty Russellffdb5972008-07-28 12:16:28 -0500111 * holding a spinlock or inside any other preempt-disabled region when
112 * @fn() runs.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700113 *
114 * This can be thought of as a very heavy write lock, equivalent to
115 * grabbing every spinlock in the kernel. */
Rusty Russell41c7bb92009-01-01 10:12:28 +1030116int stop_machine(int (*fn)(void *), void *data, const struct cpumask *cpus);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700117
118/**
Rusty Russelleeec4fa2008-07-28 12:16:30 -0500119 * __stop_machine: freeze the machine on all CPUs and run this function
Linus Torvalds1da177e2005-04-16 15:20:36 -0700120 * @fn: the function to run
121 * @data: the data ptr for the @fn
Rusty Russelleeec4fa2008-07-28 12:16:30 -0500122 * @cpus: the cpus to run the @fn() on (NULL = any online cpu)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700123 *
Rusty Russellffdb5972008-07-28 12:16:28 -0500124 * Description: This is a special version of the above, which assumes cpus
125 * won't come or go while it's being called. Used by hotplug cpu.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700126 */
Rusty Russell41c7bb92009-01-01 10:12:28 +1030127int __stop_machine(int (*fn)(void *), void *data, const struct cpumask *cpus);
Heiko Carstens9ea09af2008-12-22 12:36:30 +0100128
Tejun Heof740e6cd2011-06-23 11:19:28 -0700129int stop_machine_from_inactive_cpu(int (*fn)(void *), void *data,
130 const struct cpumask *cpus);
131
Tejun Heobbf1bb32010-05-08 16:20:53 +0200132#else /* CONFIG_STOP_MACHINE && CONFIG_SMP */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700133
Masami Hiramatsu087a4eb2010-10-14 12:10:30 +0900134static inline int __stop_machine(int (*fn)(void *), void *data,
135 const struct cpumask *cpus)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700136{
Tejun Heof740e6cd2011-06-23 11:19:28 -0700137 unsigned long flags;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700138 int ret;
Tejun Heof740e6cd2011-06-23 11:19:28 -0700139 local_irq_save(flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700140 ret = fn(data);
Tejun Heof740e6cd2011-06-23 11:19:28 -0700141 local_irq_restore(flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700142 return ret;
143}
Heiko Carstens9ea09af2008-12-22 12:36:30 +0100144
Masami Hiramatsu087a4eb2010-10-14 12:10:30 +0900145static inline int stop_machine(int (*fn)(void *), void *data,
146 const struct cpumask *cpus)
147{
148 return __stop_machine(fn, data, cpus);
149}
150
Tejun Heof740e6cd2011-06-23 11:19:28 -0700151static inline int stop_machine_from_inactive_cpu(int (*fn)(void *), void *data,
152 const struct cpumask *cpus)
153{
154 return __stop_machine(fn, data, cpus);
155}
156
Tejun Heobbf1bb32010-05-08 16:20:53 +0200157#endif /* CONFIG_STOP_MACHINE && CONFIG_SMP */
158#endif /* _LINUX_STOP_MACHINE */