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1da177e4 LT |
1 | #ifndef _LINUX_STOP_MACHINE |
2 | #define _LINUX_STOP_MACHINE | |
1142d810 | 3 | |
1da177e4 | 4 | #include <linux/cpu.h> |
eeec4fad | 5 | #include <linux/cpumask.h> |
1142d810 | 6 | #include <linux/list.h> |
1da177e4 LT |
7 | #include <asm/system.h> |
8 | ||
9 | #if defined(CONFIG_STOP_MACHINE) && defined(CONFIG_SMP) | |
5c2aed62 | 10 | |
1142d810 TH |
11 | /* |
12 | * stop_cpu[s]() is simplistic per-cpu maximum priority cpu | |
13 | * monopolization mechanism. The caller can specify a non-sleeping | |
14 | * function to be executed on a single or multiple cpus preempting all | |
15 | * other processes and monopolizing those cpus until it finishes. | |
16 | * | |
17 | * Resources for this mechanism are preallocated when a cpu is brought | |
18 | * up and requests are guaranteed to be served as long as the target | |
19 | * cpus are online. | |
20 | */ | |
21 | ||
22 | typedef int (*cpu_stop_fn_t)(void *arg); | |
23 | ||
24 | struct cpu_stop_work { | |
25 | struct list_head list; /* cpu_stopper->works */ | |
26 | cpu_stop_fn_t fn; | |
27 | void *arg; | |
28 | struct cpu_stop_done *done; | |
29 | }; | |
30 | ||
31 | int stop_one_cpu(unsigned int cpu, 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 | ||
37 | /* | |
38 | * stop_machine "Bogolock": stop the entire machine, disable | |
39 | * interrupts. This is a very heavy lock, which is equivalent to | |
40 | * grabbing every spinlock (and more). So the "read" side to such a | |
41 | * lock is anything which disables preeempt. | |
42 | */ | |
43 | ||
1da177e4 | 44 | /** |
eeec4fad | 45 | * stop_machine: freeze the machine on all CPUs and run this function |
1da177e4 LT |
46 | * @fn: the function to run |
47 | * @data: the data ptr for the @fn() | |
eeec4fad | 48 | * @cpus: the cpus to run the @fn() on (NULL = any online cpu) |
1da177e4 | 49 | * |
ffdb5976 RR |
50 | * Description: This causes a thread to be scheduled on every cpu, |
51 | * each of which disables interrupts. The result is that noone is | |
52 | * holding a spinlock or inside any other preempt-disabled region when | |
53 | * @fn() runs. | |
1da177e4 LT |
54 | * |
55 | * This can be thought of as a very heavy write lock, equivalent to | |
56 | * grabbing every spinlock in the kernel. */ | |
41c7bb95 | 57 | int stop_machine(int (*fn)(void *), void *data, const struct cpumask *cpus); |
1da177e4 LT |
58 | |
59 | /** | |
eeec4fad | 60 | * __stop_machine: freeze the machine on all CPUs and run this function |
1da177e4 LT |
61 | * @fn: the function to run |
62 | * @data: the data ptr for the @fn | |
eeec4fad | 63 | * @cpus: the cpus to run the @fn() on (NULL = any online cpu) |
1da177e4 | 64 | * |
ffdb5976 RR |
65 | * Description: This is a special version of the above, which assumes cpus |
66 | * won't come or go while it's being called. Used by hotplug cpu. | |
1da177e4 | 67 | */ |
41c7bb95 | 68 | int __stop_machine(int (*fn)(void *), void *data, const struct cpumask *cpus); |
9ea09af3 HC |
69 | |
70 | /** | |
71 | * stop_machine_create: create all stop_machine threads | |
72 | * | |
73 | * Description: This causes all stop_machine threads to be created before | |
74 | * stop_machine actually gets called. This can be used by subsystems that | |
75 | * need a non failing stop_machine infrastructure. | |
76 | */ | |
77 | int stop_machine_create(void); | |
78 | ||
79 | /** | |
80 | * stop_machine_destroy: destroy all stop_machine threads | |
81 | * | |
82 | * Description: This causes all stop_machine threads which were created with | |
83 | * stop_machine_create to be destroyed again. | |
84 | */ | |
85 | void stop_machine_destroy(void); | |
86 | ||
1da177e4 LT |
87 | #else |
88 | ||
eeec4fad | 89 | static inline int stop_machine(int (*fn)(void *), void *data, |
41c7bb95 | 90 | const struct cpumask *cpus) |
1da177e4 LT |
91 | { |
92 | int ret; | |
93 | local_irq_disable(); | |
94 | ret = fn(data); | |
95 | local_irq_enable(); | |
96 | return ret; | |
97 | } | |
9ea09af3 HC |
98 | |
99 | static inline int stop_machine_create(void) { return 0; } | |
100 | static inline void stop_machine_destroy(void) { } | |
101 | ||
1da177e4 LT |
102 | #endif /* CONFIG_SMP */ |
103 | #endif /* _LINUX_STOP_MACHINE */ |