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b2441318 | 1 | /* SPDX-License-Identifier: GPL-2.0 */ |
1da177e4 LT |
2 | #ifndef _LINUX_STOP_MACHINE |
3 | #define _LINUX_STOP_MACHINE | |
1142d810 | 4 | |
1da177e4 | 5 | #include <linux/cpu.h> |
eeec4fad | 6 | #include <linux/cpumask.h> |
bb2eac66 | 7 | #include <linux/smp.h> |
1142d810 | 8 | #include <linux/list.h> |
1da177e4 | 9 | |
1142d810 TH |
10 | /* |
11 | * stop_cpu[s]() is simplistic per-cpu maximum priority cpu | |
12 | * monopolization mechanism. The caller can specify a non-sleeping | |
13 | * function to be executed on a single or multiple cpus preempting all | |
14 | * other processes and monopolizing those cpus until it finishes. | |
15 | * | |
16 | * Resources for this mechanism are preallocated when a cpu is brought | |
17 | * up and requests are guaranteed to be served as long as the target | |
18 | * cpus are online. | |
19 | */ | |
1142d810 TH |
20 | typedef int (*cpu_stop_fn_t)(void *arg); |
21 | ||
bbf1bb3e TH |
22 | #ifdef CONFIG_SMP |
23 | ||
1142d810 TH |
24 | struct cpu_stop_work { |
25 | struct list_head list; /* cpu_stopper->works */ | |
26 | cpu_stop_fn_t fn; | |
a8b62fd0 | 27 | unsigned long caller; |
1142d810 TH |
28 | void *arg; |
29 | struct cpu_stop_done *done; | |
30 | }; | |
31 | ||
32 | int stop_one_cpu(unsigned int cpu, cpu_stop_fn_t fn, void *arg); | |
1be0bd77 | 33 | int stop_two_cpus(unsigned int cpu1, unsigned int cpu2, cpu_stop_fn_t fn, void *arg); |
1b034bd9 | 34 | bool stop_one_cpu_nowait(unsigned int cpu, cpu_stop_fn_t fn, void *arg, |
1142d810 | 35 | struct cpu_stop_work *work_buf); |
233e7f26 | 36 | void stop_machine_park(int cpu); |
c00166d8 | 37 | void stop_machine_unpark(int cpu); |
4ecf0a43 | 38 | void stop_machine_yield(const struct cpumask *cpumask); |
1142d810 | 39 | |
a8b62fd0 PZ |
40 | extern void print_stop_info(const char *log_lvl, struct task_struct *task); |
41 | ||
bbf1bb3e TH |
42 | #else /* CONFIG_SMP */ |
43 | ||
44 | #include <linux/workqueue.h> | |
45 | ||
46 | struct cpu_stop_work { | |
47 | struct work_struct work; | |
48 | cpu_stop_fn_t fn; | |
49 | void *arg; | |
50 | }; | |
51 | ||
52 | static inline int stop_one_cpu(unsigned int cpu, cpu_stop_fn_t fn, void *arg) | |
53 | { | |
54 | int ret = -ENOENT; | |
55 | preempt_disable(); | |
56 | if (cpu == smp_processor_id()) | |
57 | ret = fn(arg); | |
58 | preempt_enable(); | |
59 | return ret; | |
60 | } | |
61 | ||
62 | static void stop_one_cpu_nowait_workfn(struct work_struct *work) | |
63 | { | |
64 | struct cpu_stop_work *stwork = | |
65 | container_of(work, struct cpu_stop_work, work); | |
66 | preempt_disable(); | |
67 | stwork->fn(stwork->arg); | |
68 | preempt_enable(); | |
69 | } | |
70 | ||
1b034bd9 | 71 | static inline bool stop_one_cpu_nowait(unsigned int cpu, |
bbf1bb3e TH |
72 | cpu_stop_fn_t fn, void *arg, |
73 | struct cpu_stop_work *work_buf) | |
74 | { | |
75 | if (cpu == smp_processor_id()) { | |
76 | INIT_WORK(&work_buf->work, stop_one_cpu_nowait_workfn); | |
77 | work_buf->fn = fn; | |
78 | work_buf->arg = arg; | |
79 | schedule_work(&work_buf->work); | |
1b034bd9 | 80 | return true; |
bbf1bb3e | 81 | } |
1b034bd9 ON |
82 | |
83 | return false; | |
bbf1bb3e TH |
84 | } |
85 | ||
a8b62fd0 PZ |
86 | static inline void print_stop_info(const char *log_lvl, struct task_struct *task) { } |
87 | ||
bbf1bb3e TH |
88 | #endif /* CONFIG_SMP */ |
89 | ||
1142d810 TH |
90 | /* |
91 | * stop_machine "Bogolock": stop the entire machine, disable | |
92 | * interrupts. This is a very heavy lock, which is equivalent to | |
93 | * grabbing every spinlock (and more). So the "read" side to such a | |
1816315b | 94 | * lock is anything which disables preemption. |
1142d810 | 95 | */ |
86fffe4a | 96 | #if defined(CONFIG_SMP) || defined(CONFIG_HOTPLUG_CPU) |
1142d810 | 97 | |
1da177e4 | 98 | /** |
eeec4fad | 99 | * stop_machine: freeze the machine on all CPUs and run this function |
1da177e4 LT |
100 | * @fn: the function to run |
101 | * @data: the data ptr for the @fn() | |
eeec4fad | 102 | * @cpus: the cpus to run the @fn() on (NULL = any online cpu) |
1da177e4 | 103 | * |
ffdb5976 | 104 | * Description: This causes a thread to be scheduled on every cpu, |
25985edc | 105 | * each of which disables interrupts. The result is that no one is |
ffdb5976 RR |
106 | * holding a spinlock or inside any other preempt-disabled region when |
107 | * @fn() runs. | |
1da177e4 LT |
108 | * |
109 | * This can be thought of as a very heavy write lock, equivalent to | |
fe5595c0 SAS |
110 | * grabbing every spinlock in the kernel. |
111 | * | |
112 | * Protects against CPU hotplug. | |
113 | */ | |
9a301f22 | 114 | int stop_machine(cpu_stop_fn_t fn, void *data, const struct cpumask *cpus); |
1da177e4 | 115 | |
fe5595c0 SAS |
116 | /** |
117 | * stop_machine_cpuslocked: freeze the machine on all CPUs and run this function | |
118 | * @fn: the function to run | |
119 | * @data: the data ptr for the @fn() | |
120 | * @cpus: the cpus to run the @fn() on (NULL = any online cpu) | |
121 | * | |
122 | * Same as above. Must be called from with in a cpus_read_lock() protected | |
123 | * region. Avoids nested calls to cpus_read_lock(). | |
124 | */ | |
125 | int stop_machine_cpuslocked(cpu_stop_fn_t fn, void *data, const struct cpumask *cpus); | |
126 | ||
2760f5a4 PZ |
127 | /** |
128 | * stop_core_cpuslocked: - stop all threads on just one core | |
129 | * @cpu: any cpu in the targeted core | |
130 | * @fn: the function to run | |
131 | * @data: the data ptr for @fn() | |
132 | * | |
133 | * Same as above, but instead of every CPU, only the logical CPUs of a | |
134 | * single core are affected. | |
135 | * | |
136 | * Context: Must be called from within a cpus_read_lock() protected region. | |
137 | * | |
138 | * Return: 0 if all executions of @fn returned 0, any non zero return | |
139 | * value if any returned non zero. | |
140 | */ | |
141 | int stop_core_cpuslocked(unsigned int cpu, cpu_stop_fn_t fn, void *data); | |
142 | ||
9a301f22 | 143 | int stop_machine_from_inactive_cpu(cpu_stop_fn_t fn, void *data, |
f740e6cd | 144 | const struct cpumask *cpus); |
86fffe4a | 145 | #else /* CONFIG_SMP || CONFIG_HOTPLUG_CPU */ |
1da177e4 | 146 | |
cbf78d85 | 147 | static __always_inline int stop_machine_cpuslocked(cpu_stop_fn_t fn, void *data, |
fe5595c0 | 148 | const struct cpumask *cpus) |
1da177e4 | 149 | { |
f740e6cd | 150 | unsigned long flags; |
1da177e4 | 151 | int ret; |
f740e6cd | 152 | local_irq_save(flags); |
1da177e4 | 153 | ret = fn(data); |
f740e6cd | 154 | local_irq_restore(flags); |
1da177e4 LT |
155 | return ret; |
156 | } | |
9ea09af3 | 157 | |
cbf78d85 AB |
158 | static __always_inline int |
159 | stop_machine(cpu_stop_fn_t fn, void *data, const struct cpumask *cpus) | |
fe5595c0 SAS |
160 | { |
161 | return stop_machine_cpuslocked(fn, data, cpus); | |
162 | } | |
163 | ||
cbf78d85 AB |
164 | static __always_inline int |
165 | stop_machine_from_inactive_cpu(cpu_stop_fn_t fn, void *data, | |
166 | const struct cpumask *cpus) | |
f740e6cd | 167 | { |
7eeb088e | 168 | return stop_machine(fn, data, cpus); |
f740e6cd TH |
169 | } |
170 | ||
86fffe4a | 171 | #endif /* CONFIG_SMP || CONFIG_HOTPLUG_CPU */ |
bbf1bb3e | 172 | #endif /* _LINUX_STOP_MACHINE */ |