Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
os
linux
1#ifndef _LINUX_STOP_MACHINE
2#define _LINUX_STOP_MACHINE
3/* "Bogolock": stop the entire machine, disable interrupts. This is a
4 very heavy lock, which is equivalent to grabbing every spinlock
5 (and more). So the "read" side to such a lock is anything which
6 diables preeempt. */
7#include <linux/cpu.h>
8#include <linux/cpumask.h>
9#include <asm/system.h>
10
11#if defined(CONFIG_STOP_MACHINE) && defined(CONFIG_SMP)
12
13/* Deprecated, but useful for transition. */
14#define ALL_CPUS ~0U
15
16/**
17 * stop_machine: freeze the machine on all CPUs and run this function
18 * @fn: the function to run
19 * @data: the data ptr for the @fn()
20 * @cpus: the cpus to run the @fn() on (NULL = any online cpu)
21 *
22 * Description: This causes a thread to be scheduled on every cpu,
23 * each of which disables interrupts. The result is that noone is
24 * holding a spinlock or inside any other preempt-disabled region when
25 * @fn() runs.
26 *
27 * This can be thought of as a very heavy write lock, equivalent to
28 * grabbing every spinlock in the kernel. */
29int stop_machine(int (*fn)(void *), void *data, const cpumask_t *cpus);
30
31/**
32 * __stop_machine: freeze the machine on all CPUs and run this function
33 * @fn: the function to run
34 * @data: the data ptr for the @fn
35 * @cpus: the cpus to run the @fn() on (NULL = any online cpu)
36 *
37 * Description: This is a special version of the above, which assumes cpus
38 * won't come or go while it's being called. Used by hotplug cpu.
39 */
40int __stop_machine(int (*fn)(void *), void *data, const cpumask_t *cpus);
41#else
42
43static inline int stop_machine(int (*fn)(void *), void *data,
44 const cpumask_t *cpus)
45{
46 int ret;
47 local_irq_disable();
48 ret = fn(data);
49 local_irq_enable();
50 return ret;
51}
52#endif /* CONFIG_SMP */
53
54static inline int __deprecated stop_machine_run(int (*fn)(void *), void *data,
55 unsigned int cpu)
56{
57 /* If they don't care which cpu fn runs on, just pick one. */
58 if (cpu == NR_CPUS)
59 return stop_machine(fn, data, NULL);
60 else if (cpu == ~0U)
61 return stop_machine(fn, data, &cpu_possible_map);
62 else {
63 cpumask_t cpus = cpumask_of_cpu(cpu);
64 return stop_machine(fn, data, &cpus);
65 }
66}
67#endif /* _LINUX_STOP_MACHINE */