1/* SPDX-License-Identifier: GPL-2.0 */
2#ifndef __LINUX_SMP_H
3#define __LINUX_SMP_H
4
5/*
6 * Generic SMP support
7 * Alan Cox. <alan@redhat.com>
8 */
9
10#include <linux/errno.h>
11#include <linux/types.h>
12#include <linux/list.h>
13#include <linux/cpumask.h>
14#include <linux/init.h>
15#include <linux/smp_types.h>
16
17typedef void (*smp_call_func_t)(void *info);
18typedef bool (*smp_cond_func_t)(int cpu, void *info);
19
20/*
21 * structure shares (partial) layout with struct irq_work
22 */
23struct __call_single_data {
24 struct __call_single_node node;
25 smp_call_func_t func;
26 void *info;
27};
28
29#define CSD_INIT(_func, _info) \
30 (struct __call_single_data){ .func = (_func), .info = (_info), }
31
32/* Use __aligned() to avoid to use 2 cache lines for 1 csd */
33typedef struct __call_single_data call_single_data_t
34 __aligned(sizeof(struct __call_single_data));
35
36#define INIT_CSD(_csd, _func, _info) \
37do { \
38 *(_csd) = CSD_INIT((_func), (_info)); \
39} while (0)
40
41/*
42 * Enqueue a llist_node on the call_single_queue; be very careful, read
43 * flush_smp_call_function_queue() in detail.
44 */
45extern void __smp_call_single_queue(int cpu, struct llist_node *node);
46
47/* total number of cpus in this system (may exceed NR_CPUS) */
48extern unsigned int total_cpus;
49
50int smp_call_function_single(int cpuid, smp_call_func_t func, void *info,
51 int wait);
52
53void on_each_cpu_cond_mask(smp_cond_func_t cond_func, smp_call_func_t func,
54 void *info, bool wait, const struct cpumask *mask);
55
56int smp_call_function_single_async(int cpu, struct __call_single_data *csd);
57
58/*
59 * Cpus stopping functions in panic. All have default weak definitions.
60 * Architecture-dependent code may override them.
61 */
62void panic_smp_self_stop(void);
63void nmi_panic_self_stop(struct pt_regs *regs);
64void crash_smp_send_stop(void);
65
66/*
67 * Call a function on all processors
68 */
69static inline void on_each_cpu(smp_call_func_t func, void *info, int wait)
70{
71 on_each_cpu_cond_mask(NULL, func, info, wait, cpu_online_mask);
72}
73
74/**
75 * on_each_cpu_mask(): Run a function on processors specified by
76 * cpumask, which may include the local processor.
77 * @mask: The set of cpus to run on (only runs on online subset).
78 * @func: The function to run. This must be fast and non-blocking.
79 * @info: An arbitrary pointer to pass to the function.
80 * @wait: If true, wait (atomically) until function has completed
81 * on other CPUs.
82 *
83 * If @wait is true, then returns once @func has returned.
84 *
85 * You must not call this function with disabled interrupts or from a
86 * hardware interrupt handler or from a bottom half handler. The
87 * exception is that it may be used during early boot while
88 * early_boot_irqs_disabled is set.
89 */
90static inline void on_each_cpu_mask(const struct cpumask *mask,
91 smp_call_func_t func, void *info, bool wait)
92{
93 on_each_cpu_cond_mask(NULL, func, info, wait, mask);
94}
95
96/*
97 * Call a function on each processor for which the supplied function
98 * cond_func returns a positive value. This may include the local
99 * processor. May be used during early boot while early_boot_irqs_disabled is
100 * set. Use local_irq_save/restore() instead of local_irq_disable/enable().
101 */
102static inline void on_each_cpu_cond(smp_cond_func_t cond_func,
103 smp_call_func_t func, void *info, bool wait)
104{
105 on_each_cpu_cond_mask(cond_func, func, info, wait, cpu_online_mask);
106}
107
108#ifdef CONFIG_SMP
109
110#include <linux/preempt.h>
111#include <linux/compiler.h>
112#include <linux/thread_info.h>
113#include <asm/smp.h>
114
115/*
116 * main cross-CPU interfaces, handles INIT, TLB flush, STOP, etc.
117 * (defined in asm header):
118 */
119
120/*
121 * stops all CPUs but the current one:
122 */
123extern void smp_send_stop(void);
124
125/*
126 * sends a 'reschedule' event to another CPU:
127 */
128extern void smp_send_reschedule(int cpu);
129
130
131/*
132 * Prepare machine for booting other CPUs.
133 */
134extern void smp_prepare_cpus(unsigned int max_cpus);
135
136/*
137 * Bring a CPU up
138 */
139extern int __cpu_up(unsigned int cpunum, struct task_struct *tidle);
140
141/*
142 * Final polishing of CPUs
143 */
144extern void smp_cpus_done(unsigned int max_cpus);
145
146/*
147 * Call a function on all other processors
148 */
149void smp_call_function(smp_call_func_t func, void *info, int wait);
150void smp_call_function_many(const struct cpumask *mask,
151 smp_call_func_t func, void *info, bool wait);
152
153int smp_call_function_any(const struct cpumask *mask,
154 smp_call_func_t func, void *info, int wait);
155
156void kick_all_cpus_sync(void);
157void wake_up_all_idle_cpus(void);
158
159/*
160 * Generic and arch helpers
161 */
162void __init call_function_init(void);
163void generic_smp_call_function_single_interrupt(void);
164#define generic_smp_call_function_interrupt \
165 generic_smp_call_function_single_interrupt
166
167/*
168 * Mark the boot cpu "online" so that it can call console drivers in
169 * printk() and can access its per-cpu storage.
170 */
171void smp_prepare_boot_cpu(void);
172
173extern unsigned int setup_max_cpus;
174extern void __init setup_nr_cpu_ids(void);
175extern void __init smp_init(void);
176
177extern int __boot_cpu_id;
178
179static inline int get_boot_cpu_id(void)
180{
181 return __boot_cpu_id;
182}
183
184#else /* !SMP */
185
186static inline void smp_send_stop(void) { }
187
188/*
189 * These macros fold the SMP functionality into a single CPU system
190 */
191#define raw_smp_processor_id() 0
192static inline void up_smp_call_function(smp_call_func_t func, void *info)
193{
194}
195#define smp_call_function(func, info, wait) \
196 (up_smp_call_function(func, info))
197
198static inline void smp_send_reschedule(int cpu) { }
199#define smp_prepare_boot_cpu() do {} while (0)
200#define smp_call_function_many(mask, func, info, wait) \
201 (up_smp_call_function(func, info))
202static inline void call_function_init(void) { }
203
204static inline int
205smp_call_function_any(const struct cpumask *mask, smp_call_func_t func,
206 void *info, int wait)
207{
208 return smp_call_function_single(cpuid: 0, func, info, wait);
209}
210
211static inline void kick_all_cpus_sync(void) { }
212static inline void wake_up_all_idle_cpus(void) { }
213
214#ifdef CONFIG_UP_LATE_INIT
215extern void __init up_late_init(void);
216static inline void smp_init(void) { up_late_init(); }
217#else
218static inline void smp_init(void) { }
219#endif
220
221static inline int get_boot_cpu_id(void)
222{
223 return 0;
224}
225
226#endif /* !SMP */
227
228/**
229 * raw_processor_id() - get the current (unstable) CPU id
230 *
231 * For then you know what you are doing and need an unstable
232 * CPU id.
233 */
234
235/**
236 * smp_processor_id() - get the current (stable) CPU id
237 *
238 * This is the normal accessor to the CPU id and should be used
239 * whenever possible.
240 *
241 * The CPU id is stable when:
242 *
243 * - IRQs are disabled;
244 * - preemption is disabled;
245 * - the task is CPU affine.
246 *
247 * When CONFIG_DEBUG_PREEMPT; we verify these assumption and WARN
248 * when smp_processor_id() is used when the CPU id is not stable.
249 */
250
251/*
252 * Allow the architecture to differentiate between a stable and unstable read.
253 * For example, x86 uses an IRQ-safe asm-volatile read for the unstable but a
254 * regular asm read for the stable.
255 */
256#ifndef __smp_processor_id
257#define __smp_processor_id(x) raw_smp_processor_id(x)
258#endif
259
260#ifdef CONFIG_DEBUG_PREEMPT
261 extern unsigned int debug_smp_processor_id(void);
262# define smp_processor_id() debug_smp_processor_id()
263#else
264# define smp_processor_id() __smp_processor_id()
265#endif
266
267#define get_cpu() ({ preempt_disable(); __smp_processor_id(); })
268#define put_cpu() preempt_enable()
269
270/*
271 * Callback to arch code if there's nosmp or maxcpus=0 on the
272 * boot command line:
273 */
274extern void arch_disable_smp_support(void);
275
276extern void arch_thaw_secondary_cpus_begin(void);
277extern void arch_thaw_secondary_cpus_end(void);
278
279void smp_setup_processor_id(void);
280
281int smp_call_on_cpu(unsigned int cpu, int (*func)(void *), void *par,
282 bool phys);
283
284/* SMP core functions */
285int smpcfd_prepare_cpu(unsigned int cpu);
286int smpcfd_dead_cpu(unsigned int cpu);
287int smpcfd_dying_cpu(unsigned int cpu);
288
289#endif /* __LINUX_SMP_H */
290

source code of linux/include/linux/smp.h