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, call_single_data_t *csd);
57
58/*
59 * Cpus stopping functions in panic. All have default weak definitions.
60 * Architecture-dependent code may override them.
61 */
62void __noreturn panic_smp_self_stop(void);
63void __noreturn 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/*
109 * Architecture specific boot CPU setup. Defined as empty weak function in
110 * init/main.c. Architectures can override it.
111 */
112void __init smp_prepare_boot_cpu(void);
113
114#ifdef CONFIG_SMP
115
116#include <linux/preempt.h>
117#include <linux/compiler.h>
118#include <linux/thread_info.h>
119#include <asm/smp.h>
120
121/*
122 * main cross-CPU interfaces, handles INIT, TLB flush, STOP, etc.
123 * (defined in asm header):
124 */
125
126/*
127 * stops all CPUs but the current one:
128 */
129extern void smp_send_stop(void);
130
131/*
132 * sends a 'reschedule' event to another CPU:
133 */
134extern void arch_smp_send_reschedule(int cpu);
135/*
136 * scheduler_ipi() is inline so can't be passed as callback reason, but the
137 * callsite IP should be sufficient for root-causing IPIs sent from here.
138 */
139#define smp_send_reschedule(cpu) ({ \
140 trace_ipi_send_cpu(cpu, _RET_IP_, NULL); \
141 arch_smp_send_reschedule(cpu); \
142})
143
144/*
145 * Prepare machine for booting other CPUs.
146 */
147extern void smp_prepare_cpus(unsigned int max_cpus);
148
149/*
150 * Bring a CPU up
151 */
152extern int __cpu_up(unsigned int cpunum, struct task_struct *tidle);
153
154/*
155 * Final polishing of CPUs
156 */
157extern void smp_cpus_done(unsigned int max_cpus);
158
159/*
160 * Call a function on all other processors
161 */
162void smp_call_function(smp_call_func_t func, void *info, int wait);
163void smp_call_function_many(const struct cpumask *mask,
164 smp_call_func_t func, void *info, bool wait);
165
166int smp_call_function_any(const struct cpumask *mask,
167 smp_call_func_t func, void *info, int wait);
168
169void kick_all_cpus_sync(void);
170void wake_up_all_idle_cpus(void);
171
172/*
173 * Generic and arch helpers
174 */
175void __init call_function_init(void);
176void generic_smp_call_function_single_interrupt(void);
177#define generic_smp_call_function_interrupt \
178 generic_smp_call_function_single_interrupt
179
180extern unsigned int setup_max_cpus;
181extern void __init setup_nr_cpu_ids(void);
182extern void __init smp_init(void);
183
184extern int __boot_cpu_id;
185
186static inline int get_boot_cpu_id(void)
187{
188 return __boot_cpu_id;
189}
190
191#else /* !SMP */
192
193static inline void smp_send_stop(void) { }
194
195/*
196 * These macros fold the SMP functionality into a single CPU system
197 */
198#define raw_smp_processor_id() 0
199static inline void up_smp_call_function(smp_call_func_t func, void *info)
200{
201}
202#define smp_call_function(func, info, wait) \
203 (up_smp_call_function(func, info))
204
205static inline void smp_send_reschedule(int cpu) { }
206#define smp_call_function_many(mask, func, info, wait) \
207 (up_smp_call_function(func, info))
208static inline void call_function_init(void) { }
209
210static inline int
211smp_call_function_any(const struct cpumask *mask, smp_call_func_t func,
212 void *info, int wait)
213{
214 return smp_call_function_single(0, func, info, wait);
215}
216
217static inline void kick_all_cpus_sync(void) { }
218static inline void wake_up_all_idle_cpus(void) { }
219
220#define setup_max_cpus 0
221
222#ifdef CONFIG_UP_LATE_INIT
223extern void __init up_late_init(void);
224static inline void smp_init(void) { up_late_init(); }
225#else
226static inline void smp_init(void) { }
227#endif
228
229static inline int get_boot_cpu_id(void)
230{
231 return 0;
232}
233
234#endif /* !SMP */
235
236/**
237 * raw_processor_id() - get the current (unstable) CPU id
238 *
239 * For then you know what you are doing and need an unstable
240 * CPU id.
241 */
242
243/**
244 * smp_processor_id() - get the current (stable) CPU id
245 *
246 * This is the normal accessor to the CPU id and should be used
247 * whenever possible.
248 *
249 * The CPU id is stable when:
250 *
251 * - IRQs are disabled;
252 * - preemption is disabled;
253 * - the task is CPU affine.
254 *
255 * When CONFIG_DEBUG_PREEMPT; we verify these assumption and WARN
256 * when smp_processor_id() is used when the CPU id is not stable.
257 */
258
259/*
260 * Allow the architecture to differentiate between a stable and unstable read.
261 * For example, x86 uses an IRQ-safe asm-volatile read for the unstable but a
262 * regular asm read for the stable.
263 */
264#ifndef __smp_processor_id
265#define __smp_processor_id() raw_smp_processor_id()
266#endif
267
268#ifdef CONFIG_DEBUG_PREEMPT
269 extern unsigned int debug_smp_processor_id(void);
270# define smp_processor_id() debug_smp_processor_id()
271#else
272# define smp_processor_id() __smp_processor_id()
273#endif
274
275#define get_cpu() ({ preempt_disable(); __smp_processor_id(); })
276#define put_cpu() preempt_enable()
277
278/*
279 * Callback to arch code if there's nosmp or maxcpus=0 on the
280 * boot command line:
281 */
282extern void arch_disable_smp_support(void);
283
284extern void arch_thaw_secondary_cpus_begin(void);
285extern void arch_thaw_secondary_cpus_end(void);
286
287void smp_setup_processor_id(void);
288
289int smp_call_on_cpu(unsigned int cpu, int (*func)(void *), void *par,
290 bool phys);
291
292/* SMP core functions */
293int smpcfd_prepare_cpu(unsigned int cpu);
294int smpcfd_dead_cpu(unsigned int cpu);
295int smpcfd_dying_cpu(unsigned int cpu);
296
297#ifdef CONFIG_CSD_LOCK_WAIT_DEBUG
298bool csd_lock_is_stuck(void);
299#else
300static inline bool csd_lock_is_stuck(void) { return false; }
301#endif
302
303#endif /* __LINUX_SMP_H */
304

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

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