xref: /linux-6.15/include/linux/smp.h (revision bb7e5ce7)
1 #ifndef __LINUX_SMP_H
2 #define __LINUX_SMP_H
3 
4 /*
5  *	Generic SMP support
6  *		Alan Cox. <[email protected]>
7  */
8 
9 #include <linux/errno.h>
10 #include <linux/types.h>
11 #include <linux/list.h>
12 #include <linux/cpumask.h>
13 #include <linux/init.h>
14 #include <linux/llist.h>
15 
16 typedef void (*smp_call_func_t)(void *info);
17 struct __call_single_data {
18 	struct llist_node llist;
19 	smp_call_func_t func;
20 	void *info;
21 	unsigned int flags;
22 };
23 
24 /* Use __aligned() to avoid to use 2 cache lines for 1 csd */
25 typedef struct __call_single_data call_single_data_t
26 	__aligned(sizeof(struct __call_single_data));
27 
28 /* total number of cpus in this system (may exceed NR_CPUS) */
29 extern unsigned int total_cpus;
30 
31 int smp_call_function_single(int cpuid, smp_call_func_t func, void *info,
32 			     int wait);
33 
34 /*
35  * Call a function on all processors
36  */
37 int on_each_cpu(smp_call_func_t func, void *info, int wait);
38 
39 /*
40  * Call a function on processors specified by mask, which might include
41  * the local one.
42  */
43 void on_each_cpu_mask(const struct cpumask *mask, smp_call_func_t func,
44 		void *info, bool wait);
45 
46 /*
47  * Call a function on each processor for which the supplied function
48  * cond_func returns a positive value. This may include the local
49  * processor.
50  */
51 void on_each_cpu_cond(bool (*cond_func)(int cpu, void *info),
52 		smp_call_func_t func, void *info, bool wait,
53 		gfp_t gfp_flags);
54 
55 int smp_call_function_single_async(int cpu, call_single_data_t *csd);
56 
57 #ifdef CONFIG_SMP
58 
59 #include <linux/preempt.h>
60 #include <linux/kernel.h>
61 #include <linux/compiler.h>
62 #include <linux/thread_info.h>
63 #include <asm/smp.h>
64 
65 /*
66  * main cross-CPU interfaces, handles INIT, TLB flush, STOP, etc.
67  * (defined in asm header):
68  */
69 
70 /*
71  * stops all CPUs but the current one:
72  */
73 extern void smp_send_stop(void);
74 
75 /*
76  * sends a 'reschedule' event to another CPU:
77  */
78 extern void smp_send_reschedule(int cpu);
79 
80 
81 /*
82  * Prepare machine for booting other CPUs.
83  */
84 extern void smp_prepare_cpus(unsigned int max_cpus);
85 
86 /*
87  * Bring a CPU up
88  */
89 extern int __cpu_up(unsigned int cpunum, struct task_struct *tidle);
90 
91 /*
92  * Final polishing of CPUs
93  */
94 extern void smp_cpus_done(unsigned int max_cpus);
95 
96 /*
97  * Call a function on all other processors
98  */
99 int smp_call_function(smp_call_func_t func, void *info, int wait);
100 void smp_call_function_many(const struct cpumask *mask,
101 			    smp_call_func_t func, void *info, bool wait);
102 
103 int smp_call_function_any(const struct cpumask *mask,
104 			  smp_call_func_t func, void *info, int wait);
105 
106 void kick_all_cpus_sync(void);
107 void wake_up_all_idle_cpus(void);
108 
109 /*
110  * Generic and arch helpers
111  */
112 void __init call_function_init(void);
113 void generic_smp_call_function_single_interrupt(void);
114 #define generic_smp_call_function_interrupt \
115 	generic_smp_call_function_single_interrupt
116 
117 /*
118  * Mark the boot cpu "online" so that it can call console drivers in
119  * printk() and can access its per-cpu storage.
120  */
121 void smp_prepare_boot_cpu(void);
122 
123 extern unsigned int setup_max_cpus;
124 extern void __init setup_nr_cpu_ids(void);
125 extern void __init smp_init(void);
126 
127 extern int __boot_cpu_id;
128 
129 static inline int get_boot_cpu_id(void)
130 {
131 	return __boot_cpu_id;
132 }
133 
134 #else /* !SMP */
135 
136 static inline void smp_send_stop(void) { }
137 
138 /*
139  *	These macros fold the SMP functionality into a single CPU system
140  */
141 #define raw_smp_processor_id()			0
142 static inline int up_smp_call_function(smp_call_func_t func, void *info)
143 {
144 	return 0;
145 }
146 #define smp_call_function(func, info, wait) \
147 			(up_smp_call_function(func, info))
148 
149 static inline void smp_send_reschedule(int cpu) { }
150 #define smp_prepare_boot_cpu()			do {} while (0)
151 #define smp_call_function_many(mask, func, info, wait) \
152 			(up_smp_call_function(func, info))
153 static inline void call_function_init(void) { }
154 
155 static inline int
156 smp_call_function_any(const struct cpumask *mask, smp_call_func_t func,
157 		      void *info, int wait)
158 {
159 	return smp_call_function_single(0, func, info, wait);
160 }
161 
162 static inline void kick_all_cpus_sync(void) {  }
163 static inline void wake_up_all_idle_cpus(void) {  }
164 
165 #ifdef CONFIG_UP_LATE_INIT
166 extern void __init up_late_init(void);
167 static inline void smp_init(void) { up_late_init(); }
168 #else
169 static inline void smp_init(void) { }
170 #endif
171 
172 static inline int get_boot_cpu_id(void)
173 {
174 	return 0;
175 }
176 
177 #endif /* !SMP */
178 
179 /*
180  * smp_processor_id(): get the current CPU ID.
181  *
182  * if DEBUG_PREEMPT is enabled then we check whether it is
183  * used in a preemption-safe way. (smp_processor_id() is safe
184  * if it's used in a preemption-off critical section, or in
185  * a thread that is bound to the current CPU.)
186  *
187  * NOTE: raw_smp_processor_id() is for internal use only
188  * (smp_processor_id() is the preferred variant), but in rare
189  * instances it might also be used to turn off false positives
190  * (i.e. smp_processor_id() use that the debugging code reports but
191  * which use for some reason is legal). Don't use this to hack around
192  * the warning message, as your code might not work under PREEMPT.
193  */
194 #ifdef CONFIG_DEBUG_PREEMPT
195   extern unsigned int debug_smp_processor_id(void);
196 # define smp_processor_id() debug_smp_processor_id()
197 #else
198 # define smp_processor_id() raw_smp_processor_id()
199 #endif
200 
201 #define get_cpu()		({ preempt_disable(); smp_processor_id(); })
202 #define put_cpu()		preempt_enable()
203 
204 /*
205  * Callback to arch code if there's nosmp or maxcpus=0 on the
206  * boot command line:
207  */
208 extern void arch_disable_smp_support(void);
209 
210 extern void arch_enable_nonboot_cpus_begin(void);
211 extern void arch_enable_nonboot_cpus_end(void);
212 
213 void smp_setup_processor_id(void);
214 
215 int smp_call_on_cpu(unsigned int cpu, int (*func)(void *), void *par,
216 		    bool phys);
217 
218 /* SMP core functions */
219 int smpcfd_prepare_cpu(unsigned int cpu);
220 int smpcfd_dead_cpu(unsigned int cpu);
221 int smpcfd_dying_cpu(unsigned int cpu);
222 
223 #endif /* __LINUX_SMP_H */
224