xref: /linux-6.15/include/linux/smp.h (revision a5f6ea29)
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 extern void cpu_idle(void);
17 
18 typedef void (*smp_call_func_t)(void *info);
19 struct call_single_data {
20 	union {
21 		struct list_head list;
22 		struct llist_node llist;
23 	};
24 	smp_call_func_t func;
25 	void *info;
26 	u16 flags;
27 };
28 
29 /* total number of cpus in this system (may exceed NR_CPUS) */
30 extern unsigned int total_cpus;
31 
32 int smp_call_function_single(int cpuid, smp_call_func_t func, void *info,
33 			     int wait);
34 
35 /*
36  * Call a function on all processors
37  */
38 int on_each_cpu(smp_call_func_t func, void *info, int wait);
39 
40 /*
41  * Call a function on processors specified by mask, which might include
42  * the local one.
43  */
44 void on_each_cpu_mask(const struct cpumask *mask, smp_call_func_t func,
45 		void *info, bool wait);
46 
47 /*
48  * Call a function on each processor for which the supplied function
49  * cond_func returns a positive value. This may include the local
50  * processor.
51  */
52 void on_each_cpu_cond(bool (*cond_func)(int cpu, void *info),
53 		smp_call_func_t func, void *info, bool wait,
54 		gfp_t gfp_flags);
55 
56 void __smp_call_function_single(int cpuid, struct call_single_data *data,
57 				int wait);
58 
59 #ifdef CONFIG_SMP
60 
61 #include <linux/preempt.h>
62 #include <linux/kernel.h>
63 #include <linux/compiler.h>
64 #include <linux/thread_info.h>
65 #include <asm/smp.h>
66 
67 /*
68  * main cross-CPU interfaces, handles INIT, TLB flush, STOP, etc.
69  * (defined in asm header):
70  */
71 
72 /*
73  * stops all CPUs but the current one:
74  */
75 extern void smp_send_stop(void);
76 
77 /*
78  * sends a 'reschedule' event to another CPU:
79  */
80 extern void smp_send_reschedule(int cpu);
81 
82 
83 /*
84  * Prepare machine for booting other CPUs.
85  */
86 extern void smp_prepare_cpus(unsigned int max_cpus);
87 
88 /*
89  * Bring a CPU up
90  */
91 extern int __cpu_up(unsigned int cpunum, struct task_struct *tidle);
92 
93 /*
94  * Final polishing of CPUs
95  */
96 extern void smp_cpus_done(unsigned int max_cpus);
97 
98 /*
99  * Call a function on all other processors
100  */
101 int smp_call_function(smp_call_func_t func, void *info, int wait);
102 void smp_call_function_many(const struct cpumask *mask,
103 			    smp_call_func_t func, void *info, bool wait);
104 
105 int smp_call_function_any(const struct cpumask *mask,
106 			  smp_call_func_t func, void *info, int wait);
107 
108 void kick_all_cpus_sync(void);
109 
110 /*
111  * Generic and arch helpers
112  */
113 void __init call_function_init(void);
114 void generic_smp_call_function_single_interrupt(void);
115 #define generic_smp_call_function_interrupt \
116 	generic_smp_call_function_single_interrupt
117 
118 /*
119  * Mark the boot cpu "online" so that it can call console drivers in
120  * printk() and can access its per-cpu storage.
121  */
122 void smp_prepare_boot_cpu(void);
123 
124 extern unsigned int setup_max_cpus;
125 extern void __init setup_nr_cpu_ids(void);
126 extern void __init smp_init(void);
127 
128 #else /* !SMP */
129 
130 static inline void smp_send_stop(void) { }
131 
132 /*
133  *	These macros fold the SMP functionality into a single CPU system
134  */
135 #define raw_smp_processor_id()			0
136 static inline int up_smp_call_function(smp_call_func_t func, void *info)
137 {
138 	return 0;
139 }
140 #define smp_call_function(func, info, wait) \
141 			(up_smp_call_function(func, info))
142 
143 static inline void smp_send_reschedule(int cpu) { }
144 #define smp_prepare_boot_cpu()			do {} while (0)
145 #define smp_call_function_many(mask, func, info, wait) \
146 			(up_smp_call_function(func, info))
147 static inline void call_function_init(void) { }
148 
149 static inline int
150 smp_call_function_any(const struct cpumask *mask, smp_call_func_t func,
151 		      void *info, int wait)
152 {
153 	return smp_call_function_single(0, func, info, wait);
154 }
155 
156 static inline void kick_all_cpus_sync(void) {  }
157 
158 #endif /* !SMP */
159 
160 /*
161  * smp_processor_id(): get the current CPU ID.
162  *
163  * if DEBUG_PREEMPT is enabled then we check whether it is
164  * used in a preemption-safe way. (smp_processor_id() is safe
165  * if it's used in a preemption-off critical section, or in
166  * a thread that is bound to the current CPU.)
167  *
168  * NOTE: raw_smp_processor_id() is for internal use only
169  * (smp_processor_id() is the preferred variant), but in rare
170  * instances it might also be used to turn off false positives
171  * (i.e. smp_processor_id() use that the debugging code reports but
172  * which use for some reason is legal). Don't use this to hack around
173  * the warning message, as your code might not work under PREEMPT.
174  */
175 #ifdef CONFIG_DEBUG_PREEMPT
176   extern unsigned int debug_smp_processor_id(void);
177 # define smp_processor_id() debug_smp_processor_id()
178 #else
179 # define smp_processor_id() raw_smp_processor_id()
180 #endif
181 
182 #define get_cpu()		({ preempt_disable(); smp_processor_id(); })
183 #define put_cpu()		preempt_enable()
184 
185 /*
186  * Callback to arch code if there's nosmp or maxcpus=0 on the
187  * boot command line:
188  */
189 extern void arch_disable_smp_support(void);
190 
191 extern void arch_enable_nonboot_cpus_begin(void);
192 extern void arch_enable_nonboot_cpus_end(void);
193 
194 void smp_setup_processor_id(void);
195 
196 #endif /* __LINUX_SMP_H */
197