xref: /linux-6.15/include/linux/smp.h (revision db181ce0)
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 	u16 flags;
22 };
23 
24 /* total number of cpus in this system (may exceed NR_CPUS) */
25 extern unsigned int total_cpus;
26 
27 int smp_call_function_single(int cpuid, smp_call_func_t func, void *info,
28 			     int wait);
29 
30 /*
31  * Call a function on all processors
32  */
33 int on_each_cpu(smp_call_func_t func, void *info, int wait);
34 
35 /*
36  * Call a function on processors specified by mask, which might include
37  * the local one.
38  */
39 void on_each_cpu_mask(const struct cpumask *mask, smp_call_func_t func,
40 		void *info, bool wait);
41 
42 /*
43  * Call a function on each processor for which the supplied function
44  * cond_func returns a positive value. This may include the local
45  * processor.
46  */
47 void on_each_cpu_cond(bool (*cond_func)(int cpu, void *info),
48 		smp_call_func_t func, void *info, bool wait,
49 		gfp_t gfp_flags);
50 
51 int smp_call_function_single_async(int cpu, struct call_single_data *csd);
52 
53 #ifdef CONFIG_SMP
54 
55 #include <linux/preempt.h>
56 #include <linux/kernel.h>
57 #include <linux/compiler.h>
58 #include <linux/thread_info.h>
59 #include <asm/smp.h>
60 
61 /*
62  * main cross-CPU interfaces, handles INIT, TLB flush, STOP, etc.
63  * (defined in asm header):
64  */
65 
66 /*
67  * stops all CPUs but the current one:
68  */
69 extern void smp_send_stop(void);
70 
71 /*
72  * sends a 'reschedule' event to another CPU:
73  */
74 extern void smp_send_reschedule(int cpu);
75 
76 
77 /*
78  * Prepare machine for booting other CPUs.
79  */
80 extern void smp_prepare_cpus(unsigned int max_cpus);
81 
82 /*
83  * Bring a CPU up
84  */
85 extern int __cpu_up(unsigned int cpunum, struct task_struct *tidle);
86 
87 /*
88  * Final polishing of CPUs
89  */
90 extern void smp_cpus_done(unsigned int max_cpus);
91 
92 /*
93  * Call a function on all other processors
94  */
95 int smp_call_function(smp_call_func_t func, void *info, int wait);
96 void smp_call_function_many(const struct cpumask *mask,
97 			    smp_call_func_t func, void *info, bool wait);
98 
99 int smp_call_function_any(const struct cpumask *mask,
100 			  smp_call_func_t func, void *info, int wait);
101 
102 void kick_all_cpus_sync(void);
103 
104 /*
105  * Generic and arch helpers
106  */
107 void __init call_function_init(void);
108 void generic_smp_call_function_single_interrupt(void);
109 #define generic_smp_call_function_interrupt \
110 	generic_smp_call_function_single_interrupt
111 
112 /*
113  * Mark the boot cpu "online" so that it can call console drivers in
114  * printk() and can access its per-cpu storage.
115  */
116 void smp_prepare_boot_cpu(void);
117 
118 extern unsigned int setup_max_cpus;
119 extern void __init setup_nr_cpu_ids(void);
120 extern void __init smp_init(void);
121 
122 #else /* !SMP */
123 
124 static inline void smp_send_stop(void) { }
125 
126 /*
127  *	These macros fold the SMP functionality into a single CPU system
128  */
129 #define raw_smp_processor_id()			0
130 static inline int up_smp_call_function(smp_call_func_t func, void *info)
131 {
132 	return 0;
133 }
134 #define smp_call_function(func, info, wait) \
135 			(up_smp_call_function(func, info))
136 
137 static inline void smp_send_reschedule(int cpu) { }
138 #define smp_prepare_boot_cpu()			do {} while (0)
139 #define smp_call_function_many(mask, func, info, wait) \
140 			(up_smp_call_function(func, info))
141 static inline void call_function_init(void) { }
142 
143 static inline int
144 smp_call_function_any(const struct cpumask *mask, smp_call_func_t func,
145 		      void *info, int wait)
146 {
147 	return smp_call_function_single(0, func, info, wait);
148 }
149 
150 static inline void kick_all_cpus_sync(void) {  }
151 
152 #endif /* !SMP */
153 
154 /*
155  * smp_processor_id(): get the current CPU ID.
156  *
157  * if DEBUG_PREEMPT is enabled then we check whether it is
158  * used in a preemption-safe way. (smp_processor_id() is safe
159  * if it's used in a preemption-off critical section, or in
160  * a thread that is bound to the current CPU.)
161  *
162  * NOTE: raw_smp_processor_id() is for internal use only
163  * (smp_processor_id() is the preferred variant), but in rare
164  * instances it might also be used to turn off false positives
165  * (i.e. smp_processor_id() use that the debugging code reports but
166  * which use for some reason is legal). Don't use this to hack around
167  * the warning message, as your code might not work under PREEMPT.
168  */
169 #ifdef CONFIG_DEBUG_PREEMPT
170   extern unsigned int debug_smp_processor_id(void);
171 # define smp_processor_id() debug_smp_processor_id()
172 #else
173 # define smp_processor_id() raw_smp_processor_id()
174 #endif
175 
176 #define get_cpu()		({ preempt_disable(); smp_processor_id(); })
177 #define put_cpu()		preempt_enable()
178 
179 /*
180  * Callback to arch code if there's nosmp or maxcpus=0 on the
181  * boot command line:
182  */
183 extern void arch_disable_smp_support(void);
184 
185 extern void arch_enable_nonboot_cpus_begin(void);
186 extern void arch_enable_nonboot_cpus_end(void);
187 
188 void smp_setup_processor_id(void);
189 
190 #endif /* __LINUX_SMP_H */
191