xref: /linux-6.15/include/linux/smp.h (revision 261a9af6)
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 
15 extern void cpu_idle(void);
16 
17 typedef void (*smp_call_func_t)(void *info);
18 struct call_single_data {
19 	struct list_head list;
20 	smp_call_func_t func;
21 	void *info;
22 	u16 flags;
23 	u16 priv;
24 };
25 
26 /* total number of cpus in this system (may exceed NR_CPUS) */
27 extern unsigned int total_cpus;
28 
29 int smp_call_function_single(int cpuid, smp_call_func_t func, void *info,
30 			     int wait);
31 
32 #ifdef CONFIG_SMP
33 
34 #include <linux/preempt.h>
35 #include <linux/kernel.h>
36 #include <linux/compiler.h>
37 #include <linux/thread_info.h>
38 #include <asm/smp.h>
39 
40 /*
41  * main cross-CPU interfaces, handles INIT, TLB flush, STOP, etc.
42  * (defined in asm header):
43  */
44 
45 /*
46  * stops all CPUs but the current one:
47  */
48 extern void smp_send_stop(void);
49 
50 /*
51  * sends a 'reschedule' event to another CPU:
52  */
53 extern void smp_send_reschedule(int cpu);
54 
55 
56 /*
57  * Prepare machine for booting other CPUs.
58  */
59 extern void smp_prepare_cpus(unsigned int max_cpus);
60 
61 /*
62  * Bring a CPU up
63  */
64 extern int __cpu_up(unsigned int cpunum);
65 
66 /*
67  * Final polishing of CPUs
68  */
69 extern void smp_cpus_done(unsigned int max_cpus);
70 
71 /*
72  * Call a function on all other processors
73  */
74 int smp_call_function(smp_call_func_t func, void *info, int wait);
75 void smp_call_function_many(const struct cpumask *mask,
76 			    smp_call_func_t func, void *info, bool wait);
77 
78 void __smp_call_function_single(int cpuid, struct call_single_data *data,
79 				int wait);
80 
81 int smp_call_function_any(const struct cpumask *mask,
82 			  smp_call_func_t func, void *info, int wait);
83 
84 /*
85  * Generic and arch helpers
86  */
87 #ifdef CONFIG_USE_GENERIC_SMP_HELPERS
88 void generic_smp_call_function_single_interrupt(void);
89 void generic_smp_call_function_interrupt(void);
90 void ipi_call_lock(void);
91 void ipi_call_unlock(void);
92 void ipi_call_lock_irq(void);
93 void ipi_call_unlock_irq(void);
94 #endif
95 
96 /*
97  * Call a function on all processors
98  */
99 int on_each_cpu(smp_call_func_t func, void *info, int wait);
100 
101 /*
102  * Mark the boot cpu "online" so that it can call console drivers in
103  * printk() and can access its per-cpu storage.
104  */
105 void smp_prepare_boot_cpu(void);
106 
107 extern unsigned int setup_max_cpus;
108 extern void __init setup_nr_cpu_ids(void);
109 extern void __init smp_init(void);
110 
111 #else /* !SMP */
112 
113 static inline void smp_send_stop(void) { }
114 
115 /*
116  *	These macros fold the SMP functionality into a single CPU system
117  */
118 #define raw_smp_processor_id()			0
119 static inline int up_smp_call_function(smp_call_func_t func, void *info)
120 {
121 	return 0;
122 }
123 #define smp_call_function(func, info, wait) \
124 			(up_smp_call_function(func, info))
125 #define on_each_cpu(func,info,wait)		\
126 	({					\
127 		local_irq_disable();		\
128 		func(info);			\
129 		local_irq_enable();		\
130 		0;				\
131 	})
132 static inline void smp_send_reschedule(int cpu) { }
133 #define num_booting_cpus()			1
134 #define smp_prepare_boot_cpu()			do {} while (0)
135 #define smp_call_function_many(mask, func, info, wait) \
136 			(up_smp_call_function(func, info))
137 static inline void init_call_single_data(void) { }
138 
139 static inline int
140 smp_call_function_any(const struct cpumask *mask, smp_call_func_t func,
141 		      void *info, int wait)
142 {
143 	return smp_call_function_single(0, func, info, wait);
144 }
145 
146 #endif /* !SMP */
147 
148 /*
149  * smp_processor_id(): get the current CPU ID.
150  *
151  * if DEBUG_PREEMPT is enabled then we check whether it is
152  * used in a preemption-safe way. (smp_processor_id() is safe
153  * if it's used in a preemption-off critical section, or in
154  * a thread that is bound to the current CPU.)
155  *
156  * NOTE: raw_smp_processor_id() is for internal use only
157  * (smp_processor_id() is the preferred variant), but in rare
158  * instances it might also be used to turn off false positives
159  * (i.e. smp_processor_id() use that the debugging code reports but
160  * which use for some reason is legal). Don't use this to hack around
161  * the warning message, as your code might not work under PREEMPT.
162  */
163 #ifdef CONFIG_DEBUG_PREEMPT
164   extern unsigned int debug_smp_processor_id(void);
165 # define smp_processor_id() debug_smp_processor_id()
166 #else
167 # define smp_processor_id() raw_smp_processor_id()
168 #endif
169 
170 #define get_cpu()		({ preempt_disable(); smp_processor_id(); })
171 #define put_cpu()		preempt_enable()
172 
173 /*
174  * Callback to arch code if there's nosmp or maxcpus=0 on the
175  * boot command line:
176  */
177 extern void arch_disable_smp_support(void);
178 
179 void smp_setup_processor_id(void);
180 
181 #endif /* __LINUX_SMP_H */
182