xref: /linux-6.15/include/linux/smp.h (revision bb66fc67)
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 	struct llist_node llist;
21 	smp_call_func_t func;
22 	void *info;
23 	u16 flags;
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 /*
33  * Call a function on all processors
34  */
35 int on_each_cpu(smp_call_func_t func, void *info, int wait);
36 
37 /*
38  * Call a function on processors specified by mask, which might include
39  * the local one.
40  */
41 void on_each_cpu_mask(const struct cpumask *mask, smp_call_func_t func,
42 		void *info, bool wait);
43 
44 /*
45  * Call a function on each processor for which the supplied function
46  * cond_func returns a positive value. This may include the local
47  * processor.
48  */
49 void on_each_cpu_cond(bool (*cond_func)(int cpu, void *info),
50 		smp_call_func_t func, void *info, bool wait,
51 		gfp_t gfp_flags);
52 
53 int smp_call_function_single_async(int cpu, struct call_single_data *csd);
54 
55 #ifdef CONFIG_SMP
56 
57 #include <linux/preempt.h>
58 #include <linux/kernel.h>
59 #include <linux/compiler.h>
60 #include <linux/thread_info.h>
61 #include <asm/smp.h>
62 
63 /*
64  * main cross-CPU interfaces, handles INIT, TLB flush, STOP, etc.
65  * (defined in asm header):
66  */
67 
68 /*
69  * stops all CPUs but the current one:
70  */
71 extern void smp_send_stop(void);
72 
73 /*
74  * sends a 'reschedule' event to another CPU:
75  */
76 extern void smp_send_reschedule(int cpu);
77 
78 
79 /*
80  * Prepare machine for booting other CPUs.
81  */
82 extern void smp_prepare_cpus(unsigned int max_cpus);
83 
84 /*
85  * Bring a CPU up
86  */
87 extern int __cpu_up(unsigned int cpunum, struct task_struct *tidle);
88 
89 /*
90  * Final polishing of CPUs
91  */
92 extern void smp_cpus_done(unsigned int max_cpus);
93 
94 /*
95  * Call a function on all other processors
96  */
97 int smp_call_function(smp_call_func_t func, void *info, int wait);
98 void smp_call_function_many(const struct cpumask *mask,
99 			    smp_call_func_t func, void *info, bool wait);
100 
101 int smp_call_function_any(const struct cpumask *mask,
102 			  smp_call_func_t func, void *info, int wait);
103 
104 void kick_all_cpus_sync(void);
105 
106 /*
107  * Generic and arch helpers
108  */
109 void __init call_function_init(void);
110 void generic_smp_call_function_single_interrupt(void);
111 #define generic_smp_call_function_interrupt \
112 	generic_smp_call_function_single_interrupt
113 
114 /*
115  * Mark the boot cpu "online" so that it can call console drivers in
116  * printk() and can access its per-cpu storage.
117  */
118 void smp_prepare_boot_cpu(void);
119 
120 extern unsigned int setup_max_cpus;
121 extern void __init setup_nr_cpu_ids(void);
122 extern void __init smp_init(void);
123 
124 #else /* !SMP */
125 
126 static inline void smp_send_stop(void) { }
127 
128 /*
129  *	These macros fold the SMP functionality into a single CPU system
130  */
131 #define raw_smp_processor_id()			0
132 static inline int up_smp_call_function(smp_call_func_t func, void *info)
133 {
134 	return 0;
135 }
136 #define smp_call_function(func, info, wait) \
137 			(up_smp_call_function(func, info))
138 
139 static inline void smp_send_reschedule(int cpu) { }
140 #define smp_prepare_boot_cpu()			do {} while (0)
141 #define smp_call_function_many(mask, func, info, wait) \
142 			(up_smp_call_function(func, info))
143 static inline void call_function_init(void) { }
144 
145 static inline int
146 smp_call_function_any(const struct cpumask *mask, smp_call_func_t func,
147 		      void *info, int wait)
148 {
149 	return smp_call_function_single(0, func, info, wait);
150 }
151 
152 static inline void kick_all_cpus_sync(void) {  }
153 
154 #endif /* !SMP */
155 
156 /*
157  * smp_processor_id(): get the current CPU ID.
158  *
159  * if DEBUG_PREEMPT is enabled then we check whether it is
160  * used in a preemption-safe way. (smp_processor_id() is safe
161  * if it's used in a preemption-off critical section, or in
162  * a thread that is bound to the current CPU.)
163  *
164  * NOTE: raw_smp_processor_id() is for internal use only
165  * (smp_processor_id() is the preferred variant), but in rare
166  * instances it might also be used to turn off false positives
167  * (i.e. smp_processor_id() use that the debugging code reports but
168  * which use for some reason is legal). Don't use this to hack around
169  * the warning message, as your code might not work under PREEMPT.
170  */
171 #ifdef CONFIG_DEBUG_PREEMPT
172   extern unsigned int debug_smp_processor_id(void);
173 # define smp_processor_id() debug_smp_processor_id()
174 #else
175 # define smp_processor_id() raw_smp_processor_id()
176 #endif
177 
178 #define get_cpu()		({ preempt_disable(); smp_processor_id(); })
179 #define put_cpu()		preempt_enable()
180 
181 /*
182  * Callback to arch code if there's nosmp or maxcpus=0 on the
183  * boot command line:
184  */
185 extern void arch_disable_smp_support(void);
186 
187 extern void arch_enable_nonboot_cpus_begin(void);
188 extern void arch_enable_nonboot_cpus_end(void);
189 
190 void smp_setup_processor_id(void);
191 
192 #endif /* __LINUX_SMP_H */
193