xref: /linux-6.15/include/linux/smp.h (revision 71ccc212)
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 
14 extern void cpu_idle(void);
15 
16 struct call_single_data {
17 	struct list_head list;
18 	void (*func) (void *info);
19 	void *info;
20 	u16 flags;
21 	u16 priv;
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, void (*func) (void *info), void *info,
28 				int wait);
29 
30 #ifdef CONFIG_SMP
31 
32 #include <linux/preempt.h>
33 #include <linux/kernel.h>
34 #include <linux/compiler.h>
35 #include <linux/thread_info.h>
36 #include <asm/smp.h>
37 
38 /*
39  * main cross-CPU interfaces, handles INIT, TLB flush, STOP, etc.
40  * (defined in asm header):
41  */
42 
43 /*
44  * stops all CPUs but the current one:
45  */
46 extern void smp_send_stop(void);
47 
48 /*
49  * sends a 'reschedule' event to another CPU:
50  */
51 extern void smp_send_reschedule(int cpu);
52 
53 
54 /*
55  * Prepare machine for booting other CPUs.
56  */
57 extern void smp_prepare_cpus(unsigned int max_cpus);
58 
59 /*
60  * Bring a CPU up
61  */
62 extern int __cpu_up(unsigned int cpunum);
63 
64 /*
65  * Final polishing of CPUs
66  */
67 extern void smp_cpus_done(unsigned int max_cpus);
68 
69 /*
70  * Call a function on all other processors
71  */
72 int smp_call_function(void(*func)(void *info), void *info, int wait);
73 void smp_call_function_many(const struct cpumask *mask,
74 			    void (*func)(void *info), void *info, bool wait);
75 
76 void __smp_call_function_single(int cpuid, struct call_single_data *data,
77 				int wait);
78 
79 int smp_call_function_any(const struct cpumask *mask,
80 			  void (*func)(void *info), void *info, int wait);
81 
82 /*
83  * Generic and arch helpers
84  */
85 #ifdef CONFIG_USE_GENERIC_SMP_HELPERS
86 void generic_smp_call_function_single_interrupt(void);
87 void generic_smp_call_function_interrupt(void);
88 void ipi_call_lock(void);
89 void ipi_call_unlock(void);
90 void ipi_call_lock_irq(void);
91 void ipi_call_unlock_irq(void);
92 #endif
93 
94 /*
95  * Call a function on all processors
96  */
97 int on_each_cpu(void (*func) (void *info), void *info, int wait);
98 
99 #define MSG_ALL_BUT_SELF	0x8000	/* Assume <32768 CPU's */
100 #define MSG_ALL			0x8001
101 
102 #define MSG_INVALIDATE_TLB	0x0001	/* Remote processor TLB invalidate */
103 #define MSG_STOP_CPU		0x0002	/* Sent to shut down slave CPU's
104 					 * when rebooting
105 					 */
106 #define MSG_RESCHEDULE		0x0003	/* Reschedule request from master CPU*/
107 #define MSG_CALL_FUNCTION       0x0004  /* Call function on all other CPUs */
108 
109 /*
110  * Mark the boot cpu "online" so that it can call console drivers in
111  * printk() and can access its per-cpu storage.
112  */
113 void smp_prepare_boot_cpu(void);
114 
115 extern unsigned int setup_max_cpus;
116 
117 #else /* !SMP */
118 
119 static inline void smp_send_stop(void) { }
120 
121 /*
122  *	These macros fold the SMP functionality into a single CPU system
123  */
124 #define raw_smp_processor_id()			0
125 static inline int up_smp_call_function(void (*func)(void *), void *info)
126 {
127 	return 0;
128 }
129 #define smp_call_function(func, info, wait) \
130 			(up_smp_call_function(func, info))
131 #define on_each_cpu(func,info,wait)		\
132 	({					\
133 		local_irq_disable();		\
134 		func(info);			\
135 		local_irq_enable();		\
136 		0;				\
137 	})
138 static inline void smp_send_reschedule(int cpu) { }
139 #define num_booting_cpus()			1
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 init_call_single_data(void) { }
144 
145 static inline int
146 smp_call_function_any(const struct cpumask *mask, void (*func)(void *info),
147 		      void *info, int wait)
148 {
149 	return smp_call_function_single(0, func, info, wait);
150 }
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 void smp_setup_processor_id(void);
186 
187 #endif /* __LINUX_SMP_H */
188