xref: /linux-6.15/include/linux/smp.h (revision c6d3aaa4)
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 /*
80  * Generic and arch helpers
81  */
82 #ifdef CONFIG_USE_GENERIC_SMP_HELPERS
83 void generic_smp_call_function_single_interrupt(void);
84 void generic_smp_call_function_interrupt(void);
85 void ipi_call_lock(void);
86 void ipi_call_unlock(void);
87 void ipi_call_lock_irq(void);
88 void ipi_call_unlock_irq(void);
89 #endif
90 
91 /*
92  * Call a function on all processors
93  */
94 int on_each_cpu(void (*func) (void *info), void *info, int wait);
95 
96 #define MSG_ALL_BUT_SELF	0x8000	/* Assume <32768 CPU's */
97 #define MSG_ALL			0x8001
98 
99 #define MSG_INVALIDATE_TLB	0x0001	/* Remote processor TLB invalidate */
100 #define MSG_STOP_CPU		0x0002	/* Sent to shut down slave CPU's
101 					 * when rebooting
102 					 */
103 #define MSG_RESCHEDULE		0x0003	/* Reschedule request from master CPU*/
104 #define MSG_CALL_FUNCTION       0x0004  /* Call function on all other CPUs */
105 
106 /*
107  * Mark the boot cpu "online" so that it can call console drivers in
108  * printk() and can access its per-cpu storage.
109  */
110 void smp_prepare_boot_cpu(void);
111 
112 extern unsigned int setup_max_cpus;
113 
114 #else /* !SMP */
115 
116 static inline void smp_send_stop(void) { }
117 
118 /*
119  *	These macros fold the SMP functionality into a single CPU system
120  */
121 #define raw_smp_processor_id()			0
122 static inline int up_smp_call_function(void (*func)(void *), void *info)
123 {
124 	return 0;
125 }
126 #define smp_call_function(func, info, wait) \
127 			(up_smp_call_function(func, info))
128 #define on_each_cpu(func,info,wait)		\
129 	({					\
130 		local_irq_disable();		\
131 		func(info);			\
132 		local_irq_enable();		\
133 		0;				\
134 	})
135 static inline void smp_send_reschedule(int cpu) { }
136 #define num_booting_cpus()			1
137 #define smp_prepare_boot_cpu()			do {} while (0)
138 #define smp_call_function_many(mask, func, info, wait) \
139 			(up_smp_call_function(func, info))
140 static inline void init_call_single_data(void)
141 {
142 }
143 #endif /* !SMP */
144 
145 /*
146  * smp_processor_id(): get the current CPU ID.
147  *
148  * if DEBUG_PREEMPT is enabled the we check whether it is
149  * used in a preemption-safe way. (smp_processor_id() is safe
150  * if it's used in a preemption-off critical section, or in
151  * a thread that is bound to the current CPU.)
152  *
153  * NOTE: raw_smp_processor_id() is for internal use only
154  * (smp_processor_id() is the preferred variant), but in rare
155  * instances it might also be used to turn off false positives
156  * (i.e. smp_processor_id() use that the debugging code reports but
157  * which use for some reason is legal). Don't use this to hack around
158  * the warning message, as your code might not work under PREEMPT.
159  */
160 #ifdef CONFIG_DEBUG_PREEMPT
161   extern unsigned int debug_smp_processor_id(void);
162 # define smp_processor_id() debug_smp_processor_id()
163 #else
164 # define smp_processor_id() raw_smp_processor_id()
165 #endif
166 
167 #define get_cpu()		({ preempt_disable(); smp_processor_id(); })
168 #define put_cpu()		preempt_enable()
169 
170 /*
171  * Callback to arch code if there's nosmp or maxcpus=0 on the
172  * boot command line:
173  */
174 extern void arch_disable_smp_support(void);
175 
176 void smp_setup_processor_id(void);
177 
178 #endif /* __LINUX_SMP_H */
179