xref: /linux-6.15/include/linux/smp.h (revision f15cbe6f)
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/list.h>
11 #include <linux/cpumask.h>
12 
13 extern void cpu_idle(void);
14 
15 struct call_single_data {
16 	struct list_head list;
17 	void (*func) (void *info);
18 	void *info;
19 	unsigned int flags;
20 };
21 
22 #ifdef CONFIG_SMP
23 
24 #include <linux/preempt.h>
25 #include <linux/kernel.h>
26 #include <linux/compiler.h>
27 #include <linux/thread_info.h>
28 #include <asm/smp.h>
29 
30 /*
31  * main cross-CPU interfaces, handles INIT, TLB flush, STOP, etc.
32  * (defined in asm header):
33  */
34 
35 /*
36  * stops all CPUs but the current one:
37  */
38 extern void smp_send_stop(void);
39 
40 /*
41  * sends a 'reschedule' event to another CPU:
42  */
43 extern void smp_send_reschedule(int cpu);
44 
45 
46 /*
47  * Prepare machine for booting other CPUs.
48  */
49 extern void smp_prepare_cpus(unsigned int max_cpus);
50 
51 /*
52  * Bring a CPU up
53  */
54 extern int __cpu_up(unsigned int cpunum);
55 
56 /*
57  * Final polishing of CPUs
58  */
59 extern void smp_cpus_done(unsigned int max_cpus);
60 
61 /*
62  * Call a function on all other processors
63  */
64 int smp_call_function(void(*func)(void *info), void *info, int wait);
65 int smp_call_function_mask(cpumask_t mask, void(*func)(void *info), void *info,
66 				int wait);
67 int smp_call_function_single(int cpuid, void (*func) (void *info), void *info,
68 				int wait);
69 void __smp_call_function_single(int cpuid, struct call_single_data *data);
70 
71 /*
72  * Generic and arch helpers
73  */
74 #ifdef CONFIG_USE_GENERIC_SMP_HELPERS
75 void generic_smp_call_function_single_interrupt(void);
76 void generic_smp_call_function_interrupt(void);
77 void ipi_call_lock(void);
78 void ipi_call_unlock(void);
79 void ipi_call_lock_irq(void);
80 void ipi_call_unlock_irq(void);
81 #endif
82 
83 /*
84  * Call a function on all processors
85  */
86 int on_each_cpu(void (*func) (void *info), void *info, int wait);
87 
88 #define MSG_ALL_BUT_SELF	0x8000	/* Assume <32768 CPU's */
89 #define MSG_ALL			0x8001
90 
91 #define MSG_INVALIDATE_TLB	0x0001	/* Remote processor TLB invalidate */
92 #define MSG_STOP_CPU		0x0002	/* Sent to shut down slave CPU's
93 					 * when rebooting
94 					 */
95 #define MSG_RESCHEDULE		0x0003	/* Reschedule request from master CPU*/
96 #define MSG_CALL_FUNCTION       0x0004  /* Call function on all other CPUs */
97 
98 /*
99  * Mark the boot cpu "online" so that it can call console drivers in
100  * printk() and can access its per-cpu storage.
101  */
102 void smp_prepare_boot_cpu(void);
103 
104 extern unsigned int setup_max_cpus;
105 
106 #else /* !SMP */
107 
108 /*
109  *	These macros fold the SMP functionality into a single CPU system
110  */
111 #define raw_smp_processor_id()			0
112 static inline int up_smp_call_function(void (*func)(void *), void *info)
113 {
114 	return 0;
115 }
116 #define smp_call_function(func, info, wait) \
117 			(up_smp_call_function(func, info))
118 #define on_each_cpu(func,info,wait)		\
119 	({					\
120 		local_irq_disable();		\
121 		func(info);			\
122 		local_irq_enable();		\
123 		0;				\
124 	})
125 static inline void smp_send_reschedule(int cpu) { }
126 #define num_booting_cpus()			1
127 #define smp_prepare_boot_cpu()			do {} while (0)
128 #define smp_call_function_single(cpuid, func, info, wait) \
129 ({ \
130 	WARN_ON(cpuid != 0);	\
131 	local_irq_disable();	\
132 	(func)(info);		\
133 	local_irq_enable();	\
134 	0;			\
135 })
136 #define smp_call_function_mask(mask, func, info, wait) \
137 			(up_smp_call_function(func, info))
138 static inline void init_call_single_data(void)
139 {
140 }
141 #endif /* !SMP */
142 
143 /*
144  * smp_processor_id(): get the current CPU ID.
145  *
146  * if DEBUG_PREEMPT is enabled the we check whether it is
147  * used in a preemption-safe way. (smp_processor_id() is safe
148  * if it's used in a preemption-off critical section, or in
149  * a thread that is bound to the current CPU.)
150  *
151  * NOTE: raw_smp_processor_id() is for internal use only
152  * (smp_processor_id() is the preferred variant), but in rare
153  * instances it might also be used to turn off false positives
154  * (i.e. smp_processor_id() use that the debugging code reports but
155  * which use for some reason is legal). Don't use this to hack around
156  * the warning message, as your code might not work under PREEMPT.
157  */
158 #ifdef CONFIG_DEBUG_PREEMPT
159   extern unsigned int debug_smp_processor_id(void);
160 # define smp_processor_id() debug_smp_processor_id()
161 #else
162 # define smp_processor_id() raw_smp_processor_id()
163 #endif
164 
165 #define get_cpu()		({ preempt_disable(); smp_processor_id(); })
166 #define put_cpu()		preempt_enable()
167 #define put_cpu_no_resched()	preempt_enable_no_resched()
168 
169 void smp_setup_processor_id(void);
170 
171 #endif /* __LINUX_SMP_H */
172