xref: /linux-6.15/include/linux/smp.h (revision aeb3f462)
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 
11 extern void cpu_idle(void);
12 
13 #ifdef CONFIG_SMP
14 
15 #include <linux/preempt.h>
16 #include <linux/kernel.h>
17 #include <linux/compiler.h>
18 #include <linux/thread_info.h>
19 #include <asm/smp.h>
20 
21 /*
22  * main cross-CPU interfaces, handles INIT, TLB flush, STOP, etc.
23  * (defined in asm header):
24  */
25 
26 /*
27  * stops all CPUs but the current one:
28  */
29 extern void smp_send_stop(void);
30 
31 /*
32  * sends a 'reschedule' event to another CPU:
33  */
34 extern void smp_send_reschedule(int cpu);
35 
36 
37 /*
38  * Prepare machine for booting other CPUs.
39  */
40 extern void smp_prepare_cpus(unsigned int max_cpus);
41 
42 /*
43  * Bring a CPU up
44  */
45 extern int __cpu_up(unsigned int cpunum);
46 
47 /*
48  * Final polishing of CPUs
49  */
50 extern void smp_cpus_done(unsigned int max_cpus);
51 
52 /*
53  * Call a function on all other processors
54  */
55 int smp_call_function(void(*func)(void *info), void *info, int retry, int wait);
56 
57 int smp_call_function_single(int cpuid, void (*func) (void *info), void *info,
58 				int retry, int wait);
59 
60 /*
61  * Call a function on all processors
62  */
63 int on_each_cpu(void (*func) (void *info), void *info, int retry, int wait);
64 
65 #define MSG_ALL_BUT_SELF	0x8000	/* Assume <32768 CPU's */
66 #define MSG_ALL			0x8001
67 
68 #define MSG_INVALIDATE_TLB	0x0001	/* Remote processor TLB invalidate */
69 #define MSG_STOP_CPU		0x0002	/* Sent to shut down slave CPU's
70 					 * when rebooting
71 					 */
72 #define MSG_RESCHEDULE		0x0003	/* Reschedule request from master CPU*/
73 #define MSG_CALL_FUNCTION       0x0004  /* Call function on all other CPUs */
74 
75 /*
76  * Mark the boot cpu "online" so that it can call console drivers in
77  * printk() and can access its per-cpu storage.
78  */
79 void smp_prepare_boot_cpu(void);
80 
81 #else /* !SMP */
82 
83 /*
84  *	These macros fold the SMP functionality into a single CPU system
85  */
86 #define raw_smp_processor_id()			0
87 static inline int up_smp_call_function(void)
88 {
89 	return 0;
90 }
91 #define smp_call_function(func,info,retry,wait)	(up_smp_call_function())
92 #define on_each_cpu(func,info,retry,wait)	\
93 	({					\
94 		local_irq_disable();		\
95 		func(info);			\
96 		local_irq_enable();		\
97 		0;				\
98 	})
99 static inline void smp_send_reschedule(int cpu) { }
100 #define num_booting_cpus()			1
101 #define smp_prepare_boot_cpu()			do {} while (0)
102 #define smp_call_function_single(cpuid, func, info, retry, wait) \
103 ({ \
104 	WARN_ON(cpuid != 0);	\
105 	local_irq_disable();	\
106 	(func)(info);		\
107 	local_irq_enable();	\
108 	0;			\
109 })
110 
111 #endif /* !SMP */
112 
113 /*
114  * smp_processor_id(): get the current CPU ID.
115  *
116  * if DEBUG_PREEMPT is enabled the we check whether it is
117  * used in a preemption-safe way. (smp_processor_id() is safe
118  * if it's used in a preemption-off critical section, or in
119  * a thread that is bound to the current CPU.)
120  *
121  * NOTE: raw_smp_processor_id() is for internal use only
122  * (smp_processor_id() is the preferred variant), but in rare
123  * instances it might also be used to turn off false positives
124  * (i.e. smp_processor_id() use that the debugging code reports but
125  * which use for some reason is legal). Don't use this to hack around
126  * the warning message, as your code might not work under PREEMPT.
127  */
128 #ifdef CONFIG_DEBUG_PREEMPT
129   extern unsigned int debug_smp_processor_id(void);
130 # define smp_processor_id() debug_smp_processor_id()
131 #else
132 # define smp_processor_id() raw_smp_processor_id()
133 #endif
134 
135 #define get_cpu()		({ preempt_disable(); smp_processor_id(); })
136 #define put_cpu()		preempt_enable()
137 #define put_cpu_no_resched()	preempt_enable_no_resched()
138 
139 void smp_setup_processor_id(void);
140 
141 #endif /* __LINUX_SMP_H */
142