xref: /linux-6.15/include/linux/smp.h (revision 2d6ffcca)
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 init_call_single_data(void);
78 void ipi_call_lock(void);
79 void ipi_call_unlock(void);
80 void ipi_call_lock_irq(void);
81 void ipi_call_unlock_irq(void);
82 #else
83 static inline void init_call_single_data(void)
84 {
85 }
86 #endif
87 
88 /*
89  * Call a function on all processors
90  */
91 int on_each_cpu(void (*func) (void *info), void *info, int wait);
92 
93 #define MSG_ALL_BUT_SELF	0x8000	/* Assume <32768 CPU's */
94 #define MSG_ALL			0x8001
95 
96 #define MSG_INVALIDATE_TLB	0x0001	/* Remote processor TLB invalidate */
97 #define MSG_STOP_CPU		0x0002	/* Sent to shut down slave CPU's
98 					 * when rebooting
99 					 */
100 #define MSG_RESCHEDULE		0x0003	/* Reschedule request from master CPU*/
101 #define MSG_CALL_FUNCTION       0x0004  /* Call function on all other CPUs */
102 
103 /*
104  * Mark the boot cpu "online" so that it can call console drivers in
105  * printk() and can access its per-cpu storage.
106  */
107 void smp_prepare_boot_cpu(void);
108 
109 extern unsigned int setup_max_cpus;
110 
111 #else /* !SMP */
112 
113 /*
114  *	These macros fold the SMP functionality into a single CPU system
115  */
116 #define raw_smp_processor_id()			0
117 static inline int up_smp_call_function(void (*func)(void *), void *info)
118 {
119 	return 0;
120 }
121 #define smp_call_function(func, info, wait) \
122 			(up_smp_call_function(func, info))
123 #define on_each_cpu(func,info,wait)		\
124 	({					\
125 		local_irq_disable();		\
126 		func(info);			\
127 		local_irq_enable();		\
128 		0;				\
129 	})
130 static inline void smp_send_reschedule(int cpu) { }
131 #define num_booting_cpus()			1
132 #define smp_prepare_boot_cpu()			do {} while (0)
133 #define smp_call_function_single(cpuid, func, info, wait) \
134 ({ \
135 	WARN_ON(cpuid != 0);	\
136 	local_irq_disable();	\
137 	(func)(info);		\
138 	local_irq_enable();	\
139 	0;			\
140 })
141 #define smp_call_function_mask(mask, func, info, wait) \
142 			(up_smp_call_function(func, info))
143 static inline void init_call_single_data(void)
144 {
145 }
146 #endif /* !SMP */
147 
148 /*
149  * smp_processor_id(): get the current CPU ID.
150  *
151  * if DEBUG_PREEMPT is enabled the we check whether it is
152  * used in a preemption-safe way. (smp_processor_id() is safe
153  * if it's used in a preemption-off critical section, or in
154  * a thread that is bound to the current CPU.)
155  *
156  * NOTE: raw_smp_processor_id() is for internal use only
157  * (smp_processor_id() is the preferred variant), but in rare
158  * instances it might also be used to turn off false positives
159  * (i.e. smp_processor_id() use that the debugging code reports but
160  * which use for some reason is legal). Don't use this to hack around
161  * the warning message, as your code might not work under PREEMPT.
162  */
163 #ifdef CONFIG_DEBUG_PREEMPT
164   extern unsigned int debug_smp_processor_id(void);
165 # define smp_processor_id() debug_smp_processor_id()
166 #else
167 # define smp_processor_id() raw_smp_processor_id()
168 #endif
169 
170 #define get_cpu()		({ preempt_disable(); smp_processor_id(); })
171 #define put_cpu()		preempt_enable()
172 #define put_cpu_no_resched()	preempt_enable_no_resched()
173 
174 void smp_setup_processor_id(void);
175 
176 #endif /* __LINUX_SMP_H */
177