xref: /linux-6.15/include/linux/smp.h (revision facb4edc)
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 typedef void (*smp_call_func_t)(void *info);
17 struct call_single_data {
18 	struct list_head list;
19 	smp_call_func_t func;
20 	void *info;
21 	u16 flags;
22 	u16 priv;
23 };
24 
25 /* total number of cpus in this system (may exceed NR_CPUS) */
26 extern unsigned int total_cpus;
27 
28 int smp_call_function_single(int cpuid, smp_call_func_t func, void *info,
29 			     int wait);
30 
31 #ifdef CONFIG_SMP
32 
33 #include <linux/preempt.h>
34 #include <linux/kernel.h>
35 #include <linux/compiler.h>
36 #include <linux/thread_info.h>
37 #include <asm/smp.h>
38 
39 /*
40  * main cross-CPU interfaces, handles INIT, TLB flush, STOP, etc.
41  * (defined in asm header):
42  */
43 
44 /*
45  * stops all CPUs but the current one:
46  */
47 extern void smp_send_stop(void);
48 
49 /*
50  * sends a 'reschedule' event to another CPU:
51  */
52 extern void smp_send_reschedule(int cpu);
53 
54 
55 /*
56  * Prepare machine for booting other CPUs.
57  */
58 extern void smp_prepare_cpus(unsigned int max_cpus);
59 
60 /*
61  * Bring a CPU up
62  */
63 extern int __cpu_up(unsigned int cpunum);
64 
65 /*
66  * Final polishing of CPUs
67  */
68 extern void smp_cpus_done(unsigned int max_cpus);
69 
70 /*
71  * Call a function on all other processors
72  */
73 int smp_call_function(smp_call_func_t func, void *info, int wait);
74 void smp_call_function_many(const struct cpumask *mask,
75 			    smp_call_func_t func, void *info, bool wait);
76 
77 void __smp_call_function_single(int cpuid, struct call_single_data *data,
78 				int wait);
79 
80 int smp_call_function_any(const struct cpumask *mask,
81 			  smp_call_func_t func, void *info, int wait);
82 
83 /*
84  * Generic and arch helpers
85  */
86 #ifdef CONFIG_USE_GENERIC_SMP_HELPERS
87 void generic_smp_call_function_single_interrupt(void);
88 void generic_smp_call_function_interrupt(void);
89 void ipi_call_lock(void);
90 void ipi_call_unlock(void);
91 void ipi_call_lock_irq(void);
92 void ipi_call_unlock_irq(void);
93 #endif
94 
95 /*
96  * Call a function on all processors
97  */
98 int on_each_cpu(smp_call_func_t func, void *info, int wait);
99 
100 #define MSG_ALL_BUT_SELF	0x8000	/* Assume <32768 CPU's */
101 #define MSG_ALL			0x8001
102 
103 #define MSG_INVALIDATE_TLB	0x0001	/* Remote processor TLB invalidate */
104 #define MSG_STOP_CPU		0x0002	/* Sent to shut down slave CPU's
105 					 * when rebooting
106 					 */
107 #define MSG_RESCHEDULE		0x0003	/* Reschedule request from master CPU*/
108 #define MSG_CALL_FUNCTION       0x0004  /* Call function on all other CPUs */
109 
110 /*
111  * Mark the boot cpu "online" so that it can call console drivers in
112  * printk() and can access its per-cpu storage.
113  */
114 void smp_prepare_boot_cpu(void);
115 
116 extern unsigned int setup_max_cpus;
117 
118 #else /* !SMP */
119 
120 static inline void smp_send_stop(void) { }
121 
122 /*
123  *	These macros fold the SMP functionality into a single CPU system
124  */
125 #define raw_smp_processor_id()			0
126 static inline int up_smp_call_function(smp_call_func_t func, void *info)
127 {
128 	return 0;
129 }
130 #define smp_call_function(func, info, wait) \
131 			(up_smp_call_function(func, info))
132 #define on_each_cpu(func,info,wait)		\
133 	({					\
134 		local_irq_disable();		\
135 		func(info);			\
136 		local_irq_enable();		\
137 		0;				\
138 	})
139 static inline void smp_send_reschedule(int cpu) { }
140 #define num_booting_cpus()			1
141 #define smp_prepare_boot_cpu()			do {} while (0)
142 #define smp_call_function_many(mask, func, info, wait) \
143 			(up_smp_call_function(func, info))
144 static inline void init_call_single_data(void) { }
145 
146 static inline int
147 smp_call_function_any(const struct cpumask *mask, smp_call_func_t func,
148 		      void *info, int wait)
149 {
150 	return smp_call_function_single(0, func, info, wait);
151 }
152 
153 #endif /* !SMP */
154 
155 /*
156  * smp_processor_id(): get the current CPU ID.
157  *
158  * if DEBUG_PREEMPT is enabled then we check whether it is
159  * used in a preemption-safe way. (smp_processor_id() is safe
160  * if it's used in a preemption-off critical section, or in
161  * a thread that is bound to the current CPU.)
162  *
163  * NOTE: raw_smp_processor_id() is for internal use only
164  * (smp_processor_id() is the preferred variant), but in rare
165  * instances it might also be used to turn off false positives
166  * (i.e. smp_processor_id() use that the debugging code reports but
167  * which use for some reason is legal). Don't use this to hack around
168  * the warning message, as your code might not work under PREEMPT.
169  */
170 #ifdef CONFIG_DEBUG_PREEMPT
171   extern unsigned int debug_smp_processor_id(void);
172 # define smp_processor_id() debug_smp_processor_id()
173 #else
174 # define smp_processor_id() raw_smp_processor_id()
175 #endif
176 
177 #define get_cpu()		({ preempt_disable(); smp_processor_id(); })
178 #define put_cpu()		preempt_enable()
179 
180 /*
181  * Callback to arch code if there's nosmp or maxcpus=0 on the
182  * boot command line:
183  */
184 extern void arch_disable_smp_support(void);
185 
186 void smp_setup_processor_id(void);
187 
188 #endif /* __LINUX_SMP_H */
189