xref: /linux-6.15/include/linux/smp.h (revision e67f88dd)
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 #include <linux/init.h>
14 
15 extern void cpu_idle(void);
16 
17 typedef void (*smp_call_func_t)(void *info);
18 struct call_single_data {
19 	struct list_head list;
20 	smp_call_func_t func;
21 	void *info;
22 	u16 flags;
23 	u16 priv;
24 };
25 
26 /* total number of cpus in this system (may exceed NR_CPUS) */
27 extern unsigned int total_cpus;
28 
29 int smp_call_function_single(int cpuid, smp_call_func_t func, void *info,
30 			     int wait);
31 
32 #ifdef CONFIG_SMP
33 
34 #include <linux/preempt.h>
35 #include <linux/kernel.h>
36 #include <linux/compiler.h>
37 #include <linux/thread_info.h>
38 #include <asm/smp.h>
39 
40 /*
41  * main cross-CPU interfaces, handles INIT, TLB flush, STOP, etc.
42  * (defined in asm header):
43  */
44 
45 /*
46  * stops all CPUs but the current one:
47  */
48 extern void smp_send_stop(void);
49 
50 /*
51  * sends a 'reschedule' event to another CPU:
52  */
53 extern void smp_send_reschedule(int cpu);
54 
55 
56 /*
57  * Prepare machine for booting other CPUs.
58  */
59 extern void smp_prepare_cpus(unsigned int max_cpus);
60 
61 /*
62  * Bring a CPU up
63  */
64 extern int __cpu_up(unsigned int cpunum);
65 
66 /*
67  * Final polishing of CPUs
68  */
69 extern void smp_cpus_done(unsigned int max_cpus);
70 
71 /*
72  * Call a function on all other processors
73  */
74 int smp_call_function(smp_call_func_t func, void *info, int wait);
75 void smp_call_function_many(const struct cpumask *mask,
76 			    smp_call_func_t func, void *info, bool wait);
77 
78 void __smp_call_function_single(int cpuid, struct call_single_data *data,
79 				int wait);
80 
81 int smp_call_function_any(const struct cpumask *mask,
82 			  smp_call_func_t func, void *info, int wait);
83 
84 /*
85  * Generic and arch helpers
86  */
87 #ifdef CONFIG_USE_GENERIC_SMP_HELPERS
88 void generic_smp_call_function_single_interrupt(void);
89 void generic_smp_call_function_interrupt(void);
90 void ipi_call_lock(void);
91 void ipi_call_unlock(void);
92 void ipi_call_lock_irq(void);
93 void ipi_call_unlock_irq(void);
94 #endif
95 
96 /*
97  * Call a function on all processors
98  */
99 int on_each_cpu(smp_call_func_t func, void *info, int wait);
100 
101 #define MSG_ALL_BUT_SELF	0x8000	/* Assume <32768 CPU's */
102 #define MSG_ALL			0x8001
103 
104 #define MSG_INVALIDATE_TLB	0x0001	/* Remote processor TLB invalidate */
105 #define MSG_STOP_CPU		0x0002	/* Sent to shut down slave CPU's
106 					 * when rebooting
107 					 */
108 #define MSG_RESCHEDULE		0x0003	/* Reschedule request from master CPU*/
109 #define MSG_CALL_FUNCTION       0x0004  /* Call function on all other CPUs */
110 
111 /*
112  * Mark the boot cpu "online" so that it can call console drivers in
113  * printk() and can access its per-cpu storage.
114  */
115 void smp_prepare_boot_cpu(void);
116 
117 extern unsigned int setup_max_cpus;
118 extern void __init setup_nr_cpu_ids(void);
119 extern void __init smp_init(void);
120 
121 #else /* !SMP */
122 
123 static inline void smp_send_stop(void) { }
124 
125 /*
126  *	These macros fold the SMP functionality into a single CPU system
127  */
128 #define raw_smp_processor_id()			0
129 static inline int up_smp_call_function(smp_call_func_t func, void *info)
130 {
131 	return 0;
132 }
133 #define smp_call_function(func, info, wait) \
134 			(up_smp_call_function(func, info))
135 #define on_each_cpu(func,info,wait)		\
136 	({					\
137 		local_irq_disable();		\
138 		func(info);			\
139 		local_irq_enable();		\
140 		0;				\
141 	})
142 static inline void smp_send_reschedule(int cpu) { }
143 #define num_booting_cpus()			1
144 #define smp_prepare_boot_cpu()			do {} while (0)
145 #define smp_call_function_many(mask, func, info, wait) \
146 			(up_smp_call_function(func, info))
147 static inline void init_call_single_data(void) { }
148 
149 static inline int
150 smp_call_function_any(const struct cpumask *mask, smp_call_func_t func,
151 		      void *info, int wait)
152 {
153 	return smp_call_function_single(0, func, info, wait);
154 }
155 
156 #endif /* !SMP */
157 
158 /*
159  * smp_processor_id(): get the current CPU ID.
160  *
161  * if DEBUG_PREEMPT is enabled then we check whether it is
162  * used in a preemption-safe way. (smp_processor_id() is safe
163  * if it's used in a preemption-off critical section, or in
164  * a thread that is bound to the current CPU.)
165  *
166  * NOTE: raw_smp_processor_id() is for internal use only
167  * (smp_processor_id() is the preferred variant), but in rare
168  * instances it might also be used to turn off false positives
169  * (i.e. smp_processor_id() use that the debugging code reports but
170  * which use for some reason is legal). Don't use this to hack around
171  * the warning message, as your code might not work under PREEMPT.
172  */
173 #ifdef CONFIG_DEBUG_PREEMPT
174   extern unsigned int debug_smp_processor_id(void);
175 # define smp_processor_id() debug_smp_processor_id()
176 #else
177 # define smp_processor_id() raw_smp_processor_id()
178 #endif
179 
180 #define get_cpu()		({ preempt_disable(); smp_processor_id(); })
181 #define put_cpu()		preempt_enable()
182 
183 /*
184  * Callback to arch code if there's nosmp or maxcpus=0 on the
185  * boot command line:
186  */
187 extern void arch_disable_smp_support(void);
188 
189 void smp_setup_processor_id(void);
190 
191 #endif /* __LINUX_SMP_H */
192