1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef __LINUX_SMP_H
3 #define __LINUX_SMP_H
4
5 /*
6 * Generic SMP support
7 * Alan Cox. <alan@redhat.com>
8 */
9
10 #include <linux/errno.h>
11 #include <linux/types.h>
12 #include <linux/list.h>
13 #include <linux/cpumask.h>
14 #include <linux/init.h>
15 #include <linux/smp_types.h>
16
17 typedef void (*smp_call_func_t)(void *info);
18 typedef bool (*smp_cond_func_t)(int cpu, void *info);
19
20 /*
21 * structure shares (partial) layout with struct irq_work
22 */
23 struct __call_single_data {
24 union {
25 struct __call_single_node node;
26 struct {
27 struct llist_node llist;
28 unsigned int flags;
29 #ifdef CONFIG_64BIT
30 u16 src, dst;
31 #endif
32 };
33 };
34 smp_call_func_t func;
35 void *info;
36 };
37
38 /* Use __aligned() to avoid to use 2 cache lines for 1 csd */
39 typedef struct __call_single_data call_single_data_t
40 __aligned(sizeof(struct __call_single_data));
41
42 /*
43 * Enqueue a llist_node on the call_single_queue; be very careful, read
44 * flush_smp_call_function_queue() in detail.
45 */
46 extern void __smp_call_single_queue(int cpu, struct llist_node *node);
47
48 /* total number of cpus in this system (may exceed NR_CPUS) */
49 extern unsigned int total_cpus;
50
51 int smp_call_function_single(int cpuid, smp_call_func_t func, void *info,
52 int wait);
53
54 /*
55 * Call a function on all processors
56 */
57 void on_each_cpu(smp_call_func_t func, void *info, int wait);
58
59 /*
60 * Call a function on processors specified by mask, which might include
61 * the local one.
62 */
63 void on_each_cpu_mask(const struct cpumask *mask, smp_call_func_t func,
64 void *info, bool wait);
65
66 /*
67 * Call a function on each processor for which the supplied function
68 * cond_func returns a positive value. This may include the local
69 * processor.
70 */
71 void on_each_cpu_cond(smp_cond_func_t cond_func, smp_call_func_t func,
72 void *info, bool wait);
73
74 void on_each_cpu_cond_mask(smp_cond_func_t cond_func, smp_call_func_t func,
75 void *info, bool wait, const struct cpumask *mask);
76
77 int smp_call_function_single_async(int cpu, struct __call_single_data *csd);
78
79 #ifdef CONFIG_SMP
80
81 #include <linux/preempt.h>
82 #include <linux/kernel.h>
83 #include <linux/compiler.h>
84 #include <linux/thread_info.h>
85 #include <asm/smp.h>
86
87 /*
88 * main cross-CPU interfaces, handles INIT, TLB flush, STOP, etc.
89 * (defined in asm header):
90 */
91
92 /*
93 * stops all CPUs but the current one:
94 */
95 extern void smp_send_stop(void);
96
97 /*
98 * sends a 'reschedule' event to another CPU:
99 */
100 extern void smp_send_reschedule(int cpu);
101
102
103 /*
104 * Prepare machine for booting other CPUs.
105 */
106 extern void smp_prepare_cpus(unsigned int max_cpus);
107
108 /*
109 * Bring a CPU up
110 */
111 extern int __cpu_up(unsigned int cpunum, struct task_struct *tidle);
112
113 /*
114 * Final polishing of CPUs
115 */
116 extern void smp_cpus_done(unsigned int max_cpus);
117
118 /*
119 * Call a function on all other processors
120 */
121 void smp_call_function(smp_call_func_t func, void *info, int wait);
122 void smp_call_function_many(const struct cpumask *mask,
123 smp_call_func_t func, void *info, bool wait);
124
125 int smp_call_function_any(const struct cpumask *mask,
126 smp_call_func_t func, void *info, int wait);
127
128 void kick_all_cpus_sync(void);
129 void wake_up_all_idle_cpus(void);
130 void wake_up_all_online_idle_cpus(void);
131
132 /*
133 * Generic and arch helpers
134 */
135 void __init call_function_init(void);
136 void generic_smp_call_function_single_interrupt(void);
137 #define generic_smp_call_function_interrupt \
138 generic_smp_call_function_single_interrupt
139
140 /*
141 * Mark the boot cpu "online" so that it can call console drivers in
142 * printk() and can access its per-cpu storage.
143 */
144 void smp_prepare_boot_cpu(void);
145
146 extern unsigned int setup_max_cpus;
147 extern void __init setup_nr_cpu_ids(void);
148 extern void __init smp_init(void);
149
150 extern int __boot_cpu_id;
151
get_boot_cpu_id(void)152 static inline int get_boot_cpu_id(void)
153 {
154 return __boot_cpu_id;
155 }
156
157 #else /* !SMP */
158
smp_send_stop(void)159 static inline void smp_send_stop(void) { }
160
161 /*
162 * These macros fold the SMP functionality into a single CPU system
163 */
164 #define raw_smp_processor_id() 0
up_smp_call_function(smp_call_func_t func,void * info)165 static inline void up_smp_call_function(smp_call_func_t func, void *info)
166 {
167 }
168 #define smp_call_function(func, info, wait) \
169 (up_smp_call_function(func, info))
170
smp_send_reschedule(int cpu)171 static inline void smp_send_reschedule(int cpu) { }
172 #define smp_prepare_boot_cpu() do {} while (0)
173 #define smp_call_function_many(mask, func, info, wait) \
174 (up_smp_call_function(func, info))
call_function_init(void)175 static inline void call_function_init(void) { }
176
177 static inline int
smp_call_function_any(const struct cpumask * mask,smp_call_func_t func,void * info,int wait)178 smp_call_function_any(const struct cpumask *mask, smp_call_func_t func,
179 void *info, int wait)
180 {
181 return smp_call_function_single(0, func, info, wait);
182 }
183
kick_all_cpus_sync(void)184 static inline void kick_all_cpus_sync(void) { }
wake_up_all_idle_cpus(void)185 static inline void wake_up_all_idle_cpus(void) { }
wake_up_all_online_idle_cpus(void)186 static inline void wake_up_all_online_idle_cpus(void) { }
187
188 #ifdef CONFIG_UP_LATE_INIT
189 extern void __init up_late_init(void);
smp_init(void)190 static inline void smp_init(void) { up_late_init(); }
191 #else
smp_init(void)192 static inline void smp_init(void) { }
193 #endif
194
get_boot_cpu_id(void)195 static inline int get_boot_cpu_id(void)
196 {
197 return 0;
198 }
199
200 #endif /* !SMP */
201
202 /**
203 * raw_processor_id() - get the current (unstable) CPU id
204 *
205 * For then you know what you are doing and need an unstable
206 * CPU id.
207 */
208
209 /**
210 * smp_processor_id() - get the current (stable) CPU id
211 *
212 * This is the normal accessor to the CPU id and should be used
213 * whenever possible.
214 *
215 * The CPU id is stable when:
216 *
217 * - IRQs are disabled;
218 * - preemption is disabled;
219 * - the task is CPU affine.
220 *
221 * When CONFIG_DEBUG_PREEMPT; we verify these assumption and WARN
222 * when smp_processor_id() is used when the CPU id is not stable.
223 */
224
225 /*
226 * Allow the architecture to differentiate between a stable and unstable read.
227 * For example, x86 uses an IRQ-safe asm-volatile read for the unstable but a
228 * regular asm read for the stable.
229 */
230 #ifndef __smp_processor_id
231 #define __smp_processor_id(x) raw_smp_processor_id(x)
232 #endif
233
234 #ifdef CONFIG_DEBUG_PREEMPT
235 extern unsigned int debug_smp_processor_id(void);
236 # define smp_processor_id() debug_smp_processor_id()
237 #else
238 # define smp_processor_id() __smp_processor_id()
239 #endif
240
241 #define get_cpu() ({ preempt_disable(); __smp_processor_id(); })
242 #define put_cpu() preempt_enable()
243
244 /*
245 * Callback to arch code if there's nosmp or maxcpus=0 on the
246 * boot command line:
247 */
248 extern void arch_disable_smp_support(void);
249
250 extern void arch_thaw_secondary_cpus_begin(void);
251 extern void arch_thaw_secondary_cpus_end(void);
252
253 void smp_setup_processor_id(void);
254
255 int smp_call_on_cpu(unsigned int cpu, int (*func)(void *), void *par,
256 bool phys);
257
258 /* SMP core functions */
259 int smpcfd_prepare_cpu(unsigned int cpu);
260 int smpcfd_dead_cpu(unsigned int cpu);
261 int smpcfd_dying_cpu(unsigned int cpu);
262
263 #endif /* __LINUX_SMP_H */
264