Line data Source code
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 : struct __call_single_node node;
25 : smp_call_func_t func;
26 : void *info;
27 : };
28 :
29 : #define CSD_INIT(_func, _info) \
30 : (struct __call_single_data){ .func = (_func), .info = (_info), }
31 :
32 : /* Use __aligned() to avoid to use 2 cache lines for 1 csd */
33 : typedef struct __call_single_data call_single_data_t
34 : __aligned(sizeof(struct __call_single_data));
35 :
36 : #define INIT_CSD(_csd, _func, _info) \
37 : do { \
38 : *(_csd) = CSD_INIT((_func), (_info)); \
39 : } while (0)
40 :
41 : /*
42 : * Enqueue a llist_node on the call_single_queue; be very careful, read
43 : * flush_smp_call_function_queue() in detail.
44 : */
45 : extern void __smp_call_single_queue(int cpu, struct llist_node *node);
46 :
47 : /* total number of cpus in this system (may exceed NR_CPUS) */
48 : extern unsigned int total_cpus;
49 :
50 : int smp_call_function_single(int cpuid, smp_call_func_t func, void *info,
51 : int wait);
52 :
53 : void on_each_cpu_cond_mask(smp_cond_func_t cond_func, smp_call_func_t func,
54 : void *info, bool wait, const struct cpumask *mask);
55 :
56 : int smp_call_function_single_async(int cpu, struct __call_single_data *csd);
57 :
58 : /*
59 : * Cpus stopping functions in panic. All have default weak definitions.
60 : * Architecture-dependent code may override them.
61 : */
62 : void __noreturn panic_smp_self_stop(void);
63 : void __noreturn nmi_panic_self_stop(struct pt_regs *regs);
64 : void crash_smp_send_stop(void);
65 :
66 : /*
67 : * Call a function on all processors
68 : */
69 : static inline void on_each_cpu(smp_call_func_t func, void *info, int wait)
70 : {
71 : on_each_cpu_cond_mask(NULL, func, info, wait, cpu_online_mask);
72 : }
73 :
74 : /**
75 : * on_each_cpu_mask(): Run a function on processors specified by
76 : * cpumask, which may include the local processor.
77 : * @mask: The set of cpus to run on (only runs on online subset).
78 : * @func: The function to run. This must be fast and non-blocking.
79 : * @info: An arbitrary pointer to pass to the function.
80 : * @wait: If true, wait (atomically) until function has completed
81 : * on other CPUs.
82 : *
83 : * If @wait is true, then returns once @func has returned.
84 : *
85 : * You must not call this function with disabled interrupts or from a
86 : * hardware interrupt handler or from a bottom half handler. The
87 : * exception is that it may be used during early boot while
88 : * early_boot_irqs_disabled is set.
89 : */
90 : static inline void on_each_cpu_mask(const struct cpumask *mask,
91 : smp_call_func_t func, void *info, bool wait)
92 : {
93 : on_each_cpu_cond_mask(NULL, func, info, wait, mask);
94 : }
95 :
96 : /*
97 : * Call a function on each processor for which the supplied function
98 : * cond_func returns a positive value. This may include the local
99 : * processor. May be used during early boot while early_boot_irqs_disabled is
100 : * set. Use local_irq_save/restore() instead of local_irq_disable/enable().
101 : */
102 : static inline void on_each_cpu_cond(smp_cond_func_t cond_func,
103 : smp_call_func_t func, void *info, bool wait)
104 : {
105 0 : on_each_cpu_cond_mask(cond_func, func, info, wait, cpu_online_mask);
106 : }
107 :
108 : #ifdef CONFIG_SMP
109 :
110 : #include <linux/preempt.h>
111 : #include <linux/compiler.h>
112 : #include <linux/thread_info.h>
113 : #include <asm/smp.h>
114 :
115 : /*
116 : * main cross-CPU interfaces, handles INIT, TLB flush, STOP, etc.
117 : * (defined in asm header):
118 : */
119 :
120 : /*
121 : * stops all CPUs but the current one:
122 : */
123 : extern void smp_send_stop(void);
124 :
125 : /*
126 : * sends a 'reschedule' event to another CPU:
127 : */
128 : extern void arch_smp_send_reschedule(int cpu);
129 : /*
130 : * scheduler_ipi() is inline so can't be passed as callback reason, but the
131 : * callsite IP should be sufficient for root-causing IPIs sent from here.
132 : */
133 : #define smp_send_reschedule(cpu) ({ \
134 : trace_ipi_send_cpu(cpu, _RET_IP_, NULL); \
135 : arch_smp_send_reschedule(cpu); \
136 : })
137 :
138 : /*
139 : * Prepare machine for booting other CPUs.
140 : */
141 : extern void smp_prepare_cpus(unsigned int max_cpus);
142 :
143 : /*
144 : * Bring a CPU up
145 : */
146 : extern int __cpu_up(unsigned int cpunum, struct task_struct *tidle);
147 :
148 : /*
149 : * Final polishing of CPUs
150 : */
151 : extern void smp_cpus_done(unsigned int max_cpus);
152 :
153 : /*
154 : * Call a function on all other processors
155 : */
156 : void smp_call_function(smp_call_func_t func, void *info, int wait);
157 : void smp_call_function_many(const struct cpumask *mask,
158 : smp_call_func_t func, void *info, bool wait);
159 :
160 : int smp_call_function_any(const struct cpumask *mask,
161 : smp_call_func_t func, void *info, int wait);
162 :
163 : void kick_all_cpus_sync(void);
164 : void wake_up_all_idle_cpus(void);
165 :
166 : /*
167 : * Generic and arch helpers
168 : */
169 : void __init call_function_init(void);
170 : void generic_smp_call_function_single_interrupt(void);
171 : #define generic_smp_call_function_interrupt \
172 : generic_smp_call_function_single_interrupt
173 :
174 : /*
175 : * Mark the boot cpu "online" so that it can call console drivers in
176 : * printk() and can access its per-cpu storage.
177 : */
178 : void smp_prepare_boot_cpu(void);
179 :
180 : extern unsigned int setup_max_cpus;
181 : extern void __init setup_nr_cpu_ids(void);
182 : extern void __init smp_init(void);
183 :
184 : extern int __boot_cpu_id;
185 :
186 : static inline int get_boot_cpu_id(void)
187 : {
188 : return __boot_cpu_id;
189 : }
190 :
191 : #else /* !SMP */
192 :
193 : static inline void smp_send_stop(void) { }
194 :
195 : /*
196 : * These macros fold the SMP functionality into a single CPU system
197 : */
198 : #define raw_smp_processor_id() 0
199 : static inline void up_smp_call_function(smp_call_func_t func, void *info)
200 : {
201 : }
202 : #define smp_call_function(func, info, wait) \
203 : (up_smp_call_function(func, info))
204 :
205 : static inline void smp_send_reschedule(int cpu) { }
206 : #define smp_prepare_boot_cpu() do {} while (0)
207 : #define smp_call_function_many(mask, func, info, wait) \
208 : (up_smp_call_function(func, info))
209 : static inline void call_function_init(void) { }
210 :
211 : static inline int
212 : smp_call_function_any(const struct cpumask *mask, smp_call_func_t func,
213 : void *info, int wait)
214 : {
215 : return smp_call_function_single(0, func, info, wait);
216 : }
217 :
218 : static inline void kick_all_cpus_sync(void) { }
219 : static inline void wake_up_all_idle_cpus(void) { }
220 :
221 : #ifdef CONFIG_UP_LATE_INIT
222 : extern void __init up_late_init(void);
223 : static inline void smp_init(void) { up_late_init(); }
224 : #else
225 : static inline void smp_init(void) { }
226 : #endif
227 :
228 : static inline int get_boot_cpu_id(void)
229 : {
230 : return 0;
231 : }
232 :
233 : #endif /* !SMP */
234 :
235 : /**
236 : * raw_processor_id() - get the current (unstable) CPU id
237 : *
238 : * For then you know what you are doing and need an unstable
239 : * CPU id.
240 : */
241 :
242 : /**
243 : * smp_processor_id() - get the current (stable) CPU id
244 : *
245 : * This is the normal accessor to the CPU id and should be used
246 : * whenever possible.
247 : *
248 : * The CPU id is stable when:
249 : *
250 : * - IRQs are disabled;
251 : * - preemption is disabled;
252 : * - the task is CPU affine.
253 : *
254 : * When CONFIG_DEBUG_PREEMPT; we verify these assumption and WARN
255 : * when smp_processor_id() is used when the CPU id is not stable.
256 : */
257 :
258 : /*
259 : * Allow the architecture to differentiate between a stable and unstable read.
260 : * For example, x86 uses an IRQ-safe asm-volatile read for the unstable but a
261 : * regular asm read for the stable.
262 : */
263 : #ifndef __smp_processor_id
264 : #define __smp_processor_id(x) raw_smp_processor_id(x)
265 : #endif
266 :
267 : #ifdef CONFIG_DEBUG_PREEMPT
268 : extern unsigned int debug_smp_processor_id(void);
269 : # define smp_processor_id() debug_smp_processor_id()
270 : #else
271 : # define smp_processor_id() __smp_processor_id()
272 : #endif
273 :
274 : #define get_cpu() ({ preempt_disable(); __smp_processor_id(); })
275 : #define put_cpu() preempt_enable()
276 :
277 : /*
278 : * Callback to arch code if there's nosmp or maxcpus=0 on the
279 : * boot command line:
280 : */
281 : extern void arch_disable_smp_support(void);
282 :
283 : extern void arch_thaw_secondary_cpus_begin(void);
284 : extern void arch_thaw_secondary_cpus_end(void);
285 :
286 : void smp_setup_processor_id(void);
287 :
288 : int smp_call_on_cpu(unsigned int cpu, int (*func)(void *), void *par,
289 : bool phys);
290 :
291 : /* SMP core functions */
292 : int smpcfd_prepare_cpu(unsigned int cpu);
293 : int smpcfd_dead_cpu(unsigned int cpu);
294 : int smpcfd_dying_cpu(unsigned int cpu);
295 :
296 : #endif /* __LINUX_SMP_H */
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