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, call_single_data_t *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 int panic_smp_redirect_cpu(int target_cpu, void *msg);
66
67 /*
68 * Call a function on all processors
69 */
on_each_cpu(smp_call_func_t func,void * info,int wait)70 static inline void on_each_cpu(smp_call_func_t func, void *info, int wait)
71 {
72 on_each_cpu_cond_mask(NULL, func, info, wait, cpu_online_mask);
73 }
74
75 /**
76 * on_each_cpu_mask(): Run a function on processors specified by
77 * cpumask, which may include the local processor.
78 * @mask: The set of cpus to run on (only runs on online subset).
79 * @func: The function to run. This must be fast and non-blocking.
80 * @info: An arbitrary pointer to pass to the function.
81 * @wait: If true, wait (atomically) until function has completed
82 * on other CPUs.
83 *
84 * If @wait is true, then returns once @func has returned.
85 *
86 * You must not call this function with disabled interrupts or from a
87 * hardware interrupt handler or from a bottom half handler. The
88 * exception is that it may be used during early boot while
89 * early_boot_irqs_disabled is set.
90 */
on_each_cpu_mask(const struct cpumask * mask,smp_call_func_t func,void * info,bool wait)91 static inline void on_each_cpu_mask(const struct cpumask *mask,
92 smp_call_func_t func, void *info, bool wait)
93 {
94 on_each_cpu_cond_mask(NULL, func, info, wait, mask);
95 }
96
97 /*
98 * Call a function on each processor for which the supplied function
99 * cond_func returns a positive value. This may include the local
100 * processor. May be used during early boot while early_boot_irqs_disabled is
101 * set. Use local_irq_save/restore() instead of local_irq_disable/enable().
102 */
on_each_cpu_cond(smp_cond_func_t cond_func,smp_call_func_t func,void * info,bool wait)103 static inline void on_each_cpu_cond(smp_cond_func_t cond_func,
104 smp_call_func_t func, void *info, bool wait)
105 {
106 on_each_cpu_cond_mask(cond_func, func, info, wait, cpu_online_mask);
107 }
108
109 /*
110 * Architecture specific boot CPU setup. Defined as empty weak function in
111 * init/main.c. Architectures can override it.
112 */
113 void __init smp_prepare_boot_cpu(void);
114
115 #ifdef CONFIG_SMP
116
117 #include <linux/preempt.h>
118 #include <linux/compiler.h>
119 #include <linux/thread_info.h>
120 #include <asm/smp.h>
121
122 /*
123 * main cross-CPU interfaces, handles INIT, TLB flush, STOP, etc.
124 * (defined in asm header):
125 */
126
127 /*
128 * stops all CPUs but the current one:
129 */
130 extern void smp_send_stop(void);
131
132 /*
133 * sends a 'reschedule' event to another CPU:
134 */
135 extern void arch_smp_send_reschedule(int cpu);
136 /*
137 * scheduler_ipi() is inline so can't be passed as callback reason, but the
138 * callsite IP should be sufficient for root-causing IPIs sent from here.
139 */
140 #define smp_send_reschedule(cpu) ({ \
141 trace_ipi_send_cpu(cpu, _RET_IP_, NULL); \
142 arch_smp_send_reschedule(cpu); \
143 })
144
145 /*
146 * Prepare machine for booting other CPUs.
147 */
148 extern void smp_prepare_cpus(unsigned int max_cpus);
149
150 /*
151 * Bring a CPU up
152 */
153 extern int __cpu_up(unsigned int cpunum, struct task_struct *tidle);
154
155 /*
156 * Final polishing of CPUs
157 */
158 extern void smp_cpus_done(unsigned int max_cpus);
159
160 /*
161 * Call a function on all other processors
162 */
163 void smp_call_function(smp_call_func_t func, void *info, int wait);
164 void smp_call_function_many(const struct cpumask *mask,
165 smp_call_func_t func, void *info, bool wait);
166
167 int smp_call_function_any(const struct cpumask *mask,
168 smp_call_func_t func, void *info, int wait);
169
170 void kick_all_cpus_sync(void);
171 void wake_up_all_idle_cpus(void);
172 bool cpus_peek_for_pending_ipi(const struct cpumask *mask);
173
174 /*
175 * Generic and arch helpers
176 */
177 void __init call_function_init(void);
178 void generic_smp_call_function_single_interrupt(void);
179 #define generic_smp_call_function_interrupt \
180 generic_smp_call_function_single_interrupt
181
182 extern unsigned int setup_max_cpus;
183 extern void __init setup_nr_cpu_ids(void);
184 extern void __init smp_init(void);
185
186 extern int __boot_cpu_id;
187
get_boot_cpu_id(void)188 static inline int get_boot_cpu_id(void)
189 {
190 return __boot_cpu_id;
191 }
192
193 #else /* !SMP */
194
smp_send_stop(void)195 static inline void smp_send_stop(void) { }
196
197 /*
198 * These macros fold the SMP functionality into a single CPU system
199 */
200 #define raw_smp_processor_id() 0
up_smp_call_function(smp_call_func_t func,void * info)201 static inline void up_smp_call_function(smp_call_func_t func, void *info)
202 {
203 }
204 #define smp_call_function(func, info, wait) \
205 (up_smp_call_function(func, info))
206
smp_send_reschedule(int cpu)207 static inline void smp_send_reschedule(int cpu) { }
208 #define smp_call_function_many(mask, func, info, wait) \
209 (up_smp_call_function(func, info))
call_function_init(void)210 static inline void call_function_init(void) { }
211
212 static inline int
smp_call_function_any(const struct cpumask * mask,smp_call_func_t func,void * info,int wait)213 smp_call_function_any(const struct cpumask *mask, smp_call_func_t func,
214 void *info, int wait)
215 {
216 return smp_call_function_single(0, func, info, wait);
217 }
218
kick_all_cpus_sync(void)219 static inline void kick_all_cpus_sync(void) { }
wake_up_all_idle_cpus(void)220 static inline void wake_up_all_idle_cpus(void) { }
cpus_peek_for_pending_ipi(const struct cpumask * mask)221 static inline bool cpus_peek_for_pending_ipi(const struct cpumask *mask)
222 {
223 return false;
224 }
225
226 #define setup_max_cpus 0
227
228 #ifdef CONFIG_UP_LATE_INIT
229 extern void __init up_late_init(void);
smp_init(void)230 static __always_inline void smp_init(void) { up_late_init(); }
231 #else
smp_init(void)232 static inline void smp_init(void) { }
233 #endif
234
get_boot_cpu_id(void)235 static inline int get_boot_cpu_id(void)
236 {
237 return 0;
238 }
239
240 #endif /* !SMP */
241
242 /**
243 * raw_smp_processor_id() - get the current (unstable) CPU id
244 *
245 * For then you know what you are doing and need an unstable
246 * CPU id.
247 */
248
249 /**
250 * smp_processor_id() - get the current (stable) CPU id
251 *
252 * This is the normal accessor to the CPU id and should be used
253 * whenever possible.
254 *
255 * The CPU id is stable when:
256 *
257 * - IRQs are disabled;
258 * - preemption is disabled;
259 * - the task is CPU affine.
260 *
261 * When CONFIG_DEBUG_PREEMPT; we verify these assumption and WARN
262 * when smp_processor_id() is used when the CPU id is not stable.
263 */
264
265 /*
266 * Allow the architecture to differentiate between a stable and unstable read.
267 * For example, x86 uses an IRQ-safe asm-volatile read for the unstable but a
268 * regular asm read for the stable.
269 */
270 #ifndef __smp_processor_id
271 #define __smp_processor_id() raw_smp_processor_id()
272 #endif
273
274 #ifdef CONFIG_DEBUG_PREEMPT
275 extern unsigned int debug_smp_processor_id(void);
276 # define smp_processor_id() debug_smp_processor_id()
277 #else
278 # define smp_processor_id() __smp_processor_id()
279 #endif
280
281 #define get_cpu() ({ preempt_disable(); __smp_processor_id(); })
282 #define put_cpu() preempt_enable()
283
284 /*
285 * Callback to arch code if there's nosmp or maxcpus=0 on the
286 * boot command line:
287 */
288 extern void arch_disable_smp_support(void);
289
290 extern void arch_thaw_secondary_cpus_begin(void);
291 extern void arch_thaw_secondary_cpus_end(void);
292
293 void smp_setup_processor_id(void);
294
295 int smp_call_on_cpu(unsigned int cpu, int (*func)(void *), void *par,
296 bool phys);
297
298 /* SMP core functions */
299 int smpcfd_prepare_cpu(unsigned int cpu);
300 int smpcfd_dead_cpu(unsigned int cpu);
301 int smpcfd_dying_cpu(unsigned int cpu);
302
303 #ifdef CONFIG_CSD_LOCK_WAIT_DEBUG
304 bool csd_lock_is_stuck(void);
305 #else
csd_lock_is_stuck(void)306 static inline bool csd_lock_is_stuck(void) { return false; }
307 #endif
308
309 #endif /* __LINUX_SMP_H */
310