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
66 /*
67 * Call a function on all processors
68 */
on_each_cpu(smp_call_func_t func,void * info,int wait)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 */
on_each_cpu_mask(const struct cpumask * mask,smp_call_func_t func,void * info,bool wait)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 */
on_each_cpu_cond(smp_cond_func_t cond_func,smp_call_func_t func,void * info,bool wait)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 on_each_cpu_cond_mask(cond_func, func, info, wait, cpu_online_mask);
106 }
107
108 /*
109 * Architecture specific boot CPU setup. Defined as empty weak function in
110 * init/main.c. Architectures can override it.
111 */
112 void __init smp_prepare_boot_cpu(void);
113
114 #ifdef CONFIG_SMP
115
116 #include <linux/preempt.h>
117 #include <linux/compiler.h>
118 #include <linux/thread_info.h>
119 #include <asm/smp.h>
120
121 /*
122 * main cross-CPU interfaces, handles INIT, TLB flush, STOP, etc.
123 * (defined in asm header):
124 */
125
126 /*
127 * stops all CPUs but the current one:
128 */
129 extern void smp_send_stop(void);
130
131 /*
132 * sends a 'reschedule' event to another CPU:
133 */
134 extern void arch_smp_send_reschedule(int cpu);
135 /*
136 * scheduler_ipi() is inline so can't be passed as callback reason, but the
137 * callsite IP should be sufficient for root-causing IPIs sent from here.
138 */
139 #define smp_send_reschedule(cpu) ({ \
140 trace_ipi_send_cpu(cpu, _RET_IP_, NULL); \
141 arch_smp_send_reschedule(cpu); \
142 })
143
144 /*
145 * Prepare machine for booting other CPUs.
146 */
147 extern void smp_prepare_cpus(unsigned int max_cpus);
148
149 /*
150 * Bring a CPU up
151 */
152 extern int __cpu_up(unsigned int cpunum, struct task_struct *tidle);
153
154 /*
155 * Final polishing of CPUs
156 */
157 extern void smp_cpus_done(unsigned int max_cpus);
158
159 /*
160 * Call a function on all other processors
161 */
162 void smp_call_function(smp_call_func_t func, void *info, int wait);
163 void smp_call_function_many(const struct cpumask *mask,
164 smp_call_func_t func, void *info, bool wait);
165
166 int smp_call_function_any(const struct cpumask *mask,
167 smp_call_func_t func, void *info, int wait);
168
169 void kick_all_cpus_sync(void);
170 void wake_up_all_idle_cpus(void);
171
172 /*
173 * Generic and arch helpers
174 */
175 void __init call_function_init(void);
176 void generic_smp_call_function_single_interrupt(void);
177 #define generic_smp_call_function_interrupt \
178 generic_smp_call_function_single_interrupt
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
get_boot_cpu_id(void)186 static inline int get_boot_cpu_id(void)
187 {
188 return __boot_cpu_id;
189 }
190
191 #else /* !SMP */
192
smp_send_stop(void)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
up_smp_call_function(smp_call_func_t func,void * info)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
smp_send_reschedule(int cpu)205 static inline void smp_send_reschedule(int cpu) { }
206 #define smp_call_function_many(mask, func, info, wait) \
207 (up_smp_call_function(func, info))
call_function_init(void)208 static inline void call_function_init(void) { }
209
210 static inline int
smp_call_function_any(const struct cpumask * mask,smp_call_func_t func,void * info,int wait)211 smp_call_function_any(const struct cpumask *mask, smp_call_func_t func,
212 void *info, int wait)
213 {
214 return smp_call_function_single(0, func, info, wait);
215 }
216
kick_all_cpus_sync(void)217 static inline void kick_all_cpus_sync(void) { }
wake_up_all_idle_cpus(void)218 static inline void wake_up_all_idle_cpus(void) { }
219
220 #define setup_max_cpus 0
221
222 #ifdef CONFIG_UP_LATE_INIT
223 extern void __init up_late_init(void);
smp_init(void)224 static __always_inline void smp_init(void) { up_late_init(); }
225 #else
smp_init(void)226 static inline void smp_init(void) { }
227 #endif
228
get_boot_cpu_id(void)229 static inline int get_boot_cpu_id(void)
230 {
231 return 0;
232 }
233
234 #endif /* !SMP */
235
236 /**
237 * raw_smp_processor_id() - get the current (unstable) CPU id
238 *
239 * For then you know what you are doing and need an unstable
240 * CPU id.
241 */
242
243 /**
244 * smp_processor_id() - get the current (stable) CPU id
245 *
246 * This is the normal accessor to the CPU id and should be used
247 * whenever possible.
248 *
249 * The CPU id is stable when:
250 *
251 * - IRQs are disabled;
252 * - preemption is disabled;
253 * - the task is CPU affine.
254 *
255 * When CONFIG_DEBUG_PREEMPT; we verify these assumption and WARN
256 * when smp_processor_id() is used when the CPU id is not stable.
257 */
258
259 /*
260 * Allow the architecture to differentiate between a stable and unstable read.
261 * For example, x86 uses an IRQ-safe asm-volatile read for the unstable but a
262 * regular asm read for the stable.
263 */
264 #ifndef __smp_processor_id
265 #define __smp_processor_id() raw_smp_processor_id()
266 #endif
267
268 #ifdef CONFIG_DEBUG_PREEMPT
269 extern unsigned int debug_smp_processor_id(void);
270 # define smp_processor_id() debug_smp_processor_id()
271 #else
272 # define smp_processor_id() __smp_processor_id()
273 #endif
274
275 #define get_cpu() ({ preempt_disable(); __smp_processor_id(); })
276 #define put_cpu() preempt_enable()
277
278 /*
279 * Callback to arch code if there's nosmp or maxcpus=0 on the
280 * boot command line:
281 */
282 extern void arch_disable_smp_support(void);
283
284 extern void arch_thaw_secondary_cpus_begin(void);
285 extern void arch_thaw_secondary_cpus_end(void);
286
287 void smp_setup_processor_id(void);
288
289 int smp_call_on_cpu(unsigned int cpu, int (*func)(void *), void *par,
290 bool phys);
291
292 /* SMP core functions */
293 int smpcfd_prepare_cpu(unsigned int cpu);
294 int smpcfd_dead_cpu(unsigned int cpu);
295 int smpcfd_dying_cpu(unsigned int cpu);
296
297 #ifdef CONFIG_CSD_LOCK_WAIT_DEBUG
298 bool csd_lock_is_stuck(void);
299 #else
csd_lock_is_stuck(void)300 static inline bool csd_lock_is_stuck(void) { return false; }
301 #endif
302
303 #endif /* __LINUX_SMP_H */
304