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 | */ |
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 | 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 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 | |
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_call_function_many(mask, func, info, wait) \ |
207 | (up_smp_call_function(func, info)) |
208 | static inline void call_function_init(void) { } |
209 | |
210 | static inline int |
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 | |
217 | static inline void kick_all_cpus_sync(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); |
224 | static inline void smp_init(void) { up_late_init(); } |
225 | #else |
226 | static inline void smp_init(void) { } |
227 | #endif |
228 | |
229 | static inline int get_boot_cpu_id(void) |
230 | { |
231 | return 0; |
232 | } |
233 | |
234 | #endif /* !SMP */ |
235 | |
236 | /** |
237 | * raw_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 | #endif /* __LINUX_SMP_H */ |
298 | |