Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
os
linux
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/llist.h>
16
17typedef void (*smp_call_func_t)(void *info);
18typedef bool (*smp_cond_func_t)(int cpu, void *info);
19
20enum {
21 CSD_FLAG_LOCK = 0x01,
22
23 /* IRQ_WORK_flags */
24
25 CSD_TYPE_ASYNC = 0x00,
26 CSD_TYPE_SYNC = 0x10,
27 CSD_TYPE_IRQ_WORK = 0x20,
28 CSD_TYPE_TTWU = 0x30,
29 CSD_FLAG_TYPE_MASK = 0xF0,
30};
31
32/*
33 * structure shares (partial) layout with struct irq_work
34 */
35struct __call_single_data {
36 struct llist_node llist;
37 unsigned int flags;
38 smp_call_func_t func;
39 void *info;
40};
41
42/* Use __aligned() to avoid to use 2 cache lines for 1 csd */
43typedef struct __call_single_data call_single_data_t
44 __aligned(sizeof(struct __call_single_data));
45
46/*
47 * Enqueue a llist_node on the call_single_queue; be very careful, read
48 * flush_smp_call_function_queue() in detail.
49 */
50extern void __smp_call_single_queue(int cpu, struct llist_node *node);
51
52/* total number of cpus in this system (may exceed NR_CPUS) */
53extern unsigned int total_cpus;
54
55int smp_call_function_single(int cpuid, smp_call_func_t func, void *info,
56 int wait);
57
58/*
59 * Call a function on all processors
60 */
61void on_each_cpu(smp_call_func_t func, void *info, int wait);
62
63/*
64 * Call a function on processors specified by mask, which might include
65 * the local one.
66 */
67void on_each_cpu_mask(const struct cpumask *mask, smp_call_func_t func,
68 void *info, bool wait);
69
70/*
71 * Call a function on each processor for which the supplied function
72 * cond_func returns a positive value. This may include the local
73 * processor.
74 */
75void on_each_cpu_cond(smp_cond_func_t cond_func, smp_call_func_t func,
76 void *info, bool wait);
77
78void on_each_cpu_cond_mask(smp_cond_func_t cond_func, smp_call_func_t func,
79 void *info, bool wait, const struct cpumask *mask);
80
81int smp_call_function_single_async(int cpu, call_single_data_t *csd);
82
83#ifdef CONFIG_SMP
84
85#include <linux/preempt.h>
86#include <linux/kernel.h>
87#include <linux/compiler.h>
88#include <linux/thread_info.h>
89#include <asm/smp.h>
90
91/*
92 * main cross-CPU interfaces, handles INIT, TLB flush, STOP, etc.
93 * (defined in asm header):
94 */
95
96/*
97 * stops all CPUs but the current one:
98 */
99extern void smp_send_stop(void);
100
101/*
102 * sends a 'reschedule' event to another CPU:
103 */
104extern void smp_send_reschedule(int cpu);
105
106
107/*
108 * Prepare machine for booting other CPUs.
109 */
110extern void smp_prepare_cpus(unsigned int max_cpus);
111
112/*
113 * Bring a CPU up
114 */
115extern int __cpu_up(unsigned int cpunum, struct task_struct *tidle);
116
117/*
118 * Final polishing of CPUs
119 */
120extern void smp_cpus_done(unsigned int max_cpus);
121
122/*
123 * Call a function on all other processors
124 */
125void smp_call_function(smp_call_func_t func, void *info, int wait);
126void smp_call_function_many(const struct cpumask *mask,
127 smp_call_func_t func, void *info, bool wait);
128
129int smp_call_function_any(const struct cpumask *mask,
130 smp_call_func_t func, void *info, int wait);
131
132void kick_all_cpus_sync(void);
133void wake_up_all_idle_cpus(void);
134
135/*
136 * Generic and arch helpers
137 */
138void __init call_function_init(void);
139void generic_smp_call_function_single_interrupt(void);
140#define generic_smp_call_function_interrupt \
141 generic_smp_call_function_single_interrupt
142
143/*
144 * Mark the boot cpu "online" so that it can call console drivers in
145 * printk() and can access its per-cpu storage.
146 */
147void smp_prepare_boot_cpu(void);
148
149extern unsigned int setup_max_cpus;
150extern void __init setup_nr_cpu_ids(void);
151extern void __init smp_init(void);
152
153extern int __boot_cpu_id;
154
155static inline int get_boot_cpu_id(void)
156{
157 return __boot_cpu_id;
158}
159
160#else /* !SMP */
161
162static inline void smp_send_stop(void) { }
163
164/*
165 * These macros fold the SMP functionality into a single CPU system
166 */
167#define raw_smp_processor_id() 0
168static inline void up_smp_call_function(smp_call_func_t func, void *info)
169{
170}
171#define smp_call_function(func, info, wait) \
172 (up_smp_call_function(func, info))
173
174static inline void smp_send_reschedule(int cpu) { }
175#define smp_prepare_boot_cpu() do {} while (0)
176#define smp_call_function_many(mask, func, info, wait) \
177 (up_smp_call_function(func, info))
178static inline void call_function_init(void) { }
179
180static inline int
181smp_call_function_any(const struct cpumask *mask, smp_call_func_t func,
182 void *info, int wait)
183{
184 return smp_call_function_single(0, func, info, wait);
185}
186
187static inline void kick_all_cpus_sync(void) { }
188static inline void wake_up_all_idle_cpus(void) { }
189
190#ifdef CONFIG_UP_LATE_INIT
191extern void __init up_late_init(void);
192static inline void smp_init(void) { up_late_init(); }
193#else
194static inline void smp_init(void) { }
195#endif
196
197static inline int get_boot_cpu_id(void)
198{
199 return 0;
200}
201
202#endif /* !SMP */
203
204/**
205 * raw_processor_id() - get the current (unstable) CPU id
206 *
207 * For then you know what you are doing and need an unstable
208 * CPU id.
209 */
210
211/**
212 * smp_processor_id() - get the current (stable) CPU id
213 *
214 * This is the normal accessor to the CPU id and should be used
215 * whenever possible.
216 *
217 * The CPU id is stable when:
218 *
219 * - IRQs are disabled;
220 * - preemption is disabled;
221 * - the task is CPU affine.
222 *
223 * When CONFIG_DEBUG_PREEMPT; we verify these assumption and WARN
224 * when smp_processor_id() is used when the CPU id is not stable.
225 */
226
227/*
228 * Allow the architecture to differentiate between a stable and unstable read.
229 * For example, x86 uses an IRQ-safe asm-volatile read for the unstable but a
230 * regular asm read for the stable.
231 */
232#ifndef __smp_processor_id
233#define __smp_processor_id(x) raw_smp_processor_id(x)
234#endif
235
236#ifdef CONFIG_DEBUG_PREEMPT
237 extern unsigned int debug_smp_processor_id(void);
238# define smp_processor_id() debug_smp_processor_id()
239#else
240# define smp_processor_id() __smp_processor_id()
241#endif
242
243#define get_cpu() ({ preempt_disable(); __smp_processor_id(); })
244#define put_cpu() preempt_enable()
245
246/*
247 * Callback to arch code if there's nosmp or maxcpus=0 on the
248 * boot command line:
249 */
250extern void arch_disable_smp_support(void);
251
252extern void arch_thaw_secondary_cpus_begin(void);
253extern void arch_thaw_secondary_cpus_end(void);
254
255void smp_setup_processor_id(void);
256
257int smp_call_on_cpu(unsigned int cpu, int (*func)(void *), void *par,
258 bool phys);
259
260/* SMP core functions */
261int smpcfd_prepare_cpu(unsigned int cpu);
262int smpcfd_dead_cpu(unsigned int cpu);
263int smpcfd_dying_cpu(unsigned int cpu);
264
265#endif /* __LINUX_SMP_H */