1 /* SPDX-License-Identifier: GPL-2.0+ */
2 /*
3  * Read-Copy Update mechanism for mutual exclusion, the Bloatwatch edition.
4  *
5  * Copyright IBM Corporation, 2008
6  *
7  * Author: Paul E. McKenney <paulmck@linux.ibm.com>
8  *
9  * For detailed explanation of Read-Copy Update mechanism see -
10  *		Documentation/RCU
11  */
12 #ifndef __LINUX_TINY_H
13 #define __LINUX_TINY_H
14 
15 #include <asm/param.h> /* for HZ */
16 
17 /* Never flag non-existent other CPUs! */
rcu_eqs_special_set(int cpu)18 static inline bool rcu_eqs_special_set(int cpu) { return false; }
19 
get_state_synchronize_rcu(void)20 static inline unsigned long get_state_synchronize_rcu(void)
21 {
22 	return 0;
23 }
24 
cond_synchronize_rcu(unsigned long oldstate)25 static inline void cond_synchronize_rcu(unsigned long oldstate)
26 {
27 	might_sleep();
28 }
29 
30 extern void rcu_barrier(void);
31 
synchronize_rcu_expedited(void)32 static inline void synchronize_rcu_expedited(void)
33 {
34 	synchronize_rcu();
35 }
36 
kfree_call_rcu(struct rcu_head * head,rcu_callback_t func)37 static inline void kfree_call_rcu(struct rcu_head *head, rcu_callback_t func)
38 {
39 	call_rcu(head, func);
40 }
41 
42 void rcu_qs(void);
43 
rcu_softirq_qs(void)44 static inline void rcu_softirq_qs(void)
45 {
46 	rcu_qs();
47 }
48 
49 #define rcu_note_context_switch(preempt) \
50 	do { \
51 		rcu_qs(); \
52 		rcu_tasks_qs(current); \
53 	} while (0)
54 
rcu_needs_cpu(u64 basemono,u64 * nextevt)55 static inline int rcu_needs_cpu(u64 basemono, u64 *nextevt)
56 {
57 	*nextevt = KTIME_MAX;
58 	return 0;
59 }
60 
61 /*
62  * Take advantage of the fact that there is only one CPU, which
63  * allows us to ignore virtualization-based context switches.
64  */
rcu_virt_note_context_switch(int cpu)65 static inline void rcu_virt_note_context_switch(int cpu) { }
rcu_cpu_stall_reset(void)66 static inline void rcu_cpu_stall_reset(void) { }
rcu_jiffies_till_stall_check(void)67 static inline int rcu_jiffies_till_stall_check(void) { return 21 * HZ; }
rcu_idle_enter(void)68 static inline void rcu_idle_enter(void) { }
rcu_idle_exit(void)69 static inline void rcu_idle_exit(void) { }
rcu_irq_enter(void)70 static inline void rcu_irq_enter(void) { }
rcu_irq_exit_irqson(void)71 static inline void rcu_irq_exit_irqson(void) { }
rcu_irq_enter_irqson(void)72 static inline void rcu_irq_enter_irqson(void) { }
rcu_irq_exit(void)73 static inline void rcu_irq_exit(void) { }
exit_rcu(void)74 static inline void exit_rcu(void) { }
rcu_preempt_need_deferred_qs(struct task_struct * t)75 static inline bool rcu_preempt_need_deferred_qs(struct task_struct *t)
76 {
77 	return false;
78 }
rcu_preempt_deferred_qs(struct task_struct * t)79 static inline void rcu_preempt_deferred_qs(struct task_struct *t) { }
80 #ifdef CONFIG_SRCU
81 void rcu_scheduler_starting(void);
82 #else /* #ifndef CONFIG_SRCU */
rcu_scheduler_starting(void)83 static inline void rcu_scheduler_starting(void) { }
84 #endif /* #else #ifndef CONFIG_SRCU */
rcu_end_inkernel_boot(void)85 static inline void rcu_end_inkernel_boot(void) { }
rcu_is_watching(void)86 static inline bool rcu_is_watching(void) { return true; }
87 
88 /* Avoid RCU read-side critical sections leaking across. */
rcu_all_qs(void)89 static inline void rcu_all_qs(void) { barrier(); }
90 
91 /* RCUtree hotplug events */
92 #define rcutree_prepare_cpu      NULL
93 #define rcutree_online_cpu       NULL
94 #define rcutree_offline_cpu      NULL
95 #define rcutree_dead_cpu         NULL
96 #define rcutree_dying_cpu        NULL
rcu_cpu_starting(unsigned int cpu)97 static inline void rcu_cpu_starting(unsigned int cpu) { }
98 
99 #endif /* __LINUX_RCUTINY_H */
100