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 unsigned long get_state_synchronize_rcu(void); 18 unsigned long start_poll_synchronize_rcu(void); 19 bool poll_state_synchronize_rcu(unsigned long oldstate); 20 cond_synchronize_rcu(unsigned long oldstate)21static inline void cond_synchronize_rcu(unsigned long oldstate) 22 { 23 might_sleep(); 24 } 25 26 extern void rcu_barrier(void); 27 synchronize_rcu_expedited(void)28static inline void synchronize_rcu_expedited(void) 29 { 30 synchronize_rcu(); 31 } 32 33 /* 34 * Add one more declaration of kvfree() here. It is 35 * not so straight forward to just include <linux/mm.h> 36 * where it is defined due to getting many compile 37 * errors caused by that include. 38 */ 39 extern void kvfree(const void *addr); 40 kvfree_call_rcu(struct rcu_head * head,rcu_callback_t func)41static inline void kvfree_call_rcu(struct rcu_head *head, rcu_callback_t func) 42 { 43 if (head) { 44 call_rcu(head, func); 45 return; 46 } 47 48 // kvfree_rcu(one_arg) call. 49 might_sleep(); 50 synchronize_rcu(); 51 kvfree((void *) func); 52 } 53 54 void rcu_qs(void); 55 rcu_softirq_qs(void)56static inline void rcu_softirq_qs(void) 57 { 58 rcu_qs(); 59 } 60 61 #define rcu_note_context_switch(preempt) \ 62 do { \ 63 rcu_qs(); \ 64 rcu_tasks_qs(current, (preempt)); \ 65 } while (0) 66 rcu_needs_cpu(u64 basemono,u64 * nextevt)67static inline int rcu_needs_cpu(u64 basemono, u64 *nextevt) 68 { 69 *nextevt = KTIME_MAX; 70 return 0; 71 } 72 73 /* 74 * Take advantage of the fact that there is only one CPU, which 75 * allows us to ignore virtualization-based context switches. 76 */ rcu_virt_note_context_switch(int cpu)77static inline void rcu_virt_note_context_switch(int cpu) { } rcu_cpu_stall_reset(void)78static inline void rcu_cpu_stall_reset(void) { } rcu_jiffies_till_stall_check(void)79static inline int rcu_jiffies_till_stall_check(void) { return 21 * HZ; } rcu_idle_enter(void)80static inline void rcu_idle_enter(void) { } rcu_idle_exit(void)81static inline void rcu_idle_exit(void) { } rcu_irq_enter(void)82static inline void rcu_irq_enter(void) { } rcu_irq_exit_irqson(void)83static inline void rcu_irq_exit_irqson(void) { } rcu_irq_enter_irqson(void)84static inline void rcu_irq_enter_irqson(void) { } rcu_irq_exit(void)85static inline void rcu_irq_exit(void) { } rcu_irq_exit_check_preempt(void)86static inline void rcu_irq_exit_check_preempt(void) { } 87 #define rcu_is_idle_cpu(cpu) \ 88 (is_idle_task(current) && !in_nmi() && !in_irq() && !in_serving_softirq()) exit_rcu(void)89static inline void exit_rcu(void) { } rcu_preempt_need_deferred_qs(struct task_struct * t)90static inline bool rcu_preempt_need_deferred_qs(struct task_struct *t) 91 { 92 return false; 93 } rcu_preempt_deferred_qs(struct task_struct * t)94static inline void rcu_preempt_deferred_qs(struct task_struct *t) { } 95 #ifdef CONFIG_SRCU 96 void rcu_scheduler_starting(void); 97 #else /* #ifndef CONFIG_SRCU */ rcu_scheduler_starting(void)98static inline void rcu_scheduler_starting(void) { } 99 #endif /* #else #ifndef CONFIG_SRCU */ rcu_end_inkernel_boot(void)100static inline void rcu_end_inkernel_boot(void) { } rcu_inkernel_boot_has_ended(void)101static inline bool rcu_inkernel_boot_has_ended(void) { return true; } rcu_is_watching(void)102static inline bool rcu_is_watching(void) { return true; } rcu_momentary_dyntick_idle(void)103static inline void rcu_momentary_dyntick_idle(void) { } kfree_rcu_scheduler_running(void)104static inline void kfree_rcu_scheduler_running(void) { } rcu_gp_might_be_stalled(void)105static inline bool rcu_gp_might_be_stalled(void) { return false; } 106 107 /* Avoid RCU read-side critical sections leaking across. */ rcu_all_qs(void)108static inline void rcu_all_qs(void) { barrier(); } 109 110 /* RCUtree hotplug events */ 111 #define rcutree_prepare_cpu NULL 112 #define rcutree_online_cpu NULL 113 #define rcutree_offline_cpu NULL 114 #define rcutree_dead_cpu NULL 115 #define rcutree_dying_cpu NULL rcu_cpu_starting(unsigned int cpu)116static inline void rcu_cpu_starting(unsigned int cpu) { } 117 118 #endif /* __LINUX_RCUTINY_H */ 119