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)18static inline bool rcu_eqs_special_set(int cpu) { return false; } 19 get_state_synchronize_rcu(void)20static inline unsigned long get_state_synchronize_rcu(void) 21 { 22 return 0; 23 } 24 cond_synchronize_rcu(unsigned long oldstate)25static 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)32static inline void synchronize_rcu_expedited(void) 33 { 34 synchronize_rcu(); 35 } 36 37 /* 38 * Add one more declaration of kvfree() here. It is 39 * not so straight forward to just include <linux/mm.h> 40 * where it is defined due to getting many compile 41 * errors caused by that include. 42 */ 43 extern void kvfree(const void *addr); 44 kvfree_call_rcu(struct rcu_head * head,rcu_callback_t func)45static inline void kvfree_call_rcu(struct rcu_head *head, rcu_callback_t func) 46 { 47 if (head) { 48 call_rcu(head, func); 49 return; 50 } 51 52 // kvfree_rcu(one_arg) call. 53 might_sleep(); 54 synchronize_rcu(); 55 kvfree((void *) func); 56 } 57 58 void rcu_qs(void); 59 rcu_softirq_qs(void)60static inline void rcu_softirq_qs(void) 61 { 62 rcu_qs(); 63 } 64 65 #define rcu_note_context_switch(preempt) \ 66 do { \ 67 rcu_qs(); \ 68 rcu_tasks_qs(current, (preempt)); \ 69 } while (0) 70 rcu_needs_cpu(u64 basemono,u64 * nextevt)71static inline int rcu_needs_cpu(u64 basemono, u64 *nextevt) 72 { 73 *nextevt = KTIME_MAX; 74 return 0; 75 } 76 77 /* 78 * Take advantage of the fact that there is only one CPU, which 79 * allows us to ignore virtualization-based context switches. 80 */ rcu_virt_note_context_switch(int cpu)81static inline void rcu_virt_note_context_switch(int cpu) { } rcu_cpu_stall_reset(void)82static inline void rcu_cpu_stall_reset(void) { } rcu_jiffies_till_stall_check(void)83static inline int rcu_jiffies_till_stall_check(void) { return 21 * HZ; } rcu_idle_enter(void)84static inline void rcu_idle_enter(void) { } rcu_idle_exit(void)85static inline void rcu_idle_exit(void) { } rcu_irq_enter(void)86static inline void rcu_irq_enter(void) { } rcu_irq_exit_irqson(void)87static inline void rcu_irq_exit_irqson(void) { } rcu_irq_enter_irqson(void)88static inline void rcu_irq_enter_irqson(void) { } rcu_irq_exit(void)89static inline void rcu_irq_exit(void) { } rcu_irq_exit_preempt(void)90static inline void rcu_irq_exit_preempt(void) { } rcu_irq_exit_check_preempt(void)91static inline void rcu_irq_exit_check_preempt(void) { } exit_rcu(void)92static inline void exit_rcu(void) { } rcu_preempt_need_deferred_qs(struct task_struct * t)93static inline bool rcu_preempt_need_deferred_qs(struct task_struct *t) 94 { 95 return false; 96 } rcu_preempt_deferred_qs(struct task_struct * t)97static inline void rcu_preempt_deferred_qs(struct task_struct *t) { } 98 #ifdef CONFIG_SRCU 99 void rcu_scheduler_starting(void); 100 #else /* #ifndef CONFIG_SRCU */ rcu_scheduler_starting(void)101static inline void rcu_scheduler_starting(void) { } 102 #endif /* #else #ifndef CONFIG_SRCU */ rcu_end_inkernel_boot(void)103static inline void rcu_end_inkernel_boot(void) { } rcu_inkernel_boot_has_ended(void)104static inline bool rcu_inkernel_boot_has_ended(void) { return true; } rcu_is_watching(void)105static inline bool rcu_is_watching(void) { return true; } rcu_momentary_dyntick_idle(void)106static inline void rcu_momentary_dyntick_idle(void) { } kfree_rcu_scheduler_running(void)107static inline void kfree_rcu_scheduler_running(void) { } rcu_gp_might_be_stalled(void)108static inline bool rcu_gp_might_be_stalled(void) { return false; } 109 110 /* Avoid RCU read-side critical sections leaking across. */ rcu_all_qs(void)111static inline void rcu_all_qs(void) { barrier(); } 112 113 /* RCUtree hotplug events */ 114 #define rcutree_prepare_cpu NULL 115 #define rcutree_online_cpu NULL 116 #define rcutree_offline_cpu NULL 117 #define rcutree_dead_cpu NULL 118 #define rcutree_dying_cpu NULL rcu_cpu_starting(unsigned int cpu)119static inline void rcu_cpu_starting(unsigned int cpu) { } 120 121 #endif /* __LINUX_RCUTINY_H */ 122