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 17struct rcu_gp_oldstate { 18 unsigned long rgos_norm; 19}; 20 21// Maximum number of rcu_gp_oldstate values corresponding to 22// not-yet-completed RCU grace periods. 23#define NUM_ACTIVE_RCU_POLL_FULL_OLDSTATE 2 24 25/* 26 * Are the two oldstate values the same? See the Tree RCU version for 27 * docbook header. 28 */ 29static inline bool same_state_synchronize_rcu_full(struct rcu_gp_oldstate *rgosp1, 30 struct rcu_gp_oldstate *rgosp2) 31{ 32 return rgosp1->rgos_norm == rgosp2->rgos_norm; 33} 34 35unsigned long get_state_synchronize_rcu(void); 36 37static inline void get_state_synchronize_rcu_full(struct rcu_gp_oldstate *rgosp) 38{ 39 rgosp->rgos_norm = get_state_synchronize_rcu(); 40} 41 42unsigned long start_poll_synchronize_rcu(void); 43 44static inline void start_poll_synchronize_rcu_full(struct rcu_gp_oldstate *rgosp) 45{ 46 rgosp->rgos_norm = start_poll_synchronize_rcu(); 47} 48 49bool poll_state_synchronize_rcu(unsigned long oldstate); 50 51static inline bool poll_state_synchronize_rcu_full(struct rcu_gp_oldstate *rgosp) 52{ 53 return poll_state_synchronize_rcu(rgosp->rgos_norm); 54} 55 56static inline void cond_synchronize_rcu(unsigned long oldstate) 57{ 58 might_sleep(); 59} 60 61static inline void cond_synchronize_rcu_full(struct rcu_gp_oldstate *rgosp) 62{ 63 cond_synchronize_rcu(rgosp->rgos_norm); 64} 65 66static inline unsigned long start_poll_synchronize_rcu_expedited(void) 67{ 68 return start_poll_synchronize_rcu(); 69} 70 71static inline void start_poll_synchronize_rcu_expedited_full(struct rcu_gp_oldstate *rgosp) 72{ 73 rgosp->rgos_norm = start_poll_synchronize_rcu_expedited(); 74} 75 76static inline void cond_synchronize_rcu_expedited(unsigned long oldstate) 77{ 78 cond_synchronize_rcu(oldstate); 79} 80 81static inline void cond_synchronize_rcu_expedited_full(struct rcu_gp_oldstate *rgosp) 82{ 83 cond_synchronize_rcu_expedited(rgosp->rgos_norm); 84} 85 86extern void rcu_barrier(void); 87 88static inline void synchronize_rcu_expedited(void) 89{ 90 synchronize_rcu(); 91} 92 93/* 94 * Add one more declaration of kvfree() here. It is 95 * not so straight forward to just include <linux/mm.h> 96 * where it is defined due to getting many compile 97 * errors caused by that include. 98 */ 99extern void kvfree(const void *addr); 100 101static inline void __kvfree_call_rcu(struct rcu_head *head, void *ptr) 102{ 103 if (head) { 104 call_rcu(head, (rcu_callback_t) ((void *) head - ptr)); 105 return; 106 } 107 108 // kvfree_rcu(one_arg) call. 109 might_sleep(); 110 synchronize_rcu(); 111 kvfree(ptr); 112} 113 114#ifdef CONFIG_KASAN_GENERIC 115void kvfree_call_rcu(struct rcu_head *head, void *ptr); 116#else 117static inline void kvfree_call_rcu(struct rcu_head *head, void *ptr) 118{ 119 __kvfree_call_rcu(head, ptr); 120} 121#endif 122 123void rcu_qs(void); 124 125static inline void rcu_softirq_qs(void) 126{ 127 rcu_qs(); 128} 129 130#define rcu_note_context_switch(preempt) \ 131 do { \ 132 rcu_qs(); \ 133 rcu_tasks_qs(current, (preempt)); \ 134 } while (0) 135 136static inline int rcu_needs_cpu(void) 137{ 138 return 0; 139} 140 141static inline void rcu_request_urgent_qs_task(struct task_struct *t) { } 142 143/* 144 * Take advantage of the fact that there is only one CPU, which 145 * allows us to ignore virtualization-based context switches. 146 */ 147static inline void rcu_virt_note_context_switch(void) { } 148static inline void rcu_cpu_stall_reset(void) { } 149static inline int rcu_jiffies_till_stall_check(void) { return 21 * HZ; } 150static inline void rcu_irq_exit_check_preempt(void) { } 151static inline void exit_rcu(void) { } 152static inline bool rcu_preempt_need_deferred_qs(struct task_struct *t) 153{ 154 return false; 155} 156static inline void rcu_preempt_deferred_qs(struct task_struct *t) { } 157void rcu_scheduler_starting(void); 158static inline void rcu_end_inkernel_boot(void) { } 159static inline bool rcu_inkernel_boot_has_ended(void) { return true; } 160static inline bool rcu_is_watching(void) { return true; } 161static inline void rcu_momentary_dyntick_idle(void) { } 162static inline void kfree_rcu_scheduler_running(void) { } 163static inline bool rcu_gp_might_be_stalled(void) { return false; } 164 165/* Avoid RCU read-side critical sections leaking across. */ 166static inline void rcu_all_qs(void) { barrier(); } 167 168/* RCUtree hotplug events */ 169#define rcutree_prepare_cpu NULL 170#define rcutree_online_cpu NULL 171#define rcutree_offline_cpu NULL 172#define rcutree_dead_cpu NULL 173#define rcutree_dying_cpu NULL 174static inline void rcutree_report_cpu_starting(unsigned int cpu) { } 175 176#endif /* __LINUX_RCUTINY_H */ 177