| 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 | struct 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 | */ |
| 29 | static 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 | |
| 35 | unsigned long get_state_synchronize_rcu(void); |
| 36 | |
| 37 | static inline void get_state_synchronize_rcu_full(struct rcu_gp_oldstate *rgosp) |
| 38 | { |
| 39 | rgosp->rgos_norm = get_state_synchronize_rcu(); |
| 40 | } |
| 41 | |
| 42 | unsigned long start_poll_synchronize_rcu(void); |
| 43 | |
| 44 | static inline void start_poll_synchronize_rcu_full(struct rcu_gp_oldstate *rgosp) |
| 45 | { |
| 46 | rgosp->rgos_norm = start_poll_synchronize_rcu(); |
| 47 | } |
| 48 | |
| 49 | bool poll_state_synchronize_rcu(unsigned long oldstate); |
| 50 | |
| 51 | static inline bool poll_state_synchronize_rcu_full(struct rcu_gp_oldstate *rgosp) |
| 52 | { |
| 53 | return poll_state_synchronize_rcu(rgosp->rgos_norm); |
| 54 | } |
| 55 | |
| 56 | static inline void cond_synchronize_rcu(unsigned long oldstate) |
| 57 | { |
| 58 | might_sleep(); |
| 59 | } |
| 60 | |
| 61 | static inline void cond_synchronize_rcu_full(struct rcu_gp_oldstate *rgosp) |
| 62 | { |
| 63 | cond_synchronize_rcu(rgosp->rgos_norm); |
| 64 | } |
| 65 | |
| 66 | static inline unsigned long start_poll_synchronize_rcu_expedited(void) |
| 67 | { |
| 68 | return start_poll_synchronize_rcu(); |
| 69 | } |
| 70 | |
| 71 | static 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 | |
| 76 | static inline void cond_synchronize_rcu_expedited(unsigned long oldstate) |
| 77 | { |
| 78 | cond_synchronize_rcu(oldstate); |
| 79 | } |
| 80 | |
| 81 | static inline void cond_synchronize_rcu_expedited_full(struct rcu_gp_oldstate *rgosp) |
| 82 | { |
| 83 | cond_synchronize_rcu_expedited(rgosp->rgos_norm); |
| 84 | } |
| 85 | |
| 86 | extern void rcu_barrier(void); |
| 87 | |
| 88 | static 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 | */ |
| 99 | extern void kvfree(const void *addr); |
| 100 | |
| 101 | static 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 |
| 115 | void kvfree_call_rcu(struct rcu_head *head, void *ptr); |
| 116 | #else |
| 117 | static inline void kvfree_call_rcu(struct rcu_head *head, void *ptr) |
| 118 | { |
| 119 | __kvfree_call_rcu(head, ptr); |
| 120 | } |
| 121 | #endif |
| 122 | |
| 123 | void rcu_qs(void); |
| 124 | |
| 125 | static 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 | |
| 136 | static inline int rcu_needs_cpu(void) |
| 137 | { |
| 138 | return 0; |
| 139 | } |
| 140 | |
| 141 | static 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 | */ |
| 147 | static inline void rcu_virt_note_context_switch(void) { } |
| 148 | static inline void rcu_cpu_stall_reset(void) { } |
| 149 | static inline int rcu_jiffies_till_stall_check(void) { return 21 * HZ; } |
| 150 | static inline void rcu_irq_exit_check_preempt(void) { } |
| 151 | static inline void exit_rcu(void) { } |
| 152 | static inline bool rcu_preempt_need_deferred_qs(struct task_struct *t) |
| 153 | { |
| 154 | return false; |
| 155 | } |
| 156 | static inline void rcu_preempt_deferred_qs(struct task_struct *t) { } |
| 157 | void rcu_scheduler_starting(void); |
| 158 | static inline void rcu_end_inkernel_boot(void) { } |
| 159 | static inline bool rcu_inkernel_boot_has_ended(void) { return true; } |
| 160 | static inline bool rcu_is_watching(void) { return true; } |
| 161 | static inline void rcu_momentary_dyntick_idle(void) { } |
| 162 | static inline void kfree_rcu_scheduler_running(void) { } |
| 163 | static inline bool rcu_gp_might_be_stalled(void) { return false; } |
| 164 | |
| 165 | /* Avoid RCU read-side critical sections leaking across. */ |
| 166 | static 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 |
| 174 | static inline void rcutree_report_cpu_starting(unsigned int cpu) { } |
| 175 | |
| 176 | #endif /* __LINUX_RCUTINY_H */ |