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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! */
18static inline bool rcu_eqs_special_set(int cpu) { return false; }
19
20static inline unsigned long get_state_synchronize_rcu(void)
21{
22 return 0;
23}
24
25static inline void cond_synchronize_rcu(unsigned long oldstate)
26{
27 might_sleep();
28}
29
30extern void rcu_barrier(void);
31
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 */
43extern void kvfree(const void *addr);
44
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
58void rcu_qs(void);
59
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
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 */
81static inline void rcu_virt_note_context_switch(int cpu) { }
82static inline void rcu_cpu_stall_reset(void) { }
83static inline int rcu_jiffies_till_stall_check(void) { return 21 * HZ; }
84static inline void rcu_idle_enter(void) { }
85static inline void rcu_idle_exit(void) { }
86static inline void rcu_irq_enter(void) { }
87static inline void rcu_irq_exit_irqson(void) { }
88static inline void rcu_irq_enter_irqson(void) { }
89static inline void rcu_irq_exit(void) { }
90static inline void rcu_irq_exit_preempt(void) { }
91static inline void rcu_irq_exit_check_preempt(void) { }
92static inline void exit_rcu(void) { }
93static inline bool rcu_preempt_need_deferred_qs(struct task_struct *t)
94{
95 return false;
96}
97static inline void rcu_preempt_deferred_qs(struct task_struct *t) { }
98#ifdef CONFIG_SRCU
99void rcu_scheduler_starting(void);
100#else /* #ifndef CONFIG_SRCU */
101static inline void rcu_scheduler_starting(void) { }
102#endif /* #else #ifndef CONFIG_SRCU */
103static inline void rcu_end_inkernel_boot(void) { }
104static inline bool rcu_inkernel_boot_has_ended(void) { return true; }
105static inline bool rcu_is_watching(void) { return true; }
106static inline bool __rcu_is_watching(void) { return true; }
107static inline void rcu_momentary_dyntick_idle(void) { }
108static inline void kfree_rcu_scheduler_running(void) { }
109static inline bool rcu_gp_might_be_stalled(void) { return false; }
110
111/* Avoid RCU read-side critical sections leaking across. */
112static inline void rcu_all_qs(void) { barrier(); }
113
114/* RCUtree hotplug events */
115#define rcutree_prepare_cpu NULL
116#define rcutree_online_cpu NULL
117#define rcutree_offline_cpu NULL
118#define rcutree_dead_cpu NULL
119#define rcutree_dying_cpu NULL
120static inline void rcu_cpu_starting(unsigned int cpu) { }
121
122#endif /* __LINUX_RCUTINY_H */
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 */