1/* SPDX-License-Identifier: GPL-2.0 */
2#ifndef _LINUX_SCHED_TASK_H
3#define _LINUX_SCHED_TASK_H
4
5/*
6 * Interface between the scheduler and various task lifetime (fork()/exit())
7 * functionality:
8 */
9
10#include <linux/sched.h>
11
12struct task_struct;
13struct rusage;
14union thread_union;
15
16/*
17 * This serializes "schedule()" and also protects
18 * the run-queue from deletions/modifications (but
19 * _adding_ to the beginning of the run-queue has
20 * a separate lock).
21 */
22extern rwlock_t tasklist_lock;
23extern spinlock_t mmlist_lock;
24
25extern union thread_union init_thread_union;
26extern struct task_struct init_task;
27
28#ifdef CONFIG_PROVE_RCU
29extern int lockdep_tasklist_lock_is_held(void);
30#endif /* #ifdef CONFIG_PROVE_RCU */
31
32extern asmlinkage void schedule_tail(struct task_struct *prev);
33extern void init_idle(struct task_struct *idle, int cpu);
34
35extern int sched_fork(unsigned long clone_flags, struct task_struct *p);
36extern void sched_dead(struct task_struct *p);
37
38void __noreturn do_task_dead(void);
39
40extern void proc_caches_init(void);
41
42extern void release_task(struct task_struct * p);
43
44#ifdef CONFIG_HAVE_COPY_THREAD_TLS
45extern int copy_thread_tls(unsigned long, unsigned long, unsigned long,
46 struct task_struct *, unsigned long);
47#else
48extern int copy_thread(unsigned long, unsigned long, unsigned long,
49 struct task_struct *);
50
51/* Architectures that haven't opted into copy_thread_tls get the tls argument
52 * via pt_regs, so ignore the tls argument passed via C. */
53static inline int copy_thread_tls(
54 unsigned long clone_flags, unsigned long sp, unsigned long arg,
55 struct task_struct *p, unsigned long tls)
56{
57 return copy_thread(clone_flags, sp, arg, p);
58}
59#endif
60extern void flush_thread(void);
61
62#ifdef CONFIG_HAVE_EXIT_THREAD
63extern void exit_thread(struct task_struct *tsk);
64#else
65static inline void exit_thread(struct task_struct *tsk)
66{
67}
68#endif
69extern void do_group_exit(int);
70
71extern void exit_files(struct task_struct *);
72extern void exit_itimers(struct signal_struct *);
73
74extern long _do_fork(unsigned long, unsigned long, unsigned long, int __user *, int __user *, unsigned long);
75extern long do_fork(unsigned long, unsigned long, unsigned long, int __user *, int __user *);
76struct task_struct *fork_idle(int);
77extern pid_t kernel_thread(int (*fn)(void *), void *arg, unsigned long flags);
78extern long kernel_wait4(pid_t, int __user *, int, struct rusage *);
79
80extern void free_task(struct task_struct *tsk);
81
82/* sched_exec is called by processes performing an exec */
83#ifdef CONFIG_SMP
84extern void sched_exec(void);
85#else
86#define sched_exec() {}
87#endif
88
89#define get_task_struct(tsk) do { atomic_inc(&(tsk)->usage); } while(0)
90
91extern void __put_task_struct(struct task_struct *t);
92
93static inline void put_task_struct(struct task_struct *t)
94{
95 if (atomic_dec_and_test(&t->usage))
96 __put_task_struct(t);
97}
98
99struct task_struct *task_rcu_dereference(struct task_struct **ptask);
100
101#ifdef CONFIG_ARCH_WANTS_DYNAMIC_TASK_STRUCT
102extern int arch_task_struct_size __read_mostly;
103#else
104# define arch_task_struct_size (sizeof(struct task_struct))
105#endif
106
107#ifndef CONFIG_HAVE_ARCH_THREAD_STRUCT_WHITELIST
108/*
109 * If an architecture has not declared a thread_struct whitelist we
110 * must assume something there may need to be copied to userspace.
111 */
112static inline void arch_thread_struct_whitelist(unsigned long *offset,
113 unsigned long *size)
114{
115 *offset = 0;
116 /* Handle dynamically sized thread_struct. */
117 *size = arch_task_struct_size - offsetof(struct task_struct, thread);
118}
119#endif
120
121#ifdef CONFIG_VMAP_STACK
122static inline struct vm_struct *task_stack_vm_area(const struct task_struct *t)
123{
124 return t->stack_vm_area;
125}
126#else
127static inline struct vm_struct *task_stack_vm_area(const struct task_struct *t)
128{
129 return NULL;
130}
131#endif
132
133/*
134 * Protects ->fs, ->files, ->mm, ->group_info, ->comm, keyring
135 * subscriptions and synchronises with wait4(). Also used in procfs. Also
136 * pins the final release of task.io_context. Also protects ->cpuset and
137 * ->cgroup.subsys[]. And ->vfork_done.
138 *
139 * Nests both inside and outside of read_lock(&tasklist_lock).
140 * It must not be nested with write_lock_irq(&tasklist_lock),
141 * neither inside nor outside.
142 */
143static inline void task_lock(struct task_struct *p)
144{
145 spin_lock(&p->alloc_lock);
146}
147
148static inline void task_unlock(struct task_struct *p)
149{
150 spin_unlock(&p->alloc_lock);
151}
152
153#endif /* _LINUX_SCHED_TASK_H */
154