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 fork_init(void);
43
44extern void release_task(struct task_struct * p);
45
46#ifdef CONFIG_HAVE_COPY_THREAD_TLS
47extern int copy_thread_tls(unsigned long, unsigned long, unsigned long,
48 struct task_struct *, unsigned long);
49#else
50extern int copy_thread(unsigned long, unsigned long, unsigned long,
51 struct task_struct *);
52
53/* Architectures that haven't opted into copy_thread_tls get the tls argument
54 * via pt_regs, so ignore the tls argument passed via C. */
55static inline int copy_thread_tls(
56 unsigned long clone_flags, unsigned long sp, unsigned long arg,
57 struct task_struct *p, unsigned long tls)
58{
59 return copy_thread(clone_flags, sp, arg, p);
60}
61#endif
62extern void flush_thread(void);
63
64#ifdef CONFIG_HAVE_EXIT_THREAD
65extern void exit_thread(struct task_struct *tsk);
66#else
67static inline void exit_thread(struct task_struct *tsk)
68{
69}
70#endif
71extern void do_group_exit(int);
72
73extern void exit_files(struct task_struct *);
74extern void exit_itimers(struct signal_struct *);
75
76extern long _do_fork(unsigned long, unsigned long, unsigned long, int __user *, int __user *, unsigned long);
77extern long do_fork(unsigned long, unsigned long, unsigned long, int __user *, int __user *);
78struct task_struct *fork_idle(int);
79extern pid_t kernel_thread(int (*fn)(void *), void *arg, unsigned long flags);
80extern long kernel_wait4(pid_t, int __user *, int, struct rusage *);
81
82extern void free_task(struct task_struct *tsk);
83
84/* sched_exec is called by processes performing an exec */
85#ifdef CONFIG_SMP
86extern void sched_exec(void);
87#else
88#define sched_exec() {}
89#endif
90
91#define get_task_struct(tsk) do { refcount_inc(&(tsk)->usage); } while(0)
92
93extern void __put_task_struct(struct task_struct *t);
94
95static inline void put_task_struct(struct task_struct *t)
96{
97 if (refcount_dec_and_test(&t->usage))
98 __put_task_struct(t);
99}
100
101struct task_struct *task_rcu_dereference(struct task_struct **ptask);
102
103#ifdef CONFIG_ARCH_WANTS_DYNAMIC_TASK_STRUCT
104extern int arch_task_struct_size __read_mostly;
105#else
106# define arch_task_struct_size (sizeof(struct task_struct))
107#endif
108
109#ifndef CONFIG_HAVE_ARCH_THREAD_STRUCT_WHITELIST
110/*
111 * If an architecture has not declared a thread_struct whitelist we
112 * must assume something there may need to be copied to userspace.
113 */
114static inline void arch_thread_struct_whitelist(unsigned long *offset,
115 unsigned long *size)
116{
117 *offset = 0;
118 /* Handle dynamically sized thread_struct. */
119 *size = arch_task_struct_size - offsetof(struct task_struct, thread);
120}
121#endif
122
123#ifdef CONFIG_VMAP_STACK
124static inline struct vm_struct *task_stack_vm_area(const struct task_struct *t)
125{
126 return t->stack_vm_area;
127}
128#else
129static inline struct vm_struct *task_stack_vm_area(const struct task_struct *t)
130{
131 return NULL;
132}
133#endif
134
135/*
136 * Protects ->fs, ->files, ->mm, ->group_info, ->comm, keyring
137 * subscriptions and synchronises with wait4(). Also used in procfs. Also
138 * pins the final release of task.io_context. Also protects ->cpuset and
139 * ->cgroup.subsys[]. And ->vfork_done.
140 *
141 * Nests both inside and outside of read_lock(&tasklist_lock).
142 * It must not be nested with write_lock_irq(&tasklist_lock),
143 * neither inside nor outside.
144 */
145static inline void task_lock(struct task_struct *p)
146{
147 spin_lock(&p->alloc_lock);
148}
149
150static inline void task_unlock(struct task_struct *p)
151{
152 spin_unlock(&p->alloc_lock);
153}
154
155#endif /* _LINUX_SCHED_TASK_H */
156