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#include <linux/uaccess.h>
12
13struct task_struct;
14struct rusage;
15union thread_union;
16struct css_set;
17
18/* All the bits taken by the old clone syscall. */
19#define CLONE_LEGACY_FLAGS 0xffffffffULL
20
21struct kernel_clone_args {
22 u64 flags;
23 int __user *pidfd;
24 int __user *child_tid;
25 int __user *parent_tid;
26 int exit_signal;
27 unsigned long stack;
28 unsigned long stack_size;
29 unsigned long tls;
30 pid_t *set_tid;
31 /* Number of elements in *set_tid */
32 size_t set_tid_size;
33 int cgroup;
34 int io_thread;
35 int kthread;
36 int idle;
37 int (*fn)(void *);
38 void *fn_arg;
39 struct cgroup *cgrp;
40 struct css_set *cset;
41};
42
43/*
44 * This serializes "schedule()" and also protects
45 * the run-queue from deletions/modifications (but
46 * _adding_ to the beginning of the run-queue has
47 * a separate lock).
48 */
49extern rwlock_t tasklist_lock;
50extern spinlock_t mmlist_lock;
51
52extern union thread_union init_thread_union;
53extern struct task_struct init_task;
54
55extern int lockdep_tasklist_lock_is_held(void);
56
57extern asmlinkage void schedule_tail(struct task_struct *prev);
58extern void init_idle(struct task_struct *idle, int cpu);
59
60extern int sched_fork(unsigned long clone_flags, struct task_struct *p);
61extern void sched_cgroup_fork(struct task_struct *p, struct kernel_clone_args *kargs);
62extern void sched_post_fork(struct task_struct *p);
63extern void sched_dead(struct task_struct *p);
64
65void __noreturn do_task_dead(void);
66void __noreturn make_task_dead(int signr);
67
68extern void proc_caches_init(void);
69
70extern void fork_init(void);
71
72extern void release_task(struct task_struct * p);
73
74extern int copy_thread(struct task_struct *, const struct kernel_clone_args *);
75
76extern void flush_thread(void);
77
78#ifdef CONFIG_HAVE_EXIT_THREAD
79extern void exit_thread(struct task_struct *tsk);
80#else
81static inline void exit_thread(struct task_struct *tsk)
82{
83}
84#endif
85extern __noreturn void do_group_exit(int);
86
87extern void exit_files(struct task_struct *);
88extern void exit_itimers(struct task_struct *);
89
90extern pid_t kernel_clone(struct kernel_clone_args *kargs);
91struct task_struct *create_io_thread(int (*fn)(void *), void *arg, int node);
92struct task_struct *fork_idle(int);
93struct mm_struct *copy_init_mm(void);
94extern pid_t kernel_thread(int (*fn)(void *), void *arg, unsigned long flags);
95extern pid_t user_mode_thread(int (*fn)(void *), void *arg, unsigned long flags);
96extern long kernel_wait4(pid_t, int __user *, int, struct rusage *);
97int kernel_wait(pid_t pid, int *stat);
98
99extern void free_task(struct task_struct *tsk);
100
101/* sched_exec is called by processes performing an exec */
102#ifdef CONFIG_SMP
103extern void sched_exec(void);
104#else
105#define sched_exec() {}
106#endif
107
108static inline struct task_struct *get_task_struct(struct task_struct *t)
109{
110 refcount_inc(&t->usage);
111 return t;
112}
113
114extern void __put_task_struct(struct task_struct *t);
115
116static inline void put_task_struct(struct task_struct *t)
117{
118 if (refcount_dec_and_test(&t->usage))
119 __put_task_struct(t);
120}
121
122static inline void put_task_struct_many(struct task_struct *t, int nr)
123{
124 if (refcount_sub_and_test(nr, &t->usage))
125 __put_task_struct(t);
126}
127
128void put_task_struct_rcu_user(struct task_struct *task);
129
130#ifdef CONFIG_ARCH_WANTS_DYNAMIC_TASK_STRUCT
131extern int arch_task_struct_size __read_mostly;
132#else
133# define arch_task_struct_size (sizeof(struct task_struct))
134#endif
135
136#ifndef CONFIG_HAVE_ARCH_THREAD_STRUCT_WHITELIST
137/*
138 * If an architecture has not declared a thread_struct whitelist we
139 * must assume something there may need to be copied to userspace.
140 */
141static inline void arch_thread_struct_whitelist(unsigned long *offset,
142 unsigned long *size)
143{
144 *offset = 0;
145 /* Handle dynamically sized thread_struct. */
146 *size = arch_task_struct_size - offsetof(struct task_struct, thread);
147}
148#endif
149
150#ifdef CONFIG_VMAP_STACK
151static inline struct vm_struct *task_stack_vm_area(const struct task_struct *t)
152{
153 return t->stack_vm_area;
154}
155#else
156static inline struct vm_struct *task_stack_vm_area(const struct task_struct *t)
157{
158 return NULL;
159}
160#endif
161
162/*
163 * Protects ->fs, ->files, ->mm, ->group_info, ->comm, keyring
164 * subscriptions and synchronises with wait4(). Also used in procfs. Also
165 * pins the final release of task.io_context. Also protects ->cpuset and
166 * ->cgroup.subsys[]. And ->vfork_done. And ->sysvshm.shm_clist.
167 *
168 * Nests both inside and outside of read_lock(&tasklist_lock).
169 * It must not be nested with write_lock_irq(&tasklist_lock),
170 * neither inside nor outside.
171 */
172static inline void task_lock(struct task_struct *p)
173{
174 spin_lock(&p->alloc_lock);
175}
176
177static inline void task_unlock(struct task_struct *p)
178{
179 spin_unlock(&p->alloc_lock);
180}
181
182#endif /* _LINUX_SCHED_TASK_H */
183

source code of linux/include/linux/sched/task.h