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