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