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