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
12 struct task_struct;
13 struct rusage;
14 union 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 */
22 extern rwlock_t tasklist_lock;
23 extern spinlock_t mmlist_lock;
24
25 extern union thread_union init_thread_union;
26 extern struct task_struct init_task;
27
28 #ifdef CONFIG_PROVE_RCU
29 extern int lockdep_tasklist_lock_is_held(void);
30 #endif /* #ifdef CONFIG_PROVE_RCU */
31
32 extern asmlinkage void schedule_tail(struct task_struct *prev);
33 extern void init_idle(struct task_struct *idle, int cpu);
34
35 extern int sched_fork(unsigned long clone_flags, struct task_struct *p);
36 extern void sched_dead(struct task_struct *p);
37
38 void __noreturn do_task_dead(void);
39 void __noreturn make_task_dead(int signr);
40
41 extern void proc_caches_init(void);
42
43 extern void fork_init(void);
44
45 extern void release_task(struct task_struct * p);
46
47 #ifdef CONFIG_HAVE_COPY_THREAD_TLS
48 extern int copy_thread_tls(unsigned long, unsigned long, unsigned long,
49 struct task_struct *, unsigned long);
50 #else
51 extern int copy_thread(unsigned long, unsigned long, unsigned long,
52 struct task_struct *);
53
54 /* Architectures that haven't opted into copy_thread_tls get the tls argument
55 * via pt_regs, so ignore the tls argument passed via C. */
copy_thread_tls(unsigned long clone_flags,unsigned long sp,unsigned long arg,struct task_struct * p,unsigned long tls)56 static inline int copy_thread_tls(
57 unsigned long clone_flags, unsigned long sp, unsigned long arg,
58 struct task_struct *p, unsigned long tls)
59 {
60 return copy_thread(clone_flags, sp, arg, p);
61 }
62 #endif
63 extern void flush_thread(void);
64
65 #ifdef CONFIG_HAVE_EXIT_THREAD
66 extern void exit_thread(struct task_struct *tsk);
67 #else
exit_thread(struct task_struct * tsk)68 static inline void exit_thread(struct task_struct *tsk)
69 {
70 }
71 #endif
72 extern void do_group_exit(int);
73
74 extern void exit_files(struct task_struct *);
75 extern void exit_itimers(struct signal_struct *);
76
77 extern long _do_fork(unsigned long, unsigned long, unsigned long, int __user *, int __user *, unsigned long);
78 extern long do_fork(unsigned long, unsigned long, unsigned long, int __user *, int __user *);
79 struct task_struct *fork_idle(int);
80 extern pid_t kernel_thread(int (*fn)(void *), void *arg, unsigned long flags);
81 extern long kernel_wait4(pid_t, int __user *, int, struct rusage *);
82
83 extern void free_task(struct task_struct *tsk);
84
85 /* sched_exec is called by processes performing an exec */
86 #ifdef CONFIG_SMP
87 extern void sched_exec(void);
88 #else
89 #define sched_exec() {}
90 #endif
91
92 #define get_task_struct(tsk) do { atomic_inc(&(tsk)->usage); } while(0)
93
94 extern void __put_task_struct(struct task_struct *t);
95
put_task_struct(struct task_struct * t)96 static inline void put_task_struct(struct task_struct *t)
97 {
98 if (atomic_dec_and_test(&t->usage))
99 __put_task_struct(t);
100 }
101
102 struct task_struct *task_rcu_dereference(struct task_struct **ptask);
103
104 #ifdef CONFIG_ARCH_WANTS_DYNAMIC_TASK_STRUCT
105 extern int arch_task_struct_size __read_mostly;
106 #else
107 # define arch_task_struct_size (sizeof(struct task_struct))
108 #endif
109
110 #ifndef CONFIG_HAVE_ARCH_THREAD_STRUCT_WHITELIST
111 /*
112 * If an architecture has not declared a thread_struct whitelist we
113 * must assume something there may need to be copied to userspace.
114 */
arch_thread_struct_whitelist(unsigned long * offset,unsigned long * size)115 static inline void arch_thread_struct_whitelist(unsigned long *offset,
116 unsigned long *size)
117 {
118 *offset = 0;
119 /* Handle dynamically sized thread_struct. */
120 *size = arch_task_struct_size - offsetof(struct task_struct, thread);
121 }
122 #endif
123
124 #ifdef CONFIG_VMAP_STACK
task_stack_vm_area(const struct task_struct * t)125 static inline struct vm_struct *task_stack_vm_area(const struct task_struct *t)
126 {
127 return t->stack_vm_area;
128 }
129 #else
task_stack_vm_area(const struct task_struct * t)130 static inline struct vm_struct *task_stack_vm_area(const struct task_struct *t)
131 {
132 return NULL;
133 }
134 #endif
135
136 /*
137 * Protects ->fs, ->files, ->mm, ->group_info, ->comm, keyring
138 * subscriptions and synchronises with wait4(). Also used in procfs. Also
139 * pins the final release of task.io_context. Also protects ->cpuset and
140 * ->cgroup.subsys[]. And ->vfork_done. And ->sysvshm.shm_clist.
141 *
142 * Nests both inside and outside of read_lock(&tasklist_lock).
143 * It must not be nested with write_lock_irq(&tasklist_lock),
144 * neither inside nor outside.
145 */
task_lock(struct task_struct * p)146 static inline void task_lock(struct task_struct *p)
147 {
148 spin_lock(&p->alloc_lock);
149 }
150
task_unlock(struct task_struct * p)151 static inline void task_unlock(struct task_struct *p)
152 {
153 spin_unlock(&p->alloc_lock);
154 }
155
156 #endif /* _LINUX_SCHED_TASK_H */
157