LXR linux/include/linux/sched/task.h

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