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
  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
  40 extern void proc_caches_init(void);
  41
  42 extern void release_task(struct task_struct * p);
  43
  44 #ifdef CONFIG_HAVE_COPY_THREAD_TLS
  45 extern int copy_thread_tls(unsigned long, unsigned long, unsigned long,
  46                         struct task_struct *, unsigned long);
  47 #else
  48 extern 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. */
  53 static 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
  60 extern void flush_thread(void);
  61
  62 #ifdef CONFIG_HAVE_EXIT_THREAD
  63 extern void exit_thread(struct task_struct *tsk);
  64 #else
  65 static inline void exit_thread(struct task_struct *tsk)
  66 {
  67 }
  68 #endif
  69 extern void do_group_exit(int);
  70
  71 extern void exit_files(struct task_struct *);
  72 extern void exit_itimers(struct signal_struct *);
  73
  74 extern long _do_fork(unsigned long, unsigned long, unsigned long, int __user *, int __user *, unsigned long);
  75 extern long do_fork(unsigned long, unsigned long, unsigned long, int __user *, int __user *);
  76 struct task_struct *fork_idle(int);
  77 extern pid_t kernel_thread(int (*fn)(void *), void *arg, unsigned long flags);
  78 extern long kernel_wait4(pid_t, int *, int, struct rusage *);
  79
  80 extern void free_task(struct task_struct *tsk);
  81
  82 /* sched_exec is called by processes performing an exec */
  83 #ifdef CONFIG_SMP
  84 extern 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
  91 extern void __put_task_struct(struct task_struct *t);
  92
  93 static 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
  99 struct task_struct *task_rcu_dereference(struct task_struct **ptask);
 100
 101 #ifdef CONFIG_ARCH_WANTS_DYNAMIC_TASK_STRUCT
 102 extern 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  */
 112 static 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
 122 static inline struct vm_struct *task_stack_vm_area(const struct task_struct *t)
 123 {
 124         return t->stack_vm_area;
 125 }
 126 #else
 127 static 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  */
 143 static inline void task_lock(struct task_struct *p)
 144 {
 145         spin_lock(&p->alloc_lock);
 146 }
 147
 148 static inline void task_unlock(struct task_struct *p)
 149 {
 150         spin_unlock(&p->alloc_lock);
 151 }
 152
 153 #endif /* _LINUX_SCHED_TASK_H */