Line data    Source code

       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             :         int kthread;
      36             :         int idle;
      37             :         int (*fn)(void *);
      38             :         void *fn_arg;
      39             :         struct cgroup *cgrp;
      40             :         struct css_set *cset;
      41             : };
      42             : 
      43             : /*
      44             :  * This serializes "schedule()" and also protects
      45             :  * the run-queue from deletions/modifications (but
      46             :  * _adding_ to the beginning of the run-queue has
      47             :  * a separate lock).
      48             :  */
      49             : extern rwlock_t tasklist_lock;
      50             : extern spinlock_t mmlist_lock;
      51             : 
      52             : extern union thread_union init_thread_union;
      53             : extern struct task_struct init_task;
      54             : 
      55             : extern int lockdep_tasklist_lock_is_held(void);
      56             : 
      57             : extern asmlinkage void schedule_tail(struct task_struct *prev);
      58             : extern void init_idle(struct task_struct *idle, int cpu);
      59             : 
      60             : extern int sched_fork(unsigned long clone_flags, struct task_struct *p);
      61             : extern void sched_cgroup_fork(struct task_struct *p, struct kernel_clone_args *kargs);
      62             : extern void sched_post_fork(struct task_struct *p);
      63             : extern void sched_dead(struct task_struct *p);
      64             : 
      65             : void __noreturn do_task_dead(void);
      66             : void __noreturn make_task_dead(int signr);
      67             : 
      68             : extern void mm_cache_init(void);
      69             : extern void proc_caches_init(void);
      70             : 
      71             : extern void fork_init(void);
      72             : 
      73             : extern void release_task(struct task_struct * p);
      74             : 
      75             : extern int copy_thread(struct task_struct *, const struct kernel_clone_args *);
      76             : 
      77             : extern void flush_thread(void);
      78             : 
      79             : #ifdef CONFIG_HAVE_EXIT_THREAD
      80             : extern void exit_thread(struct task_struct *tsk);
      81             : #else
      82             : static inline void exit_thread(struct task_struct *tsk)
      83             : {
      84             : }
      85             : #endif
      86             : extern __noreturn void do_group_exit(int);
      87             : 
      88             : extern void exit_files(struct task_struct *);
      89             : extern void exit_itimers(struct task_struct *);
      90             : 
      91             : extern pid_t kernel_clone(struct kernel_clone_args *kargs);
      92             : struct task_struct *create_io_thread(int (*fn)(void *), void *arg, int node);
      93             : struct task_struct *fork_idle(int);
      94             : extern pid_t kernel_thread(int (*fn)(void *), void *arg, unsigned long flags);
      95             : extern pid_t user_mode_thread(int (*fn)(void *), void *arg, unsigned long flags);
      96             : extern long kernel_wait4(pid_t, int __user *, int, struct rusage *);
      97             : int kernel_wait(pid_t pid, int *stat);
      98             : 
      99             : extern void free_task(struct task_struct *tsk);
     100             : 
     101             : /* sched_exec is called by processes performing an exec */
     102             : #ifdef CONFIG_SMP
     103             : extern void sched_exec(void);
     104             : #else
     105             : #define sched_exec()   {}
     106             : #endif
     107             : 
     108             : static inline struct task_struct *get_task_struct(struct task_struct *t)
     109             : {
     110           2 :         refcount_inc(&t->usage);
     111             :         return t;
     112             : }
     113             : 
     114             : extern void __put_task_struct(struct task_struct *t);
     115             : 
     116         332 : static inline void put_task_struct(struct task_struct *t)
     117             : {
     118         664 :         if (refcount_dec_and_test(&t->usage))
     119         332 :                 __put_task_struct(t);
     120         332 : }
     121             : 
     122           0 : static inline void put_task_struct_many(struct task_struct *t, int nr)
     123             : {
     124           0 :         if (refcount_sub_and_test(nr, &t->usage))
     125           0 :                 __put_task_struct(t);
     126           0 : }
     127             : 
     128             : void put_task_struct_rcu_user(struct task_struct *task);
     129             : 
     130             : /* Free all architecture-specific resources held by a thread. */
     131             : void release_thread(struct task_struct *dead_task);
     132             : 
     133             : #ifdef CONFIG_ARCH_WANTS_DYNAMIC_TASK_STRUCT
     134             : extern int arch_task_struct_size __read_mostly;
     135             : #else
     136             : # define arch_task_struct_size (sizeof(struct task_struct))
     137             : #endif
     138             : 
     139             : #ifndef CONFIG_HAVE_ARCH_THREAD_STRUCT_WHITELIST
     140             : /*
     141             :  * If an architecture has not declared a thread_struct whitelist we
     142             :  * must assume something there may need to be copied to userspace.
     143             :  */
     144             : static inline void arch_thread_struct_whitelist(unsigned long *offset,
     145             :                                                 unsigned long *size)
     146             : {
     147           1 :         *offset = 0;
     148             :         /* Handle dynamically sized thread_struct. */
     149           1 :         *size = arch_task_struct_size - offsetof(struct task_struct, thread);
     150             : }
     151             : #endif
     152             : 
     153             : #ifdef CONFIG_VMAP_STACK
     154             : static inline struct vm_struct *task_stack_vm_area(const struct task_struct *t)
     155             : {
     156             :         return t->stack_vm_area;
     157             : }
     158             : #else
     159             : static inline struct vm_struct *task_stack_vm_area(const struct task_struct *t)
     160             : {
     161             :         return NULL;
     162             : }
     163             : #endif
     164             : 
     165             : /*
     166             :  * Protects ->fs, ->files, ->mm, ->group_info, ->comm, keyring
     167             :  * subscriptions and synchronises with wait4().  Also used in procfs.  Also
     168             :  * pins the final release of task.io_context.  Also protects ->cpuset and
     169             :  * ->cgroup.subsys[]. And ->vfork_done. And ->sysvshm.shm_clist.
     170             :  *
     171             :  * Nests both inside and outside of read_lock(&tasklist_lock).
     172             :  * It must not be nested with write_lock_irq(&tasklist_lock),
     173             :  * neither inside nor outside.
     174             :  */
     175             : static inline void task_lock(struct task_struct *p)
     176             : {
     177        4084 :         spin_lock(&p->alloc_lock);
     178             : }
     179             : 
     180             : static inline void task_unlock(struct task_struct *p)
     181             : {
     182        4084 :         spin_unlock(&p->alloc_lock);
     183             : }
     184             : 
     185             : #endif /* _LINUX_SCHED_TASK_H */