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#include <linux/uaccess.h>
  12
  13struct task_struct;
  14struct rusage;
  15union thread_union;
  16struct css_set;
  17
  18/* All the bits taken by the old clone syscall. */
  19#define CLONE_LEGACY_FLAGS 0xffffffffULL
  20
  21struct 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        struct cgroup *cgrp;
  35        struct css_set *cset;
  36};
  37
  38/*
  39 * This serializes "schedule()" and also protects
  40 * the run-queue from deletions/modifications (but
  41 * _adding_ to the beginning of the run-queue has
  42 * a separate lock).
  43 */
  44extern rwlock_t tasklist_lock;
  45extern spinlock_t mmlist_lock;
  46
  47extern union thread_union init_thread_union;
  48extern struct task_struct init_task;
  49
  50#ifdef CONFIG_PROVE_RCU
  51extern int lockdep_tasklist_lock_is_held(void);
  52#endif /* #ifdef CONFIG_PROVE_RCU */
  53
  54extern asmlinkage void schedule_tail(struct task_struct *prev);
  55extern void init_idle(struct task_struct *idle, int cpu);
  56
  57extern int sched_fork(unsigned long clone_flags, struct task_struct *p);
  58extern void sched_dead(struct task_struct *p);
  59
  60void __noreturn do_task_dead(void);
  61
  62extern void proc_caches_init(void);
  63
  64extern void fork_init(void);
  65
  66extern void release_task(struct task_struct * p);
  67
  68#ifdef CONFIG_HAVE_COPY_THREAD_TLS
  69extern int copy_thread_tls(unsigned long, unsigned long, unsigned long,
  70                        struct task_struct *, unsigned long);
  71#else
  72extern int copy_thread(unsigned long, unsigned long, unsigned long,
  73                        struct task_struct *);
  74
  75/* Architectures that haven't opted into copy_thread_tls get the tls argument
  76 * via pt_regs, so ignore the tls argument passed via C. */
  77static inline int copy_thread_tls(
  78                unsigned long clone_flags, unsigned long sp, unsigned long arg,
  79                struct task_struct *p, unsigned long tls)
  80{
  81        return copy_thread(clone_flags, sp, arg, p);
  82}
  83#endif
  84extern void flush_thread(void);
  85
  86#ifdef CONFIG_HAVE_EXIT_THREAD
  87extern void exit_thread(struct task_struct *tsk);
  88#else
  89static inline void exit_thread(struct task_struct *tsk)
  90{
  91}
  92#endif
  93extern void do_group_exit(int);
  94
  95extern void exit_files(struct task_struct *);
  96extern void exit_itimers(struct signal_struct *);
  97
  98extern long _do_fork(struct kernel_clone_args *kargs);
  99extern bool legacy_clone_args_valid(const struct kernel_clone_args *kargs);
 100extern long do_fork(unsigned long, unsigned long, unsigned long, int __user *, int __user *);
 101struct task_struct *fork_idle(int);
 102struct mm_struct *copy_init_mm(void);
 103extern pid_t kernel_thread(int (*fn)(void *), void *arg, unsigned long flags);
 104extern long kernel_wait4(pid_t, int __user *, int, struct rusage *);
 105
 106extern void free_task(struct task_struct *tsk);
 107
 108/* sched_exec is called by processes performing an exec */
 109#ifdef CONFIG_SMP
 110extern void sched_exec(void);
 111#else
 112#define sched_exec()   {}
 113#endif
 114
 115static inline struct task_struct *get_task_struct(struct task_struct *t)
 116{
 117        refcount_inc(&t->usage);
 118        return t;
 119}
 120
 121extern void __put_task_struct(struct task_struct *t);
 122
 123static inline void put_task_struct(struct task_struct *t)
 124{
 125        if (refcount_dec_and_test(&t->usage))
 126                __put_task_struct(t);
 127}
 128
 129void put_task_struct_rcu_user(struct task_struct *task);
 130
 131#ifdef CONFIG_ARCH_WANTS_DYNAMIC_TASK_STRUCT
 132extern int arch_task_struct_size __read_mostly;
 133#else
 134# define arch_task_struct_size (sizeof(struct task_struct))
 135#endif
 136
 137#ifndef CONFIG_HAVE_ARCH_THREAD_STRUCT_WHITELIST
 138/*
 139 * If an architecture has not declared a thread_struct whitelist we
 140 * must assume something there may need to be copied to userspace.
 141 */
 142static inline void arch_thread_struct_whitelist(unsigned long *offset,
 143                                                unsigned long *size)
 144{
 145        *offset = 0;
 146        /* Handle dynamically sized thread_struct. */
 147        *size = arch_task_struct_size - offsetof(struct task_struct, thread);
 148}
 149#endif
 150
 151#ifdef CONFIG_VMAP_STACK
 152static inline struct vm_struct *task_stack_vm_area(const struct task_struct *t)
 153{
 154        return t->stack_vm_area;
 155}
 156#else
 157static inline struct vm_struct *task_stack_vm_area(const struct task_struct *t)
 158{
 159        return NULL;
 160}
 161#endif
 162
 163/*
 164 * Protects ->fs, ->files, ->mm, ->group_info, ->comm, keyring
 165 * subscriptions and synchronises with wait4().  Also used in procfs.  Also
 166 * pins the final release of task.io_context.  Also protects ->cpuset and
 167 * ->cgroup.subsys[]. And ->vfork_done.
 168 *
 169 * Nests both inside and outside of read_lock(&tasklist_lock).
 170 * It must not be nested with write_lock_irq(&tasklist_lock),
 171 * neither inside nor outside.
 172 */
 173static inline void task_lock(struct task_struct *p)
 174{
 175        spin_lock(&p->alloc_lock);
 176}
 177
 178static inline void task_unlock(struct task_struct *p)
 179{
 180        spin_unlock(&p->alloc_lock);
 181}
 182
 183#endif /* _LINUX_SCHED_TASK_H */
 184