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;
  16
  17/* All the bits taken by the old clone syscall. */
  18#define CLONE_LEGACY_FLAGS 0xffffffffULL
  19
  20struct kernel_clone_args {
  21        u64 flags;
  22        int __user *pidfd;
  23        int __user *child_tid;
  24        int __user *parent_tid;
  25        int exit_signal;
  26        unsigned long stack;
  27        unsigned long stack_size;
  28        unsigned long tls;
  29        pid_t *set_tid;
  30        /* Number of elements in *set_tid */
  31        size_t set_tid_size;
  32};
  33
  34/*
  35 * This serializes "schedule()" and also protects
  36 * the run-queue from deletions/modifications (but
  37 * _adding_ to the beginning of the run-queue has
  38 * a separate lock).
  39 */
  40extern rwlock_t tasklist_lock;
  41extern spinlock_t mmlist_lock;
  42
  43extern union thread_union init_thread_union;
  44extern struct task_struct init_task;
  45
  46#ifdef CONFIG_PROVE_RCU
  47extern int lockdep_tasklist_lock_is_held(void);
  48#endif /* #ifdef CONFIG_PROVE_RCU */
  49
  50extern asmlinkage void schedule_tail(struct task_struct *prev);
  51extern void init_idle(struct task_struct *idle, int cpu);
  52
  53extern int sched_fork(unsigned long clone_flags, struct task_struct *p);
  54extern void sched_dead(struct task_struct *p);
  55
  56void __noreturn do_task_dead(void);
  57
  58extern void proc_caches_init(void);
  59
  60extern void fork_init(void);
  61
  62extern void release_task(struct task_struct * p);
  63
  64#ifdef CONFIG_HAVE_COPY_THREAD_TLS
  65extern int copy_thread_tls(unsigned long, unsigned long, unsigned long,
  66                        struct task_struct *, unsigned long);
  67#else
  68extern int copy_thread(unsigned long, unsigned long, unsigned long,
  69                        struct task_struct *);
  70
  71/* Architectures that haven't opted into copy_thread_tls get the tls argument
  72 * via pt_regs, so ignore the tls argument passed via C. */
  73static inline int copy_thread_tls(
  74                unsigned long clone_flags, unsigned long sp, unsigned long arg,
  75                struct task_struct *p, unsigned long tls)
  76{
  77        return copy_thread(clone_flags, sp, arg, p);
  78}
  79#endif
  80extern void flush_thread(void);
  81
  82#ifdef CONFIG_HAVE_EXIT_THREAD
  83extern void exit_thread(struct task_struct *tsk);
  84#else
  85static inline void exit_thread(struct task_struct *tsk)
  86{
  87}
  88#endif
  89extern void do_group_exit(int);
  90
  91extern void exit_files(struct task_struct *);
  92extern void exit_itimers(struct signal_struct *);
  93
  94extern long _do_fork(struct kernel_clone_args *kargs);
  95extern bool legacy_clone_args_valid(const struct kernel_clone_args *kargs);
  96extern long do_fork(unsigned long, unsigned long, unsigned long, int __user *, int __user *);
  97struct task_struct *fork_idle(int);
  98struct mm_struct *copy_init_mm(void);
  99extern pid_t kernel_thread(int (*fn)(void *), void *arg, unsigned long flags);
 100extern long kernel_wait4(pid_t, int __user *, int, struct rusage *);
 101
 102extern void free_task(struct task_struct *tsk);
 103
 104/* sched_exec is called by processes performing an exec */
 105#ifdef CONFIG_SMP
 106extern void sched_exec(void);
 107#else
 108#define sched_exec()   {}
 109#endif
 110
 111static inline struct task_struct *get_task_struct(struct task_struct *t)
 112{
 113        refcount_inc(&t->usage);
 114        return t;
 115}
 116
 117extern void __put_task_struct(struct task_struct *t);
 118
 119static inline void put_task_struct(struct task_struct *t)
 120{
 121        if (refcount_dec_and_test(&t->usage))
 122                __put_task_struct(t);
 123}
 124
 125void put_task_struct_rcu_user(struct task_struct *task);
 126
 127#ifdef CONFIG_ARCH_WANTS_DYNAMIC_TASK_STRUCT
 128extern int arch_task_struct_size __read_mostly;
 129#else
 130# define arch_task_struct_size (sizeof(struct task_struct))
 131#endif
 132
 133#ifndef CONFIG_HAVE_ARCH_THREAD_STRUCT_WHITELIST
 134/*
 135 * If an architecture has not declared a thread_struct whitelist we
 136 * must assume something there may need to be copied to userspace.
 137 */
 138static inline void arch_thread_struct_whitelist(unsigned long *offset,
 139                                                unsigned long *size)
 140{
 141        *offset = 0;
 142        /* Handle dynamically sized thread_struct. */
 143        *size = arch_task_struct_size - offsetof(struct task_struct, thread);
 144}
 145#endif
 146
 147#ifdef CONFIG_VMAP_STACK
 148static inline struct vm_struct *task_stack_vm_area(const struct task_struct *t)
 149{
 150        return t->stack_vm_area;
 151}
 152#else
 153static inline struct vm_struct *task_stack_vm_area(const struct task_struct *t)
 154{
 155        return NULL;
 156}
 157#endif
 158
 159/*
 160 * Protects ->fs, ->files, ->mm, ->group_info, ->comm, keyring
 161 * subscriptions and synchronises with wait4().  Also used in procfs.  Also
 162 * pins the final release of task.io_context.  Also protects ->cpuset and
 163 * ->cgroup.subsys[]. And ->vfork_done.
 164 *
 165 * Nests both inside and outside of read_lock(&tasklist_lock).
 166 * It must not be nested with write_lock_irq(&tasklist_lock),
 167 * neither inside nor outside.
 168 */
 169static inline void task_lock(struct task_struct *p)
 170{
 171        spin_lock(&p->alloc_lock);
 172}
 173
 174static inline void task_unlock(struct task_struct *p)
 175{
 176        spin_unlock(&p->alloc_lock);
 177}
 178
 179#endif /* _LINUX_SCHED_TASK_H */
 180