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