root/include/linux/sched/task.h

INCLUDED FROM

DEFINITIONS

1. copy_thread_tls
2. exit_thread
3. get_task_struct
4. put_task_struct
5. arch_thread_struct_whitelist
6. task_stack_vm_area
7. task_stack_vm_area
8. task_lock
9. task_unlock

   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 
  17 /* All the bits taken by the old clone syscall. */
  18 #define CLONE_LEGACY_FLAGS 0xffffffffULL
  19 
  20 struct 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  */
  37 extern rwlock_t tasklist_lock;
  38 extern spinlock_t mmlist_lock;
  39 
  40 extern union thread_union init_thread_union;
  41 extern struct task_struct init_task;
  42 
  43 #ifdef CONFIG_PROVE_RCU
  44 extern int lockdep_tasklist_lock_is_held(void);
  45 #endif /* #ifdef CONFIG_PROVE_RCU */
  46 
  47 extern asmlinkage void schedule_tail(struct task_struct *prev);
  48 extern void init_idle(struct task_struct *idle, int cpu);
  49 
  50 extern int sched_fork(unsigned long clone_flags, struct task_struct *p);
  51 extern void sched_dead(struct task_struct *p);
  52 
  53 void __noreturn do_task_dead(void);
  54 
  55 extern void proc_caches_init(void);
  56 
  57 extern void fork_init(void);
  58 
  59 extern void release_task(struct task_struct * p);
  60 
  61 #ifdef CONFIG_HAVE_COPY_THREAD_TLS
  62 extern int copy_thread_tls(unsigned long, unsigned long, unsigned long,
  63                         struct task_struct *, unsigned long);
  64 #else
  65 extern 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. */
  70 static 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
  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 void do_group_exit(int);
  87 
  88 extern void exit_files(struct task_struct *);
  89 extern void exit_itimers(struct signal_struct *);
  90 
  91 extern long _do_fork(struct kernel_clone_args *kargs);
  92 extern bool legacy_clone_args_valid(const struct kernel_clone_args *kargs);
  93 extern long do_fork(unsigned long, unsigned long, unsigned long, int __user *, int __user *);
  94 struct task_struct *fork_idle(int);
  95 struct mm_struct *copy_init_mm(void);
  96 extern pid_t kernel_thread(int (*fn)(void *), void *arg, unsigned long flags);
  97 extern long kernel_wait4(pid_t, int __user *, int, struct rusage *);
  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         refcount_inc(&t->usage);
 111         return t;
 112 }
 113 
 114 extern void __put_task_struct(struct task_struct *t);
 115 
 116 static inline void put_task_struct(struct task_struct *t)
 117 {
 118         if (refcount_dec_and_test(&t->usage))
 119                 __put_task_struct(t);
 120 }
 121 
 122 void put_task_struct_rcu_user(struct task_struct *task);
 123 
 124 #ifdef CONFIG_ARCH_WANTS_DYNAMIC_TASK_STRUCT
 125 extern int arch_task_struct_size __read_mostly;
 126 #else
 127 # define arch_task_struct_size (sizeof(struct task_struct))
 128 #endif
 129 
 130 #ifndef CONFIG_HAVE_ARCH_THREAD_STRUCT_WHITELIST
 131 /*
 132  * If an architecture has not declared a thread_struct whitelist we
 133  * must assume something there may need to be copied to userspace.
 134  */
 135 static inline void arch_thread_struct_whitelist(unsigned long *offset,
 136                                                 unsigned long *size)
 137 {
 138         *offset = 0;
 139         /* Handle dynamically sized thread_struct. */
 140         *size = arch_task_struct_size - offsetof(struct task_struct, thread);
 141 }
 142 #endif
 143 
 144 #ifdef CONFIG_VMAP_STACK
 145 static inline struct vm_struct *task_stack_vm_area(const struct task_struct *t)
 146 {
 147         return t->stack_vm_area;
 148 }
 149 #else
 150 static inline struct vm_struct *task_stack_vm_area(const struct task_struct *t)
 151 {
 152         return NULL;
 153 }
 154 #endif
 155 
 156 /*
 157  * Protects ->fs, ->files, ->mm, ->group_info, ->comm, keyring
 158  * subscriptions and synchronises with wait4().  Also used in procfs.  Also
 159  * pins the final release of task.io_context.  Also protects ->cpuset and
 160  * ->cgroup.subsys[]. And ->vfork_done.
 161  *
 162  * Nests both inside and outside of read_lock(&tasklist_lock).
 163  * It must not be nested with write_lock_irq(&tasklist_lock),
 164  * neither inside nor outside.
 165  */
 166 static inline void task_lock(struct task_struct *p)
 167 {
 168         spin_lock(&p->alloc_lock);
 169 }
 170 
 171 static inline void task_unlock(struct task_struct *p)
 172 {
 173         spin_unlock(&p->alloc_lock);
 174 }
 175 
 176 #endif /* _LINUX_SCHED_TASK_H */