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 12 struct task_struct; 13 struct rusage; 14 union thread_union; 15 16 /* 17 * This serializes "schedule()" and also protects 18 * the run-queue from deletions/modifications (but 19 * _adding_ to the beginning of the run-queue has 20 * a separate lock). 21 */ 22 extern rwlock_t tasklist_lock; 23 extern spinlock_t mmlist_lock; 24 25 extern union thread_union init_thread_union; 26 extern struct task_struct init_task; 27 28 #ifdef CONFIG_PROVE_RCU 29 extern int lockdep_tasklist_lock_is_held(void); 30 #endif /* #ifdef CONFIG_PROVE_RCU */ 31 32 extern asmlinkage void schedule_tail(struct task_struct *prev); 33 extern void init_idle(struct task_struct *idle, int cpu); 34 35 extern int sched_fork(unsigned long clone_flags, struct task_struct *p); 36 extern void sched_dead(struct task_struct *p); 37 38 void __noreturn do_task_dead(void); 39 40 extern void proc_caches_init(void); 41 42 extern void release_task(struct task_struct * p); 43 44 #ifdef CONFIG_HAVE_COPY_THREAD_TLS 45 extern int copy_thread_tls(unsigned long, unsigned long, unsigned long, 46 struct task_struct *, unsigned long); 47 #else 48 extern int copy_thread(unsigned long, unsigned long, unsigned long, 49 struct task_struct *); 50 51 /* Architectures that haven't opted into copy_thread_tls get the tls argument 52 * via pt_regs, so ignore the tls argument passed via C. */ 53 static inline int copy_thread_tls( 54 unsigned long clone_flags, unsigned long sp, unsigned long arg, 55 struct task_struct *p, unsigned long tls) 56 { 57 return copy_thread(clone_flags, sp, arg, p); 58 } 59 #endif 60 extern void flush_thread(void); 61 62 #ifdef CONFIG_HAVE_EXIT_THREAD 63 extern void exit_thread(struct task_struct *tsk); 64 #else 65 static inline void exit_thread(struct task_struct *tsk) 66 { 67 } 68 #endif 69 extern void do_group_exit(int); 70 71 extern void exit_files(struct task_struct *); 72 extern void exit_itimers(struct signal_struct *); 73 74 extern long _do_fork(unsigned long, unsigned long, unsigned long, int __user *, int __user *, unsigned long); 75 extern long do_fork(unsigned long, unsigned long, unsigned long, int __user *, int __user *); 76 struct task_struct *fork_idle(int); 77 extern pid_t kernel_thread(int (*fn)(void *), void *arg, unsigned long flags); 78 extern long kernel_wait4(pid_t, int __user *, int, struct rusage *); 79 80 extern void free_task(struct task_struct *tsk); 81 82 /* sched_exec is called by processes performing an exec */ 83 #ifdef CONFIG_SMP 84 extern void sched_exec(void); 85 #else 86 #define sched_exec() {} 87 #endif 88 89 #define get_task_struct(tsk) do { atomic_inc(&(tsk)->usage); } while(0) 90 91 extern void __put_task_struct(struct task_struct *t); 92 93 static inline void put_task_struct(struct task_struct *t) 94 { 95 if (atomic_dec_and_test(&t->usage)) 96 __put_task_struct(t); 97 } 98 99 struct task_struct *task_rcu_dereference(struct task_struct **ptask); 100 101 #ifdef CONFIG_ARCH_WANTS_DYNAMIC_TASK_STRUCT 102 extern int arch_task_struct_size __read_mostly; 103 #else 104 # define arch_task_struct_size (sizeof(struct task_struct)) 105 #endif 106 107 #ifndef CONFIG_HAVE_ARCH_THREAD_STRUCT_WHITELIST 108 /* 109 * If an architecture has not declared a thread_struct whitelist we 110 * must assume something there may need to be copied to userspace. 111 */ 112 static inline void arch_thread_struct_whitelist(unsigned long *offset, 113 unsigned long *size) 114 { 115 *offset = 0; 116 /* Handle dynamically sized thread_struct. */ 117 *size = arch_task_struct_size - offsetof(struct task_struct, thread); 118 } 119 #endif 120 121 #ifdef CONFIG_VMAP_STACK 122 static inline struct vm_struct *task_stack_vm_area(const struct task_struct *t) 123 { 124 return t->stack_vm_area; 125 } 126 #else 127 static inline struct vm_struct *task_stack_vm_area(const struct task_struct *t) 128 { 129 return NULL; 130 } 131 #endif 132 133 /* 134 * Protects ->fs, ->files, ->mm, ->group_info, ->comm, keyring 135 * subscriptions and synchronises with wait4(). Also used in procfs. Also 136 * pins the final release of task.io_context. Also protects ->cpuset and 137 * ->cgroup.subsys[]. And ->vfork_done. 138 * 139 * Nests both inside and outside of read_lock(&tasklist_lock). 140 * It must not be nested with write_lock_irq(&tasklist_lock), 141 * neither inside nor outside. 142 */ 143 static inline void task_lock(struct task_struct *p) 144 { 145 spin_lock(&p->alloc_lock); 146 } 147 148 static inline void task_unlock(struct task_struct *p) 149 { 150 spin_unlock(&p->alloc_lock); 151 } 152 153 #endif /* _LINUX_SCHED_TASK_H */ 154