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