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