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 int kthread; 36 struct cgroup *cgrp; 37 struct css_set *cset; 38 }; 39 40 /* 41 * This serializes "schedule()" and also protects 42 * the run-queue from deletions/modifications (but 43 * _adding_ to the beginning of the run-queue has 44 * a separate lock). 45 */ 46 extern rwlock_t tasklist_lock; 47 extern spinlock_t mmlist_lock; 48 49 extern union thread_union init_thread_union; 50 extern struct task_struct init_task; 51 52 extern int lockdep_tasklist_lock_is_held(void); 53 54 extern asmlinkage void schedule_tail(struct task_struct *prev); 55 extern void init_idle(struct task_struct *idle, int cpu); 56 57 extern int sched_fork(unsigned long clone_flags, struct task_struct *p); 58 extern void sched_cgroup_fork(struct task_struct *p, struct kernel_clone_args *kargs); 59 extern void sched_post_fork(struct task_struct *p); 60 extern void sched_dead(struct task_struct *p); 61 62 void __noreturn do_task_dead(void); 63 void __noreturn make_task_dead(int signr); 64 65 extern void proc_caches_init(void); 66 67 extern void fork_init(void); 68 69 extern void release_task(struct task_struct * p); 70 71 extern int copy_thread(struct task_struct *, const struct kernel_clone_args *); 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 __noreturn 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 pid_t user_mode_thread(int (*fn)(void *), void *arg, unsigned long flags); 93 extern long kernel_wait4(pid_t, int __user *, int, struct rusage *); 94 int kernel_wait(pid_t pid, int *stat); 95 96 extern void free_task(struct task_struct *tsk); 97 98 /* sched_exec is called by processes performing an exec */ 99 #ifdef CONFIG_SMP 100 extern void sched_exec(void); 101 #else 102 #define sched_exec() {} 103 #endif 104 105 static inline struct task_struct *get_task_struct(struct task_struct *t) 106 { 107 refcount_inc(&t->usage); 108 return t; 109 } 110 111 extern void __put_task_struct(struct task_struct *t); 112 113 static inline void put_task_struct(struct task_struct *t) 114 { 115 if (refcount_dec_and_test(&t->usage)) 116 __put_task_struct(t); 117 } 118 119 static inline void put_task_struct_many(struct task_struct *t, int nr) 120 { 121 if (refcount_sub_and_test(nr, &t->usage)) 122 __put_task_struct(t); 123 } 124 125 void put_task_struct_rcu_user(struct task_struct *task); 126 127 #ifdef CONFIG_ARCH_WANTS_DYNAMIC_TASK_STRUCT 128 extern int arch_task_struct_size __read_mostly; 129 #else 130 # define arch_task_struct_size (sizeof(struct task_struct)) 131 #endif 132 133 #ifndef CONFIG_HAVE_ARCH_THREAD_STRUCT_WHITELIST 134 /* 135 * If an architecture has not declared a thread_struct whitelist we 136 * must assume something there may need to be copied to userspace. 137 */ 138 static inline void arch_thread_struct_whitelist(unsigned long *offset, 139 unsigned long *size) 140 { 141 *offset = 0; 142 /* Handle dynamically sized thread_struct. */ 143 *size = arch_task_struct_size - offsetof(struct task_struct, thread); 144 } 145 #endif 146 147 #ifdef CONFIG_VMAP_STACK 148 static inline struct vm_struct *task_stack_vm_area(const struct task_struct *t) 149 { 150 return t->stack_vm_area; 151 } 152 #else 153 static inline struct vm_struct *task_stack_vm_area(const struct task_struct *t) 154 { 155 return NULL; 156 } 157 #endif 158 159 /* 160 * Protects ->fs, ->files, ->mm, ->group_info, ->comm, keyring 161 * subscriptions and synchronises with wait4(). Also used in procfs. Also 162 * pins the final release of task.io_context. Also protects ->cpuset and 163 * ->cgroup.subsys[]. And ->vfork_done. And ->sysvshm.shm_clist. 164 * 165 * Nests both inside and outside of read_lock(&tasklist_lock). 166 * It must not be nested with write_lock_irq(&tasklist_lock), 167 * neither inside nor outside. 168 */ 169 static inline void task_lock(struct task_struct *p) 170 { 171 spin_lock(&p->alloc_lock); 172 } 173 174 static inline void task_unlock(struct task_struct *p) 175 { 176 spin_unlock(&p->alloc_lock); 177 } 178 179 #endif /* _LINUX_SCHED_TASK_H */ 180