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 int idle; 37 int (*fn)(void *); 38 void *fn_arg; 39 struct cgroup *cgrp; 40 struct css_set *cset; 41 }; 42 43 /* 44 * This serializes "schedule()" and also protects 45 * the run-queue from deletions/modifications (but 46 * _adding_ to the beginning of the run-queue has 47 * a separate lock). 48 */ 49 extern rwlock_t tasklist_lock; 50 extern spinlock_t mmlist_lock; 51 52 extern union thread_union init_thread_union; 53 extern struct task_struct init_task; 54 55 extern int lockdep_tasklist_lock_is_held(void); 56 57 extern asmlinkage void schedule_tail(struct task_struct *prev); 58 extern void init_idle(struct task_struct *idle, int cpu); 59 60 extern int sched_fork(unsigned long clone_flags, struct task_struct *p); 61 extern void sched_cgroup_fork(struct task_struct *p, struct kernel_clone_args *kargs); 62 extern void sched_post_fork(struct task_struct *p); 63 extern void sched_dead(struct task_struct *p); 64 65 void __noreturn do_task_dead(void); 66 void __noreturn make_task_dead(int signr); 67 68 extern void mm_cache_init(void); 69 extern void proc_caches_init(void); 70 71 extern void fork_init(void); 72 73 extern void release_task(struct task_struct * p); 74 75 extern int copy_thread(struct task_struct *, const struct kernel_clone_args *); 76 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 __noreturn void do_group_exit(int); 87 88 extern void exit_files(struct task_struct *); 89 extern void exit_itimers(struct task_struct *); 90 91 extern pid_t kernel_clone(struct kernel_clone_args *kargs); 92 struct task_struct *create_io_thread(int (*fn)(void *), void *arg, int node); 93 struct task_struct *fork_idle(int); 94 extern pid_t kernel_thread(int (*fn)(void *), void *arg, unsigned long flags); 95 extern pid_t user_mode_thread(int (*fn)(void *), void *arg, unsigned long flags); 96 extern long kernel_wait4(pid_t, int __user *, int, struct rusage *); 97 int kernel_wait(pid_t pid, int *stat); 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 static inline void put_task_struct_many(struct task_struct *t, int nr) 123 { 124 if (refcount_sub_and_test(nr, &t->usage)) 125 __put_task_struct(t); 126 } 127 128 void put_task_struct_rcu_user(struct task_struct *task); 129 130 /* Free all architecture-specific resources held by a thread. */ 131 void release_thread(struct task_struct *dead_task); 132 133 #ifdef CONFIG_ARCH_WANTS_DYNAMIC_TASK_STRUCT 134 extern int arch_task_struct_size __read_mostly; 135 #else 136 # define arch_task_struct_size (sizeof(struct task_struct)) 137 #endif 138 139 #ifndef CONFIG_HAVE_ARCH_THREAD_STRUCT_WHITELIST 140 /* 141 * If an architecture has not declared a thread_struct whitelist we 142 * must assume something there may need to be copied to userspace. 143 */ 144 static inline void arch_thread_struct_whitelist(unsigned long *offset, 145 unsigned long *size) 146 { 147 *offset = 0; 148 /* Handle dynamically sized thread_struct. */ 149 *size = arch_task_struct_size - offsetof(struct task_struct, thread); 150 } 151 #endif 152 153 #ifdef CONFIG_VMAP_STACK 154 static inline struct vm_struct *task_stack_vm_area(const struct task_struct *t) 155 { 156 return t->stack_vm_area; 157 } 158 #else 159 static inline struct vm_struct *task_stack_vm_area(const struct task_struct *t) 160 { 161 return NULL; 162 } 163 #endif 164 165 /* 166 * Protects ->fs, ->files, ->mm, ->group_info, ->comm, keyring 167 * subscriptions and synchronises with wait4(). Also used in procfs. Also 168 * pins the final release of task.io_context. Also protects ->cpuset and 169 * ->cgroup.subsys[]. And ->vfork_done. And ->sysvshm.shm_clist. 170 * 171 * Nests both inside and outside of read_lock(&tasklist_lock). 172 * It must not be nested with write_lock_irq(&tasklist_lock), 173 * neither inside nor outside. 174 */ 175 static inline void task_lock(struct task_struct *p) 176 { 177 spin_lock(&p->alloc_lock); 178 } 179 180 static inline void task_unlock(struct task_struct *p) 181 { 182 spin_unlock(&p->alloc_lock); 183 } 184 185 #endif /* _LINUX_SCHED_TASK_H */ 186