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 const char *name; 27 int exit_signal; 28 u32 kthread:1; 29 u32 io_thread:1; 30 u32 user_worker:1; 31 unsigned long stack; 32 unsigned long stack_size; 33 unsigned long tls; 34 pid_t *set_tid; 35 /* Number of elements in *set_tid */ 36 size_t set_tid_size; 37 int cgroup; 38 int idle; 39 int (*fn)(void *); 40 void *fn_arg; 41 struct cgroup *cgrp; 42 struct css_set *cset; 43 }; 44 45 /* 46 * This serializes "schedule()" and also protects 47 * the run-queue from deletions/modifications (but 48 * _adding_ to the beginning of the run-queue has 49 * a separate lock). 50 */ 51 extern rwlock_t tasklist_lock; 52 extern spinlock_t mmlist_lock; 53 54 extern union thread_union init_thread_union; 55 extern struct task_struct init_task; 56 57 extern int lockdep_tasklist_lock_is_held(void); 58 59 extern asmlinkage void schedule_tail(struct task_struct *prev); 60 extern void init_idle(struct task_struct *idle, int cpu); 61 62 extern int sched_fork(unsigned long clone_flags, struct task_struct *p); 63 extern void sched_cgroup_fork(struct task_struct *p, struct kernel_clone_args *kargs); 64 extern void sched_post_fork(struct task_struct *p); 65 extern void sched_dead(struct task_struct *p); 66 67 void __noreturn do_task_dead(void); 68 void __noreturn make_task_dead(int signr); 69 70 extern void mm_cache_init(void); 71 extern void proc_caches_init(void); 72 73 extern void fork_init(void); 74 75 extern void release_task(struct task_struct * p); 76 77 extern int copy_thread(struct task_struct *, const struct kernel_clone_args *); 78 79 extern void flush_thread(void); 80 81 #ifdef CONFIG_HAVE_EXIT_THREAD 82 extern void exit_thread(struct task_struct *tsk); 83 #else 84 static inline void exit_thread(struct task_struct *tsk) 85 { 86 } 87 #endif 88 extern __noreturn void do_group_exit(int); 89 90 extern void exit_files(struct task_struct *); 91 extern void exit_itimers(struct task_struct *); 92 93 extern pid_t kernel_clone(struct kernel_clone_args *kargs); 94 struct task_struct *create_io_thread(int (*fn)(void *), void *arg, int node); 95 struct task_struct *fork_idle(int); 96 extern pid_t kernel_thread(int (*fn)(void *), void *arg, const char *name, 97 unsigned long flags); 98 extern pid_t user_mode_thread(int (*fn)(void *), void *arg, unsigned long flags); 99 extern long kernel_wait4(pid_t, int __user *, int, struct rusage *); 100 int kernel_wait(pid_t pid, int *stat); 101 102 extern void free_task(struct task_struct *tsk); 103 104 /* sched_exec is called by processes performing an exec */ 105 #ifdef CONFIG_SMP 106 extern void sched_exec(void); 107 #else 108 #define sched_exec() {} 109 #endif 110 111 static inline struct task_struct *get_task_struct(struct task_struct *t) 112 { 113 refcount_inc(&t->usage); 114 return t; 115 } 116 117 extern void __put_task_struct(struct task_struct *t); 118 119 static inline void put_task_struct(struct task_struct *t) 120 { 121 if (refcount_dec_and_test(&t->usage)) 122 __put_task_struct(t); 123 } 124 125 static inline void put_task_struct_many(struct task_struct *t, int nr) 126 { 127 if (refcount_sub_and_test(nr, &t->usage)) 128 __put_task_struct(t); 129 } 130 131 void put_task_struct_rcu_user(struct task_struct *task); 132 133 /* Free all architecture-specific resources held by a thread. */ 134 void release_thread(struct task_struct *dead_task); 135 136 #ifdef CONFIG_ARCH_WANTS_DYNAMIC_TASK_STRUCT 137 extern int arch_task_struct_size __read_mostly; 138 #else 139 # define arch_task_struct_size (sizeof(struct task_struct)) 140 #endif 141 142 #ifndef CONFIG_HAVE_ARCH_THREAD_STRUCT_WHITELIST 143 /* 144 * If an architecture has not declared a thread_struct whitelist we 145 * must assume something there may need to be copied to userspace. 146 */ 147 static inline void arch_thread_struct_whitelist(unsigned long *offset, 148 unsigned long *size) 149 { 150 *offset = 0; 151 /* Handle dynamically sized thread_struct. */ 152 *size = arch_task_struct_size - offsetof(struct task_struct, thread); 153 } 154 #endif 155 156 #ifdef CONFIG_VMAP_STACK 157 static inline struct vm_struct *task_stack_vm_area(const struct task_struct *t) 158 { 159 return t->stack_vm_area; 160 } 161 #else 162 static inline struct vm_struct *task_stack_vm_area(const struct task_struct *t) 163 { 164 return NULL; 165 } 166 #endif 167 168 /* 169 * Protects ->fs, ->files, ->mm, ->group_info, ->comm, keyring 170 * subscriptions and synchronises with wait4(). Also used in procfs. Also 171 * pins the final release of task.io_context. Also protects ->cpuset and 172 * ->cgroup.subsys[]. And ->vfork_done. And ->sysvshm.shm_clist. 173 * 174 * Nests both inside and outside of read_lock(&tasklist_lock). 175 * It must not be nested with write_lock_irq(&tasklist_lock), 176 * neither inside nor outside. 177 */ 178 static inline void task_lock(struct task_struct *p) 179 { 180 spin_lock(&p->alloc_lock); 181 } 182 183 static inline void task_unlock(struct task_struct *p) 184 { 185 spin_unlock(&p->alloc_lock); 186 } 187 188 #endif /* _LINUX_SCHED_TASK_H */ 189