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