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 u32 no_files:1; 32 unsigned long stack; 33 unsigned long stack_size; 34 unsigned long tls; 35 pid_t *set_tid; 36 /* Number of elements in *set_tid */ 37 size_t set_tid_size; 38 int cgroup; 39 int idle; 40 int (*fn)(void *); 41 void *fn_arg; 42 struct cgroup *cgrp; 43 struct css_set *cset; 44 }; 45 46 /* 47 * This serializes "schedule()" and also protects 48 * the run-queue from deletions/modifications (but 49 * _adding_ to the beginning of the run-queue has 50 * a separate lock). 51 */ 52 extern rwlock_t tasklist_lock; 53 extern spinlock_t mmlist_lock; 54 55 extern union thread_union init_thread_union; 56 extern struct task_struct init_task; 57 58 extern int lockdep_tasklist_lock_is_held(void); 59 60 extern asmlinkage void schedule_tail(struct task_struct *prev); 61 extern void init_idle(struct task_struct *idle, int cpu); 62 63 extern int sched_fork(unsigned long clone_flags, struct task_struct *p); 64 extern void sched_cgroup_fork(struct task_struct *p, struct kernel_clone_args *kargs); 65 extern void sched_post_fork(struct task_struct *p); 66 extern void sched_dead(struct task_struct *p); 67 68 void __noreturn do_task_dead(void); 69 void __noreturn make_task_dead(int signr); 70 71 extern void mm_cache_init(void); 72 extern void proc_caches_init(void); 73 74 extern void fork_init(void); 75 76 extern void release_task(struct task_struct * p); 77 78 extern int copy_thread(struct task_struct *, const struct kernel_clone_args *); 79 80 extern void flush_thread(void); 81 82 #ifdef CONFIG_HAVE_EXIT_THREAD 83 extern void exit_thread(struct task_struct *tsk); 84 #else 85 static inline void exit_thread(struct task_struct *tsk) 86 { 87 } 88 #endif 89 extern __noreturn void do_group_exit(int); 90 91 extern void exit_files(struct task_struct *); 92 extern void exit_itimers(struct task_struct *); 93 94 extern pid_t kernel_clone(struct kernel_clone_args *kargs); 95 struct task_struct *copy_process(struct pid *pid, int trace, int node, 96 struct kernel_clone_args *args); 97 struct task_struct *create_io_thread(int (*fn)(void *), void *arg, int node); 98 struct task_struct *fork_idle(int); 99 extern pid_t kernel_thread(int (*fn)(void *), void *arg, const char *name, 100 unsigned long flags); 101 extern pid_t user_mode_thread(int (*fn)(void *), void *arg, unsigned long flags); 102 extern long kernel_wait4(pid_t, int __user *, int, struct rusage *); 103 int kernel_wait(pid_t pid, int *stat); 104 105 extern void free_task(struct task_struct *tsk); 106 107 /* sched_exec is called by processes performing an exec */ 108 #ifdef CONFIG_SMP 109 extern void sched_exec(void); 110 #else 111 #define sched_exec() {} 112 #endif 113 114 static inline struct task_struct *get_task_struct(struct task_struct *t) 115 { 116 refcount_inc(&t->usage); 117 return t; 118 } 119 120 extern void __put_task_struct(struct task_struct *t); 121 122 static inline void put_task_struct(struct task_struct *t) 123 { 124 if (refcount_dec_and_test(&t->usage)) 125 __put_task_struct(t); 126 } 127 128 DEFINE_FREE(put_task, struct task_struct *, if (_T) put_task_struct(_T)) 129 130 static inline void put_task_struct_many(struct task_struct *t, int nr) 131 { 132 if (refcount_sub_and_test(nr, &t->usage)) 133 __put_task_struct(t); 134 } 135 136 void put_task_struct_rcu_user(struct task_struct *task); 137 138 /* Free all architecture-specific resources held by a thread. */ 139 void release_thread(struct task_struct *dead_task); 140 141 #ifdef CONFIG_ARCH_WANTS_DYNAMIC_TASK_STRUCT 142 extern int arch_task_struct_size __read_mostly; 143 #else 144 # define arch_task_struct_size (sizeof(struct task_struct)) 145 #endif 146 147 #ifndef CONFIG_HAVE_ARCH_THREAD_STRUCT_WHITELIST 148 /* 149 * If an architecture has not declared a thread_struct whitelist we 150 * must assume something there may need to be copied to userspace. 151 */ 152 static inline void arch_thread_struct_whitelist(unsigned long *offset, 153 unsigned long *size) 154 { 155 *offset = 0; 156 /* Handle dynamically sized thread_struct. */ 157 *size = arch_task_struct_size - offsetof(struct task_struct, thread); 158 } 159 #endif 160 161 #ifdef CONFIG_VMAP_STACK 162 static inline struct vm_struct *task_stack_vm_area(const struct task_struct *t) 163 { 164 return t->stack_vm_area; 165 } 166 #else 167 static inline struct vm_struct *task_stack_vm_area(const struct task_struct *t) 168 { 169 return NULL; 170 } 171 #endif 172 173 /* 174 * Protects ->fs, ->files, ->mm, ->group_info, ->comm, keyring 175 * subscriptions and synchronises with wait4(). Also used in procfs. Also 176 * pins the final release of task.io_context. Also protects ->cpuset and 177 * ->cgroup.subsys[]. And ->vfork_done. And ->sysvshm.shm_clist. 178 * 179 * Nests both inside and outside of read_lock(&tasklist_lock). 180 * It must not be nested with write_lock_irq(&tasklist_lock), 181 * neither inside nor outside. 182 */ 183 static inline void task_lock(struct task_struct *p) 184 { 185 spin_lock(&p->alloc_lock); 186 } 187 188 static inline void task_unlock(struct task_struct *p) 189 { 190 spin_unlock(&p->alloc_lock); 191 } 192 193 #endif /* _LINUX_SCHED_TASK_H */ 194