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