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