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