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