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 #ifdef CONFIG_PROVE_RCU 51 extern int lockdep_tasklist_lock_is_held(void); 52 #endif /* #ifdef CONFIG_PROVE_RCU */ 53 54 extern asmlinkage void schedule_tail(struct task_struct *prev); 55 extern void init_idle(struct task_struct *idle, int cpu); 56 57 extern int sched_fork(unsigned long clone_flags, struct task_struct *p); 58 extern void sched_post_fork(struct task_struct *p); 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 long _do_fork(struct kernel_clone_args *kargs); 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 92 extern void free_task(struct task_struct *tsk); 93 94 /* sched_exec is called by processes performing an exec */ 95 #ifdef CONFIG_SMP 96 extern void sched_exec(void); 97 #else 98 #define sched_exec() {} 99 #endif 100 101 static inline struct task_struct *get_task_struct(struct task_struct *t) 102 { 103 refcount_inc(&t->usage); 104 return t; 105 } 106 107 extern void __put_task_struct(struct task_struct *t); 108 109 static inline void put_task_struct(struct task_struct *t) 110 { 111 if (refcount_dec_and_test(&t->usage)) 112 __put_task_struct(t); 113 } 114 115 static inline void put_task_struct_many(struct task_struct *t, int nr) 116 { 117 if (refcount_sub_and_test(nr, &t->usage)) 118 __put_task_struct(t); 119 } 120 121 void put_task_struct_rcu_user(struct task_struct *task); 122 123 #ifdef CONFIG_ARCH_WANTS_DYNAMIC_TASK_STRUCT 124 extern int arch_task_struct_size __read_mostly; 125 #else 126 # define arch_task_struct_size (sizeof(struct task_struct)) 127 #endif 128 129 #ifndef CONFIG_HAVE_ARCH_THREAD_STRUCT_WHITELIST 130 /* 131 * If an architecture has not declared a thread_struct whitelist we 132 * must assume something there may need to be copied to userspace. 133 */ 134 static inline void arch_thread_struct_whitelist(unsigned long *offset, 135 unsigned long *size) 136 { 137 *offset = 0; 138 /* Handle dynamically sized thread_struct. */ 139 *size = arch_task_struct_size - offsetof(struct task_struct, thread); 140 } 141 #endif 142 143 #ifdef CONFIG_VMAP_STACK 144 static inline struct vm_struct *task_stack_vm_area(const struct task_struct *t) 145 { 146 return t->stack_vm_area; 147 } 148 #else 149 static inline struct vm_struct *task_stack_vm_area(const struct task_struct *t) 150 { 151 return NULL; 152 } 153 #endif 154 155 /* 156 * Protects ->fs, ->files, ->mm, ->group_info, ->comm, keyring 157 * subscriptions and synchronises with wait4(). Also used in procfs. Also 158 * pins the final release of task.io_context. Also protects ->cpuset and 159 * ->cgroup.subsys[]. And ->vfork_done. 160 * 161 * Nests both inside and outside of read_lock(&tasklist_lock). 162 * It must not be nested with write_lock_irq(&tasklist_lock), 163 * neither inside nor outside. 164 */ 165 static inline void task_lock(struct task_struct *p) 166 { 167 spin_lock(&p->alloc_lock); 168 } 169 170 static inline void task_unlock(struct task_struct *p) 171 { 172 spin_unlock(&p->alloc_lock); 173 } 174 175 #endif /* _LINUX_SCHED_TASK_H */ 176