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 17 /* All the bits taken by the old clone syscall. */ 18 #define CLONE_LEGACY_FLAGS 0xffffffffULL 19 20 struct kernel_clone_args { 21 u64 flags; 22 int __user *pidfd; 23 int __user *child_tid; 24 int __user *parent_tid; 25 int exit_signal; 26 unsigned long stack; 27 unsigned long stack_size; 28 unsigned long tls; 29 pid_t *set_tid; 30 /* Number of elements in *set_tid */ 31 size_t set_tid_size; 32 }; 33 34 /* 35 * This serializes "schedule()" and also protects 36 * the run-queue from deletions/modifications (but 37 * _adding_ to the beginning of the run-queue has 38 * a separate lock). 39 */ 40 extern rwlock_t tasklist_lock; 41 extern spinlock_t mmlist_lock; 42 43 extern union thread_union init_thread_union; 44 extern struct task_struct init_task; 45 46 #ifdef CONFIG_PROVE_RCU 47 extern int lockdep_tasklist_lock_is_held(void); 48 #endif /* #ifdef CONFIG_PROVE_RCU */ 49 50 extern asmlinkage void schedule_tail(struct task_struct *prev); 51 extern void init_idle(struct task_struct *idle, int cpu); 52 53 extern int sched_fork(unsigned long clone_flags, struct task_struct *p); 54 extern void sched_dead(struct task_struct *p); 55 56 void __noreturn do_task_dead(void); 57 58 extern void proc_caches_init(void); 59 60 extern void fork_init(void); 61 62 extern void release_task(struct task_struct * p); 63 64 #ifdef CONFIG_HAVE_COPY_THREAD_TLS 65 extern int copy_thread_tls(unsigned long, unsigned long, unsigned long, 66 struct task_struct *, unsigned long); 67 #else 68 extern int copy_thread(unsigned long, unsigned long, unsigned long, 69 struct task_struct *); 70 71 /* Architectures that haven't opted into copy_thread_tls get the tls argument 72 * via pt_regs, so ignore the tls argument passed via C. */ 73 static inline int copy_thread_tls( 74 unsigned long clone_flags, unsigned long sp, unsigned long arg, 75 struct task_struct *p, unsigned long tls) 76 { 77 return copy_thread(clone_flags, sp, arg, p); 78 } 79 #endif 80 extern void flush_thread(void); 81 82 #ifdef CONFIG_HAVE_EXIT_THREAD 83 extern void exit_thread(struct task_struct *tsk); 84 #else 85 static inline void exit_thread(struct task_struct *tsk) 86 { 87 } 88 #endif 89 extern void do_group_exit(int); 90 91 extern void exit_files(struct task_struct *); 92 extern void exit_itimers(struct signal_struct *); 93 94 extern long _do_fork(struct kernel_clone_args *kargs); 95 extern bool legacy_clone_args_valid(const struct kernel_clone_args *kargs); 96 extern long do_fork(unsigned long, unsigned long, unsigned long, int __user *, int __user *); 97 struct task_struct *fork_idle(int); 98 struct mm_struct *copy_init_mm(void); 99 extern pid_t kernel_thread(int (*fn)(void *), void *arg, unsigned long flags); 100 extern long kernel_wait4(pid_t, int __user *, int, struct rusage *); 101 102 extern void free_task(struct task_struct *tsk); 103 104 /* sched_exec is called by processes performing an exec */ 105 #ifdef CONFIG_SMP 106 extern void sched_exec(void); 107 #else 108 #define sched_exec() {} 109 #endif 110 111 static inline struct task_struct *get_task_struct(struct task_struct *t) 112 { 113 refcount_inc(&t->usage); 114 return t; 115 } 116 117 extern void __put_task_struct(struct task_struct *t); 118 119 static inline void put_task_struct(struct task_struct *t) 120 { 121 if (refcount_dec_and_test(&t->usage)) 122 __put_task_struct(t); 123 } 124 125 void put_task_struct_rcu_user(struct task_struct *task); 126 127 #ifdef CONFIG_ARCH_WANTS_DYNAMIC_TASK_STRUCT 128 extern int arch_task_struct_size __read_mostly; 129 #else 130 # define arch_task_struct_size (sizeof(struct task_struct)) 131 #endif 132 133 #ifndef CONFIG_HAVE_ARCH_THREAD_STRUCT_WHITELIST 134 /* 135 * If an architecture has not declared a thread_struct whitelist we 136 * must assume something there may need to be copied to userspace. 137 */ 138 static inline void arch_thread_struct_whitelist(unsigned long *offset, 139 unsigned long *size) 140 { 141 *offset = 0; 142 /* Handle dynamically sized thread_struct. */ 143 *size = arch_task_struct_size - offsetof(struct task_struct, thread); 144 } 145 #endif 146 147 #ifdef CONFIG_VMAP_STACK 148 static inline struct vm_struct *task_stack_vm_area(const struct task_struct *t) 149 { 150 return t->stack_vm_area; 151 } 152 #else 153 static inline struct vm_struct *task_stack_vm_area(const struct task_struct *t) 154 { 155 return NULL; 156 } 157 #endif 158 159 /* 160 * Protects ->fs, ->files, ->mm, ->group_info, ->comm, keyring 161 * subscriptions and synchronises with wait4(). Also used in procfs. Also 162 * pins the final release of task.io_context. Also protects ->cpuset and 163 * ->cgroup.subsys[]. And ->vfork_done. 164 * 165 * Nests both inside and outside of read_lock(&tasklist_lock). 166 * It must not be nested with write_lock_irq(&tasklist_lock), 167 * neither inside nor outside. 168 */ 169 static inline void task_lock(struct task_struct *p) 170 { 171 spin_lock(&p->alloc_lock); 172 } 173 174 static inline void task_unlock(struct task_struct *p) 175 { 176 spin_unlock(&p->alloc_lock); 177 } 178 179 #endif /* _LINUX_SCHED_TASK_H */ 180