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_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 #ifdef CONFIG_HAVE_COPY_THREAD_TLS 69 extern int copy_thread_tls(unsigned long, unsigned long, unsigned long, 70 struct task_struct *, unsigned long); 71 #else 72 extern int copy_thread(unsigned long, unsigned long, unsigned long, 73 struct task_struct *); 74 75 /* Architectures that haven't opted into copy_thread_tls get the tls argument 76 * via pt_regs, so ignore the tls argument passed via C. */ 77 static inline int copy_thread_tls( 78 unsigned long clone_flags, unsigned long sp, unsigned long arg, 79 struct task_struct *p, unsigned long tls) 80 { 81 return copy_thread(clone_flags, sp, arg, p); 82 } 83 #endif 84 extern void flush_thread(void); 85 86 #ifdef CONFIG_HAVE_EXIT_THREAD 87 extern void exit_thread(struct task_struct *tsk); 88 #else 89 static inline void exit_thread(struct task_struct *tsk) 90 { 91 } 92 #endif 93 extern void do_group_exit(int); 94 95 extern void exit_files(struct task_struct *); 96 extern void exit_itimers(struct signal_struct *); 97 98 extern long _do_fork(struct kernel_clone_args *kargs); 99 extern bool legacy_clone_args_valid(const struct kernel_clone_args *kargs); 100 extern long do_fork(unsigned long, unsigned long, unsigned long, int __user *, int __user *); 101 struct task_struct *fork_idle(int); 102 struct mm_struct *copy_init_mm(void); 103 extern pid_t kernel_thread(int (*fn)(void *), void *arg, unsigned long flags); 104 extern long kernel_wait4(pid_t, int __user *, int, struct rusage *); 105 106 extern void free_task(struct task_struct *tsk); 107 108 /* sched_exec is called by processes performing an exec */ 109 #ifdef CONFIG_SMP 110 extern void sched_exec(void); 111 #else 112 #define sched_exec() {} 113 #endif 114 115 static inline struct task_struct *get_task_struct(struct task_struct *t) 116 { 117 refcount_inc(&t->usage); 118 return t; 119 } 120 121 extern void __put_task_struct(struct task_struct *t); 122 123 static inline void put_task_struct(struct task_struct *t) 124 { 125 if (refcount_dec_and_test(&t->usage)) 126 __put_task_struct(t); 127 } 128 129 void put_task_struct_rcu_user(struct task_struct *task); 130 131 #ifdef CONFIG_ARCH_WANTS_DYNAMIC_TASK_STRUCT 132 extern int arch_task_struct_size __read_mostly; 133 #else 134 # define arch_task_struct_size (sizeof(struct task_struct)) 135 #endif 136 137 #ifndef CONFIG_HAVE_ARCH_THREAD_STRUCT_WHITELIST 138 /* 139 * If an architecture has not declared a thread_struct whitelist we 140 * must assume something there may need to be copied to userspace. 141 */ 142 static inline void arch_thread_struct_whitelist(unsigned long *offset, 143 unsigned long *size) 144 { 145 *offset = 0; 146 /* Handle dynamically sized thread_struct. */ 147 *size = arch_task_struct_size - offsetof(struct task_struct, thread); 148 } 149 #endif 150 151 #ifdef CONFIG_VMAP_STACK 152 static inline struct vm_struct *task_stack_vm_area(const struct task_struct *t) 153 { 154 return t->stack_vm_area; 155 } 156 #else 157 static inline struct vm_struct *task_stack_vm_area(const struct task_struct *t) 158 { 159 return NULL; 160 } 161 #endif 162 163 /* 164 * Protects ->fs, ->files, ->mm, ->group_info, ->comm, keyring 165 * subscriptions and synchronises with wait4(). Also used in procfs. Also 166 * pins the final release of task.io_context. Also protects ->cpuset and 167 * ->cgroup.subsys[]. And ->vfork_done. 168 * 169 * Nests both inside and outside of read_lock(&tasklist_lock). 170 * It must not be nested with write_lock_irq(&tasklist_lock), 171 * neither inside nor outside. 172 */ 173 static inline void task_lock(struct task_struct *p) 174 { 175 spin_lock(&p->alloc_lock); 176 } 177 178 static inline void task_unlock(struct task_struct *p) 179 { 180 spin_unlock(&p->alloc_lock); 181 } 182 183 #endif /* _LINUX_SCHED_TASK_H */ 184