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