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Diffstat (limited to 'include/linux/sched/task.h')
| -rw-r--r-- | include/linux/sched/task.h | 211 |
1 files changed, 211 insertions, 0 deletions
diff --git a/include/linux/sched/task.h b/include/linux/sched/task.h new file mode 100644 index 000000000..7291fb639 --- /dev/null +++ b/include/linux/sched/task.h @@ -0,0 +1,211 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _LINUX_SCHED_TASK_H +#define _LINUX_SCHED_TASK_H + +/* + * Interface between the scheduler and various task lifetime (fork()/exit()) + * functionality: + */ + +#include <linux/sched.h> +#include <linux/uaccess.h> + +struct task_struct; +struct rusage; +union thread_union; +struct css_set; + +/* All the bits taken by the old clone syscall. */ +#define CLONE_LEGACY_FLAGS 0xffffffffULL + +struct kernel_clone_args { + u64 flags; + int __user *pidfd; + int __user *child_tid; + int __user *parent_tid; + int exit_signal; + unsigned long stack; + unsigned long stack_size; + unsigned long tls; + pid_t *set_tid; + /* Number of elements in *set_tid */ + size_t set_tid_size; + int cgroup; + int io_thread; + int kthread; + int idle; + int (*fn)(void *); + void *fn_arg; + struct cgroup *cgrp; + struct css_set *cset; +}; + +/* + * This serializes "schedule()" and also protects + * the run-queue from deletions/modifications (but + * _adding_ to the beginning of the run-queue has + * a separate lock). + */ +extern rwlock_t tasklist_lock; +extern spinlock_t mmlist_lock; + +extern union thread_union init_thread_union; +extern struct task_struct init_task; + +extern int lockdep_tasklist_lock_is_held(void); + +extern asmlinkage void schedule_tail(struct task_struct *prev); +extern void init_idle(struct task_struct *idle, int cpu); + +extern int sched_fork(unsigned long clone_flags, struct task_struct *p); +extern void sched_cgroup_fork(struct task_struct *p, struct kernel_clone_args *kargs); +extern void sched_post_fork(struct task_struct *p); +extern void sched_dead(struct task_struct *p); + +void __noreturn do_task_dead(void); +void __noreturn make_task_dead(int signr); + +extern void mm_cache_init(void); +extern void proc_caches_init(void); + +extern void fork_init(void); + +extern void release_task(struct task_struct * p); + +extern int copy_thread(struct task_struct *, const struct kernel_clone_args *); + +extern void flush_thread(void); + +#ifdef CONFIG_HAVE_EXIT_THREAD +extern void exit_thread(struct task_struct *tsk); +#else +static inline void exit_thread(struct task_struct *tsk) +{ +} +#endif +extern __noreturn void do_group_exit(int); + +extern void exit_files(struct task_struct *); +extern void exit_itimers(struct task_struct *); + +extern pid_t kernel_clone(struct kernel_clone_args *kargs); +struct task_struct *create_io_thread(int (*fn)(void *), void *arg, int node); +struct task_struct *fork_idle(int); +extern pid_t kernel_thread(int (*fn)(void *), void *arg, unsigned long flags); +extern pid_t user_mode_thread(int (*fn)(void *), void *arg, unsigned long flags); +extern long kernel_wait4(pid_t, int __user *, int, struct rusage *); +int kernel_wait(pid_t pid, int *stat); + +extern void free_task(struct task_struct *tsk); + +/* sched_exec is called by processes performing an exec */ +#ifdef CONFIG_SMP +extern void sched_exec(void); +#else +#define sched_exec() {} +#endif + +static inline struct task_struct *get_task_struct(struct task_struct *t) +{ + refcount_inc(&t->usage); + return t; +} + +extern void __put_task_struct(struct task_struct *t); +extern void __put_task_struct_rcu_cb(struct rcu_head *rhp); + +static inline void put_task_struct(struct task_struct *t) +{ + if (!refcount_dec_and_test(&t->usage)) + return; + + /* + * under PREEMPT_RT, we can't call put_task_struct + * in atomic context because it will indirectly + * acquire sleeping locks. + * + * call_rcu() will schedule delayed_put_task_struct_rcu() + * to be called in process context. + * + * __put_task_struct() is called when + * refcount_dec_and_test(&t->usage) succeeds. + * + * This means that it can't "conflict" with + * put_task_struct_rcu_user() which abuses ->rcu the same + * way; rcu_users has a reference so task->usage can't be + * zero after rcu_users 1 -> 0 transition. + * + * delayed_free_task() also uses ->rcu, but it is only called + * when it fails to fork a process. Therefore, there is no + * way it can conflict with put_task_struct(). + */ + if (IS_ENABLED(CONFIG_PREEMPT_RT) && !preemptible()) + call_rcu(&t->rcu, __put_task_struct_rcu_cb); + else + __put_task_struct(t); +} + +static inline void put_task_struct_many(struct task_struct *t, int nr) +{ + if (refcount_sub_and_test(nr, &t->usage)) + __put_task_struct(t); +} + +void put_task_struct_rcu_user(struct task_struct *task); + +/* Free all architecture-specific resources held by a thread. */ +void release_thread(struct task_struct *dead_task); + +#ifdef CONFIG_ARCH_WANTS_DYNAMIC_TASK_STRUCT +extern int arch_task_struct_size __read_mostly; +#else +# define arch_task_struct_size (sizeof(struct task_struct)) +#endif + +#ifndef CONFIG_HAVE_ARCH_THREAD_STRUCT_WHITELIST +/* + * If an architecture has not declared a thread_struct whitelist we + * must assume something there may need to be copied to userspace. + */ +static inline void arch_thread_struct_whitelist(unsigned long *offset, + unsigned long *size) +{ + *offset = 0; + /* Handle dynamically sized thread_struct. */ + *size = arch_task_struct_size - offsetof(struct task_struct, thread); +} +#endif + +#ifdef CONFIG_VMAP_STACK +static inline struct vm_struct *task_stack_vm_area(const struct task_struct *t) +{ + return t->stack_vm_area; +} +#else +static inline struct vm_struct *task_stack_vm_area(const struct task_struct *t) +{ + return NULL; +} +#endif + +/* + * Protects ->fs, ->files, ->mm, ->group_info, ->comm, keyring + * subscriptions and synchronises with wait4(). Also used in procfs. Also + * pins the final release of task.io_context. Also protects ->cpuset and + * ->cgroup.subsys[]. And ->vfork_done. And ->sysvshm.shm_clist. + * + * Nests both inside and outside of read_lock(&tasklist_lock). + * It must not be nested with write_lock_irq(&tasklist_lock), + * neither inside nor outside. + */ +static inline void task_lock(struct task_struct *p) +{ + spin_lock(&p->alloc_lock); +} + +static inline void task_unlock(struct task_struct *p) +{ + spin_unlock(&p->alloc_lock); +} + +#endif /* _LINUX_SCHED_TASK_H */ |