Process Level Activities
[Linux DDE Common]

This module emulates the process level environment inside the Linux kernel. More...

Scheduling Primitives
To circumvent real user-level threads and scheduling we support only sane user context states generated by bug-free drivers. The task structure has a new member - dde_sem binary semaphore - and each process could sleep on this until awakened by any event. This is from kernel/%sched.c
int	FASTCALL (wake_up_process(struct task_struct *p))
	Wake up dedicated user context.
signed long	FASTCALL (schedule_timeout(signed long timeout))
	Schedule process but wake me at least after timeout.
void	schedule (void)
	Schedule process.
void	FASTCALL (__wake_up(wait_queue_head_t *q, unsigned int mode, int nr))
	Wake up wait queue entries.
void	FASTCALL (__wake_up_sync(wait_queue_head_t *q, unsigned int mode, int nr))
	Wake up wait queue entries (sync).
void	FASTCALL (interruptible_sleep_on(wait_queue_head_t *q))
	Sleep on wait queue (interruptible by signals).
long	FASTCALL (interruptible_sleep_on_timeout(wait_queue_head_t *q, long timeout))
	Sleep on wait queue (interruptible by signals and timeout).
void	FASTCALL (sleep_on(wait_queue_head_t *q))
	Sleep on wait queue.
long	FASTCALL (sleep_on_timeout(wait_queue_head_t *q, long timeout))
	Sleep on wait queue (interruptible by timeout).
void	daemonize (void)
	Put all the gunge required to become a kernel thread without attached user resources in one place where it belongs.
Wait Queue - List Manipulation
This is from kernel/fork.c
void	FASTCALL (add_wait_queue(wait_queue_head_t *q, wait_queue_t *wait))
	Enqueue process in wait queue.
void	FASTCALL (add_wait_queue_exclusive(wait_queue_head_t *q, wait_queue_t *wait))
	Enqueue process in wait queue (exclusive flag set).
void	FASTCALL (remove_wait_queue(wait_queue_head_t *q, wait_queue_t *wait))
	Dequeue process from wait queue.
Functions
task_struct *	get_current ()
	Get pointer to current task structure.
int	l4dde_process_add_worker ()
	Add caller as new process level worker.
int	l4dde_process_init ()
	Initalize process module.
long	kernel_thread (int(*fn)(void *), void *arg, unsigned long flags)
	Create kernel thread.

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Detailed Description

This module emulates the process level environment inside the Linux kernel.

It provides one task structure (PCB) per worker (L4-)thread. Functions like schedule(), sleep_on() and wake_up() rely on this. Kernel threads are also implemented here.

Requirements: (additionally to Global Requirements)

• Linux DDE Memory Management Module

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Function Documentation

void daemonize (  void   )

Put all the gunge required to become a kernel thread without attached user resources in one place where it belongs. (dummy) Definition at line 262 of file sched.c. References DEBUG_MSG.

struct task_struct* get_current (   )

Get pointer to current task structure. This replaces the "current" macro Test: krishna: What about "current" derefences from irqs and softirqs? Are they all eliminated? Definition at line 61 of file process.c. References _key.

int l4dde_process_add_worker (   )

Add caller as new process level worker. Returns: 0 on success; negative error code otherwise This allocates and initializes a new task_struct for the worker thread. Definition at line 75 of file process.c. References _data, _key, and vmalloc(). Referenced by __start_kernel_thread(), dde_irq_thread(), dde_softirq_thread(), and dde_timer_thread().

int l4dde_process_init (   )

Initalize process module. Returns: 0 on success; negative error code otherwise Initializes process level emulation environment and adds caller as first and only worker thread. Additional threads can be used after calling l4dde_process_add_worker() in new thread's context. Definition at line 109 of file process.c. References _data, _initialized, _key, and vmalloc().

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