Function syscall_handler

kernel/generic/src/syscall/syscall.c:139–198

Dispatch system call */

/** Dispatch system call */
sysarg_t syscall_handler(sysarg_t a1, sysarg_t a2, sysarg_t a3,
    sysarg_t a4, sysarg_t a5, sysarg_t a6, sysarg_t id)
{
	/* Do userpace accounting */
	irq_spinlock_lock(&THREAD->lock, true);
	thread_update_accounting(true);
	irq_spinlock_unlock(&THREAD->lock, true);

#ifdef CONFIG_UDEBUG
	/*
	 * An istate_t-compatible record was created on the stack by the
	 * low-level syscall handler. This is the userspace space state
	 * structure.
	 */
	THREAD->udebug.uspace_state = istate_get(THREAD);

	/*
	 * Early check for undebugged tasks. We do not lock anything as this
	 * test need not be precise in either direction.
	 */
	if (THREAD->udebug.active)
		udebug_syscall_event(a1, a2, a3, a4, a5, a6, id, 0, false);
#endif

	sysarg_t rc;
	if (id < sizeof_array(syscall_table)) {
		rc = syscall_table[id](a1, a2, a3, a4, a5, a6);
	} else {
		log(LF_OTHER, LVL_ERROR,
		    "Task %" PRIu64 ": Unknown syscall %#" PRIxn, TASK->taskid, id);
		task_kill_self(true);
	}

	if (THREAD->interrupted)
		thread_exit();

#ifdef CONFIG_UDEBUG
	if (THREAD->udebug.active) {
		udebug_syscall_event(a1, a2, a3, a4, a5, a6, id, rc, true);

		/*
		 * Stopping point needed for tasks that only invoke
		 * non-blocking system calls. Not needed if the task
		 * is not being debugged (it cannot block here).
		 */
		udebug_stoppable_begin();
		udebug_stoppable_end();
	}

	/* Clear userspace state pointer */
	THREAD->udebug.uspace_state = NULL;
#endif

	/* Do kernel accounting */
	irq_spinlock_lock(&THREAD->lock, true);
	thread_update_accounting(false);
	irq_spinlock_unlock(&THREAD->lock, true);