+++ /dev/null
-/*!
- * \file
- * <!--
- * Copyright 2004 Develer S.r.l. (http://www.develer.com/)
- * Copyright 1999, 2000, 2001 Bernardo Innocenti <bernie@develer.com>
- * This file is part of DevLib - See devlib/README for information.
- * -->
- *
- * \brief IPC signals implementation.
- *
- * Signals are a low-level IPC primitive. A process receives a signal
- * when some external event has happened. Like interrupt requests,
- * signals do not carry any additional information. If processing a
- * specific event requires additional data, the process must obtain it
- * through some other mechanism.
- *
- * Despite the name, one shouldn't confuse these signals with POSIX
- * signals. POSIX signals are usually executed synchronously, like
- * software interrupts.
- *
- * In this implementation, each process has a limited set of signal
- * bits (usually 32) and can wait for multiple signals at the same
- * time using sig_wait(). Signals can also be polled using sig_check(),
- * but a process spinning on its signals usually defeats their purpose
- * of providing a multitasking-friendly infrastructure for event-driven
- * applications.
- *
- * Signals are like flags: they are either active or inactive. After an
- * external event has delivered a particular signal, it remains raised until
- * the process acknowledges it using either sig_wait() or sig_check().
- * Counting signals is not a reliable way to count how many times a
- * particular event has occurred, because the same signal may be
- * delivered twice before the process can notice.
- *
- * Any execution context, including an interrupt handler, can deliver
- * a signal to a process using sig_signal(). Multiple distinct signals
- * may be delivered at once with a single invocation of sig_signal(),
- * although this is rarely useful.
- *
- * There's no hardcoded mapping of specific events to signal bits.
- * The meaning of a particular signal bit is defined by an agreement
- * between the delivering entity and the receiving process.
- * For instance, a terminal driver may be written to deliver
- * a signal bit called SIG_INT when it reads the CTRL-C sequence
- * from the keyboard, and a process may react to it by quitting.
- *
- * The SIG_SINGLE bit is reserved for a special purpose (this is
- * more a suggestion than a constraint). When a process wants
- * wait for a single event on the fly, it needs not allocate a
- * free signal from its pool. Instead, SIG_SINGLE can be used
- *
- * The "event" module is a higher-level interface that can optionally
- * deliver signals to processes. Messages provide even higher-level
- * IPC services built on signals. Semaphore arbitration is also
- * implemented using signals.
- *
- * Signals are very low overhead. Using them exclusively to wait
- * for multiple asynchronous events results in very simple dispatch
- * logic with low processor and resource usage.
- *
- *
- * \version $Id$
- *
- * \author Bernardo Innocenti <bernie@develer.com>
- */
-
-/*#*
- *#* $Log$
- *#* Revision 1.8 2004/09/14 21:06:44 bernie
- *#* Use debug.h instead of kdebug.h.
- *#*
- *#* Revision 1.7 2004/08/25 14:12:09 rasky
- *#* Aggiornato il comment block dei log RCS
- *#*
- *#* Revision 1.6 2004/08/14 19:37:57 rasky
- *#* Merge da SC: macros.h, pool.h, BIT_CHANGE, nome dei processi, etc.
- *#*
- *#* Revision 1.5 2004/08/04 21:50:33 bernie
- *#* Add extensive documentation.
- *#*
- *#* Revision 1.4 2004/07/30 14:30:27 rasky
- *#* Resa la sig_signal interrupt safe (con il nuovo scheduler IRQ-safe)
- *#* Rimossa event_doIntr (ora inutile) e semplificata la logica delle macro con funzioni inline
- *#*
- *#* Revision 1.3 2004/07/30 14:24:16 rasky
- *#* Task switching con salvataggio perfetto stato di interrupt (SR)
- *#* Kernel monitor per dump informazioni su stack dei processi
- *#*
- *#* Revision 1.2 2004/06/03 11:27:09 bernie
- *#* Add dual-license information.
- *#*
- *#* Revision 1.1 2004/05/23 17:27:00 bernie
- *#* Import kern/ subdirectory.
- *#*
- *#*/
-
-#include "signal.h"
-#include "proc.h"
-#include "proc_p.h"
-#include "hw.h"
-#include <debug.h>
-
-// FIXME
-#if CONFIG_KERN_SIGNALS
-
-/*!
- * Check if any of the signals in \a sigs has occurred and clear them.
- * Return the signals that have occurred.
- */
-sigset_t sig_check(sigset_t sigs)
-{
- sigset_t result;
- cpuflags_t flags;
-
- DISABLE_IRQSAVE(flags);
- result = CurrentProcess->sig_recv & sigs;
- CurrentProcess->sig_recv &= ~sigs;
- ENABLE_IRQRESTORE(flags);
- return result;
-}
-
-
-/*!
- * Sleep until any of the signals in \a sigs occurs.
- * Return the signal(s) that have awaked the process.
- */
-sigset_t sig_wait(sigset_t sigs)
-{
- sigset_t result;
- cpuflags_t flags;
-
- DISABLE_IRQSAVE(flags);
-
- /* Loop until we get at least one of the signals */
- while (!(result = CurrentProcess->sig_recv & sigs))
- {
- /* go to sleep and proc_schedule() another process */
- CurrentProcess->sig_wait = sigs;
- proc_schedule();
-
- /* When we come back here, a signal must be arrived */
- ASSERT(!CurrentProcess->sig_wait);
- ASSERT(CurrentProcess->sig_recv);
- }
-
- /* Signals found: clear them and return */
- CurrentProcess->sig_recv &= ~sigs;
- ENABLE_IRQRESTORE(flags);
- return result;
-}
-
-
-/*!
- * Send the signals \a sigs to the process \a proc.
- * The process will be awaken if it was waiting for any of them.
- *
- * \note This call is interrupt safe.
- */
-void sig_signal(Process *proc, sigset_t sigs)
-{
- cpuflags_t flags;
- DISABLE_IRQSAVE(flags);
-
- /* Set the signals */
- proc->sig_recv |= sigs;
-
- /* Check if process needs to be awaken */
- if (proc->sig_recv & proc->sig_wait)
- {
- /* Wake up process and enqueue in ready list */
- proc->sig_wait = 0;
- SCHED_ENQUEUE(proc);
- }
-
- ENABLE_IRQRESTORE(flags);
-}
-
-#endif /* CONFIG_KERN_SIGNALS */
-
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