X-Git-Url: https://codewiz.org/gitweb?a=blobdiff_plain;f=kern%2Fsignal.c;h=71ccf67ada7dd6090ecc5a1420a7580567dda67d;hb=HEAD;hp=3e6fd1cbf725ba394a169325609516eb38648158;hpb=5f3952176a4e9a00ca8dd5ec4a6b994958f89e0a;p=bertos.git diff --git a/kern/signal.c b/kern/signal.c deleted file mode 100644 index 3e6fd1cb..00000000 --- a/kern/signal.c +++ /dev/null @@ -1,198 +0,0 @@ -/** - * \file - * - * - * \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 - */ - -/*#* - *#* $Log$ - *#* Revision 1.14 2006/07/19 12:56:27 bernie - *#* Convert to new Doxygen style. - *#* - *#* Revision 1.13 2006/02/24 01:17:05 bernie - *#* Update for new emulator. - *#* - *#* Revision 1.12 2005/11/04 16:20:02 bernie - *#* Fix reference to README.devlib in header. - *#* - *#* Revision 1.11 2005/04/11 19:10:28 bernie - *#* Include top-level headers from cfg/ subdir. - *#* - *#* Revision 1.10 2004/12/13 12:07:06 bernie - *#* DISABLE_IRQSAVE/ENABLE_IRQRESTORE: Convert to IRQ_SAVE_DISABLE/IRQ_RESTORE. - *#* - *#* Revision 1.9 2004/12/08 08:57:35 bernie - *#* Rename sigset_t to sigmask_t. - *#* - *#* 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 -#include -#include - -#if CONFIG_KERN_SIGNALS - -/** - * Check if any of the signals in \a sigs has occurred and clear them. - * Return the signals that have occurred. - */ -sigmask_t sig_check(sigmask_t sigs) -{ - sigmask_t result; - cpuflags_t flags; - - IRQ_SAVE_DISABLE(flags); - result = CurrentProcess->sig_recv & sigs; - CurrentProcess->sig_recv &= ~sigs; - IRQ_RESTORE(flags); - - return result; -} - - -/** - * Sleep until any of the signals in \a sigs occurs. - * Return the signal(s) that have awaked the process. - */ -sigmask_t sig_wait(sigmask_t sigs) -{ - sigmask_t result; - cpuflags_t flags; - - IRQ_SAVE_DISABLE(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; - - IRQ_RESTORE(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, sigmask_t sigs) -{ - cpuflags_t flags; - IRQ_SAVE_DISABLE(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); - } - - IRQ_RESTORE(flags); -} - -#endif /* CONFIG_KERN_SIGNALS */ -