X-Git-Url: https://codewiz.org/gitweb?a=blobdiff_plain;f=kern%2Fsem.c;h=6f1a773f23493e333ee31cde3fb48d598ca29a33;hb=9f6832426387c3730bf2c9b6202db9eb8d159f42;hp=9e5905f6ae4db7c34777c0a5b7d04d752ef03d97;hpb=277b540c0764dd376dcf583acdc97a2b2fd3d8e6;p=bertos.git

diff --git a/kern/sem.c b/kern/sem.c
index 9e5905f6..6f1a773f 100755
--- a/kern/sem.c
+++ b/kern/sem.c
@@ -1,9 +1,9 @@
 /*!
  * \file
  * <!--
- * Copyright 2001,2004 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.
+ * Copyright 2001, 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 README.devlib for information.
  * -->
  *
  * \brief Semaphore based synchronization services.
@@ -15,6 +15,24 @@
 
 /*#*
  *#* $Log$
+ *#* Revision 1.10  2005/11/04 16:20:02  bernie
+ *#* Fix reference to README.devlib in header.
+ *#*
+ *#* Revision 1.9  2005/04/11 19:10:28  bernie
+ *#* Include top-level headers from cfg/ subdir.
+ *#*
+ *#* Revision 1.8  2005/01/22 04:20:42  bernie
+ *#* Add integrity checks.
+ *#*
+ *#* Revision 1.7  2004/11/28 23:20:25  bernie
+ *#* Remove obsolete INITLIST macro.
+ *#*
+ *#* Revision 1.6  2004/10/21 10:57:21  bernie
+ *#* Use proc_forbid()/proc_permit().
+ *#*
+ *#* Revision 1.5  2004/10/21 10:48:57  bernie
+ *#* sem_release(): Simplify (made by rasky on scfirm).
+ *#*
  *#* Revision 1.4  2004/08/25 14:12:09  rasky
  *#* Aggiornato il comment block dei log RCS
  *#*
@@ -26,7 +44,6 @@
  *#*
  *#* Revision 1.1  2004/05/23 17:27:00  bernie
  *#* Import kern/ subdirectory.
- *#*
  *#*/
 
 #include "sem.h"
@@ -34,14 +51,22 @@
 #include "proc_p.h"
 #include "signal.h"
 #include "hw.h"
+#include <cfg/debug.h>
+
+INLINE void sem_verify(struct Semaphore *s)
+{
+	LIST_ASSERT_VALID(&s->wait_queue);
+	ASSERT(s->nest_count >= 0);
+	ASSERT(s->nest_count < 128);   // heuristic max
+}
 
 
 /*!
- * \brief Initialize a Semaphore structure
+ * \brief Initialize a Semaphore structure.
  */
 void sem_init(struct Semaphore *s)
 {
-	INITLIST(&s->wait_queue);
+	LIST_INIT(&s->wait_queue);
 	s->owner = NULL;
 	s->nest_count = 0;
 }
@@ -60,19 +85,19 @@ void sem_init(struct Semaphore *s)
  */
 bool sem_attempt(struct Semaphore *s)
 {
-	cpuflags_t flags;
-	DISABLE_IRQSAVE(flags);
+	bool result = false;
 
+	proc_forbid();
+	sem_verify(s);
 	if ((!s->owner) || (s->owner == CurrentProcess))
 	{
 		s->owner = CurrentProcess;
 		s->nest_count++;
-		ENABLE_INTS;
-		return true;
+		result = true;
 	}
+	proc_permit();
 
-	ENABLE_IRQRESTORE(flags);
-	return false;
+	return result;
 }
 
 
@@ -95,35 +120,37 @@ bool sem_attempt(struct Semaphore *s)
  */
 void sem_obtain(struct Semaphore *s)
 {
-	cpuflags_t flags;
-	DISABLE_IRQSAVE(flags);
+	proc_forbid();
+	sem_verify(s);
 
 	/* Is the semaphore already locked by another process? */
 	if (UNLIKELY(s->owner && (s->owner != CurrentProcess)))
 	{
 		/* Append calling process to the wait queue */
 		ADDTAIL(&s->wait_queue, (Node *)CurrentProcess);
-		ENABLE_IRQRESTORE(flags);
 
 		/*
 		 * We will wake up only when the current owner calls
 		 * sem_release(). Then, the semaphore will already
 		 * be locked for us.
 		 */
+		proc_permit();
 		proc_schedule();
 	}
 	else
 	{
+		ASSERT(ISLISTEMPTY(&s->wait_queue));
+
 		/* The semaphore was free: lock it */
 		s->owner = CurrentProcess;
 		s->nest_count++;
-		ENABLE_IRQRESTORE(flags);
+		proc_permit();
 	}
 }
 
 
 /*!
- * \brief Releases a lock on a previously locked semaphore.
+ * \brief Release a lock on a previously locked semaphore.
  *
  * If the nesting count of the semaphore reaches zero,
  * the next process waiting for it will be awaken.
@@ -137,30 +164,30 @@ void sem_obtain(struct Semaphore *s)
  */
 void sem_release(struct Semaphore *s)
 {
-	cpuflags_t flags;
-	DISABLE_IRQSAVE(flags);
+	proc_forbid();
+	sem_verify(s);
+
+	ASSERT(s->owner == CurrentProcess);
 
 	/*
-	 * Decremement nesting count and check if the semaphore
-	 * has been fully unlocked
+	 * Decrement nesting count and check if the semaphore
+	 * has been fully unlocked.
 	 */
 	if (--s->nest_count == 0)
 	{
+		Process *proc;
+
 		/* Disown semaphore */
 		s->owner = NULL;
 
-		/* Anybody still waiting for this semaphore? */
-		if (!ISLISTEMPTY(&s->wait_queue))
+		/* Give semaphore to the first applicant, if any */
+		if (UNLIKELY((proc = (Process *)REMHEAD(&s->wait_queue))))
 		{
-			/* Give semaphore to the first applicant */
-			Process *proc = (Process *)s->wait_queue.head;
-			REMOVE((Node *)proc);
 			s->nest_count = 1;
 			s->owner = proc;
 			SCHED_ENQUEUE(proc);
 		}
 	}
 
-	ENABLE_IRQRESTORE(flags);
+	proc_permit();
 }
-