Restructure and document a bit. Also fixed a confusing bug, which

actually might turn out a feature... :-)  But I want to test that a
bit more before having that into the tree.

1 files changed, 60 insertions, 29 deletions

diff --git a/sys/arch/amiga/include/psl.h b/sys/arch/amiga/include/psl.h
index 708b63887e8..16ff7fbaa84 100644
--- a/sys/arch/amiga/include/psl.h
+++ b/sys/arch/amiga/include/psl.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: psl.h,v 1.5 1996/05/02 07:33:43 niklas Exp $	*/
+/*	$OpenBSD: psl.h,v 1.6 1996/05/07 10:22:45 niklas Exp $	*/
 /*	$NetBSD: psl.h,v 1.8 1996/04/21 21:13:22 veego Exp $	*/
 
 #ifndef _MACHINE_PSL_H_
@@ -14,60 +14,85 @@ splraise(npsl)
 {
         register int opsl;
 
+        __asm __volatile ("clrl %0; movew sr,%0" : "&=d" (opsl) : : "cc");
+	if (npsl > (opsl & (PSL_S|PSL_IPL)))
+        	__asm __volatile ("movew %0,sr" : : "di" (npsl) : "cc");
+        return opsl;
+}
+
+static __inline int
+splexact(npsl)
+	register int npsl;
+{
+        register int opsl;
+
         __asm __volatile ("clrl %0; movew sr,%0; movew %1,sr" : "&=d" (opsl) :
-	    "di" (npsl));
+	    "di" (npsl) : "cc");
         return opsl;
 }
 
-#ifdef IPL_REMAP_1
+#if !defined(IPL_REMAP_1) && !defined(IPL_REMAP_2)
+static __inline void
+splx(npsl)
+	register int npsl;
+{
+        __asm __volatile ("movew %0,sr" : : "di" (npsl) : "cc");
+}
+#endif
 
+#ifdef IPL_REMAP_1
 extern int isr_exter_ipl;
 extern void walk_ipls __P((int, int));
 
-static __inline int
+static __inline void
 splx(npsl)
 	register int npsl;
 {
-        register int opsl;
-
-        __asm __volatile ("clrl %0; movew sr,%0" : "=d" (opsl));
+/*
+ * XXX This is scary as hell.  Actually removing this increases performance
+ * XXX while functionality remains.  However fairness of service is altered.
+ * XXX Potential lower priority services gets serviced before higher ones.
+ */
 	if ((isr_exter_ipl << 8) > (npsl & PSL_IPL))
 		walk_ipls(isr_exter_ipl, npsl);
-        __asm __volatile("movew %0,sr" : : "di" (npsl));
-        return opsl;
+        __asm __volatile("movew %0,sr" : : "di" (npsl) : "cc");
 }
 #endif
 
-#ifndef IPL_REMAP_2
-#define splx splraise
-#else
-
+#ifdef IPL_REMAP_2
 extern int walk_ipls __P((int));
 
-static __inline int
+static __inline void
 splx(npsl)
 	register int npsl;
 {
+	/* We should maybe have a flag telling if this is needed.  */
+	walk_ipls(npsl);
+        __asm __volatile("movew %0,sr" : : "di" (npsl) : "cc");
+}
+#endif
+
+static __inline int
+spllower(npsl)
+	register int npsl;
+{
         register int opsl;
 
-	/* We should maybe have a flag telling if this is needed.  */
-	opsl = walk_ipls(npsl);
-        __asm __volatile("movew %0,sr" : : "di" (npsl));
+        __asm __volatile ("clrl %0; movew sr,%0" : "&=d" (opsl) : : "cc");
+        splx(npsl);
         return opsl;
 }
 
-#endif
-
 /*
- * Shortcuts
+ * Shortcuts.  For enhanced security use splraise instead of splexact.
  */
-#define spl1()	splraise(PSL_S|PSL_IPL1)
-#define spl2()	splraise(PSL_S|PSL_IPL2)
-#define spl3()	splraise(PSL_S|PSL_IPL3)
-#define spl4()	splraise(PSL_S|PSL_IPL4)
-#define spl5()	splraise(PSL_S|PSL_IPL5)
-#define spl6()	splraise(PSL_S|PSL_IPL6)
-#define spl7()  splraise(PSL_S|PSL_IPL7)
+#define spl1()		splexact(PSL_S|PSL_IPL1)
+#define spl2()		splexact(PSL_S|PSL_IPL2)
+#define spl3()		splexact(PSL_S|PSL_IPL3)
+#define spl4()		splexact(PSL_S|PSL_IPL4)
+#define spl5()		splexact(PSL_S|PSL_IPL5)
+#define spl6()		splexact(PSL_S|PSL_IPL6)
+#define spl7()  	splexact(PSL_S|PSL_IPL7)
 
 /*
  * Hardware interrupt masks
@@ -89,19 +114,25 @@ splx(npsl)
  * NOTE: splsoftclock() is used by hardclock() to lower the priority from
  * clock to softclock before it calls softclock().
  */
-#define splsoftclock()	splx(PSL_S|PSL_IPL1)
+#define splsoftclock()	spllower(PSL_S|PSL_IPL1)
 #define splsoftnet()	spl1()
 #define splsofttty()	spl1()
 
 /*
  * Miscellaneous
  */
+
+/*
+ * When remapping high interrupts down we also pull down splhigh, so that
+ * the fast internal serial interrupt can get called allover.  This is safe
+ * as this interrupt never goes outside of its own structures.
+ */
 #if defined(LEV6_DEFER) || defined(IPL_REMAP_1) || defined(IPL_REMAP_2)
 #define splhigh()	spl4()
 #else
 #define splhigh()	spl7()
 #endif
-#define spl0()	splx(PSL_S|PSL_IPL0)
+#define spl0()		spllower(PSL_S|PSL_IPL0)
 
 #endif	/* KERNEL && !_LOCORE */
 #endif	/* _MACHINE_PSL_H_ */