From f56d2fccc1a8789565beb1d864ec3c25cb2c33d3 Mon Sep 17 00:00:00 2001
From: David du Colombier <0intro@gmail.com>
Date: Thu, 2 Jan 1992 00:00:00 +0000
Subject: [PATCH] Plan 9 from Bell Labs 1992-01-02

---
 port/stip.c  |  3 ++-
 power/dat.h  |  1 +
 power/trap.c | 40 +++++++++++++++++++++-------------------
 ss/dat.h     |  1 +
 ss/trap.c    |  4 +++-
 5 files changed, 28 insertions(+), 21 deletions(-)

diff --git a/port/stip.c b/port/stip.c
index ec381a3ce6b6b524782605c1120289cc80dfc602..a2dd323a7f1c58a89e073cfe0fa4c755a7fd8768 100644
--- a/port/stip.c
+++ b/port/stip.c
@@ -522,7 +522,8 @@ ipfragfree(Fragq *frag)
 {
 	Fragq *fl, **l;
 
-	freeb(frag->blist);
+	if(frag->blist)
+		freeb(frag->blist);
 
 	frag->src = 0;
 	frag->id = 0;
diff --git a/power/dat.h b/power/dat.h
index 4d7839d68ee408c258857e18f2db01a4932f542b..225053d73dc39d0037163c1110802118f3334ba5 100644
--- a/power/dat.h
+++ b/power/dat.h
@@ -232,6 +232,7 @@ struct User
 	void	*ureg;			/* User registers for notes */
 	void	*dbgreg;		/* User registers for debugging in proc */
 	ulong	svstatus;
+	ulong	svr1;
 	/*
 	 *  machine dependent User stuff
 	 */
diff --git a/power/trap.c b/power/trap.c
index e177e022476875496cef3856a100b75f84bd9687..0c86ed21314821a7e1f9392147eeee99d1c8ac8f 100644
--- a/power/trap.c
+++ b/power/trap.c
@@ -26,24 +26,24 @@ void	rfnote(Ureg**);
 
 char *excname[] =
 {
-	"external interrupt",
-	"TLB modification",
-	"TLB miss (load or fetch)",
-	"TLB miss (store)",
-	"address error (load or fetch)",
-	"address error (store)",
-	"bus error (fetch)",
-	"bus error (data load or store)",
-	"system call",
+	"trap: external interrupt",
+	"trap: TLB modification",
+	"trap: TLB miss (load or fetch)",
+	"trap: TLB miss (store)",
+	"trap: address error (load or fetch)",
+	"trap: address error (store)",
+	"trap: bus error (fetch)",
+	"trap: bus error (data load or store)",
+	"trap: system call",
 	"breakpoint",
-	"reserved instruction",
-	"coprocessor unusable",
-	"arithmetic overflow",
-	"undefined 13",
-	"undefined 14",
-	"undefined 15",				/* used as sys call for debugger */
+	"trap: reserved instruction",
+	"trap: coprocessor unusable",
+	"trap: arithmetic overflow",
+	"trap: undefined 13",
+	"trap: undefined 14",
+	"trap: undefined 15",				/* used as sys call for debugger */
 	/* the following is made up */
-	"floating point exception"		/* FPEXC */
+	"trap: floating point exception"		/* FPEXC */
 };
 char	*fpexcname(ulong);
 
@@ -152,7 +152,7 @@ trap(Ureg *ur)
 			if(ecode == FPEXC)
 				sprint(buf, "sys: fp: %s FCR31 %lux", fpexcname(x), x);
 			else
-				sprint(buf, "sys: trap: %s", excname[ecode]);
+				sprint(buf, "sys: %s", excname[ecode]);
 
 			postnote(u->p, 1, buf, NDebug);
 		}else{
@@ -413,7 +413,7 @@ notify(Ureg *ur)
 		memmove((char*)sp, u->note[0].msg, ERRLEN);
 		sp -= 3*BY2WD;
 		*(ulong*)(sp+2*BY2WD) = sp+3*BY2WD;	/* arg 2 is string */
-		*(ulong*)(sp+1*BY2WD) = (ulong)u->ureg;	/* arg 1 is ureg* */
+		ur->r1 = (ulong)u->ureg;		/* arg 1 is ureg* */
 		*(ulong*)(sp+0*BY2WD) = 0;		/* arg 0 is pc */
 		ur->usp = sp;
 		ur->pc = (ulong)u->notify;
@@ -448,6 +448,7 @@ noted(Ureg **urp, ulong arg0)
 	}
 	u->notified = 0;
 	memmove(*urp, u->ureg, sizeof(Ureg));
+	(*urp)->r1 = u->svr1;
 	switch(arg0){
 	case NCONT:
 		if(waserror()){
@@ -542,8 +543,9 @@ syscall(Ureg *aur)
 		noted(&aur, *(ulong*)(sp+BY2WD));	/* doesn't return */
 	splhi();
 	if(r1!=FORK && (u->p->procctl || u->nnote)){
-		ur->r1 = ret;
+		u->svr1 = ret;
 		notify(ur);
+		return ur->r1;
 	}
 
 	return ret;
diff --git a/ss/dat.h b/ss/dat.h
index d5b13b2fb8594d7d3549af4d82da22383afb490e..f7fa9dd6580191bd7a2690fcfef2b3d7bdca5629 100644
--- a/ss/dat.h
+++ b/ss/dat.h
@@ -177,6 +177,7 @@ struct User
 	int	(*notify)(void*, char*);
 	void	*ureg;
 	void	*dbgreg;		/* User registers for debugging in proc */
+	ulong	svr7;
 };
 
 /*
diff --git a/ss/trap.c b/ss/trap.c
index 4ca1849a90b5eb821557095b020ab6c1ca14fc6e..677b424b0edf31528df1ecdb514e1795e8dcb727 100644
--- a/ss/trap.c
+++ b/ss/trap.c
@@ -312,6 +312,7 @@ noted(Ureg **urp, ulong arg0)
 	}
 	u->notified = 0;
 	memmove(*urp, u->ureg, sizeof(Ureg));
+	(*urp)->r7 = u->svr7;
 	switch(arg0){
 	case NCONT:
 		if(waserror()){
@@ -406,8 +407,9 @@ syscall(Ureg *aur)
 
 	splhi();
 	if(r7!=FORK && (u->p->procctl || u->nnote)){
-		ur->r7 = ret;
+		u->svr7 = ret;
 		notify(ur);
+		return ur->r7;
 	}
 	return ret;
 }