From b9d1887753998ed4f7feeb52ea2af19e696cd03c Mon Sep 17 00:00:00 2001
From: David du Colombier <0intro@gmail.com>
Date: Mon, 11 Nov 1991 00:00:00 +0000
Subject: [PATCH] Plan 9 from Bell Labs 1991-11-11

---
 port/devproc.c | 19 +++++++++++++++----
 port/portfns.h |  1 +
 power/dat.h    |  2 +-
 power/fns.h    |  1 -
 power/trap.c   |  4 ++--
 ss/clock.c     |  3 +--
 ss/dat.h       |  1 +
 ss/trap.c      | 25 ++++++++++++++++---------
 8 files changed, 37 insertions(+), 19 deletions(-)

diff --git a/port/devproc.c b/port/devproc.c
index f71bb4a1d74cbba46130f132ad6c4f306ac409b5..a7fefbf75de6285630986a7d90da4ab91332a9a4 100644
--- a/port/devproc.c
+++ b/port/devproc.c
@@ -306,6 +306,8 @@ procread(Chan *c, void *va, long n, ulong offset)
 			memmove(&up->note[0], &up->note[1], up->nnote*sizeof(Note));
 			n = ERRLEN;
 		}
+		if(up->nnote == 0)
+			p->notepending = 0;
 		kunmap(k);
 		poperror();
 		unlock(&p->debug);
@@ -365,6 +367,7 @@ procwrite(Chan *c, void *va, long n, ulong offset)
 	User *pxu;
 	Page *pg;
 	char *a = va, *b;
+	ulong hi;
 
 	if(c->qid.path & CHDIR)
 		error(Eisdir);
@@ -397,15 +400,23 @@ procwrite(Chan *c, void *va, long n, ulong offset)
 			k = kmap(pg);
 			b = (char*)VA(k);
 			pxu = (User*)b;
-			if(offset < (ulong)pxu->dbgreg || offset+n >= (ulong)pxu->dbgreg+sizeof(Ureg)) {
+			hi = offset+n;
+			/* Check for floating point registers */
+			if(offset >= (ulong)&u->fpsave && hi <= (ulong)&u->fpsave+sizeof(FPsave)){
+				memmove(b+(offset-USERADDR), a, n);
+				break;
+			}
+			/* Check user register set for process at kernel entry */
+			ur = pxu->dbgreg;
+			if(offset < (ulong)ur || hi > (ulong)ur+sizeof(Ureg)) {
 				kunmap(k);
 				errors("bad u-area address");
 			}
-			ur = (Ureg*)(b+((ulong)pxu->dbgreg-USERADDR));
-			setregisters(ur, (char*)pxu+(offset-USERADDR), a, n);
+			ur = (Ureg*)(b+((ulong)ur-USERADDR));
+			setregisters(ur, b+(offset-USERADDR), a, n);
 			kunmap(k);
 		}
-		else
+		else	/* Try user memory segments */
 			n = procctlmemio(p, offset, n, va, 0);
 		break;
 
diff --git a/port/portfns.h b/port/portfns.h
index 17f6e34c599f870ef0552e0a76eed577a2d736c0..8c21a29ac7830ae91b22ae5a816e5aa811ddfafe 100644
--- a/port/portfns.h
+++ b/port/portfns.h
@@ -203,6 +203,7 @@ ulong	segattach(Proc*, ulong, char *, ulong, ulong);
 void	segpage(Segment*, Page*);
 int	setcolor(ulong, ulong, ulong, ulong);
 int	setlabel(Label*);
+void	setregisters(Ureg*, char*, char*, int);
 void	setswapchan(Chan*);
 void	simpleputpage(Page*);
 char*	skipslash(char*);
diff --git a/power/dat.h b/power/dat.h
index 8b0cca27cb0554ea132b0060863cb901248cc40c..438d7907d4b9e86f484a85a75134fb0edae4aea1 100644
--- a/power/dat.h
+++ b/power/dat.h
@@ -213,10 +213,10 @@ struct
 struct User
 {
 	Proc	*p;
+	FPsave	fpsave;			/* address of this is known by db */
 	int	nerrlab;
 	Label	errlab[NERR];
 	char	error[ERRLEN];
-	FPsave	fpsave;			/* address of this is known by db */
 	char	elem[NAMELEN];		/* last name element from namec */
 	Chan	*slash;
 	Chan	*dot;
diff --git a/power/fns.h b/power/fns.h
index 089383b90be81f838509e53284feafe7b4007b3c..6d9749bc80ad53ec1061839ea2be0fe4ef483d11 100644
--- a/power/fns.h
+++ b/power/fns.h
@@ -55,7 +55,6 @@ int	readlog(ulong, char*, ulong);
 void	restfpregs(FPsave*, ulong);
 #define	screenputs
 void	setvmevec(int, void (*)(int));
-void	setregisters(Ureg*, char*, char*, int);
 void	sinit(void);
 uchar*	smap(int, uchar*);
 void	sunmap(int, uchar*);
diff --git a/power/trap.c b/power/trap.c
index 37c0b6334e8045e0bdc6267ce9817e2ba049e645..79d69c0cd2b3013aef43f9818df42d396e83d28e 100644
--- a/power/trap.c
+++ b/power/trap.c
@@ -566,8 +566,8 @@ setvmevec(int v, void (*f)(int))
 	vmevec[v] = f;
 }
 
-/* This routine must save the values of registers the user is not permitted to write from devproc 
- * and the restore them before returning
+/* This routine must save the values of registers the user is not permitted to write
+ * from devproc and the restore the saved values before returning
  */
 void
 setregisters(Ureg *xp, char *pureg, char *uva, int n)
diff --git a/ss/clock.c b/ss/clock.c
index d66bf8ce76810b01f4261026cd0c7130e1624e58..0ed0eae6786144248552367ff19d710f3d70d362 100644
--- a/ss/clock.c
+++ b/ss/clock.c
@@ -67,8 +67,7 @@ clock(Ureg *ur)
 		}
 		if((ur->psr&PSRPSUPER) == 0){
 /*			*(ulong*)(USTKTOP-BY2WD) += TK2MS(1); /**/
-			if(u->nnote)
-				notify(ur);
+			notify(ur);
 		}
 	}
 }
diff --git a/ss/dat.h b/ss/dat.h
index 04d5961903a8276812d9937fb6b503ef7f6be21c..5bf244c7ccab8f5480def5080dd58caea64a7ed7 100644
--- a/ss/dat.h
+++ b/ss/dat.h
@@ -174,6 +174,7 @@ struct User
 	Note	lastnote;
 	int	(*notify)(void*, char*);
 	void	*ureg;
+	void	*dbgreg;		/* User registers for debugging in proc */
 };
 
 /*
diff --git a/ss/trap.c b/ss/trap.c
index d58cec59c186e6f9eef9f2eeb1deb2356866c628..cfe85e2087c18e9e903bd44482836d723948fbc6 100644
--- a/ss/trap.c
+++ b/ss/trap.c
@@ -121,6 +121,7 @@ trap(Ureg *ur)
 		default:
 			break;
 		}
+    Error:
 		if(user){
 			spllo();
 			sprint(buf, "sys: trap: pc=0x%lux %s", ur->pc, excname(tbr));
@@ -128,7 +129,6 @@ trap(Ureg *ur)
 				sprint(buf+strlen(buf), " FSR %lux", u->fpsave.fsr);
 			postnote(u->p, 1, buf, NDebug);
 		}else{
-    Error:
 			print("kernel trap: %s pc=0x%lux\n", excname(tbr), ur->pc);
 			dumpregs(ur);
 			for(;;);
@@ -136,10 +136,7 @@ trap(Ureg *ur)
 	}
     Return:
 	if(user) {
-		if(u->p->procctl)
-			procctl(u->p);
-		if(u->nnote)
-			notify(ur);
+		notify(ur);
 		if(u->p->fpstate == FPinactive) {
 			restfpregs(&u->fpsave);
 			u->p->fpstate = FPactive;
@@ -219,6 +216,10 @@ notify(Ureg *ur)
 {
 	ulong sp;
 
+	if(u->p->procctl)
+		procctl(u->p);
+	if(u->nnote == 0)
+		return;
 	lock(&u->p->debug);
 	u->p->notepending = 0;
 	if(u->nnote==0){
@@ -345,9 +346,6 @@ syscall(Ureg *aur)
 	}
 	spllo();
 
-	if(u->p->procctl)
-		procctl(u->p);
-
 	r7 = ur->r7;
 	sp = ur->usp;
 
@@ -382,7 +380,7 @@ syscall(Ureg *aur)
 	u->p->psstate = 0;
 	if(r7 == NOTED)	/* ugly hack */
 		noted(&aur, *(ulong*)(sp+1*BY2WD));	/* doesn't return */
-	if(u->nnote && r7!=FORK){
+	if(u->p->procctl || (u->nnote && r7!=FORK)){
 		ur->r7 = ret;
 		notify(ur);
 	}
@@ -394,3 +392,12 @@ execpc(ulong entry)
 {
 	((Ureg*)UREGADDR)->pc = entry - 4;		/* syscall advances it */
 }
+
+/* This routine must save the values of registers the user is not permitted
+ * to write from devproc and restore them before returning
+ */
+void
+setregisters(Ureg *xp, char *pureg, char *uva, int n)
+{
+	print("setregisters: no idea\n");
+}