From 1dfe5a59f356506276df9ce446f1a2951407b6f5 Mon Sep 17 00:00:00 2001
From: David du Colombier <0intro@gmail.com>
Date: Tue, 9 Apr 2002 00:00:00 +0000
Subject: [PATCH] Plan 9 from Bell Labs 2002-04-09

---
 boot/bootip.c  |  2 ++
 pc/devarch.c   |  2 +-
 pc/i8253.c     | 57 +++++++++++++++++++++++++-------------------------
 pc/mp.c        |  2 --
 pc/vganvidia.c |  1 +
 port/devenv.c  |  4 +++-
 6 files changed, 35 insertions(+), 33 deletions(-)

diff --git a/boot/bootip.c b/boot/bootip.c
index 867de5344e55b8822e629ce1a32cafc4b8878a9f..c330f8666a13577401a7ddec925175b21cae4b4d 100644
--- a/boot/bootip.c
+++ b/boot/bootip.c
@@ -52,6 +52,8 @@ configip(void)
 	bind("#I", mpoint, MAFTER);
 	bind("#l0", mpoint, MAFTER);
 	bind("#l1", mpoint, MAFTER);
+	bind("#l2", mpoint, MAFTER);
+	bind("#l3", mpoint, MAFTER);
 
 	/* let ipconfig configure the ip interface */
 	switch(pid = fork()){
diff --git a/pc/devarch.c b/pc/devarch.c
index e4ee7a0fbb7f758b85634d28aa84c4d78b4411cf..f652e5293c4fa1b2391f0c30844dabfba61891e4 100644
--- a/pc/devarch.c
+++ b/pc/devarch.c
@@ -734,7 +734,7 @@ archinit(void)
 	if(X86FAMILY(m->cpuidax) == 3 || conf.nmach > 1)
 		conf.copymode = 1;
 
-	if(X86FAMILY(m->cpuidax) >= 5)
+	if(X86FAMILY(m->cpuidax) >= 5 && conf.nmach > 1)
 		coherence = wbflush;
 
 	addarchfile("cputype", 0444, cputyperead, nil);
diff --git a/pc/i8253.c b/pc/i8253.c
index 3d88279b4cf9319dea4bac08d399da325da8b954..bb40090d7e238a81668fb67cc0c6f636fbc6797d 100644
--- a/pc/i8253.c
+++ b/pc/i8253.c
@@ -51,7 +51,13 @@ enum
 	C2speak=0x2,
 	C2out=	0x10,
 
+	/* T2ctl bits */
+	T2gate=	(1<<0),		/* enable T2 counting */
+	T2spkr=	(1<<1),		/* connect T2 out to speaker */
+	T2out=	(1<<5),		/* output of T2 */
+
 	Freq=	1193182,	/* Real clock frequency */
+	Tickshift= 8,		/* increase tick wriggle room */
 
 	Minusec=20,		/* minimum cycles for a clock interrupt */
 
@@ -68,9 +74,8 @@ static struct
 	long	fastperiod;	/* fastticks/hz */
 	long	fast2freq;	/* fastticks*FreqMul/Freq */
 
-	Lock	lock1;		/* mutex for the following */
-	ushort	last1;		/* last value of clock 1 */
-	uvlong	ticks1;		/* cumulative ticks of counter 1 */
+	ushort	last;		/* last value of clock 1 */
+	uvlong	ticks;		/* cumulative ticks of counter 1 */
 }i8253;
 
 void
@@ -90,12 +95,14 @@ i8253init(void)
 	outb(T0cntr, (Freq/HZ)>>8);	/* high byte */
 
 	/*
-	 *  set time clock
+	 *  enable a longer period counter to use as a clock
 	 */
-	outb(Tmode, Load1|Square);
-	i8253.mode = Square;
-	outb(T1cntr, 0xfe);	/* low byte */
-	outb(T1cntr, 0xff);	/* high byte */
+	outb(Tmode, Load2|Square);
+	outb(T2cntr, 0);		/* low byte */
+	outb(T2cntr, 0);		/* high byte */
+	x = inb(T2ctl);
+	x |= T2gate;
+	outb(T2ctl, x);
 
 	/*
 	 * Introduce a little delay to make sure the count is
@@ -241,8 +248,6 @@ clockintrsched(void)
 	iunlock(&i8253);
 }
 
-ulong i8253ding[2];
-
 static void
 clockintr0(Ureg* ureg, void *v)
 {
@@ -255,12 +260,6 @@ clockintr0(Ureg* ureg, void *v)
 	now = fastticks(nil);
 	when = i8253.when;
 
-if(i8253.last1 == 0 || i8253.last1 >= 0xffe0)
-	i8253ding[1]++;
-else
-	i8253ding[0]++;
-	
-
 	if(now >= i8253.when){
 		clockintr(ureg, v);
 		do
@@ -295,23 +294,23 @@ i8253read(uvlong *hz)
 	uvlong ticks;
 
 	if(hz)
-		*hz = Freq<<8;
+		*hz = Freq<<Tickshift;
 
-	ilock(&i8253.lock1);
-	outb(Tmode, Latch1);
-	y = inb(T1cntr);
-	y |= inb(T1cntr)<<8;
+	ilock(&i8253);
+	outb(Tmode, Latch2);
+	y = inb(T2cntr);
+	y |= inb(T2cntr)<<8;
 
-	if(y < i8253.last1)
-		x = i8253.last1 - y;
+	if(y < i8253.last)
+		x = i8253.last - y;
 	else
-		x = i8253.last1 + (0xfffe - y);
-	i8253.last1 = y;
-	i8253.ticks1 += x>>1;
-	ticks = i8253.ticks1;
-	iunlock(&i8253.lock1);
+		x = i8253.last + (0x1000 - y);
+	i8253.last = y;
+	i8253.ticks += x>>1;
+	ticks = i8253.ticks;
+	iunlock(&i8253);
 
-	return ticks<<8;
+	return ticks<<Tickshift;
 }
 
 /*
diff --git a/pc/mp.c b/pc/mp.c
index c4b93ea10237975d8096865e3ea2b69db06f841f..0178e8edd8b41db143e0604d6367a1c82e826dd6 100644
--- a/pc/mp.c
+++ b/pc/mp.c
@@ -48,8 +48,6 @@ apicclkenable(void)
 {
 	Apic *apic;
 
-	i8259init();
-
 	/* Uniprocessor local apic init for apic clock */
 	apic = &mpapic[0];
 	apic->type = PcmpPROCESSOR;
diff --git a/pc/vganvidia.c b/pc/vganvidia.c
index 95c567c57493d7c190afde381999f41cbf638c5c..f99450e6cacee5a6d921755b3f386efff607d4b3 100644
--- a/pc/vganvidia.c
+++ b/pc/vganvidia.c
@@ -42,6 +42,7 @@ static ushort nvidiadid[] = {
 	0x0151,		/* GeForce2 GTS (rev 1) */
 	0x0152,		/* GeForce2 Ultra */
 	0x0153,		/* Quadro 2 Pro */
+	0x0200,		/* GeForce3 */
 	0,
 };
 
diff --git a/port/devenv.c b/port/devenv.c
index a3705aa8120ba0152d430e3540ffb12adc3c894c..bf6678038285fc612e7c7f6e7889d65cb888f871 100644
--- a/port/devenv.c
+++ b/port/devenv.c
@@ -232,7 +232,9 @@ envread(Chan *c, void *a, long n, vlong off)
 		error(Enonexist);
 	}
 
-	if(offset + n > e->len)
+	if(offset > e->len)	/* protects against overflow converting vlong to ulong */
+		n = 0;
+	else if(offset + n > e->len)
 		n = e->len - offset;
 	if(n <= 0)
 		n = 0;