From ee5b1de1db9d8e1cb7635acbc71897fb2a7d0623 Mon Sep 17 00:00:00 2001
From: David du Colombier <0intro@gmail.com>
Date: Fri, 21 Sep 1990 00:00:00 +0000
Subject: [PATCH] Plan 9 from Bell Labs 1990-09-21

---
 gnot/dat.h     | 17 +++++++++++++++++
 gnot/fns.h     |  1 +
 gnot/main.c    |  2 ++
 gnot/mmu.c     | 44 ++++++++++++++++++++++++++++++++++++++++++++
 gnot/proc.c    |  1 +
 gnot/sysproc.c |  2 ++
 6 files changed, 67 insertions(+)

diff --git a/gnot/dat.h b/gnot/dat.h
index 0cb7c68fc0be883661ee8dbe6c7f7974ae7b9a82..579dfe2f0903ee91a847a971791a6060c514c2b5 100644
--- a/gnot/dat.h
+++ b/gnot/dat.h
@@ -16,6 +16,8 @@ typedef struct KMap	KMap;
 typedef struct Label	Label;
 typedef struct List	List;
 typedef struct Lock	Lock;
+typedef struct MMU	MMU;
+typedef struct MMUCache	MMUCache;
 typedef struct Mach	Mach;
 typedef struct Mount	Mount;
 typedef struct Mtab	Mtab;
@@ -337,6 +339,20 @@ struct Proc
 	ulong	pc;			/* DEBUG only */
 };
 
+struct MMU
+{
+	ulong	va;
+	ulong	pa;
+	int	pid;
+};
+
+#define NMMU 16
+struct MMUCache
+{
+	ulong	next;
+	MMU	mmu[NMMU];
+};
+
 #define	NERR	15
 #define	NNOTE	5
 #define	NFD	100
@@ -360,6 +376,7 @@ struct User
 	short	nnote;
 	short	notified;		/* sysnoted is due */
 	int	(*notify)(void*, char*);
+	MMUCache mc;
 	void	*ureg;
 };
 
diff --git a/gnot/fns.h b/gnot/fns.h
index 1cb1920aeb49e3d3c011c1294c733a2ed43880c6..872f3597e3681d9c9d4d7bc3208adcce176d1bc0 100644
--- a/gnot/fns.h
+++ b/gnot/fns.h
@@ -51,6 +51,7 @@ void	firmware(void);
 void	flowctl(Queue*);
 void	flushcpucache(void);
 void	flushmmu(void);
+void	flushmmucache(void);
 void	forkmod(Seg*, Seg*, Proc*);
 int	fpcr(int);
 void	fpsave(FPsave*);
diff --git a/gnot/main.c b/gnot/main.c
index cafe974bab99b314c1729b306e4ab53fcea9fa20..b33e1ba9444ed43ea825f818b268c4ae1215b2ce 100644
--- a/gnot/main.c
+++ b/gnot/main.c
@@ -31,6 +31,7 @@ void unloadboot(void);
 void
 main(void)
 {
+	u = 0;
 	unloadboot();
 	machinit();
 	mmuinit();
@@ -154,6 +155,7 @@ userinit(void)
 	k = kmap(p->upage);
 	up = (User*)VA(k);
 	up->p = p;
+	up->mc.next = 0;
 	kunmap(k);
 
 	/*
diff --git a/gnot/mmu.c b/gnot/mmu.c
index 3c90915cb6786d38eb360325a61daaceb5d67959..f0f6d4020c7c89b046deb007d7dd1a8f6ebb2432 100644
--- a/gnot/mmu.c
+++ b/gnot/mmu.c
@@ -12,6 +12,17 @@ struct
 	KMap	arena[4*1024*1024/BY2PG];	/* kernel mmu maps up to 4MB */
 }kmapalloc;
 
+void
+putxmmu(ulong tlbvirt, ulong tlbphys, int pid)
+{
+	if(pid != u->p->pid)
+		panic("putxmmu %ld %ld\n", pid, u->p->pid);
+	if(tlbvirt&KZERO)
+		panic("putmmu");
+	tlbphys |= VTAG(tlbvirt)<<24;
+	UMAP[(tlbvirt&0x003FE000L)>>2] = tlbphys;
+}
+
 /*
  * Called splhi, not in Running state
  */
@@ -19,6 +30,7 @@ void
 mapstack(Proc *p)
 {
 	ulong tlbvirt, tlbphys;
+	ulong i;
 
 	if(p->upage->va != (USERADDR|(p->pid&0xFFFF)))
 		panic("mapstack %d 0x%lux 0x%lux", p->pid, p->upage->pa, p->upage->va);
@@ -27,6 +39,14 @@ mapstack(Proc *p)
 	putkmmu(tlbvirt, tlbphys);
 	flushmmu();
 	u = (User*)USERADDR;
+
+	if(u->mc.next >= NMMU){
+		u->mc.next &= NMMU - 1;
+		for(i = u->mc.next; i < NMMU; i++)
+			putxmmu(u->mc.mmu[i].va, u->mc.mmu[i].pa, u->mc.mmu[i].pid);
+	}
+	for(i = 0; i < u->mc.next; i++)
+		putxmmu(u->mc.mmu[i].va, u->mc.mmu[i].pa, u->mc.mmu[i].pid);/**/
 }
 
 void
@@ -43,6 +63,14 @@ putmmu(ulong tlbvirt, ulong tlbphys)
 {
 	if(tlbvirt&KZERO)
 		panic("putmmu");
+	if(u){
+		MMU *mp;
+		mp = &(u->mc.mmu[u->mc.next&(NMMU-1)]);
+		mp->pa = tlbphys;
+		mp->va = tlbvirt;
+		mp->pid = u->p->pid;
+		u->mc.next++;
+	}/**/
 	tlbphys |= VTAG(tlbvirt)<<24;
 	UMAP[(tlbvirt&0x003FE000L)>>2] = tlbphys;
 }
@@ -55,6 +83,22 @@ flushmmu(void)
 	*PARAM |= TLBFLUSH_;
 }
 
+void
+flushmmucache(void)
+{
+	if(u == 0)
+		panic("flushmmucache");
+	u->mc.next = 0;
+}
+
+void
+clearmmucache(void)
+{
+	if(u == 0)
+		panic("clearmmucache");
+	memset(&u->mc, 0, sizeof u->mc);
+}
+
 void
 kmapinit(void)
 {
diff --git a/gnot/proc.c b/gnot/proc.c
index 800806ea5ec08adcf33dec33ba27919a502bdc83..e34209871a6f61894f1dd157295a92367d01e226 100644
--- a/gnot/proc.c
+++ b/gnot/proc.c
@@ -621,6 +621,7 @@ kproc(char *name, void (*func)(void *), void *arg)
 	/*
 	 * Save time: only copy u-> data and useful stack
 	 */
+	clearmmucache();
 	memcpy(up, u, sizeof(User));
 	n = USERADDR+BY2PG - (ulong)&lastvar;
 	n = (n+32) & ~(BY2WD-1);	/* be safe & word align */
diff --git a/gnot/sysproc.c b/gnot/sysproc.c
index 6c76c2bca961311f8bc90c24fbea7f2eb18428d7..bad416d4d1ce678a93902582e4cb0c6ed3332d69 100644
--- a/gnot/sysproc.c
+++ b/gnot/sysproc.c
@@ -41,6 +41,7 @@ sysfork(ulong *arg)
 	/*
 	 * Save time: only copy u-> data and useful stack
 	 */
+	clearmmucache();
 	memcpy((void*)upa, u, sizeof(User));
 	n = USERADDR+BY2PG - (ulong)&lastvar;
 	n = (n+32) & ~(BY2WD-1);	/* be safe & word align */
@@ -361,6 +362,7 @@ sysexec(ulong *arg)
 	unlock(o);
 
 	flushmmu();
+	clearmmucache();
 	((Ureg*)UREGADDR)->pc = exec.entry;
 	sp = (ulong*)(USTKTOP - ssize);
 	*--sp = nargs;