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zynq: only tmpmap() while splhi(), remove unneeded coherence() after tmpunmap(), splhi() in l2free()

we have to call tmpmap() with interrupts disabled as the map
is a per cpu and a interrupt can preempt us while we where
commited to use a entry but *before* we wrote it!

tmpunmap() already calls coherence() before flushpg() so it
is not needed after tmpunmap().

splhi() in l2free() isnt needed as l2free() is always called
with interrupts disabled from mmuswitch() and mmurelease().

--- a/sys/src/9/zynq/mmu.c

+++ b/sys/src/9/zynq/mmu.c

@@ -100,13 +100,11 @@

 static void

 l2free(Proc *proc)

 {

-	int s;

 	ulong *t;

 	Page *p, **l;

 	if(proc->l1 == nil || proc->mmuused == nil)

 		return;

-	s = splhi();

 	l = &proc->mmuused;

 	for(p = *l; p != nil; p = p->next){

 		t = proc->l1->va + p->daddr;

@@ -116,7 +114,6 @@

 		*t = 0;

 		l = &p->next;

 	}

-	splx(s);

 	*l = proc->mmufree;

 	proc->mmufree = proc->mmuused;

 	proc->mmuused = 0;

@@ -143,6 +140,7 @@

 	ulong *l2;

 	PTE old;

 	uintptr l2p;

+	int s;

 	if(up->l1 == nil)

 		upallocl1();

@@ -150,11 +148,15 @@

 		pa |= L2CACHED;

 	e = &up->l1->va[L1RX(va)];

 	if((*e & 3) == 0){

-		if(up->mmufree != nil){

-			p = up->mmufree;

+		p = up->mmufree;

+		if(p != nil)

 			up->mmufree = p->next;

-		}else

+		else

 			p = newpage(0, 0, 0);

+		p->daddr = L1RX(va);

+		p->next = up->mmuused;

+		up->mmuused = p;

+		s = splhi();

 		l2p = p->pa;

 		l2 = tmpmap(l2p);

 		memset(l2, 0, BY2PG);

@@ -164,10 +166,8 @@

 		e[2] = e[1] + L2SZ;

 		e[3] = e[2] + L2SZ;

 		coherence();

-		p->daddr = L1RX(va);

-		p->next = up->mmuused;

-		up->mmuused = p;

 	}else{

+		s = splhi();

 		l2p = *e & ~(BY2PG - 1);

 		l2 = tmpmap(l2p);

 	}

@@ -175,7 +175,7 @@

 	old = *e;

 	*e = pa | L2VALID | L2USER | L2LOCAL;

 	tmpunmap(l2);

-	coherence();

+	splx(s);

 	if((old & L2VALID) != 0)

 		flushpg((void *) va);

 	if(pg->cachectl[0] == PG_TXTFLUSH){

@@ -274,8 +274,7 @@

 kmap(Page *page)

 {

 	ulong *e, *v;

-	int i;

-	ulong s;

+	int i, s;

 	if(up == nil)

 		panic("kmap: up=0 pc=%#.8lux", getcallerpc(&page));

@@ -283,23 +282,20 @@

 		upallocl1();

 	if(up->nkmap < 0)

 		panic("kmap %lud %s: nkmap=%d", up->pid, up->text, up->nkmap);

-	s = splhi();

 	up->nkmap++;

 	e = &up->l1->va[L1X(KMAP)];

 	if((*e & 3) == 0){

 		if(up->kmaptable != nil)

 			panic("kmaptable");

-		spllo();

 		up->kmaptable = newpage(0, 0, 0);

-		splhi();

+		s = splhi();

 		v = tmpmap(up->kmaptable->pa);

 		memset(v, 0, BY2PG);

 		v[0] = page->pa | L2KERRW | L2VALID | L2CACHED | L2LOCAL;

 		v[NKMAP] = up->kmaptable->pa | L2KERRW | L2VALID | L2CACHED | L2LOCAL;

 		tmpunmap(v);

-		coherence();

-		*e = up->kmaptable->pa | L1PT;

 		splx(s);

+		*e = up->kmaptable->pa | L1PT;

 		coherence();

 		return (KMap *) KMAP;

 	}

@@ -309,7 +305,6 @@

 	for(i = 0; i < NKMAP; i++)

 		if((e[i] & 3) == 0){

 			e[i] = page->pa | L2KERRW | L2VALID | L2CACHED | L2LOCAL;

-			splx(s);

 			coherence();

 			return (KMap *) (KMAP + i * BY2PG);

 		}

@@ -345,6 +340,8 @@

 	ulong *u, *ub, *ue;

 	void *v;

+	if(islo())

+		panic("tmpmap: islow %#p", getcallerpc(&pa));

 	if(cankaddr(pa))

 		return KADDR(pa);

 	ub = (ulong *) TMAPL2(m->machno);