kernel: fix physical segment handling

ignore physical segments in mcountseg() and mfreeseg(). physical
segments are not backed by user pages, and doing putpage() on
physical segment pages in mfreeseg() is an error.

do now allow physical segemnts to be resized. the segment size
is only checked in segattach() to be within the physical segment!

ignore physical segments in portcountpagerefs() as pagenumber()
does not work on the malloced page structures of a physical segment.

get rid of Physseg.pgalloc() and Physseg.pgfree() indirection as
this was never used and if theres a need to do more efficient
allocation, it should be done in a portable way.

5 files changed, 23 insertions, 34 deletions

diff --git a/sys/src/9/port/fault.c b/sys/src/9/port/fault.c
index d77894641..b6f5e3894 100644
--- a/sys/src/9/port/fault.c
+++ b/sys/src/9/port/fault.c
@@ -200,7 +200,6 @@ fixfault(Segment *s, uintptr addr, int read, int doputmmu)
 	Pte **p, *etp;
 	uintptr soff, mmuphys=0;
 	Page **pg, *old, *new;
-	Page *(*fn)(Segment*, uintptr);
 
 	addr &= ~(BY2PG-1);
 	soff = addr-s->base;
@@ -274,19 +273,13 @@ fixfault(Segment *s, uintptr addr, int read, int doputmmu)
 		break;
 
 	case SG_PHYSICAL:
-		if(*pg == nil) {
-			fn = s->pseg->pgalloc;
-			if(fn)
-				*pg = (*fn)(s, addr);
-			else {
-				new = smalloc(sizeof(Page));
-				new->va = addr;
-				new->pa = s->pseg->pa+(addr-s->base);
-				new->ref = 1;
-				*pg = new;
-			}
+		if(*pg == nil){
+			new = smalloc(sizeof(Page));
+			new->va = addr;
+			new->pa = s->pseg->pa+(addr-s->base);
+			new->ref = 1;
+			*pg = new;
 		}
-
 		if (checkaddr && addr == addr2check)
 			(*checkaddr)(addr, s, *pg);
 		mmuphys = PPN((*pg)->pa) |PTEWRITE|PTEUNCACHED|PTEVALID;
diff --git a/sys/src/9/port/page.c b/sys/src/9/port/page.c
index dcd701267..0061ed658 100644
--- a/sys/src/9/port/page.c
+++ b/sys/src/9/port/page.c
@@ -384,23 +384,11 @@ ptealloc(void)
 void
 freepte(Segment *s, Pte *p)
 {
-	void (*fn)(Page*);
-	Page **pg, **ptop;
+	Page **pg;
 
 	switch(s->type&SG_TYPE) {
 	case SG_PHYSICAL:
-		fn = s->pseg->pgfree;
-		ptop = &p->pages[PTEPERTAB];
-		if(fn != nil) {
-			for(pg = p->pages; pg < ptop; pg++) {
-				if(*pg == nil)
-					continue;
-				(*fn)(*pg);
-				*pg = nil;
-			}
-			break;
-		}
-		for(pg = p->pages; pg < ptop; pg++) {
+		for(pg = p->first; pg <= p->last; pg++) {
 			if(*pg != nil) {
 				if(decref(*pg) == 0)
 					free(*pg);
@@ -409,11 +397,12 @@ freepte(Segment *s, Pte *p)
 		}
 		break;
 	default:
-		for(pg = p->first; pg <= p->last; pg++)
+		for(pg = p->first; pg <= p->last; pg++) {
 			if(*pg != nil) {
 				putpage(*pg);
 				*pg = nil;
 			}
+		}
 	}
 	free(p);
 }
@@ -483,7 +472,7 @@ portcountpagerefs(ulong *ref, int print)
 		p = proctab(i);
 		for(j=0; j<NSEG; j++){
 			s = p->seg[j];
-			if(s)
+			if(s != nil)
 				s->mark = 0;
 		}
 	}
@@ -493,6 +482,8 @@ portcountpagerefs(ulong *ref, int print)
 			s = p->seg[j];
 			if(s == nil || s->mark++)
 				continue;
+			if((s->type&SG_TYPE) == SG_PHYSICAL)
+				continue;
 			ns++;
 			for(k=0; k<s->mapsize; k++){
 				pte = s->map[k];
diff --git a/sys/src/9/port/portdat.h b/sys/src/9/port/portdat.h
index 96e823766..a85dc831b 100644
--- a/sys/src/9/port/portdat.h
+++ b/sys/src/9/port/portdat.h
@@ -359,8 +359,6 @@ struct Physseg
 	char	*name;			/* Attach name */
 	uintptr	pa;			/* Physical address */
 	uintptr	size;			/* Maximum segment size in bytes */
-	Page	*(*pgalloc)(Segment*, uintptr);	/* Allocation if we need it */
-	void	(*pgfree)(Page*);
 };
 
 struct Sema
diff --git a/sys/src/9/port/segment.c b/sys/src/9/port/segment.c
index 5bafd0c36..c64a4efbf 100644
--- a/sys/src/9/port/segment.c
+++ b/sys/src/9/port/segment.c
@@ -11,9 +11,9 @@ int imagereclaim(int);
  * Attachable segment types
  */
 static Physseg physseg[10] = {
-	{ SG_SHARED,	"shared",	0,	SEGMAXSIZE,	0, 	0 },
-	{ SG_BSS,	"memory",	0,	SEGMAXSIZE,	0,	0 },
-	{ 0,		0,		0,	0,		0,	0 },
+	{ SG_SHARED,	"shared",	0,	SEGMAXSIZE	},
+	{ SG_BSS,	"memory",	0,	SEGMAXSIZE	},
+	{ 0,		0,		0,	0		},
 };
 
 static Lock physseglock;
@@ -459,6 +459,9 @@ mcountseg(Segment *s)
 	int i, j;
 	Page *pg;
 
+	if((s->type&SG_TYPE) == SG_PHYSICAL)
+		return 0;
+
 	pages = 0;
 	for(i = 0; i < s->mapsize; i++){
 		if(s->map[i] == nil)
@@ -482,6 +485,9 @@ mfreeseg(Segment *s, uintptr start, int pages)
 	uintptr soff;
 	Page *pg;
 
+	if((s->type&SG_TYPE) == SG_PHYSICAL)
+		return;
+
 	/*
 	 * We want to zero s->map[i]->page[j] and putpage(pg),
 	 * but we have to make sure other processors flush the
diff --git a/sys/src/9/port/sysproc.c b/sys/src/9/port/sysproc.c
index 3cee4f15a..b787a3d6a 100644
--- a/sys/src/9/port/sysproc.c
+++ b/sys/src/9/port/sysproc.c
@@ -745,6 +745,7 @@ syssegbrk(va_list list)
 		case SG_TEXT:
 		case SG_DATA:
 		case SG_STACK:
+		case SG_PHYSICAL:
 			error(Ebadarg);
 		default:
 			return (uintptr)ibrk(va_arg(list, uintptr), i);