Import sources from 2011-03-30 iso image

sys/src/9/port/segment.c

@@ -0,0 +1,799 @@
+#include	"u.h"
+#include	"../port/lib.h"
+#include	"mem.h"
+#include	"dat.h"
+#include	"fns.h"
+#include	"../port/error.h"
+
+static void	imagereclaim(void);
+static void	imagechanreclaim(void);
+
+#include "io.h"
+
+/*
+ * 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 },
+};
+
+static Lock physseglock;
+
+#define NFREECHAN	64
+#define IHASHSIZE	64
+#define ihash(s)	imagealloc.hash[s%IHASHSIZE]
+static struct Imagealloc
+{
+	Lock;
+	Image	*free;
+	Image	*hash[IHASHSIZE];
+	QLock	ireclaim;	/* mutex on reclaiming free images */
+
+	Chan	**freechan;	/* free image channels */
+	int	nfreechan;	/* number of free channels */
+	int	szfreechan;	/* size of freechan array */
+	QLock	fcreclaim;	/* mutex on reclaiming free channels */
+}imagealloc;
+
+Segment* (*_globalsegattach)(Proc*, char*);
+
+void
+initseg(void)
+{
+	Image *i, *ie;
+
+	imagealloc.free = xalloc(conf.nimage*sizeof(Image));
+	if (imagealloc.free == nil)
+		panic("initseg: no memory");
+	ie = &imagealloc.free[conf.nimage-1];
+	for(i = imagealloc.free; i < ie; i++)
+		i->next = i+1;
+	i->next = 0;
+	imagealloc.freechan = malloc(NFREECHAN * sizeof(Chan*));
+	imagealloc.szfreechan = NFREECHAN;
+}
+
+Segment *
+newseg(int type, ulong base, ulong size)
+{
+	Segment *s;
+	int mapsize;
+
+	if(size > (SEGMAPSIZE*PTEPERTAB))
+		error(Enovmem);
+
+	s = smalloc(sizeof(Segment));
+	s->ref = 1;
+	s->type = type;
+	s->base = base;
+	s->top = base+(size*BY2PG);
+	s->size = size;
+	s->sema.prev = &s->sema;
+	s->sema.next = &s->sema;
+
+	mapsize = ROUND(size, PTEPERTAB)/PTEPERTAB;
+	if(mapsize > nelem(s->ssegmap)){
+		mapsize *= 2;
+		if(mapsize > (SEGMAPSIZE*PTEPERTAB))
+			mapsize = (SEGMAPSIZE*PTEPERTAB);
+		s->map = smalloc(mapsize*sizeof(Pte*));
+		s->mapsize = mapsize;
+	}
+	else{
+		s->map = s->ssegmap;
+		s->mapsize = nelem(s->ssegmap);
+	}
+
+	return s;
+}
+
+void
+putseg(Segment *s)
+{
+	Pte **pp, **emap;
+	Image *i;
+
+	if(s == 0)
+		return;
+
+	i = s->image;
+	if(i != 0) {
+		lock(i);
+		lock(s);
+		if(i->s == s && s->ref == 1)
+			i->s = 0;
+		unlock(i);
+	}
+	else
+		lock(s);
+
+	s->ref--;
+	if(s->ref != 0) {
+		unlock(s);
+		return;
+	}
+	unlock(s);
+
+	qlock(&s->lk);
+	if(i)
+		putimage(i);
+
+	emap = &s->map[s->mapsize];
+	for(pp = s->map; pp < emap; pp++)
+		if(*pp)
+			freepte(s, *pp);
+
+	qunlock(&s->lk);
+	if(s->map != s->ssegmap)
+		free(s->map);
+	if(s->profile != 0)
+		free(s->profile);
+	free(s);
+}
+
+void
+relocateseg(Segment *s, ulong offset)
+{
+	Page **pg, *x;
+	Pte *pte, **p, **endpte;
+
+	endpte = &s->map[s->mapsize];
+	for(p = s->map; p < endpte; p++) {
+		if(*p == 0)
+			continue;
+		pte = *p;
+		for(pg = pte->first; pg <= pte->last; pg++) {
+			if(x = *pg)
+				x->va += offset;
+		}
+	}
+}
+
+Segment*
+dupseg(Segment **seg, int segno, int share)
+{
+	int i, size;
+	Pte *pte;
+	Segment *n, *s;
+
+	SET(n);
+	s = seg[segno];
+
+	qlock(&s->lk);
+	if(waserror()){
+		qunlock(&s->lk);
+		nexterror();
+	}
+	switch(s->type&SG_TYPE) {
+	case SG_TEXT:		/* New segment shares pte set */
+	case SG_SHARED:
+	case SG_PHYSICAL:
+		goto sameseg;
+
+	case SG_STACK:
+		n = newseg(s->type, s->base, s->size);
+		break;
+
+	case SG_BSS:		/* Just copy on write */
+		if(share)
+			goto sameseg;
+		n = newseg(s->type, s->base, s->size);
+		break;
+
+	case SG_DATA:		/* Copy on write plus demand load info */
+		if(segno == TSEG){
+			poperror();
+			qunlock(&s->lk);
+			return data2txt(s);
+		}
+
+		if(share)
+			goto sameseg;
+		n = newseg(s->type, s->base, s->size);
+
+		incref(s->image);
+		n->image = s->image;
+		n->fstart = s->fstart;
+		n->flen = s->flen;
+		break;
+	}
+	size = s->mapsize;
+	for(i = 0; i < size; i++)
+		if(pte = s->map[i])
+			n->map[i] = ptecpy(pte);
+
+	n->flushme = s->flushme;
+	if(s->ref > 1)
+		procflushseg(s);
+	poperror();
+	qunlock(&s->lk);
+	return n;
+
+sameseg:
+	incref(s);
+	poperror();
+	qunlock(&s->lk);
+	return s;
+}
+
+void
+segpage(Segment *s, Page *p)
+{
+	Pte **pte;
+	ulong off;
+	Page **pg;
+
+	if(p->va < s->base || p->va >= s->top)
+		panic("segpage");
+
+	off = p->va - s->base;
+	pte = &s->map[off/PTEMAPMEM];
+	if(*pte == 0)
+		*pte = ptealloc();
+
+	pg = &(*pte)->pages[(off&(PTEMAPMEM-1))/BY2PG];
+	*pg = p;
+	if(pg < (*pte)->first)
+		(*pte)->first = pg;
+	if(pg > (*pte)->last)
+		(*pte)->last = pg;
+}
+
+Image*
+attachimage(int type, Chan *c, ulong base, ulong len)
+{
+	Image *i, **l;
+
+	/* reclaim any free channels from reclaimed segments */
+	if(imagealloc.nfreechan)
+		imagechanreclaim();
+
+	lock(&imagealloc);
+
+	/*
+	 * Search the image cache for remains of the text from a previous
+	 * or currently running incarnation
+	 */
+	for(i = ihash(c->qid.path); i; i = i->hash) {
+		if(c->qid.path == i->qid.path) {
+			lock(i);
+			if(eqqid(c->qid, i->qid) &&
+			   eqqid(c->mqid, i->mqid) &&
+			   c->mchan == i->mchan &&
+			   c->type == i->type) {
+				goto found;
+			}
+			unlock(i);
+		}
+	}
+
+	/*
+	 * imagereclaim dumps pages from the free list which are cached by image
+	 * structures. This should free some image structures.
+	 */
+	while(!(i = imagealloc.free)) {
+		unlock(&imagealloc);
+		imagereclaim();
+		sched();
+		lock(&imagealloc);
+	}
+
+	imagealloc.free = i->next;
+
+	lock(i);
+	incref(c);
+	i->c = c;
+	i->type = c->type;
+	i->qid = c->qid;
+	i->mqid = c->mqid;
+	i->mchan = c->mchan;
+	l = &ihash(c->qid.path);
+	i->hash = *l;
+	*l = i;
+found:
+	unlock(&imagealloc);
+
+	if(i->s == 0) {
+		/* Disaster after commit in exec */
+		if(waserror()) {
+			unlock(i);
+			pexit(Enovmem, 1);
+		}
+		i->s = newseg(type, base, len);
+		i->s->image = i;
+		i->ref++;
+		poperror();
+	}
+	else
+		incref(i->s);
+
+	return i;
+}
+
+static struct {
+	int	calls;			/* times imagereclaim was called */
+	int	loops;			/* times the main loop was run */
+	uvlong	ticks;			/* total time in the main loop */
+	uvlong	maxt;			/* longest time in main loop */
+} irstats;
+
+static void
+imagereclaim(void)
+{
+	int n;
+	Page *p;
+	uvlong ticks;
+
+	irstats.calls++;
+	/* Somebody is already cleaning the page cache */
+	if(!canqlock(&imagealloc.ireclaim))
+		return;
+
+	lock(&palloc);
+	ticks = fastticks(nil);
+	n = 0;
+	/*
+	 * All the pages with images backing them are at the
+	 * end of the list (see putpage) so start there and work
+	 * backward.
+	 */
+	for(p = palloc.tail; p && p->image && n<1000; p = p->prev) {
+		if(p->ref == 0 && canlock(p)) {
+			if(p->ref == 0) {
+				n++;
+				uncachepage(p);
+			}
+			unlock(p);
+		}
+	}
+	ticks = fastticks(nil) - ticks;
+	unlock(&palloc);
+	irstats.loops++;
+	irstats.ticks += ticks;
+	if(ticks > irstats.maxt)
+		irstats.maxt = ticks;
+	//print("T%llud+", ticks);
+	qunlock(&imagealloc.ireclaim);
+}
+
+/*
+ *  since close can block, this has to be called outside of
+ *  spin locks.
+ */
+static void
+imagechanreclaim(void)
+{
+	Chan *c;
+
+	/* Somebody is already cleaning the image chans */
+	if(!canqlock(&imagealloc.fcreclaim))
+		return;
+
+	/*
+	 * We don't have to recheck that nfreechan > 0 after we
+	 * acquire the lock, because we're the only ones who decrement 
+	 * it (the other lock contender increments it), and there's only
+	 * one of us thanks to the qlock above.
+	 */
+	while(imagealloc.nfreechan > 0){
+		lock(&imagealloc);
+		imagealloc.nfreechan--;
+		c = imagealloc.freechan[imagealloc.nfreechan];
+		unlock(&imagealloc);
+		cclose(c);
+	}
+
+	qunlock(&imagealloc.fcreclaim);
+}
+
+void
+putimage(Image *i)
+{
+	Chan *c, **cp;
+	Image *f, **l;
+
+	if(i->notext)
+		return;
+
+	lock(i);
+	if(--i->ref == 0) {
+		l = &ihash(i->qid.path);
+		mkqid(&i->qid, ~0, ~0, QTFILE);
+		unlock(i);
+		c = i->c;
+
+		lock(&imagealloc);
+		for(f = *l; f; f = f->hash) {
+			if(f == i) {
+				*l = i->hash;
+				break;
+			}
+			l = &f->hash;
+		}
+
+		i->next = imagealloc.free;
+		imagealloc.free = i;
+
+		/* defer freeing channel till we're out of spin lock's */
+		if(imagealloc.nfreechan == imagealloc.szfreechan){
+			imagealloc.szfreechan += NFREECHAN;
+			cp = malloc(imagealloc.szfreechan*sizeof(Chan*));
+			if(cp == nil)
+				panic("putimage");
+			memmove(cp, imagealloc.freechan, imagealloc.nfreechan*sizeof(Chan*));
+			free(imagealloc.freechan);
+			imagealloc.freechan = cp;
+		}
+		imagealloc.freechan[imagealloc.nfreechan++] = c;
+		unlock(&imagealloc);
+
+		return;
+	}
+	unlock(i);
+}
+
+long
+ibrk(ulong addr, int seg)
+{
+	Segment *s, *ns;
+	ulong newtop, newsize;
+	int i, mapsize;
+	Pte **map;
+
+	s = up->seg[seg];
+	if(s == 0)
+		error(Ebadarg);
+
+	if(addr == 0)
+		return s->base;
+
+	qlock(&s->lk);
+
+	/* We may start with the bss overlapping the data */
+	if(addr < s->base) {
+		if(seg != BSEG || up->seg[DSEG] == 0 || addr < up->seg[DSEG]->base) {
+			qunlock(&s->lk);
+			error(Enovmem);
+		}
+		addr = s->base;
+	}
+
+	newtop = PGROUND(addr);
+	newsize = (newtop-s->base)/BY2PG;
+	if(newtop < s->top) {
+		/*
+		 * do not shrink a segment shared with other procs, as the
+		 * to-be-freed address space may have been passed to the kernel
+		 * already by another proc and is past the validaddr stage.
+		 */
+		if(s->ref > 1){
+			qunlock(&s->lk);
+			error(Einuse);
+		}
+		mfreeseg(s, newtop, (s->top-newtop)/BY2PG);
+		s->top = newtop;
+		s->size = newsize;
+		qunlock(&s->lk);
+		flushmmu();
+		return 0;
+	}
+
+	for(i = 0; i < NSEG; i++) {
+		ns = up->seg[i];
+		if(ns == 0 || ns == s)
+			continue;
+		if(newtop >= ns->base && newtop < ns->top) {
+			qunlock(&s->lk);
+			error(Esoverlap);
+		}
+	}
+
+	if(newsize > (SEGMAPSIZE*PTEPERTAB)) {
+		qunlock(&s->lk);
+		error(Enovmem);
+	}
+	mapsize = ROUND(newsize, PTEPERTAB)/PTEPERTAB;
+	if(mapsize > s->mapsize){
+		map = smalloc(mapsize*sizeof(Pte*));
+		memmove(map, s->map, s->mapsize*sizeof(Pte*));
+		if(s->map != s->ssegmap)
+			free(s->map);
+		s->map = map;
+		s->mapsize = mapsize;
+	}
+
+	s->top = newtop;
+	s->size = newsize;
+	qunlock(&s->lk);
+	return 0;
+}
+
+/*
+ *  called with s->lk locked
+ */
+void
+mfreeseg(Segment *s, ulong start, int pages)
+{
+	int i, j, size;
+	ulong soff;
+	Page *pg;
+	Page *list;
+
+	soff = start-s->base;
+	j = (soff&(PTEMAPMEM-1))/BY2PG;
+
+	size = s->mapsize;
+	list = nil;
+	for(i = soff/PTEMAPMEM; i < size; i++) {
+		if(pages <= 0)
+			break;
+		if(s->map[i] == 0) {
+			pages -= PTEPERTAB-j;
+			j = 0;
+			continue;
+		}
+		while(j < PTEPERTAB) {
+			pg = s->map[i]->pages[j];
+			/*
+			 * We want to zero s->map[i]->page[j] and putpage(pg),
+			 * but we have to make sure other processors flush the
+			 * entry from their TLBs before the page is freed.
+			 * We construct a list of the pages to be freed, zero
+			 * the entries, then (below) call procflushseg, and call
+			 * putpage on the whole list.
+			 *
+			 * Swapped-out pages don't appear in TLBs, so it's okay
+			 * to putswap those pages before procflushseg.
+			 */
+			if(pg){
+				if(onswap(pg))
+					putswap(pg);
+				else{
+					pg->next = list;
+					list = pg;
+				}
+				s->map[i]->pages[j] = 0;
+			}
+			if(--pages == 0)
+				goto out;
+			j++;
+		}
+		j = 0;
+	}
+out:
+	/* flush this seg in all other processes */
+	if(s->ref > 1)
+		procflushseg(s);
+
+	/* free the pages */
+	for(pg = list; pg != nil; pg = list){
+		list = list->next;
+		putpage(pg);
+	}
+}
+
+Segment*
+isoverlap(Proc *p, ulong va, int len)
+{
+	int i;
+	Segment *ns;
+	ulong newtop;
+
+	newtop = va+len;
+	for(i = 0; i < NSEG; i++) {
+		ns = p->seg[i];
+		if(ns == 0)
+			continue;
+		if((newtop > ns->base && newtop <= ns->top) ||
+		   (va >= ns->base && va < ns->top))
+			return ns;
+	}
+	return nil;
+}
+
+int
+addphysseg(Physseg* new)
+{
+	Physseg *ps;
+
+	/*
+	 * Check not already entered and there is room
+	 * for a new entry and the terminating null entry.
+	 */
+	lock(&physseglock);
+	for(ps = physseg; ps->name; ps++){
+		if(strcmp(ps->name, new->name) == 0){
+			unlock(&physseglock);
+			return -1;
+		}
+	}
+	if(ps-physseg >= nelem(physseg)-2){
+		unlock(&physseglock);
+		return -1;
+	}
+
+	*ps = *new;
+	unlock(&physseglock);
+
+	return 0;
+}
+
+int
+isphysseg(char *name)
+{
+	Physseg *ps;
+	int rv = 0;
+
+	lock(&physseglock);
+	for(ps = physseg; ps->name; ps++){
+		if(strcmp(ps->name, name) == 0){
+			rv = 1;
+			break;
+		}
+	}
+	unlock(&physseglock);
+	return rv;
+}
+
+ulong
+segattach(Proc *p, ulong attr, char *name, ulong va, ulong len)
+{
+	int sno;
+	Segment *s, *os;
+	Physseg *ps;
+
+	if(va != 0 && va >= USTKTOP)
+		error(Ebadarg);
+
+	validaddr((ulong)name, 1, 0);
+	vmemchr(name, 0, ~0);
+
+	for(sno = 0; sno < NSEG; sno++)
+		if(p->seg[sno] == nil && sno != ESEG)
+			break;
+
+	if(sno == NSEG)
+		error(Enovmem);
+
+	/*
+	 *  first look for a global segment with the
+	 *  same name
+	 */
+	if(_globalsegattach != nil){
+		s = (*_globalsegattach)(p, name);
+		if(s != nil){
+			p->seg[sno] = s;
+			return s->base;
+		}
+	}
+
+	len = PGROUND(len);
+	if(len == 0)
+		error(Ebadarg);
+
+	/*
+	 * Find a hole in the address space.
+	 * Starting at the lowest possible stack address - len,
+	 * check for an overlapping segment, and repeat at the
+	 * base of that segment - len until either a hole is found
+	 * or the address space is exhausted.  Ensure that we don't
+	 * map the zero page.
+	 */
+	if(va == 0) {
+		for (os = p->seg[SSEG]; os != nil; os = isoverlap(p, va, len)) {
+			va = os->base;
+			if(len >= va)
+				error(Enovmem);
+			va -= len;
+		}
+		va &= ~(BY2PG-1);
+	} else {
+		va &= ~(BY2PG-1);
+		if(va == 0 || va >= USTKTOP)
+			error(Ebadarg);
+	}
+
+	if(isoverlap(p, va, len) != nil)
+		error(Esoverlap);
+
+	for(ps = physseg; ps->name; ps++)
+		if(strcmp(name, ps->name) == 0)
+			goto found;
+
+	error(Ebadarg);
+found:
+	if(len > ps->size)
+		error(Enovmem);
+
+	attr &= ~SG_TYPE;		/* Turn off what is not allowed */
+	attr |= ps->attr;		/* Copy in defaults */
+
+	s = newseg(attr, va, len/BY2PG);
+	s->pseg = ps;
+	p->seg[sno] = s;
+
+	return va;
+}
+
+void
+pteflush(Pte *pte, int s, int e)
+{
+	int i;
+	Page *p;
+
+	for(i = s; i < e; i++) {
+		p = pte->pages[i];
+		if(pagedout(p) == 0)
+			memset(p->cachectl, PG_TXTFLUSH, sizeof(p->cachectl));
+	}
+}
+
+long
+syssegflush(ulong *arg)
+{
+	Segment *s;
+	ulong addr, l;
+	Pte *pte;
+	int chunk, ps, pe, len;
+
+	addr = arg[0];
+	len = arg[1];
+
+	while(len > 0) {
+		s = seg(up, addr, 1);
+		if(s == 0)
+			error(Ebadarg);
+
+		s->flushme = 1;
+	more:
+		l = len;
+		if(addr+l > s->top)
+			l = s->top - addr;
+
+		ps = addr-s->base;
+		pte = s->map[ps/PTEMAPMEM];
+		ps &= PTEMAPMEM-1;
+		pe = PTEMAPMEM;
+		if(pe-ps > l){
+			pe = ps + l;
+			pe = (pe+BY2PG-1)&~(BY2PG-1);
+		}
+		if(pe == ps) {
+			qunlock(&s->lk);
+			error(Ebadarg);
+		}
+
+		if(pte)
+			pteflush(pte, ps/BY2PG, pe/BY2PG);
+
+		chunk = pe-ps;
+		len -= chunk;
+		addr += chunk;
+
+		if(len > 0 && addr < s->top)
+			goto more;
+
+		qunlock(&s->lk);
+	}
+	flushmmu();
+	return 0;
+}
+
+void
+segclock(ulong pc)
+{
+	Segment *s;
+
+	s = up->seg[TSEG];
+	if(s == 0 || s->profile == 0)
+		return;
+
+	s->profile[0] += TK2MS(1);
+	if(pc >= s->base && pc < s->top) {
+		pc -= s->base;
+		s->profile[pc>>LRESPROF] += TK2MS(1);
+	}
+}
+