Getting rid of machp() accesses with interrupts enabled, most of them beningn, some of them dubious.

Moving page size stuff to sys got rid of plenty of them.
A pass at stack traces, made sure the frame pointer chain terminates in main and before crossing to user.

Change-Id: Icae8eabd0aecf992c714a36eea5c4fee9817a169

sys/src/9/k10/archk10.c

@@ -295,10 +295,10 @@ archmmu(void)
 	 */
 	assert(PGSZ == 4*KiB);
 
-	machp()->pgszlg2[0] = 12;
-	machp()->pgszmask[0] = (1<<12)-1;
-	machp()->pgsz[0] = 1<<12;
-	machp()->npgsz = 1;
+	sys->pgszlg2[0] = 12;
+	sys->pgszmask[0] = (1<<12)-1;
+	sys->pgsz[0] = 1<<12;
+	sys->npgsz = 1;
 	if(machp()->ncpuinfos == 0 && cpuidinit() == 0)
 		return 1;
 
@@ -308,22 +308,22 @@ archmmu(void)
 	 */
 	if(!(machp()->cpuinfo[1][3] & 0x00000008))
 		return 1;
-	machp()->pgszlg2[1] = 21;
-	machp()->pgszmask[1] = (1<<21)-1;
-	machp()->pgsz[1] = 1<<21;
-	machp()->npgsz = 2;
+	sys->pgszlg2[1] = 21;
+	sys->pgszmask[1] = (1<<21)-1;
+	sys->pgsz[1] = 1<<21;
+	sys->npgsz = 2;
 
 	/*
 	 * Check the Page1GB bit in function 0x80000001 DX for 1*GiB support.
 	 */
 	if(cpuidinfo(0x80000001, 0, info) && (info[3] & 0x04000000)){
-		machp()->pgszlg2[2] = 30;
-		machp()->pgszmask[2] = (1<<30)-1;
-		machp()->pgsz[2] = 1<<30;
-		machp()->npgsz = 3;
+		sys->pgszlg2[2] = 30;
+		sys->pgszmask[2] = (1<<30)-1;
+		sys->pgsz[2] = 1<<30;
+		sys->npgsz = 3;
 	}
 
-	return machp()->npgsz;
+	return sys->npgsz;
 }
 
 static int
@@ -404,7 +404,7 @@ microdelay(int microsecs)
 	uint64_t r, t;
 
 	r = rdtsc();
-	for(t = r + machp()->cpumhz*microsecs; r < t; r = rdtsc())
+	for(t = r + (sys->cyclefreq*microsecs)/1000000ull; r < t; r = rdtsc())
 		;
 }
 
@@ -414,6 +414,6 @@ millidelay(int millisecs)
 	uint64_t r, t;
 
 	r = rdtsc();
-	for(t = r + machp()->cpumhz*1000ull*millisecs; r < t; r = rdtsc())
+	for(t = r + (sys->cyclefreq*millisecs)/1000ull; r < t; r = rdtsc())
 		;
 }

sys/src/9/k10/asm.c

@@ -326,7 +326,7 @@ asmmeminit(void)
 	int cx;
 #endif /* ConfCrap */
 
-	assert(!((sys->vmunmapped|sys->vmend) & machp()->pgszmask[1]));
+	assert(!((sys->vmunmapped|sys->vmend) & sys->pgszmask[1]));
 
 	if((pa = mmuphysaddr(sys->vmunused)) == ~0)
 		panic("asmmeminit 1");
@@ -362,11 +362,11 @@ asmmeminit(void)
 		hi = assem->addr+assem->size;
 		/* Convert a range into pages */
 		for(mem = lo; mem < hi; mem = nextmem){
-			nextmem = (mem + PGLSZ(0)) & ~machp()->pgszmask[0];
+			nextmem = (mem + PGLSZ(0)) & ~sys->pgszmask[0];
 
 			/* Try large pages first */
-			for(i = machp()->npgsz - 1; i >= 0; i--){
-				if((mem & machp()->pgszmask[i]) != 0)
+			for(i = sys->npgsz - 1; i >= 0; i--){
+				if((mem & sys->pgszmask[i]) != 0)
 					continue;
 				if(mem + PGLSZ(i) > hi)
 					continue;

sys/src/9/k10/dat.h

@@ -33,6 +33,7 @@ typedef struct PNOTIFY PNOTIFY;
 typedef uint64_t PTE;
 typedef struct Proc Proc;
 typedef struct Sys Sys;
+typedef struct Stackframe Stackframe;
 typedef uint64_t uintmem;				/* Physical address (hideous) */
 typedef struct Ureg Ureg;
 typedef struct Vctl Vctl;
@@ -174,11 +175,6 @@ struct MMMU
 	Page*	pml4;			/* pml4 for this processor */
 	PTE*	pmap;			/* unused as of yet */
 
-	uint	pgszlg2[NPGSZ];		/* per Mach or per Sys? */
-	uint	pgszmask[NPGSZ];
-	uint	pgsz[NPGSZ];
-	int	npgsz;
-
 	Page	pml4kludge;		/* NIX KLUDGE: we need a page */
 };
 
@@ -316,6 +312,12 @@ struct Mach
 	NIX;
 };
 
+struct Stackframe
+{
+	Stackframe *next;
+	uintptr_t pc;
+};
+
 /*
  * This is the low memory map, between 0x100000 and 0x110000.
  * It is located there to allow fundamental datastructures to be
@@ -368,10 +370,17 @@ struct Sys {
 		unsigned char	ptrpage[4*KiB];
 	};
 
+	uint64_t	cyclefreq;		/* Frequency of user readable cycle counter (mach 0) */
+
+	uint	pgszlg2[NPGSZ];		/* per Mach or per Sys? */
+	uint	pgszmask[NPGSZ];	/* Per sys -aki */
+	uint	pgsz[NPGSZ];
+	int	npgsz;
+
 	unsigned char	_57344_[2][4*KiB];		/* unused */
 };
 
-extern Sys* sys;
+extern Sys *sys;
 
 /*
  * KMap

sys/src/9/k10/devarch.c

@@ -613,7 +613,7 @@ delay(int millisecs)
 	if(millisecs <= 0)
 		millisecs = 1;
 	r = rdtsc();
-	for(t = r + machp()->cpumhz*1000ull*millisecs; r < t; r = rdtsc())
+	for(t = r + (sys->cyclefreq*millisecs)/1000ull; r < t; r = rdtsc())
 		;
 }
 

sys/src/9/k10/entry.S

@@ -349,6 +349,7 @@ _zap0done:
 	movq	%rbx, %rsi
 	movq	%rax, %rax
 	movq	%rax, %rdi				/* multiboot magic */
+	xorq	%rbp, %rbp			/* stack trace ends here */
 	CALL	main
 
 .globl ndnr
@@ -588,6 +589,7 @@ _apstart64v:
 	movq	%rax, %rsi			/* Mach * */
 
 	MOVQ	8(%rsi), %rAX			/* m->splpc */
+	xorq	%rbp, %rbp			/* stack trace ends here */
 	CALL	*%raX				/* CALL squidboy(SB) */
 
 

sys/src/9/k10/fns.h

@@ -148,6 +148,8 @@ uint64_t	spllo(void);
 void	splx(uint64_t);
 void	splxpc(uint64_t);
 void	kstackok(void); /* panic if kstack guards garbaged, works with and without externup */
+Stackframe	*stackframe(void); /* l64v.S */
+void	stacksnippet(void);
 void	stopac(void);
 void	syncclock(void);
 void	syscall(int scallnr, Ureg *ureg);

sys/src/9/k10/l64idt.S

@@ -106,6 +106,9 @@ _intrnested:
 
 	MOVQ	%rsp, %rdi // it's ok, we saved %rdi.
 	xorq	%rax, %rax
+	/* if we came from user, stack traces end here */
+	CMPW	$SSEL(SiCS, SsTIGDT|SsRPL0), 144(%rsp)
+	cmovneq	%rax, %rbp
 	pushq	%rax
 	popfq				/* clear all flags. is there something else we should clear too? */
 	CALL	_trap

sys/src/9/k10/l64v.S

@@ -282,6 +282,15 @@ sfence:
 	SFENCE
 	RET
 
+/*
+ *	x86 convention is to use %rbp as the frame pointer,
+ *	so we just return that register
+ */
+.global stackframe
+stackframe:
+	movq	%rbp, %rax
+	retq
+
 /*
  *	disable interrupts,
  *	return old flags for splx()

sys/src/9/k10/l64vsyscall.S

@@ -75,7 +75,8 @@ syscallentry:
 	movq	%rax, %rdi
 	xorq	%rax, %rax
 	pushq	%rax
-	popfq				/* clear all flags. is there something else we should clear too? */
+	popfq			/* clear all flags. is there something else we should clear too? */
+	movq	$0, %rbp	/* stack traces end here */
 	CALL	syscall
 
 	.globl	syscallreturn

sys/src/9/k10/main.c

@@ -55,6 +55,27 @@ static int vflag = 1;
 
 int nosmp = 1;
 
+
+/*
+ *	this may need improvement, but right now it's just for
+ *	pretty printing below, so it doesn't need to be accurate
+ */
+static int
+ktextaddr(uintptr_t pc)
+{
+	return (pc & 0xfffffffff0000000) == 0xfffffffff0000000;
+}
+
+void
+stacksnippet(void)
+{
+	Stackframe *stkfr;
+	print(" stack:");
+	for(stkfr = stackframe(); stkfr != nil; stkfr = stkfr->next)
+		print(" %c:%p", ktextaddr(stkfr->pc) ? 'k' : '?', ktextaddr(stkfr->pc) ? (stkfr->pc & 0xfffffff) : stkfr->pc);
+	print("\n");
+}
+
 void
 machp_bad(void)
 {
@@ -74,7 +95,8 @@ machp_bad(void)
 		return;
 	}
 	trace[i] = badpc;
-	print("machp access spllo pc %p\n", badpc);
+	print("machp access spllo,");
+	stacksnippet();
 }
 
 void
@@ -492,6 +514,7 @@ main(uint32_t mbmagic, uint32_t mbaddress)
 	 */
 	mach->cpuhz = 2000000000ll;
 	mach->cpumhz = 2000;
+	sys->cyclefreq = mach->cpuhz;
 
 	cgainit();
 	i8250console("0");
@@ -516,6 +539,7 @@ main(uint32_t mbmagic, uint32_t mbaddress)
 	if((hz = archhz()) != 0ll){
 		mach->cpuhz = hz;
 		mach->cyclefreq = hz;
+		sys->cyclefreq = hz;
 		mach->cpumhz = hz/1000000ll;
 	}
 	//iprint("archhz returns 0x%lld\n", hz);

sys/src/9/k10/mmu.c

@@ -402,7 +402,7 @@ mmuput(uintptr_t va, Page *pg, uint attr)
 		print("%s", buf);
 	}
 	assert(pg->pgszi >= 0);
-	pgsz = machp()->pgsz[pg->pgszi];
+	pgsz = sys->pgsz[pg->pgszi];
 	if(pa & (pgsz-1))
 		panic("mmuput: pa offset non zero: %#ullx\n", pa);
 	pa |= pteflags(attr);
@@ -789,7 +789,7 @@ mmuinit(void)
 	uint64_t o, pa, r, sz;
 
 	archmmu();
-	DBG("mach%d: %#p pml4 %#p npgsz %d\n", machp()->machno, machp(), machp()->pml4, machp()->npgsz);
+	DBG("mach%d: %#p pml4 %#p npgsz %d\n", machp()->machno, machp(), machp()->pml4, sys->npgsz);
 
 	if(machp()->machno != 0){
 		/* NIX: KLUDGE: Has to go when each mach is using

sys/src/9/k10/trap.c

@@ -413,14 +413,21 @@ trap(Ureg* ureg)
 			if(up)
 				up->nqtrap++;
 
-		if(ctl->isr)
+		if(ctl->isr){
 			ctl->isr(vno);
+			if(islo())print("trap %d: isr %p enabled interrupts\n", vno, ctl->isr);
+		}
 		for(v = ctl; v != nil; v = v->next){
-			if(v->f)
+			if(v->f){
 				v->f(ureg, v->a);
+				if(islo())print("trap %d: ctlf %p enabled interrupts\n", vno, v->f);
+			}
 		}
-		if(ctl->eoi)
+		if(ctl->eoi){
 			ctl->eoi(vno);
+			if(islo())print("trap %d: eoi %p enabled interrupts\n", vno, ctl->eoi);
+		}
+
 		intrtime(vno);
 		if(ctl->isintr){
 			if(ctl->irq == IrqCLOCK || ctl->irq == IrqTIMER)

sys/src/9/port/devproc.c

@@ -1823,7 +1823,7 @@ procctlmemio(Proc *p, uintptr_t offset, int n, void *va, int read)
 	pte = s->map[soff/PTEMAPMEM];
 	if(pte == 0)
 		panic("procctlmemio");
-	pgsz = machp()->pgsz[s->pgszi];
+	pgsz = sys->pgsz[s->pgszi];
 	pg = pte->pages[(soff&(PTEMAPMEM-1))/pgsz];
 	if(pagedout(pg))
 		panic("procctlmemio1");

sys/src/9/port/fault.c

@@ -47,9 +47,9 @@ fault(uintptr_t addr, uintptr_t pc, int ftype)
 
 	sps = up->psstate;
 	up->psstate = "Fault";
-	spllo();
 
 	machp()->pfault++;
+	spllo();
 	for(i = 0;; i++) {
 		s = seg(up, addr, 1);	 /* leaves s->lk qlocked if seg != nil */
 		//print("%s fault seg for %p is %p base %p top %p\n", faulttypes[ftype], addr, s, s->base, s->top);
@@ -76,7 +76,7 @@ fault(uintptr_t addr, uintptr_t pc, int ftype)
 		if(i > 0 && (i%1000) == 0)
 			print("fault: tried %d times\n", i);
 	}
-
+	splhi();
 	up->psstate = sps;
 	return 0;
 fail:
@@ -94,6 +94,7 @@ fail:
 			faulttypes[ftype],
 			up->pid, addr, pc);
 	}
+	splhi();
 	up->psstate = sps;
 	return -1;
 }
@@ -130,7 +131,7 @@ fixfault(Segment *s, uintptr_t addr, int ftype, int dommuput, int color)
 	Page **pg, *lkp, *new;
 	Page *(*fn)(Segment*, uintptr_t);
 
-	pgsz = machp()->pgsz[s->pgszi];
+	pgsz = sys->pgsz[s->pgszi];
 	addr &= ~(pgsz-1);
 	soff = addr-s->base;
 	p = &s->map[soff/PTEMAPMEM];
@@ -304,7 +305,7 @@ pio(Segment *s, uintptr_t addr, uint32_t soff, Page **p, int color)
 	loadrec = *p;
 	daddr = ask = 0;
 	c = nil;
-	pgsz = machp()->pgsz[s->pgszi];
+	pgsz = sys->pgsz[s->pgszi];
 	if(loadrec == nil) {	/* from a text/data image */
 		daddr = s->ldseg.pg0fileoff + soff;
 		doff = s->ldseg.pg0off;

sys/src/9/port/page.c

@@ -43,11 +43,11 @@ seprintpagestats(char *s, char *e)
 	int i;
 
 	lock(&pga);
-	for(i = 0; i < machp()->npgsz; i++)
-		if(machp()->pgsz[i] != 0)
+	for(i = 0; i < sys->npgsz; i++)
+		if(sys->pgsz[i] != 0)
 			s = seprint(s, e, "%uld/%d %dK user pages avail\n",
 				pga.pgsza[i].freecount,
-				pga.pgsza[i].npages.ref, machp()->pgsz[i]/KiB);
+				pga.pgsza[i].npages.ref, sys->pgsz[i]/KiB);
 	unlock(&pga);
 	return s;
 }
@@ -64,23 +64,23 @@ pageinit(void)
 	Page *pg;
 
 	pga.userinit = 1;
-	DBG("pageinit: npgsz = %d\n", machp()->npgsz);
+	DBG("pageinit: npgsz = %d\n", sys->npgsz);
 	/*
 	 * Don't pre-allocate 4K pages, we are not using them anymore.
 	 */
-	for(si = 1; si < machp()->npgsz; si++){
+	for(si = 1; si < sys->npgsz; si++){
 		for(i = 0; i < Nstartpgs; i++){
 			if(si < 2)
 				color = -1;
 			else
 				color = i;
-			pg = pgalloc(machp()->pgsz[si], color);
+			pg = pgalloc(sys->pgsz[si], color);
 			if(pg == nil){
 				DBG("pageinit: pgalloc failed. breaking.\n");
 				break;	/* don't consume more memory */
 			}
 			DBG("pageinit: alloced pa %#P sz %#ux color %d\n",
-				pg->pa, machp()->pgsz[si], pg->color);
+				pg->pa, sys->pgsz[si], pg->color);
 			lock(&pga);
 			pg->ref = 0;
 			pagechainhead(pg);
@@ -96,8 +96,8 @@ getpgszi(usize size)
 {
 	int si;
 
-	for(si = 0; si < machp()->npgsz; si++)
-		if(size == machp()->pgsz[si])
+	for(si = 0; si < sys->npgsz; si++)
+		if(size == sys->pgsz[si])
 			return si;
 	print("getpgszi: size %#ulx not found\n", size);
 	return -1;
@@ -130,7 +130,7 @@ void
 pgfree(Page* pg)
 {
 	decref(&pga.pgsza[pg->pgszi].npages);
-	physfree(pg->pa, machp()->pgsz[pg->pgszi]);
+	physfree(pg->pa, sys->pgsz[pg->pgszi]);
 	free(pg);
 }
 
@@ -313,13 +313,13 @@ if (VA(k) == 0xfffffe007d800000ULL) trip++;
 		int i;
 		uint64_t *v = (void *)VA(k);
 		if (1)
-		for(i = 0; i < machp()->pgsz[p->pgszi]/sizeof(*v); i++)
+		for(i = 0; i < sys->pgsz[p->pgszi]/sizeof(*v); i++)
 			v[i] = 0;
 //if (trip) die("trip");
 		kunmap(k);
 	}
 	DBG("newpage: va %#p pa %#ullx pgsz %#ux color %d\n",
-		p->va, p->pa, machp()->pgsz[p->pgszi], p->color);
+		p->va, p->pa, sys->pgsz[p->pgszi], p->color);
 
 	return p;
 }
@@ -498,7 +498,7 @@ copypage(Page *f, Page *t)
 		panic("copypage");
 	ks = kmap(f);
 	kd = kmap(t);
-	memmove((void*)VA(kd), (void*)VA(ks), machp()->pgsz[t->pgszi]);
+	memmove((void*)VA(kd), (void*)VA(ks), sys->pgsz[t->pgszi]);
 	kunmap(ks);
 	kunmap(kd);
 }

sys/src/9/port/pager.c

@@ -200,11 +200,11 @@ freepages(int si, int once)
 	Pgsza *pa;
 	Page *p;
 
-	for(; si < machp()->npgsz; si++){
+	for(; si < sys->npgsz; si++){
 		pa = &pga.pgsza[si];
 		if(pa->freecount > 0){
 			DBG("kickpager() up %#p: releasing %udK pages\n",
-				up, machp()->pgsz[si]/KiB);
+				up, sys->pgsz[si]/KiB);
 			lock(&pga);
 			if(pa->freecount == 0){
 				unlock(&pga);
@@ -227,7 +227,7 @@ tryalloc(int pgszi, int color)
 {
 	Page *p;
 
-	p = pgalloc(machp()->pgsz[pgszi], color);
+	p = pgalloc(sys->pgsz[pgszi], color);
 	if(p != nil){
 		lock(&pga);
 		pagechainhead(p);
@@ -288,7 +288,7 @@ kickpager(int pgszi, int color)
 	/*
 	 * If pgszi is <= text page size, try releasing text pages.
 	 */
-	if(machp()->pgsz[pgszi] <= 2*MiB){
+	if(sys->pgsz[pgszi] <= 2*MiB){
 		pstats.ntext++;
 		DBG("kickpager() up %#p: reclaiming text pages\n", up);
 		pageouttext(pgszi, color);

sys/src/9/port/proc.c

@@ -181,7 +181,7 @@ sched(void)
 	Proc *up = externup();
 	Proc *p;
 
-	if(machp()->ilockdepth)
+	if(!islo() && machp()->ilockdepth)
 		panic("cpu%d: ilockdepth %d, last lock %#p at %#p, sched called from %#p",
 			machp()->machno,
 			machp()->ilockdepth,
@@ -798,7 +798,7 @@ loop:
 	 *  or one that hasn't moved in a while (load balancing).  Every
 	 *  time around the loop affinity goes down.
 	 */
-	spllo();
+	splhi();
 	for(i = 0;; i++){
 		/*
 		 *  find the highest priority target process that this
@@ -815,6 +815,7 @@ loop:
 
 		/* waste time or halt the CPU */
 		idlehands();
+		splhi();
 		/* remember how much time we're here */
 		now = perfticks();
 		machp()->perf.inidle += now-start;
@@ -822,7 +823,6 @@ loop:
 	}
 
 found:
-	splhi();
 	p = dequeueproc(&run, rq, p);
 	if(p == nil)
 		goto loop;

sys/src/9/port/qlock.c

@@ -36,8 +36,12 @@ qlock(QLock *q)
 	uint64_t t0;
 
 	cycles(&t0);
-	if(machp()->ilockdepth != 0)
-		print("qlock: %#p: ilockdepth %d", getcallerpc(&q), machp()->ilockdepth);
+
+	if(!islo() && machp()->ilockdepth != 0){
+		print("qlock with ilockdepth %d,", machp()->ilockdepth);
+		stacksnippet();
+	}
+
 	if(up != nil && up->nlocks)
 		print("qlock: %#p: nlocks %d", getcallerpc(&q), up->nlocks);
 

sys/src/9/port/segment.c

@@ -32,7 +32,7 @@ segppn(Segment *s, uintmem pa)
 {
 	uintmem pgsz;
 
-	pgsz = machp()->pgsz[s->pgszi];
+	pgsz = sys->pgsz[s->pgszi];
 	pa &= ~(pgsz-1);
 	return pa;
 }
@@ -278,7 +278,7 @@ segpage(Segment *s, Page *p)
 	pte = &s->map[soff/PTEMAPMEM];
 	if(*pte == 0)
 		*pte = ptealloc(s);
-	pgsz = machp()->pgsz[s->pgszi];
+	pgsz = sys->pgsz[s->pgszi];
 	pg = &(*pte)->pages[(soff&(PTEMAPMEM-1))/pgsz];
 	*pg = p;
 	if(pg < (*pte)->first)
@@ -299,7 +299,7 @@ mfreeseg(Segment *s, uintptr_t start, int pages)
 	Page *pg;
 	Page *list;
 
-	pgsz = machp()->pgsz[s->pgszi];
+	pgsz = sys->pgsz[s->pgszi];
 	soff = start-s->base;
 	j = (soff&(PTEMAPMEM-1))/pgsz;
 
@@ -404,7 +404,7 @@ prepageseg(int i)
 	if(s == nil)
 		return;
 	DBG("prepage: base %#p top %#p\n", s->base, s->top);
-	pgsz = machp()->pgsz[s->pgszi];
+	pgsz = sys->pgsz[s->pgszi];
 	for(addr = s->base; addr < s->top; addr += pgsz)
 		fault(addr, -1, (s->type & SG_WRITE) ? FT_WRITE : FT_READ);
 }

sys/src/9/port/sysproc.c

@@ -386,10 +386,12 @@ execac(Ar0* ar0, int flags, char *ufile, char **argv)
 		error(Ebadexec);
 	}
 
+	/* TODO(aki): not sure I see the point
 	if(up->ac != nil && up->ac != machp())
 		up->color = corecolor(up->ac->machno);
 	else
 		up->color = corecolor(machp()->machno);
+	*/
 
 	/*
 	 * The new stack is temporarily mapped elsewhere.
@@ -433,7 +435,7 @@ execac(Ar0* ar0, int flags, char *ufile, char **argv)
 	 * First, the top-of-stack structure.
 	 */
 	tos = (Tos*)stack;
-	tos->cyclefreq = machp()->cyclefreq;
+	tos->cyclefreq = sys->cyclefreq;
 	cycles((uint64_t*)&tos->pcycles);
 	tos->pcycles = -tos->pcycles;
 	tos->kcycles = tos->pcycles;

sys/src/9/port/sysseg.c

@@ -96,7 +96,7 @@ ibrk(uintptr_t addr, int seg)
 	if(addr < s->base)
 		addr = s->base;
 
-	pgsz = machp()->pgsz[s->pgszi];
+	pgsz = sys->pgsz[s->pgszi];
 	newtop = ROUNDUP(addr, pgsz);
 	newsize = (newtop-s->base)/pgsz;
 	if(newtop < s->top) {

sys/src/9/port/taslock.c

@@ -249,7 +249,6 @@ canlock(Lock *l)
 		up->lastlock = l;
 	l->_pc = getcallerpc(&l);
 	l->p = up;
-	l->m = machp();
 	l->isilock = 0;
 	if(LOCKCYCLES)
 		cycles(&l->lockcycles);