xref: /plan9/sys/src/9/omap/trap.c (revision 9b7bf7df4595c26f1e9b67beb0c6e44c9876fb05)

/*
 * omap3530 traps, exceptions, interrupts, system calls.
 */
#include "u.h"
#include "../port/lib.h"
#include "mem.h"
#include "dat.h"
#include "fns.h"
#include "../port/error.h"

#include "ureg.h"
#include "arm.h"

enum {
	Nirqs = 96,
	Nvec = 8,		/* # of vectors at start of lexception.s */
	Bi2long = BI2BY * sizeof(long),
};

extern int notify(Ureg*);

extern int ldrexvalid;

/* omap35x intc (aka mpu_intc) */
typedef struct Intrregs Intrregs;
struct Intrregs {
	/*
	 * the manual inserts "INTCPS_" before each register name;
	 * we'll just assume the prefix.
	 */
	uchar	_pad0[4*4];
	ulong	sysconfig;
	ulong	sysstatus;		/* ro */
	uchar	_pad1[0x40 - 0x18];
	ulong	sir_irq;		/* ro */
	ulong	sir_fiq;		/* ro */
	ulong	control;
	ulong	protection;
	ulong	idle;
	uchar	_pad2[0x60 - 0x54];
	ulong	irq_priority;
	ulong	fiq_priority;
	ulong	threshold;
	uchar	_pad3[0x80 - 0x6c];
	struct Bits {			/* bitmaps */
		ulong	itr;		/* ro: pending intrs (no mask) */
		ulong	mir;		/* interrupt mask: 1 means masked */
		ulong	mir_clear;	/* wo: 1 sets the bit */
		ulong	mir_set;	/* wo: 1 clears the bit */
		ulong	isr_set;	/* software interrupts */
		ulong	isr_clear;	/* wo */
		ulong	pending_irq;	/* ro */
		ulong	pending_fiq;	/* ro */
	} bits[3];			/* 3*32 = 96 (Nirqs) */
	ulong	ilr[Nirqs];
};

enum {
	/* sysconfig bits */
	Softreset	= 1<<1,

	/* sysstatus bits */
	Resetdone	= 1<<0,

	/* sir_irq/fiq bits */
	Activeirq	= MASK(7),

	/* control bits */
	Newirqagr	= 1<<0,

	/* protection bits */
	Protection	= 1<<0,

	/* irq/fiq_priority bits */
	Irqpriority	= MASK(6),

	/* threshold bits */
	Prioritythreshold = MASK(8),

	/* ilr bits */
	Priority	= MASK(8) - MASK(2),
};

typedef struct Vctl Vctl;
typedef struct Vctl {
	Vctl*	next;		/* handlers on this vector */
	char	*name;		/* of driver, xallocated */
	void	(*f)(Ureg*, void*);	/* handler to call */
	void*	a;		/* argument to call it with */
} Vctl;

static Lock vctllock;
static Vctl* vctl[Nirqs];

/*
 *   Layout at virtual address 0.
 */
typedef struct Vpage0 {
	void	(*vectors[Nvec])(void);
	u32int	vtable[Nvec];
} Vpage0;
static Vpage0 *vpage0;

uvlong ninterrupt;
uvlong ninterruptticks;
int irqtooearly = 1;

static volatile int probing, trapped;

static int
irqinuse(uint irq)
{
	Intrregs *ip = (Intrregs *)PHYSINTC;

	/*
	 * mir registers are odd: a 0 bit means intr unmasked (i.e.,
	 * we've unmasked it because it's in use).
	 */
	return (ip->bits[irq / Bi2long].mir & (1 << (irq % Bi2long))) == 0;
}

static void
intcmask(uint irq)
{
	Intrregs *ip = (Intrregs *)PHYSINTC;

	ip->bits[irq / Bi2long].mir_set = 1 << (irq % Bi2long);
	coherence();
}

static void
intcunmask(uint irq)
{
	Intrregs *ip = (Intrregs *)PHYSINTC;

	ip->bits[irq / Bi2long].mir_clear = 1 << (irq % Bi2long);
	coherence();
}

static void
intcmaskall(void)
{
	int i;
	Intrregs *ip = (Intrregs *)PHYSINTC;

	for (i = 0; i < 3; i++)
		ip->bits[i].mir_set = ~0;
	coherence();
}

static void
intcunmaskall(void)
{
	int i;
	Intrregs *ip = (Intrregs *)PHYSINTC;

	for (i = 0; i < 3; i++)
		ip->bits[i].mir_clear = ~0;
	coherence();
}

static void
intcinvertall(void)
{
	int i, s;
	ulong bits;
	Intrregs *ip = (Intrregs *)PHYSINTC;

	s = splhi();
	for (i = 0; i < 3; i++) {
		bits = ip->bits[i].mir;
		ip->bits[i].mir_set = ~0;	/* mask all */
		coherence();
		/* clearing enables only those intrs. that were disabled */
		ip->bits[i].mir_clear = bits;
	}
	coherence();
	splx(s);
}

static void
intrsave(ulong buf[3])
{
	int i;
	Intrregs *ip = (Intrregs *)PHYSINTC;

	for (i = 0; i < nelem(buf); i++)
		buf[i] = ip->bits[i].mir;
	coherence();
}

static void
intrrestore(ulong buf[3])
{
	int i, s;
	Intrregs *ip = (Intrregs *)PHYSINTC;

	s = splhi();
	for (i = 0; i < nelem(buf); i++) {
		ip->bits[i].mir_clear = ~0;	/* unmask all */
		coherence();
		ip->bits[i].mir_set = buf[i];	/* mask previously disabled */
	}
	coherence();
	splx(s);
}

/*
 *  set up for exceptions
 */
void
trapinit(void)
{
	int i;
	Intrregs *ip = (Intrregs *)PHYSINTC;

	/* set up the exception vectors */
	vpage0 = (Vpage0*)HVECTORS;
	memmove(vpage0->vectors, vectors, sizeof(vpage0->vectors));
	memmove(vpage0->vtable, vtable, sizeof(vpage0->vtable));
	cacheuwbinv();
	l2cacheuwbinv();

	/* set up the stacks for the interrupt modes */
	setr13(PsrMfiq, m->sfiq);
	setr13(PsrMirq, m->sirq);
	setr13(PsrMabt, m->sabt);
	setr13(PsrMund, m->sund);
#ifdef HIGH_SECURITY
	setr13(PsrMmon, m->smon);
#endif
	setr13(PsrMsys, m->ssys);

	intcmaskall();
	ip->control = 0;
	ip->threshold = Prioritythreshold;	/* disable threshold */
	for (i = 0; i < Nirqs; i++)
		ip->ilr[i] = 0<<2 | 0;	/* all intrs pri 0 & to irq, not fiq */
	irqtooearly = 0;
	coherence();
}

void
intrsoff(void)
{
	Intrregs *ip = (Intrregs *)PHYSINTC;

	intcmaskall();
	ip->control = Newirqagr;	/* dismiss interrupt */
	coherence();
}

/*
 *  enable an irq interrupt
 */
int
irqenable(int irq, void (*f)(Ureg*, void*), void* a, char *name)
{
	Vctl *v;

	if(irq >= nelem(vctl) || irq < 0)
		panic("irqenable irq %d", irq);

	if (irqtooearly) {
		iprint("irqenable for %d %s called too early\n", irq, name);
		return -1;
	}
	if(irqinuse(irq))
		print("irqenable: %s: irq %d already in use, chaining\n",
			name, irq);
	v = malloc(sizeof(Vctl));
	if (v == nil)
		panic("irqenable: malloc Vctl");
	v->f = f;
	v->a = a;
	v->name = malloc(strlen(name)+1);
	if (v->name == nil)
		panic("irqenable: malloc name");
	strcpy(v->name, name);

	lock(&vctllock);
	v->next = vctl[irq];
	vctl[irq] = v;

	intcunmask(irq);
	unlock(&vctllock);
	return 0;
}

/*
 *  disable an irq interrupt
 */
int
irqdisable(int irq, void (*f)(Ureg*, void*), void* a, char *name)
{
	Vctl **vp, *v;

	if(irq >= nelem(vctl) || irq < 0)
		panic("irqdisable irq %d", irq);

	lock(&vctllock);
	for(vp = &vctl[irq]; v = *vp; vp = &v->next)
		if (v->f == f && v->a == a && strcmp(v->name, name) == 0){
			print("irqdisable: remove %s\n", name);
			*vp = v->next;
			free(v);
			break;
		}

	if(v == nil)
		print("irqdisable: irq %d, name %s not enabled\n", irq, name);
	if(vctl[irq] == nil){
		print("irqdisable: clear icmr bit %d\n", irq);
		intcmask(irq);
	}
	unlock(&vctllock);

	return 0;
}

/*
 *  called by trap to handle access faults
 */
static void
faultarm(Ureg *ureg, uintptr va, int user, int read)
{
	int n, insyscall;
	char buf[ERRMAX];

	if(up == nil) {
		dumpregs(ureg);
		panic("fault: nil up in faultarm, accessing %#p", va);
	}
	insyscall = up->insyscall;
	up->insyscall = 1;
	n = fault(va, read);
	if(n < 0){
		if(!user){
			dumpregs(ureg);
			panic("fault: kernel accessing %#p", va);
		}
		/* don't dump registers; programs suicide all the time */
		snprint(buf, sizeof buf, "sys: trap: fault %s va=%#p",
			read? "read": "write", va);
		postnote(up, 1, buf, NDebug);
	}
	up->insyscall = insyscall;
}

/*
 *  called by trap to handle interrupts.
 *  returns true iff a clock interrupt, thus maybe reschedule.
 */
static int
irq(Ureg* ureg)
{
	int clockintr;
	uint irqno, handled, t, ticks = perfticks();
	Intrregs *ip = (Intrregs *)PHYSINTC;
	Vctl *v;
	static int nesting, lastirq = -1;

	handled = 0;
	irqno = ip->sir_irq & Activeirq;

	if (irqno >= 37 && irqno <= 47)		/* this is a clock intr? */
		m->inclockintr++;		/* yes, count nesting */
	lastirq = irqno;

	if (irqno >= nelem(vctl)) {
		iprint("trap: irq %d >= # vectors (%d)\n", irqno, nelem(vctl));
		ip->control = Newirqagr;	/* dismiss interrupt */
		return 0;
	}

	++nesting;
	for(v = vctl[irqno]; v != nil; v = v->next)
		if (v->f) {
			if (islo())
				panic("trap: pl0 before trap handler for %s",
					v->name);
			v->f(ureg, v->a);
			if (islo())
				panic("trap: %s lowered pl", v->name);
//			splhi();		/* in case v->f lowered pl */
			handled++;
		}
	if(!handled) {
		iprint("unexpected interrupt: irq %d", irqno);
		switch (irqno) {
		case 56:
		case 57:
			iprint(" (I⁲C)");
			break;
		case 83:
		case 86:
		case 94:
			iprint(" (MMC)");
			break;
		}

		if(irqno < nelem(vctl)) {
			intcmask(irqno);
			iprint(", now masked");
		}
		iprint("\n");
	}
	t = perfticks();
	ninterrupt++;
	if(t < ticks)
		ninterruptticks += ticks-t;
	else
		ninterruptticks += t-ticks;
	ip->control = Newirqagr;	/* dismiss interrupt */
	coherence();

	--nesting;
	clockintr = m->inclockintr == 1;
	if (irqno >= 37 && irqno <= 47)
		m->inclockintr--;
	return clockintr;
}

/*
 *  returns 1 if the instruction writes memory, 0 otherwise
 */
int
writetomem(ulong inst)
{
	/* swap always write memory */
	if((inst & 0x0FC00000) == 0x01000000)
		return 1;

	/* loads and stores are distinguished by bit 20 */
	if(inst & (1<<20))
		return 0;

	return 1;
}

void	prgpmcerrs(void);

/*
 *  here on all exceptions other than syscall (SWI)
 */
void
trap(Ureg *ureg)
{
	int clockintr, user, x, rv, rem;
	ulong inst, fsr;
	uintptr va;
	char buf[ERRMAX];

	splhi();			/* paranoia */
	if(up != nil)
		rem = ((char*)ureg)-up->kstack;
	else
		rem = ((char*)ureg)-((char*)m+sizeof(Mach));
	if(rem < 1024) {
		iprint("trap: %d stack bytes left, up %#p ureg %#p at pc %#lux\n",
			rem, up, ureg, ureg->pc);
		delay(1000);
		dumpstack();
		panic("trap: %d stack bytes left, up %#p ureg %#p at pc %#lux",
			rem, up, ureg, ureg->pc);
	}

	user = (ureg->psr & PsrMask) == PsrMusr;
	if(user){
		up->dbgreg = ureg;
		cycles(&up->kentry);
	}

	/*
	 * All interrupts/exceptions should be resumed at ureg->pc-4,
	 * except for Data Abort which resumes at ureg->pc-8.
	 */
	if(ureg->type == (PsrMabt+1))
		ureg->pc -= 8;
	else
		ureg->pc -= 4;

	clockintr = 0;		/* if set, may call sched() before return */
	switch(ureg->type){
	default:
		panic("unknown trap; type %#lux, psr mode %#lux", ureg->type,
			ureg->psr & PsrMask);
		break;
	case PsrMirq:
		ldrexvalid = 0;
		clockintr = irq(ureg);
		m->intr++;
		break;
	case PsrMabt:			/* prefetch fault */
		ldrexvalid = 0;
		x = ifsrget();
		fsr = (x>>7) & 0x8 | x & 0x7;
		switch(fsr){
		case 0x02:		/* instruction debug event (BKPT) */
			if(user){
				snprint(buf, sizeof buf, "sys: breakpoint");
				postnote(up, 1, buf, NDebug);
			}else{
				iprint("kernel bkpt: pc %#lux inst %#ux\n",
					ureg->pc, *(u32int*)ureg->pc);
				panic("kernel bkpt");
			}
			break;
		default:
			faultarm(ureg, ureg->pc, user, 1);
			break;
		}
		break;
	case PsrMabt+1:			/* data fault */
		ldrexvalid = 0;
		va = farget();
		inst = *(ulong*)(ureg->pc);
		/* bits 12 and 10 have to be concatenated with status */
		x = fsrget();
		fsr = (x>>7) & 0x20 | (x>>6) & 0x10 | x & 0xf;
		if (probing && !user) {
			if (trapped++ > 0)
				panic("trap: recursive probe %#lux", va);
			ureg->pc += 4;	/* continue at next instruction */
			break;
		}
		switch(fsr){
		default:
		case 0xa:		/* ? was under external abort */
			panic("unknown data fault, 6b fsr %#lux", fsr);
			break;
		case 0x0:
			panic("vector exception at %#lux", ureg->pc);
			break;
		case 0x1:		/* alignment fault */
		case 0x3:		/* access flag fault (section) */
			if(user){
				snprint(buf, sizeof buf,
					"sys: alignment: pc %#lux va %#p\n",
					ureg->pc, va);
				postnote(up, 1, buf, NDebug);
			} else
				panic("kernel alignment: pc %#lux va %#p", ureg->pc, va);
			break;
		case 0x2:
			panic("terminal exception at %#lux", ureg->pc);
			break;
		case 0x4:		/* icache maint fault */
		case 0x6:		/* access flag fault (page) */
		case 0x8:		/* precise external abort, non-xlat'n */
		case 0x28:
		case 0xc:		/* l1 translation, precise ext. abort */
		case 0x2c:
		case 0xe:		/* l2 translation, precise ext. abort */
		case 0x2e:
		case 0x16:		/* imprecise ext. abort, non-xlt'n */
		case 0x36:
			panic("external abort %#lux pc %#lux addr %#p",
				fsr, ureg->pc, va);
			break;
		case 0x1c:		/* l1 translation, precise parity err */
		case 0x1e:		/* l2 translation, precise parity err */
		case 0x18:		/* imprecise parity or ecc err */
			panic("translation parity error %#lux pc %#lux addr %#p",
				fsr, ureg->pc, va);
			break;
		case 0x5:		/* translation fault, no section entry */
		case 0x7:		/* translation fault, no page entry */
			faultarm(ureg, va, user, !writetomem(inst));
			break;
		case 0x9:
		case 0xb:
			/* domain fault, accessing something we shouldn't */
			if(user){
				snprint(buf, sizeof buf,
					"sys: access violation: pc %#lux va %#p\n",
					ureg->pc, va);
				postnote(up, 1, buf, NDebug);
			} else
				panic("kernel access violation: pc %#lux va %#p",
					ureg->pc, va);
			break;
		case 0xd:
		case 0xf:
			/* permission error, copy on write or real permission error */
			faultarm(ureg, va, user, !writetomem(inst));
			break;
		}
		break;
	case PsrMund:			/* undefined instruction */
		if(user){
			if(seg(up, ureg->pc, 0) != nil &&
			   *(u32int*)ureg->pc == 0xD1200070){
				snprint(buf, sizeof buf, "sys: breakpoint");
				postnote(up, 1, buf, NDebug);
			}else{
				/* look for floating point instructions to interpret */
				x = spllo();
				rv = fpiarm(ureg);
				splx(x);
				if(rv == 0){
					ldrexvalid = 0;
					snprint(buf, sizeof buf,
						"undefined instruction: pc %#lux\n",
						ureg->pc);
					postnote(up, 1, buf, NDebug);
				}
			}
		}else{
			if (ureg->pc & 3) {
				iprint("rounding fault pc %#lux down to word\n",
					ureg->pc);
				ureg->pc &= ~3;
			}
			iprint("undefined instruction: pc %#lux inst %#ux\n",
				ureg->pc, ((u32int*)ureg->pc)[-2]);
			panic("undefined instruction");
		}
		break;
	}
	splhi();

	/* delaysched set because we held a lock or because our quantum ended */
	if(up && up->delaysched && clockintr){
		ldrexvalid = 0;
		sched();		/* can cause more traps */
		splhi();
	}

	if(user){
		if(up->procctl || up->nnote)
			notify(ureg);
		kexit(ureg);
	}
}

/*
 * Fill in enough of Ureg to get a stack trace, and call a function.
 * Used by debugging interface rdb.
 */
void
callwithureg(void (*fn)(Ureg*))
{
	Ureg ureg;

	ureg.pc = getcallerpc(&fn);
	ureg.sp = PTR2UINT(&fn);
	fn(&ureg);
}

static void
dumpstackwithureg(Ureg *ureg)
{
	int x;
	uintptr l, v, i, estack;
	char *s;

	dumpregs(ureg);
	if((s = getconf("*nodumpstack")) != nil && strcmp(s, "0") != 0){
		iprint("dumpstack disabled\n");
		return;
	}
	iprint("dumpstack\n");

	x = 0;
	x += iprint("ktrace /kernel/path %#.8lux %#.8lux %#.8lux # pc, sp, link\n",
		ureg->pc, ureg->sp, ureg->r14);
	delay(20);
	i = 0;
	if(up
	&& (uintptr)&l >= (uintptr)up->kstack
	&& (uintptr)&l <= (uintptr)up->kstack+KSTACK)
		estack = (uintptr)up->kstack+KSTACK;
	else if((uintptr)&l >= (uintptr)m->stack
	&& (uintptr)&l <= (uintptr)m+MACHSIZE)
		estack = (uintptr)m+MACHSIZE;
	else
		return;
	x += iprint("estackx %p\n", estack);

	for(l = (uintptr)&l; l < estack; l += sizeof(uintptr)){
		v = *(uintptr*)l;
		if((KTZERO < v && v < (uintptr)etext) || estack-l < 32){
			x += iprint("%.8p ", v);
			delay(20);
			i++;
		}
		if(i == 8){
			i = 0;
			x += iprint("\n");
			delay(20);
		}
	}
	if(i)
		iprint("\n");
}

void
dumpstack(void)
{
	callwithureg(dumpstackwithureg);
}

/*
 * dump system control coprocessor registers
 */
static void
dumpscr(void)
{
	iprint("0:\t%#8.8ux id\n", cpidget());
	iprint("\t%8.8#ux ct\n", cpctget());
	iprint("1:\t%#8.8ux control\n", controlget());
	iprint("2:\t%#8.8ux ttb\n", ttbget());
	iprint("3:\t%#8.8ux dac\n", dacget());
	iprint("4:\t(reserved)\n");
	iprint("5:\t%#8.8ux fsr\n", fsrget());
	iprint("6:\t%#8.8ux far\n", farget());
	iprint("7:\twrite-only cache\n");
	iprint("8:\twrite-only tlb\n");
	iprint("13:\t%#8.8ux pid\n", pidget());
	delay(10);
}

/*
 * dump general registers
 */
static void
dumpgpr(Ureg* ureg)
{
	if(up != nil)
		iprint("cpu%d: registers for %s %lud\n",
			m->machno, up->text, up->pid);
	else
		iprint("cpu%d: registers for kernel\n", m->machno);

	delay(20);
	iprint("%#8.8lux\tr0\n", ureg->r0);
	iprint("%#8.8lux\tr1\n", ureg->r1);
	iprint("%#8.8lux\tr2\n", ureg->r2);
	delay(20);
	iprint("%#8.8lux\tr3\n", ureg->r3);
	iprint("%#8.8lux\tr4\n", ureg->r4);
	iprint("%#8.8lux\tr5\n", ureg->r5);
	delay(20);
	iprint("%#8.8lux\tr6\n", ureg->r6);
	iprint("%#8.8lux\tr7\n", ureg->r7);
	iprint("%#8.8lux\tr8\n", ureg->r8);
	delay(20);
	iprint("%#8.8lux\tr9 (up)\n", ureg->r9);
	iprint("%#8.8lux\tr10 (m)\n", ureg->r10);
	iprint("%#8.8lux\tr11 (loader temporary)\n", ureg->r11);
	iprint("%#8.8lux\tr12 (SB)\n", ureg->r12);
	delay(20);
	iprint("%#8.8lux\tr13 (sp)\n", ureg->r13);
	iprint("%#8.8lux\tr14 (link)\n", ureg->r14);
	iprint("%#8.8lux\tr15 (pc)\n", ureg->pc);
	delay(20);
	iprint("%10.10lud\ttype\n", ureg->type);
	iprint("%#8.8lux\tpsr\n", ureg->psr);
	delay(20);
}

void
dumpregs(Ureg* ureg)
{
	dumpgpr(ureg);
	dumpscr();
}

vlong
probeaddr(uintptr addr)
{
	vlong v;
	static Lock fltlck;

	ilock(&fltlck);
	trapped = 0;
	probing = 1;
	coherence();

	v = *(ulong *)addr;	/* this may cause a fault */
	USED(probing);
	coherence();

	probing = 0;
	coherence();
	if (trapped)
		v = -1;
	iunlock(&fltlck);
	return v;
}