ref: a141f4c53a32d8227f9a490a8e4f7d87445c47d1
dir: /sys/src/9/bitsy/trap.c/
#include "u.h"
#include "../port/lib.h"
#include "mem.h"
#include "dat.h"
#include "fns.h"
#include "io.h"
#include "ureg.h"
#include "../port/error.h"
#include "tos.h"
Intrregs *intrregs;
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[32];
static Vctl *gpiovctl[27];
static int gpioirqref[12];
/*
* Layout at virtual address 0.
*/
typedef struct Vpage0 {
void (*vectors[8])(void);
ulong vtable[8];
} Vpage0;
Vpage0 *vpage0;
static int irq(Ureg*);
static void gpiointr(Ureg*, void*);
/* recover state after power suspend
* NB: to help debugging bad suspend code,
* I changed some prints below to iprints,
* to avoid deadlocks when a panic is being
* issued during the suspend/resume handler.
*/
void
trapresume(void)
{
vpage0 = (Vpage0*)EVECTORS;
memmove(vpage0->vectors, vectors, sizeof(vpage0->vectors));
memmove(vpage0->vtable, vtable, sizeof(vpage0->vtable));
wbflush();
mappedIvecEnable();
}
/*
* set up for exceptions
*/
void
trapinit(void)
{
/* set up the exception vectors */
vpage0 = (Vpage0*)EVECTORS;
memmove(vpage0->vectors, vectors, sizeof(vpage0->vectors));
memmove(vpage0->vtable, vtable, sizeof(vpage0->vtable));
wbflush();
/* use exception vectors at 0xFFFF0000 */
mappedIvecEnable();
/* set up the stacks for the interrupt modes */
setr13(PsrMfiq, m->sfiq);
setr13(PsrMirq, m->sirq);
setr13(PsrMabt, m->sabt);
setr13(PsrMund, m->sund);
/* map in interrupt registers */
intrregs = mapspecial(INTRREGS, sizeof(*intrregs));
/* make all interrupts IRQ (i.e. not FIQ) and disable all interrupts */
intrregs->iclr = 0;
intrregs->icmr = 0;
/* turn off all gpio interrupts */
gpioregs->rising = 0;
gpioregs->falling = 0;
gpioregs->edgestatus = gpioregs->edgestatus;
/* allow all enabled interrupts to take processor out of sleep mode */
intrregs->iccr = 0;
}
void
trapdump(char *tag)
{
iprint("%s: icip %lux icmr %lux iclr %lux iccr %lux icfp %lux\n",
tag, intrregs->icip, intrregs->icmr, intrregs->iclr,
intrregs->iccr, intrregs->icfp);
}
void
warnregs(Ureg *ur, char *tag)
{
char buf[1024];
char *e = buf+sizeof(buf);
char *p;
p = seprint(buf, e, "%s:\n", tag);
p = seprint(p, e, "type 0x%.8lux psr 0x%.8lux pc 0x%.8lux\n",
ur->type, ur->psr, ur->pc);
p = seprint(p, e, "r0 0x%.8lux r1 0x%.8lux r2 0x%.8lux r3 0x%.8lux\n",
ur->r0, ur->r1, ur->r2, ur->r3);
p = seprint(p, e, "r4 0x%.8lux r5 0x%.8lux r6 0x%.8lux r7 0x%.8lux\n",
ur->r4, ur->r5, ur->r6, ur->r7);
p = seprint(p, e, "r8 0x%.8lux r9 0x%.8lux r10 0x%.8lux r11 0x%.8lux\n",
ur->r8, ur->r9, ur->r10, ur->r11);
seprint(p, e, "r12 0x%.8lux r13 0x%.8lux r14 0x%.8lux\n",
ur->r12, ur->r13, ur->r14);
iprint("%s", buf);
}
/*
* enable an irq interrupt
*/
static void
irqenable(int irq, IntrHandler *f, void* a, char *name)
{
Vctl *v;
if(irq >= nelem(vctl) || irq < 0)
panic("intrenable");
v = malloc(sizeof(Vctl));
v->f = f;
v->a = a;
v->name = xalloc(strlen(name)+1);
strcpy(v->name, name);
lock(&vctllock);
v->next = vctl[irq];
vctl[irq] = v;
intrregs->icmr |= 1<<irq;
unlock(&vctllock);
}
/*
* disable an irq interrupt
*/
static void
irqdisable(int irq, IntrHandler *f, void* a, char *name)
{
Vctl **vp, *v;
if(irq >= nelem(vctl) || irq < 0)
panic("intrdisable");
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);
intrregs->icmr &= ~(1<<irq);
}
unlock(&vctllock);
}
/*
* enable an interrupt
*/
void
intrenable(int type, int which, IntrHandler *f, void* a, char *name)
{
int irq;
Vctl *v;
if(type == IRQ){
irqenable(which, f, a, name);
return;
}
/* from here down, it must be a GPIO edge interrupt */
irq = which;
if(which >= nelem(gpiovctl) || which < 0)
panic("intrenable");
if(which > 11)
irq = 11;
/* the pin had better be configured as input */
if((1<<which) & gpioregs->direction)
panic("intrenable of output pin %d", which);
/* create a second level vctl for the gpio edge interrupt */
v = malloc(sizeof(Vctl));
v->f = f;
v->a = a;
v->name = xalloc(strlen(name)+1);
strcpy(v->name, name);
lock(&vctllock);
v->next = gpiovctl[which];
gpiovctl[which] = v;
/* set edge register to enable interrupt */
switch(type){
case GPIOboth:
gpioregs->rising |= 1<<which;
gpioregs->falling |= 1<<which;
break;
case GPIOfalling:
gpioregs->falling |= 1<<which;
break;
case GPIOrising:
gpioregs->rising |= 1<<which;
break;
}
unlock(&vctllock);
/* point the irq to the gpio interrupt handler */
if(gpioirqref[irq]++ == 0)
irqenable(irq, gpiointr, nil, "gpio edge");
}
/*
* disable an interrupt
*/
void
intrdisable(int type, int which, IntrHandler *f, void* a, char *name)
{
int irq;
Vctl **vp, *v;
if(type == IRQ){
irqdisable(which, f, a, name);
return;
}
/* from here down, it must be a GPIO edge interrupt */
irq = which;
if(which >= nelem(gpiovctl) || which < 0)
panic("intrdisable");
if(which > 11)
irq = 11;
lock(&vctllock);
for(vp = &gpiovctl[which]; v = *vp; vp = &v->next)
if (v->f == f && v->a == a && strcmp(v->name, name) == 0){
break;
}
if (gpiovctl[which] == nil){
/* set edge register to enable interrupt */
switch(type){
case GPIOboth:
print("intrdisable: gpio-rising+falling clear bit %d\n", which);
gpioregs->rising &= ~(1<<which);
gpioregs->falling &= ~(1<<which);
break;
case GPIOfalling:
print("intrdisable: gpio-falling clear bit %d\n", which);
gpioregs->falling &= ~(1<<which);
break;
case GPIOrising:
print("intrdisable: gpio-rising clear bit %d\n", which);
gpioregs->rising &= ~(1<<which);
break;
}
}
if (v) {
print("intrdisable: removing %s\n", name);
*vp = v->next;
}else
print("intrdisable: which %d, name %s not enabled\n", which, name);
unlock(&vctllock);
/* disable the gpio interrupt handler if necessary */
if(--gpioirqref[irq] == 0){
print("intrdisable: inrqdisable gpiointr\n");
irqdisable(irq, gpiointr, nil, "gpio edge");
}
free(v);
}
/*
* called by trap to handle access faults
*/
static void
faultarm(Ureg *ureg, ulong va, int user, int read)
{
int n, insyscall;
char buf[ERRMAX];
if (up == nil) {
warnregs(ureg, "kernel fault");
panic("fault: nil up in faultarm, accessing 0x%lux", va);
}
insyscall = up->insyscall;
up->insyscall = 1;
n = fault(va, read);
if(n < 0){
if(!user){
warnregs(ureg, "kernel fault");
panic("fault: kernel accessing 0x%lux", va);
}
// warnregs(ureg, "user fault");
sprint(buf, "sys: trap: fault %s va=0x%lux", read ? "read" : "write", va);
postnote(up, 1, buf, NDebug);
}
up->insyscall = insyscall;
}
/*
* 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;
}
/*
* here on all exceptions other than syscall (SWI)
*/
void
trap(Ureg *ureg)
{
ulong inst;
int clockintr, user, x, rv;
ulong va, fsr;
char buf[ERRMAX];
int rem;
if(up != nil)
rem = ((char*)ureg)-up->kstack;
else
rem = ((char*)ureg)-((char*)(MACHADDR+sizeof(Mach)));
if(rem < 256) {
dumpstack();
panic("trap %d bytes remaining, up = %#p, ureg = %#p, at pc 0x%lux",
rem, up, ureg, ureg->pc);
}
user = (ureg->psr & PsrMask) == PsrMusr;
/*
* 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;
switch(ureg->type){
default:
panic("unknown trap");
break;
case PsrMirq:
clockintr = irq(ureg);
break;
case PsrMabt: /* prefetch fault */
faultarm(ureg, ureg->pc, user, 1);
break;
case PsrMabt+1: /* data fault */
va = getfar();
inst = *(ulong*)(ureg->pc);
fsr = getfsr() & 0xf;
switch(fsr){
case 0x0:
panic("vector exception at %lux", ureg->pc);
break;
case 0x1:
case 0x3:
if(user){
snprint(buf, sizeof(buf), "sys: alignment: pc 0x%lux va 0x%lux\n",
ureg->pc, va);
postnote(up, 1, buf, NDebug);
} else
panic("kernel alignment: pc 0x%lux va 0x%lux", ureg->pc, va);
break;
case 0x2:
panic("terminal exception at %lux", ureg->pc);
break;
case 0x4:
case 0x6:
case 0x8:
case 0xa:
case 0xc:
case 0xe:
panic("external abort 0x%lux pc 0x%lux addr 0x%lux", fsr, ureg->pc, va);
break;
case 0x5:
case 0x7:
/* translation fault, i.e., no pte entry */
faultarm(ureg, va, user, !writetomem(inst));
break;
case 0x9:
case 0xb:
/* domain fault, accessing something we shouldn't */
if(user){
sprint(buf, "sys: access violation: pc 0x%lux va 0x%lux\n",
ureg->pc, va);
postnote(up, 1, buf, NDebug);
} else
panic("kernel access violation: pc 0x%lux va 0x%lux",
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) {
/* look for floating point instructions to interpret */
x = spllo();
rv = fpiarm(ureg);
splx(x);
if (rv == 0) {
sprint(buf, "undefined instruction: pc 0x%lux\n", ureg->pc);
postnote(up, 1, buf, NDebug);
}
}else{
iprint("undefined instruction: pc=0x%lux, inst=0x%lux, 0x%lux, 0x%lux, 0x%lux, 0x%lux\n", ureg->pc, ((ulong*)ureg->pc)[-2], ((ulong*)ureg->pc)[-1], ((ulong*)ureg->pc)[0], ((ulong*)ureg->pc)[1], ((ulong*)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){
sched();
splhi();
}
if(user){
if(up->procctl || up->nnote)
notify(ureg);
kexit(ureg);
}
}
/*
* here on irq's
*/
static int
irq(Ureg *ur)
{
ulong va;
int clockintr, i;
Vctl *v;
va = intrregs->icip;
if(va & (1<<IRQtimer0))
clockintr = 1;
else
clockintr = 0;
for(i = 0; i < 32; i++){
if(((1<<i) & va) == 0)
continue;
for(v = vctl[i]; v != nil; v = v->next){
v->f(ur, v->a);
va &= ~(1<<i);
}
}
if(va)
print("unknown interrupt: %lux\n", va);
return clockintr;
}
/*
* here on gpio interrupts
*/
static void
gpiointr(Ureg *ur, void*)
{
ulong va;
int i;
Vctl *v;
va = gpioregs->edgestatus;
gpioregs->edgestatus = va;
for(i = 0; i < 27; i++){
if(((1<<i) & va) == 0)
continue;
for(v = gpiovctl[i]; v != nil; v = v->next){
v->f(ur, v->a);
va &= ~(1<<i);
}
}
if(va)
print("unknown gpio interrupt: %lux\n", va);
}
/*
* system calls
*/
#include "../port/systab.h"
/*
* Syscall is called directly from assembler without going through trap().
*/
void
syscall(Ureg* ureg)
{
char *e;
ulong sp;
long ret;
int i, scallnr;
if((ureg->psr & PsrMask) != PsrMusr) {
panic("syscall: pc 0x%lux r14 0x%lux cs 0x%lux", ureg->pc, ureg->r14, ureg->psr);
}
m->syscall++;
up->insyscall = 1;
up->pc = ureg->pc;
up->dbgreg = ureg;
scallnr = ureg->r0;
up->scallnr = scallnr;
spllo();
sp = ureg->sp;
up->nerrlab = 0;
ret = -1;
if(!waserror()){
if(scallnr >= nsyscall){
pprint("bad sys call number %d pc %lux\n",
scallnr, ureg->pc);
postnote(up, 1, "sys: bad sys call", NDebug);
error(Ebadarg);
}
if(sp<(USTKTOP-BY2PG) || sp>(USTKTOP-sizeof(Sargs)-BY2WD))
validaddr(sp, sizeof(Sargs)+BY2WD, 0);
up->s = *((Sargs*)(sp+BY2WD));
up->psstate = sysctab[scallnr];
ret = systab[scallnr]((va_list)up->s.args);
poperror();
}else{
/* failure: save the error buffer for errstr */
e = up->syserrstr;
up->syserrstr = up->errstr;
up->errstr = e;
}
if(up->nerrlab){
print("bad errstack [%d]: %d extra\n", scallnr, up->nerrlab);
for(i = 0; i < NERR; i++)
print("sp=%lux pc=%lux\n",
up->errlab[i].sp, up->errlab[i].pc);
panic("error stack");
}
up->insyscall = 0;
up->psstate = 0;
/*
* Put return value in frame. On the x86 the syscall is
* just another trap and the return value from syscall is
* ignored. On other machines the return value is put into
* the results register by caller of syscall.
*/
ureg->r0 = ret;
if(scallnr == NOTED)
noted(ureg, *(ulong*)(sp+BY2WD));
if(up->delaysched)
sched();
splhi();
if(scallnr != RFORK && (up->procctl || up->nnote))
notify(ureg);
}
/*
* Return user to state before notify()
*/
void
noted(Ureg* ureg, ulong arg0)
{
Ureg *nureg;
ulong oureg, sp;
qlock(&up->debug);
if(arg0!=NRSTR && !up->notified) {
qunlock(&up->debug);
pprint("call to noted() when not notified\n");
pexit("Suicide", 0);
}
up->notified = 0;
nureg = up->ureg; /* pointer to user returned Ureg struct */
/* sanity clause */
oureg = (ulong)nureg;
if(!okaddr(oureg-BY2WD, BY2WD+sizeof(Ureg), 0)){
qunlock(&up->debug);
pprint("bad ureg in noted or call to noted when not notified\n");
pexit("Suicide", 0);
}
/* don't let user change system flags */
nureg->psr = (ureg->psr & ~(PsrMask|PsrDfiq|PsrDirq)) |
(nureg->psr & (PsrMask|PsrDfiq|PsrDirq));
memmove(ureg, nureg, sizeof(Ureg));
switch(arg0){
case NCONT:
case NRSTR:
if(!okaddr(nureg->pc, 1, 0) || !okaddr(nureg->sp, BY2WD, 0)){
qunlock(&up->debug);
pprint("suicide: trap in noted\n");
pexit("Suicide", 0);
}
up->ureg = (Ureg*)(*(ulong*)(oureg-BY2WD));
qunlock(&up->debug);
break;
case NSAVE:
if(!okaddr(nureg->pc, BY2WD, 0)
|| !okaddr(nureg->sp, BY2WD, 0)){
qunlock(&up->debug);
pprint("suicide: trap in noted\n");
pexit("Suicide", 0);
}
qunlock(&up->debug);
sp = oureg-4*BY2WD-ERRMAX;
splhi();
ureg->sp = sp;
((ulong*)sp)[1] = oureg; /* arg 1 0(FP) is ureg* */
((ulong*)sp)[0] = 0; /* arg 0 is pc */
break;
default:
up->lastnote.flag = NDebug;
/* fall through */
case NDFLT:
qunlock(&up->debug);
if(up->lastnote.flag == NDebug)
pprint("suicide: %s\n", up->lastnote.msg);
pexit(up->lastnote.msg, up->lastnote.flag!=NDebug);
}
}
/*
* Call user, if necessary, with note.
* Pass user the Ureg struct and the note on his stack.
*/
int
notify(Ureg* ureg)
{
int l;
ulong s, sp;
Note *n;
if(up->procctl)
procctl();
if(up->nnote == 0)
return 0;
s = spllo();
qlock(&up->debug);
up->notepending = 0;
n = &up->note[0];
if(strncmp(n->msg, "sys:", 4) == 0){
l = strlen(n->msg);
if(l > ERRMAX-15) /* " pc=0x12345678\0" */
l = ERRMAX-15;
sprint(n->msg+l, " pc=0x%.8lux", ureg->pc);
}
if(n->flag!=NUser && (up->notified || up->notify==0)){
qunlock(&up->debug);
if(n->flag == NDebug)
pprint("suicide: %s\n", n->msg);
pexit(n->msg, n->flag!=NDebug);
}
if(up->notified) {
qunlock(&up->debug);
splhi();
return 0;
}
if(!up->notify){
qunlock(&up->debug);
pexit(n->msg, n->flag!=NDebug);
}
sp = ureg->sp;
sp -= sizeof(Ureg);
if(!okaddr((uintptr)up->notify, 1, 0)
|| !okaddr(sp-ERRMAX-4*BY2WD, sizeof(Ureg)+ERRMAX+4*BY2WD, 1)){
qunlock(&up->debug);
pprint("suicide: bad address in notify\n");
pexit("Suicide", 0);
}
up->ureg = (void*)sp;
memmove((Ureg*)sp, ureg, sizeof(Ureg));
*(Ureg**)(sp-BY2WD) = up->ureg; /* word under Ureg is old up->ureg */
up->ureg = (void*)sp;
sp -= BY2WD+ERRMAX;
memmove((char*)sp, up->note[0].msg, ERRMAX);
sp -= 3*BY2WD;
*(ulong*)(sp+2*BY2WD) = sp+3*BY2WD; /* arg 2 is string */
*(ulong*)(sp+1*BY2WD) = (ulong)up->ureg; /* arg 1 is ureg* */
*(ulong*)(sp+0*BY2WD) = 0; /* arg 0 is pc */
ureg->sp = sp;
ureg->pc = (ulong)up->notify;
up->notified = 1;
up->nnote--;
memmove(&up->lastnote, &up->note[0], sizeof(Note));
memmove(&up->note[0], &up->note[1], up->nnote*sizeof(Note));
qunlock(&up->debug);
splx(s);
return 1;
}
/* Give enough context in the ureg to produce a kernel stack for
* a sleeping process
*/
void
setkernur(Ureg *ureg, Proc *p)
{
ureg->pc = p->sched.pc;
ureg->sp = p->sched.sp+4;
ureg->r14 = (ulong)sched;
}
/*
* return the userpc the last exception happened at
*/
uintptr
userpc(void)
{
Ureg *ureg;
ureg = (Ureg*)up->dbgreg;
return ureg->pc;
}
/* This routine must save the values of registers the user is not permitted
* to write from devproc and then restore the saved values before returning.
*/
void
setregisters(Ureg* ureg, char* pureg, char* uva, int n)
{
USED(ureg, pureg, uva, n);
}
/*
* this is the body for all kproc's
*/
static void
linkproc(void)
{
spllo();
up->kpfun(up->kparg);
pexit("kproc exiting", 0);
}
/*
* setup stack and initial PC for a new kernel proc. This is architecture
* dependent because of the starting stack location
*/
void
kprocchild(Proc *p, void (*func)(void*), void *arg)
{
p->sched.pc = (ulong)linkproc;
p->sched.sp = (ulong)p->kstack+KSTACK;
p->kpfun = func;
p->kparg = arg;
}
/*
* Craft a return frame which will cause the child to pop out of
* the scheduler in user mode with the return register zero. Set
* pc to point to a l.s return function.
*/
void
forkchild(Proc *p, Ureg *ureg)
{
Ureg *cureg;
//print("%lud setting up for forking child %lud\n", up->pid, p->pid);
p->sched.sp = (ulong)p->kstack+KSTACK-sizeof(Ureg);
p->sched.pc = (ulong)forkret;
cureg = (Ureg*)(p->sched.sp);
memmove(cureg, ureg, sizeof(Ureg));
/* syscall returns 0 for child */
cureg->r0 = 0;
/* Things from bottom of syscall which were never executed */
p->psstate = 0;
p->insyscall = 0;
}
/*
* setup stack, initial PC, and any arch dependent regs for an execing user proc.
*/
uintptr
execregs(uintptr entry, ulong ssize, ulong nargs)
{
ulong *sp;
Ureg *ureg;
sp = (ulong*)(USTKTOP - ssize);
*--sp = nargs;
ureg = up->dbgreg;
memset(ureg, 0, 15*sizeof(ulong));
ureg->r13 = (ulong)sp;
ureg->pc = entry;
//print("%lud: EXECREGS pc 0x%lux sp 0x%lux\n", up->pid, ureg->pc, ureg->r13);
return USTKTOP-sizeof(Tos); /* address of kernel/user shared data */
}
/*
* 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 = (ulong)&fn;
fn(&ureg);
}
static void
_dumpstack(Ureg *ureg)
{
ulong l, v, i;
ulong *p;
extern ulong etext;
if(up == 0){
iprint("no current proc\n");
return;
}
iprint("ktrace /kernel/path %.8lux %.8lux %.8lux\n", ureg->pc, ureg->sp, ureg->r14);
i = 0;
for(l=(ulong)&l; l<(ulong)(up->kstack+KSTACK); l+=4){
v = *(ulong*)l;
if(KTZERO < v && v < (ulong)&etext && (v&3)==0){
v -= 4;
p = (ulong*)v;
if((*p & 0x0f000000) == 0x0b000000){
iprint("%.8lux=%.8lux ", l, v);
i++;
}
}
if(i == 4){
i = 0;
iprint("\n");
}
}
if(i)
iprint("\n");
}
void
dumpstack(void)
{
callwithureg(_dumpstack);
}
/*
* pc output by ps
*/
uintptr
dbgpc(Proc *p)
{
Ureg *ureg;
ureg = p->dbgreg;
if(ureg == 0)
return 0;
return ureg->pc;
}
/*
* called in sysfile.c
*/
void
evenaddr(ulong addr)
{
if(addr & 3){
postnote(up, 1, "sys: odd address", NDebug);
error(Ebadarg);
}
}