ref: a8d00e5d56b261376410c3c87c46327362763bd8
dir: /sys/src/9/sgi/trap.c/
/*
* traps, exceptions, faults and interrupts on ar7161
*/
#include "u.h"
#include "../port/lib.h"
#include "mem.h"
#include "dat.h"
#include "fns.h"
#include "ureg.h"
#include "io.h"
#include <tos.h>
#include "../port/error.h"
typedef struct Handler Handler;
struct Handler {
void (*handler)(Ureg*, void *);
void *arg;
Handler *next; /* at this interrupt level */
};
int intr(Ureg*);
void kernfault(Ureg*, int);
void noted(Ureg*, ulong);
void rfnote(Ureg**);
char *excname[] =
{
"trap: external interrupt",
"trap: TLB modification (store to unwritable)",
"trap: TLB miss (load or fetch)",
"trap: TLB miss (store)",
"trap: address error (load or fetch)",
"trap: address error (store)",
"trap: bus error (fetch)",
"trap: bus error (data load or store)",
"trap: system call",
"breakpoint",
"trap: reserved instruction",
"trap: coprocessor unusable",
"trap: arithmetic overflow",
"trap: TRAP exception",
"trap: VCE (instruction)",
"trap: floating-point exception",
"trap: coprocessor 2 implementation-specific", /* used as sys call for debugger */
"trap: corextend unusable",
"trap: precise coprocessor 2 exception",
"trap: TLB read-inhibit",
"trap: TLB execute-inhibit",
"trap: undefined 21",
"trap: undefined 22",
"trap: WATCH exception",
"trap: machine checkcore",
"trap: undefined 25",
"trap: undefined 26",
"trap: undefined 27",
"trap: undefined 28",
"trap: undefined 29",
"trap: cache error",
"trap: VCE (data)",
};
char *fpcause[] =
{
"inexact operation",
"underflow",
"overflow",
"division by zero",
"invalid operation",
};
char *fpexcname(Ureg*, ulong, char*, uint);
#define FPEXPMASK (0x3f<<12) /* Floating exception bits in fcr31 */
struct {
char *name;
uint off;
} regname[] = {
"STATUS", offsetof(Ureg, status),
"PC", offsetof(Ureg, pc),
"SP", offsetof(Ureg, sp),
"CAUSE",offsetof(Ureg, cause),
"BADADDR", offsetof(Ureg, badvaddr),
"TLBVIRT", offsetof(Ureg, tlbvirt),
"HI", offsetof(Ureg, hi),
"LO", offsetof(Ureg, lo),
"R31", offsetof(Ureg, r31),
"R30", offsetof(Ureg, r30),
"R28", offsetof(Ureg, r28),
"R27", offsetof(Ureg, r27),
"R26", offsetof(Ureg, r26),
"R25", offsetof(Ureg, r25),
"R24", offsetof(Ureg, r24),
"R23", offsetof(Ureg, r23),
"R22", offsetof(Ureg, r22),
"R21", offsetof(Ureg, r21),
"R20", offsetof(Ureg, r20),
"R19", offsetof(Ureg, r19),
"R18", offsetof(Ureg, r18),
"R17", offsetof(Ureg, r17),
"R16", offsetof(Ureg, r16),
"R15", offsetof(Ureg, r15),
"R14", offsetof(Ureg, r14),
"R13", offsetof(Ureg, r13),
"R12", offsetof(Ureg, r12),
"R11", offsetof(Ureg, r11),
"R10", offsetof(Ureg, r10),
"R9", offsetof(Ureg, r9),
"R8", offsetof(Ureg, r8),
"R7", offsetof(Ureg, r7),
"R6", offsetof(Ureg, r6),
"R5", offsetof(Ureg, r5),
"R4", offsetof(Ureg, r4),
"R3", offsetof(Ureg, r3),
"R2", offsetof(Ureg, r2),
"R1", offsetof(Ureg, r1),
};
static Handler handlers[8];
void
kvce(Ureg *ur, int ecode)
{
char c;
Pte **p;
Page **pg;
Segment *s;
ulong addr, soff;
c = 'D';
if(ecode == CVCEI)
c = 'I';
print("Trap: VCE%c: addr=%#lux\n", c, ur->badvaddr);
if(up && !(ur->badvaddr & KSEGM)) {
addr = ur->badvaddr;
s = seg(up, addr, 0);
if(s == nil){
print("kvce: no seg for %#lux\n", addr);
for(;;);
}
addr &= ~(BY2PG-1);
soff = addr - s->base;
p = &s->map[soff/PTEMAPMEM];
if(*p){
pg = &(*p)->pages[(soff&(PTEMAPMEM-1))/BY2PG];
if(*pg)
print("kvce: pa=%#lux, va=%#lux\n",
(*pg)->pa, (*pg)->va);
else
print("kvce: no *pg\n");
}else
print("kvce: no *p\n");
}
}
/* prepare to go to user space */
void
kexit(Ureg *ur)
{
Tos *tos;
/* replicate fpstate to ureg status */
if(up->fpstate != FPactive)
ur->status &= ~CU1;
/* precise time accounting, kernel exit */
tos = (Tos*)(USTKTOP-sizeof(Tos));
tos->kcycles += fastticks(&tos->cyclefreq) - up->kentry;
tos->pcycles = up->pcycles;
tos->pid = up->pid;
}
void
trap(Ureg *ur)
{
int ecode, clockintr, user, cop, x, fpchk;
ulong fpfcr31;
char buf[2*ERRMAX], buf1[ERRMAX], *fpexcep;
static int dumps;
if (up && (char *)(ur) - up->kstack < 1024 && dumps++ == 0) {
iprint("trap: proc %ld kernel stack getting full\n", up->pid);
dumpregs(ur);
dumpstack();
for(;;);
}
if (up == nil &&
(char *)(ur) - (char *)m->stack < 1024 && dumps++ == 0) {
iprint("trap: cpu%d kernel stack getting full\n", m->machno);
dumpregs(ur);
dumpstack();
for(;;);
}
ecode = (ur->cause>>2)&EXCMASK;
user = userureg(ur);
if (ur->cause & TS)
panic("trap: tlb shutdown");
fpchk = 0;
if(user){
up->dbgreg = ur;
cycles(&up->kentry);
}
clockintr = 0;
switch(ecode){
case CINT:
clockintr = intr(ur);
break;
case CFPE:
if(!user)
goto Default;
if(up->fpstate == FPactive){
savefpregs(&up->fpsave);
up->fpstate = FPinactive;
}
clrfpintr();
fptrap(ur);
fpchk = 1;
break;
case CTLBM:
case CTLBL:
case CTLBS:
if(up == nil || !user && (ur->badvaddr & KSEGM) == KSEG3) {
kfault(ur);
break;
}
x = up->insyscall;
up->insyscall = 1;
spllo();
faultmips(ur, user, ecode);
up->insyscall = x;
break;
case CVCEI:
case CVCED:
kvce(ur, ecode);
goto Default;
case CWATCH:
if(!user)
panic("watchpoint trap from kernel mode pc=%#p",
ur->pc);
// fpwatch(ur);
break;
case CCPU:
cop = (ur->cause>>28)&3;
if(user && up && cop == 1) {
if(up->fpstate & FPillegal) {
/* someone used floating point in a note handler */
postnote(up, 1,
"sys: floating point in note handler",
NDebug);
break;
}
if(up->fpstate == FPinit || up->fpstate == FPinactive){
restfpregs(&up->fpsave, up->fpsave.fpstatus&~FPEXPMASK);
up->fpstate = FPactive;
ur->status |= CU1;
break;
}
fpchk = 1;
break;
}
/* Fallthrough */
Default:
default:
if(user) {
spllo();
snprint(buf, sizeof buf, "sys: %s", excname[ecode]);
postnote(up, 1, buf, NDebug);
break;
}
if (ecode == CADREL || ecode == CADRES)
iprint("kernel addr exception for va %#p pid %#ld %s\n",
ur->badvaddr, (up? up->pid: 0),
(up? up->text: ""));
print("cpu%d: kernel %s pc=%#lux\n",
m->machno, excname[ecode], ur->pc);
dumpregs(ur);
dumpstack();
if(m->machno == 0)
spllo();
exit(1);
}
if(fpchk) {
fpfcr31 = up->fpsave.fpstatus;
if((fpfcr31>>12) & ((fpfcr31>>7)|0x20) & 0x3f) {
spllo();
fpexcep = fpexcname(ur, fpfcr31, buf1, sizeof buf1);
snprint(buf, sizeof buf, "sys: fp: %s", fpexcep);
postnote(up, 1, buf, NDebug);
}
}
splhi();
/* delaysched set because we held a lock or because our quantum ended */
if(up && up->delaysched && clockintr){
sched();
splhi();
}
if(user){
notify(ur);
kexit(ur);
}
}
/* map HPC3 irq to INTR2 */
int
hpc3irqlevel(int irq)
{
*IO(uchar, LIO_0_MASK) |= 1 << (irq & 7);
return 2 + irq/8;
}
/*
* set handlers
*/
void
intrenable(int level, void (*h)(Ureg*, void *), void *arg)
{
Handler *hp;
hp = &handlers[level];
if (hp->handler != nil) { /* occupied? */
/* add a new one at the end of the chain */
for (; hp->next != nil; hp = hp->next)
;
if((hp->next = xalloc(sizeof *hp)) == nil)
panic("intrenable: out of memory");
hp = hp->next;
}
hp->arg = arg;
hp->handler = h;
intron(INTR0 << level);
}
int
intr(Ureg *ur)
{
ulong cause, mask;
int clockintr;
Handler *hh, *hp;
m->intr++;
clockintr = 0;
/*
* ignore interrupts that we have disabled, even if their cause bits
* are set.
*/
cause = ur->cause & ur->status & INTMASK;
cause &= ~(INTR1|INTR0); /* ignore sw interrupts */
if(cause & INTR7){
clock(ur);
cause &= ~INTR7;
clockintr = 1;
}
hh = &handlers[2];
for(mask = INTR2; cause != 0 && mask < INTR7; mask <<= 1){
if(cause & mask){
for(hp = hh; hp != nil; hp = hp->next){
if(hp->handler != nil){
(*hp->handler)(ur, hp->arg);
cause &= ~mask;
}
}
}
hh++;
}
if(cause != 0)
iprint("unhandled interrupts %lux\n", cause);
/* preemptive scheduling */
if(up != nil && !clockintr)
preempted();
/* if it was a clockintr, sched will be called at end of trap() */
return clockintr;
}
char*
fpexcname(Ureg *ur, ulong fcr31, char *buf, uint size)
{
int i;
char *s;
ulong fppc;
fppc = ur->pc;
if(ur->cause & BD) /* branch delay */
fppc += 4;
s = 0;
if(fcr31 & (1<<17))
s = "unimplemented operation";
else{
fcr31 >>= 7; /* trap enable bits */
fcr31 &= (fcr31>>5); /* anded with exceptions */
for(i=0; i<5; i++)
if(fcr31 & (1<<i))
s = fpcause[i];
}
if(s == 0)
return "no floating point exception";
snprint(buf, size, "%s fppc=%#lux", s, fppc);
return buf;
}
static void
getpcsp(ulong *pc, ulong *sp)
{
*pc = getcallerpc(&pc);
*sp = (ulong)&pc-4;
}
void
callwithureg(void (*fn)(Ureg*))
{
Ureg ureg;
memset(&ureg, 0, sizeof ureg);
getpcsp((ulong*)&ureg.pc, (ulong*)&ureg.sp);
ureg.r31 = getcallerpc(&fn);
fn(&ureg);
}
static void
_dumpstack(Ureg *ureg)
{
ulong l, v, top, i;
extern ulong etext;
print("ktrace /kernel/path %.8lux %.8lux %.8lux\n",
ureg->pc, ureg->sp, ureg->r31);
if(up == nil)
top = (ulong)MACHADDR + MACHSIZE;
else
top = (ulong)up->kstack + KSTACK;
i = 0;
for(l=ureg->sp; l < top; l += BY2WD) {
v = *(ulong*)l;
if(KTZERO < v && v < (ulong)&etext) {
print("%.8lux=%.8lux ", l, v);
if((++i%4) == 0){
print("\n");
delay(200);
}
}
}
print("\n");
}
void
dumpstack(void)
{
callwithureg(_dumpstack);
}
static ulong
R(Ureg *ur, int i)
{
uchar *s;
s = (uchar*)ur;
return *(ulong*)(s + regname[i].off);
}
void
dumpregs(Ureg *ur)
{
int i;
if(up)
print("registers for %s %lud\n", up->text, up->pid);
else
print("registers for kernel\n");
for(i = 0; i < nelem(regname); i += 2)
print("%s\t%#.8lux\t%s\t%#.8lux\n",
regname[i].name, R(ur, i),
regname[i+1].name, R(ur, i+1));
}
int
notify(Ureg *ur)
{
int l, s;
ulong sp;
Note *n;
if(up->procctl)
procctl();
if(up->nnote == 0)
return 0;
if(up->fpstate == FPactive){
savefpregs(&up->fpsave);
up->fpstate = FPinactive;
}
up->fpstate |= FPillegal;
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;
seprint(n->msg+l, &n->msg[sizeof n->msg], " pc=%#lux", ur->pc);
}
if(n->flag != NUser && (up->notified || up->notify==0)) {
if(n->flag == NDebug)
pprint("suicide: %s\n", n->msg);
qunlock(&up->debug);
pexit(n->msg, n->flag!=NDebug);
}
if(up->notified) {
qunlock(&up->debug);
splx(s);
return 0;
}
if(!up->notify) {
qunlock(&up->debug);
pexit(n->msg, n->flag!=NDebug);
}
sp = ur->usp & ~(BY2V-1);
sp -= sizeof(Ureg);
if(!okaddr((ulong)up->notify, BY2WD, 0) ||
!okaddr(sp-ERRMAX-4*BY2WD, sizeof(Ureg)+ERRMAX+4*BY2WD, 1)) {
pprint("suicide: bad address or sp in notify\n");
qunlock(&up->debug);
pexit("Suicide", 0);
}
memmove((Ureg*)sp, ur, sizeof(Ureg)); /* push user regs */
*(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); /* push err string */
sp -= 3*BY2WD;
*(ulong*)(sp+2*BY2WD) = sp+3*BY2WD; /* arg 2 is string */
ur->r1 = (long)up->ureg; /* arg 1 is ureg* */
((ulong*)sp)[1] = (ulong)up->ureg; /* arg 1 0(FP) is ureg* */
((ulong*)sp)[0] = 0; /* arg 0 is pc */
ur->usp = sp;
/*
* arrange to resume at user's handler as if handler(ureg, errstr)
* were being called.
*/
ur->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;
}
/*
* Return user to state before notify(); called from user's handler.
*/
void
noted(Ureg *kur, ulong arg0)
{
Ureg *nur;
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;
up->fpstate &= ~FPillegal;
nur = up->ureg;
oureg = (ulong)nur;
if((oureg & (BY2WD-1)) || !okaddr((ulong)oureg-BY2WD, BY2WD+sizeof(Ureg), 0)){
pprint("bad up->ureg in noted or call to noted() when not notified\n");
qunlock(&up->debug);
pexit("Suicide", 0);
}
setregisters(kur, (char*)kur, (char*)up->ureg, sizeof(Ureg));
switch(arg0) {
case NCONT:
case NRSTR: /* only used by APE */
if(!okaddr(nur->pc, BY2WD, 0) || !okaddr(nur->usp, BY2WD, 0)){
pprint("suicide: trap in noted\n");
qunlock(&up->debug);
pexit("Suicide", 0);
}
up->ureg = (Ureg*)(*(ulong*)(oureg-BY2WD));
qunlock(&up->debug);
splhi();
break;
case NSAVE: /* only used by APE */
if(!okaddr(nur->pc, BY2WD, 0) || !okaddr(nur->usp, BY2WD, 0)){
pprint("suicide: trap in noted\n");
qunlock(&up->debug);
pexit("Suicide", 0);
}
qunlock(&up->debug);
sp = oureg-4*BY2WD-ERRMAX;
splhi();
kur->sp = sp;
kur->r1 = oureg; /* arg 1 is ureg* */
((ulong*)sp)[1] = oureg; /* arg 1 0(FP) is ureg* */
((ulong*)sp)[0] = 0; /* arg 0 is pc */
break;
default:
pprint("unknown noted arg %#lux\n", arg0);
up->lastnote.flag = NDebug;
/* fall through */
case NDFLT:
if(up->lastnote.flag == NDebug)
pprint("suicide: %s\n", up->lastnote.msg);
qunlock(&up->debug);
pexit(up->lastnote.msg, up->lastnote.flag!=NDebug);
}
}
#include "../port/systab.h"
static void
sctracesetup(ulong scallnr, ulong sp, uintptr pc, vlong *startnsp)
{
if(up->procctl == Proc_tracesyscall){
/*
* Redundant validaddr. Do we care?
* Tracing syscalls is not exactly a fast path...
* Beware, validaddr currently does a pexit rather
* than an error if there's a problem; that might
* change in the future.
*/
if(sp < (USTKTOP-BY2PG) || sp > (USTKTOP-sizeof(Sargs)-BY2WD))
validaddr(sp, sizeof(Sargs)+BY2WD, 0);
syscallfmt(scallnr, pc, (va_list)(sp+BY2WD));
up->procctl = Proc_stopme;
procctl();
if(up->syscalltrace)
free(up->syscalltrace);
up->syscalltrace = nil;
*startnsp = todget(nil);
}
}
static void
sctracefinish(ulong scallnr, ulong sp, int ret, vlong startns)
{
int s;
if(up->procctl == Proc_tracesyscall){
up->procctl = Proc_stopme;
sysretfmt(scallnr, (va_list)(sp+BY2WD), ret,
startns, todget(nil));
s = splhi();
procctl();
splx(s);
if(up->syscalltrace)
free(up->syscalltrace);
up->syscalltrace = nil;
}
}
/*
* called directly from assembler, not via trap()
*/
void
syscall(Ureg *ur)
{
int i;
volatile long ret;
ulong sp, scallnr;
vlong startns;
char *e;
cycles(&up->kentry);
m->syscall++;
up->insyscall = 1;
up->pc = ur->pc;
up->dbgreg = ur;
ur->cause = 16<<2; /* for debugging: system call is undef 16 */
scallnr = ur->r1;
up->scallnr = ur->r1;
sp = ur->sp;
sctracesetup(scallnr, sp, ur->pc, &startns);
/* no fpu, so no fp state to save */
spllo();
up->nerrlab = 0;
ret = -1;
if(!waserror()) {
if(scallnr >= nsyscall || systab[scallnr] == 0){
pprint("bad sys call number %ld pc %#lux\n",
scallnr, ur->pc);
postnote(up, 1, "sys: bad sys call", NDebug);
error(Ebadarg);
}
if(sp & (BY2WD-1)){
pprint("odd sp in sys call pc %#lux sp %#lux\n",
ur->pc, ur->sp);
postnote(up, 1, "sys: odd stack", 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(0 && up->pid == 1)
print("[%lud %s] syscall %lud: %s\n",
up->pid, up->text, scallnr, up->errstr);
}
if(up->nerrlab){
print("bad errstack [%lud]: %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");
}
sctracefinish(scallnr, sp, ret, startns);
ur->pc += 4;
ur->r1 = ret;
up->psstate = 0;
up->insyscall = 0;
if(scallnr == NOTED) /* ugly hack */
noted(ur, *(ulong*)(sp+BY2WD)); /* may return */
splhi();
if(scallnr!=RFORK && (up->procctl || up->nnote))
notify(ur);
/* if we delayed sched because we held a lock, sched now */
if(up->delaysched)
sched();
kexit(ur);
}
void
forkchild(Proc *p, Ureg *ur)
{
Ureg *cur;
p->sched.sp = (ulong)p->kstack+KSTACK-UREGSIZE;
p->sched.pc = (ulong)forkret;
cur = (Ureg*)(p->sched.sp+2*BY2WD);
memmove(cur, ur, sizeof(Ureg));
cur->status &= ~CU1; /* FPU off when returning */
cur->r1 = 0;
cur->pc += 4;
/* Things from bottom of syscall we never got to execute */
p->psstate = 0;
p->insyscall = 0;
}
static
void
linkproc(void)
{
spllo();
up->kpfun(up->kparg);
pexit("kproc exiting", 0);
}
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;
}
/* set up user registers before return from exec() */
uintptr
execregs(ulong entry, ulong ssize, ulong nargs)
{
Ureg *ur;
ulong *sp;
sp = (ulong*)(USTKTOP - ssize);
*--sp = nargs;
ur = (Ureg*)up->dbgreg;
ur->usp = (ulong)sp;
ur->pc = entry - 4; /* syscall advances it */
return USTKTOP-sizeof(Tos); /* address of kernel/user shared data */
}
ulong
userpc(void)
{
Ureg *ur;
ur = (Ureg*)up->dbgreg;
return ur->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 *xp, char *pureg, char *uva, int n)
{
ulong status, r27;
r27 = xp->r27; /* return PC for GEVector() */
status = xp->status;
memmove(pureg, uva, n);
xp->r27 = r27;
xp->status = status;
}
/*
* Give enough context in the ureg to produce a kernel stack for
* a sleeping process
*/
void
setkernur(Ureg *xp, Proc *p)
{
xp->pc = p->sched.pc;
xp->sp = p->sched.sp;
xp->r24 = (ulong)p; /* up */
xp->r31 = (ulong)sched;
}
ulong
dbgpc(Proc *p)
{
Ureg *ur;
ur = p->dbgreg;
if(ur == 0)
return 0;
return ur->pc;
}