ref: 9f76a7f6819ac04552b4fb6588156f3e4089d1d7
dir: /os/js/trap.c/
#include "u.h"
#include "../port/lib.h"
#include "mem.h"
#include "dat.h"
#include "fns.h"
#include "ureg.h"
#include "io.h"
#include "../port/error.h"
void noted(Ureg**, ulong);
void rfnote(Ureg**);
int domuldiv(ulong, Ureg*);
extern Label catch;
extern void traplink(void);
extern void syslink(void);
static void faultsparc(Ureg *ur);
static void faultasync(Ureg *ur);
long ticks;
static char excbuf[64]; /* BUG: not reentrant! */
char *trapname[]={
"reset",
"instruction access exception",
"illegal instruction",
"privileged instruction",
"fp: disabled",
"window overflow",
"window underflow",
"unaligned address",
"fp: exception",
"data access exception",
"tag overflow",
"watchpoint detected",
};
char *fptrapname[]={
"none",
"IEEE 754 exception",
"unfinished FP op",
"unimplemented FP op",
"sequence error",
"hardware error",
"invalid FP register",
"reserved",
}
;
char*
excname(ulong tbr)
{
char xx[64];
char *t;
switch(tbr){
case 8:
if(up == 0)
panic("fptrap in kernel\n");
else{
panic("fptrap not implemented\n");
#ifdef notdef
if(m->fpunsafe==0 && up->p->fpstate!=FPactive)
panic("fptrap not active\n"); fsr = up->fpsave.env;
sprint(excbuf, "fp: %s fppc=0x%lux",
fptrapname[(fsr>>14)&7],
up->fpsave.q[0].a, fsr);
#endif
}
return excbuf;
case 36:
return "trap: cp disabled";
case 37:
return "trap: unimplemented instruction";
case 40:
return "trap: cp exception";
case 42:
return "trap: divide by zero";
case 128:
return "syscall";
case 129:
return "breakpoint";
}
t = 0;
if(tbr < sizeof trapname/sizeof(char*))
t = trapname[tbr];
if(t == 0){
if(tbr >= 130)
sprint(xx, "trap instruction %ld", tbr-128);
else if(17<=tbr && tbr<=31)
sprint(xx, "interrupt level %ld", tbr-16);
else
sprint(xx, "unknown trap %ld", tbr);
t = xx;
}
if(strncmp(t, "fp: ", 4) == 0)
strcpy(excbuf, t);
else
sprint(excbuf, "trap: %s", t);
return excbuf;
}
void
trap(Ureg *ur)
{
int user;
ulong tbr, iw;
tbr = (ur->tbr&0xFFF)>>4;
/*
* Hack to catch bootstrap fault during probe
*/
if(catch.pc)
gotolabel(&catch);
if(up)
up->dbgreg = ur;
user = !(ur->psr&PSRPSUPER);
if(user) {
panic("how did we get to user mode???");
}
if(tbr > 16){ /* interrupt */
switch(tbr-16) {
case 15: /* asynch mem err */
faultasync(ur);
break;
case 14: /* processor counter */
clock(ur);
break;
case 13: /* keyboard/mouse */
ns16552intr(0);
kbdintr();
break;
case 6: /* lance */
lanceintr();
break;
default:
print("unexp intr lev %ld\n", tbr-16);
goto Error;
}
}else{
switch(tbr){
case 1: /* instr. access */
case 9: /* data access */
if(up && up->fpstate==FPACTIVE) {
fpquiet();
fpsave(&up->fpsave);
up->fpstate = FPINACTIVE;
}
faultsparc(ur);
goto Return;
case 2: /* illegal instr, maybe mul */
iw = *(ulong*)ur->pc;
if((iw&0xC1500000) == 0x80500000){
if(domuldiv(iw, ur))
goto Return;
tbr = ur->tbr;
}
break;
case 4: /* floating point disabled */
panic("some more floating point crapola");
break;
#ifdef notdef
if(u && u->p){
if(up->p->fpstate == FPINIT)
restfpregs(initfpp, up->fpsave.fsr);
else if(u->p->fpstate == FPinactive)
restfpregs(&u->fpsave, u->fpsave.fsr);
else
break;
u->p->fpstate = FPactive;
ur->psr |= PSREF;
return;
}
break;
#endif
case 8: /* floating point exception */
panic("floating point crapola #3");
break;
#ifdef notdef
/* if unsafe, trap happened shutting down FPU; just return */
if(m->fpunsafe){
m->fptrap = (fptrap()==0);
return;
}
if(fptrap())
goto Return; /* handled the problem */
break;
#endif
default:
break;
}
Error:
panic("kernel trap: %s pc=0x%lux\n", excname(tbr), ur->pc);
}
Return:
return;
}
void
trapinit(void)
{
int i;
long t, a;
a = ((ulong)traplink-TRAPS)>>2;
a += 0x40000000; /* CALL traplink(SB) */
t = TRAPS;
for(i=0; i<256; i++){
*(ulong*)(t+0) = a; /* CALL traplink(SB) */
*(ulong*)(t+4) = 0xa7480000; /* MOVW PSR, R19 */
a -= 16/4;
t += 16;
}
#ifdef notdef
flushpage(TRAPS);
#else
flushicache();
#endif
puttbr(TRAPS);
setpsr(getpsr()|PSRET|SPL(15)); /* enable traps, not interrupts */
}
void
mulu(ulong u1, ulong u2, ulong *lop, ulong *hip)
{
ulong lo1, lo2, hi1, hi2, lo, hi, t1, t2, t;
lo1 = u1 & 0xffff;
lo2 = u2 & 0xffff;
hi1 = u1 >> 16;
hi2 = u2 >> 16;
lo = lo1 * lo2;
t1 = lo1 * hi2;
t2 = lo2 * hi1;
hi = hi1 * hi2;
t = lo;
lo += t1 << 16;
if(lo < t)
hi++;
t = lo;
lo += t2 << 16;
if(lo < t)
hi++;
hi += (t1 >> 16) + (t2 >> 16);
*lop = lo;
*hip = hi;
}
void
muls(long l1, long l2, long *lop, long *hip)
{
ulong t, lo, hi;
ulong mlo, mhi;
int sign;
sign = 0;
if(l1 < 0){
sign ^= 1;
l1 = -l1;
}
if(l2 < 0){
sign ^= 1;
l2 = -l2;
}
mulu(l1, l2, &mlo, &mhi);
lo = mlo;
hi = mhi;
if(sign){
t = lo = ~lo;
hi = ~hi;
lo++;
if(lo < t)
hi++;
}
*lop = lo;
*hip = hi;
}
int
domuldiv(ulong iw, Ureg *ur)
{
long op1, op2;
long *regp;
long *regs;
regs = (long*)ur;
if(iw & (1<<13)){ /* signed immediate */
op2 = iw & 0x1FFF;
if(op2 & 0x1000)
op2 |= ~0x1FFF;
}else
op2 = regs[iw&0x1F];
op1 = regs[(iw>>14)&0x1F];
regp = ®s[(iw>>25)&0x1F];
if(iw & (4<<19)){ /* divide */
if(ur->y!=0 && ur->y!=~0){
unimp:
ur->tbr = 37; /* "unimplemented instruction" */
return 0; /* complex Y is too hard */
}
if(op2 == 0){
ur->tbr = 42; /* "zero divide" */
return 0;
}
if(iw & (1<<19)){
if(ur->y && (op1&(1<<31))==0)
goto unimp; /* Y not sign extension */
*regp = op1 / op2;
}else{
if(ur->y)
goto unimp;
*regp = (ulong)op1 / (ulong)op2;
}
}else{
if(iw & (1<<19))
muls(op1, op2, regp, (long*)&ur->y);
else
mulu(op1, op2, (ulong*)regp, &ur->y);
}
if(iw & (16<<19)){ /* set CC */
ur->psr &= ~(0xF << 20);
if(*regp & (1<<31))
ur->psr |= 8 << 20; /* N */
if(*regp == 0)
ur->psr |= 4 << 20; /* Z */
/* BUG: don't get overflow right on divide */
}
ur->pc += 4;
ur->npc = ur->pc+4;
return 1;
}
void
dumpregs(Ureg *ur)
{
int i;
ulong *l;
if(up) {
print("registers for %s %ld\n",up->text,up->pid);
if(ur->usp < (ulong)up->kstack ||
ur->usp > (ulong)up->kstack+KSTACK-8)
print("invalid stack pointer\n");
} else
print("registers for kernel\n");
print("PSR=%lux PC=%lux TBR=%lux\n", ur->psr, ur->pc, ur->tbr);
l = &ur->r0;
for(i=0; i<32; i+=2, l+=2)
print("R%d\t%.8lux\tR%d\t%.8lux\n", i, l[0], i+1, l[1]);
}
/* This routine must save the values of registers the user is not permitted to
* write from devproc and the restore the saved values before returning
*/
void
setregisters(Ureg *xp, char *pureg, char *uva, int n)
{
ulong psr;
psr = xp->psr;
memmove(pureg, uva, n);
xp->psr = psr;
}
void
dumpstack(void)
{
}
/*
* Must only be called splhi() when it is safe to spllo(). Because the FP unit
* traps if you touch it when an exception is pending, and because if you
* trap with ET==0 you halt, this routine sets some global flags to enable
* the rest of the system to handle the trap that might occur here without
* upsetting the kernel. Shouldn't be necessary, but safety first.
*/
int
fpquiet(void)
{
int i, notrap;
ulong fsr;
char buf[128];
i = 0;
notrap = 1;
up->fpstate = FPINACTIVE;
for(;;){
m->fptrap = 0;
fsr = getfsr();
if(m->fptrap){
/* trap occurred and up->fpsave contains state */
sprint(buf, "sys: %s", excname(8));
#ifdef notdef
postnote(u->p, 1, buf, NDebug);
#else
panic(buf);
#endif
notrap = 0;
break;
}
if((fsr&(1<<13)) == 0)
break;
if(++i > 1000){
print("fp not quiescent\n");
break;
}
}
up->fpstate = FPACTIVE;
return notrap;
}
enum
{
SE_WRITE = 4<<5,
SE_PROT = 2<<2,
};
static void
faultsparc(Ureg *ur)
{
ulong addr;
char buf[ERRMAX];
int read;
ulong tbr, ser;
tbr = (ur->tbr&0xFFF)>>4;
addr = ur->pc; /* assume instr. exception */
read = 1;
if(tbr == 9){ /* data access exception */
addr = getrmmu(SFAR);
ser = getrmmu(SFSR);
if(ser&(SE_WRITE)) /* is SE_PROT needed? */
read = 0;
}
up->dbgreg = ur; /* for remote acid */
spllo();
sprint(buf, "sys: trap: fault %s addr=0x%lux",
read? "read" : "write", addr);
if(up->type == Interp)
disfault(ur,buf);
dumpregs(ur);
panic("fault: %s", buf);
}
static void
faultasync(Ureg *ur)
{
int user;
print("interrupt 15 AFSR %lux AFAR %lux MFSR %lux MFAR %lux\n",
getphys(AFSR), getphys(AFAR), getphys(MFSR), getphys(MFAR));
dumpregs(ur);
/*
* Clear interrupt
*/
putphys(PROCINTCLR, 1<<15);
user = !(ur->psr&PSRPSUPER);
if(user)
pexit("Suicide", 0);
panic("interrupt 15");
}