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- /*
- * traps, exceptions, interrupts, system calls.
- */
- #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 "arm.h"
- #define INTREGS (VIRTIO+0xB200)
- typedef struct Intregs Intregs;
- typedef struct Vctl Vctl;
- enum {
- Debug = 0,
- Nvec = 8, /* # of vectors at start of lexception.s */
- Fiqenable = 1<<7,
- };
- /*
- * Layout at virtual address KZERO (double mapped at HVECTORS).
- */
- typedef struct Vpage0 {
- void (*vectors[Nvec])(void);
- u32int vtable[Nvec];
- } Vpage0;
- /*
- * interrupt control registers
- */
- struct Intregs {
- u32int ARMpending;
- u32int GPUpending[2];
- u32int FIQctl;
- u32int GPUenable[2];
- u32int ARMenable;
- u32int GPUdisable[2];
- u32int ARMdisable;
- };
- struct Vctl {
- Vctl *next;
- int irq;
- u32int *reg;
- u32int mask;
- void (*f)(Ureg*, void*);
- void *a;
- };
- static Vctl *vctl, *vfiq;
- static char *trapnames[PsrMask+1] = {
- [ PsrMusr ] "user mode",
- [ PsrMfiq ] "fiq interrupt",
- [ PsrMirq ] "irq interrupt",
- [ PsrMsvc ] "svc/swi exception",
- [ PsrMabt ] "prefetch abort/data abort",
- [ PsrMabt+1 ] "data abort",
- [ PsrMund ] "undefined instruction",
- [ PsrMsys ] "sys trap",
- };
- extern int notify(Ureg*);
- /*
- * set up for exceptions
- */
- void
- trapinit(void)
- {
- Vpage0 *vpage0;
- /* disable everything */
- intrsoff();
- /* set up the exception vectors */
- vpage0 = (Vpage0*)HVECTORS;
- memmove(vpage0->vectors, vectors, sizeof(vpage0->vectors));
- memmove(vpage0->vtable, vtable, sizeof(vpage0->vtable));
- cacheuwbinv();
- /* set up the stacks for the interrupt modes */
- setr13(PsrMfiq, (u32int*)(FIQSTKTOP));
- setr13(PsrMirq, m->sirq);
- setr13(PsrMabt, m->sabt);
- setr13(PsrMund, m->sund);
- setr13(PsrMsys, m->ssys);
- coherence();
- }
- void
- intrsoff(void)
- {
- Intregs *ip;
- int disable;
- ip = (Intregs*)INTREGS;
- disable = ~0;
- ip->GPUdisable[0] = disable;
- ip->GPUdisable[1] = disable;
- ip->ARMdisable = disable;
- ip->FIQctl = 0;
- }
- /*
- * called by trap to handle irq interrupts.
- * returns true iff a clock interrupt, thus maybe reschedule.
- */
- static int
- irq(Ureg* ureg)
- {
- Vctl *v;
- int clockintr;
- clockintr = 0;
- for(v = vctl; v; v = v->next)
- if(*v->reg & v->mask){
- coherence();
- v->f(ureg, v->a);
- coherence();
- if(v->irq == IRQclock)
- clockintr = 1;
- }
- return clockintr;
- }
- /*
- * called direct from lexception.s to handle fiq interrupt.
- */
- void
- fiq(Ureg *ureg)
- {
- Vctl *v;
- v = vfiq;
- if(v == nil)
- panic("unexpected item in bagging area");
- m->intr++;
- ureg->pc -= 4;
- coherence();
- v->f(ureg, v->a);
- coherence();
- }
- void
- irqenable(int irq, void (*f)(Ureg*, void*), void* a)
- {
- Vctl *v;
- Intregs *ip;
- u32int *enable;
- ip = (Intregs*)INTREGS;
- v = (Vctl*)malloc(sizeof(Vctl));
- if(v == nil)
- panic("irqenable: no mem");
- v->irq = irq;
- if(irq >= IRQbasic){
- enable = &ip->ARMenable;
- v->reg = &ip->ARMpending;
- v->mask = 1 << (irq - IRQbasic);
- }else{
- enable = &ip->GPUenable[irq/32];
- v->reg = &ip->GPUpending[irq/32];
- v->mask = 1 << (irq % 32);
- }
- v->f = f;
- v->a = a;
- if(irq == IRQfiq){
- assert((ip->FIQctl & Fiqenable) == 0);
- assert((*enable & v->mask) == 0);
- vfiq = v;
- ip->FIQctl = Fiqenable | irq;
- }else{
- v->next = vctl;
- vctl = v;
- *enable = v->mask;
- }
- }
- static char *
- trapname(int psr)
- {
- char *s;
- s = trapnames[psr & PsrMask];
- if(s == nil)
- s = "unknown trap number in psr";
- return s;
- }
- /* this is quite helpful during mmu and cache debugging */
- static void
- ckfaultstuck(uintptr va)
- {
- static int cnt, lastpid;
- static uintptr lastva;
- if (va == lastva && up->pid == lastpid) {
- ++cnt;
- if (cnt >= 2)
- /* fault() isn't fixing the underlying cause */
- panic("fault: %d consecutive faults for va %#p",
- cnt+1, va);
- } else {
- cnt = 0;
- lastva = va;
- lastpid = up->pid;
- }
- }
- /*
- * 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;
- if (Debug)
- ckfaultstuck(va);
- 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;
- }
- /*
- * 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) and fiq
- */
- void
- trap(Ureg *ureg)
- {
- int clockintr, user, x, rv, rem;
- ulong inst, fsr;
- uintptr va;
- char buf[ERRMAX];
- assert(!islo());
- if(up != nil)
- rem = ((char*)ureg)-up->kstack;
- else
- rem = ((char*)ureg)-((char*)m+sizeof(Mach));
- if(rem < 256) {
- 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:
- clockintr = irq(ureg);
- m->intr++;
- break;
- case PsrMabt: /* prefetch fault */
- 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 */
- 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;
- 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)
- postnote(up, 1, "sys: breakpoint", NDebug);
- else{
- /* look for floating point instructions to interpret */
- rv = fpuemu(ureg);
- if(rv == 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);
- panic("undefined instruction");
- }
- break;
- }
- splhi();
- /* delaysched set because we held a lock or because our quantum ended */
- if(up && up->delaysched && clockintr){
- sched(); /* can cause more traps */
- splhi();
- }
- if(user){
- if(up->procctl || up->nnote)
- notify(ureg);
- kexit(ureg);
- }
- }
- int
- isvalidaddr(void *v)
- {
- return (uintptr)v >= KZERO;
- }
- static void
- dumplongs(char *msg, ulong *v, int n)
- {
- int i, l;
- l = 0;
- iprint("%s at %.8p: ", msg, v);
- for(i=0; i<n; i++){
- if(l >= 4){
- iprint("\n %.8p: ", v);
- l = 0;
- }
- if(isvalidaddr(v)){
- iprint(" %.8lux", *v++);
- l++;
- }else{
- iprint(" invalid");
- break;
- }
- }
- iprint("\n");
- }
- static void
- dumpstackwithureg(Ureg *ureg)
- {
- uintptr l, i, v, estack;
- u32int *p;
- char *s;
- if((s = getconf("*nodumpstack")) != nil && strcmp(s, "0") != 0){
- iprint("dumpstack disabled\n");
- return;
- }
- iprint("ktrace /kernel/path %#.8lux %#.8lux %#.8lux # pc, sp, link\n",
- ureg->pc, ureg->sp, ureg->r14);
- delay(2000);
- i = 0;
- if(up != nil && (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{
- if(up != nil)
- iprint("&up->kstack %#p &l %#p\n", up->kstack, &l);
- else
- iprint("&m %#p &l %#p\n", m, &l);
- return;
- }
- for(l = (uintptr)&l; l < estack; l += sizeof(uintptr)){
- v = *(uintptr*)l;
- if(KTZERO < v && v < (uintptr)etext && !(v & 3)){
- v -= sizeof(u32int); /* back up an instr */
- p = (u32int*)v;
- if((*p & 0x0f000000) == 0x0b000000){ /* BL instr? */
- iprint("%#8.8lux=%#8.8lux ", l, v);
- i++;
- }
- }
- if(i == 4){
- i = 0;
- iprint("\n");
- }
- }
- if(i)
- iprint("\n");
- }
- /*
- * 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);
- }
- void
- dumpstack(void)
- {
- callwithureg(dumpstackwithureg);
- }
- void
- dumpregs(Ureg* ureg)
- {
- int s;
- if (ureg == nil) {
- iprint("trap: no user process\n");
- return;
- }
- s = splhi();
- iprint("trap: %s", trapname(ureg->type));
- if(ureg != nil && (ureg->psr & PsrMask) != PsrMsvc)
- iprint(" in %s", trapname(ureg->psr));
- iprint("\n");
- iprint("psr %8.8lux type %2.2lux pc %8.8lux link %8.8lux\n",
- ureg->psr, ureg->type, ureg->pc, ureg->link);
- iprint("R14 %8.8lux R13 %8.8lux R12 %8.8lux R11 %8.8lux R10 %8.8lux\n",
- ureg->r14, ureg->r13, ureg->r12, ureg->r11, ureg->r10);
- iprint("R9 %8.8lux R8 %8.8lux R7 %8.8lux R6 %8.8lux R5 %8.8lux\n",
- ureg->r9, ureg->r8, ureg->r7, ureg->r6, ureg->r5);
- iprint("R4 %8.8lux R3 %8.8lux R2 %8.8lux R1 %8.8lux R0 %8.8lux\n",
- ureg->r4, ureg->r3, ureg->r2, ureg->r1, ureg->r0);
- iprint("stack is at %#p\n", ureg);
- iprint("pc %#lux link %#lux\n", ureg->pc, ureg->link);
- if(up)
- iprint("user stack: %#p-%#p\n", up->kstack, up->kstack+KSTACK-4);
- else
- iprint("kernel stack: %8.8lux-%8.8lux\n",
- (ulong)(m+1), (ulong)m+BY2PG-4);
- dumplongs("stack", (ulong *)(ureg + 1), 16);
- delay(2000);
- dumpstack();
- splx(s);
- }
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