ref: 9efcce402b4c7b16b86bfd612fa35ea0d536da2b
dir: /sys/src/9/bcm/trap.c/
/* * 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" enum { Nvec = 8, /* # of vectors at start of lexception.s */ }; /* * Layout at virtual address KZERO (double mapped at HVECTORS). */ typedef struct Vpage0 { void (*vectors[Nvec])(void); u32int vtable[Nvec]; } Vpage0; 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 irq(Ureg*); extern int notify(Ureg*); /* * set up for exceptions */ void trapinit(void) { Vpage0 *vpage0; intrcpushutdown(); if (m->machno == 0) { /* 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(); l2cacheuwbinv(); } /* 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(); } static char * trapname(int psr) { char *s; s = trapnames[psr & PsrMask]; if(s == nil) s = "unknown trap number in psr"; return s; } /* * 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, ureg->pc, 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)-((char*)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 = kenter(ureg); /* * 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); 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) estack = (uintptr)up; else if((uintptr)&l >= (uintptr)m->stack && (uintptr)&l <= (uintptr)m+MACHSIZE) estack = (uintptr)m+MACHSIZE; else{ if(up != nil) iprint("&up %#p &l %#p\n", up, &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 = (uintptr)&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", (char*)up - KSTACK, up); else iprint("kernel stack: %8.8lux-%8.8lux\n", (ulong)(m+1), (ulong)m+BY2PG); dumplongs("stack", (ulong *)(ureg + 1), 16); delay(2000); dumpstack(); splx(s); }