1997/1011/pc/trap.c (diff list | history)

pc/trap.c on 1991/0613
1991/0613		#include "u.h"
1992/0321		#include "../port/lib.h"
1991/0613		#include "mem.h" #include "dat.h" #include "fns.h" #include "io.h"
1991/0703		#include "ureg.h"
1992/0111		#include "../port/error.h"
1991/0613
1991/0720		void noted(Ureg*, ulong);
1997/0327		static void debugbpt(Ureg*, void*); static void fault386(Ureg*, void*); static void syscall(Ureg*, void*);
1991/0731
1997/0327		static Lock irqctllock; static Irqctl *irqctl[256];
1991/0709
1991/0703		void
1997/0327		intrenable(int v, void (*f)(Ureg*, void*), void* a, int tbdf)
1991/0613		{
1997/0327		Irq * irq; Irqctl *ctl;
1991/0614
1997/0327		lock(&irqctllock); if(irqctl[v] == 0){ ctl = xalloc(sizeof(Irqctl)); if(arch->intrenable(v, tbdf, ctl) == -1){ unlock(&irqctllock); /* print("intrenable: didn't find v %d, tbdf 0x%uX\n", v, tbdf); */ xfree(ctl); return; } irqctl[v] = ctl;
1991/0709		}
1997/0327		ctl = irqctl[v]; irq = xalloc(sizeof(Irq)); irq->f = f; irq->a = a; irq->next = ctl->irq; ctl->irq = irq; unlock(&irqctllock);
1991/0703		}
1997/0405		static void nmienable(void) { int x; /* * Hack: should be locked with NVRAM access. */ outb(0x70, 0x80); outb(0x70, 0); x = inb(0x61); outb(0x61, 0x08|x); outb(0x61, x & ~0x08); }
1991/1112		void
1991/0703		trapinit(void) {
1997/0327		int v, pri; ulong vaddr; Segdesc *idt;
1991/0614
1997/0327		idt = (Segdesc*)IDTADDR; vaddr = (ulong)vectortable; for(v = 0; v < 256; v++){ if(v == VectorBPT || v == VectorSYSCALL) pri = 3; else pri = 0; idt[v].d0 = (vaddr & 0xFFFF)|(KESEL<<16); idt[v].d1 = (vaddr & 0xFFFF0000)|SEGP|SEGPL(pri)|SEGIG; vaddr += 6; }
1991/0731
1997/0327		intrenable(VectorBPT, debugbpt, 0, BUSUNKNOWN); intrenable(VectorPF, fault386, 0, BUSUNKNOWN); intrenable(VectorSYSCALL, syscall, 0, BUSUNKNOWN);
1997/0405		nmienable();
1991/0703		}
1994/0722		char *excname[] = { [0] "divide error", [1] "debug exception",
1997/0327		[2] "nonmaskable interrupt",
1994/0722		[3] "breakpoint", [4] "overflow", [5] "bounds check", [6] "invalid opcode", [7] "coprocessor not available", [8] "double fault",
1997/0327		[9] "coprocessor segment overrun",
1994/0722		[10] "invalid TSS", [11] "segment not present", [12] "stack exception", [13] "general protection violation", [14] "page fault", [15] "15 (reserved)", [16] "coprocessor error",
1994/1029		[17] "alignment check",
1997/0327		[18] "machine check",
1991/1113		};
1997/0327		static int nspuriousintr;
1994/1029
1991/0614		/*
1993/1124		* All traps come here. It is slower to have all traps call trap() rather than
1993/1115		* directly vectoring the handler. However, this avoids a lot of code duplication
1994/0715		* and possible bugs. trap is called splhi().
1991/0614		*/
1991/0710		void
1997/0327		trap(Ureg* ureg)
1991/0614		{
1991/1112		int v, user;
1991/1113		char buf[ERRLEN];
1997/0327		Irqctl *ctl; Irq *irq;
1991/0703
1997/0327		user = (ureg->cs & 0xFFFF) == UESEL;
1991/1112		if(user)
1997/0327		up->dbgreg = ureg;
1991/1112
1997/0327		v = ureg->trap; if(ctl = irqctl[v]){ if(ctl->isintr) m->intr++; if(ctl->isr) ctl->isr(v);
1991/1113
1997/0327		for(irq = ctl->irq; irq; irq = irq->next) irq->f(ureg, irq->a);
1993/0224
1997/0327		if(ctl->eoi) ctl->eoi(v);
1991/0731		}
1997/0327		else if(v <= 16 && user){ spllo(); sprint(buf, "sys: trap: %s", excname[v]); postnote(up, 1, buf, NDebug); } else if(v >= VectorPIC && v <= MaxVectorPIC){ /* * An unknown interrupt. * Check for a default IRQ7. This can happen when * the IRQ input goes away before the acknowledge. * In this case, a 'default IRQ7' is generated, but * the corresponding bit in the ISR isn't set. * In fact, just ignore all such interrupts. */ if(nspuriousintr < 2) print("spurious interrupt %d\n", v-VectorPIC); nspuriousintr++; return; } else{
1997/0405		if(v == 2){ if(m->machno != 0) for(;;); nmienable(); }
1997/0327		dumpregs(ureg); if(v < nelem(excname)) panic("%s", excname[v]); panic("unknown trap/intr: %d\n", v); }
1991/0801
1994/0715		/* * check user since syscall does its own notifying */
1993/0915		splhi();
1997/0327		if(v != VectorSYSCALL && user && (up->procctl || up->nnote)) notify(ureg);
1991/0806		} /*
1991/0718		* dump registers */ void
1997/0327		dumpregs2(Ureg* ureg)
1991/0718		{
1997/0327		ureg->cs &= 0xFFFF; ureg->ds &= 0xFFFF; ureg->es &= 0xFFFF; ureg->fs &= 0xFFFF; ureg->gs &= 0xFFFF;
1993/1115
1993/0915		if(up)
1997/0327		print("cpu%d: registers for %s %d\n", m->machno, up->text, up->pid);
1991/0718		else
1997/0327		print("cpu%d: registers for kernel\n", m->machno); print("FLAGS=%luX TRAP=%luX ECODE=%luX PC=%luX", ureg->flags, ureg->trap, ureg->ecode, ureg->pc); print(" SS=%4.4luX USP=%luX\n", ureg->ss & 0xFFFF, ureg->usp); print(" AX %8.8luX BX %8.8luX CX %8.8luX DX %8.8luX\n", ureg->ax, ureg->bx, ureg->cx, ureg->dx); print(" SI %8.8luX DI %8.8luX BP %8.8luX\n", ureg->si, ureg->di, ureg->bp); print(" CS %4.4uX DS %4.4uX ES %4.4uX FS %4.4uX GS %4.4uX\n", ureg->cs, ureg->ds, ureg->es, ureg->fs, ureg->gs);
1991/0718		}
1991/0720		void
1997/0327		dumpregs(Ureg* ureg)
1993/0915		{
1994/0813		extern ulong etext;
1997/0327		ulong mca[2], mct[2];
1993/1113
1997/0327		dumpregs2(ureg);
1994/0813
1997/0327		/* * Processor control registers. * If machine check exception, time stamp counter, page size extensions or * enhanced virtual 8086 mode extensions are supported, there is a CR4. * If there is a CR4 and machine check extensions, read the machine check * address and machine check type registers if RDMSR supported. */ print(" CR0 %8.8lux CR2 %8.8lux CR3 %8.8lux", getcr0(), getcr2(), getcr3()); if(m->cpuiddx & 0x9A){ print(" CR4 %8.8luX", getcr4()); if((m->cpuiddx & 0xA0) == 0xA0){ rdmsr(0x00, &mca[1], &mca[0]); rdmsr(0x01, &mct[1], &mct[0]); print("\n MCA %8.8luX:%8.8luX MCT %8.8luX", mca[1], mca[0], mct[0]); } } print("\n ur %luX up %luX\n", ureg, up);
1993/0915		} void
1991/0720		dumpstack(void) {
1992/0804		ulong l, v, i;
1997/0327		uchar *p;
1992/0804		extern ulong etext;
1993/0915		if(up == 0)
1992/0804		return; i = 0;
1994/0816		for(l=(ulong)&l; l<(ulong)(up->kstack+KSTACK); l+=4){
1992/0804		v = *(ulong*)l; if(KTZERO < v && v < (ulong)&etext){
1997/0327		p = (uchar*)v; if(*(p-5) == 0xE8){ print("%lux ", p-5); i++; }
1992/0804		}
1993/1113		if(i == 8){
1992/0804		i = 0; print("\n"); } }
1991/0720		}
1997/0327		static void debugbpt(Ureg* ureg, void*) { char buf[ERRLEN]; if(up == 0) panic("kernel bpt"); /* restore pc to instruction that caused the trap */ ureg->pc--; sprint(buf, "sys: breakpoint"); postnote(up, 1, buf, NDebug); } static void fault386(Ureg* ureg, void*) { ulong addr; int read, user, n, insyscall; char buf[ERRLEN]; insyscall = up->insyscall; up->insyscall = 1; addr = getcr2(); read = !(ureg->ecode & 2); user = (ureg->cs&0xffff) == UESEL; spllo(); n = fault(addr, read); if(n < 0){ if(user){ sprint(buf, "sys: trap: fault %s addr=0x%lux", read? "read" : "write", addr); postnote(up, 1, buf, NDebug); return; }
1997/1011		if(mmukmapsync(addr) == 0){ dumpregs(ureg); panic("fault: 0x%lux\n", addr); }
1997/0327		} up->insyscall = insyscall; }
1991/0718		/*
1991/0710		* system calls */
1991/0731		#include "../port/systab.h"
1991/0720
1992/0103		/*
1994/0715		* syscall is called splhi()
1992/0103		*/
1997/0327		static void syscall(Ureg* ureg, void*)
1991/0710		{
1991/0720		ulong sp; long ret; int i;
1997/0327		m->syscall++;
1993/0915		up->insyscall = 1;
1997/0327		up->pc = ureg->pc; up->dbgreg = ureg;
1993/1225
1997/0327		if((ureg->cs)&0xffff == KESEL)
1991/0720		panic("recursive system call");
1991/0718
1997/0327		up->scallnr = ureg->ax;
1993/0915		if(up->scallnr == RFORK && up->fpstate == FPactive){
1992/0805		/* * so that the child starts out with the
1994/0715		* same registers as the parent. * this must be atomic relative to this CPU, hence * the spl's.
1992/0805		*/
1993/0915		if(up->fpstate == FPactive){ fpsave(&up->fpsave); up->fpstate = FPinactive;
1992/0805		} }
1994/0715		spllo();
1997/0327		sp = ureg->usp;
1993/0915		up->nerrlab = 0;
1991/0720		ret = -1; if(!waserror()){
1994/0407		if(up->scallnr >= nsyscall){
1997/0327		pprint("bad sys call number %d pc %lux\n", up->scallnr, ureg->pc);
1993/1013		postnote(up, 1, "sys: bad sys call", NDebug);
1991/0720		error(Ebadarg); }
1992/0625
1991/0720		if(sp<(USTKTOP-BY2PG) || sp>(USTKTOP-(1+MAXSYSARG)*BY2WD)) validaddr(sp, (1+MAXSYSARG)*BY2WD, 0);
1992/0625
1993/0915		up->s = *((Sargs*)(sp+1*BY2WD)); up->psstate = sysctab[up->scallnr];
1992/0625
1997/0327		ret = systab[up->scallnr](up->s.args);
1991/0720		poperror(); }
1993/0915		if(up->nerrlab){ print("bad errstack [%d]: %d extra\n", up->scallnr, up->nerrlab);
1991/0720		for(i = 0; i < NERR; i++)
1993/0915		print("sp=%lux pc=%lux\n", up->errlab[i].sp, up->errlab[i].pc);
1991/0720		panic("error stack"); }
1991/1114
1993/0915		up->insyscall = 0; up->psstate = 0;
1992/0609		/* * Put return value in frame. On the safari 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. */
1997/0327		ureg->ax = ret;
1992/0609
1993/0915		if(up->scallnr == NOTED)
1997/0327		noted(ureg, *(ulong*)(sp+BY2WD));
1995/0105		splhi();
1991/1114
1993/0915		if(up->scallnr!=RFORK && (up->procctl || up->nnote))
1997/0327		notify(ureg);
1995/0115
1991/0710		}
1991/0720		/* * Call user, if necessary, with note. * Pass user the Ureg struct and the note on his stack. */
1992/0108		int
1997/0327		notify(Ureg* ureg)
1991/0710		{
1995/0202		int l;
1991/1114		ulong s, sp;
1991/1218		Note *n;
1991/0720
1993/0915		if(up->procctl)
1993/1013		procctl(up);
1993/0915		if(up->nnote == 0)
1992/0108		return 0;
1991/1114		s = spllo();
1993/0915		qlock(&up->debug); up->notepending = 0; n = &up->note[0];
1991/1218		if(strncmp(n->msg, "sys:", 4) == 0){ l = strlen(n->msg); if(l > ERRLEN-15) /* " pc=0x12345678\0" */ l = ERRLEN-15;
1997/0327		sprint(n->msg+l, " pc=0x%.8lux", ureg->pc);
1991/1218		}
1995/0202
1993/0915		if(n->flag!=NUser && (up->notified || up->notify==0)){
1992/0714		if(n->flag == NDebug)
1991/1218		pprint("suicide: %s\n", n->msg);
1996/0626		qunlock(&up->debug);
1991/1218		pexit(n->msg, n->flag!=NDebug);
1991/0720		}
1995/0202		if(up->notified) { qunlock(&up->debug); splhi(); return 0;
1991/0720		}
1995/0202		if(!up->notify){ qunlock(&up->debug); pexit(n->msg, n->flag!=NDebug); }
1997/0327		sp = ureg->usp;
1995/0202		sp -= sizeof(Ureg); if(!okaddr((ulong)up->notify, 1, 0)
1995/02021		|| !okaddr(sp-ERRLEN-4*BY2WD, sizeof(Ureg)+ERRLEN+4*BY2WD, 1)){
1995/0202		pprint("suicide: bad address in notify\n"); qunlock(&up->debug); pexit("Suicide", 0); } up->ureg = (void*)sp;
1997/0327		memmove((Ureg*)sp, ureg, sizeof(Ureg));
1995/0202		*(Ureg**)(sp-BY2WD) = up->ureg; /* word under Ureg is old up->ureg */ up->ureg = (void*)sp; sp -= BY2WD+ERRLEN; memmove((char*)sp, up->note[0].msg, ERRLEN); 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 */
1997/0327		ureg->usp = sp; ureg->pc = (ulong)up->notify;
1995/0202		up->notified = 1; up->nnote--; memmove(&up->lastnote, &up->note[0], sizeof(Note)); memmove(&up->note[0], &up->note[1], up->nnote*sizeof(Note));
1993/0915		qunlock(&up->debug);
1991/1114		splx(s);
1995/0202		return 1;
1991/0710		}
1991/0720		/* * Return user to state before notify() */
1991/0710		void
1997/0327		noted(Ureg* ureg, ulong arg0)
1991/0710		{
1997/0327		Ureg *nureg;
1995/0202		ulong oureg, sp;
1991/0720
1993/0915		qlock(&up->debug);
1995/0202		if(arg0!=NRSTR && !up->notified) {
1993/0915		qunlock(&up->debug);
1994/0513		pprint("call to noted() when not notified\n");
1995/0105		pexit("Suicide", 0);
1991/0720		}
1993/0915		up->notified = 0;
1994/0513
1997/0327		nureg = up->ureg; /* pointer to user returned Ureg struct */
1995/0202		/* sanity clause */
1997/0327		oureg = (ulong)nureg;
1995/02021		if(!okaddr((ulong)oureg-BY2WD, BY2WD+sizeof(Ureg), 0)){
1997/0520		pprint("bad ureg in noted or call to noted when not notified\n");
1994/0513		qunlock(&up->debug);
1995/0202		pexit("Suicide", 0);
1994/0513		}
1997/0520		/* * Check the segment selectors are all valid, otherwise * a fault will be taken on attempting to return to the * user process.
1997/1003		* Take care with the comparisons as different processor * generations push segment descriptors in different ways.
1997/0520		*/
1997/1003		if((nureg->cs & 0xFFFF) != UESEL || (nureg->ss & 0xFFFF) != UDSEL || (nureg->ds & 0xFFFF) != UDSEL || (nureg->es & 0xFFFF) != UDSEL || (nureg->fs & 0xFFFF) != UDSEL || (nureg->gs & 0xFFFF) != UDSEL){ pprint("bad segment selector in noted\n");
1997/0520		qunlock(&up->debug); pexit("Suicide", 0); }
1995/0202		/* don't let user change system flags */
1997/0327		nureg->flags = (ureg->flags & ~0xCD5) | (nureg->flags & 0xCD5);
1995/0202
1997/0327		memmove(ureg, nureg, sizeof(Ureg));
1995/0105
1991/0720		switch(arg0){ case NCONT:
1995/0202		case NRSTR:
1997/0327		if(!okaddr(nureg->pc, 1, 0) || !okaddr(nureg->usp, BY2WD, 0)){
1991/0814		pprint("suicide: trap in noted\n");
1995/0202		qunlock(&up->debug);
1994/0513		pexit("Suicide", 0);
1991/0814		}
1995/0202		up->ureg = (Ureg*)(*(ulong*)(oureg-BY2WD)); qunlock(&up->debug);
1995/0105		break;
1991/0720
1995/0202		case NSAVE:
1997/0327		if(!okaddr(nureg->pc, BY2WD, 0) || !okaddr(nureg->usp, BY2WD, 0)){
1995/0202		pprint("suicide: trap in noted\n"); qunlock(&up->debug); pexit("Suicide", 0); } qunlock(&up->debug); sp = oureg-4*BY2WD-ERRLEN; splhi();
1997/0327		ureg->sp = sp;
1995/0202		((ulong*)sp)[1] = oureg; /* arg 1 0(FP) is ureg* */ ((ulong*)sp)[0] = 0; /* arg 0 is pc */ break;
1991/0720		default: pprint("unknown noted arg 0x%lux\n", arg0);
1993/0915		up->lastnote.flag = NDebug;
1991/0720		/* fall through */ case NDFLT:
1993/0915		if(up->lastnote.flag == NDebug) pprint("suicide: %s\n", up->lastnote.msg);
1995/0202		qunlock(&up->debug);
1993/0915		pexit(up->lastnote.msg, up->lastnote.flag!=NDebug);
1991/0720		}
1991/1112		}
1993/1113		long execregs(ulong entry, ulong ssize, ulong nargs) { ulong *sp;
1997/0327		Ureg *ureg;
1993/1113		sp = (ulong*)(USTKTOP - ssize); *--sp = nargs;
1997/0327		ureg = up->dbgreg; ureg->usp = (ulong)sp; ureg->pc = entry;
1994/0513		return USTKTOP-BY2WD; /* address of user-level clock */
1993/1113		} ulong userpc(void) {
1997/0327		Ureg *ureg;
1993/1113
1997/0327		ureg = (Ureg*)up->dbgreg; return ureg->pc;
1993/1113		}
1991/1112		/* This routine must save the values of registers the user is not permitted to write
1997/0327		* from devproc and then restore the saved values before returning
1991/1112		*/ void
1997/0327		setregisters(Ureg* ureg, char* pureg, char* uva, int n)
1991/1112		{ ulong flags; ulong cs; ulong ss;
1997/0327		flags = ureg->flags; cs = ureg->cs; ss = ureg->ss;
1991/1112		memmove(pureg, uva, n);
1997/0327		ureg->flags = (ureg->flags & 0x00FF) | (flags & 0xFF00); ureg->cs = cs; ureg->ss = ss;
1993/1113		} static void linkproc(void) { spllo();
1997/0327		up->kpfun(up->kparg);
1993/1113		} void
1997/0327		kprocchild(Proc* p, void (*func)(void*), void* arg)
1993/1113		{ p->sched.pc = (ulong)linkproc; p->sched.sp = (ulong)p->kstack+KSTACK; p->kpfun = func; p->kparg = arg; } void
1997/0327		forkchild(Proc *p, Ureg *ureg)
1993/1113		{
1997/0327		Ureg *cureg;
1993/1113		/*
1997/0327		* Add 2*BY2WD to the stack to account for
1993/1113		* - the return PC * - trap's argument (ur) */ p->sched.sp = (ulong)p->kstack+KSTACK-(sizeof(Ureg)+2*BY2WD); p->sched.pc = (ulong)forkret;
1997/0327		cureg = (Ureg*)(p->sched.sp+2*BY2WD); memmove(cureg, ureg, sizeof(Ureg)); cureg->ax = 0; /* return value of syscall in child */
1993/1113
1997/0327		/* Things from bottom of syscall which were never executed */
1993/1113		p->psstate = 0; p->insyscall = 0;
1991/0614		}
1993/1022		/* Give enough context in the ureg to produce a kernel stack for * a sleeping process */ void
1997/0327		setkernur(Ureg* ureg, Proc* p)
1993/1022		{
1997/0327		ureg->pc = p->sched.pc; ureg->sp = p->sched.sp+4;
1993/1022		}
1995/1024		ulong dbgpc(Proc *p) {
1997/0327		Ureg *ureg;
1995/1024
1997/0327		ureg = p->dbgreg; if(ureg == 0)
1995/1024		return 0;
1997/0327		return ureg->pc;
1995/1024		}