ref: 220dfb87f561f73ec1d154e08511332a660d1119
dir: /sys/src/9/mt7688/syscall.c/
#include "u.h" #include "../port/lib.h" #include "mem.h" #include "dat.h" #include "fns.h" #include "../port/error.h" #include "../port/systab.h" #include "tos.h" #include "ureg.h" FPsave initfp; /* * called directly from assembler, not via trap() */ void syscall(Ureg* ureg) { char *e; u32int s; ulong sp; long ret; int i; vlong startns, stopns; ulong scallnr; if(!kenter(ureg)) panic("syscall from kernel"); m->syscall++; up->insyscall = 1; up->pc = ureg->pc; scallnr = ureg->r1; up->scallnr = ureg->r1; spllo(); sp = ureg->sp; up->nerrlab = 0; ret = -1; if(!waserror()){ if(sp < (USTKTOP-BY2PG) || sp > (USTKTOP-sizeof(Sargs))) validaddr(sp, sizeof(Sargs), 0); up->s = *((Sargs*)(sp)); /* spim's libc is different to mips ... */ if(up->procctl == Proc_tracesyscall){ syscallfmt(scallnr, ureg->pc, (va_list)up->s.args); s = splhi(); up->procctl = Proc_stopme; procctl(); splx(s); startns = todget(nil); } if(scallnr >= nsyscall || systab[scallnr] == nil){ postnote(up, 1, "sys: bad sys call", NDebug); error(Ebadarg); } 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; // iprint("[%lud %s] syscall %lud: %s\n",up->pid, up->text, scallnr, up->errstr); } if(up->nerrlab){ iprint("bad errstack [%lud]: %d extra\n", scallnr, up->nerrlab); for(i = 0; i < NERR; i++) iprint("sp=%#p pc=%#p\n", up->errlab[i].sp, up->errlab[i].pc); panic("error stack"); } /* * Put return value in frame. On the x86 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. */ ureg->pc += 4; ureg->r1 = ret; if(up->procctl == Proc_tracesyscall){ stopns = todget(nil); sysretfmt(scallnr, (va_list)up->s.args, ret, startns, stopns); s = splhi(); up->procctl = Proc_stopme; procctl(); splx(s); } up->insyscall = 0; up->psstate = 0; if(scallnr == NOTED) noted(ureg, *((ulong*)up->s.args)); splhi(); if(scallnr != RFORK && (up->procctl || up->nnote)) notify(ureg); /* if we delayed sched because we held a lock, sched now */ if(up->delaysched){ sched(); splhi(); } kexit(ureg); /* restore EXL in status */ setstatus(getstatus() | EXL); } int notify(Ureg *ur) { int s; ulong sp; char *msg; if(up->procctl) procctl(); if(up->nnote == 0) return 0; s = spllo(); qlock(&up->debug); up->fpstate |= FPillegal; msg = popnote(ur); if(msg == nil){ qunlock(&up->debug); splx(s); return 0; } sp = ur->usp - sizeof(Ureg) - BY2WD; /* spim libc */ if(!okaddr((ulong)up->notify, BY2WD, 0) || !okaddr(sp-ERRMAX-4*BY2WD, sizeof(Ureg)+ERRMAX+4*BY2WD, 1)) { iprint("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, 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; 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); } } void forkchild(Proc *p, Ureg *ur) { Ureg *cur; // iprint("%lud setting up for forking child %lud\n", up->pid, p->pid); p->sched.sp = (ulong)p - UREGSIZE; p->sched.pc = (ulong)forkret; cur = (Ureg*)(p->sched.sp+2*BY2WD); memmove(cur, ur, sizeof(Ureg)); cur->r1 = 0; cur->pc += 4; } /* 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 */ // iprint("%lud: %s EXECREGS pc %#luX sp %#luX nargs %ld", up->pid, up->text, ur->pc, ur->usp, nargs); // delay(20); return USTKTOP-sizeof(Tos); /* address of kernel/user shared data */ }