ref: c1d40df49550393f3afe53fb6e6d500dfa8eb7a8
dir: /sys/src/9/omap/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" #include "arm.h" typedef struct { uintptr ip; Ureg* arg0; char* arg1; char msg[ERRMAX]; Ureg* old; Ureg ureg; } NFrame; /* * Return user to state before notify() */ static void noted(Ureg* cur, uintptr arg0) { NFrame *nf; Ureg *nur; 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; fpunoted(); nf = up->ureg; /* sanity clause */ if(!okaddr((uintptr)nf, sizeof(NFrame), 0)){ qunlock(&up->debug); pprint("bad ureg in noted %#p\n", nf); pexit("Suicide", 0); } /* don't let user change system flags */ nur = &nf->ureg; nur->psr &= PsrMask|PsrDfiq|PsrDirq; nur->psr |= (cur->psr & ~(PsrMask|PsrDfiq|PsrDirq)); memmove(cur, nur, sizeof(Ureg)); switch((int)arg0){ case NCONT: case NRSTR: if(!okaddr(nur->pc, BY2WD, 0) || !okaddr(nur->sp, BY2WD, 0)){ qunlock(&up->debug); pprint("suicide: trap in noted\n"); pexit("Suicide", 0); } up->ureg = nf->old; qunlock(&up->debug); break; case NSAVE: if(!okaddr(nur->pc, BY2WD, 0) || !okaddr(nur->sp, BY2WD, 0)){ qunlock(&up->debug); pprint("suicide: trap in noted\n"); pexit("Suicide", 0); } qunlock(&up->debug); splhi(); nf->arg1 = nf->msg; nf->arg0 = &nf->ureg; nf->ip = 0; cur->sp = (uintptr)nf; cur->r0 = (uintptr)nf->arg0; break; default: up->lastnote->flag = NDebug; /*FALLTHROUGH*/ case NDFLT: qunlock(&up->debug); if(up->lastnote->flag == NDebug) pprint("suicide: %s\n", up->lastnote->msg); pexit(up->lastnote->msg, up->lastnote->flag != NDebug); } } /* * Call user, if necessary, with note. * Pass user the Ureg struct and the note on his stack. */ int notify(Ureg* ureg) { u32int s; uintptr sp; NFrame *nf; char *msg; if(up->procctl) procctl(); if(up->nnote == 0) return 0; fpunotify(ureg); s = spllo(); qlock(&up->debug); msg = popnote(ureg); if(msg == nil){ qunlock(&up->debug); splhi(); return 0; } if(!okaddr((uintptr)up->notify, 1, 0)){ qunlock(&up->debug); pprint("suicide: notify function address %#p\n", up->notify); pexit("Suicide", 0); } sp = ureg->sp - sizeof(NFrame); if(!okaddr(sp, sizeof(NFrame), 1)){ qunlock(&up->debug); pprint("suicide: notify stack address %#p\n", sp); pexit("Suicide", 0); } nf = (void*)sp; memmove(&nf->ureg, ureg, sizeof(Ureg)); nf->old = up->ureg; up->ureg = nf; memmove(nf->msg, msg, ERRMAX); nf->arg1 = nf->msg; nf->arg0 = &nf->ureg; nf->ip = 0; ureg->sp = sp; ureg->pc = (uintptr)up->notify; ureg->r0 = (uintptr)nf->arg0; qunlock(&up->debug); splx(s); return 1; } void syscall(Ureg* ureg) { char *e; u32int s; ulong sp; long ret; int i, scallnr; if(!kenter(ureg)) panic("syscall: from kernel: pc %#lux r14 %#lux psr %#lux", ureg->pc, ureg->r14, ureg->psr); m->syscall++; up->insyscall = 1; up->pc = ureg->pc; if(up->procctl == Proc_tracesyscall){ up->procctl = Proc_stopme; procctl(); } scallnr = ureg->r0; up->scallnr = scallnr; spllo(); sp = ureg->sp; up->nerrlab = 0; ret = -1; if(!waserror()){ if(scallnr >= nsyscall){ pprint("bad sys call number %d pc %#lux\n", scallnr, ureg->pc); postnote(up, 1, "sys: bad sys call", NDebug); error(Ebadarg); } if(sp < (USTKTOP-BY2PG) || sp > (USTKTOP-sizeof(Sargs)-BY2WD)) validaddr(sp, sizeof(Sargs)+BY2WD, 0); up->s = *((Sargs*)(sp+BY2WD)); up->psstate = sysctab[scallnr]; /* iprint("%s: syscall %s\n", up->text, sysctab[scallnr]?sysctab[scallnr]:"huh?"); */ 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; } if(up->nerrlab){ print("bad errstack [%d]: %d extra\n", scallnr, up->nerrlab); for(i = 0; i < NERR; i++) print("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->r0 = ret; if(up->procctl == Proc_tracesyscall){ s = splhi(); up->procctl = Proc_stopme; procctl(); splx(s); } up->insyscall = 0; up->psstate = 0; if(scallnr == NOTED) noted(ureg, *(ulong*)(sp+BY2WD)); 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); } uintptr execregs(uintptr entry, ulong ssize, ulong nargs) { ulong *sp; Ureg *ureg; sp = (ulong*)(USTKTOP - ssize); *--sp = nargs; ureg = up->dbgreg; // memset(ureg, 0, 15*sizeof(ulong)); ureg->r13 = (ulong)sp; ureg->pc = entry; //print("%lud: EXECREGS pc %#ux sp %#ux nargs %ld\n", up->pid, ureg->pc, ureg->r13, nargs); /* * return the address of kernel/user shared data * (e.g. clock stuff) */ return USTKTOP-sizeof(Tos); } void sysprocsetup(Proc* p) { fpusysprocsetup(p); } /* * Craft a return frame which will cause the child to pop out of * the scheduler in user mode with the return register zero. Set * pc to point to a l.s return function. */ void forkchild(Proc *p, Ureg *ureg) { Ureg *cureg; //print("%lud setting up for forking child %lud\n", up->pid, p->pid); p->sched.sp = (ulong)p-sizeof(Ureg); p->sched.pc = (ulong)forkret; cureg = (Ureg*)(p->sched.sp); memmove(cureg, ureg, sizeof(Ureg)); /* syscall returns 0 for child */ cureg->r0 = 0; }