ref: d5fc608059dee5f65ddfdf3e230bb8d458ccf43f
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 */
}