Re: CVS commit: src/sys/arch/i386/i386

[Manuel Bouyer <bouyer%antioche.eu.org@localhost>]

On Tue, May 05, 2009 at 09:20:02PM +0000, Andrew Doran wrote:
> > I tried the following code instead:
> > IDTVEC(osyscall)
> >         CLI(%eax)               # must be first instruction
> >     pushfl                  # set eflags in trap frame
> >     popl    8(%esp)
> >     orl     $PSL_I,(%esp)   # re-enable ints on return to user
> >     pushl   $7              # size of instruction for restart
> >     jmp     syscall1
> > 
> > but the test binary from the PR segfaults:
> > truc# kdump |less                                                           
> >    
> > 34      0 ktrace   EMUL  "netbsd"
> > 34      0 ktrace   RET   ktrace 0
> > 34      0 ktrace   CALL  execve(0xbf7ffc02,0xbf7feb3c,0xbf7feb44)
> > 34      0 ktrace   NAMI  "./architextIndex"
> > 34      0 architextIndex EMUL  "netbsd"
> > 34      0 architextIndex RET   syscall JUSTRETURN
> > 34      0 architextIndex PSIG  SIGSEGV SIG_DFL: code=SEGV_ACCERR, 
> > addr=0xacb 94, trap=4)
> > 34      0 architextIndex NAMI  "architextIndex.core"
> > 
> > On Xen CLI(%eax) expands to:
> >    movl    CPUVAR(VCPU),%eax ;
> >    movb $1,EVTCHN_UPCALL_MASK(%eax)
> 
> At this point the segment registers won't be set up.

I think xen restored it, at last the one pointing to curcpu. I'll have to
double-check it.

> And %eax contains the
> syscall number.

Ops. We can use another register then

-- 
Manuel Bouyer <bouyer%antioche.eu.org@localhost>
     NetBSD: 26 ans d'experience feront toujours la difference
--