On 05/14/2014 04:22 PM, Dave Jones wrote:
> On Wed, May 14, 2014 at 12:35:38PM +0100, Markos Chandras wrote:
> > MIPS and IA64 have their syscall tables starting at non-zero
> > offsets so take that into account when executing a sycall
> > otherwise trinity just fails with ENOSYS error messages.
> >
> > Tested on MIPS 32/LE system.
> >
> > Signed-off-by: Markos Chandras <markos.chandras@xxxxxxxxxx>
> > ---
> > syscall.c | 5 +++--
> > 1 file changed, 3 insertions(+), 2 deletions(-)
> >
> > diff --git a/syscall.c b/syscall.c
> > index 968962b..a1ccb6b 100644
> > --- a/syscall.c
> > +++ b/syscall.c
> > @@ -79,6 +79,7 @@ static long syscall32(unsigned int call,
> > static unsigned long do_syscall(int childno, int *errno_saved)
> > {
> > int nr = shm->syscall[childno].nr;
> > + int call = nr + SYSCALL_OFFSET;
> > unsigned long a1, a2, a3, a4, a5, a6;
> > unsigned long ret = 0;
> >
> > @@ -99,9 +100,9 @@ static unsigned long do_syscall(int childno, int *errno_saved)
> > errno = 0;
> >
> > if (shm->syscall[childno].do32bit == FALSE)
> > - ret = syscall(nr, a1, a2, a3, a4, a5, a6);
> > + ret = syscall(call, a1, a2, a3, a4, a5, a6);
> > else
> > - ret = syscall32(nr, a1, a2, a3, a4, a5, a6);
> > + ret = syscall32(call, a1, a2, a3, a4, a5, a6);
> >
> > *errno_saved = errno;
>
> Oops. This was the intention of the code in mkcall() that calls
> do_syscall().
>
> 152 /* Some architectures (IA64/MIPS) start their Linux syscalls
> 153 * At non-zero, and have other ABIs below.
> 154 */
> 155 call += SYSCALL_OFFSET;
>
> Looking at that code closer, it seems that the code around line 193
> will do the wrong thing on MIPS/IA64 because we've done this addition.
>
> I'm wondering if just removing those lines I just quoted would be
> the right thing to do (after applying your patch).
>
> Dave
>
Hi Dave,
Removing these four lines may work but it will break the following:
209 output(1, "%s (%d) returned ENOSYS, marking as
inactive.\n",
210 entry->name, call);
'call' will have the syscall (shm->syscall[childno].nr) number without
the offset which will simply print the wrong syscall number for mips and
ia64.
I am not that familiar with the code yet to be able to tell whether the
'search_syscall_table' or 'deactivate_syscall' functions need the offset
as well or not.
--
markos
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