Re: debian's mips userland on mips64

[Ralf Baechle <ralf@linux-mips.org>]

On Thu, Jan 23, 2003 at 02:05:44PM +1100, Greg Banks wrote:

> Actually 32bit strace on a 64bit kernel is working *most* of the time, so
> there must be a 32bit ptrace syscall which is mostly working.  But...
> 
> 1.  There is a problem with tracing rt_sigaction() where the signal set
>     argument is being misinterpreted either in ptrace or strace.  The
>     result is an application buffer overflow in strace which causes it
>     to lose track of which processes it's tracing.  This may be entirely
>     an strace issue but presumably it doesn't happen on 32bit kernels,
>     so the fix (when Andrew figures it out) may require strace to know
>     whether it's running on a 64bit kernel.

Strace source is pretty evil ...

> 2.  At some point in the future there may well be 64bit executables which
>     we will want to trace with the 32bit strace.  Possibly strace will
>     need some sort of modification to dynamically detect whether the
>     traced child is 64bit or 32bit.
> 
> I'd be very interested to know if anyone's tried running strace on
> a mips64 kernel, in particular strace'ing the scp program.

[...]
ioctl(2, TCGETS, 0x7fff7858)            = -1 EINVAL (Invalid argument)
rt_sigaction(SIGPIPE, {0x10000000, [], 0x4055f4}, {SIG_DFL}, 16) = 0
pipe([0, 0])                            = 3
pipe([268437928, 721805232])            = 5
pipe([720500616, 2147449192])           = 7
close(3)                                = 0
[...]

  Ralf