Jun Sun wrote:
> On Sat, Feb 14, 2004 at 03:17:40AM +0100, Thiemo Seufer wrote:
> > Ralf Baechle wrote:
> > [snip]
> > > Anyway, gcc could load next weeks lucky lottery numbers into the
> > > s-registers after saving them. That'd break save_static but not the
> > > ABI which only promises to restore the old values in s-registers on
> > > return.
> >
> > Ok, it could, but adding such insns to the prologue wouldn't make
> > sense at all, so this is unlikely to happen.
> >
>
> OS people who have been around long enough know "unlikely" things
> always end up happening. :)
[snip]
> sys_sigsuspend(struct pt_regs regs)
> {
> 8008e280: 27bdffc0 addiu $sp,$sp,-64
> 8008e284: afb00030 sw $s0,48($sp)
> sigset_t *uset, saveset, newset;
>
> save_static(®s);
Which is a compiler bug, because it schedules around __asm__ __volatile__,
but not a breakage caused by the prologue.
There's no way to be safe from broken compilers.
Thiemo
