https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66960
--- Comment #17 from Goswin von Brederlow <goswin-v-b at web dot de> ---
(In reply to H.J. Lu from comment #16)
> (In reply to Goswin von Brederlow from comment #15)
>
> > > No. We only do it for data pushed onto stack by CPU.
> >
> > I was thinking of something like:
> >
> > __attribute__ ((interrupt("save_regs")))
> > void
> > f (struct interrupt_frame *frame, uword_t error_code, struct regs regs)
> > {
> > kprintf("user SP = %#016x\n", regs.sp);
> > }
>
> It is an interesting idea. But frame and err_code are created by caller,
> which is CPU, not by callee. You want to not only save all original
> registers of interrupted process, but also make them available to interrupt
> handler. This won't be supported without significant changes in
> infrastructure.
Is it a significant change?
On a normal function gcc creates a stackframe and pushes callee saved registers
that it later uses onto the stack. I'm suggesting doing much the same with 2
small changes:
1) push all registers unconditionally
2) make the address where the registers got pushed to known to the function
