Re: Question about signal syscalls !

["Franck Bui-Huu" <vagabon.xyz@xxxxxxxxx>]

David Daney wrote:
> sys_sigreturn does not return to the caller in the conventional sense.

I expect you're talking about this bite of code taken from _sys_sigreturn():

       /*
        * Don't let your children do this ...
        */
       __asm__ __volatile__(
               "move\t$29, %0\n\t"
               "j\tsyscall_exit"
               :/* no outputs */
               :"r" (&regs));

> The entire user context (i.e. the value of *all* registers) is replaced
> with the values stored in the sigcontext structure on the caller's
> stack.  If all registers are being restored from the sigcontext, then
> there is no need to save the current values of the registers, because
> they will never be used.

But I don't see where _all_ registers are saved. Only static registers
are saved by save_static_function() right before calling
_sys_sigreturn() and I agree I don't why we need to save those.

And now I'm starting to think that we don't need to save static regs in
setup_sigcontext() either...

--
              Franck