mips64 sigaction changes

[Alexandre Oliva]

On Mar 14, 2003, Daniel Jacobowitz <drow@mvista.com> wrote:

> Well, I'd rather not.  If you follow linux-mips, Ralf has been talking
> about removing sa_restorer while there are still no uses of it.

My understanding is that he's not doing it for rt signals.  Or maybe
he's just not dropping rt_sigreturn like it seemed like he planned to,
and getting the kernel to set up the restorer in the stack (which is
bad, since it involves flushing instruction caches or so).  Anyway,
it's not like we're exporting sa_restorer, we're just using this
feature like we must to ensure that, if the kernel does require
sa_restorer, we do the right thing.  If it doesn't use sa_restorer,
it's ok, we'll still work, and then we can drop this field at some
point.

>> +/* NOTE: Please think twice before making any changes to the bits of
>> +   code below.  GDB needs some intimate knowledge about it to
>> +   recognize them as signal trampolines, and make backtraces through
>> +   signal handlers work right.  Important are both the names
>> +   (__restore_rt) and the exact instruction sequence.
>> +   If you ever feel the need to make any changes, please notify the
>> +   appropriate GDB maintainer.  */

> This comment's also inappropriate.  GDB won't handle __restore or
> __restore_rt at all.

It should.  Otherwise, how can it get a stack trace from within a
signal handler?

-- 
Alexandre Oliva   Enjoy Guarana', see http://www.ic.unicamp.br/~oliva/
Red Hat GCC Developer                 aoliva@{redhat.com, gcc.gnu.org}
CS PhD student at IC-Unicamp        oliva@{lsd.ic.unicamp.br, gnu.org}
Free Software Evangelist                Professional serial bug killer