See page 159 of the recent second edition of McKusick's book on the BSD kernel. It's FreeBSD centric, but its the same concepts. On Jan 14, 2015 6:31 PM, "Theo de Raadt" <dera...@cvs.openbsd.org> wrote:
> > at [1], I read something about 'Sigtramp separation' within > > the W^X transition. I only know that this sigtramp-page (?) is > > used to jump back into the kernel when a signal arrives. > > > > My question is, what exactly is this signal trampoline? > > That is not what the slides say. > > > Why do I need it? > > To return from a signal handler. > > > Why was it on the Stack (first page of the virtual memory)? > > Because it was. > > > And why must it be executable / what does the code? > > Because it is code. > > > Thank you for your help. > > You've got access to all this source code. It is documented. > And there are books. There are search engines which can answer > this. > > But the modern way is to ask large mailing lists? > > If you can't study the world around you, you will remain ignorant.
