What exactly is sigtramp?

2015-01-14 Thread Stefan Berger
hello, 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? Why do I need it? Why was it on the

Re: What exactly is sigtramp?

2015-01-14 Thread Richard Thornton
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

Re: What exactly is sigtramp?

2015-01-14 Thread Philip Guenther
On Wed, Jan 14, 2015 at 3:10 PM, Stefan Berger berger...@wolfman.devio.us 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

Re: What exactly is sigtramp?

2015-01-14 Thread Theo de Raadt
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