Re: [Valgrind-developers] Progress with the new address space manager

[Julian S. <js...@ac...>]

> The major outstanding problem I'm seeing on x86 is the redirection
> of _dl_sysinfo_int80 to a routine inside valgrind as valgrind now
> refuses to do a translation from code in an SkFileV segment. There
> is a similar problem with the vsyscall routines on amd64.

One possibility is to use the same solution Jeremy devised for 2.2.0,
which was to copy that code to a page in the initial client stack and
use a system of offsets to figure out where the entry points went.

That's a bit awkward because of the offsets.  Another possibility 
is to find the one page which these routines occupy and change its
ownership from V to C.  In order to ensure that the client didn't
inadvertantly acquire execute permission for any other bits of V
which happened to lie on that one page, we could put 4096 bytes
worth of ud2s immediately before and after the routines.  That 
would guarantee that the only useful stuff in the page is the
routines themselves.

What do you reckon?  Insane hack or plausible?

J