Re: [PATCH] linux-2.5.43_vsyscall_A0

Ton Hospel
2002-10-19T22:27:53Z

In article <200210190352.WAA05769@ccure.karaya.com>,
Jeff Dike <jdike@karaya.com> writes:
>
> This needs to be virtualizable somehow, which means that apps run inside
> UML, without being changed, get the UML vsyscalls. There are a couple of
> possiblities that I can think of:
> a get_vsyscall system call which is executed by libc on startup -
> UML would return a different calue from the host
> some mechanism for UML to map its own vsyscall area in place of
> the host's - it wouldn't necessarily need to be able to unmap it when it's
> running its own kernel code because it can probably arrange not to use the
> host's vsyscalls.
>
> Jeff
>
In case you want UML to also be able to work as a jail, it should
actually be impossible to get to the "real" systemcalls. In that case
just asking libc is not acceptable if the other area remains available