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Re: ppc64 vDSO in mainline
- From: Benjamin Herrenschmidt <benh at kernel dot crashing dot org>
- To: Steve Munroe <sjmunroe at us dot ibm dot com>
- Cc: Ulrich Drepper <drepper at redhat dot com>, Alan Modra <amodra at bigpond dot net dot au>, libc-alpha at sources dot redhat dot com, Roland McGrath <roland at redhat dot com>
- Date: Sat, 26 Mar 2005 10:06:08 +1100
- Subject: Re: ppc64 vDSO in mainline
- References: <OFE314DC0A.50C1339C-ON86256FCE.008104F8-86256FCE.008268A5@us.ibm.com>
> Is this a hard requirement for all arches or just for i386?
>
> I can see how randomized VDSO for platforms using
> NEED_DL_SYSINFO/DL_SYSINFO_IMPLEMENTATION might prevent a virus attacker
> from using syscalls. But powerpc is a NEED_DL_SYSINFO_DSO only
> implemention and so can't prevent anyone from using syscalls inline. And I
> don't see how calling gettimeofday is a security threat?
Currently, we don't use the vDSO for syscalls, but that might change in
the future. There are things going on at the architecture folks level
that _might_ cause us to want to use a different syscall entry mecanism
for some CPUs in the future.