Andi Kleen wrote:
> It needs COMPAT_VDSO
>
> [which is basically COMPAT_NO_OLD_GLIBC and imho always
> was a big mistake to have a config anyways -- one shouldn't gamble
> with binary compatibility so lightly]
>
It's unfortunate; there's a fundamental address space clash, and there's
no nice resolution.
Will your system boot with vdso=0 on the kernel command line?
Presumably it will boot paravirt-native without it (since native makes
no claims on the address space), so its something you could put in your
Xen config file, no?
> Hmm, i had assumed it used the same mechanism as the CPU optimized
> libcs -- and that comes from the aux vector AT_PLATFORM.
>
There's some magic that involves a .note segment in the vdso itself, and
a ld.so.conf entry which maps the string in there ("nosegneg") to a
pseudo-hardware capability, and ld.so uses the result of that to look
for more places for libraries. I don't really understand how all the
pieces fit together.
> Why does it not boot? At least in the past nosegneg was only a optimization
> to avoid some unnecessary traps to the hypervisor, but it should handle it.
> Has that changed?
>
No, but my (very stripped down) test system has no other libraries.
J
