[Xen-users] can't find a register in class `BREG' while reloading `asm'

[Kevin <lists@xxxxxxxxxxxxx>]

Hi List-

I'm brand new to xen but an old hand with Linux.

With a fresh, clean, Gentoo installation on this box, I'm attempting to
install xen using the gentoo-standard:

emerge xen

but the process is failing with an error that's very similar to one
reported by another user (A Streetcar Named: see
http://lists.xensource.com/archives/html/xen-devel/2004-11/msg00593.html)
in the xen-devel list back in 2004 which is why I'm posting here and not
to the gentoo lists.  I think they would answer by saying,
"...upstream...," so I'm starting upstream.

The error is:

<snip>
gcc -O2 -fomit-frame-pointer -DNDEBUG -m32 -march=i686 -Wall
-Wstrict-prototypes -Wdeclaration-after-statement -nostdinc -fno-builtin
-fno-common -fno-strict-aliasing -iwithprefix include -Werror
-Wno-pointer-arith -pipe
-I/var/tmp/portage/xen-3.0.2/work/xen-3.0.2/xen/include
-I/var/tmp/portage/xen-3.0.2/work/xen-3.0.2/xen/include/asm-x86/mach-generic
-I/var/tmp/portage/xen-3.0.2/work/xen-3.0.2/xen/include/asm-x86/mach-default
-msoft-float -g -D__XEN__ -c multicall.c -o multicall.o
memory.c: In function `guest_remove_page':
/var/tmp/portage/xen-3.0.2/work/xen-3.0.2/xen/include/asm/mm.h:206:
error: can't find a register in class `BREG' while reloading `asm'
make[2]: *** [memory.o] Error 1
make[2]: *** Waiting for unfinished jobs....
multicall.c: In function `do_multicall':
multicall.c:43: error: can't find a register in class `BREG' while
reloading `asm'
make[2]: *** [multicall.o] Error 1
grant_table.c: In function `do_grant_table_op':
/var/tmp/portage/xen-3.0.2/work/xen-3.0.2/xen/include/asm/mm.h:206:
error: can't find a register in class `BREG' while reloading `asm'
/var/tmp/portage/xen-3.0.2/work/xen-3.0.2/xen/include/asm/mm.h:206:
error: can't find a register in class `BREG' while reloading `asm'
/var/tmp/portage/xen-3.0.2/work/xen-3.0.2/xen/include/asm/mm.h:206:
error: can't find a register in class `BREG' while reloading `asm'
make[2]: *** [grant_table.o] Error 1
make[2]: Leaving directory
`/var/tmp/portage/xen-3.0.2/work/xen-3.0.2/xen/common'
make[1]: ***
[/var/tmp/portage/xen-3.0.2/work/xen-3.0.2/xen/common/built_in.o] Error 2
make[1]: Leaving directory
`/var/tmp/portage/xen-3.0.2/work/xen-3.0.2/xen/arch/x86'
make: *** [/var/tmp/portage/xen-3.0.2/work/xen-3.0.2/xen/xen] Error 2
make: Leaving directory `/var/tmp/portage/xen-3.0.2/work/xen-3.0.2/xen'

The gentoo USE flags I've chosen are as follows:

[ebuild  N    ] app-emulation/xen-3.0.2  -custom-cflags -debug -pae 0 kB

I am using a somewhat non-standard gentoo profile:

lrwxrwxrwx 1 root root 51 May  4 15:24 /etc/make.profile ->
../usr/portage/profiles/selinux/2005.1/x86/hardened

And I do have SELinux successfully installed although I'm running in
permissive mode so I don't think SELinux has anything to do with this.
It may be the case, though, that the hardened part of the profile I've
chosen is a part of the problem.

The other thread that cropped up with similar error messages was also a
Gentoo hardened box and there was no resolution posted although the
fellow's initial problem (failure to compile) was apparently resolved by
the elimination of some (all?) of the hardened flags during compilation:

"-nopie fixed the  originally reported error, but I subsequently got
other errors that said something like "undefined reference to
`__guard'" and "undefined reference to `__stack_smash_handler'".
Adding -fno-stack-protector seems to have solved these as well, and
I'm now compiling the kernels for the crusoe."

My gcc version is:

gcc (GCC) 3.4.6 (Gentoo Hardened 3.4.6-r1, ssp-3.4.5-1.0, pie-8.7.9)

I started off with 3.4.5 and similar or identical parameters for ssp and
pie.  The results in that case were the same so I've tried two different
 gcc versions (though both are hardened with pie/ssp) to no avail.

I'm not using Pax or Grsecurity or RSBAC and like I said, SELinux is
running in permissive mode right now.

In the old thread, Keir Fraser wrote:

"I've checked in a patch to the unstable tree that will allow to build
with PIE/SSP-enabled GCC."

So my hope is to be able to get xen running with these hardened flags,
but I'm wondering if something else needs to change with xen first.

I haven't yet tried compiling under the guidance that Keir gave back in
2004 (and that worked for Streetcar), but I can if it would help.  I
suspect that like the other guy, this would get xen to compile
successfully, but I'd really like to keep the hardened nature intact so
I'm asking about that first.

Thanks in advance for any ideas.

-Kevin

PS. If I should post to xen-devel, someone please tell me and I'll do so.

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