On Thu, 23 Mar 2006, Blaisorblade wrote:
On Thursday 23 March 2006 00:55, David Lang wrote:
is there a way to build a i386 uml kernal on amd64?
I have a 64 bit debian build on my main box, but I need to run a uml
instance useing a 32 bit debian system image. I've attempted to use the
same uml kernel that I have been useing for my earlier attempts, but it
dies with an oops complaining about a missing init.
I'm currently trying to see if recompiling my host kernel to support ia32
binaries makes a difference, but I suspect that it won't (it may allow me
to compile a uml kernel on a 32 bit machine and use it for this, that will
be my next test)
That's _required_ but not enough; to run a 32-bit UML binary you _need_ that
support on the host.
yep, I didn't realize it was missing before this test.
shouldn't there be a way to turn on this ability on a UML kernel? (so that
it can run a mixed 32/64 userspace)
Btw, you can also download pre-built UML binaries from my homepage (see
signature), and this is useful even to determine what's going on (e.g. say
that binary work, your one doesn't, let's compare configurations! Or a couple
of months ago the answer was "let's blame this GCC", but this story is now
old).
sorry, I've been building cusom kernels too long. it never occured to me
to download a kernel from anywhere else (even distro kernels are only on
my machines long enough to install, download the latest kernel.org source,
and recompile. and that's assuming I don't have a kernel sitting ready
from another box :-)
It's ages I don't build a 32-bit binary on a 32-bit system. Simply replace
"ARCH=um" with "ARCH=um SUBARCH=i386" in all the configuration commands.
However, this presumes that libs to link/run 32-bit programs are installed.
thanks, I hadn't known about SUBARCH before this.
unfortunantly it doesn't seem to work for me
make ARCH=um SUBARCH=i386 mrproper
copy ../config.uml-64 .config
make ARCH=um SUBARCH=i386 oldconfig
make ARCH=um SUBARCH=i386
results in
secdev:/usr/src/linux-2.6.16# make ARCH=um SUBARCH=i386
SYMLINK arch/um/include/kern_constants.h
SYMLINK arch/um/include/sysdep
gcc -Wall -Wundef -Wstrict-prototypes -Wno-trigraphs -fno-strict-aliasing -fno-common -ffreestanding -Os -fomit-frame-pointer -D__arch_um__ -DSUBARCH=\"i386\" -Dvmap=kernel_vmap -Din6addr_loopback=kernel_in6addr_loopback -Iarch/um/include -I/usr/src/linux-2.6.16/arch/um/include/skas -D_FILE_OFFSET_BITS=64 -m32 -march=athlon -mpreferred-stack-boundary=2 -D_GNU_SOURCE -D_LARGEFILE64_SOURCE -S -o arch/um/user-offsets.s
arch/um/sys-i386/user-offsets.c
arch/um/sys-i386/user-offsets.c: In function `foo':
arch/um/sys-i386/user-offsets.c:51: error: invalid application of `sizeof' to
an incomplete type
arch/um/sys-i386/user-offsets.c:53: error: `EIP' undeclared (first use in this
function)
arch/um/sys-i386/user-offsets.c:53: error: (Each undeclared identifier is
reported only once
arch/um/sys-i386/user-offsets.c:53: error: for each function it appears in.)
arch/um/sys-i386/user-offsets.c:54: error: `UESP' undeclared (first use in this
function)
arch/um/sys-i386/user-offsets.c:55: error: `EFL' undeclared (first use in this
function)
arch/um/sys-i386/user-offsets.c:56: error: `EAX' undeclared (first use in this
function)
arch/um/sys-i386/user-offsets.c:57: error: `EBX' undeclared (first use in this
function)
arch/um/sys-i386/user-offsets.c:58: error: `ECX' undeclared (first use in this
function)
arch/um/sys-i386/user-offsets.c:59: error: `EDX' undeclared (first use in this
function)
arch/um/sys-i386/user-offsets.c:60: error: `ESI' undeclared (first use in this
function)
arch/um/sys-i386/user-offsets.c:61: error: `EDI' undeclared (first use in this
function)
arch/um/sys-i386/user-offsets.c:62: error: `EBP' undeclared (first use in this
function)
arch/um/sys-i386/user-offsets.c:63: error: `CS' undeclared (first use in this
function)
arch/um/sys-i386/user-offsets.c:64: error: `SS' undeclared (first use in this
function)
arch/um/sys-i386/user-offsets.c:65: error: `DS' undeclared (first use in this
function)
arch/um/sys-i386/user-offsets.c:66: error: `FS' undeclared (first use in this
function)
arch/um/sys-i386/user-offsets.c:67: error: `ES' undeclared (first use in this
function)
arch/um/sys-i386/user-offsets.c:68: error: `GS' undeclared (first use in this
function)
make: *** [arch/um/user-offsets.s] Error 1
At least glibc, but I guess this is not the case for you since your kernel
didn't support 32-bit binaries.
====
You say:
"compiling a uml kernel on a i386 and trying to run in resulted in 'file
not found' (shared libraries not there for the 32 bit software on the 64
bit system)"
this can mostly or totally be solved by enabling "Static linking" near where
you disable TT mode (which has also other unrelated advantages).
compiling the new 64 bit kernel as I type
For the last error you get, try adding stderr=1 and see if something more is
reported. That error is likely caused by some yet-to-be-determined simple
misconfiguration (say, in the image something is missing). But I'd test first
with static linking.
I get the exact same error with a static UML kernel (compiled from the 32
bit system) as with the dynamic one, and adding stderr=1 makes no change.
when I get into the office tomorrow I'll download some 32 bit kernels from
your site and give them a try.
David Lang
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