Installing a 64bit kernel and 32bit userland.

pix · 2009-03-03 09:21:43

Starting from Leonidas, Fedora will start installing a x64 kernel on compatible hardware, even when installing a 32-bit OS.
This should allow the kernel to better handle memory as the kernel no longer has to worry about low memory, high memory, etc...

Link http://fedoraproject.org/wiki/Features/ … ureSupport

It should be possible to do this under Arch, No ?

JGC · 2009-03-03 09:53:20

I'm already doing this on debian. In theory, you should be able to install an amd64 kernel using pacman, as pacman doesn't handle architecture differences when updating with the -U flag as far as I know.
Be sure you install the amd64 versions of all modules also.

bangkok_manouel · 2009-03-03 10:35:21

sounds interesting. is there any way to build an amd64 kernel inside this kind of hybrid systems?

/edit: is the -m64 flag passed to gcc enough?

Last edited by bangkok_manouel (2009-03-03 10:39:38)

AndyRTR · 2009-03-03 10:38:30

you would need a 64bit toolchain. so it's better to build that outside in a true 64bit Arch installation.

pix · 2009-03-03 10:41:35

It should be possible to make a x64 repo just for the kernel related stuff, copy the related pakages, and enable it by default (or not) when installing on x64 hardware

bangkok_manouel · 2009-03-03 10:42:45

Thanks for your reply Andy, I found out this while STFWing. Would that work?

man gcc wrote:

-m64
Generate code for a 32-bit or 64-bit environment. The 32-bit environment sets int, long and
pointer to 32 bits and generates code that runs on any i386 system. The 64-bit environment sets
int to 32 bits and long and pointer to 64 bits and generates code for AMD's x86-64 architecture.
For darwin only the -m64 option turns off the -fno-pic and -mdynamic-no-pic options.

Last edited by bangkok_manouel (2009-03-03 10:44:03)

pix · 2009-03-03 10:55:28

On 32bit archlinux:

pix@bozo> cat toto.c
int main(int argc, char ** argv){
  printf("Bouh\n");
}
pix@bozo> gcc -m64 toto.c -o toto
toto.c:1: sorry, unimplemented: 64-bit mode not compiled in
toto.c: In function 'main':
toto.c:2: warning: incompatible implicit declaration of built-in function 'printf'

It should be possible to recompile gcc and adding the 64bit mode support (Read: I don't know) But it isn't enabled.

Last edited by pix (2009-03-03 10:56:42)

bangkok_manouel · 2009-03-03 11:02:35

Thanks pix. I've found this on the subject:
http://linux.derkeiler.com/Mailing-List … 02950.html
Anyway, I have a 64bit arch machine that i can use so that should do it.

bangkok_manouel · 2009-03-03 15:09:28

i just installed a 64bit kernel and after ultra intensive testing (3 minutes of web browsing), everything seems to work as expected.

bangkok_manouel · 2009-03-03 16:53:36

now come the issues. i have some problems building packages while running this kernel.

/etc/makepkg.conf

#########################################################################
# ARCHITECTURE, COMPILE FLAGS
#########################################################################
#
CARCH="i686"
CHOST="i686-pc-linux-gnu"

#-- Exclusive: will only run on -march=i686 
# -march (or -mcpu) builds exclusively for an architecture
# -mtune optimizes for an architecture, but builds for whole processor family
CFLAGS="-march=i686 -mtune=native -Os -pipe -fomit-frame-pointer"
CXXFLAGS="-march=i686 -mtune=native -Os -pipe -fomit-frame-pointer"
#-- Make Flags: change this for DistCC/SMP systems
MAKEFLAGS="-j3"

Firefox fails with:

/home/eb/pkg/firefox/src/xpcom/reflect/xptcall/src/md/unix/xptcinvoke_x86_64_linux.cpp:181: error: invalid register name for 'a4'
/home/eb/pkg/firefox/src/xpcom/reflect/xptcall/src/md/unix/xptcinvoke_x86_64_linux.cpp:182: error: invalid register name for 'a5'
make[9]: *** [xptcinvoke_x86_64_linux.o] Error 1
make[9]: *** Waiting for unfinished jobs....
{standard input}: Assembler messages:
{standard input}:7: Error: bad register name `%rbp'
{standard input}:8: Error: bad register name `%rsp'
{standard input}:9: Error: bad register name `%rsp'
{standard input}:10: Error: bad register name `%rdi'
{standard input}:11: Error: bad register name `%rsi'
{standard input}:12: Error: bad register name `%rdx'
{standard input}:13: Error: bad register name `%rcx'
{standard input}:14: Error: bad register name `%r8'
{standard input}:15: Error: bad register name `%r9'
{standard input}:16: Error: bad register name `%rbp)'
{standard input}:17: Error: bad register name `%rbp)'
{standard input}:18: Error: bad register name `%rbp)'
{standard input}:19: Error: bad register name `%rbp)'
{standard input}:20: Error: bad register name `%rbp)'
{standard input}:21: Error: bad register name `%rbp)'
{standard input}:22: Error: bad register name `%rbp)'
{standard input}:23: Error: bad register name `%rbp)'
{standard input}:24: Error: bad register name `%rbp)'
{standard input}:25: Error: bad register name `%rbp)'
{standard input}:27: Error: bad register name `%rbp)'
make[9]: *** [xptcstubs_x86_64_linux.o] Error 1

qt fails with:

main.cpp:1: sorry, unimplemented: 64-bit mode not compiled in
make: *** [property.o] Error 1
make: *** Waiting for unfinished jobs....
make: *** [main.o] Error 1
make: *** [project.o] Error 1

Any idea why the building process seems not to care about the arch set in makepkg.conf and if it could be possible to fix that?

TIA

JGC · 2009-03-03 23:45:31

There's a tool called "linux32" for that. It manages to change the architecture reported by uname. I use it to build i686 packages inside my i686 chroot on my amd64 system.

dolby · 2009-03-04 06:55:26

this might also interest you

bangkok_manouel · 2009-03-04 12:58:37

JGC wrote:

There's a tool called "linux32" for that. It manages to change the architecture reported by uname. I use it to build i686 packages inside my i686 chroot on my amd64 system.

Thanks Jan, it works perfectly with linux32.

dolby wrote:

this might also interest you

Interesting read, thanks. In fact, using linux32, the only problem one would face using this kind of hybrid system is the ability to build his custom kernel.

Kilz · 2009-03-04 14:44:16

What is the purpose of this in Linux, other than to continue to slow the adoption of 64bit on hardware that supports it?

b9anders · 2009-03-05 19:48:15

I installed a 64-bit kernel on my i686 when I wanted to do a remote install of arch64 and it worked without a hitch.

Arch Linux

#1 2009-03-03 09:21:43

Installing a 64bit kernel and 32bit userland.

#2 2009-03-03 09:53:20

Re: Installing a 64bit kernel and 32bit userland.

#3 2009-03-03 10:35:21

Re: Installing a 64bit kernel and 32bit userland.

#4 2009-03-03 10:38:30

Re: Installing a 64bit kernel and 32bit userland.

#5 2009-03-03 10:41:35

Re: Installing a 64bit kernel and 32bit userland.

#6 2009-03-03 10:42:45

Re: Installing a 64bit kernel and 32bit userland.

#7 2009-03-03 10:55:28

Re: Installing a 64bit kernel and 32bit userland.

#8 2009-03-03 11:02:35

Re: Installing a 64bit kernel and 32bit userland.

#9 2009-03-03 15:09:28

Re: Installing a 64bit kernel and 32bit userland.

#10 2009-03-03 16:53:36

Re: Installing a 64bit kernel and 32bit userland.

#11 2009-03-03 23:45:31

Re: Installing a 64bit kernel and 32bit userland.

#12 2009-03-04 06:55:26

Re: Installing a 64bit kernel and 32bit userland.

#13 2009-03-04 12:58:37

Re: Installing a 64bit kernel and 32bit userland.

#14 2009-03-04 14:44:16

Re: Installing a 64bit kernel and 32bit userland.

#15 2009-03-05 19:48:15

Re: Installing a 64bit kernel and 32bit userland.

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