i486 motivation thread

andreas_baumann · 2019-05-15 08:58:52

I should check if NBD is enabled in the standard kernels..

At least in newer kernels this should be the case:

https://git.archlinux32.org/archlinux32 … i486#L2214
CONFIG_BLK_DEV_NBD=m

BTW, you can also use NFS with the nfs mkinitcpio hook..

Sorry for the trouble, but everything i486-ish is more or less in development/experimental condition, so
there is a lot of room for things which can go wrong. :-)

tkteun · 2019-05-15 14:05:32

Okay, I found out my nbd server had permission issues, running as root now

Going back to the first append option from your list I managed to boot into the image

But now I find out that it's running as i686 while I specifically remember that not working in the past, but now it reports the CMOV instruction. Maybe there was a bug in older kernels which rendered it useless, but changing to the i686 squashfs also just works. (Pretty sure the meltdown/spectre bugs are inaccurate)

archiso# cat cpuinfo 
processor	: 0
vendor_id	: CentaurHauls
cpu family	: 6
model		: 9
model name	: VIA Nehemiah
stepping	: 8
cpu MHz		: 998.700
cache size	: 64 KB
physical id	: 0
siblings	: 1
core id		: 0
cpu cores	: 1
apicid		: 0
initial apicid	: 0
fdiv_bug	: no
f00f_bug	: no
coma_bug	: no
fpu		: yes
fpu_exception	: yes
cpuid level	: 1
wp		: yes
flags		: fpu vme de pse tsc msr cx8 sep mtrr pge cmov pat mmx fxsr sse cpuid rng rng_en ace ace_en
bugs		: cpu_meltdown spectre_v1 spectre_v2 spec_store_bypass l1tf
bogomips	: 1997.40
clflush size	: 32
cache_alignment	: 32
address sizes	: 32 bits physical, 32 bits virtual
power management:

archiso# uname -a
Linux archiso 4.18.16-arch1-1.0-ARCH #1 SMP PREEMPT Tue Oct 23 23:21:51 CEST 2018 i686 GNU/Linux
archiso# lscpu
Architecture:        i686
CPU op-mode(s):      32-bit
Byte Order:          Little Endian
CPU(s):              1
On-line CPU(s) list: 0
Thread(s) per core:  1
Core(s) per socket:  1
Socket(s):           1
Vendor ID:           CentaurHauls
CPU family:          6
Model:               9
Model name:          VIA Nehemiah
Stepping:            8
CPU MHz:             998.700
BogoMIPS:            1997.40
Flags:               fpu vme de pse tsc msr cx8 sep mtrr pge cmov pat mmx fxsr sse cpuid rng rng_en ace ace_en

Now I've been busy trying to get the default i686 image to do the same thing... Unfortunately the "copytoram=n" option isn't enough for the default boot.

Also using this initramfs it starts complaining about not having /dev/disk/by-label/ ARCH?? when using these options.

andreas_baumann · 2019-05-15 15:55:38

So, the kernel boots, the initial ramdisk gets loaded via TFTP.
Do you use the last i486 ISO image (http://archlinux32.andreasbaumann.cc/arch486isos/)
This is the first method (running from the virtual ISO).

There is an alternative method using an older file system I have (arch486install.img, basically
it's the i486 chroot installed and exposed as NBD block device, but it's kinda big as it was
used to bootstrap the i486 system).

[arch486install]
exportname = /data/nbd/arch486install.img
copyonwrite = true

I put it onto http://archlinux32.andreasbaumann.cc/tftp/

In any case, when you get a prompt you have to use pacstrap with --arch=i486 to
install to the hard disk.

You don't happen to have a CDROM drive you can attach temporarily?
This is by far easier than going over PXE.. :-)

deep42thought · 2019-06-15 15:56:32

small update on the alix: andreas_baumann kindly helped me to get archlinux32 (i486) running on that thing, so my soon-to-be-in-production router now also tests the i486 branch

(the card on top is the old 4GB CF-card holding the debian - in case we screwed up)

Arch Linux

#26 2019-05-15 08:58:52

Re: i486 motivation thread

#27 2019-05-15 14:05:32

Re: i486 motivation thread

#28 2019-05-15 15:55:38

Re: i486 motivation thread

#29 2019-06-15 15:56:32

Re: i486 motivation thread

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