Re: [gentoo-user] Upgrading old kernel

[james]

On 4/15/20 10:59 PM, Thomas Mueller wrote:
> On 4/15/20 1:40 PM, Andreas Stiasny wrote:
>> On 15.04.20 17:50, Rich Freeman wrote:
>
>>> Jumping from
>>> 3.18 you're somewhat more likely to run into issues - your biggest
>>> headache though will be dealing with the 30,000 prompts you get from
>>> make oldconfig and making sure you set all the new options correctly.
>
>> That's why I use make olddefconfig in such a case. This takes all the
>> old config values and uses the default for the new ones. If you know
>> that you need one or more of the new config options you can fine tune
>> them afterwards with make menuconfig.
>
>
>> Andreas
>
> james responded:
>
>> Ah. never used olddefconfig, I'll give it a spin.
>
> That raises the question, what if you have no kernel config, as may be the case if you are going to Gentoo for the first time, or are cross-compiling from FreeBSD or NetBSD?
>
> I have tried with OpenADK (www.openadk.org), which got as far as successfully building cross-gcc some of the time, but never succeeded at building the kernel.
>
> Is defconfig the best starting point?  One would want to maximize the probability of success building the kernel while retaining a functional system that would support vital hardware including ethernet, wi-fi, hard drives and USB, and I would need to be able to read a NetBSD or FreeBSD file system (UFS/FFSv1 or 2).  I use GPT, so there are no traditional now-deprecated BSD disklabels that Linux would not recognize.
>
> If I just start with menuconfig, I could miss some vital parts.
>
> OpenADK started with a minimal kernel config, maybe it was too minimal?
>
> I have successfully compiled kernels and userlands on FreeBSD and NetBSD (no menuconfig, defconfig, etc; kernel configs start with a GENERIC config).  NetBSD kernel config is much longer than FreeBSD kernel config but is dwarfed by Linux kernel config.
>
> Tom

OK, time to spill 'the beans'.

OpenADK does not look like a kernel building tool. Booting a minimal 
state-machine for an embedded device, starts at the bottom of the code 
blocks.


Building a linux kernel, that runs on the bottom of processors, guaged 
by resources and capabilities has always been a 'pita' that is nothing 
but duress. As you down the tree of what micro-processors can do, and 
the limited (kernel/system) resources, limited instruction sets, etc, 
etc  that need is not common and you are best off following a well worn 
path. Folks that do not deeply understand the lack or limited (uP) 
resources and the subsequent limitied options available, need to get 
into a good, university program or go write assemble code on uPs for a 
few years. In essence, that sort of approach is a giant waste of time. 
I.E. follow a well worn path and learn to code in C and assembler. 
Executive, minimal OS and such, written in forth or other such languages 
are shear folly.  C and Assembler, for find something else to do with 
your time, wisely.


However, that said, integrating certain processor family trees into what 
other, more sophisticated 64 bit arm projects are doing, particularly 
with low level codes, is a wise idea. Pick your battles wisely. Caveat 
Emptor!


Back to my thread::
An older, existing system is very rich in unique work and codes, at 
least for me, so I keep old image-systems, around for decades. A Gentoo 
packrat, as I can quote from very smart people back to 2004, when 
necessary. Their words were and are true, but, let's focus on 
virgin/noob (kernel-centric) systems issues.


Fast Forward.
I use the install disk from CloverOS which does a wonderful job of auto* 
for recent kernels and many packages. However it is not portage_raw or 
the myriad of other places to download and install or hack ebuilds; not 
necessarily of the Gentoo-approved feedstock. ymmv.


CloverOS will give you a clean, new kernel, but lacks a window system (I 
do not use anything big, regardless of system resources) that is 
functional but not robust, imho.


But 10 (15 max) minutes for a gentoo install is just freaking awesome, 
btrfs and a new kernel 5.* kernel.
I have not tried to just copy over a kernel and associated file, but 
that is on the list as I have (3) identical AMD systems, 64bit, with AMD 
video cards and 32 G of DDR3 memory. But I shall just try to copy over a 
kernel derived from the CloverOS gentoo to an indentical hardware system 
running a version 3.18 james-derived-and-build linux kernel, just to see 
what happens.


So a hybrid technique to rapidly test pre-built kernels, in an automated 
fashion, then going back and duplicating the same kernel-builds-tests 
from a kernel-gentoo-source-package, would be and attractive experiment 
to me.


One off (which is what we do as a gentoo collective of hacks) kernels 
with the build-test-repeat cycle seems like an arcane semantic for a 
collective of experts (or fledgling gentoo-soon-to-be-experts)in this 
day and age (strictly of my opine).


Where I'm going, managing a collective of hundreds or thousands of 
gentoo derivative systems (from small arm embedded) to workstations and 
servers, is way, way past due an automated and auto-managed tool-system. 
So, I'm not the best person to weigh in here. This problem has been 
solved, hundreds of times, by really smart people, but most all have 
gone commercial::


Gentoo spawned CoreOS (multi-booting-many-kernel choices-automated) 
which was purchased by Redhat, which experienced a hostile takeover by 
IBM. IBM is now filing bankruptcy, to get billions of tax payer dollars 
from the US taxpayers, whilst running full steam ahead with a 
gentoo-derivative OS. I'm not sure why the good work at CoreOS, did not 
make it back into the Gentoo mainstream.
(Rich or some other smart Gentooer could/should enlighten us?).


So is it not time for a few, very smart Gentoo devs to build us a simple 
tool? Not one that does everything, but that does enough to make/track 
new kernel builds streamlined and easy? Every system should have a dozen 
or more viable kernels for a wide variety of reasons (imho.).


Then the greater gentoo community could go off, each in their own, 
tractor inspired, direction with 'tuned, optimized and secure' unique 
kernels to plow the fields they plant?  (a plea for help?)? leadership?


Was Andrew Gaffney booted out of Gentoo, for similar ideas as James? 
Surely he has superior skills.....

https://blogs.gentoo.org/agaffney/2006/01/18/installer_philosophy/



I could tagged hundreds, but what's the point.....


James