Re: [gentoo-user] duplicate gentoo system - errors

[William Kenworthy]

On 23/11/20 10:10 pm, Walter Dnes wrote:
> On Sun, Nov 22, 2020 at 04:39:44PM -0700, thelma@×××××××××××.com wrote
>> Duplicating was easy, but when I try to recompile a kernel I get an error:
>>
>> make menuconfig
>> HOSTCC script/kconfig/mconf.o
>> <build-in> : internal compiler error: Illegal instruction
>>
>> Even if I try to run: emerge --info  I get:
>> Illegal instruction
>   Ouch!  Are the CPUs exactly identical?  If not, then you may get the
> "Illegal instruction" error.  This is a "feature" of Gentoo, which is
> often user-optimized for a specific CPU.  What's the CPU on the source
> machine and what's the CPU on the target machine?  If in doubt,
> execute...
>
> gcc -c -Q -march=native --help=target | grep march=
>
> ...on each machine.  There are 3 sub-families of "Intel" machines.
>
> 1) bog-standard Intel code, e.g. core2, also runs on AMD and Intel Atom
>    CPUs at least as new or newer.
>
> 2) Intel Atom code runs only on same or newer Intel Atom, because it has
>    the MOVBE instruction set the others lack.
>
> 3) AMD code runs only on same or newer AMD, because it has the 3DNow!
>    instruction set the others lack.
>
>   If you have such a mismatch, your only option may be to rebuild from
> scratch.
>
quick package the toolchain packages from the wanted cpu system, untar
them in the root of the new system so they overwrite the existing
package files, do an emerge -e @system, then follow with another for
world.  Can also use the install CD packages - I have used some quite
different versions when recovering a broken system so it <can> work :).

Have done it a few times, its a bit messier than than just
gcc/glibc/libtool/binutils for the toolchain but does work.  The two
emerge -e shouldn't be strictly necessary, but it seems to get a better
result than just doing world.


BillK