Re: [gentoo-user] Anybody got a Gentoo system working under uclibc?

On Wed, Apr 27, 2016 at 12:25:41PM -0500, Corbin wrote
>
> On 04/27/2016 09:12 AM, waltdnes@××××××××.org wrote:
> >    I'm testing uclibc in a 32-bit QEMU Gentoo VM.  I want to eventually
> > install on my ancient 32-bit-only netbook.  I'm running into problems.
> > See https://forums.gentoo.org/viewtopic-p-7912494.html
> >
> >    To summarize...
> >    * static IP works for eth0, but dhcpcd fails, which is bad news for a
> >      laptop or netbook
> >    * when building x-rg-server, the builds for xf86-input-keyboard and
> >      xf86-video-intel fail to compile
> >    * www-client/w3m fails to build, so I can't even get decent textmode
> >      web browsing
> >
>
> You already found my test load :)
> Glad it helped someone.
>
> Did you have/add "evdev" in "make.conf" for INPUT_DEVICES?
> "evdev" is built-into-the-kernel or a kernel module. The newer input
> function, augmenting/replacing the AT keyboard and /dev/psaux.
> ( Seems "evdev" is almost replacing the functions of "xf86-input"
> libraries for Xorg.)

  No.  Do I have to set something in the kernel?  Will the keyboard work
with evdev and without xf86-input-keyboard?  My netbook uses framebuffer
video driver, so I might try using that in the uclibc VM.

> What CPU flags did you set/unset for the build?
>
> My reason for asking ... a lot of software has an unmarked dependency on
> "sse/sse2". If the info on the Atom CPU I found was correct ... it
> doesn't have sse/sse2 instruction sets.

  My Atom netbook has them, according to /proc/cpuinfo

flags           : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge
mca cmov pat clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe nx
constant_tsc arch_perfmon pebs bts aperfmperf pni dtes64 monitor ds_cpl
vmx est tm2 ssse3 xtpr pdcm movbe lahf_lm dtherm tpr_shadow vnmi
flexpriority

  Note also the "movbe" flag.  *I CANNOT TEST RUN MY NETBOOK-OPTIMIZED
CODE I BUILD IN THE QEMU VM*.  QEMU claims to emulate "Atom" CPUs.
There are over 100 different atoms in the periodic table known to
physicists, and Intel is just as bad, with all their "Atom" variants.
QEMU's "Atom" emulation does not support the "movbe" flag.  So I simply
run with the host CPU in a 32-bit VM, and set "-march=native".  When
building for the netbook, I build with "-march=bonnell".  Important
distinction...

different "-march" values != crossdev

  As long as the "CHOST" variable is identical, you can build for
different "-march" variants, even those that won't run in the build
environment.

> Useful Info : https://wiki.gentoo.org/wiki/Safe_CFLAGS

See also http://gentoo-en.vfose.ru/wiki/Safe_Cflags#-march.3Dnative

gcc -march=native -E -v - </dev/null 2>&1 | grep cc1

  Ignore all the fancy flags.  Both of those pages come up with output
that shows "-march=bonnell" on my Atom
https://en.wikipedia.org/wiki/Bonnell_%28microarchitecture%29

  I have a standard glibc 32-bit VM which I use for Gentoo distcc for
the Atom, as well as manually building Pale Moon web browser.  I use the
following settings for both...

CFLAGS="-O2 -march=bonnell -mfpmath=sse -pipe -fomit-frame-pointer \
-fno-unwind-tables -fno-asynchronous-unwind-tables"

CCFLAGS="${CFLAGS}"

  "-march=bonnell" implies all the other flags, so no need to enter them
into the CFLAGS variable.

  Thanks for that initial post.  I had almost given up on even a minimal
install, before I found it.

-- 
Walter Dnes <waltdnes@××××××××.org>
I don't run "desktop environments"; I run useful applications