> Am 09.09.2021 um 16:01 schrieb David Boddie <[email protected]>: > > On Thursday, 9 September 2021 14:18:50 CEST H. Nikolaus Schaller wrote: > >> But in the meantime I got another hint: maybe the same reason why the SD >> size limits exist. >> >> Pi 0, 1, 2 use an ARMv6 while the others (except Pi 4) use ARMv7. > > I assumed you already knew about that. :-)
Well, I knew but wasn't aware... When I started the GTA04 project long long ago (before RasPi 1 was even announced) with OMAP3 it was already ARMv7... The GTA02 was likely ARMv6 but I never compiled anything for it. > > I think 2 uses an ARMv7 core: > > https://en.wikipedia.org/wiki/Raspberry_Pi#Specifications Ok, may be slightly different than my assumptions. > >> This finally explained to me why there is kernel.img and kernel7.img... >> It is not strictly necessary to have two kernel builds and it turned out >> that changing the letux_defconfig from >> >> # CONFIG_ARCH_MULTI_V6 is not set >> CONFIG_ARCH_MULTI_V7=y >> CONFIG_ARCH_MULTI_V6_V7=y >> >> to >> >> CONFIG_ARCH_MULTI_V6=y >> CONFIG_ARCH_MULTI_V7=y >> CONFIG_ARCH_MULTI_V6_V7=y >> >> makes the kernel start on both :) Well, there are differences >> (single core vs. quad core, different memory size etc.) but this >> is taken care of by device tree and kernel. >> >> But it fails running the Debian rootfs binaries (at least the >> one I have tried so far). The same µSD plugged into the 3b+ boots >> and runs fine. >> >> So there must be something special in Raspbian or Debian for ARMv6. > > My understanding was that Raspbian was initially a complete rebuild of Debian > for ARMv6. > > According to the Debian Wiki: > > "Raspberry Pi OS builds a single image for all of the Raspberry families, > so you will get an armhf 32-bit, hard floating-point system, but built for > the ARMv6 ISA (with VFP2), unlike Debian's ARMv7 ISA (with VFP3) port." > > [https://wiki.debian.org/RaspberryPi] > > So it's likely that stock Debian binaries won't run on a Pi Zero. Ok, that would explain a lot... I did check what debian-architectures reports on Raspbian and it was indeed armhf. Let's see what we can do with this for LetuxOS. What I got from some experiments of Debian Stretch binaries on Raspbian is SIGSEGV and not SIGILL. Hm. Is there an ARMv7 emulator for ARMv6? Or a patch for missing instructions? Or I just build and install armel rootfs packages for https://download.goldelico.com/letux-debian-rootfs/?C=M;O=D And makesd needs a simple flag to switch its macros for Raspi. This will not optimally handle VFP of course, but should work for standard stuff. So with this a more general LetuxOS4Pi is close. BR, Nikolaus _______________________________________________ Community mailing list [email protected] http://lists.goldelico.com/mailman/listinfo.cgi/community http://www.tinkerphones.org
