Want to run L4Re on Raspberry PI.

[Paul Boddie]

On Wednesday 29. May 2019 15.20.01 Matthias Lange wrote:
> 
> The issue we have with "standard" cross toolchains is the libgcc they are
> shipping. It is compiled for ARMv7 and contains instructions that are
> unknown / illegal on ARMv6k. The mean thing is, that our build system tells
> GCC via "-march=armv6zk" what code to generate but then links the wrong
> libgcc.

Some of these compiler configuration issues are awkward. My problem was that 
although there are switches for hard- and soft-float, appropriate libgcc 
variants need to be available, and the Debian toolchains do not provide them 
all. I actually don't remember if there is a need for completely separate 
compilers, but I would hope not (and yet not be surprised if it were the 
case).

Of course, it is one thing to be able to avoid certain instructions in one's 
own code, quite another to have to deal with library code liberally using 
"illegal" instructions. I got quite far with bare metal code, even targeting 
microcontrollers like the PIC32 with the MIPS compilers, for instance.

So, the Buildroot compiler it had to be.

Paul

P.S. I have a selfish interest in following this as I could imagine also 
trying out L4Re on the Raspberry Pi at some point. I guess that the 
framebuffer isn't currently supported though.