Re: [Qemu-devel] proposal: drop linux-user unicore32 support from QEMU

[Riku Voipio]

On Thu, Sep 22, 2016 at 11:09:55PM +0800, MPRC wrote:
> Hi, I'm fixing the syscall problem for linux-user/unicore32 in qemu.
> 
> I write a "hello world" program to test linux-user/unicore32 in qemu 2.7 with 
> toolchain of uc4-1.0.5(you can download it through 
> http://mprc.pku.edu.cn/~guanxuetao/linux/uc4-1.0.5-hard.tgz). And it's just 
> OK.
> It goes well in the old version qemu that we using, also.
> 
> Can you discribe the bug more detailed? Or how do you find that the unicore32 
> don't use the real syscall numbers?
> How should test this? By Linux Test Project? It's not necessary to do all 
> test in LTP.

The problem we see is that the system call numbers in qemus
unicore32/syscall_nr.h dont match what is linux mainline kernel. From the
toolchain linked, you seem to have kernel headers and syscall numbers 
based on a custom 2.6.32 fork. If one builds unicore32 binaries based on
Linux 4.4 kernel headers, they will not work qemu. OTOH the binary built
with the toolchain you linked, would not work with linux 4.4. This
disparity is what we'd like to get fixed.

Riku