[Feature request] qemu does not support for Octeon MIPS64 on X86

[Lu Haocong]

Description of problem:

I use mips64-octeon-linux-gnu-gcc cross toolchain on X86,and generate binary file.

> mips64-octeon-linux-gnu-gcc hello.c -static
> file a.out
> a.out: ELF 32-bit MSB executable, MIPS, N32 MIPS64 rel2 version 1 (SYSV), statically linked, for GNU/Linux 2.4.0, not stripped

I execute it with mips64-linux-user mode in qemu, it is invalid.

> ./qemu-5.0.0/mips64-linux-user/qemu-mips64 a.out
> a.out: Invalid ELF image for this architecture

when I choose mips-linux-user mode, it regards as illegal instruction.

> ./qemu-5.0.0/mips-linux-user/qemu-mips a.out
> qemu: uncaught target signal 4 (Illegal instruction) - core dumped
> Illegal instruction (core dumped)

I would like to know, is this due to my problem or does qemu not support Octeon MIPS64 on X86?

if qemu has supported Octeon MIPS64 on X86, how can I emulate it.

[Aleksandar Markovic (aleksandar-markovic)]

Probably not, but there may be a workaround. The closest cpu to Octeon that is supported in QEMU is "MIPS64R2-generic".

Please try using switch -cpu MIPS64R2-generic in your QEMU command line.

Also, I think you should use qemu-mipsn32 rather than qemu-mips or qemu-mips64.

I don't have much hope that all this will work, but it is worth trying.

[Aleksandar Markovic (aleksandar-markovic)]

Hi, Lu.

Where can I download Octeon toolchain you used?

I want to try it by myself.

Aleksandar

[Thomas Huth (th-huth)]

Was the MIPS64R2-generic good enough for you?

[Philippe Mathieu-Daudé (philmd)]

If your file is "ELF 32-bit MSB executable, MIPS, N32 MIPS64 rel2 version 1",
then you have to use the mipsn32-linux-user variant of QEMU (binary 'qemu-mipsn32').