Re: Looking for advise on debugging a non-boot kernel on qemu-system-sh4

[BALATON Zoltan]

On Thu, 21 Oct 2021, John Paul Adrian Glaubitz wrote:
> On 10/21/21 15:49, BALATON Zoltan wrote:
> > So somthing seems to overwrite it. Maybe you can try building an uncompressed
> > kernel or one using a different compression and see if that does the same, at
> > least that way we can see if it's in the decompressing or later. I think it's
> > past linux/arch/sh/boot/compressed/head32.S and maybe somewhere in 
> > decompress_kernel
> > but not sure which decompression it uses. Kernel config is also missing to check
> > but I probably give up at this point and let you experiment some more.
>
> I think I've seen problems with compressed kernel images and QEMU before. I 
> will switch
> to an uncompressed kernel and try again.

How did you compile the kernel that does not boot? What config have you 
used? I've tried to reproduce it by compiling a kernel with 
rts7751r2d1_defconfig and different compression methods but it did start 
and never got the problem seen with your kernel. Maybe it's the gcc 
version? My cross compiler is 8.4.0 and you seem to use 10.x. Maybe newer 
gcc uses something that's not emulated correctly? It would be interesting 
to identify what's causing the problem.

Regards,
BALATON Zoltan