[Letux-kernel] LX20 prototype is booting

[Paul Boddie]

On 2025-05-05 22:27, H. Nikolaus Schaller wrote:
> For the exec() problem I could now trace it down to arch_check_elf() in 
> arch/mips/kernel/elf.c
> And specifically:
> 
> 	https://elixir.bootlin.com/linux/v6.1.28/source/arch/mips/kernel/elf.c#L166

That is some verbose code, but highly readable, I suppose.

> But I have no idea why. And why only for x2000 and not x1600.
> 
> Values are:
> 
> [    0.017085] arch_check_elf elf32=1
> [    0.017085] arch_check_elf flags=10001007
> 
> which means that EF_MIPS_NAN2008 (=0x00000400) is not set in the flags.
> And mips_use_nan_legacy is not set at all.
> 
> So either the header is not read properly (alignment issue?) or the 
> mips_use_nan_legacy
> should be set... Which may be correct that it is not set. Then we have 
> a problem.

Now, I did read something recently, maybe related to GCC or perhaps 
Debian, about older XBurst implementations not supporting the 
appropriate MIPS floating-point semantics. This may have complicated the 
situation for MIPS32 in Debian, leading to its relegation to only 
getting support from a third party in future releases.

Paul