[PATCH] dl: Use "adr" assembler command to get proper load address

[Lukasz Majewski]

Hi Adhemerval,

> On 08/09/2021 12:05, Lukasz Majewski wrote:
> > 
> > The r1 gets the 0xffffee80 (negative offset) value. It is then
> > added to pc and used to calculate r2.
> > 
> > For working code (with this patch applied) - there are NO such large
> > values (like aforementioned 0xffffee80). The arithmetic is done on 
> > 
> >    1690:       00000020        .word   0x00000020
> >    1694:       0002be7e        .word   0x0002be7e
> > 
> > which seems to work.
> > 
> > This shouldn't be a problem as with U2 the arithmetic shall work.
> > However, I've noticed (with passing LD_DEBUG=all) that the
> > ld-linux-armhf.so.3 (and init) are relocated twice before execution.
> > 
> > Why do we need to relocate it?
> > 
> > Another question is why on this particular case the large (i.e.
> > negative) offset matters?  
> 
> I think it is highly unlikely the negative offset plays any role here.
> Do you have a working example to trigger this issue? 

I'm just using QEMU (runqemu -d y2038-image-devel nographic) from
meta-y2038 build.

Recent versions: 
poky: SHA1: 1e2e9a84d6dd81d7f6dd69c0d119d0149d10ade1
qemu_6.0.0
binutils_2.37
gcc_11.2

The QEMU board uses Cortex-A9 core.

> I am currently
> testing arm for different compilers (gcc 6.2, gcc 10, gcc 11) and
> with different configurations (armv5, armv6, armv7, with and without
> thumb) and I haven't see any issue so far.
> 
> It might binutils related, which version are you using?




Best regards,

Lukasz Majewski

--

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