Re: does module area require alignment? (Re: [PATCH] i386-qemu port)

[Pavel Roskin]

On Tue, 2009-06-23 at 00:50 +0200, Vladimir 'phcoder' Serbinenko wrote:

>         I made 3 images with the gap of 0x4000, 0x8000 and 0xc000.
>          Then I added
>         an uninitialized array to the kernel, 0x4000 bytes long, and
>         made
>         another 3 images with the same gap sizes.  The images with the
>         0x4000
>         gap don't boot and the images with the gap sized 0x8000 and
>         0xc000 boot
>         regardless of the array.
> Stupid question but have you ensured/checked that this array isn't
> optimized out?

Yes, I checked that.

It turns out that small variables to to the .sbss section and reduce the
minimal gap side (0x8c50 and 0x8c54 are OK).  But larger arrays go to
the .bss section and don't change the gap (0x8c50 is bad, 0x8c54 is OK).

Maybe OpenFirmware is confused by the .sbss section.  I'll try a linker
script to merge .sbss into the .bss section.

-- 
Regards,
Pavel Roskin