Re: Kernel image size limitations silo?
On 28/12/15 14:11, crn@netunix.com wrote:
> It is not that simple.
> Basically ( the Oracle guys should know more ) the OBP only initialises
> a small block of memory so your image must fit into that space until it
> has initialised enough memory management to use more space.
> The clue is to cut the image down to the absolute minimum to get the
> install started. Its a long time ago so my memory is a tad vague, I
> seem to recall needing to use pivot root when I was working on Sparc32.
>
> Hope this helps.
According to the IEEE-1275 specification, 8M of memory is allocated at
load-base (0x4000 default) by OBP, which is also what OpenBIOS does.
Pretty much every bootloader I've looked at works by loading itself at
load-base and then calling the OBP alloc routines based upon parsing the
ELF header to reserve a chunk of memory for the kernel. These
allocations are reflected in the memory and virtual-memory node memory
properties which are subsequently parsed by the kernels to ensure that
these mappings are maintained until the kernel takes over.
ATB,
Mark.
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