Re: bootxx_ffsv1 compilation failure on amd64

[David Laight <david%l8s.co.uk@localhost>]

On Wed, Jan 22, 2014 at 02:31:26PM -0800, alakesh haloi wrote:
> Hi David
> 
> Thanks for your reply. The kernel boots if ramdisk is <= 16mb.
> The kernel itself is around 12.5MB. So it definitely boots for
> kernel+ramdisk >16MB. In fact i could go few KB beyond 16MB ramdisk.
> I could actually recompile the boot loader with my prints and see
> that the system resets after it starts executing the kernel.
> When i added some printfs inside once it went forward till initializing
> sysclts and then crashed with uvm page fault.

Another guess - I'm quite good at them.

Assume the kernel and ramdisk get loaded into memory ok.
(If the ramdisk were corrupt you'd find out later anyway.)

So it might be that the kernel only maps 32MB of memory for somthing,
and needs the kernel, ramdisk and probably some other stuff fit
within that space.

I've not really looked at the virtual memory layout that closely.

About the first thing the kernl must do is setup some mmu page table
entries that map low physical memory to address 0xc0000000 and then
enable the mmu and jump to the virtual address.
It might be that you need to increase the size of that mapping.

        David

-- 
David Laight: david%l8s.co.uk@localhost