Still possible to directly boot without loader?

[Ruslan Ermilov]

On Thu, Oct 26, 2006 at 03:42:34PM -0400, John Baldwin wrote:
> On Thursday 26 October 2006 15:18, Ruslan Ermilov wrote:
> > On Thu, Oct 26, 2006 at 11:38:24AM -0400, John Baldwin wrote:
> > > On Thursday 26 October 2006 10:42, Ruslan Ermilov wrote:
> > > > On Thu, Oct 26, 2006 at 10:28:09AM -0400, John Baldwin wrote:
> > > > > boot2 should do whatever loader does.
> > > > > 
> > > > But this would be a regression, since loader(8) does the following,
> > > > in the ELF32 case:
> > > > 
> > > > : 0 edoofus:ttyp2:/sys/boot/i386/libi386 >grep -w entry elf32_freebsd.c
> > > > :     vm_offset_t                 entry, bootinfop, modulep, kernend;
> > > > :     entry = ehdr->e_entry & 0xffffff;
> > > > :     printf("Start @ 0x%lx ...\n", entry);
> > > > :     __exec((void *)entry, boothowto, bootdev, 0, 0, 0, bootinfop, modulep, kernend);
> > > 
> > > Ah, ok.  Make them both just mask the top 8 bits then. :)
> > > 
> > OK, I backed out your change to boot2.c.
> 
> Sorry, I meant that both boot2 and loader should follow your proposal of masking 28 bits.
> Just masking the top 4 bits is probably sufficient.
> 
:-)

OK, I'll craft a patch tomorrow.  This will also require patching at least
sys/boot/common/load_elf.c:__elfN(loadimage), maybe something else.
I think we could actually mask 30 bits; that would allow to load 1G kernels,
provided that sufficient memory exists.


Cheers,
-- 
Ruslan Ermilov
ru at FreeBSD.org
FreeBSD committer
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