Re: [PATCH v6 19/27] x86, boot: update comments about entries for64bit image

[H. Peter Anvin]

On 12/13/2012 04:13 PM, Yinghai Lu wrote:
> On Thu, Dec 13, 2012 at 3:27 PM, H. Peter Anvin <hpa@xxxxxxxxx> wrote:
> > On 12/13/2012 02:02 PM, Yinghai Lu wrote:
> > > +      * If we come here from a bootloader, kernel(text+data+bss+brk),
> > > +      * ramdisk, zero_page, command line could be above 4G.
> > > +      * We depend on an identity mapped page table being provided
> > > +      * that maps our entire kernel(text+data+bss+brk), and hopefully
> > > +      * all of memory.
> >
> > We should make it explicit what we depend on.  We certainly *can* depend
> > only on text+data+bss+brk ... with the dynamic page table approach we
> > can do that, and that would be most conservative; if we depend on other
> > things we should make that explicit, not just here but in boot.txt.
>
> yes, in my version, only need kernel(text+data+bss+brk) get mapped.
> aka the INIT_SIZE for decompressing.

It is definitely the minmum we can rely on, and so is the minimum we 
should rely on.  In fact, we don't even need .bss/.brk to be mapped, but 
we probably should require that as a matter of protocol.

	-hpa

--
H. Peter Anvin, Intel Open Source Technology Center
I work for Intel.  I don't speak on their behalf.

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/