cvs commit: src/sys/i386/i386 locore.s

[Bruce Evans]

On Wed, 30 Jul 2003, Ruslan Ermilov wrote:

> On Tue, Jul 29, 2003 at 02:57:01PM -0700, Bruce Evans wrote:
> > bde         2003/07/29 14:57:01 PDT
> >
> >   FreeBSD src repository
> >
> >   Modified files:
> >     sys/i386/i386        locore.s
> >   Log:
> >   Restored clearing of the bss, except for putting it in a correct place
> >   with up to date comments.  This fixes booting kernels with boot2
> >   (except for loss of the features provided by loader) and is suitable
> >   for MFC.  Contrary to the old comments, most loaders don't clear the bss.
> >   biosboot lost clearing of the bss in a code crunch in 1997, and boot2
> >   never did it.
> >
> To make it crystal clear, it does mean that we can (once again) boot
> kernels without loader(8) on i386, correct?

Almost.  There are still the following problems:

Symbols will be missing unless you use my hack for faking some module
data (I still haven't de-magiced it).  But symbols don't seem to be
needed as much as they used to.  I didn't notice them missing when I
tested this.

if you do use my hack, then you need to use an old version of boot2,
since boot2 in -current lost its RB_BOOTINFO flag so it doesn't actually
pass the historical bootinfo extensions that it spends a lot of space
to set up, and my hack and/or the preload_metadata handler is fragile
and causes panics if the symbol table is empty.  I think the problem
is that a real symbol table is never empty.  Other things in the extended
bootinfo are not needed, at least for me.

Statically configured hints and environment are needed of course.

Bruce