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Date:      Tue, 19 Sep 2000 16:16:56 -0700
From:      Peter Wemm <peter@netplex.com.au>
To:        mjacob@feral.com
Cc:        Bruce Evans <bde@zeta.org.au>, Doug Rabson <dfr@nlsystems.com>, "Matthew N. Dodd" <mdodd@FreeBSD.org>, cvs-committers@FreeBSD.org, cvs-all@FreeBSD.org
Subject:   Re: cvs commit: src/sys/kern subr_bus.c 
Message-ID:  <200009192316.e8JNGuG32828@netplex.com.au>
In-Reply-To: <Pine.LNX.4.21.0009191049560.1923-100000@zeppo.feral.com> 

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Matthew Jacob wrote:
> 
> I'll second this.

Well, on the x86 we clear it twice, once in loader and once in locore.  I
thought it was redundant on the x86 since I thought the new boot2 cleared
the extended ELF segment sizes.  We do not support a.out kernels anymore
so the old bootblocks are not an issue.  (the old gas-1.9x cannot assemble
the .s files).

IMHO we should fix this bug in boot2.  It costs ~32 bytes.  (ie: reduces
from 212 bytes free to 180 bytes free).

For the Alpha this is irrelevant.  The loader clears bss and the loader
is the only bootstrap program.

Preserving x86 locore support the freebsd 1.1 bootblocks is silly, since
freebsd-1.1 could not load ELF kernels.  Supporting anything older than 3.1
bootblocks is a waste now since 3.1-R was the first release that shipped with
bootblocks than can load the present kernel.

> > > On Tue, 19 Sep 2000, Bruce Evans wrote:
> > 
> > > > The bss clearing code hasn't changed for years on  i386's.  I can't see
> > > > where the bss is cleared on alphas (alpha_init is called very early
> > > > in locore.s).
> > > 
> > > The bss is cleared by the loader for both x86 and alpha. I guess x86
> > > clears it again in locore but it doesn't need to.
> > 
> > It does need to, for compatibility with alternative loaders including boot2
> > and going back a long way (locore still has support for thr FreeBSD-1.1
> > boot blocks).
> > 
> > Bruce
> > 
> > 
> 
> 
> 

Cheers,
-Peter
--
Peter Wemm - peter@FreeBSD.org; peter@yahoo-inc.com; peter@netplex.com.au
"All of this is for nothing if we don't go to the stars" - JMS/B5



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