Date: Tue, 19 Sep 2000 16:15:59 -0700 (PDT) From: Matthew Jacob <mjacob@feral.com> To: Peter Wemm <peter@netplex.com.au> 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: <Pine.LNX.4.21.0009191615080.2569-100000@zeppo.feral.com> In-Reply-To: <200009192316.e8JNGuG32828@netplex.com.au>
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It's more a matter of what should a standalone executive program assume about an environment. In my opinion, it's safer to not assume bss clearing by your loader. > > > > 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 > To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe cvs-all" in the body of the message
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