Date: Wed, 23 Mar 2011 20:02:00 +0000 From: Alexander Best <arundel@freebsd.org> To: Oliver Fromme <olli@lurza.secnetix.de> Cc: bz@FreeBSD.ORG, freebsd-arch@FreeBSD.ORG Subject: Re: kernel memory checks on boot vs. boot time Message-ID: <20110323200200.GA85810@freebsd.org> In-Reply-To: <201103231750.p2NHoSF6009826@lurza.secnetix.de> References: <20110323171443.GA59972@freebsd.org> <201103231750.p2NHoSF6009826@lurza.secnetix.de>
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On Wed Mar 23 11, Oliver Fromme wrote: > Alexander Best wrote: > > just as a side note: booting a kernel directly from boot stage 2 is broken on > > amd64. :( so there's no way around using the boot loader, which will cost extra > > time (even with autoboot_delay=0). > > > > so was the adbility to boot a kernel directly from boot2 abandoned? i heard > > reports it still works under i386. dunno about the other archs. > > The loader checks the type of the kernel binary (i386 vs > amd64). In case of amd64, it enables "long mode", among > other things. This is required for amd64, because the > kernel expects to be started in long mode. boot2 doesn't > do that, so you can't start an amd64 kernel directly from > boot2. hmm...i can't seem to find the location in loader/main.c. could you pinpoint me to the exact location? this is something i'd *really* like to try in amd64. cheers. alex > > In theory you could write a specialized amd64 variant of > boot2 that prepares the system for starting an amd64 kernel > directly. Whether there's enough space for that in boot2 > (8 KB) and whether it's worth the effort, I don't know. > > To be honest, I don't think that loader takes so much time. > When you set autoboot_delay="-1" and beastie_disable="YES", > the time spent in loader is negligible. (I'm assuming that > you also set BOOTWAIT=0 in make.conf, so boot2 doesn't wait > for a keypress either. I think the default is to wait 3 > seconds.) > > Best regards > Oliver > > > -- > Oliver Fromme, secnetix GmbH & Co. KG, Marktplatz 29, 85567 Grafing b. M. > Handelsregister: Registergericht Muenchen, HRA 74606, Geschäftsfuehrung: > secnetix Verwaltungsgesellsch. mbH, Handelsregister: Registergericht Mün- > chen, HRB 125758, Geschäftsführer: Maik Bachmann, Olaf Erb, Ralf Gebhart > > FreeBSD-Dienstleistungen, -Produkte und mehr: http://www.secnetix.de/bsd > > "[...] one observation we can make here is that Python makes > an excellent pseudocoding language, with the wonderful attribute > that it can actually be executed." -- Bruce Eckel -- a13x
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