Date: Sun, 19 Sep 2004 00:08:50 +0200 From: "Poul-Henning Kamp" <phk@phk.freebsd.dk> To: John Baldwin <jhb@FreeBSD.org> Cc: cvs-all@FreeBSD.org Subject: Re: cvs commit: src/sys/boot/i386/boot2 boot2.c Message-ID: <15147.1095545330@critter.freebsd.dk> In-Reply-To: Your message of "Sat, 18 Sep 2004 16:59:48 EDT." <200409181659.48310.jhb@FreeBSD.org>
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In message <200409181659.48310.jhb@FreeBSD.org>, John Baldwin writes: >On Saturday 18 September 2004 03:08 am, Poul-Henning Kamp wrote: >> In message <200409180207.i8I27044010045@repoman.freebsd.org>, John Baldwin >> writ >> >> es: >> >jhb 2004-09-18 02:07:00 UTC >> > >> > FreeBSD src repository >> > >> > Modified files: >> > sys/boot/i386/boot2 boot2.c >> > Log: >> > A long, long time ago in a CVS branch far away (specifically, HEAD prior >> > to 4.0 and RELENG_3), the BTX mini-kernel used paging rather than flat >> > mode and clients were limited to a virtual address space of 16 >> > megabytes. Because of this limitation, boot2 silently masked all physical >> > addresses in any binaries it loaded so that they were always loaded into >> > the first 16 Meg. Since BTX no longer has this limitation (and hasn't >> > for a long time), remove the masking from boot2. This allows boot2 to >> > load kernels larger than about 12 to 14 meg (12 for non-PAE, 14 for PAE). >> >> Does this also give us better space for isa_dma bounce buffers ? > >Err, I don't see how it could. This only affects how boot2 handles addresses >in the executables it loads, it doesn't affect how the kernel manages memory >at all. it was the "so that they were always loaded into the first 16 Meg" that triggered a neuron here. We're seeing isa-dma bounce buffers getting hard to get hold of these days. -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 phk@FreeBSD.ORG | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence.
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