Date: Wed, 24 Oct 2007 17:44:16 -0400 From: John Baldwin <jhb@freebsd.org> To: src-committers@freebsd.org Cc: cvs-src@freebsd.org, cvs-all@freebsd.org Subject: Re: cvs commit: src/sys/sys gpt.h src/lib/libstand Makefile src/sbin/gpt Makefile add.c boot.c gpt.8 gpt.c gpt.h show.c src/sys/boot/common ufsread.c src/sys/boot/i386 Makefile src/sys/boot/i386/gptboot Makefile gptboot.c gptldr.S ... Message-ID: <200710241744.16811.jhb@freebsd.org> In-Reply-To: <200710242133.l9OLX05K085372@repoman.freebsd.org> References: <200710242133.l9OLX05K085372@repoman.freebsd.org>
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On Wednesday 24 October 2007 05:33:00 pm John Baldwin wrote:
> jhb 2007-10-24 21:33:00 UTC
>
> FreeBSD src repository
>
> Modified files:
> sys/sys gpt.h
> lib/libstand Makefile
> sbin/gpt Makefile add.c gpt.8 gpt.c gpt.h show.c
> sys/boot/common ufsread.c
> sys/boot/i386 Makefile
> sys/boot/i386/gptboot Makefile gptboot.c
> sys/boot/i386/libi386 biosdisk.c devicename.c
> sys/geom/part g_part.c g_part.h g_part_gpt.c
> Added files:
> sbin/gpt boot.c
> sys/boot/i386/gptboot gptldr.S
> sys/boot/i386/pmbr Makefile pmbr.s
> Log:
> First cut at support for booting a GPT labeled disk via the BIOS bootstrap
> on i386 and amd64 machines. The overall process is that /boot/pmbr lives
> in the PMBR (similar to /boot/mbr for MBR disks) and is responsible for
> locating and loading /boot/gptboot.
A quick way to use it is thus:
gpt create disk0
gpt boot disk0
-- use gpt add to add filesystems
-- newfs filesystems
-- populate filesystems
Some other notes:
- gptboot can not distinguish SCSI vs ATA disks since it has no bsdlabel to
peek into. However, since the loader reads /etc/fstab to determine the root
device, this doesn't actually matter.
- Currently the algorithm to find / is not very optimal. I've been talking
some with Marcel about this so this will probably change.
- ZFS + GPT booting shouldn't be that difficult to do now. It basically
requires two things:
1) A ZFS file system driver in libstand.
2) A gptboot that can read ZFS. This could either be a separate gptboot.zfs
or gptboot could be expanded to read both UFS and ZFS. Right now gptboot
is a little over 8k and the default size of the boot partition is 64k,
so there's a good bit of room there for read-only ZFS support.
- All the I/O for GPT disks uses EDD LBA with no C/H/S crap. Ever.
--
John Baldwin
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