Date: Fri, 11 Jul 2014 16:42:26 -0700 From: Nathan Whitehorn <nwhitehorn@freebsd.org> To: "Matthew D. Fuller" <fullermd@over-yonder.net> Cc: freebsd-current@freebsd.org Subject: Re: Boot loader too large Message-ID: <53C07662.6060200@freebsd.org> In-Reply-To: <20140711225043.GH50976@over-yonder.net> References: <CANuCnH9K_wSPkgrAzujDG5M72Uvuvj0ooNN%2BFFLUCFsvv6b7Ow@mail.gmail.com> <CANuCnH_TYf0e_4xgju5QgR4bKJ_j1td9JrfADuncR4RXu7ssnQ@mail.gmail.com> <201407111345.25225.jhb@freebsd.org> <53C06780.8010702@freebsd.org> <20140711225043.GH50976@over-yonder.net>
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On 07/11/14 15:50, Matthew D. Fuller wrote: > On Fri, Jul 11, 2014 at 03:38:56PM -0700 I heard the voice of > Nathan Whitehorn, and lo! it spake thus: >> I don't honestly remember where that number came from. It's at line >> 72 of usr.sbin/bsdinstall/partedit/partedit_x86.c. If 128 works >> better, I'm happy to change it, but it would be nice to know what >> the actual bounds here are before putting in a new arbitrary number. > src/sys/boot/i386/pmbr/pmbr.s says > > ------------- > next_boot:. incl (%si). . . # Next LBA > . . adcl $0,4(%si) > . . mov %es,%ax. . . # Adjust segment for next > . . addw $SECSIZE/16,%ax. . # sector > . . cmp $0x9000,%ax.. . # Don't load past 0x90000, > . . jae err_big. . . # 545k should be enough for > . . mov %ax,%es. . . # any boot code. :) > ------------- > > (err_big being printing the "Boot loader too large" message). Though > 0x90000 is actually 576k, not 545, but presumably there's some other > adjustment lopping off bits somewhere; that's 62 sectors diff. > > Regardless, I settled on 512k for my boot partitions (after finding > the above error when I previously decided "it's a few dozen k, I'll > just set aside a meg to be safe" and then discovered the whole > "not-booting" thing that caused. > > I bumped it to 512K. Thanks! -Nathan
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