Having the table in the 'standard' mbr allows fdisk to write in bootsel
menu items and only ask about updating the mbr code before exit.
Sysinst validates that the mbr code contains the bootselect table for
all the mbr code variants it reads - because it might want to write the table
and doesn't really want to make the validation dependant on what it is
going to do later.
Fixes install/25235, but sysinst needs some changes (like reporting the
failure to write the mbr) before the pr itself is closed.
leave 4 bytes for the Windows NT Drive Serial Number (DSN) at 440-443
(as mbr_sector.mbr_dsn).
Ensure that all the MBR & PBR code reserves space for mbr_sector.mbr_dsn.
Leave the bootsel magic number at 444-445 as mbr_sector.mbr_bootsel_magic
(instead of mbr_sector.mbr_bootsel.mbrbs_magic), but use 0xb5e1 (MBR_BS_MAGIC)
instead of 0xaa55 (MBR_MAGIC) to indicate that this change has occurred.
Rework MBR_BS_NEWMBR to mean "mbr_bootsel has moved to 400".
Modify fdisk(8) to automatically relocate the mbr_bootsel from 404 to 400
if mbr_bootsel_magic is the old value (0xaa55), and unset MBR_BS_NEWMBR
to flag that new mbr_bootsel code must be used if updating the MBR.
These changes fixes a problem where Windows 2000 or Windows XP would corrupt
the last 3 bytes + NUL of MBR partition 3's bootsel name if the bootsel name
was 5 characters long, replacing bytes 6-9 with the DSN.
Also, by explicitly reserving the space for the DSN we prevent problems in the
future if non bootsel MBR or PBR code had other information at bytes 440-443.
(it only allowed to boot an nfs /netbsd automatically)
To make it work for people who can't tell the DHCP server to pass
the right kernel file to pxeboot, without losing flexibility for
people who can, do the following:
Use the filename given by the DHCP server if it contains a ":". A ":"
was already used to seperate filesystem and filename, so we don't
lose anything. Otoh, a path to pxeboot usually doesn't contain a ":",
so it should still work if we got the old pxeboot filename again.
make absolutely high the top 16bits of returned values are zero.
Ralf's list says that some BIOS need %eax = 0x0000e820 in getmementry.
Add a few comments.
Might fix problems with memory size detection on some systems.
FAT16 (11+51) except when booting from FAT{12,16,32}, which needs FAT32 (11+79).
We still reserve the BPB for non-bootxx_msdos PBR bootblocks because
they may be installed as a floppy boot record (and those need a BPB).
Remove some redundant wording in an error messsage, saving 6 bytes.
i386-MD installboot.
They haven't been enabled for a while, keeping them here is just
confusing, and they're still going to be in the CVS repo attic...
<sys/bootblock.h>:
* Added definitions for the Master Boot Record (MBR) used by
a variety of systems (primarily i386), including the format
of the BIOS Parameter Block (BPB).
This information was cribbed from a variety of sources
including <sys/disklabel_mbr.h> which this is a superset of.
As part of this, some data structure elements and #defines
were renamed to be more "namespace friendly" and consistent
with other bootblocks and MBR documentation.
Update all uses of the old names to the new names.
<sys/disklabel_mbr.h>:
* Deprecated in favor of <sys/bootblock.h> (the latter is more
"host tool" friendly).
amd64 & i386:
* Renamed /usr/mdec/bootxx_dosfs to /usr/mdec/bootxx_msdos, to
be consistent with the naming convention of the msdosfs tools.
* Removed /usr/mdec/bootxx_ufs, as it's equivalent to bootxx_ffsv1
and it's confusing to have two functionally equivalent bootblocks,
especially given that "ufs" has multiple meanings (it could be
a synonym for "ffs", or the group of ffs/lfs/ext2fs file systems).
* Rework pbr.S (the first sector of bootxx_*):
+ Ensure that BPB (bytes 11..89) and the partition table
(bytes 446..509) do not contain code.
+ Add support for booting from FAT partitions if BOOT_FROM_FAT
is defined. (Only set for bootxx_msdos).
+ Remove "dummy" partition 3; if people want to installboot(8)
these to the start of the disk they can use fdisk(8) to
create a real MBR partition table...
+ Compile with TERSE_ERROR so it fits because of the above.
Whilst this is less user friendly, I feel it's important
to have a valid partition table and BPB in the MBR/PBR.
* Renamed /usr/mdec/biosboot to /usr/mdec/boot, to be consistent
with other platforms.
* Enable SUPPORT_DOSFS in /usr/mdec/boot (stage2), so that
we can boot off FAT partitions.
* Crank version of /usr/mdec/boot to 3.1, and fix some of the other
entries in the version file.
installboot(8) (i386):
* Read the existing MBR of the filesystem and retain the BIOS
Parameter Block (BPB) in bytes 11..89 and the MBR partition
table in bytes 446..509. (Previously installboot(8) would
trash those two sections of the MBR.)
mbrlabel(8):
* Use sys/lib/libkern/xlat_mbr_fstype.c instead of homegrown code
to map the MBR partition type to the NetBSD disklabel type.
Test built "make release" for i386, and new bootblocks verified to work
(even off FAT!).
