 @@ -1,862 +1,873 @@
-.\"	$NetBSD: boot.8,v 1.11.4.4 2019/09/18 17:30:05 martin Exp $
+.\"	$NetBSD: boot.8,v 1.11.4.5 2020/07/15 15:54:50 martin Exp $
 .\"
 .\" Copyright (c) 1991, 1993
 .\"	The Regents of the University of California.  All rights reserved.
 .\"
 .\" This code is derived from software written and contributed
 .\" to Berkeley by William Jolitz.
 .\"
 .\" Redistribution and use in source and binary forms, with or without
 .\" modification, are permitted provided that the following conditions
 .\" are met:
 .\" 1. Redistributions of source code must retain the above copyright
 .\"    notice, this list of conditions and the following disclaimer.
 .\" 2. Redistributions in binary form must reproduce the above copyright
 .\"    notice, this list of conditions and the following disclaimer in the
 .\"    documentation and/or other materials provided with the distribution.
 .\" 3. Neither the name of the University nor the names of its contributors
 .\"    may be used to endorse or promote products derived from this software
 .\"    without specific prior written permission.
 .\"
 .\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 .\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 .\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 .\" ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 .\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 .\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 .\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 .\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 .\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 .\" SUCH DAMAGE.
 .\"
 .\"     @(#)boot_i386.8	8.2 (Berkeley) 4/19/94
 .\"
-.Dd September 13, 2019
+.Dd July 15, 2020
 .Dt BOOT 8 x86
 .Os
 .Sh NAME
 .Nm boot
 .Nd
 system bootstrapping procedures
 .Sh DESCRIPTION
 Intel Architecture, 32-bit (IA-32) computers (the
 .Tn IBM PC
 and its clones)
 that can run
 .Nx Ns /i386
 or
 .Nx Ns /amd64
 can use any of the following boot procedures, depending on what the hardware and
 .Tn BIOS
 support:
 .Bl -tag -width "x86/pxeboot(8)"
 .It boot
 bootstrap
 .Nx
 from the system
 .Tn BIOS
 .It efiboot
 bootstrap
 .Nx
 from the system
 .Tn UEFI
 .It Xr x86/dosboot 8
 bootstrap
 .Nx
 from
 .Tn MS-DOS
 .It Xr x86/pxeboot 8
 network bootstrap
 .Nx
 from a
 .Tn TCP/IP
 .Tn LAN
 with
 .Tn DHCP ,
 .Tn TFTP ,
 and
 .Tn NFS .
 .El
 .Ss Power fail and crash recovery
 Normally, the system will reboot itself at power-up or after crashes.
 An automatic consistency check of the file systems will be performed,
 and unless this fails, the system will resume multi-user operations.
 .Ss Cold starts
 The 386
 .Tn "PC AT"
 clones attempt to boot the floppy disk drive A (otherwise known as drive
 ) first, and failing that, attempt to boot the hard disk C (otherwise
 known as hard disk controller 1, drive 0).
 The
 .Nx
 bootblocks are loaded and started either by the
 .Tn BIOS ,
 or by a boot selector program (such as OS-BS, BOOTEASY, the OS/2 Boot Menu or
 .Nx Ns 's
 .No boot-selecting
 master boot record - see
 .Xr x86/mbr 8 ) .
 .Ss Normal Operation
 Once running, a banner similar to the following will appear:
 .Bd -unfilled -offset indent
 >> NetBSD BIOS Boot, revision 3.0
 >> (user@buildhost, builddate)
 >> Memory: 637/15360 k
 Press return to boot now, any other key for boot menu
 booting hd0a:netbsd - starting in 5
 .Ed
 .Pp
 After a countdown, the system image listed will be loaded.
 In the example above, it will be
 .Dq Li hd0a:netbsd
 which is the file
 .Pa /netbsd
 on partition
 .Dq a
 of the
 .Nx
 .Tn MBR
 partition of the first hard disk known to the
 .Tn BIOS
 .Po
 which is an
 .Tn IDE
 or similar device - see the
 .Sx BUGS
 section
 .Pc .
 .Pp
 Pressing a key within the time limit, or before the boot program starts, will
 enter interactive mode.
 When using a short or 0 timeout, it is often useful to interrupt the boot
 by holding down a shift key, as some BIOSes and BIOS extensions will drain the
 keystroke buffer at various points during POST.
 .Pp
 If present, the file
 .Pa /boot.cfg
 will be used to configure the behaviour of the boot loader including
 setting the timeout, choosing a console device, altering the banner
 text and displaying a menu allowing boot commands to be easily chosen.
 See
 .Xr boot.cfg 5 .
 .Ss Boot Protocol
 The
 .Nx Ns /x86
 boot loader can boot a kernel using either the native
 .Nx
 boot protocol, or the
 .Dq multiboot
 protocol (which is compatible with some other operating systems).
 In the native
 .Nx
 boot protocol, options are passed from the boot loader
 to the kernel via flag bits in the
 .Va boothowto
 variable (see
 .Xr boothowto 9 ) .
 In the multiboot protocol, options are passed from the boot loader
 to the kernel as strings.
 .Ss Diagnostic Output
 If the first stage boot fails to load the boot, it will print a terse
 message indicating the reason for the failure.
 The possible error messages and their cause are listed in
 .Xr x86/mbr 8 .
 .Pp
 If the first stage boot succeeds, the banner will be shown and the
 error messages should be self-explanatory.
 .Ss Interactive mode
 In interactive mode, the boot loader will present a prompt, allowing
 input of these commands:
 .\" NOTE: much of this text is duplicated in the MI boot.8.
 .\" Some of it is
 .\" also duplicated in the x86-specific x86/dosboot.8 and x86/pxeboot.8;
 .\" please try to keep all relevant files synchronized.
 .Bl -tag -width 04n -offset 04n
 .It Ic boot Oo Va device : Oc Ns Oo Va filename Oc Oo Fl 1234abcdmqsvxz Oc
 The default
 .Va device
 will be set to the disk from which the boot loader was loaded.
 The partition is set to the first match in this list:
 .Bl -enum -compact
 .It
 The first
 .Xr gpt 8
 partition with the
 .Va bootme
 attribute set.
 .It
 The partition from which the boot loader was loaded from, if that
 can be detected.
 .It
 The first partition with a file system that could be bootable.
 .It
 The first partition.
 .El
 To boot from an alternate disk, the full name of the device should
 be given at the prompt.
 .Va device
 is of the form
 .Va NAME=partition_label
 when booting from a
 .Xr gpt 8
 partitioned disk.
 Otherwise, the syntax is
 .Xo Va xd
 .Op Va N Ns Op Va x
 .Xc
 where
 .Va xd
 is the device from which to boot,
 .Va N
 is the unit number, and
 .Va x
 is the partition letter.
 .Pp
 In the later case, the following list of supported devices may
 vary from installation to installation:
 .Pp
 .Bl -hang -compact
 .It hd
 Hard disks as numbered by the BIOS.
 This includes ST506, IDE, ESDI, RLL disks on a WD100[2367] or
 lookalike controller(s), and SCSI disks
 on SCSI controllers recognized by the BIOS.
 .It fd
 Floppy drives as numbered by the BIOS.
 .It cd
 CD-ROM drives as numbered by the BIOS.
 .It raid
 RAIDframe configured from hard disks recognized by the BIOS.
 Only RAID level 1 sets are supported by bootstrap code.
 If the RAID is partitioned, the first partition is used, or the
 first
 .Xr gpt 8
 partition that has the
 .Va bootme
 attribute set.
 Inner RAIDframe partitions can also be given to the
 .Ic dev
 command using he
 .Va NAME=partition_label
 syntax.
 .El
 .Pp
 The default
 .Va filename
 is
 .Pa netbsd ;
 if the boot loader fails to successfully
 open that image, it then tries
 .Pa netbsd.gz
 (expected to be a kernel image compressed by gzip), followed by
 .Pa netbsd.old ,
 .Pa netbsd.old.gz ,
 .Pa onetbsd ,
 and finally
 .Pa onetbsd.gz .
 Alternate system images can be loaded by just specifying the name of the image.
 .Pp
 Options are:
 .Bl -tag -width xxx
 .It Fl 1
 Sets the machine-dependent flag
 .Sy RB_MD1
 in
 .Va boothowto .
 In
 .Nx Ns /x86 ,
 this disables multiprocessor boot;
 the kernel will boot in uniprocessor mode.
 .It Fl 2
 Sets the machine-dependent flag
 .Sy RB_MD2
 in
 .Va boothowto .
 In
 .Nx Ns /x86 ,
 this disables ACPI.
 .It Fl 3
 Sets the machine-dependent flag
 .Sy RB_MD3
 in
 .Va boothowto .
 In
 .Nx Ns /x86 ,
 this has no effect.
 .It Fl 4
 Sets the machine-dependent flag
 .Sy RB_MD4
 in
 .Va boothowto .
 In
 .Nx Ns /x86 ,
 this has no effect.
 .It Fl a
 Sets the
 .Sy RB_ASKNAME
 flag in
 .Va boothowto .
 This causes the kernel to prompt for the root file system device,
 the system crash dump device, and the path to
 .Xr init 8 .
 .It Fl b
 Sets the
 .Sy RB_HALT
 flag in
 .Va boothowto .
 This causes subsequent reboot attempts to halt instead of rebooting.
 .It Fl c
 Sets the
 .Sy RB_USERCONF
 flag in
 .Va boothowto .
 This causes the kernel to enter the
 .Xr userconf 4
 device configuration manager as soon as possible during the boot.
 .Xr userconf 4
 allows devices to be enabled or disabled, and allows device locators
 (such as hardware addresses or bus numbers)
 to be modified before the kernel attempts to attach the devices.
 .It Fl d
 Sets the
 .Sy RB_KDB
 flag in
 .Va boothowto .
 Requests the kernel to enter debug mode, in which it
 waits for a connection from a kernel debugger; see
 .Xr ddb 4 .
 .It Fl m
 Sets the
 .Sy RB_MINIROOT
 flag in
 .Va boothowto .
 Informs the kernel that a mini-root file system is present in memory.
 .It Fl q
 Sets the
 .Sy AB_QUIET
 flag in
 .Va boothowto .
 Boot the system in quiet mode.
 .It Fl s
 Sets the
 .Sy RB_SINGLE
 flag in
 .Va boothowto .
 Boot the system in single-user mode.
 .It Fl v
 Sets the
 .Sy AB_VERBOSE
 flag in
 .Va boothowto .
 Boot the system in verbose mode.
 .It Fl x
 Sets the
 .Sy AB_DEBUG
 flag in
 .Va boothowto .
 Boot the system with debug messages enabled.
 .It Fl z
 Sets the
 .Sy AB_SILENT
 flag in
 .Va boothowto .
 Boot the system in silent mode.
 .El
-.It Ic consdev Va dev
+.It Ic consdev Va dev Ns Oo Ns , Ns Va speed Oc
 Immediately switch the console to the specified device
 .Va dev
 and reprint the banner.
 .Va dev
 must be one of
 .\" .Bl -item -width com[0123]kbd -offset indent -compact
 .Ar pc , com0 , com1 , com2 ,
 .Ar com3 , com0kbd , com1kbd , com2kbd ,
 .Ar com3kbd ,
 or
 .Ar auto .
 See
 .Sx Console Selection Policy
 in
 .Xr x86/boot_console 8 .
 .Pp
+A
 .Va speed
 for the serial port is optional and defaults to 9600.
 If a value of zero is specified, then the current baud rate (set by the
 BIOS) will be used.
 Setting the
 .Va speed
 with the
 .Ar pc
 device is not possible.
 .It Ic dev Op Va device
 Set the default drive and partition for subsequent file system
 operations.
 Without an argument, print the current setting.
 .Va device
 is of the form specified in
 .Cm boot .
 .It Ic fs Va file
 Load a file system image from the specified
 .Ar file ,
 and request the kernel to use it as the root file system.
 The
 .Xr makefs 8
 utility may be used to create suitable file system images.
 .It Ic help
 Print an overview about commands and arguments.
 .It Ic load Va module Op Ar arguments
 Load the specified kernel
 .Va module ,
 and pass it the specified
 .Ar arguments .
 If the module name is not an absolute path,
 .Pa /stand/ Xo Ns
 .Aq Sy arch Ns
 .Pa / Ns
 .Aq Sy osversion Ns
 .Pa /modules/ Ns
 .Aq Sy module Ns
 .Pa / Ns
 .Aq Sy module Ns
 .Pa .kmod
 .Xc
 is used.
 Possible uses of the
 .Ic load
 command include loading a memory disk image before booting a kernel,
 or loading a
 .Tn Xen
 DOM0 kernel before booting the
 .Tn Xen
 hypervisor.
 See
 .Xr boot.cfg 5
 for examples.
 .Pp
 In addition to the
 .Cm boot
 options specified above, the
 .Tn Xen
 DOM0 kernel accepts
 .Po Ar arguments
 being separated with spaces
 .Pc :
 .Bl -tag -width xxx
 .It Ic bootdev Ns = Ns Ar dev Po or Ic root Ns = Ns Ar dev Pc
 Override the default boot device.
 .Ar dev
 is of the form
 .Va NAME=partition_label
 for
 .Xr gpt 8
 partitionned disks. It can also be a unit name
 .Po Dq wd0
 .Pc ,
 or an interface name
 .Po Dq bge0 ,
 .Dq wm0 ,
 \&...
 .Pc
 for cases where the root file system has to be loaded
 from network (see the
 .Sx BUGS
 section in
 .Xr x86/pxeboot 8 ) .
 .It Ic console Ns = Ns Ar dev
 Console used by DOM0 kernel during boot.
 .Ar dev
 accepts the same values as the ones given for the
 .Cm consdev
 command.
 See
 .Sx Console Selection Policy
 in
 .Xr x86/boot_console 8 .
 .It Xo Ic ip Ns = Ns
 .Ar my_ip Ns : Ns Ar serv_ip Ns : Ns Ar gw_ip Ns : Ns
 .Ar mask Ns : Ns Ar host Ns : Ns Ar iface
 .Xc
 Specify various parameters for a network boot (IPs are in
 dot notation),
 each one separated by a colon:
 .Bl -tag -width xxxxxxx
 .It Va my_ip
 address of the host
 .It Va serv_ip
 address of the NFS server
 .It Va gw_ip
 address of the gateway
 .It Va mask
 network mask
 .It Va host
 address of the host
 .It Va iface
 interface
 .Po e.g., Dq xennet0
 or
 .Dq eth0
 .Pc
 .El
 .It Ic nfsroot Ns = Ns Ar address Ns : Ns Ar rootpath
 Boot the system with root on NFS.
 .Ar address
 is the address of the NFS server, and
 .Ar rootpath
 is the remote mount point for the root file system.
 .It Ic pciback.hide Ns = Ns Ar pcidevs
 Pass a list of PCI IDs for use with the PCI backend driver,
 .Xr pciback 4 .
 .Ar pcidevs
 is formed of multiple IDs (in bus:device.function notation),
 each ID being surrounded with brackets.
 PCI domain IDs are currently ignored.
 See
 .Xr pciback 4 .
 .El
 .It Ic ls Op Pa path
 Print a directory listing of
 .Pa path ,
 containing inode number, filename, and file type.
 .Pa path
 can contain a device specification.
 .It Ic menu
 Display the boot menu and initiate a countdown,
 similarly to what would have happened if interactive mode
 had not been entered.
 .It Ic modules Bro Ar on | off | enabled | disabled Brc
 The values
 .Ar enabled , on
 will enable module loading for
 .Cm boot
 and
 .Cm multiboot ,
 whereas
 .Ar disabled , off
 will turn off the feature.
 .It Ic multiboot Va kernel Op Ar arguments
 Boot the specified
 .Va kernel ,
 using the
 .Dq multiboot
 protocol instead of the native
 .Nx
 boot protocol.
 The
 .Va kernel
 is specified in the same way as with the
 .Ic boot
 command.
 .Pp
 The multiboot protocol may be used in the following cases:
 .Bl -tag -width indent
 .It Nx Ns / Ns  Xen No kernels
 The
 .Tn Xen
 DOM0 kernel must be loaded as a module using the
 .Ic load
 command, and the
 .Tn Xen
 hypervisor must be booted using the
 .Ic multiboot
 command.
 Options for the DOM0 kernel (such as
 .Dq -s
 for single user mode) must be passed as options to the
 .Ic load
 command.
 Options for the hypervisor (such as
 .Dq dom0_mem=256M
 to reserve 256 MB of memory for DOM0)
 must be passed as options to the
 .Ic multiboot
 command.
 See
 .Xr boot.cfg 5
 for examples on how to boot
 .Nx Ns / Ns  Xen.
 .It Nx No multiboot kernels
+A
 .Nx
 kernel that was built with
 .Cd options MULTIBOOT
 (see
 .Xr x86/multiboot 8 )
 may be booted with either the
 .Ic boot
 or
 .Ic multiboot
 command, passing the same
 .Ar arguments
 in either case.
 .It Non- Ns Nx No kernels
 A kernel for a
 .No non- Ns Nx
 operating system that expects to be booted using the
 multiboot protocol (such as by the GNU
 .Dq GRUB
 boot loader)
 may be booted using the
 .Ic multiboot
 command.
 See the foreign operating system's documentation for the available
 .Ar arguments .
 .El
 .It Ic quit
 Reboot the system.
 .It Ic rndseed Ar file
 Load the specified
 .Ar file
 and request the kernel to use it as a seed for the
 .Xr rnd 4
 random number generator.
 The
 .Ar file
 should be in the private format used by
 .Xr rndctl 8 ,
 and should have been saved by
 .Ql "rndctl -S"
 shortly before the previous shutdown.
 See the
 .Va random_seed
 and
 .Va random_file
 variables in
 .Xr rc.conf 5 ,
 and the
 .Pa /etc/rc.d/random_seed
 script, for a way to manage the seed file.
 Using the same seed file on more then one host,
 or for more than one boot on the same host,
 will reduce the quality of random numbers
 and may impact system security.
 .It Ic userconf Va command
 Pass command
 .Va command
 to
 .Xr userconf 4
 at boot time.
 These commands are processed before the interactive
 .Xr userconf 4
 shell is executed, if requested.
 .It Ic splash Ar file
 Load a graphical image from the specified
 .Ar file
 and request the kernel to use it as a splash screen.
 The
 .Ar file
 should contain an image in one of these formats:
 JPEG (baseline only, not progressive),
 PNG (8-bit only),
 TGA,
 BMP (non-1bpp, non-RLE),
 GIF,
 PSD (composited view only),
 or
 PIC.
 .It Ic vesa Bro Va modenum | Ar on | off | enabled | disabled | list Brc
 Initialise the video card to the specified resolution and bit depth.
 The
 .Va modenum
 should be in the form of
 .Ar 0x100 , 800x600 , 800x600x32 .
 The values
 .Ar enabled , on
 put the display into the default mode, and
 .Ar disabled , off
 returns the display into standard vga mode.
 The value
 .Ar list
 lists all supported modes.
 .El
 .Pp
 In an emergency, the bootstrap methods described in the
 .Nx
 installation notes for the x86 architectures
 can be used to boot from floppy or other media,
 or over the network.
 .Ss Locating the root file system
 The kernel uses information from the bootloader to locate the
 file system to mount as root.
 There are three methods:
 .Bl -tag -width 04n -offset 04n
 .It Ic BTINFO_ROOTDEVICE Va from
 .Xr boot.cfg 5
 or multiboot.
 The bootloader passes the root device name as driver, unit, and
 partition (like sd0a).
 This will be automatically substituted by a
 .Xr dk 4
 wedge if one is discovered.
 .Pp
 The bootloader passes a wedge name as "wedge:" followed by the name.
 The kernel will search for a
 .Xr dk 4
 device with that name.
 .It Ic BTINFO_BOOTWEDGE Va determined by bootblock
 The bootloader passes start offset and length of a hard disk partition
 and a offset, size and hash of a "boot area".
 Then kernel searches
 all disks and wedges for a block sequence at that offset with a
 matching hash.
 If one is found, the kernel will look for a wedge
 on that device at the same offset.
 .Pp
 An additional partition number is provided if the bootloader also
 passed a BTINFO_BOOTDISK record.
 This (or partition 'a') will be used
 by the kernel as a fallback if there is no matching wedge.
 .It Ic BTINFO_BOOTDISK Va determined by bootblock
 This uses the device number passed by the BIOS that
 distinguishes between floppy, hard drive and CD-ROM boot.
 .Bl -tag -width xxx
 .It Ic Floppy
 The kernel searches for the
 .Xr fd 4
 device with the correct unit, the partition number is used
 to select a specific disk format.
 See
 .Xr fd 4
 for details.
 .It Ic Hard drive
 The bootloader passed a partition number and disklabel
 data (offset, type, checksum, packname).
 The kernel searches
 all disks for a matching disklabel.
 If one is found, the
 kernel will use that device and partition number.
 .It Ic CDROM
 The BIOS does not distinguish between multiple CD devices.
 The kernel searches for the first
 .Xr cd 4
 device.
 So you can only boot from unit 0.
 .El
 .El
 .Sh FILES
 .Bl -tag -width /usr/mdec/bootxx_fstype -compact
 .It Pa /boot
 boot program code loaded by the primary bootstrap
 .It Pa /boot.cfg
 optional configuration file
 .It Pa /netbsd
 system code
 .It Pa /netbsd.gz
 gzip-compressed system code
 .It Pa /usr/mdec/boot
 master copy of the boot program (copy to /boot)
 .It Pa /usr/mdec/bootxx_fstype
 primary bootstrap for file system type fstype, copied to the start of
 the
 .Nx
 partition by
 .Xr installboot 8 .
 .It Pa /usr/mdec/bootia32.efi
 .It Pa /usr/mdec/bootx64.efi
 .Tn UEFI
 bootstraps for
 .Nx Ns /i386
 and
 .Nx Ns /amd64 ,
 which should be copied to the
 .Pa /efi/boot
 directory in a
 .Tn FAT
 formatted partition of type
 .Tn EFI
 (Either
 .Xr mbr 8
 and
 .Xr gpt 8 ,
 see the
 .Sx BUGS
 section).
 .Nx
 .Tn UEFI
 bootstrap reads its configuration from the
 .Pa /efi/netBSD/boot.cfg
 file in the
 .Tn EFI
 partition.
 .El
 .Sh SEE ALSO
 .Xr ddb 4 ,
 .Xr fd 4 ,
 .Xr pciback 4 ,
 .Xr userconf 4 ,
 .Xr boot.cfg 5 ,
 .Xr halt 8 ,
 .Xr installboot 8 ,
 .Xr reboot 8 ,
 .Xr rescue 8 ,
 .Xr shutdown 8 ,
 .Xr x86/boot_console 8 ,
 .Xr x86/dosboot 8 ,
 .Xr x86/mbr 8 ,
 .Xr x86/multiboot 8 ,
 .Xr x86/pxeboot 8 ,
 .Xr boothowto 9
 .Sh BUGS
 The kernel file name must be specified before, not after, the boot options.
 Any
 .Ar filename
 specified after the boot options, e.g.:
 .Pp
 .Bd -unfilled -offset indent -compact
 .Cm boot -d netbsd.test
 .Ed
 .Pp
 is ignored, and the default kernel is booted.
 .Pp
 Hard disks are always accessed by
 .Tn BIOS
 functions.
 Unit numbers are
 .Tn BIOS
 device numbers which might differ from numbering in the
 .Nx
 kernel or physical parameters
 .Po
 e.g.,
 .Tn SCSI
 slave numbers
 .Pc .
 There isn't any distinction between
 .Dq sd
 and
 .Dq wd
 devices at the bootloader level.
 This is less a bug of the bootloader code than
 a shortcoming of the PC architecture.
 The default disk device's name printed in the starting message
 is derived from the
 .Dq type
 field of the
 .Nx
 disklabel (if it is a hard disk).
 .Pp
 .Tn UEFI
 implementation are supposed to support either
 .Xr mbr 8
 or
 .Xr gpt 8
 partitionning, but some do not handle the later.
 .Tn UEFI
 Booting
 from a
 .Xr gpt 8
 partitioned disk is still possible in this case, by adding
 an overlapping
 .Tn EFI
 partition in the protective
 .Xr mbr 8
 block.
 This can be achieved using the following commands
 (you must adapt the hard disk and
 .Tn EFI
 partition start end size to fit your setup):
 .Dl Ic dd if=/dev/rwd0d bs=512 count=1 of=mbr
 .Dl Ic fdisk -FIfaui1s 4/34/32768 -c /usr/mdec/mbr mbr
 .Dl Ic dd if=mbr bs=512 count=1 of=/dev/rwd0d conv=notrunc
 The resulting
 .Xr mbr 8
 partition table will look like this:
 .Bd -unfilled -offset indent
 : GPT Protective MBR (sysid 238)
     start 1, size 2097151 (1024 MB, Cyls 0-130/138/8)
         PBR is not bootable: Bad magic number (0x0000)
 : Primary DOS with 16 bit FAT <32M (sysid 4)
     start 34, size 32768 (16 MB, Cyls 0/0/35-2/10/42), Active
 : <UNUSED>
 : <UNUSED>
 .Ed

 @@ -1,618 +1,636 @@
-/*	$NetBSD: boot2.c,v 1.66.10.1 2019/09/17 18:26:53 martin Exp $	*/
+/*	$NetBSD: boot2.c,v 1.66.10.2 2020/07/15 15:54:50 martin Exp $	*/
 /*-
  * Copyright (c) 2008, 2009 The NetBSD Foundation, Inc.
  * All rights reserved.
+ *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
  *    documentation and/or other materials provided with the distribution.
+ *
  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  * POSSIBILITY OF SUCH DAMAGE.
  */
 /*
  * Copyright (c) 2003
  *	David Laight.  All rights reserved
  * Copyright (c) 1996, 1997, 1999
  * 	Matthias Drochner.  All rights reserved.
  * Copyright (c) 1996, 1997
  * 	Perry E. Metzger.  All rights reserved.
  * Copyright (c) 1997
  *	Jason R. Thorpe.  All rights reserved
+ *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
  *    documentation and/or other materials provided with the distribution.
  * 3. All advertising materials mentioning features or use of this software
  *    must display the following acknowledgements:
  *	This product includes software developed for the NetBSD Project
  *	by Matthias Drochner.
  *	This product includes software developed for the NetBSD Project
  *	by Perry E. Metzger.
  * 4. The names of the authors may not be used to endorse or promote products
  *    derived from this software without specific prior written permission.
+ *
  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 /* Based on stand/biosboot/main.c */
 #include <sys/types.h>
 #include <sys/reboot.h>
 #include <sys/bootblock.h>
 #include <lib/libsa/stand.h>
 #include <lib/libsa/bootcfg.h>
 #include <lib/libsa/ufs.h>
 #include <lib/libkern/libkern.h>
 #include <libi386.h>
 #include <bootmod.h>
 #include <bootmenu.h>
 #include <biosdisk.h>
 #include <vbe.h>
 #include "devopen.h"
 #ifdef SUPPORT_PS2
 #include <biosmca.h>
 #endif
 extern struct x86_boot_params boot_params;
 extern	const char bootprog_name[], bootprog_rev[], bootprog_kernrev[];
 int errno;
 int boot_biosdev;
 daddr_t boot_biossector;
 static const char * const names[][2] = {
 	{ "netbsd", "netbsd.gz" },
 	{ "onetbsd", "onetbsd.gz" },
 	{ "netbsd.old", "netbsd.old.gz" },
 };
 #define NUMNAMES (sizeof(names)/sizeof(names[0]))
 #define DEFFILENAME names[0][0]
 #ifndef NO_GPT
 #define MAXDEVNAME 39 /* "NAME=" + 34 char part_name */
 #else
 #define MAXDEVNAME 16
 #endif
 static char *default_devname;
 static int default_unit, default_partition;
 static const char *default_filename;
 static const char *default_part_name;
 char *sprint_bootsel(const char *);
 static void bootit(const char *, int);
 void print_banner(void);
 void boot2(int, uint64_t);
 void	command_help(char *);
 #if LIBSA_ENABLE_LS_OP
 void	command_ls(char *);
 #endif
 void	command_quit(char *);
 void	command_boot(char *);
 void	command_dev(char *);
 void	command_consdev(char *);
 #ifndef SMALL
 void	command_menu(char *);
 #endif
 void	command_modules(char *);
 void	command_multiboot(char *);
 const struct bootblk_command commands[] = {
 	{ "help",	command_help },
 	{ "?",		command_help },
 #if LIBSA_ENABLE_LS_OP
 	{ "ls",		command_ls },
 #endif
 	{ "quit",	command_quit },
 	{ "boot",	command_boot },
 	{ "dev",	command_dev },
 	{ "consdev",	command_consdev },
 #ifndef SMALL
 	{ "menu",	command_menu },
 #endif
 	{ "modules",	command_modules },
 	{ "load",	module_add },
 	{ "multiboot",	command_multiboot },
 	{ "vesa",	command_vesa },
 	{ "splash",	splash_add },
 	{ "rndseed",	rnd_add },
 	{ "fs",		fs_add },
 	{ "userconf",	userconf_add },
 	{ NULL,		NULL },
 };
 int
 parsebootfile(const char *fname, char **fsname, char **devname,
 	      int *unit, int *partition, const char **file)
+{
 	const char *col;
 	static char savedevname[MAXDEVNAME+1];
 	*fsname = "ufs";
 	if (default_part_name == NULL) {
 		*devname = default_devname;
 	} else {
 		snprintf(savedevname, sizeof(savedevname),
 		    "NAME=%s", default_part_name);
 		*devname = savedevname;
+	}
 	*unit = default_unit;
 	*partition = default_partition;
 	*file = default_filename;
 	if (fname == NULL)
 		return 0;
 	if ((col = strchr(fname, ':')) != NULL) {	/* device given */
 		int devlen;
 		int u = 0, p = 0;
 		int i = 0;
 		devlen = col - fname;
 		if (devlen > MAXDEVNAME)
 			return EINVAL;
 #ifndef NO_GPT
 		if (strstr(fname, "NAME=") == fname) {
 			strlcpy(savedevname, fname, devlen + 1);
 			*devname = savedevname;
 			*unit = -1;
 			*partition = -1;
 			fname = col + 1;
 			goto out;
+		}
 #endif
 #define isvalidname(c) ((c) >= 'a' && (c) <= 'z')
 		if (!isvalidname(fname[i]))
 			return EINVAL;
 		do {
 			savedevname[i] = fname[i];
 			i++;
 		} while (isvalidname(fname[i]));
 		savedevname[i] = '\0';
 #define isnum(c) ((c) >= '0' && (c) <= '9')
 		if (i < devlen) {
 			if (!isnum(fname[i]))
 				return EUNIT;
 			do {
 				u *= 10;
 				u += fname[i++] - '0';
 			} while (isnum(fname[i]));
+		}
 #define isvalidpart(c) ((c) >= 'a' && (c) <= 'z')
 		if (i < devlen) {
 			if (!isvalidpart(fname[i]))
 				return EPART;
 			p = fname[i++] - 'a';
+		}
 		if (i != devlen)
 			return ENXIO;
 		*devname = savedevname;
 		*unit = u;
 		*partition = p;
 		fname = col + 1;
+	}
 out:
 	if (*fname)
 		*file = fname;
 	return 0;
+}
 char *
 sprint_bootsel(const char *filename)
+{
 	char *fsname, *devname;
 	int unit, partition;
 	const char *file;
 	static char buf[80];
 	if (parsebootfile(filename, &fsname, &devname, &unit,
 			  &partition, &file) == 0) {
 		if (strstr(devname, "NAME=") == devname)
 			snprintf(buf, sizeof(buf), "%s:%s", devname, file);
 		else
 			snprintf(buf, sizeof(buf), "%s%d%c:%s", devname, unit,
 			    'a' + partition, file);
 		return buf;
+	}
 	return "(invalid)";
+}
 static void
 clearit(void)
+{
 	if (bootcfg_info.clear)
 		clear_pc_screen();
+}
 static void
 bootit(const char *filename, int howto)
+{
 	if (howto & AB_VERBOSE)
 		printf("booting %s (howto 0x%x)\n", sprint_bootsel(filename),
 		    howto);
 	if (exec_netbsd(filename, 0, howto, boot_biosdev < 0x80, clearit) < 0)
 		printf("boot: %s: %s\n", sprint_bootsel(filename),
 		       strerror(errno));
 	else
 		printf("boot returned\n");
+}
 void
 print_banner(void)
+{
 	clearit();
 #ifndef SMALL
 	int n;
 	if (bootcfg_info.banner[0]) {
 		for (n = 0; n < BOOTCFG_MAXBANNER && bootcfg_info.banner[n];
 		    n++)
 			printf("%s\n", bootcfg_info.banner[n]);
 	} else {
 #endif /* !SMALL */
 		printf("\n"
 		       ">> %s, Revision %s (from NetBSD %s)\n"
 		       ">> Memory: %d/%d k\n",
 		       bootprog_name, bootprog_rev, bootprog_kernrev,
 		       getbasemem(), getextmem());
 #ifndef SMALL
+	}
 #endif /* !SMALL */
+}
 /*
  * Called from the initial entry point boot_start in biosboot.S
+ *
  * biosdev: BIOS drive number the system booted from
  * biossector: Sector number of the NetBSD partition
  */
 void
 boot2(int biosdev, uint64_t biossector)
+{
 	extern char twiddle_toggle;
 	int currname;
 	char c;
 	twiddle_toggle = 1;	/* no twiddling until we're ready */
 	initio(boot_params.bp_consdev);
 #ifdef SUPPORT_PS2
 	biosmca();
 #endif
 	gateA20();
 	boot_modules_enabled = !(boot_params.bp_flags
 				 & X86_BP_FLAGS_NOMODULES);
 	if (boot_params.bp_flags & X86_BP_FLAGS_RESET_VIDEO)
 		biosvideomode();
 	vbe_init();
 	/* need to remember these */
 	boot_biosdev = biosdev;
 	boot_biossector = biossector;
 	/* try to set default device to what BIOS tells us */
 	bios2dev(biosdev, biossector, &default_devname, &default_unit,
 		 &default_partition, &default_part_name);
 	/* if the user types "boot" without filename */
 	default_filename = DEFFILENAME;
 #ifndef SMALL
 	if (!(boot_params.bp_flags & X86_BP_FLAGS_NOBOOTCONF)) {
 		parsebootconf(BOOTCFG_FILENAME);
 	} else {
 		bootcfg_info.timeout = boot_params.bp_timeout;
+	}
 	/*
 	 * If console set in boot.cfg, switch to it.
 	 * This will print the banner, so we don't need to explicitly do it
 	 */
 	if (bootcfg_info.consdev)
 		command_consdev(bootcfg_info.consdev);
 	else
 		print_banner();
 	/* Display the menu, if applicable */
 	twiddle_toggle = 0;
 	if (bootcfg_info.nummenu > 0) {
 		/* Does not return */
 		doboottypemenu();
+	}
 #else
 	twiddle_toggle = 0;
 	print_banner();
 #endif
 	printf("Press return to boot now, any other key for boot menu\n");
 	for (currname = 0; currname < NUMNAMES; currname++) {
 		printf("booting %s - starting in ",
 		       sprint_bootsel(names[currname][0]));
 #ifdef SMALL
 		c = awaitkey(boot_params.bp_timeout, 1);
 #else
 		c = awaitkey((bootcfg_info.timeout < 0) ? 0
 		    : bootcfg_info.timeout, 1);
 #endif
 		if ((c != '\r') && (c != '\n') && (c != '\0')) {
 		    if ((boot_params.bp_flags & X86_BP_FLAGS_PASSWORD) == 0) {
 			/* do NOT ask for password */
 			bootmenu(); /* does not return */
 		    } else {
 			/* DO ask for password */
 			if (check_password((char *)boot_params.bp_password)) {
 			    /* password ok */
 			    printf("type \"?\" or \"help\" for help.\n");
 			    bootmenu(); /* does not return */
 			} else {
 			    /* bad password */
 			    printf("Wrong password.\n");
 			    currname = 0;
 			    continue;
+			}
+		    }
+		}
 		/*
 		 * try pairs of names[] entries, foo and foo.gz
 		 */
 		/* don't print "booting..." again */
 		bootit(names[currname][0], 0);
 		/* since it failed, try compressed bootfile. */
 		bootit(names[currname][1], AB_VERBOSE);
+	}
 	bootmenu();	/* does not return */
+}
 /* ARGSUSED */
 void
 command_help(char *arg)
+{
 	printf("commands are:\n"
 	       "boot [dev:][filename] [-12acdqsvxz]\n"
 #ifndef NO_RAIDFRAME
 	       "     dev syntax is (hd|fd|cd|raid)[N[x]]\n"
 #else
 	       "     dev syntax is (hd|fd|cd)[N[x]]n"
 #endif
 #ifndef NO_GPT
 	       "                or NAME=gpt_label\n"
 #endif
 	       "     (ex. \"hd0a:netbsd.old -s\")\n"
 #if LIBSA_ENABLE_LS_OP
 	       "ls [dev:][path]\n"
 #endif
 	       "dev [dev:]\n"
-	       "consdev {pc|com[0123]|com[0123]kbd|auto}\n"
+	       "consdev {pc|{com[0123]|com[0123]kbd|auto}[,{speed}]}\n"
 	       "vesa {modenum|on|off|enabled|disabled|list}\n"
 #ifndef SMALL
 	       "menu (reenters boot menu, if defined in boot.cfg)\n"
 #endif
 	       "modules {on|off|enabled|disabled}\n"
 	       "load {path_to_module}\n"
 	       "multiboot [dev:][filename] [<args>]\n"
 	       "splash {path_to_image_file}\n"
 	       "userconf {command}\n"
 	       "rndseed {path_to_rndseed_file}\n"
 	       "help|?\n"
 	       "quit\n");
+}
 #if LIBSA_ENABLE_LS_OP
 void
 command_ls(char *arg)
+{
 	const char *save = default_filename;
 	default_filename = "/";
 	ls(arg);
 	default_filename = save;
+}
 #endif
 /* ARGSUSED */
 void
 command_quit(char *arg)
+{
 	printf("Exiting...\n");
 	delay(1000000);
 	reboot();
 	/* Note: we shouldn't get to this point! */
 	panic("Could not reboot!");
+}
 void
 command_boot(char *arg)
+{
 	char *filename;
 	int howto;
 	if (!parseboot(arg, &filename, &howto))
 		return;
 	if (filename != NULL) {
 		bootit(filename, howto);
 	} else {
 		int i;
 #ifndef SMALL
 		if (howto == 0)
 			bootdefault();
 #endif
 		for (i = 0; i < NUMNAMES; i++) {
 			bootit(names[i][0], howto);
 			bootit(names[i][1], howto);
+		}
+	}
+}
 void
 command_dev(char *arg)
+{
 	static char savedevname[MAXDEVNAME + 1];
 	char *fsname, *devname;
 	const char *file; /* dummy */
 	if (*arg == '\0') {
 		biosdisk_probe();
 #ifndef NO_GPT
 		if (default_part_name)
 			printf("default NAME=%s on %s%d\n", default_part_name,
 			       default_devname, default_unit);
 		else
 #endif
 			printf("default %s%d%c\n",
 			       default_devname, default_unit,
 			       'a' + default_partition);
 		return;
+	}
 	if (strchr(arg, ':') == NULL ||
 	    parsebootfile(arg, &fsname, &devname, &default_unit,
 			  &default_partition, &file)) {
 		command_help(NULL);
 		return;
+	}
 	/* put to own static storage */
 	strncpy(savedevname, devname, MAXDEVNAME + 1);
 	default_devname = savedevname;
 	/* +5 to skip leading NAME= */
 	if (strstr(devname, "NAME=") == devname)
 		default_part_name = default_devname + 5;
+}
 static const struct cons_devs {
 	const char	*name;
 	u_int		tag;
 } cons_devs[] = {
 	{ "pc",		CONSDEV_PC },
 	{ "com0",	CONSDEV_COM0 },
 	{ "com1",	CONSDEV_COM1 },
 	{ "com2",	CONSDEV_COM2 },
 	{ "com3",	CONSDEV_COM3 },
 	{ "com0kbd",	CONSDEV_COM0KBD },
 	{ "com1kbd",	CONSDEV_COM1KBD },
 	{ "com2kbd",	CONSDEV_COM2KBD },
 	{ "com3kbd",	CONSDEV_COM3KBD },
 	{ "auto",	CONSDEV_AUTO },
 	{ NULL,		0 }
 };
 void
 command_consdev(char *arg)
+{
 	const struct cons_devs *cdp;
 	char *sep;
 	int speed;
 	sep = strchr(arg, ',');
 	if (sep != NULL)
 		*sep++ = '\0';
 	for (cdp = cons_devs; cdp->name; cdp++) {
-		if (strcmp(arg, cdp->name) == 0) {
+		if (strcmp(arg, cdp->name) != 0)
-			initio(cdp->tag);
+			continue;
 			print_banner();
-			return;
+		if (sep != NULL) {
 			if (cdp->tag == CONSDEV_PC)
 				goto error;
 			speed = atoi(sep);
 			if (speed < 0)
 				goto error;
 			boot_params.bp_conspeed = speed;
+		}
 		initio(cdp->tag);
 		print_banner();
 		return;
+	}
 error:
 	printf("invalid console device.\n");
+}
 #ifndef SMALL
 /* ARGSUSED */
 void
 command_menu(char *arg)
+{
 	if (bootcfg_info.nummenu > 0) {
 		/* Does not return */
 		doboottypemenu();
 	} else {
 		printf("No menu defined in boot.cfg\n");
+	}
+}
 #endif /* !SMALL */
 void
 command_modules(char *arg)
+{
 	if (strcmp(arg, "enabled") == 0 ||
 	    strcmp(arg, "on") == 0)
 		boot_modules_enabled = true;
 	else if (strcmp(arg, "disabled") == 0 ||
 	    strcmp(arg, "off") == 0)
 		boot_modules_enabled = false;
 	else
 		printf("invalid flag, must be 'enabled' or 'disabled'.\n");
+}
 void
 command_multiboot(char *arg)
+{
 	char *filename;
 	filename = arg;
 	if (exec_multiboot(filename, gettrailer(arg)) < 0)
 		printf("multiboot: %s: %s\n", sprint_bootsel(filename),
 		       strerror(errno));
 	else
 		printf("boot returned\n");
+}