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Mention the new bootspec variable.

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Give more details about the root device configuration.
This commit is contained in:
mlelstv 2014-11-26 20:42:29 +00:00
parent fa438ee608
commit 7e594f6343
1 changed files with 66 additions and 13 deletions
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79
share/man/man9/cpu_rootconf.9
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@ -1,4 +1,4 @@
.\" $NetBSD: cpu_rootconf.9,v 1.8 2012/07/29 18:51:48 wiz Exp $
.\" $NetBSD: cpu_rootconf.9,v 1.9 2014/11/26 20:42:29 mlelstv Exp $
.\"
.\" Copyright (c) 2002 The NetBSD Foundation, Inc.
.\" All rights reserved.
@ -55,28 +55,81 @@ provides the global variables
.Fa booted_device ,
.Fa booted_partition ,
.Fa booted_startblk ,
.Fa booted_nblks ,
and
.Fa booted_nblks
and invokes the machine-independent function
.Fa bootspec .
.Fa cpu_rootconf
invokes the machine-independent function
.Fa rootconf
which
.Fa rootconf
then calls the function
which calls the function
.Fa setroot
to record the boot/root device and the boot partition information
to record the root device and the root partition information
for use in machine-independent code.
.Pp
For disk boot, if
.Fa booted_nblks
is not 0, then
.Fa rootconf
may adjust the global variables and determines the parameters
for setroot. This is for example used to translate a device
and partition number provided by the bootloader into a disk
wedge device covering the same partition.
.Pp
If the bootloader already identified a disk wedge, it passes
a non-zero value for
.Fa booted_nblks ,
then
.Fa booted_startblk
and
.Fa booted_nblks
are supposed to specify a disk wedge that is used as the root device.
Otherwise the
.Fa booted_partition
specify a disk wedge as the boot device.
.Pp
.Fa setroot
evaluates several sources to identify the root device in the
following order until a valid device is selected:
.Bl -enum
.It
The kernel configuration variable
.Fa rootspec
which is set by
.Xr config 1 .
The value is the name and unit of the root device, e.g. "sd0" (disk)
or "dk0" (wedge) or "le0" (network) or the prefix "wedge:" followed
by the name of the disk wedge. For disk devices the partition
passed as argument to
.Fa setroot
is used.
.It
The variable
.Fa bootspec
following the same syntax.
.It
The result of an interactive query of the root device if
.Fa boothowto
has set the flag RB_ASKNAME. The input uses the same syntax
as the previous sources. Here also the kernel dump device
is queried.
.It
The boot device and partition passed as arguments.
.El
.Pp
If a root device cannot be selected,
.Fa setroot
sets the RB_ASKNAME flag and loops.
.Pp
Otherwise the kernel dump device is identified in a similar
manner from
.Bl -enum
.It
The result of a previous interactive query. See above.
.It
The kernel configuration variable
.Fa dumpspec ,
if set.
.It
The second partition of the root device, if it is a regular disk.
.It
The first disk wedge device of type DKW_PTYPE_SWAP.
.El
.Sh SEE ALSO
.Xr dk 4 ,
.Xr boot 8 ,
.Xr config 1 ,
.Xr boothowto 9