Default to softraid on boot-device iff found

root on softraid on sparc64 currently requires explicitly passing the volume
name as part of the boot arguments, e.g.
	boot-file=sr0
	boot-file=sr0a:/bsd
or
	{ok} boot my-devalias sr0:

(ofwboot always probes for softraid devices, assembles them but continues
 to ignore such volumes unless specified.)

This is inconsistent with softraid support on other platforms and has
further drawbacks when it comes to sysupgrade logic.

Unless an explicit root disk was given, make ofwboot default to the softraid
volume on the boot device to make root on softraid work out of the box
without having to set variables or pass arguments in OpenBoot.

Eventually, ofwboot's disk discovery and softraid assembly machinery will be
fixed and boot-file won't be misused for softraid purposes anymore.

Remove the quirky softraid paragraph from boot_sparc64(8) now that it
is purely optional, expecting users from now on to either leave boot-file
empty or pass a kernel filename alone.

Tested on T4-2 guest domains with and without root on softraid.

Feedback claudio kettenis stsp
OK kettenis (previous diff)
OK stsp

1 files changed, 3 insertions, 20 deletions

diff --git a/share/man/man8/man8.sparc64/boot_sparc64.8 b/share/man/man8/man8.sparc64/boot_sparc64.8
index 9705046704a..90d9339f93c 100644
--- a/share/man/man8/man8.sparc64/boot_sparc64.8
+++ b/share/man/man8/man8.sparc64/boot_sparc64.8
@@ -1,4 +1,4 @@
-.\"	$OpenBSD: boot_sparc64.8,v 1.16 2015/10/03 13:22:06 stsp Exp $
+.\"	$OpenBSD: boot_sparc64.8,v 1.17 2022/08/04 09:16:53 kn Exp $
 .\"
 .\" Copyright (c) 1992, 1993
 .\"	The Regents of the University of California.  All rights reserved.
@@ -29,7 +29,7 @@
 .\"
 .\"     @(#)boot_sparc.8	8.2 (Berkeley) 4/19/94
 .\"
-.Dd $Mdocdate: October 3 2015 $
+.Dd $Mdocdate: August 4 2022 $
 .Dt BOOT_SPARC64 8 sparc64
 .Os
 .Sh NAME
@@ -90,29 +90,12 @@ bootloader will then look for a kernel named
 .Pa bsd
 by default, unless the
 .Va boot-file
-variable is set, or a different filename has been specified
+variable contains a filename, or a different filename has been specified
 in the boot command.
 To reset this variable to its default, empty, value, type the following:
 .Pp
 .D1 Sy ok Li set-default boot-file
 .Pp
-To boot from a
-.Xr softraid 4
-volume by default,
-.Va boot-device
-must be set to a disk device hosting a chunk of the softraid volume:
-.Pp
-.D1 Sy ok Li setenv boot-device disk0
-.Pp
-and
-.Va boot-file
-must contain the
-.Pq Pa sr
-device name of the softraid volume and optionally a partition letter
-and/or kernel:
-.Pp
-.D1 Sy ok Li setenv boot-file sr0a:/bsd
-.Pp
 Autoboot is enabled by setting the
 .Va auto-boot?\&
 variable to