NetBSD Problem Report #52414

From paul@whooppee.com  Mon Jul 17 11:07:03 2017
Return-Path: <paul@whooppee.com>
Received: from mail.netbsd.org (mail.netbsd.org [199.233.217.200])
	(using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits))
	(Client CN "mail.netbsd.org", Issuer "Postmaster NetBSD.org" (not verified))
	by mollari.NetBSD.org (Postfix) with ESMTPS id 980C47A174
	for <gnats-bugs@gnats.NetBSD.org>; Mon, 17 Jul 2017 11:07:03 +0000 (UTC)
Message-Id: <20170717110700.3C68E16E6C@speedy.whooppee.com>
Date: Mon, 17 Jul 2017 19:07:00 +0800 (+08)
From: paul@whooppee.com
Reply-To: paul@whooppee.com
To: gnats-bugs@NetBSD.org
Subject: cpuctl(8)/cpuctl(4) shortcomings
X-Send-Pr-Version: 3.95

>Number:         52414
>Category:       bin
>Synopsis:       cpuctl(8)/cpuctl(4) shortcomings
>Confidential:   no
>Severity:       non-critical
>Priority:       medium
>Responsible:    bin-bug-people
>State:          open
>Class:          doc-bug
>Submitter-Id:   net
>Arrival-Date:   Mon Jul 17 11:10:00 +0000 2017
>Originator:     Paul Goyette
>Release:        NetBSD 8.99.1
>Organization:
+------------------+--------------------------+----------------------------+
| Paul Goyette     | PGP Key fingerprint:     | E-mail addresses:          |
| (Retired)        | FA29 0E3B 35AF E8AE 6651 | paul at whooppee dot com   |
| Kernel Developer | 0786 F758 55DE 53BA 7731 | pgoyette at netbsd dot org |
+------------------+--------------------------+----------------------------+
>Environment:


System: NetBSD speedy.whooppee.com 8.99.1 NetBSD 8.99.1 (SPEEDY 2017-06-28 12:54:24 UTC) #0: Wed Jun 28 17:26:09 UTC 2017 paul@speedy.whooppee.com:/build/netbsd-local/obj/amd64/sys/arch/amd64/compile/SPEEDY amd64
Architecture: x86_64
Machine: amd64
>Description:
(I've marked this as a doc-bug even though there are suggestions for
improving the code itself.  Please feel free to recategorize if needed.

Current the cpuctl(8) man-page is very amd centric for the microcode update
function.  It specifies an amd-specific default filename and the FILES
section lists only the /libdata/firmware/x86/amd/ directory.  It also
provides a download URL for the microcode files only for amd!

It might also be nice for the code to be changed to detect Intel-vs-AMD
characteristic and apply different defaults.  (For Intel, the default
file could be /libdata/firmware/x86/intel/FF-MM-SS since the Intel files
as currently distributed are named for the CPU's Family-Model-Stepping.)

It certainly doesn't make sense to have an amd-specific default filename
for non-amd processors.  Preferably the code will validate that the file
used is appropriate for the processor in question.  Which brings up yet
another shortcoming of the current man-page and/or code:  are there any
reasonable DIAGNOSTICS issued if the microcode file is not appropriate
for the processor being updated?  And/or is there any iBUG/CAVEAT needed
to warn users that applying an incorrect microcode file might render the
processor unuseable?

Finally, the cpuctl(8) utility apparently uses a pseudo-device cpuctl(4).
Yet there is no man-page for cpuctl(4), so there exists no documentation
on the mechanism for retrieving or updating the information.  Since the
cpuctl(4) pseudo-device is included in all kernels by default, it only
seems reasonable to document the device interface.


>How-To-Repeat:

>Fix:


>Unformatted:

NetBSD Home
NetBSD PR Database Search

(Contact us) $NetBSD: query-full-pr,v 1.39 2013/11/01 18:47:49 spz Exp $
$NetBSD: gnats_config.sh,v 1.8 2006/05/07 09:23:38 tsutsui Exp $
Copyright © 1994-2014 The NetBSD Foundation, Inc. ALL RIGHTS RESERVED.