From nobody Tue Nov 15 17:52:24 2022 X-Original-To: freebsd-arch@mlmmj.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mlmmj.nyi.freebsd.org (Postfix) with ESMTP id 4NBYfp2Z98z4hLtN for ; Tue, 15 Nov 2022 17:52:34 +0000 (UTC) (envelope-from sgk@troutmask.apl.washington.edu) Received: from troutmask.apl.washington.edu (troutmask.apl.washington.edu [128.95.76.21]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256 client-signature RSA-PSS (2048 bits) client-digest SHA256) (Client CN "troutmask", Issuer "troutmask" (not verified)) by mx1.freebsd.org (Postfix) with ESMTPS id 4NBYfn6XM6z45Bd for ; Tue, 15 Nov 2022 17:52:33 +0000 (UTC) (envelope-from sgk@troutmask.apl.washington.edu) Authentication-Results: mx1.freebsd.org; none Received: from troutmask.apl.washington.edu (localhost [127.0.0.1]) by troutmask.apl.washington.edu (8.16.1/8.16.1) with ESMTPS id 2AFHqOvI066850 (version=TLSv1.3 cipher=TLS_AES_256_GCM_SHA384 bits=256 verify=NO); Tue, 15 Nov 2022 09:52:24 -0800 (PST) (envelope-from sgk@troutmask.apl.washington.edu) Received: (from sgk@localhost) by troutmask.apl.washington.edu (8.16.1/8.16.1/Submit) id 2AFHqOiS066849; Tue, 15 Nov 2022 09:52:24 -0800 (PST) (envelope-from sgk) Date: Tue, 15 Nov 2022 09:52:24 -0800 From: Steve Kargl To: Warner Losh Cc: "freebsd-arch@freebsd.org" Subject: Re: Giant Locked drivers Message-ID: Reply-To: sgk@troutmask.apl.washington.edu References: List-Id: Discussion related to FreeBSD architecture List-Archive: https://lists.freebsd.org/archives/freebsd-arch List-Help: List-Post: List-Subscribe: List-Unsubscribe: Sender: owner-freebsd-arch@freebsd.org MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Rspamd-Queue-Id: 4NBYfn6XM6z45Bd X-Spamd-Bar: ---- X-Spamd-Result: default: False [-4.00 / 15.00]; REPLY(-4.00)[]; ASN(0.00)[asn:73, ipnet:128.95.0.0/16, country:US] X-Rspamd-Pre-Result: action=no action; module=replies; Message is reply to one we originated X-ThisMailContainsUnwantedMimeParts: N On Tue, Nov 15, 2022 at 10:37:36AM -0700, Warner Losh wrote: > > It's no secret fiant-locked drivers' days are numbered. We've been more > sluggish about eliminating Giant than had been hoped. I plan in the coming > weeks to add a tunable 'debug.giant_drivers' which initially will be set to > enable/disable giant-locked drivers in the tree. > > When set to 0, you get today's behavior. If set to 1, it will no longer > allow drivers that don't request MPSAFE interrupt handlers from registering > (the interrupt setup will return an error). > > This will allow us to understand what is lost if we throw the switch, and > allow users to proactively test their systems to see if they are > affected or not (and if they are, if they want to live without the > functionality, or want to fund work in the area). > > Comments? > Is there a list of effected drivers? Grepping /var/run/dmesg.boot on my system shows only "atkbd0: [GIANT-LOCKED]". A scan of atkbd(4) shows This driver is required for the console driver syscons(4) or vt(4). So, setting debug.giant_drivers=1 will brick all FreeBSD workstations? -- Steve