From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 90743C43458 for ; Mon, 6 Jul 2026 14:41:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Type:MIME-Version: References:In-Reply-To:Subject:Cc:To:From:Message-ID:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=6LQ/y2h2nRLqXndWDULBhi5T2/R+6kxG1jgo+nng0ys=; b=Owa1gP2VETjAobSbkykci6xyBi ep+/61ec3I9aUitxq2kcFqEJzr2JVzFb6OZo1QIduT4loWbWCrYHgashZCtStcGjmvp6X/XDuZhxJ M/LpUrNJLrtVOpD2zjNyUBjnXg+LzzXHKr++GmRQXZYnTTU1evBrAOQ0lBAE158xT4L5adVvtS7lS bx8HzCxCnXgd4eNDNdRKWgFfMwqS5uaLlHXoi/eiTwZCykOahY8xKucK0gGafmSsLqDRkDFlztBnB GC7utx3T402HtJPukaXf4oVuETyrpfiw/foitgmWeyopzK9M1zyzp9EBJZQpEu6/YWrh8yiIj4kGl O/U8JcwA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1wgkVC-0000000CmS5-1oqc; Mon, 06 Jul 2026 14:40:54 +0000 Received: from tor.source.kernel.org ([172.105.4.254]) by bombadil.infradead.org with esmtps (Exim 4.99.1 #2 (Red Hat Linux)) id 1wgkVB-0000000CmRR-08Tb; Mon, 06 Jul 2026 14:40:53 +0000 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by tor.source.kernel.org (Postfix) with ESMTP id 789C8600FC; Mon, 6 Jul 2026 14:40:52 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 290791F000E9; Mon, 6 Jul 2026 14:40:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1783348852; bh=6LQ/y2h2nRLqXndWDULBhi5T2/R+6kxG1jgo+nng0ys=; h=Date:From:To:Cc:Subject:In-Reply-To:References; b=kUztyQznOqnePq7LBXwgCSWm5zm9g6MDIagM+6IdV1x6BK9DBKuhX0LrKVsSrEGam WYvaHbd0Q4Wpeg3JrtnM+M8416mwrwRC1pZ5Jypy04pLUhZqyGBHbKpDDi3L7aaW6T Yhz+IpKrpCzn27tyC4EK9QFUhPVYa1kdak1B9nl/rwvxCEreddXw8g6QHjBIuM2S6K 4ayXYcO/J9hPIuwA6EhoczTMbUJEq8Ben4k/3xeZNXVnGnypNct+xXFHeaKTrhOK9C 9Px7McL3QjUBdcuNaHBYiNKnjkEBjjn8rD6RPzwXo71k8jmvLtkpYeIAzvRQtah4kW vkaaaxep/aSsA== Received: from sofa.misterjones.org ([185.219.108.64] helo=goblin-girl.misterjones.org) by disco-boy.misterjones.org with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.98.2) (envelope-from ) id 1wgkV7-00000001zbL-3IFG; Mon, 06 Jul 2026 14:40:49 +0000 Date: Mon, 06 Jul 2026 15:40:49 +0100 Message-ID: <86h5mcp4em.wl-maz@kernel.org> From: Marc Zyngier To: John Cc: Mark Rutland , Daniel Lezcano , Thomas Gleixner , Rob Herring , Krzysztof Kozlowski , Conor Dooley , Florian Fainelli , Broadcom internal kernel review list , "Ivan T. Ivanov" , Stefan Wahren , Andrea della Porta , Peter Robinson , Stanimir Varbanov , =?UTF-8?B?TWHDrXJh?= Canal , Gregor Herburger , "linux-arm-kernel@lists.infradead.org" , "linux-kernel@vger.kernel.org" , "devicetree@vger.kernel.org" , "linux-rpi-kernel@lists.infradead.org" Subject: Re: [REGRESSION] Raspberry Pi 5 (BCM2712) hangs at boot since d87773de9efe (arm_arch_timer: default to EL2 virtual timer under VHE) In-Reply-To: References: User-Agent: Wanderlust/2.15.9 (Almost Unreal) SEMI-EPG/1.14.7 (Harue) FLIM-LB/1.14.9 (=?UTF-8?B?R29qxY0=?=) APEL-LB/10.8 EasyPG/1.0.0 Emacs/30.1 (aarch64-unknown-linux-gnu) MULE/6.0 (HANACHIRUSATO) MIME-Version: 1.0 (generated by SEMI-EPG 1.14.7 - "Harue") Content-Type: text/plain; charset=US-ASCII X-SA-Exim-Connect-IP: 185.219.108.64 X-SA-Exim-Rcpt-To: therealgraysky@proton.me, mark.rutland@arm.com, daniel.lezcano@kernel.org, tglx@kernel.org, robh@kernel.org, krzk+dt@kernel.org, conor+dt@kernel.org, florian.fainelli@broadcom.com, bcm-kernel-feedback-list@broadcom.com, iivanov@suse.de, wahrenst@gmx.net, andrea.porta@suse.com, pbrobinson@gmail.com, svarbanov@suse.de, mcanal@igalia.com, gregor.herburger@linutronix.de, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, devicetree@vger.kernel.org, linux-rpi-kernel@lists.infradead.org X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Mon, 06 Jul 2026 15:13:27 +0100, John wrote: > > Since commit d87773de9efe ("clocksource/drivers/arm_arch_timer: Default to EL2 virtual timer when running VHE"), the Raspberry Pi 5 (BCM2712, arm64) hangs during boot on v7.2-rc1 and later. Reverting that commit on top of v7.2-rc2 boots reliably. Found by bisection. > > Environment: - Raspberry Pi 5 Model B, arm64, device-tree boot (no ACPI) - CPUs start at EL2 with VHE - Mainline v7.2-rc1 and v7.2-rc2 > > Symptom: - Silent hang early in driver probe; no panic or oops. Boot banner shows > "arch_timer: cp15 timer running at 54.00MHz (hyp-virt)". The first blocking, timer-backed wait during probe never returns because the EL2 virtual timer's interrupt is not delivered on this SoC, so clockevents are dead. The softlockup/hung-task detectors can't fire either, since they depend on the same dead timer. > Is that a guess? Or do you know something we don't? Or worse, is this report entirely AI generated? > Cause: - BCM2712's timer node lists five interrupts including the EL2 virtual > timer (GIC PPI 12). The new default trusts that entry and switches to the EL2 virtual timer, whose interrupt is non-functional on this board. Before the commit, VHE systems used the EL2 physical timer, which works. > Again, how do you know it isn't functional? Could it be, for example, that the firmware has not configured the interrupt correctly? > Possible fix / workaround: - Removing the EL2 virtual-timer interrupt (GIC PPI 12) from the BCM2712 > timer node makes the driver fall back to the EL2 physical timer (the pre-commit behavior) and boots. Whether the correct fix is in the DT or in hardening the driver's PPI selection, I'll leave to you. > > #regzbot introduced: d87773de9efe1df6fe2ba379926f9df92f1a5913 A proposed fix has been posted at [1]. Until we hear from the implementer about the state of the HW, it is difficult to do anything. M. [1] https://lore.kernel.org/all/878q898ulx.wl-maz@kernel.org/ -- Without deviation from the norm, progress is not possible.