From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:46208) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XwctT-0003XM-5f for qemu-devel@nongnu.org; Thu, 04 Dec 2014 15:21:01 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1XwctM-0001Yq-Ux for qemu-devel@nongnu.org; Thu, 04 Dec 2014 15:20:55 -0500 Received: from indium.canonical.com ([91.189.90.7]:49754) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XwctL-0001Yb-Us for qemu-devel@nongnu.org; Thu, 04 Dec 2014 15:20:48 -0500 Received: from loganberry.canonical.com ([91.189.90.37]) by indium.canonical.com with esmtp (Exim 4.76 #1 (Debian)) id 1XwctK-0007wr-Uq for ; Thu, 04 Dec 2014 20:20:46 +0000 Received: from loganberry.canonical.com (localhost [127.0.0.1]) by loganberry.canonical.com (Postfix) with ESMTP id E662A2E80C1 for ; Thu, 4 Dec 2014 20:20:46 +0000 (UTC) MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Date: Thu, 04 Dec 2014 20:11:04 -0000 From: Chris J Arges <1349277@bugs.launchpad.net> Sender: bounces@canonical.com References: <20140728074056.4555.84832.malonedeb@gac.canonical.com> Message-Id: <20141204201105.27016.74327.launchpad@wampee.canonical.com> Errors-To: bounces@canonical.com Subject: [Qemu-devel] [Bug 1349277] Re: AArch64 emulation ignores SPSel=0 when taking (or returning from) an exception at EL1 or greater Reply-To: Bug 1349277 <1349277@bugs.launchpad.net> List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org ** Changed in: qemu (Ubuntu) Assignee: (unassigned) =3D> Chris J Arges (arges) ** Changed in: qemu (Ubuntu) Status: New =3D> In Progress ** Changed in: qemu (Ubuntu) Importance: Undecided =3D> Medium -- = You received this bug notification because you are a member of qemu- devel-ml, which is subscribed to QEMU. https://bugs.launchpad.net/bugs/1349277 Title: AArch64 emulation ignores SPSel=3D0 when taking (or returning from) an exception at EL1 or greater Status in QEMU: New Status in qemu package in Ubuntu: In Progress Bug description: The AArch64 emulation ignores SPSel=3D0 when: (1) taking an interrupt from an exception level greater than EL0 (e.g., EL1t), (2) returning from an exception (via ERET) to an exception level greater than EL0 (e.g., EL1t), with SPSR_ELx[SPSel]=3D0. The attached patch fixes the problem in my application. Background: I'm running a standalone application (toy OS) that is performing preemptive multithreading between threads running at EL1t, with exception handling / context switching occurring at EL1h. This bug causes the stack pointer to be corrupted in the threads running at EL1t (they end up with a version of the EL1h stack pointer (SP_EL1)). Occurs in: qemu-2.1.0-rc1 (found in) commit c60a57ff497667780132a3fcdc1500c83af5d5c0 (current master) To manage notifications about this bug go to: https://bugs.launchpad.net/qemu/+bug/1349277/+subscriptions