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 X-Spam-Level: X-Spam-Status: No, score=-3.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1B58CC4338F for ; Wed, 25 Aug 2021 07:24:24 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id A85566127B for ; Wed, 25 Aug 2021 07:24:23 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org A85566127B Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=bugs.launchpad.net Authentication-Results: mail.kernel.org; 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Wed, 25 Aug 2021 07:20:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=launchpad.net; s=20210803; t=1629876044; bh=5J5Sgs9s1wUsUD0i1Pg9RMcEbAD+BQdXSqA7RTxof50=; h=MIME-Version:Content-Type:Date:From:To:Reply-To:References: Message-Id:Subject; b=iU13ZP7VLVu1g+T4Ix9tgKXOAw48bOLeS/e0agKYcLFfwgI71nDOFg/vSYqzt62bR ZXSn/bWjk6dNBOQswlmjaO70EtnA6Z6vIn2hFoU+5l7x/tKMRd+Uo7BloH0iMYFiD2 by5nQHrlZcyAV+j1nSHxHmQGj5avkqOJkNZhqqnOSL2/LCjbnsLl2LSdho+hzGpu6V o8tR/SAlUbJBvIbKH6CdUxvjhgHUBiPrV+Ski0PeGjhwH19gEpoToumF1QF+n1HncA zlbO75n0q6V6XmsP1yDbnCTVTbXafqpjV91mSpuHUf2fNiIJupsWLCbpLWAcimOK6K z9l1Jm1JPunmw== Received: from loganberry.canonical.com (localhost [127.0.0.1]) by loganberry.canonical.com (Postfix) with ESMTP id E624E2E816E for ; Wed, 25 Aug 2021 07:20:42 +0000 (UTC) MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Date: Wed, 25 Aug 2021 07:12:45 -0000 From: Thomas Huth <1922887@bugs.launchpad.net> To: qemu-devel@nongnu.org X-Launchpad-Notification-Type: bug X-Launchpad-Bug: product=qemu; status=Fix Released; importance=Undecided; assignee=None; X-Launchpad-Bug-Tags: arm X-Launchpad-Bug-Information-Type: Public X-Launchpad-Bug-Private: no X-Launchpad-Bug-Security-Vulnerability: no X-Launchpad-Bug-Commenters: muhui pmaydell th-huth X-Launchpad-Bug-Reporter: JIANG Muhui (muhui) X-Launchpad-Bug-Modifier: Thomas Huth (th-huth) References: <161778201158.26656.2798489764705445614.malonedeb@wampee.canonical.com> Message-Id: <162987556669.10640.6263984381539780893.launchpad@chaenomeles.canonical.com> Subject: [Bug 1922887] Re: STR in Thumb 32 decode problem X-Launchpad-Message-Rationale: Subscriber (QEMU) @qemu-devel-ml X-Launchpad-Message-For: qemu-devel-ml Precedence: bulk X-Generated-By: Launchpad (canonical.com); Revision="7edb2d45353e030166106ae05838b77ab406edcd"; Instance="production" X-Launchpad-Hash: b74c1a4696606743bd14b860bc1a9f2f0b4265b6 Received-SPF: pass client-ip=185.125.188.251; envelope-from=noreply@launchpad.net; helo=smtp-relay-services-1.canonical.com X-Spam_score_int: -42 X-Spam_score: -4.3 X-Spam_bar: ---- X-Spam_report: (-4.3 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_MED=-2.3, RCVD_IN_MSPIKE_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: Bug 1922887 <1922887@bugs.launchpad.net> Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" ** Changed in: qemu Status: Fix Committed =3D> Fix Released --=20 You received this bug notification because you are a member of qemu- devel-ml, which is subscribed to QEMU. https://bugs.launchpad.net/bugs/1922887 Title: STR in Thumb 32 decode problem Status in QEMU: Fix Released Bug description: Hi It seems that QEMU does not have a proper check on the STR instruction in Thumb32 mode. Specifically, the machine code is 0xf84f0ddd, which is 0b1111 1000 0100 1= 111 0000 1101 1101 1101.=20 This is an STR (immediate, Thumb) instruction with a T4 encoding scheme. The symbols is Rn =3D 1111 Rt =3D 0000 P =3D 1 U =3D 0 W =3D 1 The decode ASL is below: if P =3D=3D =E2=80=981=E2=80=99 && U =3D=3D =E2=80=981=E2=80=99 && W =3D= =3D =E2=80=980=E2=80=99 then SEE STRT; if Rn =3D=3D =E2=80=981101=E2=80=99 && P =3D=3D =E2=80=981=E2=80=99 && U = =3D=3D =E2=80=980=E2=80=99 && W =3D=3D =E2=80=981=E2=80=99 && imm8 =3D=3D = =E2=80=9800000100=E2=80=99 then SEE PUSH; if Rn =3D=3D =E2=80=981111=E2=80=99 || (P =3D=3D =E2=80=980=E2=80=99 && W= =3D=3D =E2=80=980=E2=80=99) then UNDEFINED; t =3D UInt(Rt); n =3D UInt(Rn); imm32 =3D ZeroExtend(imm8, 32); index =3D (P =3D=3D =E2=80=981=E2=80=99); add =3D (U =3D=3D =E2=80=981=E2= =80=99); wback =3D (W =3D=3D =E2=80=981=E2=80=99); if t =3D=3D 15 || (wback && n =3D=3D t) then UNPREDICTABLE; When Rn =3D=3D 1111, it should be an undefined instruction, which should raise SEGILL signal. However, it seems that QEMU does not check this constraint, which should be a bug. Many thanks Regards Muhui To manage notifications about this bug go to: https://bugs.launchpad.net/qemu/+bug/1922887/+subscriptions