From nobody Mon Feb 9 11:51:20 2026 Delivered-To: importer@patchew.org Received-SPF: pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) client-ip=208.118.235.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Authentication-Results: mx.zoho.com; spf=pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; Return-Path: Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) by mx.zohomail.com with SMTPS id 1491845765440742.9311429897039; Mon, 10 Apr 2017 10:36:05 -0700 (PDT) Received: from localhost ([::1]:35649 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1cxdES-00024H-BA for importer@patchew.org; Mon, 10 Apr 2017 13:36:04 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:60836) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1cxdCf-0000n4-2t for qemu-devel@nongnu.org; Mon, 10 Apr 2017 13:34:14 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1cxdCc-0006ry-PU for qemu-devel@nongnu.org; Mon, 10 Apr 2017 13:34:11 -0400 Received: from orth.archaic.org.uk ([2001:8b0:1d0::2]:49130) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1cxdCa-0006qG-O3; Mon, 10 Apr 2017 13:34:08 -0400 Received: from pm215 by orth.archaic.org.uk with local (Exim 4.84_2) (envelope-from ) id 1cxcsn-0005hv-P3; Mon, 10 Apr 2017 18:13:41 +0100 From: Peter Maydell To: qemu-arm@nongnu.org, qemu-devel@nongnu.org Date: Mon, 10 Apr 2017 18:13:32 +0100 Message-Id: <1491844419-12485-3-git-send-email-peter.maydell@linaro.org> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1491844419-12485-1-git-send-email-peter.maydell@linaro.org> References: <1491844419-12485-1-git-send-email-peter.maydell@linaro.org> X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 2001:8b0:1d0::2 Subject: [Qemu-devel] [PATCH v2 2/9] arm: Thumb shift operations should not permit interworking branches X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Richard Henderson , =?UTF-8?q?Philippe=20Mathieu-Daud=C3=A9?= , patches@linaro.org Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail: RSF_0 Z_629925259 SPT_0 Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" In Thumb mode, the only instructions which can cause an interworking branch by writing the PC are BLX, BX, BXJ, LDR, POP and LDM. Unlike ARM mode, data processing instructions which target the PC do not cause interworking branches. When we added support for doing interworking branches on writes to PC from data processing instructions in commit 21aeb3430ce7ba, we accidentally changed a Thumb instruction to have interworking branch behaviour for writes to PC. (MOV, MOVS register-shifted register, encoding T2; this is the standard encoding for LSL/LSR/ASR/ROR (register).) For this encoding, behaviour with Rd =3D=3D R15 is specified as UNPREDICTABLE, so allowing an interworking branch is within spec, but it's confusing and differs from our handling of this class of UNPREDICTABLE for other Thumb ALU operations. Make it perform a simple (non-interworking) branch like the others. Signed-off-by: Peter Maydell --- target/arm/translate.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/target/arm/translate.c b/target/arm/translate.c index fe3f442..ddc62b6 100644 --- a/target/arm/translate.c +++ b/target/arm/translate.c @@ -9959,7 +9959,7 @@ static int disas_thumb2_insn(CPUARMState *env, DisasC= ontext *s, uint16_t insn_hw gen_arm_shift_reg(tmp, op, tmp2, logic_cc); if (logic_cc) gen_logic_CC(tmp); - store_reg_bx(s, rd, tmp); + store_reg(s, rd, tmp); break; case 1: /* Sign/zero extend. */ op =3D (insn >> 20) & 7; --=20 2.7.4