From patchwork Tue Aug 31 16:39:49 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Luis Fernando Fujita Pires X-Patchwork-Id: 1522701 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=nongnu.org (client-ip=209.51.188.17; helo=lists.gnu.org; envelope-from=qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org; receiver=) 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 ozlabs.org (Postfix) with ESMTPS id 4GzY2g0ZjXz9sW4 for ; Wed, 1 Sep 2021 02:45:15 +1000 (AEST) Received: from localhost ([::1]:38682 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1mL6sq-0006ls-Lf for incoming@patchwork.ozlabs.org; Tue, 31 Aug 2021 12:45:12 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:46834) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mL6ro-0006kJ-96; Tue, 31 Aug 2021 12:44:08 -0400 Received: from [201.28.113.2] (port=43158 helo=outlook.eldorado.org.br) by eggs.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1mL6rm-0008P9-TS; Tue, 31 Aug 2021 12:44:08 -0400 Received: from power9a ([10.10.71.235]) by outlook.eldorado.org.br with Microsoft SMTPSVC(8.5.9600.16384); Tue, 31 Aug 2021 13:42:55 -0300 Received: from eldorado.org.br (unknown [10.10.70.45]) by power9a (Postfix) with ESMTP id E93D0800930; Tue, 31 Aug 2021 13:42:53 -0300 (-03) From: Luis Pires To: qemu-devel@nongnu.org, qemu-ppc@nongnu.org Subject: [PATCH v2 01/19] host-utils: Fix overflow detection in divu128() Date: Tue, 31 Aug 2021 13:39:49 -0300 Message-Id: <20210831164007.297781-2-luis.pires@eldorado.org.br> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20210831164007.297781-1-luis.pires@eldorado.org.br> References: <20210831164007.297781-1-luis.pires@eldorado.org.br> MIME-Version: 1.0 X-OriginalArrivalTime: 31 Aug 2021 16:42:55.0767 (UTC) FILETIME=[3FBA5A70:01D79E87] X-Host-Lookup-Failed: Reverse DNS lookup failed for 201.28.113.2 (failed) Received-SPF: pass client-ip=201.28.113.2; envelope-from=luis.pires@eldorado.org.br; helo=outlook.eldorado.org.br X-Spam_score_int: -10 X-Spam_score: -1.1 X-Spam_bar: - X-Spam_report: (-1.1 / 5.0 requ) BAYES_00=-1.9, PDS_HP_HELO_NORDNS=0.001, RDNS_NONE=0.793, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=no autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Luis Pires , richard.henderson@linaro.org, groug@kaod.org, david@gibson.dropbear.id.au Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: "Qemu-devel" The previous code didn't detect overflows if the high 64-bit of the dividend were equal to the 64-bit divisor. In that case, 64 bits wouldn't be enough to hold the quotient. Signed-off-by: Luis Pires Reviewed-by: Richard Henderson --- util/host-utils.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/util/host-utils.c b/util/host-utils.c index 7b9322071d..a789a11b46 100644 --- a/util/host-utils.c +++ b/util/host-utils.c @@ -102,7 +102,7 @@ int divu128(uint64_t *plow, uint64_t *phigh, uint64_t divisor) *plow = dlo / divisor; *phigh = dlo % divisor; return 0; - } else if (dhi > divisor) { + } else if (dhi >= divisor) { return 1; } else {