From patchwork Wed Feb 5 19:58:25 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Marc Zyngier X-Patchwork-Id: 317269 Return-Path: X-Original-To: incoming-imx@patchwork.ozlabs.org Delivered-To: patchwork-incoming-imx@bilbo.ozlabs.org Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:770:15f::2]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 18E812C0084 for ; Thu, 6 Feb 2014 07:02:38 +1100 (EST) Received: from merlin.infradead.org ([2001:4978:20e::2]) by casper.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1WB8e8-0007Vl-Nk; Wed, 05 Feb 2014 20:00:37 +0000 Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1WB8cU-0007xZ-Tn; Wed, 05 Feb 2014 19:58:50 +0000 Received: from fw-tnat.austin.arm.com ([217.140.110.23] helo=collaborate-mta1.arm.com) by merlin.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1WB8cR-0007uQ-Kj for linux-arm-kernel@lists.infradead.org; Wed, 05 Feb 2014 19:58:48 +0000 Received: from e102391-lin.cambridge.arm.com (e102391-lin.cambridge.arm.com [10.1.209.166]) by collaborate-mta1.arm.com (Postfix) with ESMTP id E7EDF13F61D; Wed, 5 Feb 2014 13:58:25 -0600 (CST) From: Marc Zyngier To: linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org Subject: [PATCH] ARM: KVM: fix warning in mmu.c Date: Wed, 5 Feb 2014 19:58:25 +0000 Message-Id: <1391630305-8056-1-git-send-email-marc.zyngier@arm.com> X-Mailer: git-send-email 1.8.3.4 MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20140205_145847_752606_A9859C1B X-CRM114-Status: GOOD ( 11.21 ) X-Spam-Score: -2.4 (--) X-Spam-Report: SpamAssassin version 3.3.2 on merlin.infradead.org summary: Content analysis details: (-2.4 points) pts rule name description ---- ---------------------- -------------------------------------------------- -0.0 SPF_PASS SPF: sender matches SPF record -0.5 RP_MATCHES_RCVD Envelope sender domain matches handover relay domain -1.9 BAYES_00 BODY: Bayes spam probability is 0 to 1% [score: 0.0000] Cc: Christoffer Dall X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.15 Precedence: list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+incoming-imx=patchwork.ozlabs.org@lists.infradead.org List-Id: linux-imx-kernel.lists.patchwork.ozlabs.org Compiling with THP enabled leads to the following warning: arch/arm/kvm/mmu.c: In function ‘unmap_range’: arch/arm/kvm/mmu.c:177:39: warning: ‘pte’ may be used uninitialized in this function [-Wmaybe-uninitialized] if (kvm_pmd_huge(*pmd) || page_empty(pte)) { ^ Code inspection reveals that these two cases are mutually exclusive, so GCC is a bit overzealous here. But silence it anyway by setting pte to NULL if kvm_pmd_huge(*pmd) is true. Signed-off-by: Marc Zyngier --- arch/arm/kvm/mmu.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/arch/arm/kvm/mmu.c b/arch/arm/kvm/mmu.c index ea21b6a..3020221 100644 --- a/arch/arm/kvm/mmu.c +++ b/arch/arm/kvm/mmu.c @@ -169,12 +169,14 @@ static void unmap_range(struct kvm *kvm, pgd_t *pgdp, pte = pte_offset_kernel(pmd, addr); clear_pte_entry(kvm, pte, addr); next = addr + PAGE_SIZE; + } else { + pte = NULL; } /* * If the pmd entry is to be cleared, walk back up the ladder */ - if (kvm_pmd_huge(*pmd) || page_empty(pte)) { + if (kvm_pmd_huge(*pmd) || (pte && page_empty(pte))) { clear_pmd_entry(kvm, pmd, addr); next = pmd_addr_end(addr, end); if (page_empty(pmd) && !page_empty(pud)) {