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=-13.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=ham 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 43C97C433FF for ; Mon, 29 Jul 2019 09:46:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 170172073F for ; Mon, 29 Jul 2019 09:46:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1564393581; bh=b+tI6bHDOwG6E+/q3x1v00SGmcoiUnOU93dUmX8r/cA=; h=Subject:To:Cc:References:From:Date:In-Reply-To:List-ID:From; b=z6x9Vi19TY86mtPB9ulStpeaNuiXEDMDYPoeSGqKO9b5svmutobafUR3m61zi44AE LKxYdI40gmgzD1O2nfTsEPCxAmIXtS/ZvhOnsCUenQwmcnR/6I2yhKEf61nJzLGvEU BfLgl9ycYgbSobM8I9QzCAtgVxfJ3Wm/by6rr9UM= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726524AbfG2JqT (ORCPT ); Mon, 29 Jul 2019 05:46:19 -0400 Received: from foss.arm.com ([217.140.110.172]:40846 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726129AbfG2JqT (ORCPT ); Mon, 29 Jul 2019 05:46:19 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 8D7B8152D; Mon, 29 Jul 2019 02:46:18 -0700 (PDT) Received: from [10.1.197.61] (usa-sjc-imap-foss1.foss.arm.com [10.121.207.14]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id BF3FB3F694; Mon, 29 Jul 2019 02:46:17 -0700 (PDT) Subject: Re: [PATCH] KVM: arm64: mark expected switch fall-through To: Matteo Croce , linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu Cc: Catalin Marinas , Will Deacon , linux-kernel@vger.kernel.org References: <20190728225311.5414-1-mcroce@redhat.com> From: Marc Zyngier Organization: Approximate Message-ID: Date: Mon, 29 Jul 2019 10:46:16 +0100 User-Agent: Mozilla/5.0 (X11; Linux aarch64; rv:60.0) Gecko/20100101 Thunderbird/60.8.0 MIME-Version: 1.0 In-Reply-To: <20190728225311.5414-1-mcroce@redhat.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 28/07/2019 23:53, Matteo Croce wrote: > Mark switch cases where we are expecting to fall through, > fixes the following warning: > > In file included from ./arch/arm64/include/asm/kvm_emulate.h:19, > from arch/arm64/kvm/regmap.c:13: > arch/arm64/kvm/regmap.c: In function ‘vcpu_write_spsr32’: > ./arch/arm64/include/asm/kvm_hyp.h:31:3: warning: this statement may fall through [-Wimplicit-fallthrough=] > asm volatile(ALTERNATIVE(__msr_s(r##nvh, "%x0"), \ > ^~~ > ./arch/arm64/include/asm/kvm_hyp.h:46:31: note: in expansion of macro ‘write_sysreg_elx’ > #define write_sysreg_el1(v,r) write_sysreg_elx(v, r, _EL1, _EL12) > ^~~~~~~~~~~~~~~~ > arch/arm64/kvm/regmap.c:180:3: note: in expansion of macro ‘write_sysreg_el1’ > write_sysreg_el1(v, SYS_SPSR); > ^~~~~~~~~~~~~~~~ > arch/arm64/kvm/regmap.c:181:2: note: here > case KVM_SPSR_ABT: > ^~~~ > In file included from ./arch/arm64/include/asm/cputype.h:132, > from ./arch/arm64/include/asm/cache.h:8, > from ./include/linux/cache.h:6, > from ./include/linux/printk.h:9, > from ./include/linux/kernel.h:15, > from ./include/asm-generic/bug.h:18, > from ./arch/arm64/include/asm/bug.h:26, > from ./include/linux/bug.h:5, > from ./include/linux/mmdebug.h:5, > from ./include/linux/mm.h:9, > from arch/arm64/kvm/regmap.c:11: > ./arch/arm64/include/asm/sysreg.h:837:2: warning: this statement may fall through [-Wimplicit-fallthrough=] > asm volatile("msr " __stringify(r) ", %x0" \ > ^~~ > arch/arm64/kvm/regmap.c:182:3: note: in expansion of macro ‘write_sysreg’ > write_sysreg(v, spsr_abt); > ^~~~~~~~~~~~ > arch/arm64/kvm/regmap.c:183:2: note: here > case KVM_SPSR_UND: > ^~~~ > In file included from ./arch/arm64/include/asm/cputype.h:132, > from ./arch/arm64/include/asm/cache.h:8, > from ./include/linux/cache.h:6, > from ./include/linux/printk.h:9, > from ./include/linux/kernel.h:15, > from ./include/asm-generic/bug.h:18, > from ./arch/arm64/include/asm/bug.h:26, > from ./include/linux/bug.h:5, > from ./include/linux/mmdebug.h:5, > from ./include/linux/mm.h:9, > from arch/arm64/kvm/regmap.c:11: > ./arch/arm64/include/asm/sysreg.h:837:2: warning: this statement may fall through [-Wimplicit-fallthrough=] > asm volatile("msr " __stringify(r) ", %x0" \ > ^~~ > arch/arm64/kvm/regmap.c:184:3: note: in expansion of macro ‘write_sysreg’ > write_sysreg(v, spsr_und); > ^~~~~~~~~~~~ > arch/arm64/kvm/regmap.c:185:2: note: here > case KVM_SPSR_IRQ: > ^~~~ > In file included from ./arch/arm64/include/asm/cputype.h:132, > from ./arch/arm64/include/asm/cache.h:8, > from ./include/linux/cache.h:6, > from ./include/linux/printk.h:9, > from ./include/linux/kernel.h:15, > from ./include/asm-generic/bug.h:18, > from ./arch/arm64/include/asm/bug.h:26, > from ./include/linux/bug.h:5, > from ./include/linux/mmdebug.h:5, > from ./include/linux/mm.h:9, > from arch/arm64/kvm/regmap.c:11: > ./arch/arm64/include/asm/sysreg.h:837:2: warning: this statement may fall through [-Wimplicit-fallthrough=] > asm volatile("msr " __stringify(r) ", %x0" \ > ^~~ > arch/arm64/kvm/regmap.c:186:3: note: in expansion of macro ‘write_sysreg’ > write_sysreg(v, spsr_irq); > ^~~~~~~~~~~~ > arch/arm64/kvm/regmap.c:187:2: note: here > case KVM_SPSR_FIQ: > ^~~~ > > Signed-off-by: Matteo Croce > --- > arch/arm64/kvm/regmap.c | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/arch/arm64/kvm/regmap.c b/arch/arm64/kvm/regmap.c > index 0d60e4f0af66..b376b2fdbf51 100644 > --- a/arch/arm64/kvm/regmap.c > +++ b/arch/arm64/kvm/regmap.c > @@ -178,12 +178,16 @@ void vcpu_write_spsr32(struct kvm_vcpu *vcpu, unsigned long v) > switch (spsr_idx) { > case KVM_SPSR_SVC: > write_sysreg_el1(v, SYS_SPSR); > + /* fallthrough */ > case KVM_SPSR_ABT: > write_sysreg(v, spsr_abt); > + /* fallthrough */ > case KVM_SPSR_UND: > write_sysreg(v, spsr_und); > + /* fallthrough */ > case KVM_SPSR_IRQ: > write_sysreg(v, spsr_irq); > + /* fallthrough */ > case KVM_SPSR_FIQ: > write_sysreg(v, spsr_fiq); > } > That's absolutely the *WRONG* fix. Please see [1] for the real thing. Thanks, M. [1] https://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm.git/commit/?id=3d584a3c85d6fe2cf878f220d4ad7145e7f89218 -- Jazz is not dead, it just smells funny...