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[209.132.180.67]) by mx.google.com with ESMTP id q2-v6si3976255plh.485.2018.08.03.09.39.55; Fri, 03 Aug 2018 09:40:10 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; dkim=pass header.i=@google.com header.s=20161025 header.b=vqchevp0; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=REJECT sp=REJECT dis=NONE) header.from=google.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728598AbeHCSfS (ORCPT + 99 others); Fri, 3 Aug 2018 14:35:18 -0400 Received: from mail-pg1-f195.google.com ([209.85.215.195]:36350 "EHLO mail-pg1-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727339AbeHCSfS (ORCPT ); Fri, 3 Aug 2018 14:35:18 -0400 Received: by mail-pg1-f195.google.com with SMTP id h12-v6so3091809pgs.3 for ; Fri, 03 Aug 2018 09:38:15 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc:content-transfer-encoding; bh=SMSiMZFV2xmqIyEx2X/LLari/l23gt20gJWmoc5OjSs=; b=vqchevp08TNUf+W43vibFh4Lml9nbon5lz2Yc/c5qeC3tSn10uefS32HGuGkzUmzOh o8iqDX5cuMM2BkviIwBYGbYF+LG5YfR6WVzCWOgE1TkogR8C2N2axww77oWsqSPf93ge 0TnOjHQfQWPlzEt+2EVgdaf41XApMG6xUlBgtrwGLYH9AG/ximNxPN7A3YluMV3yG/jf 4ZV+uNlj0NMWlFcA5ncQXfkTK4UPINjYX+nd6M4c3GinIQ8zRxy4ZArgE3R1Bad/jdfi ZN+/8BxcY4x2eqdu9AkJzCaF7ozhIhymWjNjgDkCEibiDUYRZjDb8hpc983If+QadAii FN/Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc:content-transfer-encoding; bh=SMSiMZFV2xmqIyEx2X/LLari/l23gt20gJWmoc5OjSs=; b=m+NhWJWKbX8TY75/6GOpB5apJ/yHfXdcPTbaLS/R9RN42W7AD2zHsHqHG7nQSCirGN vZOOY5ENOMLK0qNZW3aD3CR3KwFckRtgUF5MarDiVTwcA8n0EZNVXvltcApJADS3kA69 6NjFLlKOFmkEwGeu1tVEbTqBbjV3CDuW+q31j3b/py3M4eOSSZE2mHPxuS/PkoId3sII 3rj5Xn/gv/uGm7XrMZCFhHsp5ZJJjKwdzp8/B2S7OjA+jGy6yLBw992TPvoN7A+Yz5UZ lka6MhKpvtzSlpksLgOOdaIMAnY21TOzS4hyMKhbV88A1W5QPtjR/4ivavKYtZgLQ2te LoUg== X-Gm-Message-State: AOUpUlFYOahD+caQt48m0kcqzm7EzYjfh1R6HY1JRcsqlzt1J/01Kpdt MhRYM+eLjCAg/al/wfh4f/Udl1OvMYLRfrChSm7VXw== X-Received: by 2002:a62:106:: with SMTP id 6-v6mr5430076pfb.168.1533314294547; Fri, 03 Aug 2018 09:38:14 -0700 (PDT) MIME-Version: 1.0 References: <20180803151035.238a19d2@endymion> In-Reply-To: <20180803151035.238a19d2@endymion> From: Nick Desaulniers Date: Fri, 3 Aug 2018 09:38:03 -0700 Message-ID: Subject: Re: native_save_fl() causes a warning To: jdelvare@suse.de Cc: LKML , Alistair Strachan , Matthias Kaehlcke , Arnd Bergmann , hpa@zytor.com, tstellar@redhat.com, sedat.dilek@gmail.com, jgross@suse.com, Ingo Molnar , David.Laight@aculab.com Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Aug 3, 2018 at 6:10 AM Jean Delvare wrote: > > Hi Nick, > > It seems that this linux kernel commit of yours: > > commit d0a8d9378d16eb3c69bd8e6d23779fbdbee3a8c7 > Author: Nick Desaulniers > Date: Thu Jun 21 09:23:24 2018 -0700 > > x86/paravirt: Make native_save_fl() extern inline > > introduced a new warning (with W=3D1): > > ./arch/x86/include/asm/irqflags.h:16:29: warning: no previous prototype f= or =E2=80=98native_save_fl=E2=80=99 [-Wmissing-prototypes] > extern inline unsigned long native_save_fl(void) > ^ > > Please fix it. Hi Jean, thanks for the report. David Laight also reported this warning; he tested a patch I sent him overnight. Let me guess, you're using a version of GCC < 4.9? It seems that GCC < 4.9 will produce that warning for extern inline functions without previous declarations. I'll add your Reported-By tag to the patch that I will send out in a few minutes. > Secondly, I am quite curious why you changed only native_save_fl() from > static inline to extern inline, when native_restore_fl(), > native_irq_disable() and native_irq_enable() are equally referenced by > address in arch/x86/kernel/paravirt.c and thus should suffer from the > same problem. Can you explain? This is a good point. With native_save_fl, we were not able to boot the kernel at all. Maybe this was called from the boot sequence (maybe Juergen knows more)? It seems that the other functions aren't preventing us from booting, but maybe exercising other paths in paravirt would expose such an issue? Or maybe paravirt doesn't have the same calling convention requirements for those functions? Is there a standard testing procedure for paravirt? I'd be happy to try it to see if we can expose more things that should have the same cleanup. --=20 Thanks, ~Nick Desaulniers