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=-8.4 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,USER_IN_DEF_DKIM_WL autolearn=no 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 93329CA9EC9 for ; Mon, 4 Nov 2019 22:20:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5D170204FD for ; Mon, 4 Nov 2019 22:20:13 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="MY8yAdah" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388754AbfKDV7v (ORCPT ); Mon, 4 Nov 2019 16:59:51 -0500 Received: from mail-pl1-f194.google.com ([209.85.214.194]:40516 "EHLO mail-pl1-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388743AbfKDV7s (ORCPT ); Mon, 4 Nov 2019 16:59:48 -0500 Received: by mail-pl1-f194.google.com with SMTP id e3so6176697plt.7 for ; Mon, 04 Nov 2019 13:59:48 -0800 (PST) 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; bh=IymmwTl8Rrj9gY6nJ0vlwI8rMdE1BEoC3iBejCXtH+A=; b=MY8yAdahkSPgp2X7tfA/R8Kp3qQsk/vpyfIVoGibvQOAOpVG7dWCO1ps9OFVU/PeQ2 xmCUqqZrBtMEkwUoAmhBOgtmsVlFUtt4OCkf9ato/mDIOtSnxyqBXmTQtUkeV2KN/cEu uLETcMkI4O4qIzY5Y306Ex+gLpUkIXvuSs9qEm5UsJ2LEV2IVanDbiKUASuI1nY+mtL5 XBusqd+MqXtDJwvZY1fBBNTUs+KQ7gO7X40sMOLNuGkgG37V0sUUbLmt3BbeSAjcbBGt o5VvFFqzfhhGpTqKArM+xBeJCSm357VSXiFQchB69JrVAYDNCWNBhQSCeFCDVo42elwW 9clQ== 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; bh=IymmwTl8Rrj9gY6nJ0vlwI8rMdE1BEoC3iBejCXtH+A=; b=ijBle3N0bOuIu45tSPrfy262AEh+ScYeeBv36wT1ATzuEf5d2nq33YtRI2zvG9oS8e v/Z36BDiXjA9hXHd/LOGgiYlW9Ykuk47MbRc4QCgS0NnrOBvTV9MzZN3RAS3ztQmh5Je sSIN+C8670WvYSwV040303cygc/RgSbyLLFWwtY/cd0WP0/wF1S+FlC8Fda+kwIzit8q uw3ojFguTOYRuecotZd4+xVodPvKYhpD22dr8RgNgfQVOYOXoq05Bhn8aMLz5m8r0nDA wokKMrO7RDb48UkV90/xXRCanxqlmCT9Vd1UuLdD2u2eVgfMRcVqVEd8d2LR7N1k3hS2 6I8A== X-Gm-Message-State: APjAAAX5iXWhqeU35skpN3zbPruiK+C3EqZ86DAfh+jSM4QhNKl/Ahor lKPrERKXDLPSp9Vy81qy23+Z0LXOodDSZhV9Hb6HTA== X-Google-Smtp-Source: APXvYqyvfbe4Rk74BEZhEbgv9KmXI2oczxNxkswGRQ3YxahRRLStSKtwQ3PlZ387iT14X5dnJ3JmqJ53a+0shRWL1lM= X-Received: by 2002:a17:902:9b83:: with SMTP id y3mr29178135plp.179.1572904786995; Mon, 04 Nov 2019 13:59:46 -0800 (PST) MIME-Version: 1.0 References: <20191018161033.261971-1-samitolvanen@google.com> <20191101221150.116536-1-samitolvanen@google.com> <20191101221150.116536-14-samitolvanen@google.com> <02c56a5273f94e9d832182f1b3cb5097@www.loen.fr> In-Reply-To: From: Nick Desaulniers Date: Mon, 4 Nov 2019 13:59:35 -0800 Message-ID: Subject: Re: [PATCH v4 13/17] arm64: preserve x18 when CPU is suspended To: Sami Tolvanen Cc: Marc Zyngier , Will Deacon , Catalin Marinas , Steven Rostedt , Masami Hiramatsu , Ard Biesheuvel , Dave Martin , Kees Cook , Laura Abbott , Mark Rutland , Jann Horn , Miguel Ojeda , Masahiro Yamada , clang-built-linux , Kernel Hardening , linux-arm-kernel , LKML Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Nov 4, 2019 at 1:38 PM Sami Tolvanen wrote: > > On Mon, Nov 4, 2019 at 5:20 AM Marc Zyngier wrote: > > > ENTRY(cpu_do_suspend) > > > mrs x2, tpidr_el0 > > > @@ -73,6 +75,9 @@ alternative_endif > > > stp x8, x9, [x0, #48] > > > stp x10, x11, [x0, #64] > > > stp x12, x13, [x0, #80] > > > +#ifdef CONFIG_SHADOW_CALL_STACK > > > + str x18, [x0, #96] > > > +#endif > > > > Do we need the #ifdefery here? We didn't add that to the KVM path, > > and I'd feel better having a single behaviour, specially when > > NR_CTX_REGS is unconditionally sized to hold 13 regs. > > I'm fine with dropping the ifdefs here in v5 unless someone objects to this. Oh, yeah I guess it would be good to be consistent. Rather than drop the ifdefs, would you (Marc) be ok with conditionally setting NR_CTX_REGS based on CONFIG_SHADOW_CALL_STACK, and doing so in KVM? (So 3 ifdefs, rather than 0)? Without any conditionals or comments, it's not clear why x18 is being saved and restored (unless git blame survives, or a comment is added in place of the ifdefs in v6). -- Thanks, ~Nick Desaulniers