From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm0-x22f.google.com (mail-wm0-x22f.google.com [IPv6:2a00:1450:400c:c09::22f]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by ml01.01.org (Postfix) with ESMTPS id 458C71A1DF6 for ; Fri, 9 Sep 2016 05:10:23 -0700 (PDT) Received: by mail-wm0-x22f.google.com with SMTP id w12so12007592wmf.0 for ; Fri, 09 Sep 2016 05:10:23 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=QkEhXLsmDIEnyv3vgNu/mzM8zUvnPbZAyo9l0HUgSL4=; b=DBO3ahT2y+d8RTde8ryuSftOlxlzA6/FIjUKy/wMkB66xRCYUPTp61SEAc92cBvF+F sD4WpE8eMPTBb/z8aLMDid6QiGYFXoFwvoq/UsdXPp/hXoD4EK/ZadIiG1ujYd9oSLZL u9jLpLxWQzT4hW/iyn9wcMjSoxIMfkv4Hf6po= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=QkEhXLsmDIEnyv3vgNu/mzM8zUvnPbZAyo9l0HUgSL4=; b=b+OVrEfQJWurXJ/am9O6/pkVAcCOjeur0tvntAcrawjK+rYHXR7VL7ZIu7alF/5Ypu bIviJqQQav5LwwMIKl6iQtrhs2DQmTA5p0UKI0TkfNr5h+I7MwwFnH6ZXh99/nrn6JO1 0dCm5+usFQ/c0G3VgQReOxlHMdUN4619oMHM/lW5E3o6UO14IDjK8yaXAHNSEYjtM50O P/j0bjVpDSnIpcRVC9cCCPPh1QhkypvDUD82LXd9XrVL85pET+FGewpgc2VXFZvZtNkL a8La55HAXIVgmwu3Hals2upKWZGDiHMx/Lffao0K4N0KLzaW+7qPd2wzu5fIrDS5HFTW Ah0g== X-Gm-Message-State: AE9vXwNE+zVliNCJ41AH/4WpJJToI8oXkTZSfvQouaxwuiGB1VPE4GTnHGUQRi8AD4cvseS+ X-Received: by 10.28.52.210 with SMTP id b201mr1229487wma.32.1473423021863; Fri, 09 Sep 2016 05:10:21 -0700 (PDT) Received: from bivouac.eciton.net (bivouac.eciton.net. [2a00:1098:0:86:1000:23:0:2]) by smtp.gmail.com with ESMTPSA id bc10sm3083649wjc.32.2016.09.09.05.10.20 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 09 Sep 2016 05:10:21 -0700 (PDT) Date: Fri, 9 Sep 2016 13:10:19 +0100 From: Leif Lindholm To: Ard Biesheuvel Cc: edk2-devel-01 , "Gao, Liming" Message-ID: <20160909121019.GO16080@bivouac.eciton.net> References: <1473405686-5465-1-git-send-email-ard.biesheuvel@linaro.org> <20160909111810.GM16080@bivouac.eciton.net> MIME-Version: 1.0 In-Reply-To: User-Agent: Mutt/1.5.23 (2014-03-12) Subject: Re: [PATCH] MdePkg/BaseLib AARCH64: terminate stack frame list on stack switch X-BeenThere: edk2-devel@lists.01.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: EDK II Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 09 Sep 2016 12:10:23 -0000 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline On Fri, Sep 09, 2016 at 01:03:59PM +0100, Ard Biesheuvel wrote: > On 9 September 2016 at 12:18, Leif Lindholm wrote: > > On Fri, Sep 09, 2016 at 08:21:26AM +0100, Ard Biesheuvel wrote: > >> When switching to the DXE phase stack, set the frame pointer to zero so > >> that code walking the stack frame will not try to access stack frames\ > > > > Trailing '\'. > > > >> belonging to the old stack. > > > > Do you mean that code will check for zero and stop processing, or that > > it will be accessing rubbish instead of parsing a valid-looking frame? > > I don't understand this question. If it is zero, it will stop > processing. If it is not zero, it will proceed, and potentially > traverse stack frames in memory that is now owned by someone else. Which was exactly what I was asking :) So no need to change (but drop the '\'). / Leif