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=-2.0 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 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 A8EDAC3F2CD for ; Mon, 2 Mar 2020 16:54:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 767AB222C4 for ; Mon, 2 Mar 2020 16:54:21 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="iUqLGPeN" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727111AbgCBQyV (ORCPT ); Mon, 2 Mar 2020 11:54:21 -0500 Received: from mail-qt1-f193.google.com ([209.85.160.193]:38790 "EHLO mail-qt1-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727104AbgCBQyV (ORCPT ); Mon, 2 Mar 2020 11:54:21 -0500 Received: by mail-qt1-f193.google.com with SMTP id e20so453728qto.5; Mon, 02 Mar 2020 08:54:20 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=sender:from:date:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=5Er//MGifVyaYeTMJqwNXPSSyalhUWucIS7ZB5vkA+Y=; b=iUqLGPeNxhFiovwOSVPRTmLnahvGI3uCtaZVQPaB9dZTy3CNorMPrDeeyasbSTAdn3 d6NLuvRDEsHcLpLWRVBx6C46BqJtJQ8nQ6ies53CMIYz3AUbHaocETRKg9S17geaM9Wi ROzHDug+gJGhVycaS0WmGR3YQEHTz+xUL07C7Taw5DRftc2DtiVqGlO/qkP6jXtRryXg PuIWHSjbqHQEp4EWztDF3joTqEazGHHocGyKRxmaMjSxHqRyEQd6u/IqGehvdwQDhpt6 y6Qf1JYujjmk7Pe1zI4/vOY1+IdgEecY//XTVJNu5UC/tvTqvkK262pFMX2YmTXNOMq+ kZ/Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:from:date:to:cc:subject:message-id :references:mime-version:content-disposition:in-reply-to:user-agent; bh=5Er//MGifVyaYeTMJqwNXPSSyalhUWucIS7ZB5vkA+Y=; b=F5IPWbUBXD1tfVPbTfqrezNrBAQ8gVIB79zZQ6F1alNGNFPNiIy0/DdgrqhdVuzXEj IY+z2PnA4Ysbsn+k31dqfvS/4jUEm/kKiTnt3K28oMvzZ40oFOFG6/+Ybu1tFncSjPbu rnRh/l2QPF+7HsWtbyFXKBUwpCKxEHX4d975CYRL2LF2bNxwbo7nGsQ7c92eG0Zw0viz qs/w67rmEqhdiDeRNdWvOtvfk6ZVwNHxh5x0l5qEtvKqO/JdZuWPPB6qbPaGoNklm1Py nhUQY5yUSDjWYt1CQGHpkz7YBs52YfjKq+NiNJQWIZuIyPh60iPkrRawE2eAdZTEMOh6 01oQ== X-Gm-Message-State: ANhLgQ2OCsMKRV1UFMM1gOmggQ4iYiJo4NvRQnMj+RCcrnnL9xaCgaHd sDntoeHAW60WLpk5PrMwUps= X-Google-Smtp-Source: ADFU+vvHA1ynAXRGcX+6ZpxeHP5uAZ4A9yzsOaq8OGAG42LZ/ltBJ8i2vFhWosTzewEZkmXOaUl5OQ== X-Received: by 2002:ac8:6b99:: with SMTP id z25mr612217qts.256.1583168059478; Mon, 02 Mar 2020 08:54:19 -0800 (PST) Received: from rani.riverdale.lan ([2001:470:1f07:5f3::b55f]) by smtp.gmail.com with ESMTPSA id h13sm10582440qtu.23.2020.03.02.08.54.19 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 02 Mar 2020 08:54:19 -0800 (PST) From: Arvind Sankar X-Google-Original-From: Arvind Sankar Date: Mon, 2 Mar 2020 11:54:17 -0500 To: Ard Biesheuvel Cc: Arvind Sankar , linux-efi , the arch/x86 maintainers , Linux Kernel Mailing List Subject: Re: [PATCH 3/5] efi/x86: Make efi32_pe_entry more readable Message-ID: <20200302165359.GA2599505@rani.riverdale.lan> References: <20200301230436.2246909-1-nivedita@alum.mit.edu> <20200301230436.2246909-4-nivedita@alum.mit.edu> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-efi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-efi@vger.kernel.org On Mon, Mar 02, 2020 at 08:49:17AM +0100, Ard Biesheuvel wrote: > On Mon, 2 Mar 2020 at 00:04, Arvind Sankar wrote: ... > > call 1f > > -1: pop %ebp > > - subl $1b, %ebp > > +1: pop %ebx > > + subl $1b, %ebx ... > > > > + movl %ebx, %ebp // startup_32 for efi32_pe_stub_entry > > The code that follows efi32_pe_stub_entry still expects the runtime > displacement in %ebp, so we'll need to pass that in another way here. > > > jmp efi32_pe_stub_entry Didn't follow -- what do you mean by runtime displacement? efi32_pe_stub_entry expects the runtime address of startup_32 to be in %ebp, but with the changes for keeping the frame pointer in %ebp, I changed the runtime address to be in %ebx instead. Hence I added that movl %ebx, %ebp to put it in %ebp just before calling efi32_pe_stub_entry. That should be fine, no?