From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received-SPF: Pass (sender SPF authorized) identity=mailfrom; client-ip=209.132.183.28; helo=mx1.redhat.com; envelope-from=lersek@redhat.com; receiver=edk2-devel@lists.01.org Received: from mx1.redhat.com (mx1.redhat.com [209.132.183.28]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ml01.01.org (Postfix) with ESMTPS id 536C02205B90A for ; Thu, 11 Jan 2018 01:57:47 -0800 (PST) Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 8E175C057F9F; Thu, 11 Jan 2018 10:02:55 +0000 (UTC) Received: from lacos-laptop-7.usersys.redhat.com (ovpn-120-14.rdu2.redhat.com [10.10.120.14]) by smtp.corp.redhat.com (Postfix) with ESMTP id 897B45D70B; Thu, 11 Jan 2018 10:02:54 +0000 (UTC) From: Laszlo Ersek To: Liming Gao Cc: edk2-devel@lists.01.org, Andrew Fish References: <20180110152432.15964-1-liming.gao@intel.com> <25a13df1-e2f9-ce8e-e580-4905f8e45557@redhat.com> Message-ID: Date: Thu, 11 Jan 2018 11:02:53 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.5.2 MIME-Version: 1.0 In-Reply-To: <25a13df1-e2f9-ce8e-e580-4905f8e45557@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.32]); Thu, 11 Jan 2018 10:03:00 +0000 (UTC) Subject: Re: [Patch 0/7] EDK2: Enable XCODE5 tool chain with NASM source X-BeenThere: edk2-devel@lists.01.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: EDK II Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 11 Jan 2018 09:57:47 -0000 Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit On 01/11/18 10:54, Laszlo Ersek wrote: > Liming, > > On 01/10/18 16:24, Liming Gao wrote: >> 1. Use nasm source file for X86 tool chain, then ASM and S file can be removed. >> 2. Update Nasm source file to resolve the absolute addressing. >> 3. Verify OVMF IA32, IA32X64 and X64 boot to shell functionality with XCODE5 >> Here is build command. >> build -p OvmfPkg\OvmfPkgIa32X64.dsc -a IA32 -a X64 -DSMM_REQUIRE=TRUE >> -DSECURE_BOOT_ENABLE=TRUE -DUSE_OLD_SHELL >> build -p OvmfPkg\OvmfPkgIa32.dsc -a IA32 -a X64 -DSMM_REQUIRE=TRUE >> -DSECURE_BOOT_ENABLE=TRUE -DUSE_OLD_SHELL >> build -p OvmfPkg\OvmfPkgX64.dsc -a IA32 -a X64 -DSMM_REQUIRE=TRUE >> -DSECURE_BOOT_ENABLE=TRUE -DUSE_OLD_SHELL >> 4. Known limitation is XCODE5 doesn't support HII resource section generation. >> So, new UEFI shell application tftp can't be used. Old shell is used. > > After sleeping on this, I got a question: is there a public bug report > in the clang / llvm bug tracker about this shortcoming? It would be nice > to reference it in the commit messages. > > The main reason I'm asking this is because these workarounds include > more and more DB / DW / DD / DQ mnemonics in the NASM source files. One > of the original promises of NASM was that we could cut down on the > binary representation of x86 instructions, just write real assembly > code. This was in part enabled by NASM supporting multi-mode assembly > files, such that mode transitions (e.g. from real mode to protected mode > to long mode) could still be implemented in a human-readable assembly file. > > So this workaround is a step back in that regard (i.e., for readability > and future updates). I agree we are sometimes forced to do such things > to support all the toolchains we target, but it would be nice to have > proof that the clang / llvm developers *intend* to fix this (possibly in > the next major release of XCODE -- I'm not sure). So a public bug report > that we could reference in the commit messages would be great. Nevermind, I just read Mike's comments and the new approach; it's much better! (Still, if we have an XCODE bug report, it would be nice to reference that in the commit messages.) Thanks! Laszlo