From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from list by lists.gnu.org with archive (Exim 4.71) id 1clHVD-0000gF-FM for mharc-grub-devel@gnu.org; Tue, 07 Mar 2017 10:58:19 -0500 Received: from eggs.gnu.org ([2001:4830:134:3::10]:48893) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1clHVB-0000eg-O6 for grub-devel@gnu.org; Tue, 07 Mar 2017 10:58:18 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1clHVA-00087y-Un for grub-devel@gnu.org; Tue, 07 Mar 2017 10:58:17 -0500 Received: from mail-wr0-x22f.google.com ([2a00:1450:400c:c0c::22f]:36215) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1clHVA-00087S-Od for grub-devel@gnu.org; Tue, 07 Mar 2017 10:58:16 -0500 Received: by mail-wr0-x22f.google.com with SMTP id u108so4478539wrb.3 for ; Tue, 07 Mar 2017 07:58:15 -0800 (PST) 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=F4nVIcI1NASr0Th0QeZsvkRXLDzkaD1TIOIgN60JLP0=; b=g/TPZGWmfT+9YbXQ4+pPyV5obqynW68gTM4y3Ebp7zW/t5B/r9X991NQhE7Lx3xrMK Yt2TUrR0p9H2g2NyG1ML//nV4a3ndxb8iuxgnjuz0VmqVmd4KUtrZLO46mWwNTB37bpy 1AzFsD8UWNw1jAOGJYjos3OkLWERnpFzH14uw= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=F4nVIcI1NASr0Th0QeZsvkRXLDzkaD1TIOIgN60JLP0=; b=BzOQcxu2f/LCga7P6Ohxo6pgml9v7eIlo7nnrQhLL3VpwY8Lyb26k6Y8wlcnsdISiV CNHxJptBAoj/Z55NW7gOvKBaP31V5vxplWOGTPs6uZ5DDvfwe1ulkMpYxlzIww95/lYR SpJW2nR+I3caTZPDSPPvmcMxL3ynlwj6FH4S/XxDVvktj0e3QFVlD7sRPudKO0kEzr0I VUlibN15aO6BAM7QAe9RbAm270ASXxrdR4mQS70PJG0twsuKOCeWe+98btQvhh9GoEs2 JSpJkbWGD5qexXvT05JdOeE85yymn6wc/pPo/i1iDdFEE4TByn+XBCwELC1qOjOAjZ0W hcoQ== X-Gm-Message-State: AMke39n1bXeWno0Vrv16lK5zNb16r6c51x570nvT5VO6+XoRKCZTJgC47BcTf0368MTHkmBH X-Received: by 10.223.170.70 with SMTP id q6mr1022476wrd.162.1488902294116; Tue, 07 Mar 2017 07:58:14 -0800 (PST) Received: from bivouac.eciton.net (bivouac.eciton.net. [2a00:1098:0:86:1000:23:0:2]) by smtp.gmail.com with ESMTPSA id m186sm13186510wmd.21.2017.03.07.07.58.13 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 07 Mar 2017 07:58:13 -0800 (PST) Date: Tue, 7 Mar 2017 15:58:11 +0000 From: Leif Lindholm To: The development of GNU GRUB Cc: yanjianlong Subject: Re: Grub2: add UEFI support for accessing memory address above 4GB. Message-ID: <20170307155811.GM16034@bivouac.eciton.net> References: <0F096E795C1FFC47A7AE6BB0F7A9C1764BDD05B1@nkgeml513-mbs.china.huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <0F096E795C1FFC47A7AE6BB0F7A9C1764BDD05B1@nkgeml513-mbs.china.huawei.com> User-Agent: Mutt/1.5.23 (2014-03-12) X-detected-operating-system: by eggs.gnu.org: Genre and OS details not recognized. X-Received-From: 2a00:1450:400c:c0c::22f X-BeenThere: grub-devel@gnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: The development of GNU GRUB List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 07 Mar 2017 15:58:18 -0000 On Tue, Mar 07, 2017 at 01:55:01AM +0000, Yufuping wrote: > Who can add the new feature for grub2: > Add UEFI support for accessing memory address above 4GB. Presumably you mean for x86_64? Since GRUB supports all 5 architectures currently supported by the UEFI specification, 3 of which are 64-bit, it is useful to be a bit more precise. > When using grub2 as PXE downloading engine, grub2 can get initrd > file from network and put it to memory above 4GB. I can think of nothing particularly related to PXE here. The x86_64 port currently sets GRUB_EFI_MAX_USABLE_ADDRESS to 0xffffffff or 0x7fffffff, depending on toolchain configuration. ARM64 sets it to 0xffffffffffffULL, and that works fine. I seem to recall that the x86_64 port was being restricted due to known bad firmware encountered in the past. It could be that it would be worth adding an option to configure for enabling access to higher addresses, alternatively for retaining compatibility with the broken systems. > The feature should support UEFI BIOS boot mode. I do not understand this statement. / Leif