From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qk0-x22b.google.com (mail-qk0-x22b.google.com [IPv6:2607:f8b0:400d:c09::22b]) (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 2B68A21D490ED for ; Fri, 11 Aug 2017 05:57:54 -0700 (PDT) Received: by mail-qk0-x22b.google.com with SMTP id x191so19643479qka.5 for ; Fri, 11 Aug 2017 06:00:14 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:from:date:message-id:subject:to; bh=K+SV4WVcxP04Uc2iDteFb95pdWeUXJiJe+TFqZPM2qo=; b=UPR9j3l6vWq9BlPTSVqVBPXzomgTNteVq5UC4Owo49xaL3dgfWv61cOn74AjLLVexD Qftup2byRDXdgsO911u8OztFLqSgYHGZ1bGFDEcMRWP29t/6b79iS9dSglzXqTWeHBrH ixayeUhYQ+xtGegh0Eo3QOGZV4wTCCnc0MYD1cnMn1Hej2WPva09hgBIyAL+LbwqCv7o /GutiWFnWq4yYeDaFu8xarnJkJUJkUnHVNliFTjitOuOzj58r2+5zfv12CGPfFIBOETc nwMU7Dfz7EeVIUugtiErB3WtmYNiCjlnJ9xHzldtp5yzVtrTC0xYwz1Ch5iK+zp/rGXs yvUQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:from:date:message-id:subject:to; bh=K+SV4WVcxP04Uc2iDteFb95pdWeUXJiJe+TFqZPM2qo=; b=XyEamR0EsHNaDr2k8WeXskGcQABeaOjNpu/a12lK2T4W+Nzbz0xcn2gMdDreTDqxfw 4JP+MRMz3rQ08b+OsmdjimZlmkBOZaSFeKVUaVBzpvFtXW13bAOQItNC0NsJKXKeUcza Qovjj4BtppVjwY2+xWDngKTscteb9abJObvTdtssW8k3OCT3Z64q4Kz3zjw3/1mWHIf5 8YsSTYKRSUAPYcxX5XMHQj4uWBG2vHNzQNYGAyzETxFRRw+uDW55/YYh8sR6cECAHElx G/BntqCVBW8xFrgvQDK9YwYvIX5DmhNZti9xVfDO9z+YkZ805bWct5msTCTuvr1Cd+7G RC9g== X-Gm-Message-State: AHYfb5i8TqLNz0wPWmqI4YlBGmXTBS3OoJlmLYrfVkpaurgTGLHl0T5O 1yZW4yBMFULO12A7NVDcQNFB85d5/g== X-Received: by 10.55.82.3 with SMTP id g3mr19502798qkb.23.1502456413359; Fri, 11 Aug 2017 06:00:13 -0700 (PDT) MIME-Version: 1.0 From: Rafael Machado Date: Fri, 11 Aug 2017 13:00:02 +0000 Message-ID: To: "edk2-devel@lists.01.org" X-Content-Filtered-By: Mailman/MimeDel 2.1.22 Subject: What Bios data is sent to the Bootloader/OS ? X-BeenThere: edk2-devel@lists.01.org X-Mailman-Version: 2.1.22 Precedence: list List-Id: EDK II Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 11 Aug 2017 12:57:54 -0000 Content-Type: text/plain; charset="UTF-8" Hi everyone I have a question that probably some guys here can help. The scenario I have, is that I need to create a OS image that must be able to boot at a UEFI system (with no csm module), and at a legacy bios system. My fist thought is that this is not possible. The first thing I see that is different is the what the memory map is presented to the Bootloader/OS. At legacy bios the int15/0xE820 is used, and at a UEFI bios the GetMemoryMap() from the boot service is used. Is my understanding correct? Besides that. Is there any other change that could not make it possible to create a single BootloaderLoader/OS image able to boot on a UEFI BIOS(with no CSM) and on a Legacy Bios ? I would like to create a list or arguments to talk with my client that requested this, in case this is really not possible. The OS in this case is Linux, and the bootloader is Grub or Syslinux. Thanks and Regards Rafael R. Machado