From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qk0-x22e.google.com (mail-qk0-x22e.google.com [IPv6:2607:f8b0:400d:c09::22e]) (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 2711621D1823C for ; Mon, 14 Aug 2017 10:41:42 -0700 (PDT) Received: by mail-qk0-x22e.google.com with SMTP id d136so54501178qkg.3 for ; Mon, 14 Aug 2017 10:44:06 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=BBoiH4xTWzH+i8WT3eXF8BUgfvDLwOo2by/Ldb9hdiA=; b=js3FJJv8neqUn2CDfAB0hWdc15423CdW/voiQlZ1sJmwFz13A6YUsETFJ0trfi0NW3 S07iFnz1hYAO4sGdB+kwGF2Yvuute0RrckuOnoEMZmm0yAKl5GnczbIUNXn7KT9ZK+b/ LloXaFplTZRP44Gt3X3MBSQByzfhGnFR05njkxuPn8Tt9zjUgSQOrZtkj+zlLQRdzm30 UYPdICmnd5P9IVhDOsGvRpAo7MnQI2/JwiEmS9tdpjOvIkL76xNqGKxCT6fWaAvif6/m IAuuFwn49vYhVwrbTLqU7mxYdQM+xDHRL9Fu6ZXNFtP9/zku0FsKbghbEREOHYAyPilC VGVg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=BBoiH4xTWzH+i8WT3eXF8BUgfvDLwOo2by/Ldb9hdiA=; b=mWgEu6QnD+xjvwIUVYhzRUYgCnJ3clxH/pR/XbVl+PAarLzwFF9W17shyfOUAkwTxA 9ftvAS4J3Ubzri2JnJ9HuOq6uszAKgQjKoIuRPbke/TGPDaJ9J5+5347xfK27SdaLBAh gcl3bGoG0yQvD09PwB/4amDXobO+GUxyzDOwhAuqR+M8w+iMLVEbbybYhx/8UZ1owP5v WUbTw198nAEILMIQnQhyBHbtr5b65N22Asev6gKRR512/ouxeoDVa35C51Cs4cjq+F+s vhAQeTAWZiqzbTn/8C0hfLbkrnORBLifeOQrX8FIFe36935PgjpXn1Md4DvBe7unSH9G hzwA== X-Gm-Message-State: AHYfb5hS0d/Ncj+WVmB+oRTbPCmMYpSBoqKi50BsW2xUuuQMeOCjtvoO Tw3dsz68DdDnyVSlRIpqSKt6P2SGhQ== X-Received: by 10.55.143.198 with SMTP id r189mr32934725qkd.7.1502732645214; Mon, 14 Aug 2017 10:44:05 -0700 (PDT) MIME-Version: 1.0 References: <42CE0497-A269-4D40-9E65-31A3CE27F197@apple.com> <3b578f09-8c29-4168-2524-49c8a2d5e210@rodsbooks.com> In-Reply-To: From: Rafael Machado Date: Mon, 14 Aug 2017 17:43:54 +0000 Message-ID: To: Andrew Fish Cc: Rod Smith , edk2-devel@lists.01.org X-Content-Filtered-By: Mailman/MimeDel 2.1.22 Subject: Re: 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: Mon, 14 Aug 2017 17:41:42 -0000 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Hi Andrew. Thanks a lot for the guidance!! Rafael R. Machado Em dom, 13 de ago de 2017 =C3=A0s 15:08, Andrew Fish escr= eveu: > On Aug 13, 2017, at 6:07 AM, Rafael Machado < > rafaelrodrigues.machado@gmail.com> wrote: > > Thanks a lot Andrew and Rod. Your comments clarified a lot. > > Just onde last question. > In case of int15/e820 and uefi getMemoryMap. Do you know If this > information os used by the bootloaders? > > > Yes it is, this is how the OS discovers the memory map. > > And do you know the format on these calls outputs? (For the getMemoryMap > the uefi Spec os clear, but didn't find anything about e820). > > > The modern version of 0xE820 is documented in the ACPI Spec owned by your > friendly UEFI Forum. ACPI Spec is here: > http://www.uefi.org/specifications. > > There are some other specs from the 1990's that may be useful for legacy > BIOS. Plug and Play BIOS Specification from 1994, and BIOS Boot > Specification from 1996. For older stuff most people use Ralf Brown's > interrupt list. You kind find all this old BIOS stuff searching the > internwebs. > > Thanks, > > Andrew Fish > > Thanks and Regards > Rafael Machado > > Em s=C3=A1b, 12 de ago de 2017 00:23, Rod Smith > escreveu: > > On Aug 11, 2017, at 6:00 AM, Rafael Machado > wrote: > > > 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. > > > If I understand you correctly, it most definitely IS possible. Most > major Linux distributions provide installation media that can boot in > either BIOS/CSM/legacy mode or in EFI/UEFI mode. Replicating what those > media do might not be the best way to go, though, since they are also > typically designed to boot when written to optical media or when written > to USB flash drives. To do this, they use a sort of "Frankenstein's > Monster" disk format, so unless you need this cross-media compatibility, > too, using the tools and procedures used to create these installation > media would be overkill and would create something that's overly > complex. These media do illustrate the practicality of what you're > suggesting -- or at least, what I *BELIEVE* you're suggesting. If I've > misinterpreted, please clarify your needs. > > The OS in this case is Linux, and the bootloader is Grub or Syslinux. > > > A single GRUB (or SYSLINUX) binary will not do the job; however, there > are both BIOS and EFI builds of both GRUB and SYSLINUX. The details of > what you'd do would depend on the boot medium (hard disk, USB flash > drive, optical disc, etc.); however, broadly speaking you need to write > both BIOS-mode and EFI-mode versions of your chosen boot loader to the > boot medium, with suitable configuration files in appropriate locations. > > Both GRUB and SYSLINUX are boot loaders that can load a Linux kernel > into memory. The Linux kernel, in turn, does not need to be built for > either BIOS or EFI environments; the same kernel binary will work in > either environment. (One partial exception is that there's a feature > known as the EFI stub loader that turns the Linux kernel into its own > EFI boot loader. If you wanted to use this feature, it would obviously > need to be compiled into the kernel. GRUB does not require this feature, > though, and its presence will not interfere with the kernel being booted > on a BIOS-based computer. Thus, you probably don't need to worry about > it for your purposes. I mention it simply so you don't think it's an > issue if you read something about it elsewhere.) > > -- > Rod Smith > rodsmith@rodsbooks.com > http://www.rodsbooks.com > _______________________________________________ > edk2-devel mailing list > edk2-devel@lists.01.org > https://lists.01.org/mailman/listinfo/edk2-devel > > _______________________________________________ > edk2-devel mailing list > edk2-devel@lists.01.org > https://lists.01.org/mailman/listinfo/edk2-devel > >