coreboot September 2017

coreboot@coreboot.org

57 participants
132 discussions

Re: [coreboot] What GPU are you using on KGPE-D16
by Taiidan＠gmx.com 04 Sep '17

04 Sep '17

On 09/04/2017 10:44 PM, Iru Cai wrote: > Hi, > > I've just flashed the most recent coreboot with Linux payload on my > KGPE-D16. However, there're some problems with GPU. > > I have an RX550, but it seems that amdgpu has bug with AMD-Vi which I found > in some mailing list (), and > it still doesn't work after I use amd_iommu=fullflush, and using > amd_iommu=off will make the machine not able to find USB devices. > > And I have a GTX750, but xf86-video-nouveau doesn't work on this Maxwell > card. > > Iru I use Geforce GTX 780 but I only use it to game in a windows VM - I used to have problems with it being stuck in S3 but those seem to be gone now (bad nvidia software). It is a holdover before I knew about the annoying code 43 "bug" that I burned hours working around. I would consult AMD's server support group for this.

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Re: [coreboot] About Paging, Realmode and what is going on
by Zoran Stojsavljevic 04 Sep '17

04 Sep '17

> Hint: on x86 it's essentially one billion instructions before you can even think about using RAM, much less loading the payload. This is why everybody using INTEL silicon do have FSP as A MUST (instead SEC+PEI). And this is why CORE CPU creations (2C+) have > 500 million gates per silicon. There gazillions of modes, which are probably only 10% used in real scenarios. All others are testing modes. And INTEL made smart investment forcing customers to pay for that (excessive silicon use/overkill). > which is to load linux from flash. It's working fine on UEFI today and I'm seeing what it takes to replace the coreboot ramstage with linux. YUP. Since no OS loader, only one/single OS instance to be actually loaded from flash. Then you don't care about AHCI, SATA, IDE and other HDD/SSD modes, also about GFX (embedded Linux) and also CSM or UEFI. No INT, no Run Time Services. You are running true ram disk, unpacked from flash as well. Zoran On Tue, Sep 5, 2017 at 1:45 AM, ron minnich <rminnich(a)gmail.com> wrote: > > > On Mon, Sep 4, 2017 at 3:41 PM Philipp Stanner <stanner(a)posteo.de> wrote: > >> >> Start the board, load the OS and go back into your flash until reboot. >> > > Just checking, but have you looked at the code to see what "start the > board" really means? Hint: on x86 it's essentially one billion instructions > before you can even think about using RAM, much less loading the payload. > > I'm guessing, by what you are saying, that you are not familiar with what > has to be done. Apologies if I am wrong :-) > > And, that said, I'm back to the old original idea, which is to load linux > from flash. It's working fine on UEFI today and I'm seeing what it takes to > replace the coreboot ramstage with linux. > > ron > > -- > coreboot mailing list: coreboot(a)coreboot.org > https://mail.coreboot.org/mailman/listinfo/coreboot >

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What GPU are you using on KGPE-D16
by Iru Cai 04 Sep '17

04 Sep '17

Hi, I've just flashed the most recent coreboot with Linux payload on my KGPE-D16. However, there're some problems with GPU. I have an RX550, but it seems that amdgpu has bug with AMD-Vi which I found in some mailing list ( https://lists.freedesktop.org/archives/amd-gfx/2017-March/006490.html), and it still doesn't work after I use amd_iommu=fullflush, and using amd_iommu=off will make the machine not able to find USB devices. And I have a GTX750, but xf86-video-nouveau doesn't work on this Maxwell card. Iru -- Please do not send me Microsoft Office/Apple iWork documents. Send OpenDocument instead! http://fsf.org/campaigns/opendocument/

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Re: [coreboot] Boot from a M.2 NVMe ssd on an ASUS KGPE-D16
by Iru Cai 04 Sep '17

04 Sep '17

On Mon, Sep 4, 2017 at 3:47 PM, BogDan Vatra <bogdan(a)kde.org> wrote: > Hi, > > Is it possible to boot from a M.2 NVMe ssd on KGPE-D16? > If not, how hard it will be to add such support, I'd like to give it a > try myself. > > I'm using Linux kernel payload with petitboot. Now SeaBIOS also supports NVMe. Yours, > BogDan. > > -- > coreboot mailing list: coreboot(a)coreboot.org > https://mail.coreboot.org/mailman/listinfo/coreboot > -- Please do not send me Microsoft Office/Apple iWork documents. Send OpenDocument instead! http://fsf.org/campaigns/opendocument/

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About Paging, Realmode and what is going on
by Philipp Stanner 04 Sep '17

04 Sep '17

Dear folks and techpriests, the more I want to contribute and learn about low-level-code the less I understand, it seems. 1. cb switches the CPU immediately to Protected Mode, yet Payloads like seaBIOS work in Real Mode. Does coreboot switch the CPU always back to RM before jumping to the payload? 2. When CB switches to PM - who generates and administrates the Page Tables and where? 3. Gustavo Duarte writes <http://duartes.org/gustavo/blog/post/how-computers-boot-up/> that GRUB switches from protected mode to real mode and vice versa all the time to address >1MiB of RAM and also use the BIOS-calls. If this is true using GRUB as payload would not work, as GRUB needs to call the non-existent BIOS, right? 4. Once CB is in PM it can't access physical addresses anymore? It doesn't need to, too? 5. PM means RAM-access is only possible through virtual addresses which are translated by the MMU using the Page Tables. This question is similar to [2.]: If coreboot generates the Page Tables and the payload would start in PM as well (is this even possible? At least the Linux-Kernel has entry points for RM and PM) this would mean the payload needs to use the Page Tables generated by CB. That wouldn't be a problem as they're linked in the register CR3 anyways? And an unimportant bonus question: * Why does every modern CPU still start in RM? I do get the compatibility problem, but on the other hand: Do you need it for anything beside booting MS-DOS on your Ryzen? Is it really impossible for AMD and Intel to create a new CPU-generation with the x86-instruction set without RM, 16-bit-registers and 20-bit-mode registers like CS, SS etc. No modern OS uses bios calls. No CPU is ever switched to RM again after booting up. They should get rid of this old stuff. Would be cool if someone could put this in its true light. Thanks, Philipp

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INT 13, real mode, block write commands and coreboot
by ingegneriaforense＠alice.it 04 Sep '17

04 Sep '17

Hello guys, First of all I want to thank everyone for the answers, suggestions and links you have sent me. Maybe I was wrong to ask my questions without clarifying the problem I'm analyzing, leaving you doubts about why I did some sort of questions about INT13, real mode, and so on. As you well know, when connecting a memory device (hard drive, USB stick) to a PC, user data may be subject to change. Just think of the variation under the "date modified" field of the timestamp of a file. In the forensic field, this is not accepted. As a result, it is necessary to capture the image of the suspect drive, frozen at the time of the police seizure. For this reason, devices known as Write Blocker are used, which allow the acquisition of information on a drive without creating the possibility of accidentally damaging (writing) the drive contents. I'm studying the implementation of such a device on a PC. Actually, the writing block at kernel level at this time has been resolved. But there remains the doubt that, for any accidental event (that i don't know), the suspect device may be affected by user data. For this reason I asked, in my previous email, if there is interaction between BIOS and KERNEL. Correctly Zoran, adding the picture, has shown that there may be cases where the Kernel grants the BIOS the ability to perform some services (I think using the INT13). Then I ask you: is there a way to disable this BIOS function? More precisely, coreboot can be set to avoid receiving commands from GRUB and Ubuntu KERNEL? I hope I've been clear this time. Thanks for your patience Best Regards. Vincenzo. Forensic Consultant Tribunale di Lecce Studio: Strada di Garibaldi - Contrada Paradisi 73010 Lequile (LE) cell: 339.7968555 skype: vincenzo.di_salvo

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Re: [coreboot] Boot from a M.2 NVMe ssd on an ASUS KGPE-D16
by Taiidan＠gmx.com 04 Sep '17

04 Sep '17

On 09/04/2017 03:59 AM, BogDan Vatra wrote: > Hi, > > But grub doesn't see it at all (I boot grub from another hdd to check it :) ) > > BogDan. Hmm what devices does grub see and what version are you using?

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Re: [coreboot] Boot from a M.2 NVMe ssd on an ASUS KGPE-D16
by Taiidan＠gmx.com 04 Sep '17

04 Sep '17

On 09/04/2017 03:47 AM, BogDan Vatra wrote: > Hi, > > Is it possible to boot from a M.2 NVMe ssd on KGPE-D16? > If not, how hard it will be to add such support, I'd like to give it a > try myself. > > Yours, > BogDan. > Use the grub payload instead of the SeaBIOS payload. (directions on how to add a grub .cfg that loads grub cfgs from local disk are on the wiki)

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Boot from a M.2 NVMe ssd on an ASUS KGPE-D16
by BogDan Vatra 04 Sep '17

04 Sep '17

Hi, Is it possible to boot from a M.2 NVMe ssd on KGPE-D16? If not, how hard it will be to add such support, I'd like to give it a try myself. Yours, BogDan.

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INT 13, real mode, block write commands and coreboot
by Vincent Legoll 03 Sep '17

03 Sep '17

Why don't you use another arch computer to dump the usb key content into a file, you won't have to wonder if it got modified by a BIOS. A raspberry pi or any other such SBCs will do just fine for that. Plug it in, dump it without mounting any eventual partitions, and you're done. You can derive from threre for other interfaces like SATA... -- Vincent Legoll

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coreboot September 2017