Messages in this thread | | | Subject | Re: [PATCH] firmware: export x86_64 platform flash bios region via sysfs | From | Hans-Gert Dahmen <> | Date | Thu, 24 Jun 2021 13:20:28 +0200 |
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On 23.06.21 14:40, gregkh@linuxfoundation.org wrote: >> On Wed, Jun 23, 2021 at 02:17:54PM +0200, Hans-Gert Dahmen wrote: >> Hi, >> Yes. The window is part of the DMI interface and the south bridge or PCH >> converts the bus cycles to SPI reads. It is because this region contains the >> reset vector address of your CPU and the very first instruction it executes >> after a reset when the internal setup is done will actually be loaded from >> the serial SPI bus. It is AFAIK part of AMD's original 64-bit specification. > The point is that you will never be able to do this for all devices. > You should ONLY be allowed to have this module bind to the hardware that > you KNOW it will work with. > > So please work off of a DMI table, or some such hardware description, > instead of just blindly enabling it for all systems.
I was referring to the DMI/QPI/PCI interface that connects the ICH/PCH/south bridge to the CPU. I have gone through all datasheets of intel ICH and PCH and they state that the address range from 0xff000000 through 0xffffffff is a fixed mapping that cannot be changed (no BAR) except for the original ICH (dating back to 1999) where the window is only 8MB. The original ICH is for 32-bit systems only so all 64-bit Intel systems that exist have this feature. I have talked to somebody who works with future Intel hardware and the person indicated that it is not likely to change.
This is why I made the module depend on X86_64. I still have to do the same complete research for AMD systems which is a little harder to do, so I am proposing to check if the root complex has Intel's vendor ID and only load the module on 64-bit Intel systems until I can confirm the same behavior for all 64-bit AMD systems. Then I could check if the root complex is Intel or AMD. Would that suffice as "some such hardware description"?
Here are my public sources:
ICH0 Datasheet Chapter 6.3 and Table 6-5 https://www.tautec-electronics.de/Datenblaetter/Schaltkreise/FW82801AA.pdf
ICH2 Datasheet Chapter 6.4 and Table 6-4 https://www.intel.com/content/dam/doc/datasheet/82801ba-i-o-controller-hub-2-82801bam-i-o-controller-hub-2-mobile-datasheet.pdf
ICH3 Datasheet Chapter 6.4 and Table 6-5 https://www.intel.com/content/dam/doc/datasheet/82801ca-io-controller-hub-3-datasheet.pdf
ICH4 Datasheet Chapter 6.4 and Table 6-5 https://www.intel.com/content/dam/www/public/us/en/documents/datasheets/82801db-io-controller-hub-4-datasheet.pdf
ICH5 Datasheet Chapter 6.4 and Table 133 https://www.intel.com/content/dam/doc/datasheet/82801eb-82801er-io-controller-hub-datasheet.pdf
ICH6 Datasheet Chapter 6.4 and Table 6-4 https://www.intel.com/content/dam/doc/datasheet/io-controller-hub-6-datasheet.pdf
ICH7 Datasheet Chapter 6.4 and Table 6-4 https://www.intel.com/content/dam/doc/datasheet/i-o-controller-hub-7-datasheet.pdf
ICH8 Datasheet Chapter 6.4 and Table 102 https://www.intel.com/content/dam/www/public/us/en/documents/datasheets/io-controller-hub-8-datasheet.pdf
ICH9 Datasheet Chapter 9.4 and Table 9-4 https://www.intel.com/content/dam/doc/datasheet/io-controller-hub-9-datasheet.pdf
ICH10 Datasheet Chapter 9.4 and Table 9-4 https://theswissbay.ch/pdf/Datasheets/Intel/io-controller-hub-10-family-datasheet.pdf
PCH Intel 5 Series Datasheet Chapter 9.4 and Table 9-4 https://www.intel.com/content/dam/www/public/us/en/documents/datasheets/5-chipset-3400-chipset-datasheet.pdf
PCH Intel 6 Series Datasheet Chapter 9.4 and Table 9-4 https://www.intel.com/content/dam/www/public/us/en/documents/datasheets/6-chipset-c200-chipset-datasheet.pdf
PCH Intel 7 Series Datasheet Chapter 9.4 and Table 9-4 https://www.intel.com/content/dam/www/public/us/en/documents/datasheets/7-series-chipset-pch-datasheet.pdf
PCH Intel 8 Series Datasheet Chapter 9.4 and Table 9-4 https://www.intel.com/content/dam/www/public/us/en/documents/datasheets/8-series-chipset-pch-datasheet.pdf
PCH Intel 9 Series Datasheet Chapter 9.4 and Table 9-4 https://www.intel.com/content/dam/www/public/us/en/documents/datasheets/9-series-chipset-pch-datasheet.pdf
PCH Intel 100 Series Datasheet Vol 1 Chapter 4.3 and Table 4-4 https://www.intel.com/content/dam/www/public/us/en/documents/datasheets/100-series-chipset-datasheet-vol-1.pdf
PCH Intel 200 Series Datasheet Vol 1 Chapter 4.3 and Table 4-4 https://www.mouser.com/datasheet/2/612/200-series-chipset-pch-datasheet-vol-1-1391746.pdf
PCH Intel 300 Series Datasheet Vol 1 Chapter 4.3 and Table 4-4 https://www.intel.com/content/dam/www/public/us/en/documents/technical-specifications/300-series-chipset-on-package-pch-datasheet-vol-1.pdf
PCH Intel 400 Series Datasheet Vol 1 Chapter 4.2 and Table 8 https://images-eu.ssl-images-amazon.com/images/I/B1TDsSyARKS.pdf
Hans-Gert Dahmen
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