Dumb question, but how would it fare on a ppc64le box like the (OpenPower) Power9 Talos II? https://www.raptorcs.com/TALOSII/prerelease.php
289 karma · joined November 24, 2014
My hunch says that chips affected by 4a could easily be fair game (4a is speculating reads into priviledged regs... I wonder if 4a would work on regs that are trapped, not inconceivable)
On Arm the conditional speculation barrier couldn’t be more lightweight (CSDB).
yes you could, but the noise floor won’t be great
TI-GCC for my TI-89 was nice...a few years back I tried to dust-off my IMSA-issued 89, and...it didn’t turn on. Sad. Replaced all batteries. Nothing... Then the flex connector on my 83+ started flaking out (the LCD corruption issue plaguing these...).
The biggest possible barrier to that today, which is still unknown, is the quality of the USB host controller. NICs use bulk, but there's no guarantee that the host controller driver is good enough. Time will tell, I suppose...
The specification doesn't say that an implementation must not change the memory map inside ExitBootServices, and in practice many runtime drivers clean up or even perform RT Data allocations in that path. This results in the "MapKey is incorrect" error returned to the caller. (I've seen some that modify ACPI and SMBIOS on the fly inside the ExitBootServices path, awful, awful, awful).
So yes, the program calling ExitBootServices must be written to retry the call even if it really did avoid sandwiching any calls to UEFI between the last GetMemoryMap and ExitBootServices.
The other big Achille's heel of UEFI in general is the SetVirtualAddressMap() RT call and RT Services support in general, but Tiano's driver model makes it particularly easy to shoot yourself in the face and end up with an implementation that forces the OS to call RT services with identity mappings or even with mappings for supposedly non-RT regions. Ugh. MMIO is a favorite one to "forget" to add to the memory map as an RT entry.
UEFI uses the PE format for binaries, but doesn't actually mandate how PE should be used or what the allowed relocations are. You could build a PE binary that amounted to, say, tons of executable segments, each of which will be a separate memory map entry. Now since UEFI doesn't mandate exactly how an OS will assign virtual addresses (for SetVirtualAddressMap), nor exposes relative grouping of memory descriptors (forcing the OS to relocate these keeping relative distances) I can imagine a situation where RT drivers could break if the OS decided to aggressively compact the address map or instead introduce random large VA gaps between RT memory map entries.
Note that these numbers will also include Arm Trusted Firmware and firmware tables.
If you wanted to run you own drivers, or had code written specifically against protocols exported by Tiano components I believe the answer is - yes.
RaspberryPiPkg is the $35 64-bit Arm UEFI devkit.
Of couse the U-boot implementation of UEFI spec is getting better and better day by day, and that’s obviously awesome. I am sure someone will add ACPI support to it any day now. Having choice is good, and I wouldn’t want to live in a world with a single implementation. That said, Tiano (like it or not) /is/ the reference implementation, and you’re much less likely to run into surprises (today). Notice how I didn’t say Tiano is /better/, because in a number of ways (code quality, complexity, fragmentation) it’s pretty awful.
One thing the U-boot implementation excels at is embedded Arm board support - U-boot is the defacto firmware for most embedded hardware, and now all of that hardware is EFI-capable. Porting Tiano is effort you don’t want to spend.
That said, there are hybrid approaches - EFIDroid (efidroid.org) runs Tiano on top of LK, using LK’s platform support for drivers.
As a random person stumbling upon this, what value would you assign to it? What could you imagine the end goal to be?
It’s been useful to be able to run the same Ubuntu and SUSE images as VMs and servers do, but that’s only really possible because the built kernels have RPi3 support (but at least you now don’t need a custom image with U-Boot).
If you don’t want feedback, don’t ask for feedback by posting publicly. My “rant” is a collection of issues I’ve seen for at least the last 7 years of actively paying attention to the project.
To reach any mass of users (outside of turnkey solutions where the end users may not know or care), you need commercial support and the later needs concrete identified market segments. To parallel Wine - ROS needs its own CrossOver (but not Cedega).
If you install 7Zip, you should know that 7Zip does not associate itself with file extensions by default. This is 7zip behavior. You need to run 7zip, go to options, and set associations by clicking on the '+' button.