1 Jan
2023
1 Jan
'23
3:10 a.m.
On Sat, Dec 31, 2022 at 2:08 PM Clem Cole <clemc(a)ccc.com> wrote:
Perhaps this is what it is, but I think taking a step back and looking
at the problem more generally, it's because they're mutated into
solving the wrong problem. Consider AML: isn't this something that
ought to be handled in, I don't know, a device driver? Yes, that
driver may need access to some platform-specific firmware to abstract
the details, but an entire virtual machine running random code to
provide abstractions for the firmware writers who are running,
basically, a parallel operating systems is a bit on the nose. This
goes way beyond OpenBoot's forth modules on option ROMs (which were
kind of a nifty idea for device discovery and such things).
Mothy Roscoe gave a really interesting keynote at OSDI'21:
https://www.youtube.com/watch?v=36myc8wQhLo
I love how he describes the interfaces we have now as having
"congealed." But in some ways, UEFI+ACPI are the antithesis of what
the OS should be doing.
- Dan C.
On Sat, Dec 31, 2022 at 10:02 AM Dan Cross
<crossd(a)gmail.com> wrote:
I'm going to push back on this slightly: UEFI+ACPI get a bad rap
because, well, they're really pretty bad. Oh sure, some things are
reasonable: the ACPI table formats aren't awful. But I've been inside
a couple of these now and phew golly, they stink pretty badly. The
code is poor quality, and encourages running blobs of really dubious
provenance. See below....
[snip]
SBI was/is an attempt to define a common interface to different
devices using RISC-V CPUs, but it's growing wildly and tending more
towards UEFI+ACPI than something like OpenBoot, which was much
simpler.
UEFI+ACPI got/gets a bad rep because of the original IBM BIOS implementations. In general,
the idea of a BIOS isn't terrible: provide an interface
that decouples the OS and hardware.
Exactly - the idea is actually a good one. But the problem was the BIOS
designed/implemented by HW people, but OS folks. Things like concurrency minimum use of
the CPU was not in the higher order bits.
But in practice, no one has come
up with a particularly good set of interfaces yet. Ironically,
BSD-style autoconfig might have been the best yet.
??Maybe because it was OS types who knew what the OS needed to discover/report/deliver
back from the HW.