'"AMD and Intel have both proposed better ways of doing interrupt and
exception handling the last few months," reports LinuxReviews.org
Then they share this analysis Linus Torvalds posted on the Real World
"The AMD version is essentially "Fix known bugs in the exception
The Intel version is basically "Yeah, the protected mode 80286
exception handling was bad, then 386 made it odder with the 32-bit
extensions, and then syscall/sysenter made everything worse, and then
the x86-64 extensions introduced even more problems. So let's add a
mode bit where all the crap goes away".
In contrast, the AMD one is basically a minimal effort to fix actual
fundamental problems with all that legacy-induced crap that are nasty
to work around and that have caused issues...
Both are valid on their own, and they are actually fairly independent.
Honestly, the AMD paper looks like a quick "we haven't even finished
thinking all the details through, but we know these parts were broken,
so we might as well release this".
I don't know how long it has been brewing, but judging by the "TBD"
things in that paper, I think it's a "early rough draft"."
In the article (shared by long-time Slashdot reader xiando),
summarizes the state of the conversation today:
Torvalds went on to say that while AMD's proposed "quick fix" would be
easier to implement for him and others operating system vendors, it's
not ideal in the long run. Intel's proposal throws the entire existing
interrupt descriptor table (IDT) delivery system under the bus so it
can be replaced with what they call a new "FRED event delivery"
system. Torvalds believes this is a better long-term solution...
While the pros and cons of Intel and AMD's respective proposals for
interrupt and event handling in future processors are worthy of
discussion, it's in reality mostly up to Intel. They are the bigger
and more powerful corporation. It is more likely than not that future
processors from Intel will use their proposed Flexible Return and
Event Delivery system. Their next generation processors won't, it will
take years not months before consumer CPUs have the FRED technology.
Remember, the above-mentioned technical document was published earlier
this month [in March]. Things do not magically go from the
drawing-board to store-shelves overnight.
Intel isn't going to just hand the FRED technology over to AMD and
help them implement it. We will likely see both move forward with
their own proposals. Intel will have FRED and AMD will have Supervisor
Entry Extensions until AMD, inevitably, adopts FRED or some form of it
years down the line.
They also note that Torvalds took issue with a poster arguing that
microkernels are more secure than monolithic kernels like Linux.
"Bah, you're just parroting the usual party line that had absolutely
no basis in reality and when you look into the details, doesn't
actually hold up.
It's all theory and handwaving and just repeating the same old FUD
that was never actually really relevant."'
-- source: https://hardware.slashdot.org/story/21/04/03/179214
Dept. of Computer Science
University of Waikato, NZ
+64 (7) 577-5304