[RFC PATCH 2/7] x86/sci: add core implementation for system call isolation

[Peter Zijlstra]

On Tue, Apr 30, 2019 at 07:03:37AM +0200, Ingo Molnar wrote:
> So the question IMHO isn't whether it's "valid C", because we already 
> have the Linux kernel's own C syntax variant and are enforcing it with 
> varying degrees of success.

I'm not getting into the whole 'safe' fight here; but you're under
selling things. We don't have a C syntax, we have a full blown C
lanugeage variant.

The 'Kernel C' that we write is very much not 'ANSI/ISO C' anymore in a
fair number of places. And if I can get my way, we'll only diverge
further from the standard.

And this is quite separate from us using every GCC extention under the
sun; which of course also doesn't help. It mostly has to do with us
treating C as a portable assembler and the C people not wanting to
commit to sensible things because they think C is a high-level language.