Re: [RFC/INCOMPLETE 08/13] x86/entry/64: Migrate 64-bit syscalls to new exit hooks

[Ingo Molnar]

* Andy Lutomirski <luto@xxxxxxxxxxxxxx> wrote:

> >> Any reason why irq state tracking cannot be done in C as well, like the rest 
> >> of the irq state tracking code?
> >
> > Never mind, I see you've done exactly that in patch #12.
> 
> There are still some TRACE_IRQS_ON, LOCKDEP_SYS_EXIT, and such scattered 
> throughout the asm.  it's plausible that even more of that could be moved to C.
> 
> We could also benchmark and find out how bad it would be if we just always 
> filled pt_regs in completely in syscalls.  If the performance hit isn't enough 
> to matter, then we could potentially move the entire syscall path except pt_regs 
> setup and sysret/iret into three C functions.

The thing is, I'd not be against simplifying pt_regs handling even if it slows 
down things a tiny bit. If anyone wants to reintroduce that complexity we'll see 
how it looks like in isolation, done cleanly.

Thanks,

	Ingo
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