Messages in this thread | | | From | Andy Lutomirski <> | Date | Mon, 17 Nov 2014 12:05:59 -0800 | Subject | Re: [RFC PATCH] x86, entry: Switch stacks on a paranoid entry from userspace |
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On Mon, Nov 17, 2014 at 12:03 PM, Borislav Petkov <bp@alien8.de> wrote: > On Mon, Nov 17, 2014 at 11:57:22AM -0800, Andy Lutomirski wrote: >> Would it be worth making a decision on task_work_add vs. stack >> switching first? > > Probably a prudent thing to do in order to save unnecessary cycles :-) > >> Stack switching pros: all this lockless allocation stuff is completely >> unnecessary, and it's plausible that the stack switching code will be >> added anyway. > > Yes. > > However, I'd like to be very sure this thing doesn't introduce any > regressions to the MCA code. So even if Tony's testing passes, I'd like > to be very conservative here and stress it more than usual. Because once > this thing hits upstream and stuff starts breaking, it'll be a serious > PITA reverting it. > > I hope you can understand my concerns.
I agree completely.
> > Btw, which branch has your latest version - I'd like to take a look at > it in detail.
https://git.kernel.org/cgit/linux/kernel/git/luto/linux.git/log/?h=x86/paranoid
I'm not quite ready to send v3. I want to do two things first:
1. Consider disabling the stack switch for double_fault.
2. Clean up the macros. I'll validate this by ensuring that the generated code is identical to the current version.
IOW, I don't expect the asm for machine_check to change.
--Andy
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