Re: [PATCHV2 2/3] x86, ras: Extend machine check recovery code to annotated ring0 areas

From: Andy Lutomirski
Date: Fri Dec 11 2015 - 15:08:29 EST


On Thu, Dec 10, 2015 at 4:14 PM, Tony Luck <tony.luck@xxxxxxxxx> wrote:
> Extend the severity checking code to add a new context IN_KERN_RECOV
> which is used to indicate that the machine check was triggered by code
> in the kernel with a fixup entry.
>
> Add code to check for this situation and respond by altering the return
> IP to the fixup address and changing the regs->ax so that the recovery
> code knows the physical address of the error. Note that we also set bit
> 63 because 0x0 is a legal physical address.
>
> Major re-work to the tail code in do_machine_check() to make all this
> readable/maintainable. One functional change is that tolerant=3 no longer
> stops recovery actions. Revert to only skipping sending SIGBUS to the
> current process.

This is IMO much, much nicer than the old code. Thanks!

--Andy
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