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

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Date:	Fri, 11 Dec 2015 12:08:05 -0800
From:	Andy Lutomirski <luto@...capital.net>
To:	Tony Luck <tony.luck@...el.com>
Cc:	Ingo Molnar <mingo@...nel.org>, Borislav Petkov <bp@...en8.de>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Andy Lutomirski <luto@...nel.org>,
	Dan Williams <dan.j.williams@...el.com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"linux-mm@...ck.org" <linux-mm@...ck.org>,
	linux-nvdimm <linux-nvdimm@...1.01.org>, X86 ML <x86@...nel.org>
Subject: Re: [PATCHV2 2/3] x86, ras: Extend machine check recovery code to
 annotated ring0 areas

On Thu, Dec 10, 2015 at 4:14 PM, Tony Luck <tony.luck@...el.com> 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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