From: Andy Lutomirski <luto@amacapital.net>
To: Tony Luck <tony.luck@intel.com>
Cc: Ingo Molnar <mingo@kernel.org>, Borislav Petkov <bp@alien8.de>,
Andrew Morton <akpm@linux-foundation.org>,
Andy Lutomirski <luto@kernel.org>,
Dan Williams <dan.j.williams@intel.com>, Robert <elliott@hpe.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linux-mm@kvack.org" <linux-mm@kvack.org>,
linux-nvdimm <linux-nvdimm@ml01.01.org>, X86 ML <x86@kernel.org>
Subject: Re: [PATCH v8 1/3] x86: Expand exception table to allow new handling options
Date: Fri, 8 Jan 2016 17:52:54 -0800 [thread overview]
Message-ID: <CALCETrURssJHn42dXsEJbJbr=VGPnV1U_-UkYEZ48SPUSbUDww@mail.gmail.com> (raw)
In-Reply-To: <3a259f1cce4a3c309c2f81df715f8c2c9bb80015.1452297867.git.tony.luck@intel.com>
On Fri, Jan 8, 2016 at 12:49 PM, Tony Luck <tony.luck@intel.com> wrote:
> Huge amounts of help from Andy Lutomirski and Borislav Petkov to
> produce this. Andy provided the inspiration to add classes to the
> exception table with a clever bit-squeezing trick, Boris pointed
> out how much cleaner it would all be if we just had a new field.
>
> Linus Torvalds blessed the expansion with:
> I'd rather not be clever in order to save just a tiny amount of space
> in the exception table, which isn't really criticial for anybody.
>
> The third field is a simple integer indexing into an array of handler
> functions (I thought it couldn't be a relative pointer like the other
> fields because a module may have its ex_table loaded more than 2GB away
> from the handler function - but that may not be actually true. But the
> integer is pretty flexible, we are only really using low two bits now).
>
> We start out with three handlers:
>
> 0: Legacy - just jumps the to fixup IP
> 1: Fault - provide the trap number in %ax to the fixup code
> 2: Cleaned up legacy for the uaccess error hack
I think I preferred the relative function pointer approach.
Also, I think it would be nicer if the machine check code would invoke
the handler regardless of which handler (or class) is selected. Then
the handlers that don't want to handle #MC can just reject them.
Also, can you make the handlers return bool instead of int?
--Andy
next prev parent reply other threads:[~2016-01-09 1:53 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-01-09 0:04 [PATCH v8 0/3] Machine check recovery when kernel accesses poison Tony Luck
2015-12-31 19:40 ` [PATCH v8 2/3] x86, mce: Check for faults tagged in EXTABLE_CLASS_FAULT exception table entries Tony Luck
2016-01-08 20:49 ` [PATCH v8 1/3] x86: Expand exception table to allow new handling options Tony Luck
2016-01-09 1:52 ` Andy Lutomirski [this message]
2016-01-09 3:39 ` Brian Gerst
2016-01-09 4:31 ` Brian Gerst
2016-01-09 6:36 ` Andy Lutomirski
2016-01-11 23:09 ` Brian Gerst
2016-01-11 23:22 ` Andy Lutomirski
2016-01-11 23:48 ` Luck, Tony
2016-01-09 17:45 ` Tony Luck
2016-01-09 18:00 ` Andy Lutomirski
2016-01-09 19:51 ` Tony Luck
2016-01-09 22:32 ` Andy Lutomirski
2016-01-10 1:15 ` Tony Luck
2016-01-11 0:25 ` Luck, Tony
2016-01-08 21:18 ` [PATCH v8 3/3] x86, mce: Add __mcsafe_copy() Tony Luck
2016-01-09 1:49 ` Andy Lutomirski
2016-01-09 17:48 ` Tony Luck
2016-01-09 17:57 ` Andy Lutomirski
2016-01-09 19:39 ` Tony Luck
2016-01-09 22:15 ` Dan Williams
2016-01-09 22:33 ` Andy Lutomirski
2016-01-10 0:23 ` Dan Williams
2016-01-10 1:40 ` Tony Luck
2016-01-10 11:26 ` Borislav Petkov
2016-01-11 10:44 ` Ingo Molnar
2016-01-13 23:22 ` Tony Luck
2016-01-14 4:39 ` Borislav Petkov
2016-01-30 0:35 ` Tony Luck
2016-01-30 10:28 ` Borislav Petkov
2016-02-01 23:10 ` Tony Luck
2016-02-01 23:16 ` Dan Williams
2016-01-12 0:26 ` Luck, Tony
2016-01-12 0:30 ` Andy Lutomirski
2016-01-12 0:37 ` Andy Lutomirski
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