From: Andy Lutomirski <luto@amacapital.net>
To: Tony Luck <tony.luck@gmail.com>
Cc: Borislav Petkov <bp@alien8.de>,
linux-nvdimm <linux-nvdimm@ml01.01.org>, X86 ML <x86@kernel.org>,
"elliott@hpe.com" <elliott@hpe.com>,
"linux-mm@kvack.org" <linux-mm@kvack.org>,
Andrew Morton <akpm@linux-foundation.org>,
"Williams, Dan J" <dan.j.williams@intel.com>,
Ingo Molnar <mingo@kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCHV5 3/3] x86, ras: Add __mcsafe_copy() function to recover from machine checks
Date: Sun, 27 Dec 2015 04:18:42 -0800 [thread overview]
Message-ID: <CALCETrV2g6vSQcpNUADWeLMj5O_HDEGgp6vvLw9KgJVTWxZ1+g@mail.gmail.com> (raw)
In-Reply-To: <CA+8MBbJcw8dRW3DBYW-EhcOiGYFCm7HUxwG-df67wJCOqMpz0A@mail.gmail.com>
On Sat, Dec 26, 2015 at 10:57 PM, Tony Luck <tony.luck@gmail.com> wrote:
> On Sat, Dec 26, 2015 at 6:16 PM, Andy Lutomirski <luto@amacapital.net> wrote:
>>>> We could make one of them 31-bits (since even an "allyesconfig" kernel
>>>> is still much smaller than a gigabyte) to free a bit for a flag. But there
>>>> are those external tools to pre-sort exception tables that would all
>>>> need to be fixed too.
>>
>> Wait, why? The external tools sort by source address, and we'd
>> squeeze the flag into the target address, no?
>
> I was thinking that we'd need to recompute the fixup when we move
> the entry to its new sorted location. So that:
>
> ex_fixup_addr(const struct exception_table_entry *x)
> {
> return (unsigned long)&x->fixup + x->fixup;
> }
>
> will get the right value. Maybe this would still work out
> if the fixup is a 31-bit value plus a flag, but the external
> tool thinks it is a 32-bit value? I'd have to ponder that.
I think I can save you some pondering. This old patch gives two flag
bits. Feel free to borrow the patch, but you'll probably want to
change the _EXTABLE_CLASS_XYZ macros:
https://git.kernel.org/cgit/linux/kernel/git/luto/linux.git/commit/?h=strict_uaccess_fixups/patch_v1&id=16644d9460fc6531456cf510d5efc57f89e5cd34
--Andy
next prev parent reply other threads:[~2015-12-27 12:19 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-12-24 20:54 [PATCHV4 0/3] Machine check recovery when kernel accesses poison Tony Luck
2015-12-16 1:29 ` [PATCHV4 1/3] x86, ras: Add new infrastructure for machine check fixup tables Tony Luck
2015-12-16 1:29 ` [PATCHV4 2/3] x86, ras: Extend machine check recovery code to annotated ring0 areas Tony Luck
2015-12-16 1:30 ` [PATCHV4 3/3] x86, ras: Add __mcsafe_copy() function to recover from machine checks Tony Luck
2015-12-24 21:46 ` Borislav Petkov
2015-12-16 1:30 ` [PATCHV5 " Tony Luck
2015-12-25 11:49 ` Borislav Petkov
2015-12-25 20:05 ` Luck, Tony
2015-12-26 10:32 ` Borislav Petkov
2015-12-26 14:54 ` Andy Lutomirski
2015-12-27 2:08 ` Tony Luck
2015-12-27 2:15 ` Andy Lutomirski
2015-12-27 2:16 ` Andy Lutomirski
2015-12-27 6:57 ` Tony Luck
2015-12-27 10:09 ` Borislav Petkov
2015-12-27 12:19 ` Andy Lutomirski
2015-12-27 13:17 ` Boris Petkov
2015-12-27 13:25 ` Andy Lutomirski
2015-12-27 13:33 ` Borislav Petkov
2015-12-27 13:40 ` Andy Lutomirski
2015-12-27 19:04 ` Dan Williams
2015-12-27 12:18 ` Andy Lutomirski [this message]
2015-12-30 23:32 ` Tony Luck
2015-12-31 20:30 ` Tony Luck
2015-12-31 21:22 ` Andy Lutomirski
2016-01-01 22:19 ` Tony Luck
2016-01-03 3:40 ` Andy Lutomirski
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