linux-kernel - RE: [PATCH] RAS: Add a tracepoint for reporting memory controller events

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <3908561D78D1C84285E8C5FCA982C28F192F6C61@ORSMSX104.amr.corp.intel.com>
Date:	Thu, 31 May 2012 16:51:27 +0000
From:	"Luck, Tony" <tony.luck@...el.com>
To:	Borislav Petkov <bp@...64.org>
CC:	Mauro Carvalho Chehab <mchehab@...hat.com>,
	Linux Edac Mailing List <linux-edac@...r.kernel.org>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	Aristeu Rozanski <arozansk@...hat.com>,
	Doug Thompson <norsk5@...oo.com>,
	Steven Rostedt <rostedt@...dmis.org>,
	Frederic Weisbecker <fweisbec@...il.com>,
	Ingo Molnar <mingo@...hat.com>
Subject: RE: [PATCH] RAS: Add a tracepoint for reporting memory controller
 events

>>                         u8 shift = MCI_MISC_ADDR_LSB(m->misc);
>>                         m->addr >>= shift;
>>                         m->addr <<= shift;
>
> That's 64 bytes max, IIRC.

No, it's a 6-bit field used as a shift ... so if it has value "6", it means
cache line granularity. Value "12" would mean 4K granularity. Architecturally
it could say "30" to mean gigabyte, or even "63" to mean "everything is gone".

>> while a few (IIRC patrol scrub) will report with page (4K)
>> granularity. Linux doesn't really care - they all have to get rounded
>> up to page size because we can't take away just one cache line from a
>> process.
>
> I'd like to see that :-)

Patrol scrub works inside the depths of the memory controller on rank/row
addresses, not on system physical addresses. When it finds a problem, a
reverse translation is needed to be able to report a system physical
address in MCi_ADDR. Getting all the bits right is apparently a hard thing
to do, so the MCI_MISC_ADDR_LSB bits are used to indicate that some low
order bits are not valid.

-Tony
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/