From: Torsten Duwe <duwe@lst.de>
To: Balbir Singh <bsingharora@gmail.com>
Cc: linuxppc-dev@ozlabs.org, linux-kernel@vger.kernel.org,
rostedt@goodmis.org, kamalesh@linux.vnet.ibm.com,
pmladek@suse.com, jeyu@redhat.com, jkosina@suse.cz,
live-patching@vger.kernel.org, mbenes@suse.cz
Subject: Re: [PATCH][v6][RFC] livepatch/ppc: Enable livepatching on powerpc
Date: Thu, 17 Mar 2016 16:42:56 +0100 [thread overview]
Message-ID: <20160317154256.GA32575@lst.de> (raw)
In-Reply-To: <1457506780-19556-1-git-send-email-bsingharora@gmail.com>
On Wed, Mar 09, 2016 at 05:59:40PM +1100, Balbir Singh wrote:
>
> Changelog v6:
> 1. Experimental changes -- need loads of testing
> Based on the assumption that very far TOC and LR values
> indicate the call happened through a stub and the
> stub return works differently from a local call which
> uses klp_return_helper.
Well, this is true, but the inverse is not.
Less than 2GiB between LR and TOC is a necessary but not a sufficient
condition for a local call.
I see the problem with your code that it hardly detects calls from one module
to another nearby. It will fail iff you mistake a global call to a module loaded
earlier to be local while patching AND you access global data / 64-bit constants
after that call before the TOC is sanitised again.
Torsten
prev parent reply other threads:[~2016-03-17 15:43 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-03-09 6:59 [PATCH][v6][RFC] livepatch/ppc: Enable livepatching on powerpc Balbir Singh
2016-03-09 9:19 ` Torsten Duwe
2016-03-09 9:44 ` Petr Mladek
2016-03-09 10:03 ` Torsten Duwe
2016-03-09 10:13 ` Jiri Kosina
2016-03-09 11:16 ` Torsten Duwe
2016-03-09 12:56 ` Petr Mladek
2016-03-09 10:27 ` Michael Ellerman
2016-03-10 0:40 ` Balbir Singh
2016-03-15 10:25 ` Miroslav Benes
2016-03-17 15:42 ` Torsten Duwe [this message]
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