linux-kernel - Re: [PATCH 01/12] powerpc/module: Only try to generate the ftrace

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Date:	Thu, 25 Feb 2016 20:08:04 +0530
From:	Kamalesh Babulal <kamalesh@...ux.vnet.ibm.com>
To:	Michael Ellerman <mpe@...erman.id.au>
Cc:	linuxppc-dev@...abs.org, bsingharora@...il.com, duwe@....de,
	linux-kernel@...r.kernel.org, rostedt@...dmis.org,
	pmladek@...e.com, jeyu@...hat.com, jkosina@...e.cz,
	live-patching@...r.kernel.org, mbenes@...e.cz
Subject: Re: [PATCH 01/12] powerpc/module: Only try to generate the
 ftrace_caller() stub once

* Michael Ellerman <mpe@...erman.id.au> [2016-02-25 01:28:24]:

> Currently we generate the module stub for ftrace_caller() at the bottom
> of apply_relocate_add(). However apply_relocate_add() is potentially
> called more than once per module, which means we will try to generate
> the ftrace_caller() stub multiple times.
> 
> Although the current code deals with that correctly, ie. it only
> generates a stub the first time, it would be clearer to only try to
> generate the stub once.
> 
> Note also on first reading it may appear that we generate a different
> stub for each section that requires relocation, but that is not the
> case. The code in stub_for_addr() that searches for an existing stub
> uses sechdrs[me->arch.stubs_section], ie. the single stub section for
> this module.
> 
> A cleaner approach is to only generate the ftrace_caller() stub once,
> from module_finalize(). An additional benefit is we can clean the ifdefs
> up a little.
> 
> Finally we must propagate the const'ness of some of the pointers passed
> to module_finalize(), but that is also an improvement.
> 
> Signed-off-by: Michael Ellerman <mpe@...erman.id.au>

For all of the patches in the series.

Tested-by: Kamalesh Babulal <kamalesh@...ux.vnet.ibm.com>


Regards,
Kamalesh.