linux-kernel - Re: [RFC PATCH 3/3] objtool/mcount: Add powerpc specific functions

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: <0b55f122-4760-c1ba-840a-0911cefec2ad@csgroup.eu>
Date:   Sun, 27 Mar 2022 09:09:20 +0000
From:   Christophe Leroy <christophe.leroy@...roup.eu>
To:     Peter Zijlstra <peterz@...radead.org>,
        "jpoimboe@...hat.com" <jpoimboe@...hat.com>
CC:     "aik@...abs.ru" <aik@...abs.ru>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "rostedt@...dmis.org" <rostedt@...dmis.org>,
        "naveen.n.rao@...ux.vnet.ibm.com" <naveen.n.rao@...ux.vnet.ibm.com>,
        "linuxppc-dev@...ts.ozlabs.org" <linuxppc-dev@...ts.ozlabs.org>,
        Sathvika Vasireddy <sv@...ux.ibm.com>
Subject: Re: [RFC PATCH 3/3] objtool/mcount: Add powerpc specific functions

Hi Peter, Hi Josh

Le 18/03/2022 à 13:26, Peter Zijlstra a écrit :
> On Fri, Mar 18, 2022 at 04:21:40PM +0530, Sathvika Vasireddy wrote:
>> This patch adds powerpc specific functions required for
>> 'objtool mcount' to work, and enables mcount for ppc.
> 
> I would love to see more objtool enablement for Power :-)
> 
> 

I'm also very happy someone started to look at it.

I thought it would be more difficult to get it work on powerpc.

Iml looking forward to being able to use it and implement INLINE STATIC 
CALLs on PPC32 to start with.

I'm wondering what are the plans on your side and what we should wait 
for and what we could start with.

I could do the same as done by Sathvika for static calls, in extenso get 
it out of check.c into a standalone feature. On the other hand I 
understood that Josh is also working at making the different features of 
objtool independant, so should I wait for that ? Any idea of when it 
comes out ?

Second point is the endianess and 32/64 selection, especially when 
crossbuilding. There is already some stuff regarding endianess based on 
bswap_if_needed() but that's based on constant selection at build time 
and I couldn't find an easy way to set it conditionaly based on the 
target being built.

Regarding 32/64 selection, there is almost nothing, it's based on using 
type 'long' which means that at the time being the target and the build 
platform must both be 32 bits or 64 bits.

For both cases (endianess and 32/64) I think the solution should 
probably be to start with the fileformat of the object file being 
reworked by objtool.

What are current works in progress on objtool ? Should I wait Josh's 
changes before starting looking at all this ? Should I wait for anything 
else ?

Christophe