Re: [PATCH] s390/perf: fix 'start' address of module's map

From: Arnaldo Carvalho de Melo
Date: Wed Jul 27 2016 - 09:06:02 EST

Em Wed, Jul 27, 2016 at 07:24:26PM +1000, Michael Ellerman escreveu:
> Arnaldo Carvalho de Melo <acme@xxxxxxxxxx> writes:
> > Em Tue, Jul 26, 2016 at 10:14:18PM +0200, Christian Borntraeger escreveu:
> >> On 07/26/2016 09:50 PM, Arnaldo Carvalho de Melo wrote:
> >> > So I could as well use what is in /sys/module/tun/sections/.text instead
> >> > of reading it from /proc/modules and, in s390, reading it from
> >> > /sys/module/tun/sections/.text.

> >> > Do you see any problem with using this approach for _all_ arches?

> >> I think it should work well for _all_ arches but it will probably be
> >> hard to test this without help.

> > Well, we could check for the cases we don't know, i.e. read from both
> > and warn about cases where it is different, except for s390 where we now
> > which is the right one to pick.

> >> I wouldn't be surprised if other architectures than s390 actually have
> >> the same issue, so doing this for everybody might atually fix this somewhere
> >> else.

> > Would be nice to get info from other arch people, Michael, how this goes
> > on ppc?

> It doesn't look like this is a problem on powerpc - at least I haven't
> heard of it.

> Looking at a system I have here, for all modules (26) the value in
> /proc/modules matches the .text section in /sys.

> So I think using /sys should be fine for us.

Thanks for checking.

- Arnaldo