From: malc <av1474@comtv.ru>
To: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: linuxppc-dev@lists.ozlabs.org, hollis@penguinppc.org
Subject: Re: Probing for native availability of isel from userspace
Date: Sun, 23 Sep 2012 00:17:24 +0400 (MSK) [thread overview]
Message-ID: <alpine.LNX.2.00.1209230016180.6262@linmac> (raw)
In-Reply-To: <1348343737.1132.74.camel@pasglop>
On Sun, 23 Sep 2012, Benjamin Herrenschmidt wrote:
> On Sat, 2012-09-22 at 21:08 +0200, Segher Boessenkool wrote:
> > > Thanks for suggestion, but i'd rather not play with heuristics.
> >
> > Have a look at /sys/kernel/debug/powerpc/emulated_instructions/ then?
>
> Userspace should *NEVER* rely on the content of debugfs, it will change
> with time, it is not a guaranteed ABI, it's purely for people to look
> at... for debugging.
Furthermore this box simply doesn't have it built-in...
>
> Unfortunately we don't expose ISEL support via features (maybe we
> should, this is reasonably easy to fix, except that we are running short
> on feature bits and adding a new set of bits isn't totally trivial).
>
> At this stage I would recommend using arch 2.06 as your key/trigger and
> either add a handful of known PVR values (mfpvr is emulated) for other
> CPUs you know support it (there shouldn't be that many), or just do the
> heuristic :-(
>
Thank you.
--
mailto:av1474@comtv.ru
next prev parent reply other threads:[~2012-09-22 20:17 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-09-21 20:05 Probing for native availability of isel from userspace malc
2012-09-22 7:26 ` Segher Boessenkool
2012-09-22 10:12 ` malc
2012-09-22 10:21 ` Gabriel Paubert
2012-09-22 15:37 ` malc
2012-09-22 16:13 ` David Gibson
2012-09-22 19:08 ` Segher Boessenkool
2012-09-22 19:55 ` Benjamin Herrenschmidt
2012-09-22 20:17 ` malc [this message]
2012-09-23 1:46 ` Segher Boessenkool
2012-09-24 7:55 ` Gabriel Paubert
2012-09-24 7:58 ` Benjamin Herrenschmidt
2012-09-24 8:06 ` Gabriel Paubert
2012-09-24 9:41 ` Benjamin Herrenschmidt
2012-09-25 13:17 ` Segher Boessenkool
2012-09-25 20:59 ` Benjamin Herrenschmidt
2012-09-26 0:17 ` Kumar Gala
2012-09-24 23:55 ` Scott Wood
2012-09-25 0:32 ` Benjamin Herrenschmidt
2012-09-25 0:40 ` Scott Wood
2012-09-25 0:47 ` malc
2012-09-25 0:50 ` Scott Wood
2012-09-25 13:31 ` Segher Boessenkool
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