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From: Martin Schwidefsky <schwidefsky@de.ibm.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Andy Lutomirski <luto@amacapital.net>,
	Valdis Kletnieks <Valdis.Kletnieks@vt.edu>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	Paul Mackerras <paulus@samba.org>,
	Arnaldo Carvalho de Melo <acme@kernel.org>,
	Ingo Molnar <mingo@redhat.com>, Kees Cook <keescook@chromium.org>,
	Andrea Arcangeli <aarcange@redhat.com>,
	Erik Bosman <ebn310@few.vu.nl>,
	mpe@ellerman.id.au, anton@samba.org,
	brueckner@linux.vnet.ibm.com
Subject: Re: [RFC 5/5] x86,perf: Only allow rdpmc if a perf_event is mapped
Date: Mon, 20 Oct 2014 11:24:13 +0200	[thread overview]
Message-ID: <20141020112413.56450095@mschwide> (raw)
In-Reply-To: <20141020084813.GB3219@twins.programming.kicks-ass.net>

On Mon, 20 Oct 2014 10:48:13 +0200
Peter Zijlstra <peterz@infradead.org> wrote:

> >  - cpumsf_pmu_event_idx is the same as power_pmu_event_idx.
> 
> Oh cute, lets ask the s390 people, do you guys have a userspace
> instruction to read the actual counter value?

The "extract cpu counter" ECCTR instruction can be authorized to
be used in user-space with a bit in CR0. With the current code
this bit is not set, the cpu measurement facility is not usable
in user space without a patch to the kernel.

-- 
blue skies,
   Martin.

"Reality continues to ruin my life." - Calvin.


  reply	other threads:[~2014-10-20  9:24 UTC|newest]

Thread overview: 47+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-10-14 22:57 [RFC 0/5] CR4 handling improvements Andy Lutomirski
2014-10-14 22:57 ` [RFC 1/5] x86: Clean up cr4 manipulation Andy Lutomirski
2014-10-16  8:16   ` Peter Zijlstra
2014-10-16 11:18     ` Borislav Petkov
2014-10-16 11:29       ` Borislav Petkov
2014-10-16 15:32         ` Andy Lutomirski
2014-10-16 15:47           ` Borislav Petkov
2014-10-14 22:57 ` [RFC 2/5] x86: Store a per-cpu shadow copy of CR4 Andy Lutomirski
2014-10-16  8:26   ` Peter Zijlstra
2014-10-16 11:49   ` Borislav Petkov
2014-10-16 15:30     ` Andy Lutomirski
2014-10-14 22:57 ` [RFC 3/5] x86: Add a comment clarifying LDT context switching Andy Lutomirski
2014-10-16 15:49   ` Borislav Petkov
2014-10-16 16:21     ` Andy Lutomirski
2014-10-21  5:41       ` Borislav Petkov
2014-10-21  5:44         ` Andy Lutomirski
2014-10-21  6:05           ` Borislav Petkov
2014-10-14 22:57 ` [RFC 4/5] perf: Add pmu callbacks to track event mapping and unmapping Andy Lutomirski
2014-10-14 22:57 ` [RFC 5/5] x86,perf: Only allow rdpmc if a perf_event is mapped Andy Lutomirski
2014-10-16  8:42   ` Peter Zijlstra
2014-10-16 15:37     ` Andy Lutomirski
2014-10-16 15:57     ` Borislav Petkov
2014-10-17  0:00   ` Andy Lutomirski
2014-10-19 20:23     ` Andy Lutomirski
2014-10-19 21:33       ` Peter Zijlstra
2014-10-19 22:05         ` Andy Lutomirski
2014-10-19 22:20           ` Peter Zijlstra
2014-10-19 22:57             ` Andy Lutomirski
2014-10-20  8:33               ` Peter Zijlstra
2014-10-20 16:49                 ` Andy Lutomirski
2014-10-20 17:39                   ` Andy Lutomirski
2014-10-21  8:59                     ` Peter Zijlstra
2014-10-19 21:35     ` Peter Zijlstra
2014-10-20  0:08       ` Andy Lutomirski
2014-10-20  8:48         ` Peter Zijlstra
2014-10-20  9:24           ` Martin Schwidefsky [this message]
2014-10-20 10:51           ` Hendrik Brueckner
2014-10-21  9:14             ` Peter Zijlstra
2014-10-21 15:52               ` Andy Lutomirski
2014-10-21  4:06 ` [RFC 0/5] CR4 handling improvements Vince Weaver
2014-10-21  4:28   ` Andy Lutomirski
2014-10-21 15:00     ` Vince Weaver
2014-10-21 16:04       ` Peter Zijlstra
2014-10-21 17:05         ` Vince Weaver
2014-10-23 11:42           ` Peter Zijlstra
2014-10-24 12:41             ` Vince Weaver
2014-10-24 22:14               ` Andy Lutomirski

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