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From: Frederic Weisbecker <fweisbec@gmail.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: LKML <linux-kernel@vger.kernel.org>, Ingo Molnar <mingo@elte.hu>,
	Arnaldo Carvalho de Melo <acme@redhat.com>,
	Paul Mackerras <paulus@samba.org>,
	Stephane Eranian <eranian@google.com>,
	Cyrill Gorcunov <gorcunov@openvz.org>,
	Tom Zanussi <tzanussi@gmail.com>,
	Masami Hiramatsu <mhiramat@redhat.com>,
	Steven Rostedt <rostedt@goodmis.org>,
	Robert Richter <robert.richter@amd.com>
Subject: Re: [RFC PATCH 1/9] uaccess: Make copy_from_user_nmi() globally available
Date: Wed, 13 Oct 2010 16:47:36 +0200	[thread overview]
Message-ID: <20101013144734.GB5335@nowhere> (raw)
In-Reply-To: <1286954156.29097.53.camel@twins>

On Wed, Oct 13, 2010 at 09:15:56AM +0200, Peter Zijlstra wrote:
> On Wed, 2010-10-13 at 07:06 +0200, Frederic Weisbecker wrote:
> > In order to support user stack dump safely in perf samples from
> > generic code, export copy_from_user_nmi() from x86 and make it
> > generally available. For most archs it will map to
> > copy_from_user_inatomic, but for x86 we need to take care of
> > not faulting from NMIs.
> > 
> > Since perf is the first user for now, let the overriden x86
> > implementation in the perf source file.
> 
> It might make sense to call it copy_from_user_gup() because that's
> bascially what it does, it doesn't rely on NMI context anymore, its just
> NMI-safe.
> 
> Its a best effort software page table walk, and with the stacked
> kmap_atomic bits Andrew took it should work from any context.


Ok, I'll do the rename. Does that work on any arch?

Thanks.


  reply	other threads:[~2010-10-13 14:47 UTC|newest]

Thread overview: 33+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-10-13  5:06 [RFC] perf: Dwarf cfi based user callchains Frederic Weisbecker
2010-10-13  5:06 ` [RFC PATCH 1/9] uaccess: Make copy_from_user_nmi() globally available Frederic Weisbecker
2010-10-13  7:15   ` Peter Zijlstra
2010-10-13 14:47     ` Frederic Weisbecker [this message]
2010-10-13 20:43       ` Peter Zijlstra
2010-10-13  5:06 ` [RFC PATCH 2/9] perf: Add ability to dump user regs Frederic Weisbecker
2010-10-13  7:20   ` Peter Zijlstra
2010-10-13 14:56     ` Frederic Weisbecker
2010-10-13 14:58     ` Frederic Weisbecker
2010-10-14 11:06     ` Stephane Eranian
2010-10-14 11:20       ` Frederic Weisbecker
2010-10-15  8:39         ` Stephane Eranian
2010-10-15 22:58           ` Frederic Weisbecker
2010-10-17 10:07             ` Peter Zijlstra
2010-10-18 10:01               ` Stephane Eranian
2010-10-18 22:35                 ` Frederic Weisbecker
2010-10-20  9:24                   ` Stephane Eranian
2010-10-20 16:13                     ` Frederic Weisbecker
2010-10-20 16:19                     ` Peter Zijlstra
2010-10-13  5:06 ` [RFC PATCH 3/9] perf: Add ability to dump part of the user stack Frederic Weisbecker
2010-10-13  7:22   ` Peter Zijlstra
2010-10-13 15:01     ` Frederic Weisbecker
2010-10-13  5:06 ` [RFC PATCH 4/9] perf: Don't record frame pointer based user stacktraces if we dump stack and regs Frederic Weisbecker
2010-10-13  7:23   ` Peter Zijlstra
2010-10-13 15:02     ` Frederic Weisbecker
2010-10-16  0:19     ` Frederic Weisbecker
2010-10-13  5:06 ` [RFC PATCH 5/9] perf: Support for dwarf mode callchain on perf record Frederic Weisbecker
2010-10-13  5:06 ` [RFC PATCH 6/9] perf: Build with dwarf cfi Frederic Weisbecker
2010-10-13  5:06 ` [RFC PATCH 7/9] perf: Support for error passed over pointers Frederic Weisbecker
2010-10-13  5:07 ` [RFC PATCH 8/9] perf: Add libunwind dependency for dwarf cfi unwinding Frederic Weisbecker
2010-10-13  5:07 ` [RFC PATCH 9/9] perf: Support for dwarf cfi unwinding on post processing Frederic Weisbecker
2010-10-13 15:13 ` [RFC] perf: Dwarf cfi based user callchains Frank Ch. Eigler
2010-10-20 15:35   ` Frederic Weisbecker

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