From: Peter Zijlstra <peterz@infradead.org>
To: Frederic Weisbecker <fweisbec@gmail.com>
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 09:15:56 +0200 [thread overview]
Message-ID: <1286954156.29097.53.camel@twins> (raw)
In-Reply-To: <1286946421-32202-2-git-send-regression-fweisbec@gmail.com>
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.
next prev parent reply other threads:[~2010-10-13 7:16 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 [this message]
2010-10-13 14:47 ` Frederic Weisbecker
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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