From: Pawel Moll <pawel.moll@arm.com>
Date: Fri, 13 Jun 2014 15:03:32 +0000 (+0100)
Subject: perf: Handle compat ioctl
X-Git-Tag: v3.2.65~2
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=b955a6aa610cc33e208129b3991deaf624b09594;p=pandora-kernel.git

perf: Handle compat ioctl

commit b3f207855f57b9c8f43a547a801340bb5cbc59e5 upstream.

When running a 32-bit userspace on a 64-bit kernel (eg. i386
application on x86_64 kernel or 32-bit arm userspace on arm64
kernel) some of the perf ioctls must be treated with special
care, as they have a pointer size encoded in the command.

For example, PERF_EVENT_IOC_ID in 32-bit world will be encoded
as 0x80042407, but 64-bit kernel will expect 0x80082407. In
result the ioctl will fail returning -ENOTTY.

This patch solves the problem by adding code fixing up the
size as compat_ioctl file operation.

Reported-by: Drew Richardson <drew.richardson@arm.com>
Signed-off-by: Pawel Moll <pawel.moll@arm.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/r/1402671812-9078-1-git-send-email-pawel.moll@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: David Ahern <dsahern@gmail.com>
[lizf: Backported to 3.4 by David Ahern]
Signed-off-by: Zefan Li <lizefan@huawei.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---

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