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From: Jiri Olsa <jolsa@redhat.com>
To: Madhavan Srinivasan <maddy@linux.vnet.ibm.com>
Cc: linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
	Yury Norov <ynorov@caviumnetworks.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Ingo Molnar <mingo@redhat.com>,
	Arnaldo Carvalho de Melo <acme@kernel.org>,
	Alexander Shishkin <alexander.shishkin@linux.intel.com>,
	Jiri Olsa <jolsa@kernel.org>,
	Adrian Hunter <adrian.hunter@intel.com>,
	Kan Liang <kan.liang@intel.com>, Wang Nan <wangnan0@huawei.com>,
	Michael Ellerman <mpe@ellerman.id.au>
Subject: Re: [PATCH v2] tools/perf: Fix the mask in regs_dump__printf and
Date: Mon, 20 Jun 2016 11:18:18 +0200	[thread overview]
Message-ID: <20160620091818.GC27702@krava> (raw)
In-Reply-To: <1466412241-27502-1-git-send-email-maddy@linux.vnet.ibm.com>

On Mon, Jun 20, 2016 at 02:14:01PM +0530, Madhavan Srinivasan wrote:
> When decoding the perf_regs mask in regs_dump__printf(),
> we loop through the mask using find_first_bit and find_next_bit functions.
> "mask" is of type "u64", but sent as a "unsigned long *" to
> lib functions along with sizeof(). While the exisitng code works fine in
> most of the case, the logic is broken when using a 32bit perf on a
> 64bit kernel (Big Endian). We end up reading the wrong word of the u64
> first in the lib functions.

hum, I still don't see why this happens.. why do we read the
wrong word in this case?

thanks,
jirka

> first in the lib functions. Proposed fix is to swap the words of the
> u64 to handle this case. This is not endianess swap.
> 

SNIP

  reply	other threads:[~2016-06-20  9:18 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-06-20  8:44 [PATCH v2] tools/perf: Fix the mask in regs_dump__printf and Madhavan Srinivasan
2016-06-20  9:18 ` Jiri Olsa [this message]
2016-06-20  9:27   ` Wangnan (F)
2016-06-20  9:40     ` Jiri Olsa
2016-06-20  9:52       ` Madhavan Srinivasan
2016-06-20  9:19 ` Jiri Olsa

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