RE: [PATCH v2 1/6] powerpc/perf: Define big-endian version of perf_mem_data_src

David Laight
2017-03-06T14:59:59Z

From: Peter Zijlstra
> Sent: 06 March 2017 11:22
> To: Madhavan Srinivasan
> Cc: Wang Nan; Alexander Shishkin; linux-kernel@vger.kernel.org; Arnaldo Carvalho de Melo; Alexei
> Starovoitov; Ingo Molnar; Stephane Eranian; Sukadev Bhattiprolu; linuxppc-dev@lists.ozlabs.org
> Subject: Re: [PATCH v2 1/6] powerpc/perf: Define big-endian version of perf_mem_data_src
>
> On Mon, Mar 06, 2017 at 04:13:08PM +0530, Madhavan Srinivasan wrote:
> > From: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
> >
> > perf_mem_data_src is an union that is initialized via the ->val field
> > and accessed via the bitmap fields. For this to work on big endian
> > platforms, we also need a big-endian represenation of perf_mem_data_src.
>
> Doesn't this break interpreting the data on a different endian machine?

Best to avoid bitfields if you ever care about the bit order.

David