Re: [PATCH 5/7] powerpc/perf: Define big-endian version ofperf_mem_data_src

[Sukadev Bhattiprolu]

Vince Weaver [vince@xxxxxxxxxx] wrote:
| On Sat, 10 Aug 2013, Sukadev Bhattiprolu wrote:
| 
| > 
| >  include/uapi/linux/perf_event.h |   55 +++++++++++++++++++++++++++++++++++++++
| >  1 files changed, 55 insertions(+), 0 deletions(-)
| 
| > +#define __PERF_LE	1234
| > +#define __PERF_BE	4321
| > +
| > +#if defined(__KERNEL__)
| 
| I could be wrong, but I thought files under uapi weren't supposed to 
| contain __KERNEL__ code.  Wasn't that the whole point of uapi?
| 
| Also having the perf_event interface depend on endianess just seems like a 
| complicated mess.  Can't we just declare the interface to be a certain 
| endianess and have the kernel byte-swap as necessary?

Except for the __KERNEL__ check, it looked like this approach would keep
the kernel and user code same. Would it complicate user space ?

I tried to avoid the __KERNEL__ check hack, but like I tried to explain
in the patch, user space and kernel do the endian check differently. 
And, there are about ~300 sites in the kernel with __*ENDIAN checks

Sukadev

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