linux-kernel - Re: [PATCH 6/9][v5] powerpc/perf: Define big-endian version of perf_mem_data

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20131003152725.GA1383@us.ibm.com>
Date:	Thu, 3 Oct 2013 08:27:25 -0700
From:	Sukadev Bhattiprolu <sukadev@...ux.vnet.ibm.com>
To:	Michael Ellerman <michael@...erman.id.au>
Cc:	Arnaldo Carvalho de Melo <acme@...stprotocols.net>,
	Michael Ellerman <michaele@....ibm.com>,
	linux-kernel@...r.kernel.org,
	Stephane Eranian <eranian@...gle.com>, linuxppc-dev@...abs.org,
	Paul Mackerras <paulus@...ba.org>,
	Anshuman Khandual <khandual@...ux.vnet.ibm.com>
Subject: Re: [PATCH 6/9][v5] powerpc/perf: Define big-endian version of
 perf_mem_data_src

Michael Ellerman [michael@...erman.id.au] wrote:
| On Tue, Oct 01, 2013 at 05:15:07PM -0700, Sukadev Bhattiprolu wrote:
| > 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.
| > 
| > diff --git a/include/uapi/linux/perf_event.h b/include/uapi/linux/perf_event.h
| > index ca1d90b..846f399 100644
| > --- a/include/uapi/linux/perf_event.h
| > +++ b/include/uapi/linux/perf_event.h
| > @@ -19,6 +19,50 @@
| >  #include <asm/byteorder.h>
| >  
| >  /*
| > + * Kernel and userspace check for endianness in incompatible ways.
| > + * In user space, <endian.h> defines both __BIG_ENDIAN and __LITTLE_ENDIAN
| > + * but sets __BYTE_ORDER to one or the other. So user space uses checks are:
| 
| 
| Why can't you use __BIG_ENDIAN_BITFIELD ?

BTW, any clues on why there are so many different ways of checking endianness ?

Any standards related stuff or just evolution ?

Sukadev

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/