Messages in this thread | | | Date | Tue, 12 Aug 2014 23:51:34 -0700 | From | "H. Peter Anvin" <> | Subject | Re: [PATCH v2] arch: Kconfig: Let all little endian architectures define CPU_LITTLE_ENDIAN explicitly |
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On 08/12/2014 10:32 PM, Chen Gang wrote: > > Yeah, we need. > >> The solution you suggest assumes that an arch is either little or big endian. >> But we cannot ignore the hybriads that can do both. >> > > For the architectures which can do both, for me, they are: sh, powerpc, > m32r, and mips (may mark CPU_LITTLE_ENDIAN), also are: arm/arm64, and > c6x (may mark !CPU_BIG_ENDIAN). > > For the architectures which only support little endian: x86, and ia64. > > The left, I assumes they are big endian (no any 'ENDIAN' can be found > in their Kconfig files). In my memory, except related with Intel, all > are (or support) big endian. >
I'm quite certain that is wrong. From memory, for example, I believe CRIS is littleendian, and sure enough:
: tazenda 103 ; less arch/cris/include/uapi/asm/byteorder.h #ifndef _CRIS_BYTEORDER_H #define _CRIS_BYTEORDER_H
#include <linux/byteorder/little_endian.h>
#endif
As far as I know, endianism is always a compile-time option on Linux, so we should be able to relatively easily define the architecture so that we either have hardwired littleendian, bigendian, or prompt.
-hpa
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