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
| ||
|
Date: Wed, 24 May 2017 17:09:01 +0200 From: Arnd Bergmann <arnd@...db.de> To: Babu Moger <babu.moger@...cle.com> Cc: Geert Uytterhoeven <geert@...ux-m68k.org>, "David S. Miller" <davem@...emloft.net>, Peter Zijlstra <peterz@...radead.org>, Ingo Molnar <mingo@...hat.com>, sparclinux <sparclinux@...r.kernel.org>, "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>, Linux-Arch <linux-arch@...r.kernel.org>, "devicetree@...r.kernel.org" <devicetree@...r.kernel.org>, "linux-serial@...r.kernel.org" <linux-serial@...r.kernel.org> Subject: Re: CPU_BIG_ENDIAN in generic code (was: Re: [PATCH v3 3/7] arch/sparc: Define config parameter CPU_BIG_ENDIAN) On Wed, May 24, 2017 at 4:45 PM, Babu Moger <babu.moger@...cle.com> wrote: > On 5/24/2017 5:18 AM, Arnd Bergmann wrote: >> On Wed, May 24, 2017 at 11:59 AM, Geert Uytterhoeven >> <geert@...ux-m68k.org> wrote: >>> On Tue, May 23, 2017 at 11:45 PM, Babu Moger <babu.moger@...cle.com> >>> wrote: >>> include/asm-generic/qrwlock.h is also generic, but depends on the >>> architecture to select ARCH_USE_QUEUED_RWLOCKS, which only very few do >>> (x86, and now sparc). >>> >>> I guess the time is ripe for adding (both) symbols to all architectures? >> >> Good idea. I think we can do most of this by adding a few lines to >> arch/Kconfig: >> >> config CPU_BIG_ENDIAN >> bool >> >> config CPU_LITTLE_ENDIAN >> def_bool !CPU_BIG_ENDIAN > > I noticed that even x86 does not define CPU_LITTLE_ENDIAN. Strange. There is no architecture-independent code that tests for CONFIG_CPU_LITTLE_ENDIAN, unlike CONFIG_CPU_BIG_ENDIAN, so that's not very suprising. > With this code all the architecture will default to > CONFIG_CPU_LITTLE_ENDIAN. What I meant is that we have to 'select CPU_BIG_ENDIAN' on all architectures that actually are big-endian: These are all configurable: $ git grep -l linux/byteorder/big_endian.h | xargs grep -l linux/byteorder/little_endian.h arch/arc/include/uapi/asm/byteorder.h arch/arm/include/uapi/asm/byteorder.h arch/arm64/include/uapi/asm/byteorder.h arch/c6x/include/uapi/asm/byteorder.h arch/m32r/include/uapi/asm/byteorder.h arch/microblaze/include/uapi/asm/byteorder.h arch/mips/include/uapi/asm/byteorder.h arch/powerpc/include/uapi/asm/byteorder.h arch/sh/include/uapi/asm/byteorder.h arch/tile/include/uapi/asm/byteorder.h These are always big-endian: $ git grep -l linux/byteorder/big_endian.h | xargs grep -L linux/byteorder/little_endian.h arch/avr32/include/uapi/asm/byteorder.h arch/frv/include/uapi/asm/byteorder.h arch/m68k/include/uapi/asm/byteorder.h arch/openrisc/include/uapi/asm/byteorder.h arch/parisc/include/uapi/asm/byteorder.h arch/s390/include/uapi/asm/byteorder.h arch/sparc/include/uapi/asm/byteorder.h And these are always little-endian: arch/alpha/include/uapi/asm/byteorder.h arch/blackfin/include/uapi/asm/byteorder.h arch/cris/include/uapi/asm/byteorder.h arch/hexagon/include/uapi/asm/byteorder.h arch/ia64/include/uapi/asm/byteorder.h arch/metag/include/uapi/asm/byteorder.h arch/mn10300/include/uapi/asm/byteorder.h arch/score/include/uapi/asm/byteorder.h arch/unicore32/include/uapi/asm/byteorder.h arch/x86/include/uapi/asm/byteorder.h So if we 'select CPU_BIG_ENDIAN' from avr32, frv, m68k, openrisc, parisc, s390 and sparc, this covers all the fixed-endian architectures, and the other ones are those that already have either CPU_BIG_ENDIAN as a 'bool' option, or both as a 'choice'. > I can make it as a separate patch. But I can only test SPARC and little bit > of x86. Is that ok? I think that's ok. Arnd
Powered by blists - more mailing lists