| 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: Fri, 23 Nov 2007 13:43:29 +0200 From: Heikki Orsila <shdl@...alwe.fi> To: Daniel Drake <dsd@...too.org> Cc: linux-kernel@...r.kernel.org, davem@...emloft.net, kune@...ne-taler.de, johannes@...solutions.net Subject: Re: [RFC] Documentation about unaligned memory access On Fri, Nov 23, 2007 at 12:15:53AM +0000, Daniel Drake wrote: > Why unaligned access is bad > =========================== > > Most architectures are unable to perform unaligned memory accesses. Any > unaligned access causes a processor exception. "Some architectures are unable to perform unaligned memory accesses, either an exception is generated, or the data access is silently invalid. In architectures that allow unaligned access, natural aligned accesses are usually faster than non-aligned." > In summary: if your code causes unaligned memory accesses to happen, your code > will not work on some platforms, and will perform *very* badly on others. *very* -> *slower* > Natural alignment > ================= Please move this definition before "Why unaligned access is bad". Also, it would be nice to have a table of ISAs: ISA Need Need natural alignment alignment by x -------------------------------------------- m68k No 2 powerpc/ppc Yes Word size x86 No No x86_64 No No -- Heikki Orsila Barbie's law: heikki.orsila@....fi "Math is hard, let's go shopping!" http://www.iki.fi/shd - 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/
Powered by blists - more mailing lists