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, 26 Apr 2017 14:29:13 -0700 From: Greg Hackmann <ghackmann@...gle.com> To: hpa@...or.com, Kees Cook <keescook@...omium.org> Cc: Matthias Kaehlcke <mka@...omium.org>, Thomas Gleixner <tglx@...utronix.de>, Ingo Molnar <mingo@...hat.com>, "x86@...nel.org" <x86@...nel.org>, LKML <linux-kernel@...r.kernel.org>, Grant Grundler <grundler@...omium.org>, Michael Davidson <md@...gle.com> Subject: Re: [PATCH v2] x86/mm/kaslr: Use _ASM_MUL macro for multiplication On 04/26/2017 02:24 PM, hpa@...or.com wrote: >>> This really feels like a "fix your compiler" issue. >> >> We already use the other forms, what's so bad about adding mul too? >> And if this lets us build under clang, all the better. >> >> -Kees > > It's not bad per se, but if this doesn't eventually gets fixed in clang we'll have no end of this crap. > AIUI the "problem" is that clang is spilling mix_const into memory rather than assigning it to a register. This is perfectly legal since mix_const has a constraint of "rm". But mul needs a suffix when the input is a memory location, since it can't infer the multiplication width from the input operand anymore. You get the same error message with gcc if you force it to use a memory location, by narrowing the constraint from "rm" to "m".
Powered by blists - more mailing lists