linux-kernel - Re: [RFC 00/15] x86_64: Optimize percpu accesses

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]

Date:	Thu, 10 Jul 2008 17:03:27 -0400
From:	"H. Peter Anvin" <hpa@...or.com>
To:	Jeremy Fitzhardinge <jeremy@...p.org>
CC:	Christoph Lameter <cl@...ux-foundation.org>,
	"Eric W. Biederman" <ebiederm@...ssion.com>,
	Ingo Molnar <mingo@...e.hu>, Mike Travis <travis@....com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Jack Steiner <steiner@....com>, linux-kernel@...r.kernel.org,
	Arjan van de Ven <arjan@...radead.org>
Subject: Re: [RFC 00/15] x86_64: Optimize percpu accesses

Jeremy Fitzhardinge wrote:
> 
> Percpu on i386 hasn't been a point of discussion.  It works fine, and 
> has been working fine for a long time.  The same mechanism would work 
> fine on x86-64.  Its only "issue" is that it doesn't support the broken 
> gcc abi for stack-protector.
> 
> The problem is all zero-based percpu on x86-64.
> 

Well, x86-64 has *two* issues: limited range of offsets (regardless of 
if we do RIP-relative or not), and the stack-protector ABI.

I'm still trying to reproduce Mike's setup, but I suspect it can be 
switched to RIP-relative for the fixed-offset (static) stuff; for the 
dynamic stuff it's all via pointers anyway so the offsets don't matter.

	-hpa
--
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/